Progress 08/01/03 to 07/31/07
Outputs
The ability of organic soil amendments to increase the bioavailability of soil phosphorus has remained uncertain despite extensive work by soil scientists. To gain better understanding of the effect, our work was conducted at the laboratory-, greenhouse-, and field-scale. We consistently observed that the addition of organic amendments increased the phosphorus availability of soils in both field and greenhouse experiments. Our laboratory studies were designed to obtain insight on the chemical processes leading to this increase in phosphorus availability upon organic amendment. Our findings show that the more humified components of organic matter are involved with the interaction with soils which lead to greater soil phosphorus availability in soils. We conducted studies which investigated how microbial decomposition of organic materials affected its effect on increasing soil phosphorus. The results also show consistently that decomposition of the soil amendment increases its ability to interact with soils leading to higher levels of phosphorus being available for crop uptake. Our results also indicated that cropping systems that include crops with higher amounts of root growth may promote increased soluble soil carbon levels and enhance phosphorus bioavailability. TARGET AUDIENCE: This research serves the need of multiple audiences. The fundamental research conducted on the development of chemoinformatic methods for the characterization of soil organic matter has been of interest to the agronomic and soil science research community. The publications of these results in the literature have led to contacts from other researchers inquiring about how to apply these tools for their research interests. The more applied research which has focused on how organic matter derived from organic soil amendments interact with soil phosphorus has been of interest to other research groups studying organic matter ¿ phosphorus interactions. In addition, extension scientist have also benefited from this research as they communicate to growers on how to manage their farms with the goal of maintaining yield of their crops while reducing both potential adverse impacts to the environment and minimizing purchased inputs. Several organic farmers have also inquired about how this research on making more phosphorus more available could be applied to their farms.
PARTICIPANTS: In addition to the project directors, we two graduate students has obtained M.S. degrees based on the research that was funded by this grant. Through the service on the graduate committees of the graduate students, six departmental faculty members and three USDA-ARS scientists have been involved in the development and interpreting the results of the funded research. Through shared research interests, we have collaborated with researchers from the University of Arizona and the Pacific Northwest National Laboratory, as well as researchers from the University of Copenhagen in Denmark and the National Institute for Agro-Environmental Sciences in Tsukuba, Japan.
Impacts
The research conducted consistently show that the addition of organic materials typically used in sustainable agriculture increase the phosphorus availability of soils. The analytical methods developed to characterize soil organic matter had led to a more detailed understanding of how organic matter reacts with soil surfaces which is responsible for this effect. Our studies have also shown the very important role of decomposition in altering the chemical nature of organic matter which has significant effects on the phosphorus status of soils. Traditionally, soil chemical studies have ignored the role of microbial processes on soil chemical reactions. One of the strong impact of our studies is the demonstration that microbial processes are highly significant in soil processes and needs to be investigated if studies are to help elucidate greater understanding of processes which occur at the field scale. The results obtained provide further support that systems which return crop residues and add organic amendments such as animal manures, composts, and biosolids can increase the availability of soil phosphorus, which should lessen the need to add purchased chemical fertilizer inputs.
Publications
- Ohno, T., A. Amirbahman, and R. Bro. 2007. Parallel factor analysis of excitation-emission matrix fluorescence spectra of water-soluble organic matter as basis for the determination of conditional metal binding parameters. Environ. Sci. Technol. (in press).
- Hunt, J.F., T. Ohno, Z. He, and D.B. Dail. 2007. Inhibition of phosphorus sorption to goethite, gibbsite, and kaolin by fresh and decomposed organic matter. Biol. Fertility Soils (in press).
- Ohno, T., B.R. Hoskins, and M.S. Erich. 2007. Soil organic matter effects on plant available and water soluble phosphorus. Biol. Fertility Soils 43:683-690.
- Ohno, T., I.J. Fernandez, S. Hiradate, and J.F. Sherman. 2007. Effects of soil acidification and forest type on water-soluble soil organic matter properties. Geoderma 140:176-187.
