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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #347348
Title: Conservation dairy farming impact on water quality in a karst watershed in northeastern US

Author
item AMIN, MOSTOFA - Bangladesh Agricultural University
item KARSTEN, HEATHER - Pennsylvania State University
item Veith, Tameria - Tamie
item BEEGLE, DOUGLAS - Pennsylvania State University
item Kleinman, Peter

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/18/2018
Publication Date: 6/28/2018
Citation: Amin, M.M., Karsten, H.D., Veith, T.L., Beegle, D.B., Kleinman, P.J. 2018. Conservation dairy farming impact on water quality in a karst watershed in northeastern US. Agriculture System. 165:187-196. https://doi.org/10.1016/j.agsy.2018.06.010.
DOI: https://doi.org/10.1016/j.agsy.2018.06.010

Interpretive Summary: Studies have shown that conservation management such as cover cropping, no-till planting, and manure injection can help reduce nutrient loss from a farm without reducing crop yield or costing the farmer too much. However, it is less clear how these practices will affect water quality for a karst watershed when all farms in the watershed use the practices. We modeled a karst, agricultural watershed and represented farm management throughout the watershed in each of four scenarios: 1) no conservation management, 2) some conservation management (typical for the region), 3) cover cropping and no-till planting with broadcast manure, 4) cover cropping and no-till planting with injected manure. We found that crop yield was nearly the same in all 4 scenarios but that scenarios 3 and 4 improved water quality by reducing in-stream nutrients and sediment and improved air quality by reducing greenhouse gas emissions. These findings will help us design conservation management tools that support Chesapeake Bay Program efforts to reduce nutrient and sediment loadings from agricultural lands while also supporting farm productivity and economic viability.

Technical Abstract: One crucial challenge of agriculture is to increase productivity to feed the continuously growing population without deteriorating soil, water, and environmental quality. More emphasis on improved efficiencies, appropriate management of agricultural systems, and improved agronomic and nutrient use practices are needed to address this challenge. A conservation dairy cropping, with no-till, continuous diversified plant cover, and manure injection has recently been developed and tested in Pennsylvania, but the effect of this newly developed cropping system on nonpoint source pollution at the watershed scale is yet to be investigated. Topo-SWAT, a variation of the Soil and Water Assessment Tool (SWAT), was used to simulate nutrient and chemical loading processes of four dairy cropping scenarios that implemented different nutrient input strategies: (i) no-BMP (no best management practice) management; (ii) typical Pennsylvania management, which contains some no-till and cover cropping; (iii) conservation management with broadcast manure; and (iv) conservation management with injected manure. The conservation scenario with injected manure was the most effective for reducing total nutrient (42% N and 51% P) and sediment (41%) load in the watershed. The typical scenario also reduced nutrient and sediment load compared to the no-BMP scenario. Both conservation scenarios significantly reduced the number of in-stream peaks of organic N (84–89%), nitrate (62–64%), organic P (40–49%), and soluble P (68–75%) concentration compared to the no-BMP scenario. Introduction of manure injection hindered runoff-mediated loss of nutrients but not leaching. Both conservation scenarios also decreased nitrous oxide emission by reducing denitrification. Additionally, manure injection retarded 91% of the N volatilization that occurred in manure broadcast scenario. The watershed scale study indicates that implementation of the conservation scenarios in dairy cropping systems can largely contribute to the initiatives of achieving a target total maximum daily load in the Chesapeake Bay and incorporating manure also can aid air quality as well.