Enhancing food production in hot climates through radiative cooling mulch: A nexus approach

With a booming population, global food demand is increasing rapidly. Various methods have been proposed to alleviate heat stress and improve yields for agriculture in hot climates. However, the damage caused by high root temperatures cannot be avoided due to a lack of efficient regulation strategies. In this work, we investigate a new soil-cooling strategy based on the daytime radiative cooling film. This film has a high emissivity across the atmospheric window, along with a high reflectivity in the solar spectrum. With a soil temperature drop of 12.5°C, the germination rate of cherry radish is improved from 39.6% to 81.3% after using this mulch. In a field test during a hot summer, this mulch increased the fresh weight yield of Chinese cabbage by 127.4%, which was attributed to reduced root heat stress. Moreover, the applicability of this radiative cooling mulch in diverse geographical and climatic conditions was discussed based on a global-scale simulation. The limitations of this radiative cooling mulch and future development perspectives were discussed here. This passive cooling strategy paves a new way to tackle the water-food crisis without extra energy consumption.