Progress 04/03/00 to 04/02/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? High dietary and unassimilated feedstuff phosphorus excretion by livestock and poultry, uncontrolled nutrient discharges from animal feeding facilities and manure storage areas, and repeated land application of manure can result in excessive phosphorus concentrations in soils and losses of phosphorus to the environment. Outbreaks of Escherichia coli and Pfiesteria have killed fish and caused human illness. The outbreaks are thought to result from the contamination of streams, reservoirs, and estuaries by animal manure organisms and nutrients, mainly phosphorus and nitrogen. The greatest potential for accelerated eutrophication of surface waters usually occurs in watersheds with intensive animal production. Confined animal feeding operations have become targets of stringent discharge containment
regulations. Runoff from livestock pens, poorly designed or maintained manure storage areas, and fields where manure is repeatedly applied presents potential environmental hazards to the overall watershed. The over-enrichment of receiving waters with manure nutrients leads to excessive growth of autotrophs, especially algae and cyanobacteria. The decay of the microflora biomass utilizes dissolved oxygen, which results in hypoxia or anoxia. The lack of oxygen causes the loss of aquatic animals and release of many materials normally bound to bottom sediments, including various forms of complexed phosphorus. Phosphorus is most often the element limiting eutrophication, since many algae are able to obtain nitrogen from the atmosphere. Consequently, the only definitive method for controlling algal blooms and eutrophication is to minimize agricultural phosphorus discharges to surface waters. To address this national problem an improved understanding of phosphorus chemistry, phosphorus
transformation processes in manure and manure amended-soils and the development of rapid analytical methods of phosphorus forms and methods for determining manure and soil phosphorus release to control offsite manure phosphorus discharges are needed. Studies are conducted to determine inorganic and organic forms of phosphorus present in different manures and their bioavailability. The conditions and factors affecting transformations of organic phosphorus and release of phosphate will be determined. Efficacy of key chemical stabilization and liquid and solid phase separation approaches will be evaluated to immobilize or recover excessive soluble phosphorus levels in manure under commonly used handling and storage systems and manure amended soils. The methodology includes analysis of intact samples and sequential extraction and analysis of extracts by mid-infrared spectroscopy, 31P-nuclear magnetic resonance, high performance liquid chromatography, and enzymatic assays. No rapid
methods exist for accurate determination of manure phosphorus content. Current procedures require several days to complete. The research project addresses a major environmental issue facing the US livestock feeding industry, namely, excessive levels of nutrients in manure. The results will help farmers more efficiently manage their animal manure and comply with comprehensive nutrient management plans in threatened watersheds across the country and near major estuaries. 2. List the milestones (indicators of progress) from your Project Plan. Milestone 1 (Year 1-2): Complete survey of phosphorus forms for dairy manure using available colorimetric and near- and mid-infrared spectroscopic methods. Complete studies of hydrolysis of organic phosphorus, extraction methods in manure studies. Develop laboratory- scale manure processing techniques for fast and reproducible phase- separation. Analyze and publish results in peer-reviewed journals. Milestone 2 (Year 2-3): Based on the results
of the phosphorus form survey, conduct studies of mineralization of phosphorus in manure and extraction methodology to identify process control factors. Summarize initial data on relative efficacy of mechanical approach to form the basis for manure treatment and use of organic polymers in phase separation. Milestone 3 (Year 4-5): Depending on the results obtained previously, develop testing procedures that can be used on the farm. All possible effort will be made to develop a small portable spectroscopic procedure/ instrument for rapid manure phosphorus analysis. Evaluate chemical amendments and phosphorus immobilization efficacy results to treat and mitigate phosphorus discharges on the BARC dairy farm. Conduct data analysis and publication of results in peer-reviewed press. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Based on results achieved in
FY 2004, chemical amendments and phosphorus sequestration efficacy of phosphorus sorbents were determined as planned. Milestone Fully Met 2. The anion-exchangers were proven fully effective at retaining and removing P from brown water and dairy wastewater. Milestone Fully Met 3. Data were compiled and the results were published in peer-reviewed media. Milestone Fully Met 4. New research plans were formulated for the synthesis and summary of our understanding of the impacts of manure chemistry on phosphorus behavior and fate in manure as project objectives. Milestone Fully Met 5. Efforts were made to develop a small portable instrument for manure phosphorus determination on farm by near- or mid-infrared diffuse reflectance spectroscopy. The spectroscopic instrumentation development is still under investigation due the determination that using presently currently available methods it was not technically feasible to develop accurate spectroscopic calibrations for phosphorus in manures.
Further experiments will be conducted to refine spectroscopic detection and quantification of orthophosphate and the major organic forms as goals in the new phosphorus research project. Correlations between bioactive forms and characteristic spectral attributes will be conducted. Therefore, based on the overall results of the project, the interaction of manure chemistry and soil chemistry-biochemistry were deemed an important area of research as the state of knowledge must be significantly improved to accurate predict from phosphorus release from manure and manure-amended soil, the environmental phosphorus behavior and transfer of manure inorganic and organic phosphorus to runoff and the land-water interface. Plans were formulated to support the needs of ARS National Program NP206, "Manure and Byproduct Utilization-Nutrient Component" (Focus Area 2 "Innovative Technology for Collection, Storage and Treatment" and Focus Area 3 "Management Tools for Indexing and Evaluating Nutrient
Fate and Transport") in an integrated systems approach. The project will also contribute to: (A) Soil Resource Management National Program (NP 202), specifically to Nutrient Management component, (B) Water Quality and Management National Program (NP 201), specifically to Water Quality Protection and Management, Excess Nutrients components, and (C) Integrated Agricultural Systems National Program (NP207). Milestone Not Met Other 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? Project is scheduled to terminate in April 2005. Based on current project accomplishments a new project (1265-12630-002-00D) has been developed per a milestone for FY2005. 4a What was the single most significant accomplishment this past year? In dairy and poultry manure, the research results show that phytase enzymes, whether innate to the animal digestive system or fed
as dietary enzymes, readily break down manure organic phytate, depending upon the nature and concentrations of the cations phytate is associated with. The process, in effect, increases water-soluble phosphorus content of manure in the presence of external phytases. Thus, the risk of soluble phosphorus loss increases with land applications of manure having elevated levels of organic phosphorus forms or in soluble phosphates. As a result, new regulations in comprehensive nutrient management were established, requiring that phosphorus applications to lands be limited or eliminated to avoid P surpluses. This is a serious issue facing the animal and plant agriculture sector, leaving the producers with limited options or economically acceptable method for managing animal manures. Accurate information about forms of phosphorus in animal manure is important to the accurate determination of phosphorus content and the understanding of the behavior and fate of various manure phosphorus forms
in the environment. The Animal Manure and Byproducts Laboratory scientists developed a novel measurement method for bioactive phosphorus forms that are present as water-soluble and potentially water-soluble inorganic and organic phosphorus. The method was able to characterize the fraction that exists as readily reactive phosphorus and that fraction of phosphorus that slowly become reactive in time in dairy manure, and in liquid or solid manure in general. The readily soluble phosphorus in 107 dairy manure samples collected across the northeast varied considerably between farms, averaging 15% of the manure total phosphorus content. This soluble fraction has been associated with potential phosphorus loss and levels in runoff. Of the remaining 85% of the manure phosphorus, another 15% of the manure total phosphorus was mineral phosphates that were complexed and insoluble in water. These mineral phosphates were displaced and solubilized by large organic complexing agents such as EDTA
or products of decomposition of organic matter in manure or in soils. Undoubtedly, the entire set had a large reserve of organic phosphorus, up to 47% of the total manure phosphorus (in other words, over 55% the remaining insoluble phosphorus) that can be dissolved and released by the phytase enzymes as reactive phosphate-phosphorus. The exchange between complexing agents and initially insoluble phosphorus that are held on manure particles can produce additional water-extractable-phosphate and enzyme-labile organic phosphorus. The majority of these phosphorus forms were associated with calcium and magnesium compounds and to a lesser extent, iron, manganese, and aluminum compounds. The complexity of forms of phosphorus in manure would make it difficult to remedy the lasting effect on a contamination event on an aquatic environment. By the same token, the great diversity of phosphorus forms was found to cause a great deal of difficulties in the development of quick near- and/or mid-
infrared spectroscopic methods. Thus, the mild in situ ligand-based enzymatic method can and was usable to obtain insights about the biological stability of organic phosphates in animal manure. Selected polydentate ligands and fungal phytases were found able to differentiate the various phosphorus reserve pools that ultimately contribute to the solution-phase orthophosphate concentration of dairy manure and manure- amended soils. In a carbon-rich media such as manure and the ubiquitous presence of enzymes that hydrolyze phosphorus-containing compounds, biological and biochemical mechanisms may more adequately reflect the availability of manure phosphorus pools to microorganisms and plants over time. Moreover, these mechanisms can reveal the underlying potential for the timed release and hydrolysis of organic phosphates in complex media to the environment. 4b List other significant accomplishments, if any. Practices to reduce the solubility and bioavailability of phosphorus sources
are gaining wide acceptance in the management of excessive phosphorus in manure and P-enriched soils. However, the behavior of the immobilized phosphorus once released to the environment through land application is largely unknown. The enzymatic phytase-hydrolyzable phosphorus assay and soil phosphorus fractionation study was conducted to elucidate the mechanisms of stabilization and relative extractability of soil phosphorus as affected by calcium and iron-amendments in a benchmark loam and a gravelly loam. Water-extractable dissolved and complexed P forms, that is, bioactive P, and the conventional soil test Mehlich-3 procedure showed that the iron additive reduced water-extractable phosphorus by over 90% when applied at a rate of 1% by weight of amended soil. Soil test P levels in iron-treated soils were reduced, after that remained unchanged up to 16 weeks. The ligand-based phytase-hydrolyzable P assay developed at the Animal Manure and by-products Laboratory, on the other
hand, revealed that the additives effect was transitory; increasing organic bioactive phosphorus was exchangeable and susceptible to enzymatic dephosphorylation over time to revert back to initial soil levels. Calcium carbonate amended at a liming agent and at rate to raise soil pH to near neutrality negated the environmental benefit of applying iron-rich P-immobilizing additives to both soils. The temporary suppression might resolve a short term elevated soluble phosphorus condition; however, the iron hydroxide treatment did not reduce complexed inorganic and organic phytase-hydrolyzable phosphorus solubilization. Therefore, it has been concluded that iron hydroxide, freshly prepared as a chemical amendment and phosphorus sequestration additive, was an ineffective mitigation practice for reducing the long-term risks of P losses from P-enriched soils. 4c List any significant activities that support special target populations. Communicated research results of the transformation of
phytate and the distribution of different forms organic phosphorus associated with cations in manure and soils to researchers at the 15th International Plant Nutrition Colloquium in Beijing to assess the long-term environmental impact of organic nutrient management systems. The phytase- hydrolyzable phosphorus technology was also transferred to colleagues at BARC to evaluate the effects of manure-based organic cropping systems on the formation of stable soil aggregates and the vulnerability of surface- applied organic nutrient sources to particulate P losses due to soil erosion. The technology has also been shared with colleagues of the New England Soil Plant Research Laboratory and used in the study of the fate of poultry litter phosphorus in organic cropping systems of cold regions in partial fulfillment of the requirements of a Ph.D. program of a University of Maine doctoral candidate. Scientists of the Environmental Microbial Safety Research Laboratory, BARC also adopted the
technology to evaluate the concomitant transport of organic P and manure pathogens. 4d Progress report. Information is critically needed on the contribution of manure organic phosphorus such as phytate to the sources and sinks of dissolved phosphorus in the soil-manure-water system. Substantial amounts of organic phosphorus stored in feed grains are not available to the animal and are excreted in feces, contributing to water pollution rather than animal productivity. Organic phytate accounts for 60 to 90% of the stored reserves of phosphorus in grains that include wheat, barley, rice, corn, and soybean. Phytase in saliva catalyzes the breakdown of feed grain and fiber phytate to inorganic phosphorus that is absorbed primarily in the animal gut. However, swine and poultry lack the phytase enzyme to breakdown phytate and excrete most of this form of organic phosphorus. Ruminant livestock, thought able to utilize phytate-P because of microbial phytase enzymes in the rumen, also
excrete a large portion of phytate. The project researchers of the Animal Manure & By- Products Laboratory, Beltsville, MD found unexpectedly significant amounts of phytate-phosphorus in dairy manure in addition to anticipated dietary inorganic phosphorus forms. Therefore, accurate information about various forms of phosphorus in animal manure is important to the understanding of the behavior and fate of manure phosphorus in the environment. A novel measurement method for bioactive phosphorus forms that are present as water-soluble and water-insoluble inorganic and organic phosphorus, was developed to characterize the fraction that exists as readily reactive phosphorus and that fraction of phosphorus that slowly become reactive over time in dairy manure. The readily water- extractable phosphorus in 107 manure samples collected across the northeast varied considerably between farms and averaged 15% of the total phosphorus content. Of the remaining 85% of the manure P, particulate
