The global population is projected to reach 9.6 billion people by 2025, requiring food production to increase by 70% to meet the demand of the huge population. Water is most limiting natural resource for agricultural production due to the freshwater shortage and enormous need for irrigation. Dry cropland accounts for 84% of the cultivated area in the arable land, which, without irrigation, can lead to great loss of crop production. Global climate change and anthropogenic contamination further aggravate this threat.
Current freshwater production can barely meet the urgent demand for agricultural production, especially for drought regions facing severe water scarcity. Moreover, current water irrigation relying on complex water supply chains is inconvenient and expensive.
These challenges motivate the exploration of a new water resource- atmospheric water, which is abundant and can be utilized regardless of geographical and hydrologic conditions. The recent development of atmospheric water harvesting, which enables water capturing from the air, provides the promise for distributed irrigation system powered by solar energy, supplying water without centralized water and power supplies.
Low water utilization efficiency and low relative humidity (RH) near the soils due to the poor water holding capacity of current soil is another issue. The severe water loss from runoff and evaporation leads to tremendous consumption of freshwater and affects the critical phases in plant growth including seed germination and establishment. Efficient use of water resources is significant and necessary for agricultural production.
Superabsorbent gels with excellent water retention behaviors have been studied as water management materials for agricultural and horticultural applications in the past few years, promising to increase the survival rate and alleviate the drought stress effects on the plants in arid regions.
Researchers at The University of Texas at Austin have invented the super moisture absorbent gel (SMAG) modified soil to achieve atmospheric water irrigation for agricultural production. The SMAG-soil, composed of mixed micro-particles of SMAG and soil, can capture moisture from air and store water in the gels during the night with relatively high RH and low temperature. During the daytime, liquid water without ionic solutes can be released for irrigation powered by solar radiation.
Moreover, the RH in the irrigation system can be maintained high and stable, due to the improved water holding capability of the SMAG-soil. Therefore, the SMAG-soil enables atmospheric water irrigation for crop production in remote and drought regions without liquid water resources.
- Atmospheric water irrigation based on super moisture absorbent gels modified soil provides for sustainable agricultural production with low cost and high efficiency.
- The atmospheric water irrigation described in this invention can utilize the moisture in the atmosphere as the new freshwater resource for irrigation, overcoming the environmental and regional dependence.
- The SMAG-soil in the system enables passive liquid water releasing free of ionic solutes powered by solar radiation without extra energy input.
- The system can maintain a high and stable RH due to the improved water holding capacity of the SMAG-soil, favoring seed germination and plant growth.
- The SMAG-soil could serve as a water and nutrient management system for collection, storage, and controllable release.
- The process is scalable, sustainable, highly efficient, and cost-effective.
Active PCT application serial number US2021/053341, filed October 4, 2021.