DEVELOPING ANALYTICAL AND MANAGEMENT STRATEGIES TO IMPROVE CROP UTILIZATION OF .... AND REDUCE LOSSES TO THE ENVIRONMENT

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	0110	2000	50%
403	3299	2020	20%
102	3399	2000	10%
403	3499	2020	20%

Progress 04/03/10 to 04/02/15

Outputs
Progress Report Objectives (from AD-416): 1. Develop practices to enhance the beneficial use of manure nutrients and reduce offsite losses through management of the environmental fate and transport of organic carbon, nitrogen, and phosphorus derived from poultry, dairy, and beef cattle manures. 2. Develop integrated crop, soil, and dairy/beef/poultry manure management strategies to improve nutrient utilization and minimize leaching and runoff losses. Approach (from AD-416): Real-time tools for rapid C, N, and P detection and multi-element analysis of manures, soils, and crops will be evaluated and adapted to develop precision nutrient management practices under changing soil microenvironment and weather conditions. Process knowledge affecting C, N, and P transformations and detection will be gained to establish databases and develop algorithms to assist in the management of bionutrient mineralization and availability in conservation cropping systems. Nutrients used in production agriculture, in particular manure nutrients, continue to cause the degradation of natural ecosystems. Decomposition of manure and other organic nutrient sources and the release of nutrient contained within are tied to the conversion of complex forms of manure carbon, phosphorus, and nitrogen into soluble labile forms. ARS scientists found a clear linkage between inorganic and organic phosphorus conversion to the manure carbon-to-phosphorus composition. The results suggested that on-farm manure handling and storage conditions should be managed to minimize this conversion, by adjusting the carbon content in stored slurries, and lower risks of high levels of mobile phosphate to runoff when these manures are land-applied. In the field, managing declining use-efficiency of added phosphorus is related to knowing well the nature of inorganic and organic chemical forms that are present and in what proportion they occur in the soil. In long-term field studies, a linkage exists between zones of phosphorus accumulation, manure composition, and soil biological properties for the last 18 years. Applying manure at a replacement rate equal to that removed by crops did not prevent the accumulation of available and total phosphorus in these soils. There were changes in the ratio of inorganic- to-organic forms, and their uneven distribution across the field during manure spreading modified soil biological properties and risks of losses at the soil surface. Knowing only water-soluble and total phosphorus content as currently required in management of total contaminant loading to nearby water bodies is inadequate for assessing phosphorus availability or for predicting losses and risk of edge-of-field runoff. The variability in the ratio of phosphorus forms in the soil persisted over the years, and this phenomenon distorts the picture of phosphorus availability across the field. Therefore, the formulation of phosphorus recommendations for future growing seasons is biased and inaccurate when an average value of field phosphorus is used in routine soil testing for available phosphorus. In a related effort, to minimize the inherent variability of animal manure composition in order to achieve a more predictable fertilizer, broiler and layer manure ash is a valuable P source following the combustion of manure for bioenergy production. The effects of the residual ashes on growth and uptake of phosphorus and arsenic in corn, wheat, and alfalfa were compared to those of calcium phosphate, a mineral fertilizer. Corn dry matter yield with calcium phosphate, was higher than that found with the manure ash additions. This suggested a trade-off between stabilization and availability to plants as the ash phosphorus behave as a form of low-grade rock phosphate ore. Improvements in real-time detection and management technologies were also studied to increase recovery and use-efficiency of applied nutrients. Managing declining nutrient use efficiency in crop production has been a global priority to maintain high agricultural productivity with non- renewable nutrient resources such as phosphorus. Rapid testing methods can increase the number of repeated measurements of soil nutrients and improve the accuracy of estimating the rate of phosphorus needed for optimal crop growth and yield. ARS scientists developed a computational relationship between phosphorus measured by X-ray fluorescence and plant- available phosphorus forms to allow an accurate description of their geographic distribution. Distinct management zones were identified for more precise placement of additional phosphorus needed for optimal crop growth. The findings documented the direct element-specific analysis by X- ray fluorescence and its high sample throughput make the technology an important component of a new nutrient sensing approach. The technology will allow farmers to sustainably manage phosphorus, and other crop nutrients such as potassium, calcium, or chloride in production fields, based on their location-specific variations in the soil. Whether it is bio-energy or improving agricultural interest in restoring the health of degraded soil resources, there is increased interest in biochars made from agricultural by-products to store carbon in soil and spectroscopic techniques for assessing their composition. Differences exist between analytical approaches and the direction of future development of relevant instrumentation when the needs of these two economic sectors are considered. Near-infrared spectroscopy, used to determine the composition of numerous agricultural products, is an effective method for determining biochars' properties and relative efficacy. Project scientists obtained biochar spectra with a scanning monochromator that was far superior as it collects more spectral data at a lower resolution to improve their interpretation. Mid-infrared spectroscopy has also been used to rapidly determine fiber components and protein in forages and grains at reduced cost and increased speed. The same components are of interest to the optimization of processes for industrial-scale production of biofuel. Practical and technical differences exist between the two sectors� needs that will dictate how near-infrared and mid-infrared technologies are developed for the biofuel sector. Direct analysis of fiber components and possibly new spectroscopic methods will be needed. These issues will become increasingly important when feedstocks shift away from starch for producing ethanol or plant oil for producing biodiesel to cellulosics. Among strategies developed for improving N recovery in agriculture and reduce losses to the environment, crop canopy monitoring proved valuable in evaluating N-use efficiency. Crop monitoring techniques such as canopy reflectance of visible and near infrared light can be used to forecast fields likely to be under drought and potentially have high residual nitrate. Early identification can provide opportunities for establishing cover crops to these sites and reduce nitrate leaching during the subsequent water-recharge season. Improved use-efficiency is also related to management of added starter nitrogen during the establishment of a row crop. Currently, starter recommendations commonly use a fixed rate without adjusting for fall residual nitrogen. Winter wheat yield response to 65 starter-nitrogen products showed a decrease as fall soil nitrate increased, and that these data, combined with fertilizer cost and commodity price information, could estimate the point where soil residual nitrate is likely to be sufficient for winter wheat establishment. This provides a method for identifying nitrogen sufficient sites and improves nitrogen use efficiency for winter wheat while concurrently reducing potential nitrate losses. To improve nitrogen use efficiency, project scientists focused on minimizing major loss processes, that is, reducing ammonia volatilization and nitrogen leaching losses. Ammonia volatilization from surface- applied poultry litter can account for one-fourth to one-half of the litter�s ammonia nitrogen. Studies showed that compared to surface- applied litter, ammonia volatilization decreased an average of 67% by light disking, and decreased 88% when litter was applied below the soil surface. These results demonstrate that subsurface injection of dry poultry litter can minimize ammonia loss. However, injection can create anaerobic soil conditions that favor denitrification or loss as N2 gas (a benign gas) or as nitrous oxide (a greenhouse gas). Improved crop utilization of the N conserved is commonly observed following injection, but this benefit can be minimal, which is consistent with greater denitrification losses. Thus, nitrogen management strategies for no-till winter wheat in the mid-Atlantic must reduce nitrate leaching while maintaining economic production. Lysimeters, or columns of minimally disturbed soils extracted from the field, are valuable tools for comparing the effects of nitrogen management practices on water quality. ARS scientists at Beltsville improved procedures for excavation, encasement, transportation, and field-testing of large undisturbed soil cores. No-tillage lysimeters were found to have higher infiltration rates than those excavated from fields receiving annual moldboard-plowing, which was attributed to more inter-connected large pores in columns of no-till soil. Utilizing lysimeters, ARS scientists showed that during the fall establishment season, no-tillage produced significantly higher drainage volumes and nitrate leaching losses compared to plow-tillage. Limiting fall-N applications, and timing spring-N applications to coincide with wheat N demand can substantially reduce leaching losses. Accomplishments 01 Overestimating phosphorus needs of crops contributed to large surpluses in soil. An alternative method for determining bioactive phosphorus was developed because current soil testing procedures failed to account for the presence and size of the organic phosphorus fraction in organic sources of crop nutrients. The oversupply has long-lived impact and contributes to elevated levels 12 or more years later, even after readjustment. Users of this research include organic farmers, researchers, NRCS, nutrient managers, and policy makers. 02 Nitrogen management strategies for no-till winter wheat in the mid- Atlantic must maintain economic production and reduce nitrate leaching. No-tillage produced significantly higher drainage volumes and nitrate leaching losses compared to plow-tillage in a four-year lysimeter study. Limiting fall-N applications and timing spring-N applications to coincide with wheat N demand reduced leaching losses. Customer/Users of this research include researchers and educators, NRCS, and Extension nutrient managers, state and local environmental staffers, and private industry fertilizer and nutrition managers.

