Author
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Teasdale, John |
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Shirley, Daniel |
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Submitted to: Journal of Production Agriculture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/1/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Hairy vetch is a winter annual legume that can improve soils, provide nitrogen for subsequent crop growth, and suppress weeds. A program has been developed at the Beltsville Agriculture Research Center for planting corn into live hairy vetch and managing vetch and weeds with herbicides applied after planting when needed. Experiments were conducted on large plots in production fields to contrast this postemergence system for managing no-tillage corn production in a hairy vetch cover crop with a conventional system requiring more herbicide and nitrogen fertilizer. In experiments on heavier soils, the reduced-input system with postemergence-only herbicides and reduced fertilizer nitrogen provided yields similar to the conventional system. However, on sandy soils, the conventional system provided optimum yields. Therefore, the reduced-input system is riskier but can maintain production and reduce costs and unnecessary inputs into the environment under selected soil conditions. These results will aid farmers and extension personnel to identify optimum corn production practices for their areas. Technical Abstract: The time of killing a hairy vetch (Vicia villosa Roth) cover crop relative to planting no-tillage corn (Zea mays L.) is critical to optimizing the benefits derived from the cover crop mulch. This research was conducted to determine the optimum timing for herbicide application in large-scale plots on production fields at Beltsville, MD. Four experiments were conducted over three years; two experiments on silt loam soils and two on sandy soil (fine sandy loam and loamy sand). Herbicides were applied 1) 1 to 3 weeks before planting corn (preplant), 2) immediately after planting corn (preemergence), or 3) after corn emergence (postemergence). Herbicide plots were split by N sidedressing at 0 or 80 lb/acre. Biomass of hairy vetch increased by an average of 1620 lb/acre and N content increased by an average of 44 lb/acre between the preplant and preemergence application dates but little change occurred between the preemergence and postemergence eapplication dates. Despite differences in N availability between herbicid treatment dates there was no significant interaction between herbicide and N sidedressing for corn yield suggesting that herbicide treatment did not change corn N requirement. On the silt loam soils, sidedressing N did not improve corn yield and there were no differences between herbicide treatments except for a slight yield decrease in the postemergence treatment in one year. On the sandy soils, sidedressing N improved corn yield and the postemergence treatment decreased corn yield compared to the preplant treatment in both years. Results suggest that a reduced-input management approach to growing no-tillage corn in a hairy vetch cover crop without additional N and with a postemergence-only herbicide program is risky but may be viable on heavier soils. |
