Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #412255
Research Project: Sustainable Intensification in Agricultural Watersheds through Optimized Management and Technology

Location: Agroecosystems Management Research

Title: Impact of conservation practices on nitrogen leaching in artificially drained Midwestern Mollisols

Author
item Rogovska, Natalia
item O'Brien, Peter
item Malone, Robert - Rob
item Emmett, Bryan
item Kovar, John
item JAYNES, DAN - Retired ARS Employee
item KASPAR, THOMAS - Retired ARS Employee
item MOORMAN, THOMAS - Retired ARS Employee
item KYVERYGA, PETER - Iowa State University

Submitted to: Soil and Water Conservation Society International Annual Conference
Publication Type: Abstract Only
Publication Acceptance Date: 2/28/2024
Publication Date: 7/24/2024
Citation: Rogovska, N.P., O'Brien, P.L., Malone, R.W., Emmett, B.D., Kovar, J.L., Jaynes, D., Kaspar, T., Moorman, T.B., Kyveryga, P. 2024. Impact of conservation practices on nitrogen leaching in artificially drained Midwestern Mollisols [abstract]. Soil and Water Conservation Society

Interpretive Summary:

Technical Abstract: Artificial agricultural drainage is an important land management tool widely adopted throughout poorly drained regions like the glaciated Midwest. While beneficial for crop production, tile drainage alters hydrology of the watersheds and promotes nutrient losses, especially nitrate-N, to natural water bodies. A replicated plot experiment was initiated to quantify the effectiveness of conservation practices on reduction of nitrate-N leaching in subsurface tile drains. Maize (Zea mays L.) and soybean (Glycine max L. Merr.) were grown with three different treatments: 1) Control: no-till crop production, 2) RC: no-till with a winter rye (Secale cereale L.) cover crop), and 3) DW: no-till with an in-situ woodchip denitrification wall with trenches excavated parallel to the tile on both sides and filled with woodchips. During a period of 19 years (2002-2020), all three treatments received the same annual N fertilization in maize years, split between planting and side-dress application. Nitrogen rates ranged from 168 to 247 kg N/ha, depending on the Late-Spring Soil Nitrate Test. Averaged across the 19 years, the RC and DW treatments reduced N leaching by 59 and 58%, respectively, compared with the Control farming practice. Both conservation practices were effective for the duration of the study and both practices were affected by annual rainfall. Effectiveness of RC increased in relatively dry years while effectiveness of DW increased in wet years. The effectiveness of the RC treatment was related to biomass growth during the fallow period between the maize and soybean crops. Overall, treatment and annual precipitation had the greatest effects on annual N loss in drainage. This suggests that the unpredictability of rainfall may make it difficult to consistently reduce nitrate losses in drainage, but it does not diminish the effectiveness of conservation practices in curbing nitrate losses.