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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #396043

Research Project: Sustainable Intensification in Agricultural Watersheds through Optimized Management and Technology

Location: Agroecosystems Management Research

Title: Long-term conservation management practices improve water quality and maintain crop yields in the Upper Midwest

item Rogovska, Natalia
item O'Brien, Peter
item Malone, Robert - Rob
item Emmett, Bryan
item JAYNES, DAN - Retired ARS Employee
item MOORMAN, THOMAS - Retired ARS Employee
item KASPAR, THOMAS - Retired ARS Employee
item PARKIN, TIM - Retired ARS Employee

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2022
Publication Date: 10/15/2022
Citation: Rogovska, N.P., O'Brien, P.L., Malone, R.W., Emmett, B.D., Jaynes, D., Moorman, T.B., Kaspar, T., Parkin, T. 2022. Long-term conservation management practices improve water quality and maintain crop yields in the Upper Midwest. [abstract]. ASA-CSSA-SSSA Annual Meeting.

Interpretive Summary:

Technical Abstract: Nitrate losses from artificial subsurface drainage underlying agricultural fields lead to acceleration of eutrophication and hypoxia in aquatic ecosystems. Adoption of conservation practices, such as cover crops, no-till management, and installation of woodchip bioreactors were shown to significantly reduce nitrate loads in farm field drainage and improve water quality. A small-plot experiment was initiated in 2000 to quantify the long-term effectiveness of such conservation practices on nitrate-N removal rates from subsurface tile drain. Corn and soybeans were grown under no-till with three different treatments: 1) Control, 2) Rye Cover (RC) crop, and 3) in-situ woodchips denitrification wall/ bioreactor (DW) where trenches were excavated parallel to the tile and filled with woodchips serve as additional carbon sources to increase denitrification. Over a period of 12 years (2009-2020), all three treatments received the same annual N fertilization rates ranging from 197 to 240 kg N/ha, depending on the production year. With exception of two years, no significant yield differences were observed between the treatments with exception of two years. Averaged across the 12 years, the RC and DW treatments resulted in consistently lower NO3- loads in drainage compared to Control; 66% and 58% reduction, respectively. Depending on the treatment, May-June rainfall explained 40% to 86% variability in annual NO3--N loss in corn years, but May-June rainfall did not have a clear effect on N loss in soybean years. Results highlight the effectiveness of in-situ bioreactors in nitrate removal from field drainage over period of at least 20 years with nitrate removal rates similar to the rye cover crop treatment.