Polymeric Hydrogels in Agriculture: Environmental Performance, Sustainability Challenges, and Future Perspectives
Kaveh Rahimi Mamaghani, Marzieh Alikarami, Hossein Saremi
Abstract
Climate variability and freshwater scarcity increasingly constrain crop production, motivating soil amendments that improve water and nutrient use efficiency. Polymeric hydrogels, cross-linked, water-swelling networks, are emerging as adaptable materials for climate-smart agriculture. By retaining and gradually releasing water and agrochemicals, they buffer soil moisture, reduce irrigation frequency, and enhance fertilizer utilization. Recent advances move beyond simple superabsorbent behavior toward multifunctional systems for controlled nutrient delivery, seed coating, and microbial inoculation, and toward stimuli-responsive “smart” matrices that couple with precision irrigation and sensing. This review synthesizes hydrogel chemistry, cross-linking strategies, and structure–property relationships that govern swelling, mechanics, and release kinetics under soil-relevant ionic and pH conditions. We critically assess agronomic performance across crops and soil types, highlight opportunities with biodegradable biopolymer and hybrid designs, and examine sustainability dimensions (cost, durability, biodegradability, life-cycle impacts, and potential microplastic risks) relevant to environmental chemical engineering and policy. Looking forward, we outline design-for-degradation criteria, reporting standards for field trials, and integration pathways with digital agriculture to accelerate responsible deployment. Overall, adaptive hydrogel platforms show strong potential to deliver water and nutrients more efficiently while aligning with environmental safeguards necessary for scalable, climate-resilient food systems. This review is among the first to integrate structure–function mapping, mechanistic modes of action, and a biodegradability framework for agro-hydrogels. It highlights design and reporting practices that can accelerate safe and sustainable hydrogel adoption, aligning with global climate adaptation and food security goals.