Investigation of the effects of non-living mulches and metribuzin on redroot pigweed and lamb'squarters in tomato

ABSTRACT-A field study was conducted to determine the influences of six mulch materials (organic and inorganic), including black plastic, transparent plastic, wheat straw, peat moss, coco peat, and sawdust and the metribuzin on the two weed species vegetative and reproductive growth cycles in a tomato field using a randomized complete block design with three replications at the Research Station of the Agricultural School, Shiraz University, Shiraz, Iran. According to the results of the analysis of variance, all evaluated traits of both weed species, and also tomato, were significantly influenced by treatments at p < 0.01.The longest and shortest time of redroot pigweed (Amaranthus retroflexus L.) emergence were recorded under the plastic mulch treatments at 28 days after transplanting (DAT) and organic mulches as well as metribuzin at 21 DAT, respectively. Plastic mulches deferred the time of lamb's quarters (Chenopodium album L.) emergence more than organic mulches up to 28.0%. Additionally, the longest time of lamb'squarters emergence was observed with coco peat at 29 DAT and the shortest time of its emergence was recorded under the application of clear plastic and sawdust mulches at 23.3 DAT. Results showed that, the highest marketable tomato yield (up to 19.2 kg m-2) was assessed in covered plots with black plastic mulch, while the lowest marketable yield was detected by 3.02 kg m-2 in the plots under the application of the sawdust treatment. In general, results demonstrated that the plastic mulches, particularly the black plastic sheet, could be reliable alternatives for metribuzin to control weed infestations in tomato fields.