Effect of Rice Residue Incorporation on Seed Germination and Seedling Growth of Weedy Rice (Oryza sativa var. spontanea)

Abstract

Weedy rice (Oryza sativa var. spontanea) is one of the most destructive weeds widely spread in rice-growing areas in Sri Lanka. However, suitable and effective control method has not yet been used to manage weedy rice in paddy fields. Incorporation of rice residue is recommended for sustainable rice farming in all rice growing countries. An experiment was conducted to examine the germination ability and growth performances of weedy rice with different amount of rice residue incorporation. Rice residues from different rice cultivars ie; BG359, LD365, BG407, AT401, BG358, AT362, AT402, BG450 and BG300, Herathbanda and Handiran were used. The experimental design used was RCBD with three replicates. Results revealed that there was a significant reduction of weedy rice seed germination, mean germination index and plant height due to incorporation of rice residue into sand compared to the control. However dry weight per plant did not show significant reduction. When increasing amount of residue incorporation, germination % and mean germination time also decreased. It is suggested that the inhibition of weedy rice seed germination observed in this study may be due to the activities of allelochemicals released by decaying residue.