Crop Rotation Affects Corn, Grain Sorghum, and Soybean Yields and Nitrogen Recovery

Abstract

Long‐term cropping system and fertilizer N studies are essential to understanding production potential and yield stability of corn (Zea mays L.), grain sorghum [Sorghum bicolor (L.) Moench], and soybean [Glycine max (L.) Merr.] in rain‐fed environments. A no‐till experiment (2007–2013) was conducted in eastern Nebraska to evaluate crop rotation (continuous corn, continuous grain sorghum, continuous soybean, corn–soybean, grain sorghum–soybean, corn–soybean–grain sorghum–oat [Avena sativa (L.)]/clover mixture [80% Melilotus officinalis Lam. + 20% Trifolium pretense L.], and corn–oat/clover–grain sorghum–soybean) and fertilizer N (corn and grain sorghum: 0, 90, 180 kg N ha−1; soybean and oat/clover: 0, 36, 67 kg N ha−1) on grain yield, plant N uptake, and N recovery efficiency. Diversified crop rotations increased corn and grain sorghum yields and improved yield stability. A positive corn grain yield response to fertilizer N was consistent across crop rotations, but fertilizer N addition with corn–soybean–grain sorghum–oat did not increase grain sorghum yield. Yield stability of soybean was less sensitive to management; all treatment combinations were found to be stable. Fertilizer N addition decreased soybean grain yield in 2 of 7 yr, but yields were similar in the remaining 5 yr. These results indicate that adoption of 2‐ and 4‐yr crop rotations in rain‐fed environments can result in high‐yielding, more stable corn, grain sorghum, and soybean grain production compared with shorter rotations or continuous cropping.Core Ideas Diversified 2‐ and 4‐yr crop rotations increased corn and grain sorghum yields. Corn and grain sorghum grain yields in 2‐ and 4‐yr rotations were more resilient to variable growing conditions. Soybean was less sensitive than corn and grain sorghum to crop rotation.