Impacts
(N/A)

Publications

Meisinger, J.J., Palmer, R.J., Timlin, D.J. 2015. Effects of tillage practices on drainage and nitrate leaching from winter wheat. Soil and Tillage Research. 151:18-27.
Shelton, D.R., Pachepsky, Y.A., Kiefer, L., Blaustein, R.A., McCarty, G.W., Dao, T.H. 2014. Response of coliform populations in streambed sediment and water column to changes in nutrient concentrations in water. Water Research. 59:316-324.
Dao, T.H., Schomberg, H.H., Cavigelli, M.A. 2014. Tillage and rotational effects on exchangeable and enzyme-labile phosphorus forms in conventional and organic cropping systems. Nutrient Cycling in Agroecosystems. 101:153- 165.

Progress 10/01/13 to 09/30/14

Outputs
Progress Report Objectives (from AD-416): 1. Develop practices to enhance the beneficial use of manure nutrients and reduce offsite losses through management of the environmental fate and transport of organic carbon, nitrogen, and phosphorus derived from poultry, dairy, and beef cattle manures. 2. Develop integrated crop, soil, and dairy/beef/poultry manure management strategies to improve nutrient utilization and minimize leaching and runoff losses. Approach (from AD-416): Real-time tools for rapid C, N, and P detection and multi-element analysis of manures, soils, and crops will be evaluated and adapted to develop precision nutrient management practices under changing soil microenvironment and weather conditions. Process knowledge affecting C, N, and P transformations and detection will be gained to establish databases and develop algorithms to assist in the management of bionutrient mineralization and availability in conservation cropping systems. An accurate and timely measure of available phosphorus (P) in the soil and phosphorus-containing soil amendments is often needed as excessive loading of agricultural soils with phosphorus-enriched animal manure often increases risks to surface waters associated with elevated concentrations of dissolved and particulate phosphorus in runoff. Thus, knowing nutrient contents of soil and crops, in real time, allows timely management adjustments in response to changes in nutrient availability during the growing season. A portable X-ray fluorescence method was evaluated for its nutrient-specific ability to differentiate variations in phosphorus in soil and in crop canopy. Spectral scans made during the seedling stages of growth revealed nutrient profiles that were correlated to soil P composition and manure application rates. The field evaluation studies showed that a separation of 12.5 lbs. per acre or greater in soil phosphorus levels was visible and recorded as distinct foliar phosphorus levels. On-the-spot analysis and the production of a spatial map of crop phosphorus status showed promise in managing phosphorus variability that was directly linked to actual crop phosphorus needs. The capability offers promise in site-specific precision management of crop nutrients and reduce risks of environmental contamination from recycling manure nutrients on agricultural fields in the Chesapeake Bay. Excessive rates of nitrogen from manure or fertilizer can contribute to high levels of residual soil nitrate after corn crop. This residual nitrate can be readily transported into water resources during the fall and spring water recharge season in the humid East. Residual nitrate is highly variable from site to site and year to year, which prompted a series of studies to evaluate simple techniques for identifying sites likely to have high soil nitrate in the fall. Lower yields resulting from drought was found to be a major factor linked to high residual nitrate. A simple approach to identify sites likely to have high residual nitrate is to calculate the difference between actual corn yields and the expected corn yields, which showed that nitrogen applied in excess of crop needs is directly related to fall residual nitrate. An early identification of high residual nitrate sites can provide opportunities for targeting cover crops, which can reduce nitrate losses to water resources during the subsequent water recharge season. Cover crops can provide a valuable service by conserving residual nitrogen after corn. The recovery of isotope-labeled fertilizer was used to directly compare the ability of rye, wheat, and native weeds to recover residual N applied to a preceding corn silage crop. Work has been completed on the field phase of this study that collected and processed soil and crop samples in the early winter, early spring, and late spring over three years. These samples are currently being analyzed to determine the changes in soil nitrate and the uptake of labeled N by the winter crops. This study will quantify the effectiveness of cover crop management strategies for capturing residual nitrate, which will reduce nitrate losses to ground water in the Chesapeake Bay Watershed. Significant Activities that Support Special Target Populations: Two high school interns from under-represented minorities in science were hosted during FY14 to work and document their science projects on multi- elemental analysis of soil samples using x-ray fluorescence and study the distribution and spatial structure of residual phosphorus in fields amended with animal manure. Interns acquired basic practical research skills to partially fulfill their community service and graduation requirements. Accomplishments 01 Ammonia volatilization from surface-applied poultry litter can account for one-fourth to one-half of the litter�s ammonia nitrogen. The results from a series of wind tunnel studies were published that evaluated methods to reduce ammonia loss, yet retain high surface residue cover for erosion control. The data showed that compared to surface-applied litter, ammonia volatilization decreased an average of 67% by light disking, and decreased 88% when litter was applied below the soil surface using the prototype applicator developed by ARS collaborators in Arkansas. These results demonstrate that subsurface injection of dry poultry litter can minimize ammonia loss, thus conserving nitrogen for row crops and reducing potential nitrogen losses to the environment. 02 Managing starter nitrogen for winter wheat is difficult because fall soil nitrate is highly variable and because starter nitrogen can be leached into groundwater during the winter water-recharge season. Wheat starter nitrogen recommendations commonly use a fixed rate without adjusting for fall residual nitrogen. A series of 65 starter- nitrogen winter wheat yield response studies were conducted in Maryland to estimate the fall soil nitrate concentration that is sufficient for establishing wheat, and that is cost effective. A subset of studies also measured soil nitrate loss below two feet during the winter season and evaluated over-winter bromide loss as a potential index for nitrate leaching. Results showed that using winter rainfall divided by the site�s available soil water-holding capacity provided a good index for nitrate leaching. These studies also showed that wheat yield response to starter nitrogen decreased as fall soil nitrate increased, and that these data, combined with fertilizer cost and price of wheat information, could estimate the point where soil residual nitrate is likely to be sufficient for establishing winter wheat. This study provide a method for nutrient managers, producers, and policy makers to identify nitrogen-sufficient sites and improve nitrogen use efficiency for winter wheat while concurrently reducing potential nitrate losses to receiving waters.

Impacts
(N/A)

Publications

Guber, A., Pachepsky, Y.A., Dao, T.H., Shelton, D.R., Sadeghi, A.M. 2013. Evaluating manure release parameters for nonpoint contaminant transport model KINEROS2/STWIR. Ecological Modeling. 263:126-138.
Pote, D.H., Meisinger, J.J. 2014. Effect of poultry litter application method on ammonia volatilization from a conservation tillage system. Journal of Soil and Water Conservation. 69(1):17-25.
Forrestal, P.J., Meisinger, J.J., Kratochvil, R.J. 2014. Winter wheat starter nitrogen management: a preplant soil nitrate test and site specific nitrogen loss potential. Soil Science Society of America Journal. 78(3):1021-1034.
Dao, T.H. 2014. Landscape-scale geographic variations in microbial indices and labile phosphorus in Hapludults. Biology and Fertility of Soils. 50(1) :155-167.
Shelton, D.R., Kiefer, L., Pachepsky, Y.A., Martinez, G., Mccarty, G.W., Dao, T.H. 2013. Comparison of microbial quality of irrigation water delivered in aluminum and PVC pipes. Agricultural Water Management. 129:145�151.

