Crop residues, which release allelochemicals during decomposition may be able to suppress weed growth. In this study, experiments were conducted to assess the ability of crop residues of 40 commonly cultivated improved rice varieties in Sri Lanka (Oryza sativa L.) to suppress the seed germination and growth of barnyard grass (Echinochloa crus-galli). Rice crop residues were incorporated with silica sand in small pots and the experiment was conducted under greenhouse conditions. Rice cultivars exhibited marked differences in the inhibition of growth and development of barnyard grass. Ld (Labuduwa) and Bw (Bombuwela) rice varieties exhibited the highest inhibitory activity on the seedling growth of barnyard grass, reducing the dry weight by more than 60%, while incorporation of Bw364 rice residue with sand exhibited the highest average inhibition (44.8%) on barnyard grass seed germination and seedling growth. Ld355, Ld368 and Bw400 reduced barnyard grass seed germination and growth by more than 40%. These results suggest that there is a genetic variation among the rice varieties for their ability to reduce weed germination and weed growth in paddy fields, but further analysis of allelopathic characters of rice needs to be conducted.
Wathugala, D. L., & Ranagalage, A. S. (2015). Effect of incorporating the residues of Sri Lankan improved rice (Oryza sativa L.) varieties on germination and growth of barnyard grass (Echinochloa crus-galli). Journal of the National Science Foundation of Sri Lanka, 43(1), 57–64. https://doi.org/10.4038/jnsfsr.v43i1.7915