Rice (Oryza sativa L.) is the staple food of Sri Lankans and one of the most widely grown food crops in Sri Lanka. In all rice ecosystems, use of herbicides has been the most common method in weed control. However, intensive and repeated application of herbicides has resulted in various environmental problems such as environmental pollution, herbicide resistant weeds (Valverde et al., 2000), residual effects on the crop, and the disappearance of susceptible weeds, which affects weed biodiversity (Itoh, 2000). In this regard, an alternative to high dependence on herbicides is needed. Such an alternative would be the use of allelopathy, that reduces herbicide use in rice cropping systems.
58 D.L. Wathugala & A.S. Ranagalage
March 2015 Journal of the National Science Foundation of Sri Lanka 43(1)
Allelopathy could be used for weed control in two ways; (1) selecting a suitable crop cultivar or incorporating allelopathic characters into a desired crop cultivar, and (2) applying the residues or straw as mulches, or growing an allelopathic cultivar in a rotational sequence (Rice, 1995).