Phosphorus in Runoff from Two Highly Weathered Soils of the Tropics

Ramirez-Avila, J. J., Sotomayor-Ramirez, D. R., Martinez-Rodriguez, G. A., & Perez-Alegria, L. R. (2011). Phosphorus in Runoff from Two Highly Weathered Soils of the Tropics. Canadian Journal of Soil Science. 91(2), 267-277.

Agricultural fields with high soil phosphorus (P) content are important contributors to surface water degradation. Two consecutive simulated rainfall events were conducted on two Ultisols previously amended with inorganic P fertilizer or broiler litter. Soil test P (Bray 1 and Olsen) levels evaluated ranged from 1 to 350 mg kg−1. Surface runoff concentrations of total P (TP) and dissolved P (DP) generated by a 30-min runoff event were quantified. Runoff DP concentrations ranged from 0.08 to 3.98 mg L−1 in fertilizer P-amended soils and from 0.08 to 4.93 mg L−1 in broiler litter-amended soils. A single exponential model adequately described the relationships between soil test P and DP concentrations in runoff. For each soil, the soil test P-DP concentration relationships were positively influenced by soil organic matter and negatively influenced by antecedent soil moisture (P