Nitrogen cycling and N credits from cover crops to sugarbeet
Sugarbeet (Beta vulgaris L.) is valuable crop in North Dakota, but it leaves the soil uncovered after harvest decreasing soil health. The lack soil coverage during the winter increases soil losses due to wind erosion. In addition to that, high levels of residual deep nitrogen after cereal production can decrease sugar yield in sugarbeet. Cover crops provide soil coverage, preventing soil erosion, and reducing NO3-N leaching. The experiment was conducted at two locations, Prosper and Hickson at ND, from April to November of 2017. The experimental design used was a RCBD with four replicates. The cover crops were radish, winter camelina winter wheat (Triticum aestivum L.), oat (Avena sativa L.), winter rye, and a check plot (without cover crop), established into spring wheat residue in August. Biomass production across locations was 2.2 Mg ha-1 in both radish and oat Soil cover in oat and radish was 70% and 57% in rye with all cover crops providing important soil protection from wind erosion. Nitrogen, P, and total ash content were significantly higher in oat and radish than in rye biomass. Soil NO3-N, after growing season, was significantly higher in the check plots (25.9 kg ha-1) than in plots with a cover crop; oat (12.3 kg ha-1), winter rye (13.2 kg ha-1) and radish (16 kg ha-1).This indicates cover crops are scavenging residual NO3-N and keeping it in their biomass, preventing it from potential leaching and run-off. In conclusion, radish, winter rye, and oat provided soil cover protecting the soil from erosion and reduced soil residual NO3-N prone to leaching.