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 field information acquisition instrument to measure the soil pH value and electrical conductivity (EC) was designed. Based on the measurement theory and the software and hardware design of the instrument, the calibration test to the acquisition instrument measuring pH value and electrical conductivity by means of two-point and the standard KCl solution was carried out. Then 15 soil samples were taken from a piece of bean field with the sampling interval of 14m×14m. The validation test to the calibration equation was carried out. The results showed that the relative error between the calibration result and the accurate value for soil pH value is less than 1%, and the relative error between the calibration result and the accurate value for soil EC is less than 14%, the linear regression model significance probability of the soil pH value calibration results and exact value is 0.0478,R2=0.8978,the linear regression model significance probability of the soil EC calibration results and exact value is 0.0004,R2=0.9716,it is proved that the calibration equations of the pH value and EC are reliable.