Evaluation of efficiency of some soil-applied herbicides for weed control in chickpea (Cicer aretinum L.) and their residual effect on growth and grain yield of bread wheat (Triticum aestivum L.) in crop rotation under rainfed conditions

This study was conducted to evaluate the performance of different herbicides options for weed control in chickpea and their residual effect on bread wheat performance in crop rotation under rainfed conditions. The experimental design was randomized complete block with four replications conducted in Mahidasht Agricultural Research Center located in Kermanshah province, Iran during 2018-2019 and 2019-2020. The experimental treatments included: pre-plant sulfentrazone (Espartan 50% WP); 100 and 300 g.ha-1, pre-emergence sulfentrazone; 100 and 200 g.ha-1, pre-emergence pyroxasulfone (Sakura 85% WP); 100 g.ha-1, pre-emergence flumioxazine (Shato 50% WP); 100 g.ha-1, pre emergence metribuzine (Sencor 70% WP); 200 g.ha-1, pre-emergence of sulfentrazone (100 g.ha-1)+metribiozin (200 g.ha-1), pre-emergence of sulfentrazone (100 g.ha-1)+pyroxasulfone (100 g.ha-1), preemergence of sulfentrazone (100 g.ha-1)+flumioxazine (100 g.ha-1) and hand weeding. The results showed that application of sulfentrazone+pyroxasulfone at flowering stage of chickpea reduced 95% and 94% weed biomass and density, respectively and sulfentrazone+flumioxazin reduced 93% and 82% of weed biomass and density, were the most effective treatments. The highest increase in chickpea seed yield (67% and 60%, respectively) after hand weeding was achieved by these treatments. The pre-emergence treatment of sulfentrazone 300 g.ha-1 had the least positive effect (10%) on the increasing of chickpea seed yield. The results related to the effect of herbicide residues on the wheat yield in rotation showed that wheat grain yield as a result of applying preplant sulfentrazone (200 g.ha-1) was reduced by 32% compared to the control (untreated). The residues of pre-emergence sulfentrazone (300 g.ha-1) also had the most negative effect on both plant height and wheat grain yield  by 8.2% and 32.7% reduction, respectively. In conclusion, results of this experiment showed that, sulfonetrazone (Spartan)+flumioxazin (Shato) and sulfonetrazone (Spartan)+pyroxasulfone (Sakura) herbicides can be suggested for weed control in rainfed chickpea, because of their high efficiency in weed control and improving chickpea seed yield and minor negative residues effect on bread wheat performance in in crop rotation.