Forage Radish and Winter Pea Cover Crops Outperformed Rye in a Potato Cropping System

Abstract

Core Ideas Forage radish and winter pea cover crops improved nitrogen‐use efficiency in a potato cropping system. A high N‐yielding winterkilled cover crop is preferred over rye for early planting of potato. Rye may not provide the succeeding potato with sufficient N because of early termination. Growers in the northeastern United States often over‐apply N fertilizer to guard against yield limitations. Over fertilization increases costs of production and raises environmental concerns. This study was conducted to evaluate whether using cover crops and N fertilizer management can improve tuber yield and nitrogen‐use efficiency (NUE) in a potato (Solanum tuberosum L.) production system. Three cover crop species including forage radish (Raphanus sativus L.), cereal rye (Secale cereale L.), and winter pea (Pisum sativum L.); four N fertilizer rates (0, 75, 150, and 225 kg N ha−1) and two potato varieties (Dark Red Norland [DRN] and Superior [SUP]) were used in a 2‐yr field experiment. Results indicated that tuber yield and NUE indices can be restricted by either the lowest or highest levels of N fertilizer (75 and 225 kg N ha−1, respectively). Potato grown in no cover crop plots needed to be fertilized at 225 kg N ha−1 to produce the highest yield (26.5 Mg ha−1) whereas potato after winter pea or forage radish produced the same or higher yields at 75 and 150 Kg N ha−1, respectively (P ≤ 0.01). Forage radish or winter pea improved NUE in either potato variety as more synchrony existed with respect to N release from cover crop residues and potato N requirements than that of cereal rye. Overall, forage radish or winter pea could be suitable alternatives to cereal rye in rotation with potato as indicated by the cover crop biomass production and N yield, N use metrics, and potato tuber yield.