Effects of Semi-Film and Full-Film Mulching on Soybean Growth, Biological Nitrogen Fixation and Grain Yield

Soybean film mulching has shown promise in maintaining consistent and high yields in semi-arid regions. However, the specific impacts of full-film and semi-film mulching on soybean growth, root nodule traits and grain yield are poorly understood. This 2-year study (2021–2022) investigates the effects of full-film and semi-film mulching on soil moisture, soybean growth and yield. Our findings revealed that semi-film mulching increased soybean yield by 18.12% compared to full-film mulching, averaged across 2 years. Furthermore, the semi-film treatment significantly enhanced biological nitrogen fixation ability, increasing root nodule numbers by 24.81%–33.43%, compared to full-film mulching. This improvement also positively affected soybean quality, with crude protein content increasing by 5.89% in 2021 and 4.14% in 2022 compared to full-filming. Moreover, semi-film mulching helped maintain soil moisture and temperature during later soybean growth stages. There findings suggest that semi-film mulching is a viable agricultural strategy for soybean cultivation in semi-arid regions, improving soybean quality and efficiency while promoting environmental sustainability.