and insoluble in water, another 15% of the manure total phosphorus was present as complexed mineral phosphates, and by far the entire set had a large reserve of organic phosphorus, up to 47% of the total manure phosphorus (in other words, over 55% the remaining insoluble phosphorus) that can be dissolved and released by the phytase enzymes as reactive phosphate-phosphorus. Therefore, the complexity of forms of phosphorus in manure makes it difficult to remedy the lasting effect on a contamination event on an aquatic environment. An increased understanding and quantification of these phosphorus reserves must be accurately made as they ultimately add to the fast readily reactive phosphorus fraction to become bioactive over time. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Beyond simply decreasing mineral dietary supplement in animal feed formulation to decrease excessive levels of soluble phosphorus in animal manure,
soluble phosphorus reduction strategies also depend upon the efficiency of phytate-phosphorus utilization in the animal as well as controlling the excretion rates of organic phosphorus and dietary phytases enzymes in animal excreta. 1. Controls of manure organic phosphorus breakdown: A major fraction of the total phosphorus in dairy and poultry manure solids is organic in nature. Research results showed that the biological transformations and release of inorganic phosphorus from phytate, a major form of organic phosphorus in animal feed and manure, were significantly modified by the type and quantity of cations associated with phytate. The stability of organic phosphorus may result in differences in the biological release of inorganic phosphate under varying manure handling and storage and the soil environment of where manure was applied. Therefore, effective and successful management of manure on the farm and manure treatment technologies for high-phosphorus animal manure or
manure-amended field soils will depend on (i) our ability to carry out accurate and timely determination phosphorus forms in manure, (ii) our understanding of the release of organic phosphorus of feed fiber and grains that are the major components of manure, and lastly (iii) the physical state and chemistry of the manure suspension. 2. Quick Phosphorus Analysis methods: Difficulties in getting accurate and timely information about phosphorus levels in manure from storage pits or lagoons, or manure stockpiles have led to over-application or variable distribution. a. Chemical and spectroscopic methods. Research using near- and mid- infrared spectroscopy demonstrated that, as presently used, these techniques do not offer promise as a means for rapid and accurate determination of manure P. Near infrared diffuse reflectance spectroscopic (NIRS) analyses of over 200 samples of poultry manure showed that NIRS technique accurately determine nitrogen (ammonium, organic, and total N) and
moisture content of manure using spectral data in the 1100 to 2498 nm range. However, the determination of minerals was not satisfactory due to the lack of spectral absorptions for minerals in the NIR region. Weak correlation of observed and predicted potassium and calcium contents were found. None was found for P, or Mg, Zn, etc. The predictability of mineral content was indirect and dependent upon organic components that were associated with the mineral of interest. In addition, the need for speed and timeliness of measurements also led to evaluations of a hand-held reflectometer for determining soluble phosphorus in dairy manure suspensions and compared the estimated soluble phosphorus concentrations to those obtained in the laboratory using the time-tested molybdate-ascorbic acid colorimetric method. Using 107 dairy manure samples collected from farms across CT, NY, MD, PA, and VA, we evaluated quick methods that included the hydrometer, the electrical conductivity meter,
and the RQFlex reflectometer. The prediction of soluble phosphorus from RQFlex results was greatly improved by including pH and selected manure characteristics. To estimate the manure total phosphorus, it was found that the manure solid contents were related to measures of the slurry specific gravity that were in turn slightly related to total phosphorus content of the manures. Therefore, the RQFlex method is the only viable option for on-site quick estimates of dissolved phosphorus that can be made more robust when supplemented with total solids and pH measurements. b. Enzymatic methods. Enzymatic assays have the advantage of revealing the chemical identity of phosphorus forms in manure as well as reflecting the biological stability of the phosphorus forms. Microorganisms and external and dietary enzymes mediate the bioavailability of organic phosphorus. Changes in the biological conditions will vary widely across manure handling and storage environments and accurate
determination phosphorus forms in manure will help in the prediction of potential loss and in crafting environmental management plans. In a soil or in a carbon- rich media such as manure and the ubiquitous presence of enzymes that hydrolyze P-containing compounds, biological and biochemical mechanisms can more adequately reflect the release and bioavailability of phosphorus forms and pools to microorganisms and plants over time. 3. Manure phosphorus immobilization and removal treatments. In liquid manure, enhancing particulate aggregation concentrated particulate phosphorus in a small volume of solid manure for ease of transport or recycling into feed production system. Our research on soluble and particulate phosphorus removal from dairy manure showed that the particulate separation process is a complex function of manure characteristics, and the processes of coagulation, flotation, and sedimentation to isolate the solid phase and clarify the liquid wastewater. Synergistic effects
of combining cationic organic polymers and phosphorus immobilizing agents exist at low concentrations of aluminum sulfate and iron chloride with organic polymers in dairy manure of total suspended solids between 3 and 10% and reduced particulate and soluble phosphorus. The phosphorus immobilizing amendments worked in dairy manure as they did in solid poultry and cattle manure shown in our previous studies. Soluble phosphorus was reduced when the mixture included fly ash or Al and Fe salts at rates between 1 and 10 g L-1. Liquid manure treatment with combination of organic polymers and phosphorus immobilizing amendments clarified the wastewater, thereby allowing potential water reuse and conservation in manure management practices of confined animal feeding operations. The polymer-amendment treated particulates also maintained their stability in soil. Release of soluble phosphorus from soil amended with treated manure was reduced. In solid manure, our research showed that raw
poultry manure contained high levels of soluble phosphorus. The fractionation of poultry manure showed that another 60% was released by mineral acid and base extractants. The residual fraction that remained after exhaustive extraction was large and deemed to be non-mineral and amounted to about 30% of the total phosphorus of untreated manure. To maintain the option of manure application on croplands, phosphorus immobilization amendments are used to reduce the excessive levels of soluble reactive manure phosphorus and can play a key role in risk minimization strategies for land application of manure. We found that differential affinity for phosphate existed between aluminum- and iron-rich by-products used to reduce soluble reactive phosphorus in animal manure. Unlike metal salts reacting with soluble phosphate when amended to raw manure to immobilize phosphate, amorphous aluminum oxides in water-treatment residuals are not likely to lower the mixture pH that would lower the
phosphorus immobilization efficiency of aluminum salts. The research results showed that the use of relatively inexpensive industrial by-products, such as coal-combustion ash, and municipal by-products containing aluminum and iron to reduce soluble phosphorus in animal manure before land application is a practical manure management practice and a promising component of an overall non-point source pollution prevention strategy. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? During FY05, scientists of the Environmental Microbial Safety Research Laboratory, BARC adopted the bioactive phosphorus technology to evaluate the concomitant transport of organic P and manure pathogens. Information on dietary phytase in environmental management and manure
phosphorus fractionation was also communicated to researchers and educators at the Institute of Tropical Biology, Vietnam Academy of Science and Technology, and researchers at Nong Lam University, HCM, Vietnam. Research information on fate of organic phosphorus in manure was communicated to representative of the NE Dairy Association for potential applications in organic phosphorus recovery.
Impacts
(N/A)
Publications
- Dao, T.H. 2004. Ligands and phytase hydrolysis of organic phosphorus in soils amended with dairy manure. Agronomy Journal. 96(4):1188-1195.
- Green, V.S., Dao, T.H., Cavigelli, M.A., Flanagan, D.C. 2004. Phosphorus fractions in aggregates of organic and conventional cropping systems [abstract]. American Society of Agronomy Annual Meeting Abstracts [CDROM]. No. 4279.
- Schwartz, R.C., Dao, T.H. 2005. Phosphorus extractability of soils amended with stockpiled and composted cattle manure. Journal of Environmental Quality. 34:970-978.
- Jayasundera, S., Schmidt, W.F., Reeves Iii, J.B., Dao, T.H. 2005. Direct 31p nmr spectroscopic measurement of phosphorous forms in dairy manures. International Journal of Food, Agriculture, and the Environment. 3(2):335- 340.
- Dao, T.H., Reeves III, J.B., Zhang, H. 2004. Ligand-based enzymatic fractionation of bioactive phosphorus in dairy manure: fast and time- dependent processes [abstract]. American Society of Agronomy. Annual Meeting Abstracts CDROM No. 5217.
- Lugo-Ospina, A., Dao, T.H., Van Kessel, J.S., Reeves III, J.B. 2005. Evaluation of quick tests for dissolved phosphorus determination in dairy manures. Environmental Pollution. 135:155-162.
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Progress 10/01/03 to 09/30/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? High dietary and unassimilated feedstuff phosphorus excretion by livestock, uncontrolled nutrient discharges from animal feeding facilities and manure storage areas, and repeated land application of manure result in excessive phosphorus concentrations in soils and losses of phosphorus to the environment. Non-point sources of agricultural phosphorus, along with other manure components can cause accelerated eutrophication and anoxia in nearby surface waters and pose potential risks to the overall watershed, airshed, and human health. To address this national problem an improved understanding of phosphorus chemistry, phosphorus transformation processes in manure and manure amended-soils and the development of rapid analytical methods of phosphorus forms and methods for determining manure and soil
phosphorus release to control offsite manure phosphorus discharges are needed. Studies are conducted to determine inorganic and organic forms of phosphorus present in different manures and their bioavailability. The conditions and factors affecting transformations of organic phosphorus and release of phosphate will be determined. Efficacy of key chemical stabilization and liquid and solid phase separation approaches will be evaluated to immobilize or recover excessive soluble phosphorus levels in manure under commonly used handling, storage, and application systems and manure amended soils. The methodology includes analysis of intact samples and sequential extraction and analysis of extracts by pyrolysis-GC-MS, mid-infrared spectroscopy, 31P-nuclear magnetic resonance, high performance liquid chromatography, and enzymatic assays. No rapid methods exist for accurate determination of manure phosphorus content. Current procedures require several days to complete. The research
project addresses a major environmental issue facing the US livestock feeding industry, namely, excessive levels of nutrients in manure. The results will help farmers more efficiently manage their animal manure and comply with comprehensive nutrient management plans in threatened watersheds across the country and near major estuaries. Outbreaks of Escherichia coli and Pfiesteria have killed fish and caused human illness. The outbreaks are thought to result from the contamination of streams, reservoirs, and estuaries by animal manure organisms and nutrients, mainly phosphorus (P) and nitrogen (N). The greatest potential for accelerated eutrophication of surface waters usually occurs in watersheds with intensive animal production. Confined animal feeding operations have become targets of stringent discharge containment regulations. Runoff from livestock pens, poorly designed or maintained manure storage areas, and fields where manure is repeatedly applied presents potential
environmental hazards to the overall watershed. The over-enrichment of receiving waters with manure nutrients leads to excessive growth of autotrophs, especially algae and cyanobacteria. The decay of the microflora biomass utilizes dissolved oxygen, which results in hypoxia or anoxia. The lack of oxygen causes the loss of aquatic animals and release of many materials normally bound to bottom sediments, including various forms of complexed P. Phosphorus is most often the element limiting eutrophication, since many algae are able to obtain N from the atmosphere. Consequently, the only definitive method for controlling algal blooms and eutrophication is to minimize agricultural phosphorus discharges to surface waters. The project specifically addresses research gaps identified in National Program 206 Manure and Byproduct Utilization-Nutrient Component Problem Area 2, Efficient and cost-effective methods for manure handling, treatment and storage, and Problem Area 3, Methods developed
to determine nutrient concentrations and nutrient availability in manure, byproducts, and soil treated with manure or byproducts. The project also contributes to: (A) Soil Resource Management National Program (NP 202), specifically to Nutrient Management component, (B) Water Quality and Management National Program (NP 201), specifically to Water Quality Protection and Management, Excess Nutrients components, and (C) Integrated Agricultural Systems National Program (NP207). The multi-disciplinary effort will provide a basic understanding of manure chemistry and the integration of that knowledge into decision support tools and environmentally sound manure management practices on the farm. 2. List the milestones (indicators of progress) from your Project Plan. The milestones for the project to be addressed include - the development of calibrations for phosphorus in dairy and poultry manures for the eventual design and construction of a small handheld instrument for manure phosphorus
determination on farm by either visible, near- or mid-infrared diffuse reflectance spectroscopy. - the development of organic phosphorus extraction and bioavailability methods and knowledge of interactions with selected anion exchangers to identify process control factors. - The integration of that chemical knowledge will also be implemented to transfer the quick tests for soluble P and new knowledge of organic phosphorus transformations to help improve the determination of land application rates based on manure phosphorus bioavailability on the farm. 3. Milestones: A. The milestones that were scheduled to be met in FY2004 include - the development of calibrations for phosphorus in dairy and poultry manures by either visible, near- or mid-infrared diffuse reflectance spectroscopy. As the efforts were unsuccessful at determining a means to analyze manure phosphorus spectroscopically, research was concentrated on developing more non-spectroscopic methods for such determinations
with better accuracy than those based on colorimetry, conductivity, and specific gravity. - Studies of organic P extraction methodology and characterization of the fraction that exists as readily reactive phosphorus and that fraction of phosphorus that slowly become reactive in time. - Initial data on interactions with selected anion exchangers that were completed to identify phosphorus desorption controlling factors and the relative efficacy of phosphorus removal approach were summarized and forms the basis for developing benchtop-scale treatment and use of organic polymers and mineral exchangers in solid coagulation and soluble P reduction in wastewater. B. In FY2005, new research plans will be formulated for the synthesis and summary of our understanding of the impacts of manure chemistry on phosphorus behavior and fate in manure. Based on accomplishments of the current CRIS, the interaction of manure chemistry and soil chemistry- biochemistry is an important area of research.
