RESUMEN
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.