Plant nutrient losses in runoff from conservation tillage corn |
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| Authors: | LL McDowell KC McGregor |
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| Institution: | United States Department of Agriculture, Agricultural Research Service, USDA Sedimentation Laboratory, P.O. Box 1157, Oxford, MS 38655, U.S.A. |
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| Abstract: | Conservation tillage in north Mississippi, U.S.A., reduced total (sum of solution and sediment) plant nutrient losses in runoff from corn, even though solution nitrogen (N) and phosphorus (P) concentrations in runoff were greater than from conventional-till and sediments were enriched severalfold in N and P. Plant nutrient losses were reduced by conservation tillage because of the significant reductions in soil loss. Soil losses from corn grown for grain were reduced more than 92% by reduced and no-till practices. Corresponding total losses of N and P were reduced about 70 and 80%, respectively.Conservation tillage reduced plant nutrient losses associated with sediments but increased solution P concentrations and losses in runoff. Solution P concentrations and losses, which were related to crop management, decreased in the following order: no-till corn (grain) ? no-till corn (silage) > reduced-till corn (grain) > conventional-till corn (grain) > conventional-till corn (silage). Solution P concentrations and losses in runoff increased with an increase in crop residues left on the soil surface after harvest and with a decrease in annual soil loss. |
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