QUANTIFICATION OF WATER EXTRACTABLE PHOSPHORUS POOLS IN SOILS AND MANURES TO PREDICT PHOSPHORUS LOSS

Abstract

Phosphorus (P) is an essential nutrient for sustaining plant, animal, and human health, but can be a pollutant in water bodies. In intensive animal agriculture regions globally, long-term manure application has led to an abundance of P in soils. Exploitation of finite reserves of P is concerning for the future of agriculture and water quality. This research investigates how better understanding the most labile pool of P in soils and manures, i.e., water-extractable P (WEP), can lead to better quantification and risk-assessment of P loss. High P soils were extracted using varying methodology to improve long-term P loss risk assessment. Poultry litter and products were added to a soil to understand how WEP-based application (WEP) affects the loss of dissolved P forms in runoff. We conclude that an accurate quantification of WEP in both soils and manures is needed to improve manure management and mitigate P loss to waterways.