Plans will be formulated to support the needs of ARS National Program NP206, "Manure and Byproduct Utilization-Nutrient Component" (Focus Area 2 "Innovative Technology for Collection, Storage and Treatment" and Focus Area 3 "Management Tools for Indexing and Evaluating Nutrient Fate and Transport") in an integrated systems approach. Applying the bioactive phosphorus fractionation method we developed, phosphorus transformations experiments will be conducted to identify matrix characteristics that influence phytate persistence and dietary phosphorus extractability in paired samples of feed and manure. In FY 2006, studies will be conducted to refine spectroscopic detection and quantification of organic and bioactive forms of phosphorus. Correlations between bioactive phosphorus forms and characteristic spectral attributes will be conducted. Experiments will be conducted to refine infrared spectroscopy and apply x-ray fluorescence for determining the role of polyvalent counterions in
the condensation and solubility of organic forms. These mechanisms are critical to a basic understanding of their role in the storage and subsequent bioavailability in soils amended with organic nutrient sources. In FY 2007, long-term measurements of mineralizable manure nutrients along with bioactive phosphorus in benchmark soils will be implemented to derive knowledge on rates of mineralization and a database for manure and soil characteristics for collaborative development of manure nutrient mobilization model. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY2004. In dairy and poultry manure, the research showed that phytase enzymes, whether innate to the animal digestive system or fed as dietary enzymes, readily brake down manure organic phytate. The process, in effect, increases water-soluble phosphorus content of manure in the presence of external phytase enzymes. Thus, the risk of soluble phosphorus loss
increases with land applications of manure having elevated levels of organic phosphorus forms or in soluble phosphates. Accurate information about forms of phosphorus in animal manure is important to the understanding of the behavior and fate of manure phosphorus in the environment. The Animal Manure and Byproducts Laboratory scientists developed a novel measurement method for bioactive phosphorus forms that are present as water-soluble and potentially water-soluble inorganic and organic phosphorus. The method was able to characterize the fraction that exists as readily reactive phosphorus and that fraction of phosphorus that slowly become reactive in time in dairy manure, and in liquid or solid manure in general. The readily soluble phosphorus in 107 dairy manure samples collected across the northeast varied considerably between farms, averaging 15% of the manure total phosphorus content. This soluble fraction has been associated with potential phosphorus loss and levels in
runoff. However, the conventional dilution method yielded notably higher dissolved phosphorus than those determined in undiluted manure liquid phase. The relationship between the two measures collapsed as the time of equilibration in the conventional dilution method increased. This highly variable increase in the apparent water-soluble phosphorus was attributed to the concurrent release of phosphate- phosphorus following breakdown of organic phosphorus forms under favorable laboratory conditions of analysis. Of the remaining 85% of the manure phosphorus, another 15% of the manure total phosphorus was mineral phosphates that were complexed and insoluble in water. These mineral phosphates were displaced and solubilized by large organic complexing agents such as EDTA or products of decomposition of organic matter in manure or in soils. By far the entire set had a large reserve of organic phosphorus, up to 47% of the total manure phosphorus (in other words, over 55% the remaining
insoluble phosphorus) that can be dissolved and released by the phytase enzymes as reactive phosphate-phosphorus. The exchange between complexing agents and initially insoluble phosphorus that are held on manure particles can produce additional water- extractable-phosphate and enzyme-labile organic phosphorus. The majority of these phosphorus forms were associated with calcium and magnesium compounds. Therefore, the complexity of forms of phosphorus in manure would make it difficult to remedy the lasting effect on a contamination event on an aquatic environment. The fractionation method helped increase our understanding of these phosphorus reserves which must be accurately measured as they ultimately add to the readily reactive phosphorus fraction and become bioactive over time. B. Other Significant Accomplishments. Managing large volumes of dilute animal manure wastewater is a common challenge on dairy farms. Dairy wastewater is often used to irrigate field crops. Quick
measurements and timely information about manure nutrient content are needed because of the time delay and cost of laboratory analytical methods and the need to minimize the risks of phosphorus over-application and losses of dissolved phosphorus in runoff from fields treated with manure wastewater. Overall, the handheld reflectometer appeared to be an acceptable method for the quick determination of concentrations of soluble phosphorus in samples of dairy manure. Sample pre-treatment such as dilution, centrifugation, filtration etc. is not needed, thus reduces time and cost of measurements. Manure soluble phosphorus concentrations measured using the reflectometer were related to standard laboratory measures of soluble phosphorus concentrations. Inclusion of pH measurements improved the prediction of manure soluble phosphorus from results obtained with the reflectometer for 95% of the manure samples. In addition, an ammonium- nitrogen module is also available to get a more complete
picture of soluble nutrient contents in dairy manure to improve on-farm manure nutrient budgets. To estimate manure total phosphorus loading for land application, a separate measurement of the suspension's specific gravity can serve as a rough surrogate indicator of total phosphorus content for a wide range of dairy manures, from very dilute to thick concentrated manure slurries. Also, soluble and colloidal phosphorus should be removed from the liquid phase to avoid further loading and phosphorus buildup on lands already high in phosphorus commonly found in watersheds with a high concentration of confined animal feeding operations. Combinations of organic coagulants and mineral phosphorus immobilization chemicals were shown to be effective in solid-liquid separation and soluble phosphorus removal from the liquid. Chemical precipitation, however, defers the phosphorus removal from a diluted liquid to a more concentrated solid fraction. Exchanger materials offer an alternate approach
to recover phosphorus instead of immobilizing phosphorus. Materials possessing such properties include natural and synthetic zeolites and coal-combustion ash. While natural zeolites do not bind phosphate, modified and synthetic zeolites, and fly ash have significant capacity to bind phosphate from solution, in particular dairy wastewaters. The adsorbed phosphorus can be re- extracted by water. The mineral sorbents all demonstrated their usefulness as temporary phosphorus storage to treat animal wastewaters. These capabilities make the sorbents, fly ash in particular, very versatile phosphate sorbent for low cost reclamation and treatment processes. The zeolite-based sorbent technology can also be developed to enhance water conservation because as treatment and clarification can be made, allowing the water to be reused in animal production such as flush water. C. Significant Accomplishments/Activities that support special target populations. Communicated research results of the
transformation of phytate and the distribution of different forms organic phosphorus associated with cations in manure and soils to researchers at Mississippi State and Fort Collins, CO, and the Fourth International Phosphorus Workshop to further the development of options for phosphorus removal and recovery in animal manure. D. Progress Report. Information is critically needed on the contribution of manure organic phosphorus such as phytate to the sources and sinks of dissolved phosphorus in the soil-manure-water system. Substantial amounts of organic phosphorus stored in feed grains are not available to the animal and are excreted in feces, contributing to water pollution rather than animal productivity. Organic phytate accounts for 60 to 90% of the stored reserves of phosphorus in grains that include wheat, barley, rice, corn, and soybean. Phytase in saliva catalyzes the breakdown of feed grain and fiber phytate to inorganic phosphorus that is absorbed primarily in the animal
gut. However, swine and poultry lack the phytase enzyme to breakdown phytate and excrete most of this form of organic phosphorus. Ruminant livestock, thought able to utilize phytate-P because of microbial phytase enzymes in the rumen, also excrete a large portion of phytate. The project researchers of the Animal Manure & By- Products Laboratory, Beltsville, MD found unexpectedly significant amounts of phytate-phosphorus in dairy manure in addition to anticipated dietary inorganic phosphorus forms. Therefore, accurate information about various forms of phosphorus in animal manure is important to the understanding of the behavior and fate of manure phosphorus in the environment. A novel measurement method for bioactive phosphorus forms that are present as water-soluble and water-insoluble inorganic and organic phosphorus, was developed to characterize the fraction that exists as readily reactive phosphorus and that fraction of phosphorus that slowly become reactive over time in
dairy manure. The readily water- extractable phosphorus in 107 manure samples collected across the northeast varied considerably between farms and averaged 15% of the total phosphorus content. Of the remaining 85% of the manure P, particulate and insoluble in water, another 15% of the manure total phosphorus was present as complexed mineral phosphates, and by far the entire set had a large reserve of organic phosphorus, up to 47%of the total manure phosphorus (in other words, over 55% the remaining insoluble phosphorus) that can be dissolved and released by the phytase enzymes as reactive phosphate-phosphorus. Therefore, the complexity of forms of phosphorus in manure makes it difficult to remedy the lasting effect on a contamination event on an aquatic environment. An increased understanding and quantification of these phosphorus reserves must be accurately made as they ultimately add to the fast readily reactive phosphorus fraction to become bioactive over time. 5. Describe the
major accomplishments over the life of the project, including their predicted or actual impact. Beyond simply decreasing mineral dietary supplement in animal feed formulation to decrease excessive levels of soluble phosphorus in animal manure, soluble phosphorus reduction strategies also depend upon the efficiency of phytate-phosphorus utilization in the animal or controlling dietary phosphorus and organic phosphorus excretion rates. Post- excretion manure treatment and recovery technologies depend upon accurate and timely measurements of inorganic and organic phosphorus and stabilization and recovery of the organic phosphorus forms. Difficulties in getting accurate and timely information about phosphorus levels in manure from storage pits or lagoons, or manure stockpiles have led to over-application or variable distribution. Research using near- and mid- infrared spectroscopy demonstrated that, as presently used, these techniques do not offer promise as a means for rapid and
accurate determination of manure P. Near infrared diffuse reflectance spectroscopic (NIRS) analyses of over 200 samples of poultry manure showed that NIRS technique accurately determine nitrogen (ammonium, organic, and total N) and moisture content of manure using spectral data in the 1100 to 2498 nm range. However, the determination of minerals was not satisfactory due to the lack of spectral absorptions for minerals in the NIR region. Weak correlation of observed and predicted potassium and calcium contents were found. None was found for P, or Mg, Zn, etc. The predictability of mineral content was indirect and dependent upon organic components that were associated with the mineral of interest. In addition, the need for speed and timeliness of measurements also led to evaluations of a hand-held reflectometer for determining soluble phosphorus in dairy manure suspensions and compared the estimated soluble phosphorus concentrations to those obtained in the laboratory using the
time-tested molybdate-ascorbic acid method. Using 107 dairy manure samples collected from farms across CT, NY, MD, PA, and VA, we evaluated quick methods that included the hydrometer, the electrical conductivity meter, and the reflectometer. Neither of the other two quick methods gave accurate estimates of soluble phosphorus. The prediction of soluble phosphorus from reflectometer results was greatly improved by including pH and selected manure characteristics. The soluble phosphorus results of the standard laboratory and the handheld reflectometer matched for 95% of the samples. To estimate the manure total phosphorus, it was found that the manure solid contents were related to measures of the slurry specific gravity that were in turn slightly related to total phosphorus content of the manures. Therefore, the reflectometer method is the only viable option for on-site quick estimates of dissolved phosphorus that can be made more robust when complemented with total solids and pH
measurements. Under these circumstances, the dissolved phosphorus quick test can provide near real-time information on soluble manure nutrient content across a wide range of handling and storage conditions on dairy farms and quick estimates of potential soluble phosphorus losses in runoff following land applications of manure. A major fraction of the total phosphorus in dairy and poultry manure solids is organic in nature. Research results showed that the biological transformations and release of inorganic phosphorus from phytate, a major form of organic phosphorus in animal feed and manure, were significantly modified by the type of cations associated with phytate. Therefore, the stability of organic phosphorus may result in differences in the biological release of inorganic phosphate under varying manure handling and storage and the soil environment of where manure was applied. There is increasing interest on post-excretion treatments to chemically bind or remove soluble
inorganic phosphorus in manure before it is applied to fields as many soils in watersheds with intensive animal agriculture contain excessive levels of nutrients, especially phosphorus due to repeated heavy applications of animal manure. In liquid manure, enhancing particulate aggregation concentrated particulate phosphorus in a small volume of solid manure for ease of transport or recycling into feed production system. Our research on soluble and particulate phosphorus removal from dairy manure showed that the particulate separation process is a complex function of manure characteristics, and the processes of coagulation, flotation, and sedimentation to isolate the solid phase and clarify the liquid wastewater. Synergistic effects of combining cationic organic polymers and phosphorus immobilizing agents exist at low concentrations of aluminum sulfate and iron chloride with organic polymers in dairy manure of total suspended solids between 3 and 10% and reduced particulate and
soluble phosphorus. The phosphorus immobilizing amendments worked in dairy manure as they did in solid poultry and cattle manure shown in our previous studies. Soluble phosphorus was reduced when the mixture included fly ash or Al and Fe salts at rates between 1 and 10 g L-1. Liquid manure treatment with combination of organic polymers and phosphorus immobilizing amendments clarified the wastewater, thereby allowing potential water reuse and conservation in manure management practices of confined animal feeding operations. The polymer-amendment treated particulates also maintained their stability in soil. Release of soluble phosphorus from soil amended with treated manure was reduced. In solid manure, our research showed that raw poultry manure contained high levels of soluble phosphorus. The fractionation of poultry manure showed that another 60% was released by mineral acid and base extractants. The residual fraction that remained after exhaustive extraction was large and
deemed to be non-mineral and amounted to about 30% of the total phosphorus of untreated manure. To maintain the option of manure application on croplands, phosphorus immobilization amendments are used to reduce the excessive levels of soluble reactive manure phosphorus and can play a key role in risk minimization strategies for land application of manure. We found that differential affinity for phosphate existed between aluminum- and iron-rich by-products used to reduce soluble reactive phosphorus in animal manure. Unlike metal salts reacting with soluble phosphate when amended to raw manure to immobilize phosphate, amorphous aluminum oxides in water-treatment residuals are not likely to lower the mixture pH that would lower the phosphorus immobilization efficiency of aluminum salts. The research results showed that the use of relatively inexpensive industrial by-products, such as coal-combustion ash, and municipal by-products containing aluminum and iron to reduce soluble
phosphorus in animal manure before land application is a practical manure management practice and a promising component of an overall non-point source pollution prevention strategy. In summary, effective and successful remediation technologies for high- phosphorus animal manure or manure-amended field soils will depend on (i) our ability to carry out accurate and timely determination phosphorus forms in manure, and (ii) our understanding of the release of organic phosphorus of feed fiber and grains that are the major components of manure. Microorganisms and external and dietary enzymes mediate the bioavailability of organic phosphorus. Changes in the biological conditions will vary widely across manure handling and storage environments and accurate determination phosphorus forms in manure will help in the prediction of potential loss and in crafting environmental management plans. 6. What science and/or technologies have been transferred and to whom? When is the science and/or
technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Manure phosphorus fractionation information was communicated to researchers at Mississippi State and Fort Collins, CO. Provided assistance to Washington County Cooperative Extension Service, Maryland on soil organic phosphorus and swine manure under selection and identification of potential phosphorus accumulators. Technical presentations were made at professional meetings of the American Society of Agronomy, and the fourth International Phosphorus Workshop on "Critical Evaluation of Options for Reducing Phosphorus Loss from Agriculture", Wageningen, the Netherlands. Presented partitioning and phosphorus recovery approaches to representatives of the WR Grace company for potential development of their plant's waste stream in phosphorus recovery. Advised and assisted a nursery-landscaping business in
Loveland, CO with the use of zeolites in recovery and availability of phosphorus in composts. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Organic phosphorus hydrolysis and reactivity in dairy manure. Presented at the meeting of SERA-Information Exchange Group 17, Fort Collins, CO. June 26, 2002. Particulate and dissolved phosphorus chemical separation and phosphorus release from treated dairy manure: Continuing Education Self-Study Course. Certified Crop Advisor AgProfessional 2003(12):38-41. http://www. agprofessional.com. 2003.
