Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 10, 2005
Publication Date: November 10, 2005
Citation: Kaspar, T.C., Jaynes, D.B., Parkin, T.B., Moorman, T.B. 2005. Effects of a rye cover crop and a permanent gamagrass strip on nitrate load in tile drainage [CD-ROM]. In: ASA-CSSA-SSSA Annual Meeting Abstracts. Nov. 6-10, 2005, Salt Lake City, UT. Technical Abstract: A significant portion of the nitrate from agricultural fields that contaminates surface waters in the Midwest cornbelt is transported to streams or rivers by subsurface drainage systems or “tiles”. Because previous research has shown that N fertilizer management alone is not sufficient for reducing nitrate concentrations in subsurface drainage to acceptable levels, additional approaches need to be devised. In this study we compared the effect of two cropping system modifications on nitrate load in tile drainage for a no-till corn-soybean management system. In one treatment, eastern gamagrass was grown in permanent 3.81 m wide strips above the tiles. For the second treatment, a rye winter cover crop was planted over the entire plot after soybean and corn harvest and then chemically killed before planting the following spring. Twelve 30.5 x 42.7-m tile-drained field plots were established in 1999 with an automated system for measuring tile flow and collecting flow-weighted samples. Both treatments and a control were replicated four times and established in 2000. Both the rye cover crop and the gamagrass treatments had poor establishment and grew slowly in the fall of 2000 because of dry conditions. Following a good cover crop establishment in 2001, 2002, 2003, and 2004 flow-weighted nitrate concentrations and loads for the rye cover crop treatment were significantly lower than the control in 2002, 2003, 2004, and 2005. Poor initial establishment and slow growth of the eastern gamagrass have limited the effectiveness of the gamagrass treatment, which did not have significantly lower nitrate concentrations or load than the control in any year. In 2003 and 2004, the gamagrass treatment, however, did lower total flow relative to the control.