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United States Department of Agriculture

Agricultural Research Service

2010 Annual Report

1a.Objectives (from AD-416)
1. Identify the physical and chemical characteristics of manure and soil-manure interactions that influence phosphorus transformations to determine controlling mechanisms of phosphorus mobilization and bioactivity.

2. Develop rapid and accurate on-farm measurement tools to quantify bioactive phosphorus in manure and manure amended soils for managing whole-farm phosphorus balance.

3. Develop zeolitic materials and other by-products and novel methods for phosphorus immobilization, removal, and recovery from manure based on bioactive phosphorus chemistry and mechanisms of phosphorus mobilization.

4. Develop manure and soil parameters and module that links organic phosphorus transformations to the cycling of carbon and nitrogen to refine the Root Zone Water Quality model.

1b.Approach (from AD-416)
An integrated approach involving laboratory and field research and modeling will be used to improve the understanding of phosphorus transformations, mobilization, and fate to control its environmental losses. A comprehensive study of phosphorus mineralization in manure and manure-amended soils will be conducted. Improved quick tests by infrared spectroscopy and biological assays and modeling and decision-support tools, will be developed to evaluate effects of manure management practices on soil active and time-dependent phosphorus pools. Immobilization and recovery of phosphorus by zeolitic materials and evaluations of the potential re-solubilization of phosphorus that was immobilized using soil and manure additives will be made to add to whole-farm management options.

3.Progress Report
In-season variations in phosphorus solubility and availability pointed to the need for real-time detection and precision management of phosphorus and other plant nutrient inputs on the farms. In FY 2010, X-ray fluorescence spectroscopy was applied to determine phosphorus and other minerals such as potassium in animal manure and manure-amended soils. The high throughput and multi-element and elemental specificity of x-ray fluorescence was evaluated as a detection tool for on-farm applications and precision management of nutrient inputs. Phosphorus measurement conditions are being developed to optimize sensitivity and accuracy of the instrument for variable matrix characteristics and derive optimal application rates of animal manure that is highly variable in nutrient content and availability to crop plants.

The results of a study of the effects of ash from the combustion of poultry litter obtained from broiler and layer operations were statistically analyzed and summarized to prepare a peer-reviewed article. Based on these results, further studies are designed to determine the effects of P sources, that is the two ash residues and calcium phosphate on phosphorus and arsenic uptake by corn, wheat and soybean. In addition, the effects of wallboard gypsum and synthetic gypsum on root growth of corn and soybean are being measured.

1. Complementary enzyme activities and biologically-mediated release of manure phophorus. The decomposition of organic forms of manure-borne phosphorus and release of inorganic P is tied to the carbon and nitrogen turnover. While phosphohydrolases were primarily responsible for the dephosphorylation of organic P forms in manures and amended- soils, enzymes responsible for the breakdown of carbohydrates, glucosidases, and cellulases complemented the activity of organic P-degrading enzymes to improve the accessibility of P-containing substrates and enhance the release of inorganic P in dairy manure suspension. Other catabolic enzymes are also released in the soil solution. The solubilization of organic P, a forerunner process of organic P degradation is crucial to the function of extracellular phosphohydrolases in accessing the recalcitrant soil organic P pool. From an environmental standpoint, the contribution of biologically mediated processes to organic P release and movement must be fully understood to develop sustainable nutrient management practices for our cropping systems and mitigate eutrophic responses in environmentally sensitive aquatic ecosystems.

2. Plant-available phosphorus from ash of incinerated poultry litter. ARS scientist conducted greenhouse studies to evaluate the effects of broiler and layer manure ash on the growth and phosphorus and arsenic uptake of corn, wheat and alfalfa. ARS scientist at Beltsville, Maryland, conducted greenhouse studies to evaluate the fertilizer value of broiler litter ash, layer manure ash, compared to inorganic calcium phosphate for corn, wheat, and soybean growth and phosphorus and arsenic uptake. Results demonstrated that only corn exhibited increased dry matter with added calcium phosphate, higher than that shown by the broiler and layer manure ash additions. Phosphorus concentrations in the crops grown in the calcium phosphate treatment were higher or equal to those of the plants grown on the broiler and layer manure ash treatments in the plants grown on the calcium phosphate treatment. Arsenic concentrations were lower in the crops grown on broiler and layer manure ash treatments. These findings showed that the P in the ash was likely less soluble and available to the crop plants, than calcium phosphate, or a purified form of rock phosphate.

5.Significant Activities that Support Special Target Populations
• During FY10, ARS scientist assisted research scientist of the Smithsonian Institute in the assessment of nutrient behavior in Indonesian and Mexican soils under various canopy management and fertilization strategies.

• ARS scientist contributed an invited book chapter on biotransformations of P and losses from animal production systems for the Springer-Verlag Soil Biology Series. Scientist also made a presentation on x-ray spectroscopic analysis of P in soil to an international audience at the third Asian Conference on Precision Agriculture, in Beijing, China. Interest in these spectroscopic approaches was high as they can be applied to improve nutrient use efficiency to reduce potential impairment of the environment by production agriculture.

Review Publications
Cavigelli, M.A., Dao, T.H. 2008. Residual impact of raw and composted poultry litter on soil carbon pools. Electronic Journal of Integrative Biosciences [serial online]. 6:30-40.

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.

Last Modified: 3/31/2015
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