Location: Soil, Water & Air Resources ResearchTitle: Corn stover harvest, tillage, and cover crop effects on soil health indicators
|OBRYCKI, JOHN - Orise Fellow|
|BIRRELL, STUART - Iowa State University|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2018
Publication Date: 8/2/2018
Citation: Obrycki, J.F., Karlen, D.L., Cambardella, C.A., Kovar, J.L., Birrell, S.J. 2018. Corn stover harvest, tillage, and cover crop effects on soil health indicators. Soil Science Society of America Journal. 82(4):910-918. https://doi.org/10.2136/sssaj2017.12.0415.
Interpretive Summary: Harvesting corn residue can help producers manage fields and provide additional income when the stover is sold to animal or bio-product markets, but excessive stover removal increase soil erosion potential and can hasten soil degradation. This Central Iowa study used no-tillage and chisel plow methods and compared soil health indicators after five years of growing continuous corn and removing stover at three different rates. Overall, harvesting stover did not consistently impair soil functions, but an important soil organic matter fraction was reduced when stover was removed or the soil was tilled. Adding a cereal rye cover crop to the continuous corn improved nitrogen cycling. This research will be useful to producers, crop consultants, conservationists, bio-economy investors, and researchers interested in productivity, soil organic matter and nitrogen cycling.
Technical Abstract: Monitoring soil health indicators (SHI) will help ensure corn (Zea mays L.) stover harvest is sustainable. This study examines SHI changes after five years of growing continuous corn using either chisel plow or no-tillage practices and harvesting 0, ~35, or ~60% of the stover. Two no-tillage treatments with a cereal rye (Secale cereale L.) cover crop and stover harvest rates of ~35 or ~60% were also evaluated. All eight treatments were replicated four times in a randomized complete block design at an 11 ha site in Boone County, Iowa. Soil samples were collected following grain and stover harvest from 0 to 5- and 5 to 15-cm depth increments. Particulate organic matter carbon (POM-C) decreased when stover was removed or the soil was chisel plowed. No-till with 0% stover removal had 10 mg g-1 POM-C in the 0 to 5-cm soil layer, which was 1.9-fold higher than other treatments. Potentially mineralizable nitrogen (PMN) was greater in cover crop treatments. Average PMN values were 56.9 and 45.5 µg g-1 PMN for no-till with cereal rye at 0 to 5- and 5 to 15-cm depths, respectively, compared to 17.5 and -3.7 µg g-1 PMN for the same no-till treatments without cereal rye. Other soil properties did not respond to increasing levels of stover removal. At this location and at the studied removal rates, five years of harvesting corn stover did not consistently decrease soil health, but POM-C data suggest changes may be occurring. Long-term monitoring should continue and assess corn stover harvest sustainability.