Progress 10/01/12 to 09/30/13

Outputs
Progress Report Objectives (from AD-416): 1. Develop practices to enhance the beneficial use of manure nutrients and reduce offsite losses through management of the environmental fate and transport of organic carbon, nitrogen, and phosphorus derived from poultry, dairy, and beef cattle manures. 2. Develop integrated crop, soil, and dairy/beef/poultry manure management strategies to improve nutrient utilization and minimize leaching and runoff losses. Approach (from AD-416): Real-time tools for rapid C, N, and P detection and multi-element analysis of manures, soils, and crops will be evaluated and adapted to develop precision nutrient management practices under changing soil microenvironment and weather conditions. Process knowledge affecting C, N, and P transformations and detection will be gained to establish databases and develop algorithms to assist in the management of bionutrient mineralization and availability in conservation cropping systems. Knowing nutrient contents of soil and crops, as close to real time as possible, allows timely management adjustments in response to changes in nutrient availability during the growing season. An X-ray fluorescence method was evaluated for its nutrient-specific ability to differentiate variations in phosphorus in crop seedlings. While irradiating a sample with incident X-rays, their intensity weaken as function of radiation energy and nutrient elements present in the sample. Light elements that include essential plant nutrients such as phosphorus, potassium, sulfur, etc� emit fluorescence radiation of long wavelength and low-energy. This resulted in low analytical sensitivity. In addition, these characteristic radiations were further attenuated by water content of fresh leaves. Calibrations for crop type and leaf characteristics were made to derive leaf nutrient composition, and for making comparison under varied field conditions. The adjustment and a high throughput screening of a crop canopy allowed a greater number of analyses under actual growing conditions across a large field. The ability of making on-the-spot analysis and the production of a spatial map of crop phosphorus status offer promise in managing phosphorus variability that are directly linked to actual crop phosphorus needs in order to reduce risks of environmental contamination from recycling manure nutrients on agricultural fields. Ammonia volatilization from surface-applied poultry litter can account for one-fourth to one-half of the litter�s ammonia nitrogen. A series of wind tunnel studies were completed that evaluated methods to reduce ammonia loss, yet retain high surface residue cover for erosion control. These studies were the basis for a manuscript that has been accepted for publication in a peer reviewed journal, but the paper has not been assigned an issue or pagination. The data showed that compared to surface- applied litter, ammonia volatilization decreased an average of 67% by light disking, and decreased 88% when litter was applied below the soil surface using the prototype applicator developed by ARS collaborators in Arkansas. These results show that subsurface injection of dry poultry litter can minimize ammonia loss, thus conserving nitrogen for row crops and reducing potential nitrogen losses to the environment. Cover crops can provide a valuable service by conserving residual nitrogen after corn. The recovery of isotope-labeled fertilizer was used to directly compare the ability of rye, wheat, and native weeds to recover residual N applied to a preceding corn-silage crop. The field phase of this study was completed, which involved collection of soil and crop samples in the early winter, early spring, and late spring. These samples are being analyzed for labeled N to follow changes in soil nitrate and the uptake of labeled N by the winter crops. This study will quantify the effectiveness of cover crop management strategies for capturing residual nitrate, which will reduce nitrate losses to ground water and the Chesapeake Bay. Significant Activities that Support Special Target Populations: ARS scientists made key presentations on x-ray spectroscopic analysis of phosphorus in soil and recommendations for managing landscape-scale heterogeneity of soil microbial indices to a multi-disciplinary audience at the 2012 EuroSoil Conference held in Bari, Italy. Over 500 scientists and specialists in nutrient and environmental management attended the workshop. An ARS scientist is contributing to updating the Chesapeake Bay Watershed Model by chairing an 18-member Cover Crop Expert Panel that is charged with revising the nitrogen, phosphorus, and sediment reduction efficiencies for cover crops within the Bay Model. These reduction efficiencies, combined with reported acreages of cover crop by species, provide the mechanisms that producers use to claim nutrient reductions credits for planting cover crops. Updating the cover crop nutrient reduction credits will contribute to further expansion of the use of covers within the Chesapeake Bay Watershed. An ARS scientist is a federal representative on the Chesapeake Bay Science and Technical Advisory Committee that is composed of 30 members representing marine scientists, hydrologists, soil scientists, agronomists, modelers, economists, waste treatment plant operators, atmospheric scientists, and social scientists from Land Grant Colleges, State, and private organizations. The committee met quarterly to provide technical reviews and advice on a variety of issues. For example: technical evaluations of strategies to restore the Bay (e.g. use of cover crops, methods to track improvements in the Bay, etc.); identification of future important issues facing the Bay (e.g. global climate change, impact of mining by hydraulic fracturing, etc.); and enhancing program delivery (e.g. develop a Bay Modeling Lab., promulgation of publications). Local watershed planners within the Chesapeake Bay are responsible for developing Watershed Implementation Plans (WIPs) that list the intended management practices to reduce nutrient losses to the Bay. Implementing agricultural best management practices usually provide a majority of the planned nutrient reductions. An ARS scientist made two keynote presentations on nitrogen management tools to reduce nitrate and ammonia losses to the Bay, and authored the final Workshop report (http://www. chesapeake.org/pubs/295_Meisinger2012.pdf). The presentations and final report reviewed principles and evaluated best management practices for reducing nitrogen losses to the Bay, which occur through both water and atmospheric pathways. The workshop was attended by about 300 people from local planning teams, farmers, nutrient management consultants, fertilizer and animal industries, and State environmental and agricultural staffers. The presentations and the Workshop report provide a state-of-the-art update of nutrient best management practices available to the WIPs for developing their watershed implementation plans. Mentored two high school interns and developed students� independent science projects on multi-elemental analysis of plant and soil samples using x-ray fluorescence as affected by plant architecture, and selected soil physical characteristics. Helped the interns acquire basic practical research skills to partially fulfill their community service and graduation requirements of the 2012-13 school year. Accomplishments 01 Use-efficiency of phosphorus in agricultural fields is declining. Managing the decline is to know well the type and proportion of inorganic and organic phosphorus forms present in soil. An ARS scientist implemented a long-term study to determine whether a linkage exists between zones of phosphorus accumulation in a large field amended with dairy manure. Results showed that applying manure at a replacement rate equal to that removed by crops did not prevent overall accumulation of available and total phosphorus in these soils. Current comprehensive nutrient management plans involving efforts to control land application of animal manure by limiting phosphorus input rates to that removed by crops may be a pragmatic approach but an ineffective one, given weaknesses of current field management practices. The distribution of phosphorus forms in the soil is very uneven after 16 annual applications of dairy slurry. There are changes in the ratio of inorganic-to-organic forms and their uneven distribution across the field modified biological properties, microbial ecology, transformations between phosphorus forms in the root zone, and risks of losses at the soil surface. Knowing only water-soluble and total phosphorus content as currently required in management of total contaminant loading to nearby water bodies is inadequate for assessing phosphorus availability or for predicting losses and risk of contamination by edge-of-field runoff. Producers and land managers should be aware of inadequacies of manure nutrient application practices currently in use in conservation row crop production. The variability in the ratio of phosphorus forms persisted over the years and the phenomenon distorts the picture of phosphorus availability in the field, and the formulation of phosphorus recommendations for future growing seasons should an average value of field phosphorus status be used. 02 Opportunities to manage residual nitrate after drought are increasing. Residual nitrate following corn can readily be transported into water resources during the fall-spring water-recharge season in the Humid East. Residual nitrate is highly variable from site-to-site and year-to- year, which prompted a series of studies to evaluate crop monitoring techniques for forecasting sites likely to have high residual nitrate. Results showed that drought was a major factor linked to high residual nitrate. Measures of late-season crop water stress, such as canopy reflectance of visible and near infrared light that can be measured remotely, can provide early identification of drought sites. This early identification of high residual nitrate sites can provide opportunities for targeting cover crops to these sites, which can reduce nitrate losses to water resources during the subsequent water-recharge season in humid regions. 03 A new analytical method for ammonia can monitor ammonia emissions in real time. The development of a new method to measure ammonia losses can improve nitrogen recovery in agriculture and reduce nitrogen losses to the environment. The new ammonia method is based on monitoring the pH changes of an acid trapping solution. The method is accurate and precise, and can rapidly and non-destructively monitor ammonia accumulations in the trapping solution. The new method�s ability to continuously monitor ammonia emissions can provide insights for further developing management practices to reduce ammonia emissions from agriculture.

