中文摘要：

为了明确河北低平原区覆膜植棉农田土壤温度分布特征,采用小区试验,研究了微咸水（5 g/L）灌溉条件下覆膜棉田不同土层深度和不同点位土壤温度的变化特征,并估算了裸露行和覆膜行的地表温度。结果表明,棉花生育期间不同深度处土壤温度都呈现了先增大后减小的趋势;随着土层深度的增加,土壤温度的变化趋于平缓,棉花生育期内0、10、20、40、60、100 cm深度处日均土壤温度的变异系数分别为24.13%、19.79%、18.25%、15.20%、13.10%、11.65%。覆膜具有增温作用,增温效果随棉花生育进程推进和土层深度增加而有所减弱;覆膜行和裸露行距离植株远处的土壤温度均大于其近处。采用能量平衡原理可以较好地估算地表温度,裸露行和覆膜行估算结果的符合指数（d）分别为0.986 9和0.985 5,Nash-Sutcliffe系数（NSE）分别为0.947 7和0.941 0。研究结果可为丰富棉花栽培技术体系提供理论支撑。

英文摘要：

To investigate soil temperature distribution in cotton fields with plastic film mulching in Hebei Lowland Plain, soil temperature dynamics in different positions were studied in a cotton field with plastic mulching and irrigation with brackish water （5 g/L）. The soil surface temperatures with and without film mulching in the row were simulated as well. Results showed that soil temperature at different soil depths increased first and then decreased during cotton growing season. Soil temperatures gradually became smooth with the increment of soil depth. In the whole cotton growing season, the variation coefficients of average daily temperatures at the depths of 0, 10, 20, 40, 60, and 100 cm were 24.13%, 19.79%, 18.25%, 15.20%, 13.10%, and 11.65%, respectively. Plastic film mulch could increase soil temperature. Mulching effect gradually weakened with the growth of cotton and the increase of soil depth. Either in the row with or without film mulching, soil temperatures at the positions far from cotton plants were higher than those near cotton plants. Soil surface temperature could be estimated accurately with the model based on energy balance. For soil sur- face temperatures in rows with and without film mulching, the indexes of coincidence （d） between estimation and observed values were 0.9869 and 0.9855, while the Nash-Sutcliffecoefficient （NSE） were 0.9477 and 0.9410, respectively. The study will provide an important theoretical support for developing cotton culture.