Water Evaporation Reduction Using Sunlight Splitting Technology

The imbalance between precipitation and water evaporation has caused crop yield reduction, drought, and desertification. Furthermore, most parts of the world are short of water, including China. We proposed a low-cost polymer multilayer film to reduce water evaporation by only passing through several sunlight wavelengths necessary for photosynthesis. A series of experiments were conducted to characterize the influence of partial sunlight on the reduction of water evaporation. Evaporation containers and evaporation pans were placed in open-air (CK), under a glass shed (GS), and under a glass-shed covered with multilayer films (GMF). Our results showed a significant reduction in water evaporation under GMF. Cumulative soil surface evaporation of CK, GS and GMF over 45 days was 80.53 mm, 68.12 mm, and 56.79 mm, respectively. Under GMF, cumulative water evaporation from soil and pan surfaces decreased by 29% and 26%. The slope (β1≠0) of simple linear regression showed a significant relationship between evaporation time and cumulative water evaporation (p = 0.000 < α = 0.05 shown in the ANOVA table). The correlation coefficient was more than 0.91 in all treatments, suggesting a strong positive linear relationship. This study may contribute to future drought resistance and agrivoltaic sustainability development.