Impacts
(N/A)
Publications
- Dao, T.H. 2003. How dietary phytases can increase manure organic phosphorus mobilization [abstract]. American Society of Agronomy Annual Meeting Abstracts CD-ROM. No. S11-dao381545-P.
- Green, V.S., Cavigelli, M.A., Dao, T.H., Flanagan, D.C. 2003. Cropping system effect on distribution of C, N, and P among aggregate size classes [abstract]. American Society of Agronomy Annual Meeting Abstracts [CDROM]. A08-green642204-Poster.
- Dao, T.H., Daniel, T.C. 2003. Particulate and dissolved phosphorus chemical separation and phosphorus release from treated dairy manure: Continuing Education Self-Study Course. Certified Crop Advisor AgProfessional 12/2003:37-41. http://www.agprofessional.com.
- Dao, T.H., Reeves III, J.B., Zhang, H. 2004. Reducing the mobilization of organic phosphorus in dairy wastewaters: chemistry and role of active and intermediate pools. In: Chardon, W.J. and G.F. Koopmans (eds.), Critical Evaluation of Options for Reducing Phosphorus Loss from Agriculture. Fourth International Phosphorus Workshop Proceedings 2004:14.
- Reeves III, J.B., Lugo-Ospina, A., Dao, T.H., Van Kessel, J.S. 2003. Evaluation of quick tests for dissolved phosphorus determination in dairy manures. [abstract]. American Society of Agronomy Abstracts. Annual Meeting Abstracts. November 2-6, 2003. No. A05-reeves921387-P.
- SCHWARTZ, R.C., DAO, T.H. 2003. NET PHOSPHORUS EXTRACTABILITY FROM SOILS AMENDED WITH CATTLE MANURE. ANNUAL MEETING ABSTRACTS 2003. ASA-CSSA-SSSA, DENVER, CO. 2003 CDROM.
- Dao, T.H. 2003. Competitive anion sorption effects on dairy wastewater dissolved phosphorus extraction with zeolite-based sorbents. International Journal of Food, Agriculture, and the Environment. 1(3):263-269.
- DAO, T.H. 2004. Organic ligant effects on the enzymatic dephosphorylation of myo-inositol hexakis dihydrogenphosphate in dairy wastewater. Journal of Environmental Quality. 33(1):349-358.
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? High dietary and unassimilated feedstuff phosphorus (P) excretion by livestock, uncontrolled nutrient discharges from animal feeding facilities and manure storage areas, and repeated land application of manure can result in excessive P concentrations in soils and losses of P to the environment. Non-point sources of agricultural P, along with other manure components can cause accelerated eutrophication and anoxia in nearby surface waters and pose potential risks to the overall watershed, airshed, and human health. To address this national problem an improved understanding of P chemistry, P transformation processes in manure and manure amended-soils and the development of rapid analytical methods of P forms and methods for determining manure and soil P release to control offsite manure P discharges are needed. Studies are conducted to determine inorganic and organic forms of P present in
different manures and their relative bioavailability. The conditions and factors affecting transformations of organic P and release of phosphate-P will be determined. Efficacy of key chemical P stabilization and liquid and solid phase separation approaches will be evaluated to immobilize or recover excessive soluble reactive P levels in manure under commonly used handling, storage, and application systems and manure amended soils. Methodology will include analysis of intact samples and sequential extraction and analysis of extracts by pyrolysis-GC-MS, mid-infrared spectroscopy, 31P-nuclear magnetic resonance, high performance liquid chromatography, and enzymatic assays. No rapid methods exist for accurate determination of manure P content. Current procedures require several days to complete. 2. How serious is the problem? Why does it matter? The research project addresses a major environmental issue facing the US livestock feeding industry, namely, excessive levels of nutrients in
manure. The results will help farmers more efficiently manage their animal manure and comply with comprehensive nutrient management plans in threatened watersheds across the country and near major estuaries. Outbreaks of Escherichia coli and Pfiesteria have killed fish and caused human illness. The outbreaks are thought to result from the contamination of streams, reservoirs, and estuaries by animal manure organisms and nutrients, mainly phosphorus (P) and nitrogen (N). The greatest potential for accelerated eutrophication of surface waters usually occurs in watersheds with intensive animal production. Confined animal feeding operations have become targets of stringent discharge containment regulations. Runoff from livestock pens, poorly designed or maintained manure storage areas, and fields where manure is repeatedly applied presents potential environmental hazards to the overall watershed. The over-enrichment of receiving waters with manure nutrients leads to excessive growth of
autotrophs, especially algae and cyanobacteria. The decay of the microflora biomass utilizes dissolved oxygen, which results in hypoxia or anoxia. The lack of oxygen causes the loss of aquatic animals and release of many materials normally bound to bottom sediments, including various forms of complexed P. Phosphorus is most often the element limiting eutrophication, since many algae are able to obtain N from the atmosphere. Consequently, the only definitive method for controlling algal blooms and eutrophication is to minimize agricultural P discharges to surface waters. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? The project specifically addresses research gaps identified in National Program 206 Manure and Byproduct Utilization-Nutrient Component (Problem Areas 1, 2, 3, and 4). The multi-disciplinary effort will provide a basic understanding of manure chemistry and the integration of that knowledge into decision
support tools and environmentally sound manure management practices on the farm. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY2003. Current feed formulation and manure management practices have contributed to high levels of soluble and phytase-hydrolyzable phosphorus forms in animal manure. The research results demonstrated that a large fraction of manure organic phosphorus, namely phytate phosphorus, is converted to soluble phosphate-P by phytase and other phosphatase enzymes present in soil and animal manure. Phytate, largely indigestible to swine and poultry, is excreted in manure. A large phytase-hydrolyzable fraction is also found native to manure of cattle, although rumen microflora possess necessary enzymes to breakdown phytate. In effect, external or dietary phytase enzymes increase water-extractable phosphorus content of a large number of dairy and poultry farm manure samples. Implications for managing
manure from livestock or poultry that were fed rations containing phytase enzymes are that such manures can be high in phytate- derived dissolved P, in addition to mineral dietary P. Mobilization and hydrolysis of complexed phytate are further increased as organic ligands are shown to overcome the inhibitory effect of cations such as Ca, Fe, or Al. Metabolic byproducts with cation-chelating properties in animal wastewaters can change the environment of extracellular phytase enzymes, and solubilize bound phytate and possible other forms of organic P for hydrolysis. B. Other Significant Accomplishment(s). 1. To evaluate the effects of farm manure management and lagoon storage on the forms of P, project researchers determined water-extractable phosphorus, complexed mineral phosphates, phytase-hydrolyzable phosphorus (PHP), and total phosphorus contents in manure samples collected from dairy farms across five states of the northeastern US. Water-extractable and complexed inorganic
phosphates accounted between 15 to 30% of total P, whereas up to 40 to 80% of the total P is in organic forms that were hydrolyzed by phytase enzymes and released as soluble P. Water- extractable P was not related to manure total P, PHP, or manure total solids. Manure PHP is related to total P content. Therefore, a large fraction of the manure organic P forms can be converted to soluble and bioactive phosphate-P by phytase enzymes and its management is related to the control and management of the particulate fraction of liquid manure. 2. The project researchers demonstrated the use of lognormal distribution function to predict the release of manure and soil soluble P in collaboration with Dr. M. Cavigelli, ARS, Beltsville, MD. Dissolved P transfer to runoff water can increase with surface applications and shallow soil incorporation of animal manure. Information is needed regarding water-extractable nutrient release during manure decomposition to quantify that potential transfer to
runoff in permanent pastures and conservation tillage systems. The adoption of the use of lognormal distributions to describe potential dissolved carbon, nitrogen, and phosphorus release from manures and manure-amended soils also shorten predictive methodologies that require long and laborious incubations. Further efforts in integrating such an approach in a systematic tool to evaluate the quality of organic nutrient sources are being made in collaborative research and develop environmentally sound and sustainable farm manure utilization practices. 3. The influence of manure characteristics and P application rate on the net extractability of P was collaboratively studied with Dr. R. Schwartz, ARS, Bushland, TX, to predict plant availability of the manure-amended soil P in different soils by a variety of extractants. The efficiency with which soil and manure P was extracted relative to fertilizer P differed significantly among soil testing extractants used in the major regions of the
US. It appears that manure characteristics must be considered in estimating P release in addition to the rates of application to improve the estimate and prediction of the net availability of manure phosphorus in manure-amended soils. Further efforts are being made in integrating that chemical knowledge into decision support tools to devise environmentally sound manure management practices on the farm. C. Significant Accomplishments/Activities that support special target populations. Presented scientific information to members of the USDA-Natural Resource Conservation Service Nutrient Team on the issue of managing organic phosphorus in animal manure and on lands where repeated applications of dairy and poultry manure were made. Communicated the use of log-normal predictive model to the NRCS-Soil Survey Staff, Lincoln, NE to assess mineralizable nutrients in US benchmark soils. Communicated research results of the speciation of phytate and polyvalent cations to researchers at the
University of Tennesee and at an international conference of the International Water Association, Aquatech to further the development of phosphorus removal and recovery in modified zeolitic materials and as struvite or magnesium-ammonium phosphate in animal wastewaters. D. Progress Report Information is critically needed on the contribution of manure organic P such as phytate to the sources and sinks of dissolved P in the soil- manure-water system. Substantial amounts of organic P stored in feed grains are not available to the animal and contribute to water pollution rather than animal productivity. Organic phytate accounts for 60 to 90% of the stored reserves of P in grains that include wheat, barley, rice, corn, and soybean. Phytase in saliva catalyzes the breakdown of feed grain and fiber phytate to inorganic P that is absorbed primarily in the animal gut. However, swine and poultry lack the phytase enzyme to breakdown phytate and excrete most of this form of organic phosphorus.
