Cereal Rye (Secale cereale L.) Fall Planting Date to Determine Cover Crop Biomass Production in the US Midwest.

Cereal rye (Secale cereale L) is the most common used cover crop in the United States Midwest because of its wide-range of adaptation and ability to be established late in the fall, overwinter, and grow again in the spring. The potential benefits from cereal rye depend in large part on the amount of biomass that can be produced during the fallow periods of a crop rotation. The general assumption is that increased biomass production is strongly correlated with the potential benefits. The cereal rye growing season in the fall is limited in the Midwest by cold temperatures and short days after the primary crop is harvested. We hypothesized that earlier fall planting dates of cereal rye may improve the establishment of plants prior to winter and thus provide greater biomass production in the spring. This study was established in Eastern -rainfed- and South Central -irrigated- Nebraska during the 2015 and 2016 growing seasons. Four cover crop planting dates (02 Oct., 09 Oct., 12 Oct., and 21 Oct.) were compared during 2015 and six to eight planting dates (weekly plantings from early Sept. to early Nov) during 2016 after corn harvest. Both fall and spring cereal rye biomass were affected by planting date, with the highest production occurring at the earliest planting date. At both samplings, a positive linear relation was confirmed between biomass production and temperature, measured by growing degree days. However, variations in cereal rye biomass production from different planting dates were not fully explained by variations in temperature. Including cereal rye as an overwintering cover crop did not affect subsequent soybean in spite of the differences in the cereal rye biomass production.