Abstract: Taking soybean cultivar Jindou 23 as test object, a field experiment was conducted at the Zhenyuan experimental station of Gansu Academy of Agricultural Sciences to study the effects of various plastic mulching treatments on the soil moisture and temperature and soybean grain yield on a semiarid dryland of Northwest China. Four treatments were installed, i.e., plastic film mulching with double ridges and furrow planting (FMRFC), plastic film mulching without ridges and with furrow planting (FMFC), plastic film mulching with strip planting (FMSC), and no mulch strip planting (NMSC, CK). During the drought year (the precipitation in soybean growth period was 246.3 mm) and wet year (407 mm), the daily soil temperature in 0-20 cm layer in all mulching treatments varied in “S” shape, and its fluctuation became smaller with soybean growth. The mulching treatments raised the daily average soil temperature in 0-20 cm layer by an average of 0.5-2.5 ℃ from the seedling (VE-V3) to seed filling (R6) stage, with the average soil temperature in whole growth period raised by 1.3-1.6 ℃. Both in dry year and in wet year, mulching treatments promoted the soil moisture consumption in 0-120 cm layer by soybean, but increased the average soil moisture content and water storage in 0-200 cm layer by 1.2%-1.4% and 62.7-70.3 mm, respectively. As compared to CK, treatments FMRFC and FMFC had significant effects in improving the soil temperature and moisture environment in dry year, and greatly improved the yield
related traits such as plant height, branching number, pods per plant, and 100-seed mass. FMRFC increased the yield by 27.7%-51.1% and raised the water use efficiency (WUE) by 47.7%-56.3%, whereas FMFC increased the yield by 10.2%-25.2% and raised the WUE by 33.3%-35.4%, as compared to CK. It was suggested that FMRFC and FMFC could be the most efficient planting systems for the soybean production in the dryland farming of Northwest China.