Effect of Weed Removal on Productivity of Chickpea (Cicer arietinum L.) and Lentil (Lens culinaris Med.) in a Mediterranean Environment

Three field experiments were conducted on chickpea ( Cicer arietinum L.) and four on lentil ( Lens culinaris Med.) at different winter-sown rainfed locations in Jordan from 1988/89 to 1990/91 to study the effect of the duration of weed-free and weed-infested conditions on yields and yield components of the crops. Chickpea seed yields were reduced on average by 81 % and straw yields by 63 % when fields remained weed infested until harvest compared with weed-free conditions throughout the growing season. The corresponding lentil seed and straw yield decreases were 63 % and 55 %. As the duration of weed-free period increased and the duration of weed-infested period decreased, yields increased. However, the critical period of weed interference was between 35 and 49 days after emergence in chickpea and between 49 and 56 days after emergence in lentil, when these crops were at an advanced stage of vegetative growth. There were significant negative correlations between the weed dry weight and the seed or straw yields. The reduction in seed yields in both crops because of weed interference occurred mainly through the reduced number of pods /plant, which in turn was partly the result of reduced number of secondary branches. In chickpea, some reduction also occurred through reduced 100-seed weight.