Long‐Term Corn Yield Impacted by Cropping Rotations and Bio‐Covers under No‐Tillage

Abstract

Cropping diversity and bio‐covers are perceived as integral components of conservation tillage because of increased pest control and soil organic matter. Consequently, effects of cropping sequences and bio‐covers on corn (Zea mays L.) yields were assessed. Main effects were 10 cropping sequences of corn, cotton (Gossypium hirsutum L.), and soybean (Glycine max L.) on a Loring silt loam (fine‐silty, mixed, thermic Oxyaquic Fragiudalf) at the Research and Education Center (REC) at Milan, and seven cropping sequences of corn and soybean at the Middle Tennessee REC on a Maury silt loam (fine, mixed, active, mesic Typic Paleudalf). Sequences were repeated in 4‐yr cycles (i.e., Phases I, II, and III) from 2002 to 2013. Strip‐plot bio‐covers consisted of hairy vetch (Vicia villosa L.), Austrian winter pea (Pisum sativum L. sativum var. arvense), wheat (Triticum aestivum L.), poultry litter, and fallow control. Across 12‐ yr, bio‐covers, and locations, continuous corn and yields from all rotations were equivalent (7.6 and 7.9 Mg ha−1, respectively; P = 0.07). However, among phase × sequence interactions, corn–soybean–corn–soybean rotation was highest yielding during Phase III (10.1 Mg ha−1), which was greater than continuous corn during all phases (P < 0.05). Bio‐covers, particularly poultry litter and hairy vetch, increased yields (across locations and years) when compared to wheat (P < 0.05). Incorporating soybean or cotton once within 4‐yr cropping cycles was equivalent to continuous corn (P > 0.05). However, including soybean and cotton twice increased yields by 6 and 7%, respectively (P < 0.05). Results suggest including two crops within a 4‐yr phase increases yields compared to continuous corn.Core Ideas Increasing cropping sequence diversity promotes greater yields when two species are included in a rotation compared to continuous corn. Including soybean and cotton twice increased yields by 6 and 7%, respectively. Bio‐covers, particularly poultry litter and hairy vetch, increased corn yields compared to wheat cover crops.