Improving yield and mineral nutrient concentration of potato tubers through cover cropping

Over-fertilization of food crops has resulted in increased environmental concerns over the past decades. On the other hand, literature indicates a decline in concentration of mineral nutrients in vegetables in the past 50 years. Thus, a need occurs to employ cropping systems that are less dependent on fertilization while maintaining yield and nutritive value of food crops. This study evaluated tuber yield and nutrient concentration of potatoes (Solanum tuberoswn L.) following rye (Secale cereale L.), forage radish (Raphanus sativus L.), winter pea (Pisum sativum L.) and no cover crops (NCC). Four nitrogen (N) fertilizer rates (0, 75, 150, and 225 kg N ha(-1)) were applied to a red-skinned potato cultivar (Dark Red Norland) and a buff-skinned one (Superior). Overall, potatoes grown after cover crops produced 13-25% more tubers compared to NCC. Potatoes following NCC needed to be fertilized at 225 kg N ha(-1) to produce the highest yield of 26.5 Mg ha(-1), whereas potatoes after winter pea or forage radish produced the same or higher yields (10-25%) at 75 or 150 kg N ha(-1) , respectively. Rye provided less N to a succeeding potato crop than forage radish or winter pea; however, potatoes following rye produced a greater yield than those planted after NCC. Potatoe tubers in cover crop plots accumulated more mineral nutrients compared to NCC; however, the differences among cover crops were not always significant. Overall, forage radish and winter pea were better alternatives to rye as indicated by less N fertilizer application, sustained tuber yield, and tuber mineral nutrient concentration.