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

Abstract

Soil chemical and physical reactions involving phosphorus (P) must be understood to predict the risk of P being transported from agricultural land to streams and lakes. The kinetics of P sorption by an Ultisols from West Virginia, USA, receiving P from fertilizers were compared to soils amended with turkey litter. Addition of 6.6 and 13.2 Mg turkey litter ha⁻¹ increased Bray 1P levels to about the same level as adding 53 and 115 kg P ha⁻¹, respectively. Phosphorus binding capacity decreased to a greater extent when P was added as fertilizer as compared to turkey litter. For example, P binding maximum was 360 mg P kg⁻¹ dry soil when soil was amended with 6.6 Mg turkey litter ha⁻¹ as compared to 260 mg P kg⁻¹ dry soil when amended with 53 kg P ha⁻¹. This study demonstrates that the decrease in P‐binding capacity with increasing soil P is less when P is added as turkey litter.

Keywords:

• Binding capacity
• binding constant
• fertilizer
• mineralization
• phosphorus
• sorption
• turkey litter