Ruminant livestock, thought able to utilize phytate-P because of microbial phytase enzymes in the rumen, also excrete a large portion of phytate. The project researchers of the Animal Manure By-Products Laboratory, Beltsville, MD found unexpectedly significant amounts of phytate-P in dairy manure. In dairy and poultry manure, our research shows that the enzymes readily brake down phytate and, in effect, increase manure water-extractable P content and the risk of soluble P loss and offsite discharges. These results suggest that the practice of adding phytase enzymes to animal diet may have an important implication on soluble P content of manure. In association with phytate, calcium cation was found to activate the breakdown of phytate at low concentration. However, as calcium or aluminum or iron in dietary mineral supplements increases, the degradation of phytate and release of soluble P are severely reduced, averaging 30% less at ratio of 1 to 6 Al or Fe to phytate-P and
reaching over 99% when the cation to phytate-P ratio was on a 1 to 1 basis. Therefore, the nature and amount of the cation associated with phytate control phytate physical state and its susceptibility to enzymatic breakdown that may lead to differences in phytate persistence and bioavailability in manure and potentially where manure is land applied. However, in manure where organic carbon can act as complexation agents, the chemistry of phosphorus becomes more complex. Organic ligands are shown to have the ability to overcome the inhibitory effect of polyvalent cations, to the point of promoting the hydrolysis of the manure PHP fraction that is otherwise unaccessible. Therefore, the experimental results suggested that organic anions are necessary ingredients of an accurate method for determining the PHP fraction of manure. Also, organic anions in animal wastewaters mobilize complexed phytate and possible other inositol phosphates. Organic anions to phytate charge concentration
ratio must be about 3 to overcome the inhibitory effect of polyvalent cations, particularly when the manure contains high concentrations of trivalent cations. Metabolic byproducts with cation- chelating properties in animal wastewaters can change the environment of extracellular phytases, and mobilize complexed phytate and possible other forms of organic P for hydrolysis. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Beyond simply decreasing mineral dietary supplement in animal feed formulation to decrease excessive levels of soluble P in animal manure, soluble P reduction strategies also depend upon the efficiency of phytate- P utilization in the animal or controlling dietary P and organic P excretion rates. Post-excretion manure treatment and recovery technologies depend upon accurate and timely measurements of inorganic and organic P and stabilization and recovery of the organic P forms. Difficulties in getting
accurate and timely information about phosphorus levels in manure from storage pits or lagoons, or manure stockpiles have led to over-application or variable distribution. Research using near- and mid-infrared spectroscopy demonstrated that, as presently used, these techniques do not offer promise as a means for rapid and accurate determination of manure P. Near infrared diffuse reflectance spectroscopic (NIRS) analyses of over 200 samples of poultry manure showed that NIRS technique accurately determine nitrogen (ammonium, organic, and total N) and moisture content of manure using spectral data in the 1100 to 2498 nm range. However, the determination of minerals was not satisfactory due to the lack of spectral absorptions for minerals in the NIR region. Weak correlation of observed and predicted potassium and calcium contents were found. None was found for P, or Mg, Zn, etc'. The predictability of mineral content was indirect and dependent upon organic components that were
associated with the mineral of interest. In addition, the speed and timeliness of measurements also prompted us to determine the suitability of a hand-held reflectometer for determining dissolved phosphorus (DP) in dairy manure suspensions and compared the estimated DP concentrations to those obtained in the laboratory using the time-tested molybdate-ascorbic acid (MAA) method. Using dairy manure samples (n=107) collected from farms across CT, NY, MD, PA, and VA, we evaluated quick methods that included the hydrometer, the electrical conductivity meter,and the RQFlex reflectometer. Neither of the other two quick methods gave accurate estimates of soluble P. The prediction of manure DP from RQFlexe results was greatly improved by including pH and selected manure characteristics. Under these circumstances, the research results indicated that the quick RQFlex method is a viable option for on- site measurements of dissolved N and P concentrations in farm dairy manure for
environmentally sound practices of irrigation of dairy wastewater. A major fraction of the total P in dairy and poultry manure solids is organic in nature. Research results showed that the biological transformations and release of inorganic P from phytate-P, the key form of organic P in animal feed and manure, were significantly modified by the type and amounts of cation present. Therefore, the differential stability of organic polyphosphates may result in differences in the biological release of inorganic P under varying manure handling and storage and the soil environment of where manure was applied. Thus, there is increasing interest on post-excretion treatments to chemically bind or remove DRP in manure before it is applied to fields as many soils in watersheds with intensive animal agriculture contain excessive levels of nutrients, especially P due to repeated heavy applications of animal manure. In liquid manure, enhancing particulate aggregation concentrated particulate P in
a small volume of solid manure for ease of transport or recycling into feed production system. Our research on soluble and particulate P removal from dairy manure showed that the particulate separation process is a complex function of manure characteristics, and the processes of coagulation, flotation, and sedimentation to isolate the solid phase and clarify the liquid wastewater. Synergistic effects of combining cationic organic polymers and P immobilizing agents exist at low concentrations of aluminum sulfate and iron chloride with organic polymers in dairy manure of total suspended solids between 3 and 10% and reduced particulate and soluble P. The P immobilizing amendments worked in dairy manure as they did in solid poultry and cattle manure shown in our previous studies. Solution DRP was reduced when the mixture included fly ash or Al and Fe salts at rates between 1 and 10 g L-1. Liquid manure treatment with combination of organic polymers and P immobilizing amendments
clarified and improved wastewater quality, thereby allowing water reuse and conservation in manure management practices of confined animal feeding operations. The polymer-amendment treated particulates also maintained their stability in soil. Release of soluble phosphorus from soil amended with treated manure was reduced. In solid manure, our research showed that raw poultry manure contained high levels of soluble P, averaging about 2034 ppm. The fractionation of poultry manure showed that another 60% was released by mineral acid and base extractants. The residual fraction that remained after exhaustive extraction was large and deemed to be non-mineral and amounted to about 30% of the total P of untreated manure. To maintain the option of manure application on croplands, P immobilization amendments are used to reduce the excessive levels of soluble reactive manure P and can play a key role in risk minimization strategies for land application of manure. We found that differential
affinity for phosphate-P existed between aluminum- and iron-rich by-products used to reduce soluble reactive P in animal manure. Unlike metal salts reacting with soluble phosphate-P when amended to raw manure to immobilize phosphate, amorphous aluminum oxides in water- treatment residuals are not likely to lower the mixture pH that would lower the P immobilization efficiency of aluminum salts. The research results showed that the use of relatively inexpensive industrial by- products, such as coal-combustion ash, and municipal by-products containing aluminum and iron to reduce soluble P in animal manure before land application is a practical manure management practice and a promising component of an overall non-point source pollution prevention strategy. In summary, effective and successful remediation technologies for high- phosphorus animal manure or manure-amended field soils will depend on (i) our ability to carry out accurate and timely determination P forms in manure, and (ii)
our understanding of the release of organic P of fiber and grains that are the major components of manure. Microorganisms and extracellular enzymes mediate the bioavailability of organic phosphorus. Changes in the biological conditions will be less controllable and more likely will vary widely across manure handling and storage environments. 6. What do you expect to accomplish, year by year, over the next 3 years? FY 2004 - Contingent on successful development of a means to determine manure P by either visible, near- or mid-infrared diffuse reflectance spectroscopy, efforts will be made to develop calibrations for P in dairy and poultry manures for the eventual development of a small handheld instrument for manure P determination on farm by either visible, near- or mid-infrared diffuse reflectance spectroscopy. If efforts are unsuccessful at determining a means to determine manure P spectroscopically, then research will be concentrated on developing more non-spectroscopic methods for
such determinations with better accuracy than those based on conductivity and specific gravity now available. Studies of organic P extraction methodology and interactions with selected anion exchangers will be completed to identify process control factors. Initial data on relative efficacy of chemical approach will be summarized and forms the basis for developing benchtop-scale treatment and use of organic polymers and mineral exchangers in solid coagulation and soluble P reduction in wastewater. FY 2005 - Based on results achieved in FY 2003 and 2004, efforts will be made to develop a small portable instrument for manure P determination or an alternate non-spectroscopic quick test for manure P. Integrating quick analytical tests into manure treatment and processing systems to reduce water-soluble P and recover organic polyphosphates at the animal production facilities must also be developed and optimized based on the process-level knowledge and results of the CRIS project. Also,
this will be the last year of the CRIS project. Plans will be formulated for the synthesis and summary of our understanding of the impacts of manure chemistry on P behavior and fate in manure. The integration of that chemical knowledge into decision support tools will also be implemented to devise environmentally sound manure management practices on the farm. FY 2006 - Based on results achieved in the current CRIS, the interaction of manure chemistry and soil chemistry-biochemistry is an important area of research as the state of knowledge must be significantly improved to accurate predict from P release from manured soil, the environmental P behavior and transfer of manure inorganic and organic P to runoff and the land-water interface. Plans will be formulated for this future line of research to support the needs of ARS National Program NP206. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to
the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Results have been reported at field days and producer meetings such as the Chesapeake Bay Day and Sustainable Agriculture Field Day and the annual BARC Field Day. Manure P management information was communicated to representatives of Resource Conservation organizations such as the Environmental Defense, the Department of Agriculture of Florida, Office of Agricultural Water Policy. Technical presentations were made at professional meetings of the American Society of Agronomy, the Soil Science Society of America, the Water-Environment Federation and workshops of the Southern Extension Research Activity -Information Exchange Group 17 (SERA-17), and at the 2002 International Conference of AQUATECH on 'From Nutrient Removal to Recovery', Amsterdam, Netherlands. Presented dairy manure phosphorus forms, partitioning and phosphorus recovery
approaches to representatives of the South Florida Water District about reducing agricultural phosphorus loading to Lake Okeechobee, FL. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Organic P hydrolysis and reactivity in dairy manure. Presented at the meeting of SERA-Information Exchange Group 17, Fort Collins, CO. June 26, 2002.
Impacts
(N/A)
Publications
- Reeves III, J.B., Van Kessel, J.S. Spectroscopic analysis of dried dairy manures. Near- versus mid-infrared diffuse reflectance spectroscopy for the analysis of dried dairy manures. Journal of Near-Infrared Spectroscopy. 2002. v. 10. p. 91.
- Reeves III, J.B., Van Kessel, J.S. Influence of ash on the fiber composition of dried dairy manures. Environmental Pollution. 2002. v. 120. p. 239-244.
- Dao, T.H. Polyvalent Cation Effects on myo-inositol hexakis dihydrogenphosphate Enzymatic Dephosphorylation in Dairy Wastewater. Journal of Environmental Quality. 2003. v. 32. p. 694-701.
- Dao, T.H., Cavigelli, M. Mineralizable Carbon, Nitrogen, and water- extractable Phosphorus Release from Stockpiled and Composted Manure, and Manure-Amended Soils. Agronomy Journal. 2003. v. 95. p. 405-413.
- Dao, T.H. 2002. Particle Destabilization And Removal From Concentrated Dairy Manure Suspensions. 14 p. Water Environment Federation Joint Residuals and Biosolids Conference, February 19-22, 2003. Baltimore, MD.
- Reeves, J.B., Jayasundera, S., Schmidt, W. What does 31P-NMR tells us about P in dairy manures. Agronomy Abstracts CD-ROM. 2002. Abstract No. S11-Reeves170030-P.
- Dao, T.H., Daniel, T.C. Reducing Particulate and Dissolved Phosphorus in Dairy Manure Suspensions. Agronomy Abstracts CD-ROM. 2002. Abstract No. S11-Dao170030-P.
