Effect of superabsorbent hydrogel Aquasorb application on mitigating drought stress, grain yield and water use efficiency of mung bean (Vigna radiate L.)

Water is an important economic resource in many parts of the world, especially in arid and semi-arid reigns. Increasing in irrigation intervals and making use of superabsorbent are two basic strategies for saving and efficient use of irrigation water. To investigate the effect of superabsorbent polymer Aquasorb on mitigating drought stress, growth characteristics, grain yield and water use efficiency of mung bean (Vigna radiate L.), a field experiment was conducted at two regions (Khorramabad and Kuhdasht) using split-plot arrangement in randomized complete block design with four replications. The treatments included irrigation interval at three levels (5, 10, and 15 days) as main plots and four levels of superabsorbent polymer Aquasorb (zero; control, 100, 200 and 300 kg.ha-1) as subplots. Results, averaged across irrigation interval and locations, showed that the highest grain yields (1918 kg.ha-1) was observed at 200 kg superabsorbent.ha-1 and the lowest grain yield (1232 kg.ha-1) was obtained in control. Also, the highest biomass (8530 kg.ha-1) and water use efficiency (1.12 kg grain yield.m-3) belonged to 200 kg superabsorbent.ha-1. The highest proline content (0.56 mg.g-1 DW) was recorded in 15-days irrigation interval and control. Also the lowest protein content (0.17 mg.g-1 DW) was obtained in 5-days irrigation interval and control. Generally, results revealed that application of Aqasorb superabsorbent hydrogel up to optimum level (200 kg.ha-1) can improve the growth and agronomic characteristics of mung bean and can reduce the impact of drought. Application of higher levels not only will increase the cost of production but also will reduce water use efficiency and other agronomic characteristics of mung bean.