- Hunt, J.F., and T. Ohno. 2007. Characterization of fresh and decomposed dissolved organic matter using excitation-emission matrix fluorescence spectroscopy and multi-way analysis. J. Agric. Food Chem. 55:2121-2128.
- Ohno, T., J. Chorover, A. Omoike, and J. Hunt. 2007. Molecular weight and humification index as predictors of adsorption of plant- and manure-derived dissolved organic matter to goethite. Eur. J. Soil Sci. 58:125-132.
- Hunt, J.F., T. Ohno, Z. He, C.W. Honeycutt, and D.B. Dail. 2007. Influence of decomposition on chemical properties of plant- and manure-derived dissolved organic matter and sorption to goethite. J. Environ. Qual. 36:135-143.
- Ohno, T., Z. Wang, and R. Bro. 2008. PowerSlicing to determine fluorescence lifetimes of water-soluble organic matter derived from soils, plant biomass, and animal manures. Anal. Bioanal. Chem. (in press).
- Ohno, T., A. Amirbahman, and R. Bro. 2008. Parallel factor analysis of excitation-emission matrix fluorescence spectra of water-soluble organic matter as basis for the determination of conditional metal binding parameters. Environ. Sci. Technol. 42:186-192.
- Hunt, J.F., T. Ohno, Z. He, and D.B. Dail. 2007. Inhibition of phosphorus sorption to goethite, gibbsite, and kaolin by fresh and decomposed organic matter. Biol. Fertility Soils 44:277-288.
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Progress 10/01/05 to 09/30/06
Outputs
Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite of fresh and decomposed hydrophilic (HPL) and hydrophobic (HPB) DOM fractions extracted from the shoots and roots of crimson clover residue (Trifolium incarnatum L.), corn residue (Zea mays L.), soybean residue (Glycine max L. Merr.), hairy vetch residue (Vicia villosa L.), and dairy and poultry manures. Sorption was positively related to apparent molecular weight (MWAP), aromaticity as measured by absorptivity at 280 nm and phenolic acid content. A ten-day laboratory decomposition of the source organic matter generally increased the sorption of the extracted DOM onto goethite. The decomposition effect on sorption was greater for the HPL fractions than for the HPB fractions.
There was a decrease in the MWAP values of the DOM samples following sorption to goethite. We conclude that microbially-driven decomposition processes can result in greater sorption of plant and manure-derived DOM to soil solids, thereby leading to increases in the soil organic C pool. The direct effects of dissolved organic matter (DOM) on the sorption of orthophosphate onto gibbsite, goethite, and kaolin were examined using an one-point phosphorus sorption index and the linear Tempkin isotherm model. Changes in the chemical and sorptive characteristics of the DOM in the absence and presence of added orthophosphate (50 mg L-1) were also determined. For residue-derived materials, DOM sorption to all minerals correlated well with % hydrophobicity, apparent molecular weight and phenolic acidity in the absence of added orthophosphate. Sorption of DOM to goethite and gibbsite was significantly decreased in the presence of added P, as were the correlations between the aforementioned
chemical properties and sorption. Thus, addition of P substantially lowered fractionation of DOM following sorption to goethite and gibbsite. In contrast, few significant P sorption induced differences were observed in the kaolin system. Phosphorus sorption to gibbsite was significantly inhibited by 50 mg CTS L-1 derived from decomposed corn residue, fresh dairy manure residue and oxalate solution. At 200 mg CTS L-1, all DOM solutions were found to inhibit P sorption to gibbsite. This study suggests that DOM inhibition of P sorption depends on the chemical properties of both the sorbent and the DOM itself. In general, DOM from decomposed organic materials inhibited P sorption to a greater extent than did DOM derived from fresh materials. This stronger inhibition highlights the importance of microbial processes in the release of soluble soil P, a key determinant of P availability to plants.
Impacts
This research has the goal of better understanding how soil organic matter affects the availability of phosphorus to crops. Better knowledge of the this interaction will allow better crop management systems whcih reduce the quantity of phosphorus fertilizer needed.
