Ultrasonic waves can have an effect on some of the physiological traits of cowpea when trifluralin is added to the soil

An experiment was conducted at the Faculty of Agriculture, Shahrood University, as a randomized complete block design with four replications to investigate the effect of ultrasonic waves and seed priming on some quality traits of cowpea under soil application of trifluralin. Nine treatments were: T1: control, T2: ultrasonic waves, T3: ultrasonic waves + reduced herbicide dose (1 L ha-1), T4: ultrasonic waves + recommended herbicide dose (2 L ha-1), T5: hydro-priming, T6: hydro-priming + reduced herbicide dose, T7: hydro-priming + recommended herbicide dose, T8: reduced herbicide dose, T9: recommended herbicide dose. The results showed that the effect of treatments was significant on all traits except leaf phosphorus. The maximum chlorophyll a (1.30 mg g-1 FW), carotenoid (1.82 mg g-1 FW), leaf relative water content (79.9 %), and leaf nitrogen (3.97%) were obtained in ultrasonic treatment, which resulted in a significant increase of 28.7, 22.1, 7.9, and 18.5 percent, respectively, in comparison to the control. In comparison to the ultrasonic treatment, ultrasonic waves + recommended herbicide dose reduced chlorophyll b, RWC, and leaf nitrogen by 29.3, 21.1, and 35.3 percent, respectively. In comparison to herbicide application alone, the combination of ultrasonic waves and the recommended herbicide dose reduced chlorophyll a and total chlorophyll by 29.7 and 22.2 percent, respectively. Overall, the results of the present study showed that pretreating cowpea seeds with ultrasonic waves could increase photosynthesis pigments, relative water content, and leaf N (in the absence of herbicide use).