Impacts
(N/A)

Publications

Hafner, S.D., Meisinger, J.J., Mulbry III, W.W., Ingram, S.K. 2012. A pH- based method for measuring gaseous ammonia. Nutrient Cycling in Agroecosystems. 92(2):195-205.
Forrestal, P.J., Kratochvil, R.J., Meisinger, J.J. 2011. Late-season corn measurements to assess soil residual nitrate and nitrogen management. Agronomy Journal. 104:148-157.
Dao, T.H., Schwartz, R.C. 2010. Mineralizable phosphorus, nitrogen, and carbon relationships in dairy manure at various carbon-to-phosphorus ratios. Bioresource Technology. 101(10):3567-3574.
Kong, X., Dao, T.H., Qin, J., Qin, H. 2009. Effects of soil texture and land use interactions on organic carbon in soils in North China cities' urban fringe. Geoderma. 154(1-2):86-92.
Pavinato, P.S., Dao, T.H., Rosolem, C.A. 2010. Tillage and phosphorus management effects on enzyme-labile bioactive phosphorus availability in brazilian cerrado oxisols and temperature zone typic hapludults. Geoderma. 156(3-4):207-215.
Dao, T.H. 2010. Extracellular enzymes in sensing environmental nutrients and ecosystem changes: Ligand mediation in organic phosphorus cycling. In: Skukla, G.C., Varma, A., editors. Soil Enzymes. Berlin, Germany: Springer. p. 75-102.
Dao, T.H., Schwartz, R.C. 2011. Manure management effects on phosphorus biotransformations and losses during animal production. In: Bunemann, E.K., Oberson, A., Frossard, E., editors. Phosphorus in Action: Biological processes in soil P cycling. Soil Biology. Berlin, Germany: Springer. p. 407-429.
Schwartz, R.C., Dao, T.H., Bell, J.M. 2011. Manure and mineral fertilizer effects on seasonal dynamics of bioactive soil phosphorus fractions. Agronomy Journal. 103(6):1724-1733.

