东北地区土壤温度和湿度空间变异特性研究

于2015年4月在黑龙江农垦赵光农场，使用20套无线传感器网络节点部署在赵光农场一面积为33.4 hm 2 的玉米地块，并通过2个手持式移动节点进行加密测量。根据这一方案，获得了从4月5—29日在240 m×240 m、120 m×120 m、60 m×60 m和30 m×30 m网格下的土壤温度和土壤湿度数据。在此基础上，基于统计半方差函数理论和GIS空间Kriging插值方法分别分析了土壤温度和土壤湿度各向同性、各向异性变化特征及分布模式。结合土壤温度和土壤湿度在不同尺度下的Kriging插值结果，确定了两者最佳采样间距。试验结果表明，土壤温度和土壤湿度的半方差函数分别适用于球形模型和指数模型，两者均有很强的空间自相关。其中，土壤温度自相关距离为51.56 m，土壤湿度的自相关距离为154.16 m。土壤温度在45°、90°方向变化明显大于0°、135°方向；土壤湿度拟合决定系数( R 2 )为0.77，在0°、135°方向上变化较大，土壤温度和土壤湿度最佳采样间距分别为60 m和100 m。

Spatial Variability of Soil Temperature and Moisture in Northeast China

In order to achieve the maize sowing time decision-making and improve the effective accumulated temperature of maize growth, it is needed to understand the soil spatial variability characteristics. Totally 20 sets of wireless sensor network nodes were deployed in Zhaoguang Farm in Heilongjiang Province for one month in 2015. In addition, two handheld mobile sensor nodes were chosen to increase the measurement number. According to the method, soil temperature and moisture data were obtained from 5 th to 29 th in April with 240 m×240 m, 120 m×120 m, 60 m×60 m and 30 m×30 m grids. The isotropic and anisotropic variation characteristics and distribution patterns of soil temperature and moisture were analyzed based on statistics semivariance function theory and GIS space Kriging interpolation method. Experimental results showed that the semivariance of soil temperature and moisture were suitable for the spherical model and exponential model, respectively. Both of them had strong spatial autocorrelation. The distribution of soil temperature was block with autocorrelation distance of 51.56 m. And the distribution of soil moisture was ribbon with autocorrelation distance of 154.16 m. The anisotropy of soil temperature and moisture variation was also significant. The soil temperature variations in 45° and 90° directions were significantly greater than those in 0° and 135° directions. The soil moisture determination coefficient ( R 2 ) was 0.77 with significant variations in 0° and 135° directions. The research results provided a scientific guidance for the decision-making of maize seeding time and the determination of soil sampling distance.