عنوان مقاله [English]
Application of water-absorbent material to increase Water productivity (WP) has been considered by researchers in recent decades. In this regard, different materials with different nature in water absorption and storage have been introduced. Aquasource is a kind of water-absorbent polymers that intruduces as an additive for modification of soil-water-plant relationship. Therefore, the present study was conducted to investigate the effect of application of Aquasource superabsorbent on WP of soybean using experimental plots. This study was performed in a factorial experiment with a completely randomized design and three replications. The first factor was two different irrigation intervals (4 and 7 days) and the second factor was different levels of superabsorbent (zero, 200 and 300 kg/ha). During the growth period, the amount of soil moisture was measured using a hydrometer. At the end of the plant growth period, yield and yield components and WP were determined. The results showed that the effect of irrigation interval on all indices was significant. The interaction between Irrigation and superabsorbent on water use and yield was significant. By changing the irrigation interval from 4 to 7 days, the average irrigation water, yield, oil yield, protein yield, WP of oil and protein decreased by 30, 50, 52, 50, 26, 23 and 30 percent, respectively. Aquasource superabsorbent reduced the average water use by 10% compared to the control treatment. Under the application of two levels of 200 and 300 kg of superabsorbent per hectare, increasing the depth of irrigation water to more than 630 mm did not have much effect on crop yield. Use of superabsorbent also reduced the appropriate irrigation depth to achieve the highest WP from 700 to 630 mm. This study suggests that the use of superabsorbent at a rate of 200 kg/ha (probably the optimal limit) increase grain yield, WP of oil and protein.