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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Source and Amount of Phosphorus on Sorption Kinetics in the Topsoil of a Highly Weathered Soil

Authors
item Brauer, David
item Turner, Kenneth
item Belesky, David

Submitted to: European Journal of Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 16, 2006
Publication Date: February 10, 2007
Citation: Brauer, D.K., Turner, K.E., Belesky, D.P. 2007. Effects of source and amount of phosphorus on sorption kinetics in the topsoil of a highly weathered soil. European Journal of Soil Science. 38:885-893.

Interpretive Summary: Abstract If P from manures or fertilizer is deposited in streams or lakes adjoining agricultural lands, water quality usually becomes degraded. Soil chemical and physical reactions involving the P must be understood thoroughly to predict the risk of surface water transporting P from agricultural land to streams and lakes. In this study, the binding of P to topsoil was studied to compare the effects of adding P from fertilizers or turkey litter in both laboratory incubation and field experiments. Soil’s binding capacity for P decreased to a greater extent when P was added as fertilizer compared to turkey litter. These results are of interest to farmers, soil scientists and watershed managers because they demonstrate by direct comparison that source of P affects the soil’s ability to hold this plant nutrient.

Technical Abstract: Soil chemical and physical reactions involving the phosphorus (P) must be understood thoroughly to predict the risk of surface water transporting P from agricultural land to streams and lakes. Addition of P to soils tends to decrease soil’s capacity to bind P, but the addition of organic constituents can increase or decrease binding capacity. In this study, the kinetics of P sorption by topsoil of an Ultisols (Gilpin silt loam) rom West Virginia, USA receiving P from fertilizers were compared to soils amended with turkey litter in both laboratory incubation and field experiments. Addition of 6.6 and 13.2 Mg turkey litter ha-1 increased Bray1 P levels to about the same level as addition of 53 and 115 kg P ha-1, respectively. Soil’s binding capacity for P decreased to a greater extent when P was added as fertilizer compared to turkey litter: for example, P binding maximum was 360 mg P kg-1 soil (dry weight) when soil was amended with 6.6 Mg turkey litter ha-1 as compared to 260 mg P kg-1 soil (dry weight) when amended with 53 kg P ha-1. This study demonstrates by direct comparison that the decrease in P binding capacity with increasing soil P is less when P is added as turkey litter compared to P fertilizer.

Last Modified: 7/23/2014
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