text: Allelochemicals are a useful tool in sustainable farming due to their ability to control weeds. The possible application of allelopathy in agriculture is the subject of much research. Using allelochemical producing plants in agriculture results in significant suppression of weeds and various pests. Some plants will even reduce the germination rate of other plants by 50%. Current research is focused on the effects of weeds on crops, crops on weeds, and crops on crops.  This research furthers the possibility of using allelochemicals as growth regulators and natural herbicides, to promote sustainable agriculture. Agricultural practices may be enhanced through the utilization of allelochemical producing plants. When used correctly, these plants can provide pesticide, herbicide, and antimicrobial qualities to crops. number of such allelochemicals are commercially available or in the process of large-scale manufacture.  For example, leptospermone is an allelochemical in lemon bottlebrush (Callistemon citrinus). Although it was found to be too weak as a  commercial herbicide, a chemical analog of it, mesotrione (tradename Callisto), was found to be effective. It is sold to control broadleaf weeds in corn but also seems to be an effective control for crabgrass in lawns. Sheeja (1993) reported the allelopathic interaction of the weeds Chromolaena odorata (Eupatorium odoratum) and Lantana camara on selected major crops.
  Many crop cultivars show strong allelopathic properties, of which rice (Oryza sativa) has been most studied. Rice allelopathy depends on variety and origin: Japonica rice is more allelopathic than Indica and Japonica-Indica hybrid. More recently, critical review on rice allelopathy and the possibility for weed management reported that allelopathic characteristics in rice are quantitatively inherited and several allelopathy-involved traits have been identified. The use of allelochemicals in agriculture provide for a more environmentally friendly approach to weed control, as they do not leave behind residues. Currently used pesticides and herbicides leak into waterways and result in unsafe water qualities. This problem could be eliminated or significantly reduced by using allelochemicals instead of harsh herbicides. The use of cover crops also results in less soil erosion and lessens the need for nitrogen heavy fertilizers.