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Progress 10/01/01 to 09/30/02
Outputs
1. What major problem or issue is being resolved and how are you resolving it? High dietary phosphorus (P) excretion by livestock, uncontrolled nutrient discharges from animal feeding facilities and manure storage areas, and repeated land application of manure can result in excessive P concentrations in soils and losses of P to the environment. Non-point sources of agricultural P, along with other manure components can cause accelerated eutrophication and anoxia in nearby surface waters and pose potential risks to the overall watershed, airshed, and human health. To address this national problem, an improved understanding of the chemistry and transformation processes affecting P in manure and manure amended- soils is needed. Rapid and accurate methods for measuring P forms in manure and those for determining manure and soil P release are essential to the development of practices to control offsite manure P discharges. No rapid methods exist for accurate
determination of manure P content. Current procedures require several days to complete. Studies are conducted to determine inorganic and organic forms of P present in different manures and their relative availability to crops and runoff water. Methodology will include analysis of intact samples and sequential extraction and analysis of extracts by pyrolysis-gas chromatography-mass spectrometry, mid-infrared spectroscopy, 31P-nuclear magnetic resonance, enzymatic assays, and high performance liquid chromatography. Predictions of dissolved P release, as a function of environmental factors from specific manures, must be improved to accurately determine the potential for P transfer to runoff and/or subsurface transport from land-applied manures. The conditions and factors affecting the transformations of organic P and release of phosphate-P will be determined. Remedial chemical stabilization techniques and liquid and solid phase separation approaches will be evaluated for efficacy of
reduction and recovery of excessive bioactive P levels in manure and manure amended soils. 2. How serious is the problem? Why does it matter? The research project addresses a major environmental issue facing the US livestock feeding industry, namely, excessive levels of nutrients in animal manure. The results will help farmers more efficiently manage their animal manure and comply with comprehensive nutrient management plans in threatened watersheds across the country and near major estuaries. Outbreaks of Escherichia coli and Pfiesteria have killed fish and caused human illness. The outbreaks are thought to result from the contamination of streams, reservoirs, and estuaries by organisms and nutrients found in animal manure, mainly nitrogen (N) and P. The greatest potential for accelerated eutrophication of surface waters usually occurs in watersheds with intensive animal production. Confined animal feeding operations (CAFOs) have become targets of stringent discharge
containment regulations. Runoff from livestock pens, poorly designed or maintained manure storage areas, and fields where manure is repeatedly applied present potential environmental hazards to the overall watershed. The over-enrichment of receiving waters with mineral nutrients leads to excessive growth of autotrophs, especially algae and cyanobacteria. The decay of the increased microflora biomass utilizes dissolved oxygen, which results in hypoxia or anoxia in the water body. The lack of oxygen causes the loss of aquatic fauna and release of materials normally bound to bottom sediments, including various chemical forms of P. Phosphorus is most often the element limiting eutrophication because algae are able to obtain N from the atmosphere. Consequently, the only definitive method for controlling algal blooms and eutrophication is to minimize agricultural P inputs to surface waters. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has
been assigned? The project specifically addresses research gaps identified in National Program 206 "Manure and Byproduct Utilization-Nutrient Component" (Problem Areas 1, 2, 3, and 4). The multi-disciplinary effort will provide a basic understanding of manure chemistry and the integration of that knowledge into decision support tools and environmentally sound manure management practices on the farm. 4. What was your most significant accomplishment this past year? A. Single most significant accomplishment during FY2002: Current feed formulation and livestock production practices have contributed to high levels of soluble phosphorus in animal manure and non- point sources of agricultural P, along with other manure components would cause accelerated quality degradation in nearby surface waters and outbreaks of pathogenic E. coli and Pfiesteria that have killed fish and caused human illness. The results of phosphorus studies conducted at the Animal Manure and Byproducts Laboratory
(AMBL), Beltsville, MD demonstrate that a large fraction of manure organic phosphorus, namely phytate forms, are converted to soluble phosphate by phytase and other phosphatase enzymes, even in the manure of ruminant livestock. The studies establish that external phytase enzymes increase water- extractable phosphorus content in a large number of dairy and poultry farm manure samples, and, consequently raising the risk of soluble phosphorus discharges to the environment. In addition to reducing mineral phosphorus supplements in animal diets, priority consideration should be given to controlling dietary phytase enzymes and organic phosphorus forms in excreted manure, in order to abate unwanted high levels of bioactive soluble phosphorus in manure, and assist farmers achieve their comprehensive whole-farm nutrient management plans in watersheds with intensive animal agriculture. B. Other Significant Accomplishment(s), if any: 1. To evaluate the accuracy of quick analytical methods for
P in dairy manure, the project researchers evaluated available tests such as electrical conductivity, specific gravity, and a small portable spectrometer using test strips in collaboration with Dr J.S. Van Kessel (Animal Waste Pathogen Lab, Beltsville, MD). Results showed that none of the individual measurements were accurate for determining soluble P in dairy manures, however, a combination of total solid content, suspension pH, and the test strip measurements yield an adequate estimate of water- soluble P in dairy manure containing a wide range of total solids. These quick measurements will prove valuable in determining the water-soluble P fraction that is correlated to the P level in runoff water. Also, this research demonstrated that better quick methods are needed if farmers are going to be able to determine land application rates that also require the knowledge of manure organic and total P contents with any significant degree of accuracy. 2. In collaboration with Drs. W.
Schmidt and S. Jayasundera (Environmental Quality Lab, Beltsville, MD), the project scientists conducted studies to determine forms of P as they exist in dairy manure using P-31 nuclear magnetic resonance (NMR) techniques. Approximately half of the 107 manures, selected based on other available compositional data (fiber, ash, N, etc.), were analyzed and the results demonstrated that typical Eastern US dairy manures contain significant amounts of organic P compounds and the results are particularly significant in that they demonstrated that large amounts of dairy manure P can exist in forms which would not be detected by measuring soluble inorganic P. These results agree with the findings of the phytase enzyme studies which showed that a large fraction of manure organic P is readily converted to soluble and bioactive phosphate-P by phytase enzymes. Therefore, the chemical composition and bioavailability data are especially significant because they demonstrate that organic P forms
will be degraded in manure and soils and released over time under favorable biological conditions, with the potential to contaminate surface and ground water or promote algal growth which will impair the quality of recreational or drinking water supplies. C. Significant Accomplishments/Activities that support special target populations: Assisted and transfered research information to the Zero Waste Alliance on anaerobic digestion and P management in digester effluent. Information was included in a manure treatment technology assessment report and favorable recommendations of manure P recovery strategies were based on AMBL work with modified zeolites and sorbents in Western Oregon dairies. Presented scientific information to members of the USDA-Natural Resource Conservation Service Nutrient Team on the issue of managing organic phosphorus in animal manure and on lands which had received repeated applications of dairy and poultry manure. Participated in 2001 public field days to
illustrate current best manure management practices for dairy operations. D. Progress Report: Rapid methods for nutrient analysis are needed to determine nutrient content of animal manure because a timely knowledge of P and N contents in these highly variable plant nutrient sources is essential to making accurate P-based land application or wastewater irrigation rate determinations. The suitability of a hand-held reflectometer for measuring dissolved phosphorus (DP) in dairy manure was evaluated and the results were compared to those obtained in the laboratory using the molybdate-ascorbic acid (MAA) method. Dairy manure samples (n=107) were collected from farms across five states in the Northeastern US. The RQFlex reflectometer yields lower DP estimates that are marginally related to molybdate-reactive phosphorus (MRP) concentrations. An improved relationship was found for 102 of the 107 samples upon excluding samples of highest MRP values. The prediction of manure DP from RQFlex
results is greatly improved when we include pH and total solid content of the manure suspensions. Under these circumstances, the results show that the RQFlex method is a viable option for quick on-site measurements of soluble P content of dairy manure. In addition to DP, information is critically needed on the contribution of organic P such as phytate to the sources and sinks of DP in the soil- manure-water system. Organic phytate accounts for 60 to 90% of the stored P reserves in grains, which include corn, wheat, soybean, barley, and rice. Forages and grains are fed to livestock in various proportions, depending upon stages of growth and energy requirements of animal life cycle and production goals. Phytase enzymes catalyze the breakdown of feed grain and fiber phytate to inorganic P that is absorbed primarily in the animal gut. However, swine and poultry lack the phytase enzyme to breakdown phytate and excrete most of this form of organic P. Ruminant livestock, thought able
to assimilate phytate-P because of degradation by microbial enzymes in the rumen, can excrete phytate. Substantial amounts of organic P stored in feed grains are not available to the animal and can contribute to water quality and ecological degradation rather than animal productivity. Remediation strategies or technologies to reduce excessive P levels in manure and P-loaded soils depend on our understanding of the release of P of fiber and grains that are the major components of manure. Unexpectedly, significant amounts of phytate-P were found in dairy manure. Our results show that the external enzymes increase manure water-soluble P content of dairy and poultry manure, and, consequently raise the risks of DP loss and offsite discharges. The results suggest that the practice of adding dietary phytase enzymes to animal rations may have an important implication on soluble P content of manure. Furthermore, we determine that the biochemical environment of phytate controls the
susceptibility of the organic P molecule to enzymatic breakdown. In association with phytate, Ca2+ was observed to enhance the breakdown of phytate at low concentration. However, as Ca2+ or aluminum (Al) or iron (Fe) content increases, the degradation of phytate and release of soluble P are severely reduced. Therefore, the nature and amount of the cation associated with phytate determine the physical state of phytate and control its susceptibility to enzymatic breakdown, and, as such lead to differences in phytate persistence and bioavailability in manure and potentially where manure is land applied. 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact? Beyond simply decreasing mineral dietary supplement levels in animal feed formulation to achieve cutback in excessive levels of P in manure, the success of P reduction strategies also depends upon the efficiency of phytate-P utilization by the animal. Otherwise,
post-excretion treatment technologies for recovering manure P are critically needed. Again, the success of remedial strategies depends upon accurate and timely measurements of inorganic and organic P forms in manure and the fundamental understanding of the chemistry of stabilization and recovery of all P forms. Difficulties in getting accurate and timely information about N and P levels in manure from storage pits, lagoons, or manure stockpiles have led to variable field distribution and over-application of manure nutrients. Research using near- and mid-infrared spectroscopy demonstrated that, as presently used, these techniques do not offer promise as a means for rapid and accurate determination of manure P. Near infrared diffuse reflectance spectroscopic (NIRS) analyses of over 200 samples of poultry manure showed that the NIRS technique accurately determine nitrogen (ammonium, organic, and total N) and moisture content of manure using spectral data in the 1100 to 2498 nm range.
