Effect of superabsorbent polymers on moisture retention of two contrasting soils at different suctions

Document Type : Research

Authors

1 Master's degree student, Department of Water Engineering, Islamic Azad University, Kerman branch

2 Assistant Professor, Department of Water Engineering, Islamic Azad University, Kerman branch

Abstract

One of the strategies to combat water resources deficiency and drought crisis, especially in arid and semiarid region is superabsorbents application. This study investigates the influence of some polymers on moisture behavior of two different soils. For this purpose, the experiments were carried out as factorial based on complete randomized design, with three replications. The treatments were included of two types of polymer (Tarawat and Stockosorb), each in five levels (0, 2, 4, 6 and 8 g/kg soil), and two soil textures (loamy sand and sandy loam). After treatment preparation, soil moisture content was measured at 7 suctions of 0, 0.3, 0.5, 1, 5, 10 and 15 bars. The results showed that for all suctions, the type of polymer, level and soil texture had significant influence (P<0.01) on moisture retention. Application of polymers in the loamy sand soil led to higher moisture content than the sandy loam soil. Also for all suctions, increasing polymer level, moisture retention enhanced compared with the control. In addition, the highest increase was observed at suctions between 0.3 to 0.5 bar. For the loamy sand soil, the largest level of Tarawat and Stockosorb compared with the control, resulted in increases of moisture content between 182.4-197.7 and 156.4-166.1 %, respectively, whereas these values for the sandy loam soil were 47.84-54.71 and 36.24-37.82 %, respectively. This finding indicates higher efficiency of Tarawat compared to Stockosorb, particularly for the loamy sand soil. The results also implied that increasing the level of polymer, the percentage of pores in the range of 60 to 100 micron enhanced than other pore sizes

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