A review of impacts of hydrogels on soil water conservation in dryland agriculture

Abstract

Soil water conservation is a crucial aspect of dryland crop cultivation for mitigating the excessive heat and water stress induced by climate change. The application of acrylamide-based hydrogels is an effective soil management practice for enhancing water retention, controlling soil erosion, and improving soil health in water-limited regions. Hydrogels promote water conservation in soils, which increases water availability to plants and reduces the total irrigation demands. However, the systemic knowledge gaps of the effectiveness and application method of hydrogel materials and their quantified effects on degradability, drought resistance, irrigation system, and soil water conservation in arid and semi-arid environments have not been investigated extensively. Therefore, this review examines the impacts of hydrogels on soil water conservation, with a focus on their mechanisms, applications, and potential benefits in arid and semi-arid regions. The effects of hydrogels are compared with those of other soil water conservation techniques, such as mulching, biochar and compost, and their respective strengths and applicability in dryland regions are highlighted. The result of study indicates that hydrogels enhance water infiltration in soil, reduce surface runoff, and increase soil physio-chemical properties by improving the soil structure and aggregate stability. Hydrogels also reduce evaporation losses by 20–30 % by maintaining high soil moisture contents, which are crucial for healthy crop growth in water-limited areas. Furthermore, hydrogels minimize soil erosion, particularly in furrow and sprinkler irrigation systems. Despite their several benefits, the use of hydrogels in dryland agriculture poses challenges, such as environmental persistence, toxicity of acrylamide residues, and cost-effectiveness for small-scale farmers. Future research should address the potential environmental concerns associated with hydrogel use, including considerations of risk of degradation and toxicity to plant in different regions. Finally, the use of hydrogels based on a promising method for improving soil water retention in dryland agriculture is recommended.