Progress 10/01/11 to 09/30/12

Outputs
Progress Report Objectives (from AD-416): 1. Develop practices to enhance the beneficial use of manure nutrients and reduce offsite losses through management of the environmental fate and transport of organic carbon, nitrogen, and phosphorus derived from poultry, dairy, and beef cattle manures. 2. Develop integrated crop, soil, and dairy/beef/poultry manure management strategies to improve nutrient utilization and minimize leaching and runoff losses. Approach (from AD-416): Real-time tools for rapid C, N, and P detection and multi-element analysis of manures, soils, and crops will be evaluated and adapted to develop precision nutrient management practices under changing soil microenvironment and weather conditions. Process knowledge affecting C, N, and P transformations and detection will be gained to establish databases and develop algorithms to assist in the management of bionutrient mineralization and availability in conservation cropping systems. Progress was made on both project objectives and their subobjectives addressing Problem Statements 1B and C of National Program 214, Component 1 (management, enhancement and utilization of manure nutrients and resources). Long-term soil and nutrient management practices can have lasting effects on the geographic distribution of soil microorganisms, function, and those of non-mobile nutrients such as phosphorus in large fields. The non-random redistribution may influence the rate of turnover of soil nutrients between their inorganic and organic forms and the efficiency at which crops utilize them. The variability observed in the field is also introduced during land applications of animal manure and composts that are themselves variable in nutrient composition. We conducted a field study of land application of dairy manure in a large field planted to corn and determine the distribution of microbial biomass and those of selected metabolic enzymes present in the soil, based on a grid of precisely known geographic coordinates. A high variability existed, and high microbial mass and enzymatic activities in specific locations reflected a localized high rate of nutrient turnover. They were associated with the differences in the microbial properties involved in the production of organic phosphorus-degrading enzymes. However, conventional soil testing procedures do not adequately measure the accumulation or disappearance of these organic P forms. In addition, the large spatial variability noted above highlights the need to improve current soil testing methods for estimating soil biochemical or microbial properties, and recommendations of crop nutrient requirements that are currently based on measurements of a few representative samples collected from selected locations in the field. Surface applied poultry litter can lose 25-50% of its ammonia nitrogen through volatilization. Analysis of wind tunnel ammonia-trap samples was completed from field studies that compared poultry litter application techniques for conserving ammonia. These data are being statistically summarized and interpreted in preparation for publication in refereed journals. Cover crops have an important role in conserving residual nitrogen. Isotope labeled fertilizer was used to directly compare the ability of rye, wheat, and native weeds to recover residual N applied to a preceding corn-silage crop. Soil and crop samples were collected in the early winter, early spring, and late spring and are being analyzed for labeled N to follow changes in soil nitrate and the uptake of labeled N by the winter crops. This study will quantify the effectiveness of cover crop management strategies for capturing residual nitrate, thus reducing nitrate loss to ground water and the Chesapeake Bay. Significant Activities that Support Special Target Populations: In support of special target populations, ARS scientists made a key presentation on x-ray spectroscopic analysis of P in soil and recommendations for managing field spatial variability of soil extractable phosphorus using enzymatic sensing and x-ray fluorescence spectroscopy to a multi-national audience at the International Conference on Enzymes in the Environment held in Bad Nauheim, Germany. The workshop was attended by over 500 scientists and specialists in nutrient research and environmental management. ARS scientist mentored two minority high school interns and developed students� independent science projects on soil enzyme activities and microbial biomass in relation to organic P storage. Helped the interns acquire basic practical research skills to partially fulfill their community service and graduation requirements of the 2011-12 school year. An ARS scientist contributed to the Chesapeake Bay Goal line 2025 Workshop by making two panel keynote presentations on �Nitrogen Management Tools for Reducing Nitrogen losses in the Chesapeake Bay Watershed� and �Ammonia Emissions from Agriculture in the Mid-Atlantic�. These presentations reviewed principles and evaluated best management practices for reducing N losses to the Bay that occur through water and atmospheric pathways. The workshop objective was to equip the local Watershed Implementation Planners with useful tools for writing their individual watershed implementation plans as required for the upcoming Chesapeake Bay nutrient loading limits. The workshop was attended by about 300 people consisting of members of local planning teams, farmers, river keepers, nutrient management consultants, fertilizer and implement dealers, dairy and poultry industries, state environmental agency staffers, state department of agriculture staffers, Natural Resource Conservation Service agents, and Extension Service personnel. An ARS scientist is a federal representative on the Chesapeake Bay Science and Technical Advisory Committee that is composed of 30 members representing marine scientists, hydrologists, soil scientists, agronomists, modelers, economists, waste treatment plant operators, atmospheric scientists, and social scientists from Land Grant Colleges, State, and private organizations. The committee meets quarterly to provide technical reviews and advice on a variety of issues. For example: technical evaluations of strategies to restore the Bay (e.g. use of cover crops, methods to track improvements in the Bay, etc.); identification of future important issues facing the Bay (e.g. global