Impact of Long Term Integrated Plant Nutrient System (IPNS) in Rice –Wheat Cropping System on Population Dynamics and Dominance of Weed Species in Wheat

Weeds are the serious constraints in field crops. In 2014-15 and 2015-16 long term experiment was conducted which was earlier established from the year 1994 on IPNS in rice-wheat cropping system using randomized block design with four replications at Badiarkhar farm of the university. Twelve treatments viz., control (no fertilizer/manure), 50, 75 and 100% NPK each to rice and wheat through fertilizers, 50% NPK to rice and 100% NPK to wheat through fertilizers, 50% substitution of Nitrogen through FYM, wheat straw and green manure in rice and 100% NPK through fertilizers in wheat; 25% substitution of Nitrogen through FYM, wheat straw and green manure in rice and 75% NPK through fertilizers in wheat; and farmers’ practice (40% NPK through fertilizers to each crop plus 5 t FYM/ha on dry weight basis to rice) were evaluated for a period of two years (2014-15and 2015-16). Phalaris minor was the most dominant weed during both years followed by Alopecurus sp., Vicia sativa, Polygonum hydropiper, Lathyrus aphaca and Polygonum alatum. Artemisia sp. and other weeds had a little infestation during rabi 2014-15. While Cynodon dactylon, Anagallis arvensis, Centella asiatica and other weeds had shown their invasion during rabi 2015-16.