Weed control efficacy of combined application of grass pea and mustard crop residues in T. aman rice

Abstract

Among different methods of weed control, allelopathy could lead to reduced labor costs and increased efficiency, without any adverse effects on the environment. In this regard, an experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the allelopathic potential of grass pea and mustard crop residues on weed suppression and crop performance of transplanted aman rice. The experiment consisted of three cultivars of T. aman rice viz., Binadhan-7, BRRI dhan49 and BR11 and five different level of crop residues such as no use of crop residues, grass pea crop residues @ 2.5 t ha-1, mustard crop residues @ 2.5 t ha-1, combined use of grass pea and mustard crop residues @ 1 t ha-1 of each and hand weeding. All crop residues applied in the experiment suppressed weed growth and inhibition at satisfactory level. The experiment was laid out in a randomized complete block design with three replications. Weed population, weed dry weight and percent inhibition of weed were not significantly influenced by the interaction effect of crop residues (grass pea and mustard) and cultivars. BR11 produced the highest grain and straw yield among the treatment combination. The highest numbers of tillers hill-1, numbers of grains panicle-1, 1000-grain weight, grain yield, straw yield were observed in hand weeding, followed by combined application of grass pea and mustard crop residues @ 1 t ha-1 of each treatment. The highest grain and straw yield (4.81 t ha-1 and 7.65 t ha-1) was observed in hand weeding along with variety BR11 and the second highest (4.19 t ha-1 and 7.36 t ha-1) was obtained from combined use of grass pea and mustard crop residues @ 1 t ha-1 of each. The results of this study indicate that hand weeding followed by combined application of grass pea and mustard crop residues @ 1 t ha-1 of each showed potential activity to suppress weed growth.