Impact of Cover Crop Species Selection on Rainfed Corn Production in Western Nebraska.

Cover crops (CC) have increased in popularity across the United States. Producers in semi-arid regions such as Western Nebraska are questioning what CC species will be beneficial to incorporate in their cropping systems. Potential benefits of CC include increased soil holding capacity, increased soil organic matter, weed suppression, and improved soil fertility. However, in a water-limited environment, CC may use needed soil water, which may reduce yield of the subsequent corn crop. The objective of this study was to examine fall and spring biomass production of different CC species and how they impact subsequent soil moisture levels, and corn development and yield.

The trial was conducted in a randomized complete block design with four replications, at two locations in southwest Nebraska, North Platte and Grant. Treatments consisted of: 1) no CC 2) spring triticale 3) cereal rye 4) spring oat 5) purple top turnip 6) Siberian kale 7) balansa clover and 8) hairy vetch. Cover crops were drilled in the beginning of September following wheat harvest. Plots were 3.048 meters by 15.24 meters. CC biomass was collected in the fall of 2016 and spring of 2017 at both locations. CC at the North Platte location were terminated May 1st 2017, and corn was planted May 4th 2017. CC at the Grant location were terminated May 8th 2017, and corn was planted May 15th 2017. Subsequently, soil moisture readings were taken at 0-11 centimeter depth, and 11-20 centimeter depth biweekly starting around emergence. At the V6 corn growth stage, corn biomass was collected in both locations.

Initial findings illustrated noticeable differences in CC biomass in the fall of 2016. The Grant site CC biomass showed cereal rye being the highest amount of biomass, and balansa clover being the lowest amount of biomass. The North Platte site CC biomass showed Siberian kale being the highest amount of biomass and balansa clover being the lowest of biomass in North Platte. With spring 2016 CC biomass in both sites only four CC species produced measureable CC biomass. These species were: spring triticale, cereal rye, balansa clover, and hairy vetch. Soil moisture readings at plant stage illustrated differences between CC treatments thereby influencing water availability for the corn crop. The findings of this study will help guide the choices in CC species selection under rainfed cropping systems of semi-arid environments.