Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 19, 2011
Publication Date: October 19, 2011
Citation: Kaspar, T.C., Jaynes, D.B., Parkin, T.B., Moorman, T.B., Singer, J.W. 2011. Effectiveness of oat and rye cover crops in reducing nitrate losses in drainage water. American Society of Agronomy Annual Meetings [abstracts]. ASA-CSSA-SSSA Annual Meeting. Oct. 16-19, 2011, San Antonio, TX. CD-ROM. Technical Abstract: A significant portion of the NO3 from agricultural fields that contaminates surface waters in the Midwest Corn Belt is transported to streams or rivers by subsurface drainage systems or “tiles”. Previous research has shown that N fertilizer management alone is not sufficient for reducing NO3 concentrations in subsurface drainage to acceptable levels, therefore additional approaches need to be devised. We compared effectiveness of oat and rye cover crops for reducing NO3 concentration and load in subsurface drainage water for a no-till corn (Zea mays L.)-soybean (Glycine max [L.] Merr.) management system. A winter rye (Secale cereale L.) cover crop was drilled after harvest over the entire plot area each year and then chemically killed before planting the following spring. A spring oat (Avena sativa L.) cover crop was broadcast seeded into the standing corn and soybean crops near physiological maturity. The oat cover crop treatment winter-killed and did not need to killed in the spring. Twelve 30.5 x 42.7-m subsurface-drained field plots were established in 1999 with an automated system for measuring tile flow and collecting flow-weighted samples. The rye treatment and a control were initiated in 2000, the oat treatment was initiated in fall 2005, and all treatments were replicated four times. Both the rye and oat cover crop treatments reduced drainage water flow-weighted NO3 concentrations and load in each year between 2006 and 2010. Averaged over 5 yr the rye cover crop reduced flow-weighted NO3 concentrations by 48% and loads by 46%. The oat cover crop reduced flow-weighted NO3 concentrations by 25% and loads by 37%. A rye or oat cover crop grown after both corn and soybean have the potential to reduce the NO3 loads delivered to surface waters by subsurface drainage systems.