Publications
- Hunt, J.F., T. Ohno, Z. He, C.W. Honeycutt, and D.B. Dail. 2006. Influence of Decomposition on Chemical Properties of Plant- and Manure-Derived Dissolved Organic Matter and Sorption to Goethite. J. Environ. Qual. (in press)
- Ohno, T., B.R. Hoskins, and M.S. Erich. 2006. Soil organic matter effects on plant available and water soluble phosphorus. Bio. Fertility Soils (in press)
- Banaitis, M.R., H. Waldrip-Dail, M.S. Diel, B.C. Holmes, J.F. Hunt, R.P. Lynch, and T. Ohno. 2006. Investigating sorption-driven dissolved organic matter fractionation by multi-dimensional fluorescence spectroscopy and PARAFAC. J. Colloid Interface Sci. 304:271-276 .
- Ohno, T, and R. Bro. 2006. Dissolved organic matter characterization using multi-way spectral decompositon of fluorescence landscapes. Soil Sci. Soc. Am. J. 70:2028-2037.
- He, Z., T. Ohno, B.J. Cade-Menun, M.S. Erich, and C.W. Honeycutt. 2006 Spectral and chemical characterization of phosphates associated with humic substances. Soil Sci. Soc. Am. J. 70:1741-1751.
- Ohno, T., J. Chorover, A. Omoike, and J. Hunt. 2006. Molecular weight and humification index as predictors of adsorption of plant- and manure-derived dissolved organic matter to goethite. Eur. J. Soil Sci. (in press)
- Sherman, J., I.J. Fernandez, S.A. Norton, T. Ohno, and L.E. Rustad. 2006. Soil aluminum, iron, and phosphorus dynamics in response to long-term experimental nitrogen and sulfur additions at the Bear Brook Watershed in Maine, USA. Environ. Monitoring Assesment 121:419-427.
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Progress 08/01/03 to 07/31/06
Outputs
Activities included utilizing of the multi-way PowerSlicing chemoinformatic method to fit time-resolved fluorescence decay profiles to chemically meaningful components. These methods were discussed at the 2007 American Chemical Society Meeting.
Impacts
The non-iterative PowerSlicing method was shown to simultaneously fit multi-wavelength flourescence decay profiles which provides a better coverage of the fluorescence landscape than the traditional single wavelength decay profile used.
Publications
- Ohno, T., A. Amirbahman, and R. Bro. 2007. Parallel factor analysis of excitation-emission matrix fluorescence spectra of water-soluble organic matter as basis for the determination of conditional metal binding parameters. Environ. Sci. Technol. (in press).
- Hunt, J.F., T. Ohno, Z. He, C.W. Honeycutt, and D.B. Dail. 2007. Influence of decomposition on chemical properties of plant- and manure-derived dissolved organic matter and sorption to goethite. J. Environ. Qual. 36:135-143.
- Hunt, J.F., T. Ohno, Z. He, and D.B. Dail. 2007. Inhibition of phosphorus sorption to goethite, gibbsite, and kaolin by fresh and decomposed organic matter. Biol. Fertility Soils (in press).
- Ohno, T., B.R. Hoskins, and M.S. Erich. 2007. Soil organic matter effects on plant available and water soluble phosphorus. Biol. Fertility Soils 43:683-690.
- Ohno, T., I.J. Fernandez, S. Hiradate, and J.F. Sherman. 2007. Effects of soil acidification and forest type on water-soluble soil organic matter properties. Geoderma 140:176-187.
- Hunt, J.F., and T. Ohno. 2007. Characterization of fresh and decomposed dissolved organic matter using excitation-emission matrix fluorescence spectroscopy and multi-way analysis. J. Agric. Food Chem. 55:2121-2128.
- Ohno, T., J. Chorover, A. Omoike, and J. Hunt. 2007. Molecular weight and humification index as predictors of adsorption of plant- and manure-derived dissolved organic matter to goethite. Eur. J. Soil Sci. 58:125-132.
