Simply put, allelopathy refers to an ecological phenomenon of plant-plant interference through release of organic chemicals (allelochemicals) in the environment. These chemicals can be directly and continuously released by the donor plants in their immediate environment as volatiles in the air or root exudates in soil or they can be the microbial degradation products of plant residues. The chemicals may interfere with survival and growth of neighboring or succeeding plants. Black walnut, eucalyptus, sunflower, sorghum, sesame and alfalfa are common examples of plants with allelopathic...