Impact of a Winter Rye Cover Crop on Edge-of-Field Nutrient Losses and Corn Silage Production.

Cover crops have the potential to reduce environmental impacts of corn production. The objective of this study was to quantify differences in nutrient loading between corn plots with or without a winter rye cover crop (Secale cerale). Four field plots (30 x 46 m) in Chazy, NY with edge-of-field monitoring were used for the study. Two plots were randomly assigned a rye cover crop treatment and were planted with a grain drill at a rate of 112 kg ha^-1 after corn silage harvest in 2015 and 2016. Continuous water flow was monitored from each hydrologic pathway during runoff events. Soluble reactive P (SRP), total P (TP), nitrate-N, total N (TN), and total suspended solids (TSS) were measured and multiplied by runoff volume to estimate nutrient export. In general, rye plots had lower nutrient loss compared to control plots. Cumulative loads for nitrate-N and TN were 1.0 and 1.2-fold greater for control plots, respectively (28.8 vs. 29.3kg nitrate-N ha^-1 and 42.0 vs. 51.7 kg TN ha^-1). Cumulative TP and SRP loads were 1.8 and 2.0-fold greater from control plots, respectively compared to rye plots (2.6 vs. 4.6 kg TP ha^-1 and 2.0 vs. 4.0 kg SRP ha^-1). Total and SRP loads in surface runoff were 4-fold lower for rye plots and TSS load in surface runoff was approximately 0.8-fold lower for rye plots. The impact of rye on tile drainage water quality was less clear. Results suggest that a winter rye cover crop was effective at reducing erosion and P transport in surface water runoff as compared to corn silage left fallow after harvest.