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

The growing degree days can reflect the comprehensive influence of climatic conditions on crop growth and analyze the thermal conditions of crops. It is used to determine the suitable sowing time, growth period and corresponding physiological growth characteristics of crops under a certain climatic conditions. Usually, growing degree days are defined as the sum of the growing degree days by a crop during its growth period. The growth characteristics of potatoes in different regions were systematically researched, and the universal growth models of the growth indexed with growing degree days as independent variable growing degree days were established, the leaf area index (LAI), dry matter accumulation of whole plant and dry matter accumulation of tuber were chosen as the main growth indexes. The results showed that the corresponding growth rate of the leaf area index, the dry matter’s accumulation capacity in the whole plant and the dry matter’s accumulation capacity in tubers were respectively increased to a maximum value when growing degree days reached 600℃ (tuber formation stage), 900℃ (early stage of tuber expansion) and 1100℃ (late stage of tuber expansion). In addition, the growth rate of LAI in potato seedling stage and tuber formation stage (growing degree days was less than 900℃) was higher than that of tuber dry matter accumulation, while the growth rate of tuber dry matter accumulation in tuber expansion period (growing degree days was greater than or equal to 900℃) was higher than that of LAI. The growth process of LAI, dry matter accumulation of the whole plant and tuber dry matter accumulation all had “S-shaped” changing curve with “slowerfasterslower” characteristics, which meant that the index growth curve conformed to the Logistic growth model. The Logistic growth model was used to quantitatively analyze the process of potato LAI, dry matter accumulation of the whole plant and tuber dry matter accumulation, it indicated that the model can be used to describe the changing process of potato main growth indexes. The results can not only provide a scientific basis for the rational selection of suitable sowing dates and longterm management of potatoes, but also provide a reference for the effective utilization of local natural climate conditions to achieve high yield and efficiency.