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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #189888
Title: THE INFLUENCE OF MANURE PHYTIC ACID ON PHOSPHORUS SOLUBILITY IN CALCAREOUS SOILS

Author
item Leytem, April
item Smith, Douglas
item APPLEGATE, T - PURDUE UNIVERSITY
item THACKER, P - UNIV. OF SASKATCHEWAN

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2006
Publication Date: 9/1/2006
Citation: Leytem, A.B., Smith, D.R., Applegate, T.J., Thacker, P.A. 2006. The influence of manure phytic acid on phosphorus solubility in calcareous soils. Soil Science Society of America Journal. 70(5):1629-1638.

Interpretive Summary: Land application of manure can increase phosphorus (P) transfer in runoff, although the risk depends in part on the characteristics of the manure. We assessed this for calcareous soils using manures from poultry (layers or broilers) fed a variety of grain based diets with a range of total P, water extractable P, phytic acid P, total N:P ratios, and total C:P ratios. In addition, two other treatments, mono-ammonium phosphate fertilizer and reagent grade inositol hexa-phosphate (phytic acid), were included, as well as a control treatment with no P additions. Treatments were incorporated into two soils at three rates and incubated for a total of 18 wks with sub-samples taken at 2, 5, 9 and 18 wks. Soil samples were analyzed for inorganic and organic Olsen (bicarbonate) extractable P and select soils were analyzed at 0 and 12 wks by Phosphorus Nuclear Magnetic Resonance Spectroscopy for soil P characterization. The water extractable P concentration of the manures was linearly related to the phytic acid concentration in the manures. Changes in Olsen P over time were related to the percentage of mono-ester P in the treatments, with the treatments having the greatest concentration of mono-ester P having the greatest increases in Olsen P over time. The rate of increases in Olsen P with increasing application rate was greatest for those treatments having the lowest phytic acid contents. Over the incubation period, the influence of phytic acid became less apparent and Olsen P became increasingly related to the amount of carbon or nitrogen that was added with the treatments on the two soils. Changes in phytic acid content of manures due to dietary modification may influence P sorption on calcareous soils in the short-term while other characteristics such as C:P ratio may exert a stronger influence over changes in soil test P over longer time periods.

Technical Abstract: Land application of manure can increase phosphorus (P) transfer in runoff, although the risk depends in part on the characteristics of the manure. We assessed this for calcareous soils using manures from poultry (layers or broilers) fed a variety of grain based diets with a range of total P, water extractable P, phytic acid P, total N:P ratios, and total C:P ratios. In addition, two other treatments, mono-ammonium phosphate fertilizer and reagent grade inositol hexa-phosphate (phytic acid), were included, as well as a control treatment with no P additions. Treatments were incorporated into two soils at three rates and incubated for a total of 18 wks with sub-samples taken at 2, 5, 9 and 18 wks. Soil samples were analyzed for inorganic and organic Olsen (bicarbonate) extractable P and select soils were analyzed at 0 and 12 wks by Phosphorus Nuclear Magnetic Resonance Spectroscopy for soil P characterization. The water extractable P concentration of the manures was linearly related to the phytic acid concentration in the manures. Changes in Olsen P over time were related to the percentage of mono-ester P in the treatments, with the treatments having the greatest concentration of mono-ester P having the greatest increases in Olsen P over time. The rate of increases in Olsen P with increasing application rate was greatest for those treatments having the lowest phytic acid contents. Over the incubation period, the influence of phytic acid became less apparent and Olsen P became increasingly related to the amount of carbon or nitrogen that was added with the treatments on the two soils. Changes in phytic acid content of manures due to dietary modification may influence P sorption on calcareous soils in the short-term while other characteristics such as C:P ratio may exert a stronger influence over changes in soil test P over longer time periods.