Investigating the efficiency of composite hydrogels based on chitosan in absorbing and retaining moisture in soil

Considering the global challenges of water scarcity and the need to optimize water use in agriculture, the use of biodegradable hydrogels such as chitosan is a promising solution for increasing water productivity in soil. This study investigates the use of chitosan-based composite hydrogel in soil moisture absorption and retention. In order to investigate the effectiveness of chitosan-based composite hydrogel in soil water retention and moisture absorption, a completely randomized design with five treatments and three replications was conducted. The results showed that the average percentage of weight moisture in irrigation treatments with chitosan hydrogel placed on the surface and depth was about 2.2 and 4.2 percent higher than the irrigation treatment without hydrogel, respectively. Also, in treatments without irrigation, the weight moisture with hydrogel on the surface was 31.1 percent higher than the treatment without hydrogel at the end of the experiment. At the end of the experiment, the weight moisture content of the hydrogel treatment was 0.11, 1.86, and 1.96 percent higher than that of the non-hydrogel treatment in the first, second, and third replicates, respectively. The results showed that under non-irrigated conditions, the use of hydrogel on the soil surface increased air moisture absorption and soil moisture (under dryland conditions). Also, the use of hydrogel (especially in the soil depth) in irrigated treatments increased soil moisture retention, while in the non-hydrogel treatment, soil moisture decreased more rapidly.