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Differential Availability of Manure and Inorganic Sources of Phosphorus in Soil
Author(s) -
Sharpley Andrew N.,
Sisak Istvan
Publication year - 1997
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1997.03615995006100050030x
Subject(s) - manure , poultry litter , soil water , fertilizer , leachate , phosphorus , sorption , chemistry , agronomy , litter , environmental science , environmental chemistry , nutrient , soil science , biology , adsorption , organic chemistry
As little information is available on whether differences in the availability of manure and fertilizer P in soil exist, manure management recommendations are being based on fertilizer response. Thus, the availability of P (as Fe‐oxide strip P) from poultry litter leachate or KH 2 PO 4 was investigated by incubation for 7 d with 193 soils with a wide range of properties associated with P sorption. Phosphorus availability, calculated as the slope of the linear relationship ( F ) between strip P and P added (0–108 mg inorganic P kg −1 ), was consistently greater for soils treated with KH 2 PO 4 ( F k of 0.50) than litter leachate ( F 1 of 0.29). Although F k and F l were linearly related ( r 2 of 0.92), relative availabilities were inversely related to the ratio of soil clay/organic C content ( r 2 of 0.68), an estimate of the reactive surface area involved in P sorption and availability. The differential availability in soil of the two sources of P is attributed to the complexation of P with Ca and organo‐Ca, Fe, and Al, with the addition of Ca and soluble organic compounds in poultry litter leachate. Thus, manure management recommendations should be based on yield trials for manure and its availability in soil rather than on fertilizer P. Current fertilizer recommendations may be modified by soil CaCO 3 , extractable Fe, and clay/organic C to account for the differential availability of manure and inorganic P sources in soil.