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

Northern region wheat and corn were taken as the research main bodies, and the field of Da Xinfeng village in Cuicun Town, Changping District, Beijing was taken as an example, the parameters of precision fertilization decision-making system was researched and corresponding mathematical model was established, the algorithm model and the database were unified, linear regression method to calculate fertilizer needed like N, P, K of soil was used. Two-dimensional interpolation method was applied to calculate unknown point of the region with the test samples in the region, thus soil fertility information database was established. Through the above ways and combined with the soil nutrient, crops type and the target yield and so on, the fertilizer needed of the region was determined, which could provide theory basis for circulation agriculture. 