Hydrogels in Agricultural Applications: Recent Advances, Challenges, and Future Prospects

Water scarcity, climate variability, poor soil water retention, and nutrient loss are major concerns in agriculture. Hydrogels have emerged as promising candidates in countering these issues owing to their ability to absorb, retain, and release large quantities of water through their three‐dimensional polymeric networks. These can withhold and release water, fertilizers, nutrients, and others and thus have the potential to improve water and nutrient management of soil. This review provides an overview of the fundamental principles governing the agricultural hydrogels, including their composition, physicochemical characteristics, swelling behavior, water retention and release mechanisms, gel fraction, biodegradability, soil–water relationships including matric potential, and the influence of environmental factors such as salinity and irrigation water quality on their performance. It also gives an outline of the classification of hydrogels and their advantages and limitations. This review further examines the diverse agricultural applications of these materials, such as soil conditioners, seed coatings, water retention agents, and carriers for fertilizers. Additionally, it analyzes the challenges that continue to limit their large‐scale application, including scarcity of data on long‐term field validation, incomplete understanding of soil and environmental factors, variability in degradation behavior under field conditions, and the need for crop‐ and soil‐specific hydrogel formulations. Moreover, this review highlights the need for future research on field‐scale validation, stimuli‐responsive materials, environmentally sustainable and biodegradable hydrogel systems, the use of renewable and agricultural waste‐derived feedstocks, and the practical and economic factors, including deficit irrigation and fertigation compatibility and the cost of adoption, that will determine real‐world implementation.