WEED DYNAMICS IN WHEAT-CANOLA INTERCROPPING SYSTEMS

Weeds cause huge losses due to their competition with crops. Intercropping of wheat ( Triticum aestivum L.) with canola ( Brassica napus L.) under different spatial arrangements was evaluated for their effects on weeds and interaction between the crops at the Agronomic Research Area, University of Agriculture, Faisalabad, Pakistan, during 2009-2010. The treatments included wheat (line sowing), canola (line sowing), wheat (broadcast method), one row of wheat + one row of canola (30 cm apart), two rows of wheat + two rows of canola (45 cm apart), four rows of wheat + four rows of canola (75 cm apart) and mixed cropping of wheat + canola (broadcast method). The results revealed that all intercropping treatments significantly affected weed density and dry weight over component sole crop of wheat. Mixed cropping of wheat + canola suppressed dry weight of Phalaris minor Retz., Chenopodium album L., Rumex dentatus L., and Coronopus didymus L. by 94, 77.2, 77.4, and 92%, respectively, over sole crop of wheat. The other intercropping treatments like one row of wheat + one row of canola, two rows of wheat + two rows of canola, and four rows of wheat + four rows of canola generally suppressed total dry weight of weeds by 81, 74, and 76%, respectively. Four rows of wheat + four rows of canola gave the highest land-equivalent ratios 1.37 and net benefit Rs 93 543 followed by two rows of wheat + two rows of canola. It is suggested that wheat-canola intercropping system in agro ecological conditions of Faisalabad could enhance landequivalent ratio > 1 (over-yielding) by suppressing weeds