evaluation of the integrated weed management in seed alfalfa (medicago sativa l.)

this experiment was conducted for three consecutive years from 2000 to 2002 to evaluate the effects of integrated weed management on weeds of alfalfa at the safi abad agricultural research farm of dezful. the experimental design was a randomized complete block with strip-split plot arrangement of treatments. herbicide treatment was as horizontal factor at five levels which in 2000, consisted of application of bromoxynil at 0.45 kg ai /ha at the 2 - leaf stage of alfalfa + metribuzin at 0.35 kg ai /ha after the cutting for seed, application of bentazon at 0.96 kg ai/ha at the 6 - leaf stage of alfalfa + metribuzin at 0.52 kg ai/ha after the cutting for seed, application of bentazon at 0.96 kg ai /ha at the 6 - leaf stage of alfalfa + bentazon at 1.44 kg ai /ha after the cutting for seed, weed free and weedy checks. cultivation was as vertical factor at three levels which in 2000, consisted of reciprocal application of shovel cultivator and rolling + shovel cultivator when alfalfa was 30 cm tall and after the cutting for seed and noncultivated plot. in 2001 and 2002, treatments were applied after the cutting for seed and were as follows: application of metribuzin at 0.35 and 0.52 kg ai/ha, bentazon at 1.44 kg ai /ha, weed free and weedy checks, and cultivation treatments were as abovementioned treatments. in 2000, total number of broadleaved weeds were reduced by application of bromoxynil + metribuzin, bentazon + metribuzin and bentazon + bentazon by 77, 81 and 56%, respectively, and on average, by cultivation by 59%. in 2001, total number of broadleaved weeds were reduced by application of metribuzin at 0.35 and 0.52 kg ai/ha and bentazon by 83, 95 and 83%, respectively, and in 2002, by 68, 87 and 65%, respectively, by the aforementioned herbicide treatments. compared to the weedy check, alfalfa seed yield increase in application of metribuzin at 0.35 and 0.52 kg ai/ha, bentazon and weed free check treatmensts was 51, 11, 83 and 37%, respectively.