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Cover Crop Introduction into Corn (Zea mays L.)-Soybean (Glycine max L.) Cropping Systems
Fall-seeded cover crops are limited by the short growing season remaining between harvest and planting the succeeding crop. To address this challenge, we considered two alternative systems for introducing cover crops into corn (Zea mays L.)- soybean (Glycine max L.) cropping systems. The first alternative was to interseed the cover crops species with corn at specific developmental stages. We evaluated the effect on corn, cover crop biomass, and the subsequent soybean crop. No detrimental effects on corn were found when cover crops were interseeded at or after corn canopy closure due to the limited cover crop biomass produced during the growing season. However, corn was negatively affected with cover crops interseed at corn planting. Cover crops interseeded at canopy closure did not establish due to corn canopy shading. Cover crops interseeded at or after R5 (dent) produced greater biomass the following spring than in the fall, and cover crops interseeded at R5 and R6 (physiological maturity) produced greater biomass than cover crops interseeded at corn harvest. This indicated that the interseeding by broadcasting cover crops can be successful for improving biomass production. The second alternative was to modify corn management practices such as planting date, plant population, and comparative corn relative maturity (CRM) to allow earlier cover crop seeding dates. We attempted to understand the impact on corn yield, cover crop biomass production, and the subsequent soybean crop. Early- and early-to-medium-maturity hybrids allowed corn harvest about one month earlier and medium-maturity hybrids about 15 d earlier than late-maturity hybrids. No differences in corn yield were observed between the medium- and late-maturity hybrids planted at the earlier planting date, with a 107 CRM hybrid planted early having the highest yield of 16.0 Mg ha-1. The greatest cover crop biomass production occurred with the earliest cover crop planting date. Cover crop biomass increased with air temperature, which was measured with growing degree days (GDDC). This indicates that changes in planting date and corn CRM hybrids are important to increase the potential for use of cover crops. The subsequent soybean yield was not affected by cover crops in either alternative.
Bastidas, Angela M, "Cover Crop Introduction into Corn (Zea mays L.)-Soybean (Glycine max L.) Cropping Systems" (2018). ETD collection for University of Nebraska - Lincoln. AAI10689134.