Sustainable Agricultural Water Supply: Atmospheric Water Harvesting with Degradable and Biosafe Hydrogel

Seventy percent of global freshwater resources are consumed by agriculture, leading to severe water shortages due to the increasing demand for water in irrigated agriculture, which in turn poses a significant threat to food security. To address this challenge, innovative solutions are needed to optimize water use in agriculture. In this study, sodium lignosulfonate/chitosan/calcium chloride amphiphilic collection hydrogel (CSL-CaCl 2 ) is prepared. This hydrogel captures water from the atmosphere for soil water harvesting, thereby reducing the requirement for irrigation water. The hydrogel captures moisture from the air through its salt and porous structures, transferring it to a polymer network for storage. When exposed to daylight, the water-absorbed hydrogel is able to quickly release water into the soil, increasing the soil water content. The amount of water released from the hydrogel is 0.81 kg∙m −2 , equivalent to increasing the average annual precipitation in the temperate monsoon climate zone ( i.e. , Tianjin, China) by 51 %, which could effectively reduce the demand for agricultural irrigation water. The hydrogel not only promotes plant growth, but also has excellent water retention, improved soil physicochemical properties and exhibits excellent degradability. This work provides important insights for alleviating water shortages in irrigated agriculture.