Abstract: In response to challenges such as low rainfall, low water use efficiency, and pollution from traditional plastic mulch in Inner Mongolia, a field experiment was conducted in 2023 at the Inner Mongolia Autonomous Region Academy of Agriculture and Animal Husbandry Sciences. There were four treatments: black polyethylene mulch (PE), white biodegradable water-permeable mulch (S1), gray biodegradable water-permeable mulch (S2), and no mulch (CK). We investigated the degradation performance of different types of mulch and their effects on soil moisture, temperature, and water use efficiency of sugar beets. The results showed that the white biodegradable mulch had the fastest degradation rate. Compared to the no-mulch treatment, all three types of mulch improved soil hydrothermal environment, with the best performance of the white biodegradable mulch. Under white biodegradable mulch coverage, soil moisture significantly increased by 6.95% to 18.86%, and soil temperature significantly rose by 2.5 to 5.5 ℃. Water consumption, water consumption intensity, and water consumption modulus coefficient significantly decreased by 10.15%, 28.67%, and 12.94%, respectively. Water use efficiency significantly improved by 14.89%, while soil bulk density significantly decreased by 3.05%, and soil porosity significantly increased by 6.14%. Net photosynthetic rate, intercellular CO₂ concentration, transpiration rate, and stomatal conductance of sugar beets significantly increased by 18.27% to 30.42%, 13.55% to 21.29%, 22.28% to 59.85%, and 17.94% to 76.26%, respectively. In conclusion, white biodegradable mulch coverage effectively regulates soil hydrothermal environment, improves water use efficiency during the growth period, and promotes sugar beet growth.

Key words: sugar beet, biodegradable mulching film, soil moisture, soil temperature, water utilization