The Effect of Superabsorbent Polymers on the Water Holding Capacity and Water Potential of Karkhe Noor Sandy Soils

Superabsorbent polymers are used in agriculture for the purpose of increasing water use efficiency in arid and semi-arid regions. In this research two kinds of superabsorbent polymers, Super AB A200 and Herbosorb were used on sandy soils of Karkhe Noor river bank near Hamidieh. The effect of 5 concentration levels of 0.3, 0.6, 0.8, 2 and 4 grams per kilogram of soil in 3 replications was studied on the parameters of soil moisture characteristic curve using RETC program and Rosetta database. It was observed that fitting of the data to the RETC model was better compared to Rosetta. Statistical analysis of the research results show that for sandy soils in these experiments there was a significant difference at one percent level for all the polymers used and the control treatment at suctions of 0.3, 1, 3, 5 and 15 bars. On the other hand for the different concentration levels of 4, 2, 0.8, 0.6 and 0.3 g/kg soil, volumetric soil moisture content showed a significant difference at one percent level. Among the superabsorbents used A200 with application rate of 4 g/kg soil resulted in the highest effect. Soil available water for plant use showed an increase compared to the control treatment. It was finally concluded that the application of 4 gram Super AB A200 and Herbosorb per kilogram soil increased soil available water about 350 and 320 percent respectively.