Photocontrol of Weed and Application Reduced Dosage of Imazethapyr and Trifuralin on Weed Management of Chickpea

Weed cause enormous loss of chickpea yield and its quality. Photocontrol of weeds (soil cultivation in darkness) is a preventive weed control method, the basic aim of which is to reduce the germination of light sensitive weed seeds by excluding light during soil disturbance, in order to reduce the emergence of weeds in the crop. Considerable research has examined the potential use of lower-than-labeled herbicide doses. There are reasons for the potential successful use of reduced herbicide doses: (i) registered doses are set to ensure adequate control over a wide spectrum of weed species, weed densities, growth stages, and environmental conditions; (ii) maximum weed control is not always necessary for optimal crop yields; and (iii) combining reduced doses of herbicides with other management practices, such as tillage or competitive crops, can markedly increase the odds of successful weed control. This study was conducted to evaluate the photocontrol of weeds and application of reduced dosage of Imazethapyr and trifluralin herbicides on weed control and yield of chickpea.
The experiment was designed as a strip plot based on a complete randomized block with three replications. The experiment had 3 factors: main plot consisted of tillage method at 3 levels (night tillage, day tillage, light-proof cover tillage), subplot consisted of Trifuralin (480, 960 and 1440 grams of active ingredient per hectare) Imazethapyr (50, 100 and 150 grams of active ingredient per hectare), weed infestation and weed free were considered as control. During the growing season, six sampling steps (28 days after planting (410 Growth Degree Day (GDD)), (45 days after planting (715 GDD)), (57 days after planting (975 GDD)), (70 days after planting (1280 GDD), (75 days after planting (1620 GDD)), (90 days after planting (2025 GGD)) were carried out. For statistical analysis the data normality of the distribution were analyzed with Sigma plot software, and if necessary, the data transforming and then ANOVA was performed using MSTATC. The means were compared using Duncan's multiple range test and graphs were drawn using Excel and Sigma plot software.
Result and In the growing season, the application of herbicide had significant effect (P≤ 0.05) on weed density. In all stages of sampling, weed density was higher in light-proof cover tillage treatments than day and night tillage operations. According to the results based on the type of tillage, night tillage and light-proof cover tillage treatments did not reduce weed density compared to day tillage. In the reduced Imazethapyr application, there was significant difference at 1620 GDD with others, but this amount of application did not effectively control weeds. In treatment of 1280 GDD, the amount of reduced application of Trifuralin was significantly different with other amounts but could not control weeds. However, there was no significant difference between the amounts of Trifuralin from this stage until the end of the growth season. By examining the biomass of chickpea during the growing season in the applied amounts of herbicides, it was determined that the growth of all treatments was the same order of 1200 GDD. From this stage, the difference between treatments increased until the end of the growing season, in the end of the growing season, control of weed control was the highest and control without chickpea was the least biomass. The effect of herbicide application dosage on the density of the weeds was significant (P≤ 0.05). Chickpea grain yield in light -proof cover tillage was 45 percentage lower than night-time tillage and day time tillage treatment and there were no significant differences between night-time tillage and day-time tillage treatment. The lowest and the highest yield was respectively in weed infestation (1151 Kg/ha) and weed control (1977 Kg/ha) and yield in the dosage of herbicides. Did not differ significantly. The results of this experiment show that reduced dosage of herbicides can control weed without negative effects on chickpea yield.
The results showed that weed density and weed biomass was more than in light-proof cover tillage treatment compared to night and day tillage and there were no significant differences (P≤ 0.05) between night and day tillage. Weed biomass showed no significant differences between herbicide treatments. The reduced dosage of herbicide in Imazethapyr treatment did not have enough control but there were no significant differences between herbicide treatments. Chickpea yield had no significant difference (P≤ 0.05) between reduced, recommended and increased dosage herbicides