免耕对黑土春夏季节温度和水分的影响

通过田间定位试验,研究免耕与常规耕作对东北黑土区玉米和大豆生长早期土壤温度和水分的影响。研究结果表明:播种前,由于免耕与常规耕作(秋翻)覆盖率和含水量不同,免耕处理的玉米和大豆小区土壤的白天5cm地温均低于常规耕作处理,夜间差异不大;相同深度的玉米和大豆秋翻处理土壤日平均温度分别比免耕高0. 7℃和0. 5℃;随土壤深度的增加,土壤温度的差异逐渐减小。播种后,除了下午免耕5cm地温略低于秋翻外,下午至夜间免耕的10cm和15cm地温,均略高于秋翻的土壤温度。这是由于免耕下土壤水分增高引起的土壤热容量加大,从而缓解夜间降温和寒流影响,减缓土壤温度下降的结果。播种前,免耕处理的玉米和大豆地土壤水分分别比秋翻处理高2. 4%和1. 8%。播种后的一个月期间,免耕大豆土壤含水量比秋翻高2. 3%。初步的研究结果表明,免耕可以在一定程度上缓解春季黑土墒情不好的问题,这对保证出苗和幼苗的健康生长非常重要。

Effects of No-tillage Practices on Temperature and Moisture of a Black Soil in the Spring and Early Summer

Effects of no-tillage and convention tillage practices on soil temperature and moisture of a black soil in Northeast China during the early growing season of maize and soybean were reported in this paper. The results showed that there was great difference between no-tillage and fall ploughing treatments in the residues-covering rate and water content under both corn and soybean production before sowing. The daily average of surface temperature (5 cm) was 0.7℃ and 0.5℃ higher in the fall ploughing plots under maize or soybean production than those in no-tillage plots, and the difference declined with increase in depth. After sowing, except for a little low temperature in a depth of 5 cm occurred in no-tillage plots in the afternoon, the sub-surface temperatures of 10 cm and 15cm of no-tillage soils were greater than those in the fall ploughing plots from afternoon till late night. The content of soil moisture was 2.4% and 1.8% higher in no-tillage maize and soybean plots than those in fall ploughing plots before sowing. After sowing soybean, the soil moisture was 2.3% higher in no-tillage than in fall ploughing plots. This preliminary study demonstrated that no-tillage could improve soil moisture condition during the Spring in Black soil region of Northeast China, which was valuable for good emergence of young plants and their early growth.