climate change, impact of mining by hydraulic fracturing, etc.); and enhancing program delivery (e.g. develop a Bay Modeling Lab., promulgation of publications). Accomplishments 01 Large within-season fluctuations in soil phosphorus availability. Season and year-to-year changes in available soil phosphorus have frequently be observed and are a source of uncertainty in making fertilizer recommendations in crop production. This is particularly true when soil phosphorus levels are elevated following repeated applications of animal manure to supply nitrogen to crops. Thus, phosphorus applications are an important factor causing these fluctuations, along with unpredictable weather conditions during the pre-season and the entire growing season. ARS scientists at Beltsville and Bushland found levels of soluble phosphorus, such as forms soluble in rainwater, fluctuated significantly in fertilizer-amended plots during two growing seasons of grain sorghum. Manure amended plots also showed large seasonal variations in soil extractable phosphorus, but there was a delayed release of extractable phosphorus that extended well into the growing season. In contrast, the fluctuations in extractable soil phosphorus in control plots that receiv no additional phosphorus were not significant except for organic phosphorus forms. A significant dependence of soluble phosphorus on soil acidity and calcium levels suggested that precipitation and dissolution processes contributed to the observed seasonal phosphorus fluctuations. Fluctuations in both inorganic and organic phosphorus forms were two to four times greater than those observed in the crops. These findings highlight the importance of the contributions of the latter organic phosphorus forms in accounting for seasonal soluble phosphorus changes a the offsite discharge risks they present to readjust current mitigation strategies and practices to reduce the loss of phosphorus from agricultural fields. 02 Adapting X-ray fluorescence spectroscopy for managing soil nutrients. Managing declining nutrient use efficiency in crop production has been a global priority to maintain high agricultural productivity with non- renewable nutrient resources such as phosphorus. Rapid testing methods can increase the number of repeated measurements of soil nutrients and improve the accuracy of estimating the rate of phosphorus needed for optimal crop growth and yield. ARS scientists and China Agricultural University researchers observed that soil phosphorus was highly variable along the length of the fields and across the entire area of all seven adjacent fields after a decade of continuous cultivation. A relationship between phosphorus measured by a rapid x-ray fluorescence technique and plant-available phosphorus forms allowed a description of their geograph distribution based on the x-ray fluorescence technique. Distinct management zones were identified for more precise placement of additiona phosphorus needed for optimal crop growth. The findings documented the direct element-specific analysis by x-ray fluorescence and its high samp throughput make the technology an important component of a new nutrient sensing approach. The adoption of the technology will allow farmers to sustainably manage phosphorus, and other crop nutrients such as potassiu calcium, or chloride in production fields, based on their location- specific variations in the soil. The precision management approach will reduce adverse effects of unequal nutrient distribution on plant productivity or potential loss of nutrient excesses from a field. 03 Injecting liquid manures reduces ammonia losses, but increases other gaseous N losses. Incorporation of liquid manure is often recommended to reduce ammonia losses, to reduce odor, and to reduce nutrient losses in runoff water. However, incorporation with tillage is not compatible with high-residue conservation practices, such as notill production, and is n possible with pasture or perennial forages. Manure injection technologie allow incorporation with limited disruption of the soil surface or plant residue cover. This critical review and analysis found many publications which show that injection of liquid manures can reduce ammonia N emissio by 40-90%, compared to surface application. However, injection can creat anaerobic soil conditions that favor denitrification leading to other gaseous N losses. Research measuring denitrification N losses showed tha up to half of the N that is conserved by reducing ammonia emissions can later be lost as N2 gas (a benign gas) or as nitrous oxide (a greenhouse gas). Improved crop utilization of the N conserved by reducing ammonia emissions is the most common observation following injection, but this benefit can be minimal, which is consistent with greater denitrification losses. We conclude that further research is needed to better understand the N dynamics of injected manures. Accruing a better understanding of these N dynamics will provide scientists, nutrient managers, and policy makers with improved estimates of the effects of manure injection on the fate and transport of manure N. 04 Near- and mid-infrared analysis of biochars and biofuel feedstocks. Ther is increased interest in biochars made from agricultural by-products to store carbon in soil and improve its quality. Near-infrared spectroscop used to determine the composition of numerous agricultural products is a potential method for determining biochars' composition. However, a high degree of baseline curvature and background noises existed upon detailed examination of biochars made from wheat straw. ARS results obtained with scanning monochromator were far superior as it collects more spectral da at a lower resolution to improve their interpretation. Mid-infrared spectroscopy has also been used to rapidly determine fiber components an protein in forages and grains at reduced cost and increased speed. The same components are of interest for biofuel production. Practical and technical differences exist between the two sectors� needs that will dictate how near-infrared and mid-infrared technologies are developed fo the biofuel sector. Direct analysis of fiber components and possibly new spectroscopic methods will be needed. These issues will become increasingly important when feedstocks shift away from starch for producing ethanol or plant oil for producing biodiesel to cellulosics.

