Abstract: Based on the soil temperature and humidity data of soybean farmland under conservation tillage in Northeast China in the published article, the impact of conservation tillage measures on the soil hydrothermal status of soybean farmland in Northeast China was quantitatively assessed by using conventional tillage (CT) as a control, no-tillage (NT), reduced tillage (RT), straw mulching (SM), and no-till straw mulching (NTSM) as treatments. The results showed: compared with CT, conservation tillage increased the soil volume water content of 0-170cm soil layer in soybean farmland in Northeast China by 9.2%, and reduced the temperature of the shallow soil layer (0-30cm) by 8.2%. Four conservation tillage could increase soil moisture under different climatic conditions; straw mulching could increase soil moisture content throughout the growth period of soybeans, and the effect on soil hydrothermal was greatest during the nutrition period of soybean, and soil temperature increased with the increase of straw mulching; the magnitude of soil temperature reduction by conservation tillage decreases with the decrease of soil clay particles, the magnitude of soil moisture increased by conservation tillage decreases with the increase of soil depth. Among them, NTSM at different soil depths was the most obvious effect of water storage and moisture retention, and the soil moisture in the soil layer of 0-20cm was increased by 32.9%. In summary, conservation tillage could increase soil moisture but reduce soil temperatures. Temperature, precipitation, growth period, straw mulching amount, soil type and soil depth all had an impact on soil hydro-thermality in soybean farmland under conservation tillage.

Key words: Northeast China, Soybean, Conservation tillage, Soil hydrothermal, Meta-analysis