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United States Department of Agriculture

Agricultural Research Service

Title: Plant Availability of Phosphorus in Swine Slurry and Cattle Feedlot Manure

Authors
item Eghball, Bahman
item Wienhold, Brian
item Woodbury, Bryan
item Eigenberg, Roger

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 1, 2003
Publication Date: March 3, 2004
Citation: Eghball, B., Wienhold, B.J., Woodbury, B.L., Eigenberg, R.A. 2004. Plant availability of phosphorus in swine slurry and cattle feedlot manure. p. 28-35. In A. J. Schlegel (ed.) Proceedings of the Great Plains Soil Fertility Conference, 2-3 March 2004, Denver, CO. Potash and Phosphate Institute, Brookings, SD.

Interpretive Summary: To utilize manure phosphorus (P) for crop production, the amount of P that becomes plant available needs to be quantified. A laboratory incubation study was conducted to determine P mineralization and availability from applied swine and cattle feedlot manure in three soils. Treatments included incubation temperature (52, 64, 77, and 90 oF), P source (swine manure slurry, beef cattle feedlot manure, synthetic fertilizer, and no manure or fertilizer), water regime [constant 60% water filled pore space, (WFPS), and variable water content which included four dry down cycles of 60% to 30% WFPS], time of incubation, and soils (Catlin silt loam, Sharpsburg silty clay loam, and Valentine fine sand). Constant water regime resulted in more P availability from cattle feedlot manure than variable soil water content indicating that P availability under field condition would be less under field condition than laboratory incubation. No significant effect of water regime was observed for the swine slurry. Water-soluble P followed a similar trend as soil test P during incubation. At the low synthetic P fertilizer application rate of about 11 lb P per acre, none of the applied P remained available in the Catlin soil while about 1/3 remained plant available in the Sharpsburg soil and 2/3 in the Valentine soil. Phosphorus availability was 81 to 100 % of applied cattle manure P (85% in field observation) and 62 to 100% of swine slurry P in the three soils. Phosphorus availability in the Sharpsburg soil was 100% of P in both manure types. Phosphorus availability from manure is high and manure can be used similar to inorganic P fertilizer (100% available) in soils with adequate P or in areas susceptible to P loss in runoff. In P deficient soils, a P availability of 70% should be used.

Technical Abstract: To utilize manure phosphorus (P) for crop production, the amount of P that is mineralized and subsequently becomes plant available needs to be determined. A laboratory incubation study was conducted to determine P release and availability from applied swine and cattle feedlot manure in three soils. Treatments included incubation temperature (11, 18, 25, and 32 oC), P source (swine and beef cattle feedlot manure, synthetic fertilizer, and no manure or fertilizer), water regime [constant 60% water filled pore space, (WFPS), and variable water content which included four dry down cycles of 60% to 30% WFPS], time of incubation, and soils (Catlin silt loam, Sharpsburg silty clay loam, and Valentine fine sand). Incubation temperature was not a significant factor in manure P release in this study. Constant water regime resulted in more P mineralization from cattle feedlot manure than variable soil water content (P = 0.06). No significant effect of water regime was observed for the swine slurry. At the low synthetic P fertilizer application rate of 6 ug g-1, about 12 kg P ha-1, none of the applied P remained available in the Catlin soil while about 1/3 remained plant available in the Sharpsburg soil and 2/3 in the Valentine soil. Phosphorus availability was 81 to 100 % of applied cattle manure P (85% in field observation) and 62 to 100% of swine slurry P in the three soils. Phosphorus availability in the Sharpsburg soil was 100% of P in both manure types. Phosphorus availability from manure is high and manure can be used similar to inorganic P fertilizer (100% available) in soils with adequate P or in areas susceptible to P loss in runoff. In P deficient soils, a P availability of 70% should be used.

Last Modified: 4/20/2014
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