ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

A typical peak-cluster depression area was selected as the study area. Based on the relationships between total soil nitrogen content in 0~20cm depth and terrain attributes by multiple linear stepwise regression method, the spatial variability of total nitrogen was studied by ordinary Kriging (OK), univariate Cokriging (COK) and multivariable Cokriging (MCOK) methods. Results showed that the spatial distribution of total nitrogen can be described by two regression models. Distance from ridge of mountains (VDFR) entered into the regression equation for the model (1), and distance from ridge of mountains (VDFR) and relief degree of land surface (VRS) entered into the regression equation for the model (2). Therefore, VDFR was selected as auxiliary variable to predict total nitrogen by COK method, and VDFR and VRS were selected as auxiliary variables to predict total nitrogen by MCOK method. The Kriging interpolation indicated that when the correlation coefficient between total nitrogen and terrain attributes was small, the accuracy of COK was increased litter. While MCOK can promote the accuracy notable. This study can provide a new idea and method for evaluation and ecological reconstruction of the karst rock desertification.