Avtar Singh, Raminder Kaur, J.S.Kang and Gurpreet Singh
The rice-wheat cropping system is the most important agricultural production system in Indo Gangetic Plains in India. The productivity of this system is declining after 1990’s. The weeds are the major problem in the productivity of this system. In rice-wheat cropping system, the menace of Phalaris minor in wheat has threatened the productivity of wheat crop. Yield losses especially from Phalaris minor alone are estimated from 25 to 50 per cent and, under very severe infestations, the losses may go up to 80 per cent. Rice crop management system supports the survival of Phalaris. minor seed in rice-wheat system. The major weeds in rice are Echnichola spp., Digitaria sanguinalis, Commelina benghalensis, Celosia argentia, Cyperus rotundus, Cyperus iria and Cyperus rotundus . Weeds in wheat show resistance to isoproturon and cross resistance to the other herbicides. The rate of resistance evolution depends on the soil seed bank dynamics and selection intensity, with selection intensity having the greatest impact. The study of the weed dynamic in rice-wheat cropping system helps the researchers and farmers to formulate the strategies for the control of weeds. In this chapter has discussed the impact of weeds, weed seed bank, various management practices for control of weeds. Weed dynamic can be controlled effectively by the conservation tillage which includes crop rotation, cover crops and reduced tillage.