为明确不同种植模式下棉田土壤水分的分布特点，本研究在长期定位试验田中选取麦棉套作、麦后直播棉、棉花单作三种种植模式，通过空间网格法对全生育期内棉田土壤水分进行分析，探究不同种植模式对土壤水分分布的影响，以判断棉花在各个生育时期的需水特征。结果表明，土壤水分的空间分布具有一定的空间异质性，具体表现在:不同种植模式下棉花不同生育时期土壤水分半方差分析的决定系数均在0。92以上，且最佳拟合模型均为高斯模型;偏基台值/基台值(C/Sill)的比值大多在0。75以上，土壤水分的空间分布具有较强的自相关性;三种种植模式下土壤水分空间变程均大于实际采样间距20 cm，表明土壤水分具有空间变异特征。由土壤水分空间分布结果可知，麦后直播模式对棉田土壤水分的影响主要集中在10～50 cm 土层内;麦棉套作模式下，受麦棉共生期的影响明显，因扎根较深，其影响深度可达70 cm 土层处。综上可知，麦棉两熟种植模式改变了棉田土壤水分的时空分布特征，而土壤水分消耗量是决定其空间差异性的重要因素之一。本研究利用空间网格法取样并量化土壤水分，运用地统计学原理进行空间异质性分析，所得两熟种植模式棉花全生育期土壤水分的运动规律，可为两熟种植模式下棉田水资源的合理利用及智能化灌溉提供理论支撑。
Soil Moisture Distribution Characteristics of Cotton Fields under Wheat and Cotton Cropping System
To clarify the distribution characteristics of soil moisture in cotton fields under different plant-ing modes,three planting modes of wheat-cotton intercropping,direct-seeding cotton after wheat harvest,and monoculture cotton were selected in the long-term positioning test in field.The spatial grid method was used to measure the soil moisture in cotton fields during the whole growth period,in order to explore the influence of different planting modes on soil moisture distribution and try to determine the water requirement characteristics of cotton in various growth periods.The results showed that the spatial distribution of soil moisture had a cer-tain spatial heterogeneity,which was specifically manifested in:the determination coefficient of soil moisture semi-variance analysis at different growth stages of cotton under different planting modes were all above 0.92,and the best fitting model was Gaussian model;when the ratio of partial abutment value to abutment value(C/Sill)was above 0.75,the spatial distribution of soil moisture had a strong autocorrelation;the spatial vari-ation range of soil moisture under the three planting modes was larger than the actual sampling interval of 20 cm indicating the spatial variation characteristics of soil moisture.According to the spatial distribution of soil moisture,it was found that the influence of direct-seeding cotton after wheat harvest on soil moisture in cotton fields was mainly concentrated in the 10～50-cm soil layer.In the wheat-cotton intercropping pattern,the soil moisture was obviously affected by the wheat-cotton symbiosis period,and the impact could reach to the 70-cm soil layer due to the roots growing deeper.In summary,the double cropping system of wheat and cotton changed the temporal and spatial distribution of soil moisture in cotton fields,and soil moisture consumption was one of the important factors that determined the spatial differences.In this study,the law of soil moisture movement during the whole growth period of cotton in the double cropping pattern was explored by using the spatial grid method to sample and quantify soil moisture,and using the geostatistics to analyze the spatial het-erogeneity,which could provide theoretical supports for rational use of water resources in cotton fields and in-telligent irrigation in double cropping pattern.
Double cropping of wheat and cottonSoil moistureDistribution characteristicsSpatial-temporal heterogeneity
万方数据
维普