However, the determination of minerals was not satisfactory due to the lack of spectral absorptions for minerals in the NIR region. Weak correlation of observed and predicted potassium and calcium contents were found. None was found for P, or Mg, Zn, etc?. The predictability of mineral content was indirect and dependent upon organic components that were associated with the mineral of interest. In addition, the need for speed and timeliness of measurements also leads us to evaluate a hand-held reflectometer for determining dissolved phosphorus (DP) in dairy manure suspensions and compare the results to those obtained in the laboratory using the time-tested molybdate-ascorbic acid (MAA) method. Using dairy manure samples (n=107) collected from farms across CT, NY, MD, PA, and VA, quick methods and tools that included the hydrometer, the electrical conductivity meter, and the RQFlex reflectometer were compared. The portable relectometer yields lower DP estimates that were slightly
related to molybdate-reactive phosphorus (MRP) measurements. Neither of the other two quick methods gave accurate estimates of soluble P. Upon excluding five samples with highest MRP content, the prediction of manure DP from RQFlex results was significantly improved by including pH and selected manure characteristics. Under these circumstances, the research results suggested that the quick RQFlex method is a viable option for on-site measurements of dissolved N and P contents in farm dairy manure for irrigating croplands with dairy wastewater. However, application rates for manure slurries containing any substantial amount of solids will not be accurate as total loading of N and P cannot be determined using these quick methods. A major fraction of the total P in dairy and poultry manure solids is organic in nature. The results showed that biological transformations and release of inorganic P from phytate-P, the key form of organic P in animal feed and manure, were significantly
modified by the type and amounts of cation associated with phytate molecules. The differential stability of organic polyphosphates may result in differences in the biological breakdown and release of P under varying manure handling and storage and in the soil environment of where manure was applied. Thus, there is increasing interest on post-excretion treatments to chemically bind or remove DP in manure before application to fields because many soils in watersheds with intensive animal agriculture already contain excessive levels of nutrients, especially P due to repeated heavy applications of animal manure. In liquid manure, enhancing liquid-solid separation and concentrating particulate P in a small volume of solid manure can facilitate the transport and recycling into feed production system. The research results suggest that the liquid-solid separation process is a complex function of manure characteristics, and the processes of coagulation, flotation, and sedimentation to
isolate the solid phase and clarify the liquid wastewater. Multiple control processes were operational when water treatment organic polymers and P immobilizing manure additives (aluminum sulfate, iron chloride, and coal-combustion ash) were used for promoting the coagulation of dairy manure solids. A synergistic effect exists when organic polymers were used in combination with the mineral additives, enhancing the coagulation of dairy manure suspended solids. The combinations also remove particulate and soluble P from solution more effectively than the individual additives. The congealed solids entrap a large amount of wastewater, producing large flocs to potentially facilitate particle filtration in the solid-liquid separation process. Soluble P is reduced consistently when the mixture include coal- combustion ash at any rate of addition, or aluminum sulfate, iron chloride salts at rates less than 10 g/L. Higher Al3+ or Fe3+ levels re- dispersed manure solids and increased soluble
P in solution. The combination of organic polymers and mineral P immobilizing additives removed solids, clarified and improved wastewater quality, in so doing allow water reuse and conservation in the animal production operations. In solid manure, AMBL phosphorus research shows that raw poultry manure contains high levels of soluble P, averaging about 11% of manure total P. About 60% is released by mineral acid and base extractants and was likely associated with mineral phosphates, such as iron and calcium phosphates. The remaining fraction (about 30%) appears to be organic in nature. The high levels of DP in manure must be reduced to abate the potential ecological risks of land application of manure and P immobilization additives can play a key role in reducing such risks. Results of reactivity studies using municipal and industrial aluminum- and iron-containing by-products demonstrated that, on a 1 to 1 molar basis, Fe is more efficient than Al in immobilizing DP, enhancing the
formation of water-insoluble iron phosphates in treated manure. Furthermore, the results demonstrate that coal-combustion ash and municipal water-treatment additives and residuals are efficient and practical manure management additives to reduce soluble P in animal manure before land application. In combination with liquid-solid separation, anaerobic digestion, or composting to stabilize manure N, mineral by-products can be a promising component of an overall non-point source pollution prevention strategy to reduce the environmental risks of recycling of manure back into agronomic production. In summary, effective and successful manure processing and treatment technologies depend upon (i) our ability to carry out accurate and timely determination inorganic and organic P forms in manure, and (ii) the improved understanding of the release of organic P of fiber and grains that are the major components of manure. The research results establish that extracellular enzymes mediate the
transformations and bioavailability of organic P. Changes in the biological conditions, however, will be less controllable and more likely will vary widely across manure handling and storage, and soil environments. 6. What do you expect to accomplish, year by year, over the next 3 years? FY 2003 : Results of the analytical survey of P forms will be compiled for dairy manure, and preliminary investigations undertaken for beef and poultry manure. Nuclear magnetic resonance spectroscopic procedures will be completed to determine the forms of P in 107 dairy manure samples from the North Atlantic region. Correlation studies between available data on reflectometer, hydrometer, near- and mid-infrared spectroscopy and specific fractions of manure P will be undertaken to test their applicability and the quick tests' ability to predict the conventional laboratory analytical results. Efforts will be made to develop other quick test procedures for determining manure P, assuming that efforts
with infrared spectroscopy are not successful. Adding to the manure P management toolbox, bioavailability of manure organic P can be measured by the enzymatic assay coupled with chromatographic separation of P forms. The conditions and mechanisms of transformations of organic P forms will be studied to accurately determine the release of bioactive P in extracts of manured field soils. FY 2004 - Contingent on successful development of a means to determine manure P by either visible, near- or mid-infrared diffuse reflectance spectroscopy, efforts will be made to develop calibrations for P in dairy and poultry manures for the eventual development of a small handheld instrument for manure P determination on farm by either visible, near- or mid-infrared diffuse reflectance spectroscopy. If efforts are unsuccessful, research will be concentrated on developing additional non- spectroscopic methods with better accuracy than those based on conductivity and specific gravity. Studies of
organic P extraction methodology and interactions with selected anion exchangers will be completed to identify process control factors. Initial data will be summarized and used to develop proof-of-concept laboratory-scale treatments. Manure phosphorus availability to plants and runoff water will be determined in multi-year comparisons of legume-cereal forage systems. Field results will be summarized to determine the systems' relative P removal efficiency and the effects of manure treatments on P chemistry and bioavailability in high P manure-amended soils. FY 2005 - Based on results achieved in FY 2003 and 2004, efforts will be made to develop a small portable instrument for manure P determination or an alternate non-spectroscopic quick test for manure P. Integrating quick analytical methods into manure treatment and processing systems to reduce water-soluble P and recover organic polyphosphates at the animal production facilities must also be developed and optimized based on the
process-level knowledge gained during the past four years. Also, this will be the last year of the CRIS project. Plans will be formulated for the synthesis and summary of the understanding of the impact of manure chemistry on P behavior and fate in manure. The integration of that chemical knowledge into decision support tools will also be implemented to devise environmentally sound manure management practices on the farm. The interactions of manure chemistry and soil chemistry-biochemistry remain to be elucidated as the current state of knowledge must be significantly improved to accurate predict release, environmental behavior, and transfer of organic P in land-applied manure to runoff and the aquatic environment. 7. What technologies have been transferred and to whom? When is the technology likely to become available to the end user (industry, farmer other scientist)? What are the constraints, if known, to the adoption durability of the technology? Results have been reported at
field days and producer meetings such as the 1999 Chesapeake Bay Day and Sustainable Agriculture Field Day at BARC and the annual BARC Field Day. Technical presentations were made at professional meetings of the American Society of Agronomy, the Soil Science Society of America and workshops of the Southern Extension Research Activity -Information Exchange Group 17 (SERA-17). Presented dairy manure P fractionation/ partitioning and P recovery approaches to representatives of the Zero Waste Alliance and PGE. Applications for developmental grants have been initiated with these stakeholders to fund collaborative development and implementation of phosphorus recovery of a Willamette Valley on-farm anaerobic digestion-biogas production system. 8. List your most important publications and presentations, and articles written about your work (NOTE: this does not replace your review publications which are listed below) Presented "Chemical treatments for coagulation of particulates and P
removal from dairy slurry manure", Southern Education and Research Activity Information Exchange Group 17, July 20, 2001; "Organic P hydrolysis and reactivity in dairy manure", presented at the meeting of Southern Education and Research Activity-Information Exchange Group 17, Fort Collins, CO. June 26, 2002. The sequestration and recovery research has been described and recommended for scale-up and on-farm implementation in a Zero Waste Alliance manure P reduction technologies evaluation report to Portland Gas and Electric.
Impacts
(N/A)
Publications
- Dao, T.H., Sikora, L.J., Hamasaki, J., Chaney, R.L. Manure phosphorus extractability as affected by Al and Fe by-products and aerobic composting. Journal of Environmental Quality. 2001. v. 30. p. 1693-1698.
- Reeves, J.B. III, Van Kessel, J.A.S. Spectroscopic analysis of dried manures. Near- versus mid-infrared diffuse reflectance spectroscopy for the analysis of dried dairy manures. Journal of Near Infrared Spectroscopy. 2002. v. 10. p. 93-101.
- Dao, T.H., Daniel, T.C. Particulate and dissolved phosphorus chemical separation and phosphorus release from treated dairy manure. Journal of Environmental Quality. 2002. v. 31. p. 1388-1398.
- Dao, T.H., Schmidt, W. Calcium (II) amendment effects on phytate-P hydrolysis. Agronomy Abstracts No. S11-DAO115255P. ASA-CSSA-SSSA, Madison, WI. 2001.
- Bowman, R.S., Dao, T.H. Competitive sorption of animal wastewater anions by zeolite-based sorbents. Agronomy Abstracts No. S11-DAOP. ASA-CSSA-SSSA, Madison, WI. 2001.
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Progress 10/01/00 to 09/30/01
Outputs
1. What major problem or issue is being resolved and how are you resolving it?
High dietary phosphorus (P) excretion by livestock, uncontrolled nutrient discharges from animal feeding facilities and manure storage areas, and repeated land application of manure can result in excessive P concentrations in soils and losses of P to the environment. Non- point sources of agricultural P, along with other manure components can cause accelerated eutrophication and anoxia in nearby surface waters and pose potential risks to the overall watershed, airshed, and human health. To address this national problem an improved understanding of P chemistry, transformation processes in manure and manured-soils, and the development of rapid analytical methods of P forms and potential methods for determining manure and soil P release to control offsite manure P discharges are needed. Studies are conducted to determine inorganic and organic forms of P present in different manures and their relative bioavailability. The conditions and factors affecting transformations of organic P
and release of phosphate-P will be determined. Efficacy of key chemical P stabilization and liquid and solid phase separation approaches will be evaluated to immobilize or recover excessive soluble reactive P levels in manure under commonly used handling, storage, and application systems and manured soils. Methodology will include analysis of intact samples and sequential extraction and analysis of extracts by pyrolysis-GC-MS, mid-infrared spectroscopy, 31P-nuclear magnetic resonance, and high performance liquid chromatography. No rapid methods exist for accurate determination of manure P content. Current procedures require several days to complete.
2. How serious is the problem? Why does it matter?
The research project addresses a major environmental issue facing the US livestock feeding industry. The results will help farmers more efficiently manage their animal manure and comply with comprehensive nutrient management plans in threatened watersheds across the country and near major estuaries. Outbreaks of Escherichia coli and Pfiesteria have killed fish and caused human illness. The outbreaks are thought to result from the contamination of streams, reservoirs, and estuaries by animal manure organisms and nutrients, mainly nitrogen (N) and P. The greatest potential for accelerated eutrophication of surface waters usually occurs in watersheds with intensive animal production. Confined animal feeding operations have become targets of stringent discharge containment regulations. Runoff from livestock pens, poorly designed or maintained manure storage areas, and fields where manure is repeatedly applied presents potential environmental hazards to the overall watershed. The
over-enrichment of receiving waters with mineral nutrients leads to excessive growth of autotrophs, especially algae and cyanobacteria. The increased microflora utilizes dissolved oxygen, which results in hypoxia or anoxia. The lack of oxygen causes the loss of aquatic animals and release of many materials normally bound to bottom sediments including the various forms of P. Phosphorus is most often the element limiting eutrophication, since many algae are able to obtain N from the atmosphere. Consequently, the only definitive method for controlling algal blooms and eutrophication is to minimize agricultural P inputs to surface waters.
3. How does it relate to the National Program(s) and National Component(s)?
The project specifically addresses research gaps identified in National Program 206 "Manure and Byproduct Utilization-Nutrient Component" (Problem Areas 1, 2, 3, and 4). The multi-disciplinary effort will provide a basic understanding of manure chemistry and the integration of that knowledge into decision support tools and environmentally sound manure management practices on the farm.
4. What were the most significant accomplishments this past year?
A. Single most significant accomplishment during FY-2001 year: A major fraction of the total P in manure particulates is organic in nature. Research results showed that the biological transformations and release of inorganic P from phytate-P, the key form of organic P in animal feed and manure, were significantly modified by the nature of cation present. Therefore, the differential stability of organic phosphates may result in differences in the biological release of inorganic P under varying manure storage and soil environments. B. Other Significant Accomplishment(s), if any: Research using near- and mid-infrared spectroscopy demonstrated that, as presently used, these techniques do not offer promise as a means for rapid and accurate determination of manure P. Our research showed that raw poultry manure contained high levels of soluble P, averaging about 2034 ppm or 4 lb of soluble P/t. The fractionation of poultry manure showed that another 60% was released by mineral acid and
base extractants. These fractions were likely associated with mineral phosphates, such as iron and calcium phosphates. The residual fraction that was remained after exhaustive extraction was large and deemed to be non-mineral and amounted to about 30% of the total P of untreated manure. To maintain the option of manure application on croplands, P immobilization amendments are used to reduce the excessive levels of soluble reactive manure P and can play key role in risk minimization strategies for land application of manure. However, the changes in these manure P chemical forms induced by water-treatment residuals and other mineral by-products are largely undefined. The reaction of aluminum and iron from water-treatment residuals or industrial processing by-products with manure P, especially iron, reduces manure soluble P by enhancing the precipitation of more insoluble mineral phosphates. In combination with composting to stabilize manure N, the amendments reduce potential
discharge and movement of manure P in the environment. In liquid manure, the aggregation of particulates promotes their concentration into a small volume along with them organic manure nutrients. Research on P and particulate removal from dairy manure showed that the particulate separation process is a complex function of manure characteristics, and the processes of coagulation, flotation, and sedimentation to isolate the solid phase and clarify the liquid wastewater. The complexity of the aggregation reaction was evident in single-chemical use cases. Multiple mechanisms were operational in the concentration range of polyacrylamide polymers and P immobilizing amendments used. Synergistic effects of combining cationic polyacrylamide polymers and P immobilizing agents existed and may be hard to predict. But these combinations improved solid separation in dairy manure of total suspended solids between 3 and 10% and reduced particulate and soluble P. The P immobilizing amendments
worked as they did in solid poultry and cattle manure in our previous studies. Wastewater quality was improved, thereby allowing water reuse and conservation in manure management practices of confined animal feeding operations (CAFO). C. Significant Accomplishments/Activities that support special target populations: Participated in 2000 public field days to illustrate current best manure management practices for dairy operations. Communicated potential soluble P reduction strategies to the NE Dairy Producers Association and the Zero Waste Alliance. Provided scientific information and technical support to the USDA-Natural Resource Conservation Service on the issue of managing excessive levels of phosphorus on lands where repeated applications of animal manure were made. D. Progress Report: Near infrared diffuse reflectance spectroscopic (NIRS) analyses of over 200 samples of poultry manure showed that NIRS technique accurately determine nitrogen (ammonium, organic, and total N) and
moisture content of manure using spectral data in the 1100 to 2498 nm range. However, the determination of minerals was not satisfactory due to the lack of spectral absorptions for minerals in the NIR region. Weak correlation of observed and predicted potassium and calcium contents were found. None was found for P, or Mg, Zn, etc . The predictability of mineral content was indirect and dependent upon organic components that were associated with the mineral of interest. Offsite land application of animal manure is the major avenue for disposing of the large volume of manure produced by concentrated animal feeding operations. Manure still contains large quantities of plant nutrients in both inorganic and organic forms in partial states of decomposition. Our research showed that raw poultry manure contained high levels of soluble P, averaging 2034 ppm. The fractionation of poultry manure showed that another 60% was released by mineral acid and base extractants. These fractions are
likely associated with mineral phosphates, such as iron and calcium phosphates. The residual fraction that was remained after exhaustive extraction was deemed to be non- mineral and amounted to about 30% of the total P of untreated manure. To maintain the option of manure application on croplands, the manure soluble reactive N and P levels must be reduced to bring the N to P ratio to correspond more with that needed for crop growth. Phosphorus immobilization amendments are used to reduce the excessive levels of dissolved levels and can play key role in risk minimization strategies for land application of manure. The immobilization approach decreases an important P source term in risk indexing and the potential threat of P runoff and environmental transport. However, the changes in these manure P chemical forms induced by water-treatment residuals and other mineral by-products are largely undefined. We found that differential affinity for phosphate-P existed between aluminum- and
iron-rich by- products used to reduce soluble reactive P in animal manure. Unlike metal salts reacting with soluble phosphate-P when amended to raw manure to immobilize phosphate, amorphous aluminum oxides in water- treatment residuals are not likely to lower the mixture pH that would lower the P immobilization efficiency of aluminum salts. On a 1 to 1 cation-to-P basis, the by-product rich in iron was more efficient in immobilizing soluble P enhancing the formation of iron phosphates, even at the expense of any existing aluminum phosphates in treated manure. Therefore, the choice of immobilization agents affected the eventual stability of immobilized P forms and should be taken into consideration when designing manure treatment methods. The use of relatively inexpensive industrial and municipal by-products containing aluminum and iron to reduce soluble P in animal manure before land application is a practical manure management practice and a promising component of an overall
non-point source pollution prevention strategy. In combination with composting to stabilize manure N, mineral by-products can reduce the environmental risks of recycling of manure back into agronomic production.
