Effect of Tillage on Residual Nitrogen Availability From Alfalfa to Succeeding Corn Crops1
- A. Levin,
- D. B. Beegle and
- R. H. Fox2
It has been shown that there are significant differences in the potential rate of mineralization and nitrification between conventional and no-till soils. However, the practical effect of this difference on the availability of residual N from a legume and yield of a succeeding corn crop is unclear. Two field experiments in which corn (Zea mays L.) followed alfalfa (Medicago sativa L.) were conducted on a Hagerstown silt loam (fine, mixed, mesic Typic Hapludult) and on a Gilpin channery silt loam (fine-loamy, mixed, mesic Typic Hapludult) to determine the effect of no-tillage (NT) and conventional tillage (CT) methods on residual N availability from the legume as measured by yield and N uptake of the succeeding corn crop. Five rates of N (0, 45, 90, 135, and 180 kg ha−1) as ammonium nitrate were surface applied as either at-planting or sidedress applications. The mean soil N-supplying capability was 126 kg N ha−1 at both sites. There was no interaction between tillage method and N response, indicating that the fertilizer N recommendations for firstyear corn following alfalfa should be similar for NT and CT methods. Optimum economic grain yields for first-year corn resulted with the application of 83 and 88 kg N ha ' for the NT and CT treatments, respectively, at one site and with no added N at a second site, confirming this conclusion. The experiment was repeated for the second year at one site and the results for the second year also indicated that there was no difference in N fertilizer response due to tillage and no interaction between tillage and N response. Again this would indicate that N recommendations should be similar for the two tillage systems. There was no yield response to time of N application.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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