Effect of liquid livestock manure storage conditions on total and water-extractable phosphorus

Session: Watershed and Lake Science Informing Management (1)

Mary Wicks, Ohio State University, [email protected]
Harold Keener, Ohio State University, [email protected]
Fuqing Xu, Ohio State University, [email protected]
Leipeng Cao, Ohio State University, [email protected]
Zhe Liu, Ohio State University, [email protected]

Abstract

Land application of livestock manure provides nutrients and improves soil but has contributed to outbreaks of harmful algal blooms in Lake Erie and other Ohio lakes. Total phosphorus (P) is typically used to calculate the manure application rate, while dissolved P has higher runoff potential and contributes directly to harmful algal blooms. Manure is usually stored  for up to one year before land application. During storage, microbial activities and physiochemical processes such as mineralization and precipitation change the chemical and physical properties of manure, which may affect the total and dissolved P content. Studies have evaluated the effects of manure storage conditions on gas emissions, but the effect on dissolved P is not clear. Our research investigated the effect of five manure storage times and five temperatures on changes of TP and water extractable P (WEP, represented soluble P) of liquid swine and dairy manure. Other parameters were determined to estimate gas emissions during storage. To compare the lab with real-world data, our team worked with consultants and labs to collect and analyze manure samples from 30+ farms. TP,  WEP, and other parameters were analyzed. This study could provide information on manure management practices that reduce P runoff risk.