广西山丘坡地土壤墒情时空变异特征及时间稳定性分析

Analysis on Spatiotemporal Variability and Temporal Stability of Soil Moisture in Hillslope Areas of Guangxi

广西较多耕地属于山丘坡地,土壤非均质性和地形起伏造成了耕地墒情具有较强的时空变异性,给田间尺度的墒情监测和管理带来了极大的困难。以广西崇左60个试验小区2017年定期采集的TRIM管土壤墒情数据为研究对象,统计了其时间和空间维度的变异性,分析了土壤墒情时空变异性与相关因素的关系,研究了土壤墒情的时间稳定性。结果表明,广西山丘坡地年平均土壤含水量在0.10~0.60之间变化,与地形、土壤质地等因素有较大的关系;坡地空间平均土壤含水量随时间在0.21~0.30之间波动,且与降雨和蒸发等气象条件密切相关,9-11月有较大概率出现土壤水分胁迫。时间稳定性分析表明3-2号试验小区观测的土壤含水量可以较好地代表整个坡地的平均土壤墒情。研究结果表明,广西山丘坡地土壤墒情有强烈的时空变异特征,变异统计、相关性分析、时间稳定性分析等工具可以用于广西山丘坡地土壤墒情的变异性评价和观测点优选。

Most of the cultivated land in Guangxi is located at hillslope with complex terrain.The heterogeneity of soil and the undulation of terrain result in the strong spatial and temporal variability of soil moisture,which leads to a severe difficulty for soil moisture monitoring and management.Based on the soil moisture data collected via TRIM in 2017 from 60 experimental plots in Chongzuo,Guangxi,this paper analyzes the spatial and temporal variability of the soil moisture,and its correlation with related factors.Moreover,the temporal stability feature of the soil moisture is obtained.The results show that the annual mean soil moisture spatially varies from 0.10 to 0.60,which is closely related to the field terrain and soil texture.The temporal change of spatially-averaged soil water content,which ranges from 0.21 to 0.30,has a good relationship with rainfall and evaporation and other meteorological conditions,and there is a great probability of soil water stress from September to November.The temporal stability analysis indicates that the No.3-2 experimental plot is the most representative location for representing the spatially-mean soil water for the site.It can be concluded that the soil moisture at this hillslope site has significant spatial and temporal variability,and the tools of statistics,correlation analysis,and temporal stability analysis can be employed to assess the soil moisture variability and optimize the soil water observation strategy.