Producers are interested in growing cover crops and reducing fallow. Growing a crop during the fallow period would increase profitability if crop benefits exceeded expenses. Benefits of growing a cover crop have been shown in high-rainfall areas, but limited information is available on growing cover crops in place of fallow in the semiarid Great Plains. A study from 2007–2014 evaluated cover crops, annual forages, and short-season grain crops grown in place of fallow. In the first experiment (2007–2012), the rotation was no-till wheat-fallow, and in the second experiment (2012–2014), the rotation was no-till wheat-grain sorghum-fallow. Wheat yield was affected by the previous crop, but growing a previous crop as hay or cover did not affect wheat yield. Wheat yield following the previous crop was dependent on precipitation during fallow and the growing season. In dry years (2011–2013), growing a crop during the fallow period reduced wheat yields, whereas growing a crop during the fallow period had little impact on wheat yield in wet years (2008–2010). The length of the fallow period also affected yields of the following wheat crop. Growing a cover or hay crop until June 1 affected wheat less than if continuous wheat, grain pea, or safflower were grown until grain harvest, which was approximately the first week of July. Cover crops did not improve wheat yield. Winter and spring lentil had the least negative impact on wheat yield, and yielded similar to fallow when averaged across years. Winter cover crop treatments tended to reduce yield more than spring cover crop treatments, which was due to less soil moisture available at wheat planting following winter cover crop compared with spring cover crop treatments. To be successful, the benefits of growing a cover crop during the fallow period must be greater than the expense of growing it; plus compensate for any negative yield impacts on the subsequent crop. Cover crops always resulted in less profit than fallow, whereas annual forages and grain peas often increased profit compared with fallow. The negative effects on wheat yields might be minimized with flex-fallow, which is the process of only growing a crop in place of fallow in years when there is ample soil moisture at the time of making the decision to plant.
Soil Science Society of America
Professional Meetings: 1.00
American Society of Agronomy
Soil and Water Management : 0.50
Crop Management : 0.50
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