5. Describe the major accomplishments over the life of the project including their predicted or actual impact.
Research showed that manure soluble P readily reacted with calcium, aluminum, and iron from metal-rich water treatment residuals and industrial by-products before land application to minimize potential P transport and over-enrichment of nearby surface waters. Enhancing particulate aggregation in slurry manure concentrated particulate P in a small volume of solid manure, though the narrow N to P nutrient ratio may still exist in that solid fraction. Liquid manure treatment with combination of polyacrylamide polymers and P immobilizing amendments clarified and improved wastewater quality, thereby allowing water reuse and conservation in manure management practices of confined animal feeding operations. Research using near- and mid-infrared spectroscopy demonstrated that, as presently used, these techniques do not offer promise as a means for rapid and accurate determination of manure P.
6. What do you expect to accomplish, year by year, over the next 3 years?
Year 1: During the next year, an analytical survey of P forms will be performed for dairy manure, and preliminary investigations undertaken for beef and swine manure. Nuclear magnetic resonance spectroscopic procedures will be used to determine the forms of P in 107 dairy manure samples from the North Atlantic region. In addition, a study will be undertaken using the data already available on reflectometer, hydrometer, near- and mid-infrared spectroscopy to test their applicability to P analysis. The conditions and mechanisms of decomposition of organic P forms will be studied to accurately determine the release of inorganic reactive P in wastewater, manure, and manured field soils. Year 2: Efforts will be made to develop other quick test procedures for determining manure P, assuming that efforts with infrared spectroscopy are not successful. Studies of transformations of organic P, extraction methods and separation of metabolites in manure and manured soil studies will be
conducted. Laboratory-scale manure processing techniques will be developed for fast and reproducible liquid-solid separation and nutrient distribution. Year 3: Studies of organic P mineralization and extraction methodology will be completed to identify process control factors. Initial data on relative efficacy of chemical approach will be summarized and forms the basis for developing benchtop-scale treatment and use of organic polymers and mineral by-products in solid coagulation and soluble P reduction in wastewater.
7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints if known, to the adoption & durability of the technology product?
Preliminary results have been reported at field days and producer meetings such as the 1999 Chesapeake Bay Day and the 2000 Sustainable Agriculture Field Day at BARC. Technical presentations were made at professional meetings of the American Society of Agronomy, the Soil Science Society of America and workshops of the Southern Conservation Tillage Conference and Southern Extension Research Activity - Information Exchange Group 17 (SERA-17). Presented dairy manure P fractionation/ partitioning and P recovery approaches to representatives of the Zero Waste Alliance and Pacific Gas & Electric.
8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below)
Chemical treatment for particulate aggregation and P reduction in dairy manure. Presented at the meeting of SERA-Information Exchange Group 17, State College, PA. July 20, 2001.
Impacts
(N/A)
Publications
- Reeves III, J.B. Near-Infrared Diffuse Reflectance Spectroscopy for the Analysis of Poultry Manure. Journal of Agricultural and Food Chemistry. 2001. v. 49. p. 2193-2197.
- Dao, T.H., Sikora, L.J., Hamasaki, J., Chaney, R.L. Mineral By-products and Composting Effects on Manure Phosphorus Extractability. Agronomy Abstracts. 2000. p. 397.
- Schwartz, R.C., Dao, T.H. Soil Phosphorus Levels Following Manure and Compost Applications within a Wheat-Sorghum-Fallow Rotation. Agronomy Abstracts. 2000. p. 287.
- Cavigelli, M., Teasdale, J., Dao, T.H., Radhakrishnan, J., Buyer, J.E., Nichols, K.A., Liang, S., Shuey, C. The USDA-ARS Farming Systems Project: Developing sustainable cropping systems for the Mid-Atlantic region. Agronomy Abstracts. 2000. p. 83.
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Progress 10/01/99 to 09/30/00
Outputs
1. What major problem or issue is being resolved and how are you resolving it?
High dietary P excretion by livestock, uncontrolled nutrient discharges from animal feeding facilities and manure storage areas, and repeated land application of manure can result in excessive P concentrations in soils and losses of P to the environment. Non-point sources of agricultural P, along with other manure components can cause accelerated eutrophication and anoxia in nearby surface waters and pose potential risks to the overall watershed, airshed, and human health. To address this nationwide problem we need to understand P chemistry, transformation processes, and potential methods for controlling manure P discharges and movement in the environment. Detailed investigations will be conducted to determine the inorganic and organic forms of P present in different manures and their relative bioavailability. Relative efficacy of key chemical stabilization and liquid and solid phase separation approaches will be evaluated to address excessive soluble reactive P levels in manure
under commonly used handling, storage, and application systems. Methodology will include analysis of intact manure samples and sequential extraction and analysis of extracts by pyrolysis-GC-MS, mid-infrared spectroscopy, 31P-NMR, and HPLC.
2. How serious is the problem? Why does it matter?
The research project addresses a major environmental issue facing the US livestock feeding industry and the results will help farmers more efficiently manage their animal manure and comply with comprehensive nutrient management plans in threatened watersheds across the country and near major estuaries. Outbreaks of Escherichia coli and Pfiesteria which have killed fish and caused human illness are thought to result from the pollution of streams, reservoirs, and estuaries by animal manure organisms and nutrients, mainly nitrogen and phosphorus. The greatest potential for accelerated eutrophication of surface waters usually occurs in watersheds with intensive animal production. Confined animal feeding operations have become targets of stringent discharge containment regulations. Runoff from livestock pens, poorly designed or maintained manure storage areas, and fields where manure is applied presents potential environmental hazards to the overall watershed. Elevated P and N levels
often are associated to algal blooms and accelerated eutrophication of lakes and streams. The over-enrichment of receiving waters with mineral nutrients leads to excessive growth of autotrophs, especially algae and cyanobacteria. The increased microflora utilizes dissolved oxygen, which results in hypoxia or anoxia. The lack of oxygen causes the loss of aquatic animals and release of many materials normally bound to bottom sediments including the various forms of P. Phosphorus is most often the element limiting eutrophication, since many algae are able to obtain N from the atmosphere. Consequently, the only definitive method for controlling algal blooms and eutrophication is to minimize P loading to surface waters.
3. How does it relate to the National Program(s) and National Component(s)?
The project specifically addresses research gaps identified in National Program 206 "Manure and Byproduct Utilization-Nutrient Component" (Problem Areas 1, 2, 3, and 4). The multi- disciplinary effort will provide a basic understanding of manure chemistry and the integration of that knowledge into decision support tools and environmentally sound manure management practices on the farm.
4. What were the most significant accomplishments this past year?
A. Single Most Significant Accomplishment during FY 2000 year: Initial efforts have been devoted to the development of specific multi-disciplinary studies of manure P distribution and the compilation of laboratory techniques to reduce soluble P in manure. Research on metal affinity for manure P indicated that an iron-rich amendment was generally more effective at reducing water-soluble P fraction of treated manure than an Al-rich water treatment residual. B. Other Significant Accomplishment(s), if any: Preliminary studies of the effects of organic polymers on liquid- solid separation of slurried manure indicated that they are effective in concentrating solids and improving the partitioning and recovery of manure phosphorus when used in conjunction with mineral P sequestering agents. Starch source was found to affect phosphorus availability for dairy cows. C. Significant Accomplishments/Activities that Support Special Target Populations: We provided scientific information and
technical support to the USDA-Natural Resource Conservation Service on the issue of managing excessive levels of phosphorus on lands where repeated applications of animal manure were made. D. Progress Report: Shifts in manure P chemical forms induced by water-treatment residuals and industrial mineral by-products are largely untested. We found that differential affinity for phosphate-P existed between the two metal-rich by-products used to reduce soluble reactive P in animal manure. Fe-rich by-product was generally more effective at reducing the water-soluble P fraction of the untreated manure then an Al-water treatment residual, sequestering P in more insoluble metal phosphates. Composting did not reduce the sequestration efficacy of the mineral by- products and could potentially produce a synergistic effect that would increase the efficacy and benefits of P sequestering agents.
5. Describe the major accomplishments over the life of the project including their predicted or actual impact.
Research showed that aluminum and iron-rich water treatment residuals and industrial by-products can be used to reduce soluble reactive phosphorus in animal manure prior to land application and minimize phosphorus movement and over-enrichment of nearby surface waters.
6. What do you expect to accomplish, year by year, over the next 3 years?
Year 1: During the next year, an analytical survey of P forms will be performed for dairy manure, and preliminary investigations undertaken for beef and swine manure. In addition, a study will be undertaken using the data already available on reflectometer, hydrometer, near- and mid-infrared spectroscopy to test their applicability to P analysis. Year 2: Studies of transformations of organic P, extraction methods and separation of metabolites in manure studies will be conducted. Laboratory-scale manure processing techniques will be developed for fast and reproducible liquid-solid separation and nutrient redistribution. Year 3: Manure samples will be obtained from controlled studies and farms to determine the effects of diet, storage, etc. on forms of manure P. Studies of P mineralization in manure and extraction methodology will be completed to identify process control factors. Initial data on relative efficacy of mechanical approach will be summarized and forms the basis for
follow-up treatment and use of organic polymers and mineral by-products in liquid-solid separation.
7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints if known, to the adoption & durability of the technology product?
Preliminary results have been reported at field days and producer meetings such as the 1999 Chesapeake Bay Day and the 2000 Sustainable Agriculture Field Day at BARC. Technical presentations were made at professional meetings and workshops.
8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below)
Processing animal manure to optimize nitrogen to phosphorus ratio and reduce offsite discharges and environmental impact of manure nutrients. Dao, T. H., Lefcourt, A., Sikora, L., and Cavigelli, M., Presented at the Chesapeake Bay Day, BARC, Beltsville, MD. October 1999. Animal Environmental Chamber: Ammonia and Odor Control Related to Concentrated Animal Feeding Operations. Lefcourt, A., Dao, T. H., L. McConnell, L., Meisinger, J., Millner, P., Reeves, J., and Van Kessel, J. S. Presented at the Chesapeake Bay Day, BARC, Beltsville, MD. October 1999. Manure Management: The Environment and Food Safety. Presented at the Sustainable Agriculture Field Day, BARC, Beltsville, MD. August 8, 2000.
Impacts
(N/A)
Publications
- Dao, T.H. Assessing phosphate flux and retention by flow displacement. Agronomy Abstracts. 1999. Abstract p. 340.
- Guyton, A.D., Knowlton, K.F., Casper, D.P., Glenn, B.P., Wilkerson, V.A. Starch source affects phosphorus digestion and excretion by lactating dairy cows. Journal of Animal Science. 2000. 78(Suppl. 1):Abstract p. 288.
- Dao, T.H. Co-amendments to modify phosphorus extractability and N:P ratio in feedlot manure and composted manure. Journal of Environmental Quality. 1999. v. 28. p. 1114-1121.
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