Effects of alfalfa sowing rate and planting methods on weeds population dynamic in establishment year

Abstract:It has been hypothesized that increased sowing rate and different planting methods can increase weed suppression and thereby play a role in weed management. To assess the Effects of alfalfa sowing rate and planting methods on weeds population dynamic, field experiment was conducted in 2008 at the College of Agriculture in Shiraz University. The experimental design was a randomized complete block with four replicates in a factorial arrangement of the treatments and two factor were the planting methods (Furrow planting, Broadcasting, Row planting, and Raised bed planting) and alfalfa sowing rates (5, 10, 15, and 20 kg seed ha-1). Five weed species was identified by studying weed population which were mainly annual broad-leaves species. In this study, the interaction of planting methods and sowing rates on frequency percentage of Chenopodium album was different significantly. But, Alfalfa planting methods had no significant effect on weeds frequency percentage. In contrast, the effect of alfalfa sowing rates on frequency percentage of Amaranthus retroflexus and Stellaria media was significant. Results indicated that alfalfa sowing rates reduced weed frequency percentage. The effect of alfalfa sowing rates on relation density percentage (RDP) of Amaranthus retroflexus was also significant. Thus, the maximum RDP of A. retroflexus was obtained in alfalfa by 20 kg seed ha-1.