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Progress 10/01/04 to 09/30/05
Outputs
Sorptive retention of organic matter is important to maintaining the fertility and quality of soils in agricultural ecosystems. However, few sorption studies have been conducted using dissolved organic matter (DOM) characteristic of agricultural amendments. We investigated the sorption to goethite of DOM extracted from: above-ground biomass of wheat straw (Triticum aestivum L.), corn residue (Zea mays L.), soybean residue (Glycine max (L.) Merr.), and hairy vetch residue (Vivia billosa L.); below-ground biomass from corn, soybean, canola (Brassica napus L.), and green bean (Phaseolus vulgaris L.); and beef, dairy, poultry, and swine animal manures. The apparent molecular weight (MWAP) of the DOM was measured by high performance-size exclusion chromatography and ranged from 312 to 1074 g mol-1. The carboxyl-group content of the DOM measured by potentiometric titration ranged from 4.84 to 21.38 mmol(-) g -1 carbon. The humification index (HIX) determined by fluorescence
spectrometry varied from 1.15 to 4.33. Sorption was directly related to both MWAP and HIX values of the DOM ligands. Molecular weight analysis of the solution prior to and after sorption indicated that the DOM molecules >1800 g mol-1 were preferentially sorbed resulting in fractionation of the DOM upon reaction with goethite. The multiple regression equation, based only on MWAP and HIX parameters, explained 76% of the variance. The results indicate that MW and HIX are important factors in controlling the sorption of DOM to mineral surfaces. PARAFAC analysis of the DOM fluorescence spectra revealed four components (fluorophores). Comparison of the fluorophore concentrations before and after sorption indicated that only fluorophore #2 with an EX maximum at 320 nm and EM maximum at 450 nm was sorbed. This fluorophore has been characterized as fulvic-like by other researchers. The multiple regression equation obtained for goethite was Sorption = 11.38 + 46.9(fluorophore #2) +0.021(MW), r2
= 0.72. This result indicate that MW and concentration of the fulvic-like fluorophore are important factors in controlling the sorption of DOM to the goethite surface.
Impacts
The results from this years work shows that crop species play an important role in determing the levels of dissolved organic matter in soil solution. There is a clear relationship between the level of soil phosphorus in solution and the amount of dissolved organic matter. Thus, choices made in crop selection can impact the amount of phosphorus available to plants.
Publications
- Montgomery, M., T. Ohno, T.S. Griffin, C.W. Honeycutt and I.J. Fernandez. 2005. Phosphorus mineralization and bioavailability in soils amended with biosolids and manures. Bio. Agric. Hort. 22:321-334.
- Ohno, T., T.S. Griffin, M. Liebman, and G.A. Porter. 2005. Green- and animal-manure based cropping systems effects on soil phosphorus and organic matter. Agric. Ecosystem Environ. 105:625-634.
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Progress 10/01/03 to 09/30/04
Outputs
Progress was focused on two aspects in this reporting period. A field study involving how root biomass impacts the level of dissolved organic carbon was carried out and accomplished. Rooting density was significantly different among different crop treatments and also related to the concentration of dissolved organic carbon in the soil solution. Furthermore, dissolved organic carbon levels and soluble phosphorus levels were directly related indicating the importance of dissolved organic matter in determining the solubility of soil phosphorus. Laboratory studies focussed on setting up the HPLC based size exclusion chromatography system for determination of molecular weight for dissolved organic matter extracted from soils, plant biomass and manures. A study was conducted to determine the sorption of dissolved organic matter isolated from plant materials and animal manures on both goethite and kaolin minerals. Sorption was greater for goethite and molecular weight
analysis indicated that fractionation of the organic matter occured due to preferential sorption of the higher molecular weight fraction.
Impacts
The results from this years work shows that crop species play an important role in determing the levels of dissolved organic matter in soil solution. There is a clear relationship between the level of soil phosphorus in solution and the amount of dissolved organic matter. Thus, choices made in crop selection can impact the amount of phosphorus available to plants.
Publications
- No publications reported this period
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