Location: Soil, Water & Air Resources ResearchTitle: Nitrogen losses in response to conservation practices and sustainable intensification of corn-soybean cropping systems in the Upper Midwest
|Malone, Robert - Rob|
|CAMBARDELLA, CYNTHIA - Retired ARS Employee|
|JAYNES, DANIEL - Retired ARS Employee|
|KASPAR, THOMAS - Retired ARS Employee|
|PARKIN, TIMOTHY - Retired ARS Employee|
Submitted to: Soil and Water Conservation Society Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/26/2021
Publication Date: 7/28/2021
Citation: Emmett, B.D., O'Brien, P.L., Malone, R.W., Kovar, J.L., Cambardella, C.A., Jaynes, D.B., Kaspar, T.C., Kohler, K.A., Moorman, T.B., Parkin, T.B. 2021. Nitrogen losses in response to conservation practices and sustainable intensification of corn-soybean cropping systems in the Upper Midwest [abstract]. Soil and Water Conservation Society Proceedings.
Technical Abstract: Nutrient losses in subsurface drainage water and gaseous losses of nitrous oxide reduce nutrient use efficiency and create unwanted environmental impacts. Management of nutrients and cropping systems offers potential for mitigating these losses. We compared four different cropping systems with respect to N losses at a field site in central Iowa. All cropping systems included corn and soybeans grown in alternate years. N management in corn years (2016 and 2018) consisted of (1) an early spring-applied fixed N rate with spring chisel plow and disking, (2) N applied in late spring according to LSNT with no-tillage; (3) N applied in late spring according to LSNT with no-tillage and rye (Secale cereale) cover crops preceding corn or soybean; (4) N applied in late spring according to LSNT with mixed cover crops preceding corn or winter camelina (Camelina sativa) preceding soybean. No N was applied to soybeans (2017 and 2019), but 67 kg N/ha was applied to camelina. Each treatment was applied to 4 replicated 0.13 ha plots that had individual subsurface tile drains equipped to monitor flow and provide samples for nutrient analysis. N2O was measured in each plot using static chambers sampled weekly from spring thaw to harvest and biweekly until winter freeze. Both rye and camelina reduced nitrate loss in subsurface drainage, but the rye was more effective. Nitrous oxide losses were greater for the camelina relay cropping system and the early spring applied fixed-N rate compared to the other two systems. Results highlight the importance of multiple complementary conservation or best management practices to reduce N losses from corn-soybean cropping systems.