International Journal of Environment and Climate Change

Water scarcity, declining soil quality and increasing weed pressure pose significant challenges to sustainable crop production, particularly in arid and semi-arid regions. This review synthesizes current knowledge on the agronomic role of hydrogels (superabsorbent polymers, SAPs) in improving soil properties, crop growth, nutrient dynamics, water-use efficiency, and crop–weed interactions. Hydrogels are classified into synthetic, natural, and semi-synthetic types, each differing in swelling capacity, ion sensitivity, and biodegradability. Their physicochemical properties enable enhanced soil moisture retention, moderated soil temperature, improved porosity, and modified hydraulic conductivity, particularly in coarse-textured soils. These soil-level improvements translate into better seed germination, root architecture development, vegetative growth, photosynthetic stability, and reproductive performance under water-limited conditions. Hydrogels demonstrate strong synergy with deficit irrigation strategies, improving water productivity indices and mitigating drought stress by stabilizing rhizosphere moisture and nutrient availability. Furthermore, hydrogel incorporation influences nutrient retention and fertilizer use efficiency, particularly for nitrogen, phosphorus, and potassium, by reducing leaching losses and enabling controlled-release formulations. However, modifications in soil moisture dynamics may alter weed germination timing, species composition, and crop–weed competition. While improved crop vigour can enhance competitive advantage, the ecological consequences for weed communities remain context-dependent and require integration with sound weed management practices. Overall, hydrogels offer substantial potential as multifunctional soil amendments in climate-resilient agriculture, particularly in water-limited environments, but their agronomic efficiency depends on soil texture, application strategy, and integration with holistic crop and weed management systems.