Changes in the Weed Flora of Rice - Wheat Cropping System
Abstract
In transplanted rice, Scirpus spp. and Cyperus iria constituted more than 45 percent and 31 percent of total weed population, respectively. In muchch rice Echinochloa colona and Cyperus iria constituted more than 80 percent and 11 percent of total weed population, respectively during both the years. In wheat grown after transplanted rice, Phalaris minor and Alopecurus myosuroides constituted more than 82 percent weed population whereas Phalaris minor and Lolium temulentum constituted more than 72 percent of the weed population in wheat grown after mchch rice. The population of Scirpus spp. and cyperus iria reduced by 4.19 percent and 2.14 percent, respectively in transpianted rice. In muchch rice the proportion of Chinochloa colona and Cyperus iria increased by 1.15 percent and 5.34 percent, respectively over first year. The density of Phalaris minor and Alopecurus myosuroides incrcased by 5.58 percent and 1 40 percent, respectively. In wheat grown after muchch rice, the density of Phalarls minor increased by 8.91 percent and that of Vicia sativa and Avena fatua decreased by 5.08 and 4.38 percent, respectively, oyer first year.
