Influence of cover crops on arthropods, free-living nematodes, and yield in a succeeding no-till soybean crop

- Fall-planted cover crops have a stronger effect on below- than aboveground fauna.
- Planting winter cover crops can increase the complexity of the soil food web.
- Cereal and legume cover crops have different effects on the soil food web.

Production practices that incorporate fall-planted cover crops into no-till agronomic crop rotations have become increasingly popular across the Northeastern United States for weed suppression and enhancing environmental stewardship. Field experiments were conducted in 2011 and 2012 to investigate effects of rotating cereal (barley, Hordeum vulgare), legume (Austrian winter pea, Pisum sativum subsp. arvense), cereal/legume cover crop mixture, and a fallow (bare-ground) control on above- and belowground fauna in a succeeding soybean crop. Free-living nematodes and soybean foliar arthropods were sampled through time to determine effects of cover crops on soil food web structure and complexity and herbivorous and beneficial arthropods, respectively. Our hypotheses were that organic matter from cover crop biomass would provide energy and nutrients to the soil food web and that increased habitat complexity from cover crop residue would provide habitat for more predatory arthropods aboveground. In general, cover crops in this no-till system had a stronger influence on the below- than aboveground fauna. There was no consistent, positive effect of cover crops on beneficial foliar arthropods or on soybean yield. Cover crops increased the soil food web structure and complexity as determined by nematode community indices. Specific effects of different cover crop types on the free-living nematode community varied within the growing season and between study years. Probable causes for differences encountered among cover crop treatments and years are discussed.