Chakraborty, D1; Prasad, R.2
1Research Fellow I, Auburn University, Auburn, AL, 36849
2Extension Specialist and Assistant Professor, Auburn University, Auburn, AL, 36849


Poultry is the second-largest agricultural industry in Alabama with an economic impact of $15.1 billion in revenue. Poultry litter (PL) is bulky which limits their economical long-distance transportation. Repeated land applications of PL result in the buildup of phosphorus (P) in the soil leading to the creation of “P hotspots” near the poultry operations. This accumulated P in soil is susceptible to P loss via runoff and promote eutrophication of surface water. Wedowee watershed in Alabama has witnessed the expansion of poultry operations in the last five years. Lake Wedowee is the major source of water for public drinking supply and P runoff during storm events can increase the P loading rate and potentially deteriorate the water quality of the lake. Tools such as P index or soil test P are used to estimate the risk of P loss; however, there is a growing concern that these tools are not able to correctly identify P hotspots or prioritize implementation of best management practices to reduce P loading during runoff events. The objective of this study was a) to use the concept of Soil P Storage Capacity (SPSC) to identify P hotspots in Lake Wedowee watershed, and b) to predict the potential risk of P loss during runoff events using the approach of SPSC. Soil samples up to 60 cm depth were collected from farms located in Wedowee watershed. These farms had a history of poultry litter application. The soil samples were processed and SPSC was determined according to the procedures of Chakraborty et al, 2012. Results indicate that SPSC can be used as a site assessment tool to predict the nature of P hotspots, i.e. whether a site is acting as a source or sink of P and the amount of P they can potentially discharge during rainfall events. This work will help to prioritize the implementation of best management practices to reduce P loading in the Wedowee watershed.

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