Influence of organic weed management practices on floristic diversity and shifts in maize –pea cropping system

Abstract

Studies on weed flora changes were carried out in a long-term experiment in maize - peas cropping system under All India Coordinated Research Project on Weed Management (AICRP-WM) during October 2019 to September 2021 at Palampur. Ten weed control treatments viz. T -hoeing, T -stale seed bed + hoeing, T -raised 1 2 3 -1 stale seed bed + hoeing, T -mulch 5t ha , T -stale seed bed + mulch, T - raised stale seed bed + mulch, T - 4 5 6 7 intercropping (soybean in kharif and fenugreek in rabi), T -crop rotation (alternating soybean - mustard with 8 maize - peas), T -intensive cropping (additional crops of mustard in autumn and buckwheat in summer) and 9 T -chemical check (pendimethalin in rabi and atrazine in kharif) were evaluated for weed flora composition 10 and shifts in maize-peas cropping system. The weed flora were comprised of 14 species in rabi 2019-20 and 11 in -1’ -1 rabi 2020-21.’Raised stale seed bed + hoeing’and ‘mulch 5t ha in 2019 and ‘mulch 5t ha ’in 2020 were having highest number of weed species. In kharif 2019, the weed flora were comprised of 8 weed species and, in kharif -1’ 2021,14 species.‘Mulch 5t ha was having highest weed species in both seasons. There was considerable change in weed species compositions during the second year as compared to the first year. In rabi 2019-20, Vicia sativa (13%) and Tulipa asiatica (12%) and in rabi 2020-21, Tulipa asiatica (21%) and Spergula arvensis (15%) were the dominant weed species. In kharif 2020, Cyperus sp. (17%), Echinochloa colona, Polygonum alatum and Ageratum conyzoides 15% each, in kharif 2021 Cyperussp. (16%), Ageratum conyzoides(15%) and Commelina benghalensis (14%) were dominant. The Simpson’s index of diversity was highest under‘ mulch 5t ha  -1 + hand weeding’and lowest under ‘chemical check’in all the seasons.