Evaluation of water quality benefits of manureshed based manure management in the Susquehanna River Basin

TitleEvaluation of water quality benefits of manureshed based manure management in the Susquehanna River Basin
Publication TypeConference Proceedings
Year of Publication2022
AuthorsSaha A, Saha G, Cibin R, Spiegal S., Kleinman PJA
Conference NameProceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Date Published7/16/2022
ARIS Log Number387613

The ‘manureshed’ concept is aimed at generating sustainable manure balanced systems by connecting crop areas (nutrient sinks) with livestock agriculture (nutrient sources). This study aims to quantify the potential water quality benefits derived from manureshed based nutrient management through scenario-based analyses in the Susquehanna River Basin (SRB) using Soil and Water Assessment Tool (SWAT). Three manure management scenarios were accessed based on the manureshed concept - (i) Baseline scenario assuming minimal manure transportation, manure generated in a HUC-12 is distributed in the same watershed, (ii) Manure Balanced scenario that considers no excess manure application, excess manure in a HUC-12 watershed is transported to nearest available sink watersheds; (iii) Optimized Priority scenario that assumes manure is fully transportable and manure is not applied in vulnerable areas. The manure application rates were estimated considering both N based and P based crop nutrient demands, totaling six manure application scenarios. The crop N demand-based manure application apply excess P and P based application needed supplemental N inorganic fertilizer application to meet crop nutrient demand. Evaluation of manureshed concept-based manure redistribution scenarios indicated a decrease in nutrient loads at the watershed outlet and an improvement in nutrient uptake by the crops. The N based manure balanced scenario estimated 6% and 26% reductions in organic N and nitrate loss, respectively compared with baseline scenario having the same quantity of total manure applied in the watershed. P based manure balanced scenario simulated 4% reduction in nitrate loss in comparison to the baseline condition. The N and P based optimized scenario simulated 25% and 15% reduction in nitrate loss respectively when compared to baseline scenario. For phosphorous, N and P based manure application in manure balanced scenario indicated a reduction of 9% and 11% sediment P loss, respectively when compared with the baseline. In optimized priority manure application scenario, the model estimates indicate 12% and 19% reduction of sediment P loss from the baseline for both N and P based manure application respectively. The scenario evaluations indicate that the manureshed concept provides an opportunity for sustainable manure management with increased nutrient use efficiency.