Effect of diversified cropping system on weed phytosociology

Abstract

The crops like Rice, Finger millet, Black gram and Horse gram were grown as sole crops and as mixed crops in all four paired combinations in 1:1 ratio (i.e., Rice + Black gram, Rice + Horse gram, Finger millet + Black gram and Finger millet + Horse gram) as treatments to estimate the effects on weed biomass and diversity and on systems’ effectiveness. The study showed that, there were significant differences between different treatments in respect of total grain yield of target crops and weed diversity parameters. Significantly higher grain yield in cropping system was recorded in Finger millet (3.72 t ha-1) as sole crop followed by Finger millet + Black gram (3.11 t ha-1) and Finger millet + Horse gram (3.11 t ha-1) as mixed crop and the lowest grain yield was recorded in Rice (1.30 t ha-1) as sole crop. Compared to sole crops, weed biomass was significantly reduced by mixed crops of Finger millet + Black gram (0.20 t ha-1) and Finger millet + Horse gram (0.30 t ha-1). The correlation between total grain yield of cultivated crop and dry weed biomass (R= -0.860) or species richness (R= -0.319) or basal area of weeds (R = -0.518) or weed density (R= -0.567) and between Rice equivalent yield of different cropping systems and associated dry weed biomass (R= -0.468) showed that mixed cropping systems have higher natural capacity to control weeds. Among all the treatments, Finger millet + Black gram was found to be the best followed by Finger millet + Horse gram cropping system for controlling weed biomass and diversity, both naturally and biologically.