北疆滴灌复种大豆田土壤温度分布特征

针对复种作物生长季节的特殊性,研究复种大豆田土壤温度在0~100cm深度土壤剖面的分布、日变化,生育阶段的动态及灌水对土壤温度的影响。结果表明,土壤温度受大气温度昼夜变化影响的土层临界深度为40cm,0~40cm土壤温度以24h为周期呈准正弦曲线波动,其振动变化幅度随土壤深度增加趋于平缓;土壤温度日变化呈上升和下降2个变化阶段,升温速率明显大于降温速率;适宜的灌水定额具有提高土壤温度的效果,360mm灌溉定额处理土壤温度最高,小灌溉定额和大灌溉定额均不利于提高土壤温度;土壤温度在大豆生殖生长阶段内宽行温度始终高于窄行但温差随生育期推移趋于一致,且土壤温度随时间推移呈逐渐下降趋势。

Distibution Characteristics of Soil Temperature in Drip-irrigating and Sequential Cropping Soybean Field in Xinjiang

According to the particularity of sequential cropping season, longitudinal distribution, daily variation, and seasonal dynamics of soil temperature in 0-100 cm depth were measured in the sequential cropping soybean fields, and the influence of irrigation on soil temperature was evaluated. The results showed that the soil critical depth is 40 cm where soil temperature is affected by diurnal variation of atmospheric temperature. The change of 0-40 cm soil temperature is quasi sinusoidal wave through a 24 h cycle, and its amplitude is shrinking with the increase of soil depth. Daily variation of soil temperaturehas has a rising phase and a falling phase, and the rising rate of soil temperature is greater than the decline rate. Appropriate irrigation quota is helpful to increase soil temperature, and the highest soil temperature is detected under 360 mm irrigation quota. More or less irrigation quota can not help to improve the soil temperature. Wide row soil temperature is always higher than the narrow row temperature at soybean reproductive stages, but soil temperature differences disappear along with the growth period. At the same time the soil temperature gradually decreases over time.