Optimizing straw mulching to improve soil water,temperature,nitrogen availability and crop yield in rain-fed maize-soybean intercropping system

SONG Chenghao; GAO Xiaoyu; XU Bing; TIAN Delong; WANG Guoshuai; LI Zhishuang; BIAN Danciwang

doi:10.13522/j.cnki.ggps.2025350

Abstract：[Objective]Straw mulching is widely recognized as an effective practice for conserving soil water and regulating temperature,but its optimal practical application remains unclear.This paper aimed to determine the optimal straw mulching strategy for maize-soybean intercropping system in the rain-fed region of eastern Inner Mongolia.[Method]The experiment was conducted in a field with four straw mulching treatments.During the experiment,we measured soil evaporation,soil water content and temperature,bioavailable nitrogen,as well as the yields of maize and soybean in each treatment.[Result]The optimal straw mulching treatment was the application of 10 000 kg/hm2 of straw cut into 10-20 cm segments 15 days after seedling emergence.During the entire growth period of the two crops,this treatment reduced average daily soil evaporation by 30％and increased the average soil water content in the 0-100 cm soil layer by 12％.It provided a dual regulatory effect on soil temperature,maintaining higher temperatures during the early seedling-jointing stage and reducing temperatures during the later filling-maturity stage.This effectively alleviated early-stage frost stress and late-stage heat stress.In addition,it significantly increased soil alkali-hydrolyzable nitrogen,enhanced rainwater use efficiency by 6.99％,and increased maize and soybean yields by 7.3％and 6.5％,respectively,compared with the control without straw mulching.[Conclusion]For maize-soybean intercropping systems in the rain-fed region of eastern Inner Mongolia,the optimal straw mulching practice is apply 10 000 kg/hm2 of straw cut into 10-20 cm segments 15 days after seedling emergence.These results provide a scientific basis for optimizing evaporation reduction and water conservation in rain-fed cropping systems in the study region.