Smothering effect of different crops on weed Malva neglecta Wallr.

Field study was conducted at experimental farm of Punjab Agricultural University ,Ludhiana (India) during rabi seasons of 2004-05 and 2005-06. The experiment was laid out in randomized block design with fourteen treatments having combination of seven different crops viz. bread wheat, durum wheat, six - rowed barley, two-rowed barley, raya, gobhi sarson, linseed and two weed control treatments i.e. hand weeded and unweeded. The study was planned with an objective to find out the most suitable Rabi crop that can suppress the weeds to maximum extent with minimum reduction in yield as there was no herbicide available which can control the weeds in an effective manner. Minimum weed dry matter accumulation was observed in raya (0.97qha-1 in the weeded plot) whereas maximum dry matter accumulation was observed in bread wheat (8.3qha-1), followed by durum wheat (6.1qha-1), linseed(5.0qha-1), barley (6-row) (4.9qha-1), barley (2-row) (2.6qha-1) and gobhi sarson (2.4qha-1). Raya (Brassica juncea) showed maximum suppressing poten-tial as minimum per cent reduction in crop yield of unweeded over weeded (7.4%) and minimum per cent increase in weed dry matter of unweeded over weeded( 44%) was observed in this crop. Gobhi sarson (Brassica napus) was the next best smothering crop followed by barley (2-row), barley (6-row), linseed, durum wheat and bread wheat, respectively in suppressing the M. neglecta. Two hand weedings treatment proved better in controlling the weeds as compared to unweeded treatment.