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United States Department of Agriculture

Agricultural Research Service

Title: Soybean N Contribution for Corn in the Western Corn Belt

Author
item Varvel, Gary

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2001
Publication Date: November 1, 2001
Citation: VARVEL, G.E. SOYBEAN N CONTRIBUTION FOR CORN IN THE WESTERN CORN BELT. AGRONOMY ABSTRACTS #85720. 2001.

Interpretive Summary: Information on the N contribution from legumes, especially soybean, is needed to make decisions about the correct amount of N fertilizer to apply for the following corn crop in most areas of the Corn Belt. Corn yield data from two long-term crop rotation studies with both continuous corn and soybean/corn cropping systems with several N fertilizer rates provides an excellent database with which to make this determination. Sixteen years of data from a rainfed experiment and ten years of data from an irrigated experiment in the Western Corn Belt were used. Analyses of data from both experiments indicated soybean had supplied between 65 and 70 kg/ha to the following corn crop. This result was consistent between both experiments, rainfed or irrigated. Small variations occurred from year to year, but they were not related to grain yield of the previous soybean crop as we had originally presumed. There was also no difference between the results from the rainfed and irrigated experiments, which also were unexpected. Based on these results, we recommend that if corn is grown in a two-year rotation with corn that it be credited with supplying 60 to 70 kg/ha for the following corn crop.

Technical Abstract: Information on the N contribution from legumes, especially soybean, is needed to make decisions about the correct amount of N fertilizer to apply for the following corn crop in most areas of the Corn Belt. Corn yield data from two long-term crop rotation studies with both continuous corn and soybean/corn cropping systems with several N fertilizer rates provides an excellent database with which to make this determination. Sixteen years of data from a rainfed experiment and ten years of data from an irrigated experiment in the Western Corn Belt were used. Analyses of data from both experiments indicated soybean had supplied between 65 and 70 kg/ha to the following corn crop. This result was consistent between both experiments, rainfed or irrigated. Small variations occurred from year to year, but they were not related to grain yield of the previous soybean crop as we had originally presumed. There was also no difference between the results from the rainfed and irrigated experiments, which also were unexpected. Based on these results, we recommend that if corn is grown in a two-year rotation with corn that it be credited with supplying 60 to 70 kg/ha for the following corn crop.

Last Modified: 11/28/2014
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