Vegetation Management and Interrill Erosion in No-Till Corn Following Alfalfa
- A. V. Gallagher ,
- N. C. Wollenhaupt and
- A. H. Bosworth
No-till corn (Zea mays L.) following alfalfa (Medicago sativa L.) is recommended for reducing soil erosion; however, killing alfalfa in the fall may result in insufficient crop residue cover for Conservation Compliance soil erosion goals. We hypothesized that soil conservation effectiveness was related to burn-down spray date and final harvest date influence on cover. A Wisconsin field study to test this hypothesis included fall and spring burn-down spray dates in combination with either August or September final alfalfa harvests. Soils included Plano and Saybrook silt loams (fine-silty, mixed, mesic Typic Argiudolls) on 2 to 9% slopes and Palsgrove silt loam (fine-silty, mixed, mesic Typic Hapludalf) and Reedsburg silt loam (fine-silty, mixed, mesic Aquic Paleudalf) on 7 to 14% slopes. Simulated rainfall (72 mm h−1 for 1 h) was applied following corn planting. The fall spray-September harvest (FS-SH) averaged 25% residue cover, measured after planting, with soil loss of 257 g m−2. The spring spray-August harvest (SS-AH) averaged 79% residue cover and 24 g m−2 soil loss. Of the 72 mm of rain applied on each of the treatments, 34 mm ran off the two FS treatments, 23 mm ran off the SS-SH treatments, and 19 mm ran off the SS-AH treatments. Treatment runoff amounts and final infiltration rates related in part to surface macroporosity and surface sealing. Fall herbicide application resulted in too little residue cover to adequately reduce soil erosion.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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