Impacts
(N/A)

Publications

White, K.E., Reeves, J.B., Coale, F.J. 2011. Mid-infrared diffuse reflectance spectroscopy for the rapid analysis of plant root composition. Geoderma. 167:197-203.
Dao, T.H., Miao, Y., Zhang, F.S. 2011. X-ray fluorescence spectrometry- based approach to precision management of soil phosphorus and other mineral macronutrients. Agricultural Journal. 103:1724-1733.
Dao, T.H., Cao, Q., Khosla, R., Cui, Z., Chen, X., Miao, Y. 2012. Quantifying spatial variability of indigenous nitrogen supply for precision nitrogen management in small scale intensive farming. Precision Agriculture. 13(1):45-61.
Reeves III, J.B., McCarty, G.W., Calderon, F., Hively, W.D. 2012. Advances in spectroscopic methods for quantifying soil carbon. In: Liebig, MA, Franzluebbers, A.J., and Follett, R. editors. Managing Agricultural Greenhouse Gases. Amsterdam, The Netherlands: Elsevier. 20:345-366.
Dell, C.J., Meisinger, J.J., Beegle, D.B. 2010. Subsurface application of manure slurries for conservation tillage and pasture soils and their impact on the nitrogen balance. Journal of Environmental Quality. 40(2) :352-361.
Pote, D.H., Way, T.R., Kleinman, P.J., Moore Jr, P.A., Meisinger, J.J., Sistani, K.R., Saporito, L.S., Allen, A.L., Feyereisen, G.W. 2011. Subsurface application of poultry litter in pasture and no-till soils. Journal of Environmental Quality. 40:402-411.
Spargo, J.T., Cavigelli, M.A., Mirsky, S.B., Maul, J.E., Meisinger, J.J. 2011. Mineralizable soil nitrogen and labile soil organic matter in diverse long-term cropping systems. Nutrient Cycling in Agroecosystems. 90:253-266.

