Cover Crops Benefits, Nitrogen Credits, and Yield Effects in Maize and Sugarbeet in the Northern Great Plains
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Abstract
Fall-seeded cover crops (CC) provide soil coverage that prevents soil erosion and reduces NO3-N leaching. It is believed N accumulated in CC biomass is available to the next crop. The main objective of this research is to determine if N in the CC biomass provides N to the next crop of maize (Zea mays L.) and sugarbeet (Beta vulgaris L.). Two experiments were conducted in Hickson and Prosper, ND from 2017-2019. Maize grain yield and quality and sugarbeet root yield and chemical composition of the root were evaluated after fall-seeded cover crops. Fall biomass was greater in radish (Raphanus sativus L.) and oat (Avena sativa L.) than the other cover crops evaluated. Likewise, in the sugarbeet experiment, the check treatment (no CC) contained greater soil NO3-N concentrations compared with all CC. Winter-hardy CC survived the winter and reduced gravimetric water content in the soil profile in comparison with winter-killed CC and the check. Winter camelina [Camelina sativa (L.) Crantz] and winter rye (Secale cereale L.) reduced maize grain yield compared with the check and other cover crop treatments. Winter camelina and winter wheat (Triticum aestivum L.) decreased sugarbeet stand establishment and root yield in Prosper and Hickson in 2018. The yield of both crops increased with increased N rate, but the N accumulated in the cover crops biomass did not make a difference in grain or root yield of either maize or sugarbeet, indicating there was no N cycling to the following crop in these experiments.