Journal of Crop Production and Processing

To study the effects of vegetable oils on the performance of Imazethapyr (a herbicide with a relatively high amount of residue in the soil and environment) in barnyardgrass (Echinochloa crus-galli Beauv) control, a factorial experiment based on completely randomized design with four replications was conducted in the Research Greenhouse of College of Agriculture, Birjand University, Birjand, Iran in 2016. The treatments consisted of Imazethapyr concentration at six levels (0, 6.25, 12.5, 25, 50, and 100 g ai ha^-1) and adjuvant at 6 levels (with and without Coconut, Peanut, Turnip, Bitter almond and Castor oils). The results of this study revealed that the concentration of herbicide, the type of adjuvants and the interaction between concentration and adjuvants were significant on all measured traits including height, fresh and dry weight of the shoot and root, root volume and root length. Castor oil and coconut oil showed the highest and lowest potential in improving the efficacy of Imazethapyr. In the presence of vegetable oils, the ED₅₀ values required for the traits of shoot and root fresh weight were decreased significantly compared to the dry weight of the shoot and root. Relative potency values showed that using any of the vegetable oils could reduce the amount of herbicide needed to control the E. crus-galli. Due to the lessened reduction in measured traits in the presence of vegetable oil treatments, using these additives has the potency to reduce the entry of Imazethapyr herbicide to the environment.

In order to evaluate the potential of citogate and turnip vegetable oil in increasing the performance of barnyardgrass (Echinochloa crus-galli) control by colthodim and haloxyfop-r-methyl ester herbicides, two greenhouse experiments were carried out in the Research Greenhouse of the Faculty of Agriculture, Birjand, Iran, in 2016; this study was based on a factorial arrangement as a completely randomized design with three replications. Treatments in each experiment included herbicide concentrations at seven levels (0, 6.25, 12.5, 25, 50, 75, and 100% of the recommended dose) and additives were applied at three levels (turnip oil, citogate, and without additives). The application of additives with colthodim herbicide on barnyardgrass (based on the shoot dry weight) led to 4.5% and 5.4% decreases in ED₅₀ in the presence of turnip oil and citogate, respectively. Based on the root dry weight, ED₅₀ was reduced to 22.9% and 21.6% in the presence of turnip oil and citogate, respectively. The results of the use of additives with Haloxyfop-r-methyl ester also showed a similar trend. However, the increase in the efficiency of Haloxyfop-r-methyl ester was higher than that of colthodim herbicide. The Haloxyfop-r-methyl ester ED₅₀ values for the shoot dry weight of barnyardgrass were reduced by 14% and 16.3% in the presence of turnip oil and citogate, respectively. The Haloxyfop-r-methyl ester ED₅₀ values for the root dry weight in the presence of turnip oil and citogate were 10 and 7 times higher than those in the treatments without additives, respectively. According to the results of this study, application of appropriate additives may lead to decrease in the extent of herbicide contamination of soil and water resources.