宁夏不同种植年限下硒砂瓜土壤干燥化效应研究

Effects of Different Growth Years of Watermelon on Soil Desiccation in Gravel-Sand Mulched Field in Ningxia

通过对压砂地不同种植年限下土壤干燥化效应进行研究,为宁夏中部旱区压砂地可持续发展提供理论依据。在观测压砂3,8,12,16,25a的土壤含水量的基础上,分析比较不同种植年限下土壤含水量、水分过耗量、干燥化指数、干层厚度等土壤干燥化指标。结果表明:不同年限下0—600cm的土壤含水量、贮水量和有效贮水量的均值分别为11.24%,936.00mm和506.27mm;随种植年限的增加,0—600cm土层平均土壤含水量、贮水量呈递减趋势,水分过耗量逐渐增大;不同种植年限下土壤剖面含水量随土层深度的增加呈先减小后增大最后逐渐平稳的趋势;压砂地土壤干燥化系数为68.29%～162.36%,平均干层厚度为283.33cm,以中度和轻度干燥化强度为主;典型相关性分析发现,经纬度、种植年限、粉粒及砂粒含量等环境因子是影响土壤干燥化指数和土壤干层厚度的重要因素。

The study of soil desiccation in different growth years can provide the theory basis for improving the utilization on the gravel-sand mulched field in the arid zone of central Ningxia.Based on observation of soil moisture contents of fields with 3 years,8 years,12 years,16 years and 25 years of gravel-sand mulch in the arid zone of central Ningxia,soil moisture contents,soil water overuse rate,soil desiccation indexes and thickness of desiccated were calculated,analyzed and compared.The Results showed as follows.Mean soil moisture contents,water storage and available soil water storage were 11.24%,936.00 mm and 506.27 mm in the fields with the gravel-sand mulched under different years of growing watermelon.With the increase of growing years,soil moisture contents,water storage decreased gradually,soil water overuse rate increased gradually in the 0-600 cm soil layer.Soil moisture showed the overall trend that reduced first,then increased and gradually stable in the 0-600 cm soil layer in the fields with different growth years.The soil desiccation index ranged from 70.09%to 162.36%,the average thickness of the desiccated was 283.33 cm,presenting the moderate and mild drying intensities.The canonical correlation analysis showed that environmental factors such as latitude,longitude,growth years,silt and sand content were the significant factors affecting soil desiccation index and thickness of the desiccated layer.