~ 677 ~ International Journal of Chemical Studies 2019; SP6: 677-683 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2019; SP6: 677-683 RS Pan ICAR-Research Complex for Eastern Region, FSRCHPR, Ranchi, Jharkhand, India Pradip Kumar Sarkar ICAR-Research Complex for Eastern Region, FSRCHPR, Ranchi, Jharkhand, India Reshma Shinde ICAR-Research Complex for Eastern Region, FSRCHPR, Ranchi, Jharkhand, India Rakesh Kumar ICAR-Research Complex for Eastern Region, Patna, Bihar, India JS Mishra ICAR-Research Complex for Eastern Region, Patna, Bihar, India AK Singh ICAR-Research Complex for Eastern Region, FSRCHPR, Ranchi, Jharkhand, India BP Bhatt ICAR-Research Complex for Eastern Region, Patna, Bihar, India Corresponding Author: RS Pan ICAR-Research Complex for Eastern Region, FSRCHPR, Ranchi, Jharkhand, India (Special Issue -6) 3 rd National Conference On PROMOTING & REINVIGORATING AGRI-HORTI, TECHNOLOGICAL INNOVATIONS [PRAGATI-2019] (14-15 December, 2019) Effect of diversified cropping system on weed phytosociology RS Pan, Pradip Kumar Sarkar, Reshma Shinde, Rakesh Kumar, JS Mishra, AK Singh and BP Bhatt 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. Keywords: Conventional practices, cropping system, yield, weed biomass and diversity Introduction In general, weeds that are associated with crops are exposed to many disruptive factors viz., climate, soil, topography, etc., which make their populations variable and dynamic nature over time (Booth et al. 2003) [4] . In case of responses to these causes of change, not all the species in an agricultural system are equally important but with differences in frequency, density, and growth habit making some species the principal ones which generate economic yield (Pitelli 2000) [22] , which warrants detailed studies in predominant cropping systems. One of the more utilized methods for the analysis of weed communities in cropping systems is the phytosociological study (Ige et al. 2008) [16] . A quantitative phytosociological study of a weed community in a defined area and time provides a momentary analysis of the plant composition, providing a tool that supplies various inferences for a plant community (Ferriol & Merle 2006; Pandey et al. 2011) [8, 21] , which can be approached with the description of their characteristics by employing tools such as similarity and diversity indices that clarify their performance. Ever since man began cultivating plants, he has to fight with weeds competing with crops for space, water, mineral nutrients and sunlight.