Intercropping vegetable species that serve a specific role in production — from weed suppression to soil fertility to growth habit — improve crop yields over the entire system compared to a monoculture crop, according to results of a Southern Sustainable Agriculture Research & Education-funded study. Jose Franco, a graduate student in the Department of Ecosystem Science and Management at Texas A&M University, along with Department of Horticultural Sciences professor Astrid Volder, manipulated functional species diversity in an organic intercropping system to determine whether a multilayered agroecosystem improves per-area yield. Franco said that the “three sisters” intercropping system of squash, beans and corn practiced by Native Americans is a perfect example of crops using functional elements to the benefit of the entire system. “The squash suppresses weed growth, the bean is a nitrogen-fixer, and the corn is used as structural support because it grows tall.” Franco chose okra as a pollinator attractant, peanuts and cowpea as nitrogen fixers, watermelon as a weed suppressor and hot pepper for its allelopathic benefits. Five treatments of intercropped plants, where each plant was incrementally added to the system, were compared to five mono-crop treatments over two years. The researchers found that, overall, crop yields increased on a per-acre basis in the intercropping systems compared to the mono-crop treatments, with the most noticeable increases in per-plant production in the watermelon-okra-peanut intercropping system. The researchers said that while some literature exists on companion planting, little information exists on using the functional diversity of plants in an intercropping system. So for farmers interested in trying out the technique, it’s going to take a bit of experimentation to find the right cropping combination. For more information on this research project visit SARE. This report is in the March 2014 issue of Acres U.S.A. magazine.