Many agricultural watersheds in Minnesota have toxic levels of phosphorus and nitrogen, much of which originates in agricultural fields that are fallowed from October through May. Autumn-sown winter cover crops can be used to retain these nutrients. Soil NO3-N levels and and quantities of N sequestered by winter rye (Secale cereale), Tillage Radish®(Raphanus sativus), and the oilseed crops, winter camelina (Camelina sativa), and pennycress (Thlaspi arvense) were evaluated in a relayed cover crop/soybean production system at three sites spanning the north-south climatic gradient of Minnesota.