Progress 10/01/10 to 09/30/11

Outputs
Progress Report Objectives (from AD-416) 1. Develop practices to enhance the beneficial use of manure nutrients and reduce offsite losses through management of the environmental fate and transport of organic carbon, nitrogen, and phosphorus derived from poultry, dairy, and beef cattle manures. 2. Develop integrated crop, soil, and dairy/beef/poultry manure management strategies to improve nutrient utilization and minimize leaching and runoff losses. Approach (from AD-416) Real-time tools for rapid C, N, and P detection and multi-element analysis of manures, soils, and crops will be evaluated and adapted to develop precision nutrient management practices under changing soil microenvironment and weather conditions. Process knowledge affecting C, N, and P transformations and detection will be gained to establish databases and develop algorithms to assist in the management of bionutrient mineralization and availability in conservation cropping systems. X-ray fluorescence spectroscopy was evaluated to determine phosphorus (P) and other minerals such as potassium in manure-amended field soils. Large field plots and different rates of manure phosphorus were established. Measurements of soil and plant conditions were made periodically during the early stages of corn growth and determine variability across the field and rate treatments. The study will be repeated to obtain year-to- year variations in crop growth, responses to climatic conditions, and differences in x-ray spectral results. In order to reduce soluble phosphorus present in excess in manure and field soils, water treatment residues from the Rockville Drinking Water Treatment facility were evaluated in switch grass field plots. Samples were collected, and analyzed for phosphorus and metal contents. The water treatment residues will be applied in the fall of 2011 and will be left to react with the soil in the various grass plots for the remainder of Year one. Real-time active sensors were compared with manual static sensors in field plots growing continuous corn treated with a range of fertilizer nitrogen (N) rates, or poultry litter applied on a P-based or an N-based management strategy. The comparisons are done at the early-vegetative through early-reproductive stages of development of corn to document total N uptake and grain yield and compare the effectiveness of the two types of sensors for assessing corn N stress. Cover crops have an important role in sequestering or harvesting residual nitrogen. Fertilizer depleted of the labeled nitrogen-15 is being used to directly compare the ability of rye, wheat and native weeds to recover residual labeled N applied to a preceding corn-silage crop. Soil and crop samples were collected in the early winter, early spring, and late spring and analyzed for labeled N to follow changes in soil nitrate-N and the uptake of labeled N by the winter crops. This study will quantify the effectiveness of these crop management strategies for capturing residual nitrate, thus reducing nitrate loss to ground water and the Chesapeake Bay. Carbon (C) can accumulate in soils through the carbon contained in roots and their resistance to breakdown. Preliminary results on the composition and degradability of roots showed large variations between plant species. After six weeks, the decomposition varied from 78% for alfalfa roots and 22% for fescue, and 42% for switchgrass. These differences may indicate the importance of plant species on the contribution of roots to carbon sequestration and turnover in soil. Wood and coal-like materials or biochars were also prepared from a large collection of forages and plant by-products using slow heating at 400, 500 and 600 C. Near- and mid- infrared spectral results and yield data are being compiled and statistically analyzed to prepare manuscripts and non-technical summaries. Significant Activities that Support Special Target Populations In support of special target populations, an ARS scientist made a presentation on x-ray spectroscopic analysis of P in soil to a multi- national audience at the 10th International Conference on Precision Agriculture, in Denver, CO. Interest in spectroscopic methods was high; they can be applied to site-specific management of mineral nutrient inputs and improve crop nutrient use efficiency. The spatial variability of soil nutrients is still seen as a major impediment to nutrient-use efficiency and sustainable agricultural production. The X-ray florescent spectroscopy-based approach to soil testing can yield more soil-specific data of available P rather than on the conventional soil testing approach of deriving an average recommendation of fertilizer needed for a specific field or farm based on a few composites of representative locations on the field. An ARS scientist contributed to the Chesapeake Bay Goal line 2025 Workshop by making two panel keynote presentations on �Nitrogen Management Tools for Reducing Nitrogen losses in the Chesapeake Bay Watershed� and �Ammonia Emissions from Agriculture in the Mid-Atlantic�. These presentations reviewed principles and evaluated best management practices for reducing N losses to the Bay that occur through water and atmospheric pathways. The workshop objective was to equip the local Watershed Implementation Planners with useful tools for writing their individual watershed implementation plans as required for the upcoming Chesapeake Bay nutrient loading limits. The workshop was attended by about 300 people consisting of members of local planning teams, farmers, river keepers, nutrient management consultants, fertilizer and implement dealers, dairy and poultry industries, state environmental agency staffers, state department of agriculture staffers, Natural Resource Conservation Service agents, and Extension Service personnel. An ARS scientist is a federal representative on the Chesapeake Bay Science and Technical Advisory Committee that is composed of 30 members representing marine scientists, hydrologists, soil scientists, agronomists, modelers, economists, waste treatment plant operators, atmospheric scientists, and social scientists from Land Grant Colleges, State, and private organizations. The committee meets quarterly to provide technical reviews and advice on a variety of issues. For example: technical evaluations of strategies to restore the Bay (e.g. use of cover crops, methods to track improvements in the Bay, etc.); identification of future important issues facing the Bay (e.g. global climate change, impact of mining by hydraulic fracturing, etc.); and enhancing program delivery (e.g. develop a Bay Modeling Lab., promulgation of publications). An ARS scientist contributed an invited book chapter on the role of organic ligands on the biological transformations of phosphorus for the Springer-Verlag Soil Biology Series to further the understanding of changes in forms of phosphorus in soil amended with phosphate fertilizers or phosphorus-enriched animal manures. ARS novel soil phosphorus testing and rapid sensing techniques for soluble and insoluble forms were described based on how soil microbes and plant roots detect the presence of P-containing materials and acquire phosphorus in the root zone, to assist in the development of practices and strategies to control their movement in the environment. Accomplishments 01 Managing slurry manure based on its carbon-to-phosphorus composition. Determining the fertilizer value and optimal amount of manure to apply t a crop in phosphorus-based cropping systems requires accurate knowledge manure composition, the phosphate content, and conversion rate of organi phosphorus forms to the soluble phosphate by microbes under the conditio existing at the site of storage before land application. ARS scientists demonstrated the linkage between organic-mineral phosphorus conversion t the manure carbon-to-phosphorus composition. As the ratio widened, the conversion of insoluble organic phosphorus to soluble phosphate increase and phosphate accumulated in the slurry regardless of how much phosphate is already present, with an upper limit not to exceed the solubility of insoluble minerals such as calcium phosphates. On-farm manure handling and storage conditions should be managed to minimize this conversion to soluble forms that are easily carried away in water, by adjusting the carbon content in slurries, that is, manure solids, to reduce the slurry carbon-to-phosphorus ratio and lower risks of high levels of mobile and easily lost phosphate to runoff when these manures are land-applied. 02 Small lysimeters were developed to evaluate nitrogen management practice Lysimeters or columns of minimally disturbed soils extracted from the field are valuable tools for comparing the effects of nitrogen managemen practices on water quality, which is an important issue in the Chesapeak Bay watershed. ARS researchers at Beltsville, Maryland, improved procedures for excavation, encasement, transportation, and field-testing of tension-drained lysimeters that were derived from large undisturbed soil cores. Field evaluation of eight intact-core lysimeters showed tha drainage water commonly moves through soils though rapid-flow channels, such as worm holes of root channels, that by-pass much of the soil pore space. No-tillage lysimeters had higher infiltration rates and hydrauli conductivities than lysimeters receiving annual moldboard-plowing, which was attributed to more inter-connected large pores in no-till. It was concluded that the small intact-core lysimeters can reliably measure movement of soluble nutrients, such as nitrate, out of the crop root zon The lysimeter data can thus provide comparisons of the effect of nitrog management practices, like cover crops or tillage or fertilizer timing, nitrate losses to ground water.

Impacts
(N/A)

Publications

Calderon, F.J., Reeves III, J.B., Collins, H.P., Eldor, P.A. 2011. Chemical differences in soil organic matter fractions determined by diffuse-reflectance mid-infrared spectroscopy. Soil Science Society of America Journal. 75(2)568-579.
Palmer, R.E., Meisinger, J.J., Magette, W.L. 2011. Undisturbed soil columns for lysimetry I. Collection, field testing and construction. Applied Engineering in Agriculture. 27(3):379-389.
Palmer, R.E., Hill, R.L., Meisinger, J.J., Magette, W.L. 2011. Undisturbed soil columns for lysimetry II. Miscible displacement and field evaluation. Applied Engineering in Agriculture. 27(3):391-400.
Igne, B., Reeves, J.B., McCarty, G.W., Hively, W.D., Lund, E., Hurburgh, C. R. 2010. Evaluation of PLS, LS-SVM, and LWR for quantitative spectroscopic analysis of soils. Geoderma. 18(3):167-176.