Effects of deficit irrigation (RDI) and partial root-zone drying (PRD) on water productivity and photosynthetic characteristics of mungbean (Vigna radiate L.)

In order to study the effect of deficit irrigation (DI) and partial Root-Zone Drying (PRD) on water productivity and photosynthetic characteristics of mungbean, a field experiment was conducted as a split-plot experiment in a randomized complete block design with three replications and nine treatments at the research farm, Ilam University during the growing season in 2021. Treatments included three levels of deficit irrigation (50, 70 and 100% of water requirement) as main plots and three irrigation methods including; usual irrigation, fixed partial root-zone drying, and alternative partial root-zone drying as subplots. The results showed that the effect of drought stress on water productivity, carboxylation efficiency, and photosynthetic water use efficiency was significant. Also, the Interactive effect of drought stress and irrigation method on water productivity and carboxylation efficiency was significant. The highest amount of water productivity, in all irrigation methods, was found in 75% water requirement treatment. The highest water productivity (0.49 kg/m3) was recorded with the alternative PRD method in 75 % of the water requirement level. There was no significant difference between alternative PRD and DI methods at 75 and 100 % of water requirement levels on water productivity. In severe drought stress, water productivity in the alternative PRD method was significantly higher than the other two methods. Therefore, in drought stress conditions, using the PRD method was effective in reducing the effects of drought stress.