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

Field experiments were conducted to study the effects of different water and nitrogen managements on nitrogen remobilization efficiency during maize leaf senescence process. The experiment included three irrigation levels (150m3/hm2, 300m3/hm2 and 450m3/hm2) and four nitrogen application levels (0kg/hm2, 180kg/hm2, 220kg/hm2 and 260kg/hm2). The date of onset of leaf senescence, maximum rate of decrease in relative green leaf area, mean rate of decrease in relative green leaf area and the day of maximum rate of decrease in relative green leaf area under different water and nitrogen conditions were analyzed. The effects of nitrogen remobilization efficiency and grain filling process during leaf senescence process were also studied. The results showed that the date of onset of leaf senescence under each treatment occurred about 10 days after silking, and it was less affected by irrigation and nitrogen application. Under sufficient irrigation conditions, increasing nitrogen application could reduce maximum rate of decrease in relative green leaf area and prolong the day of maximum rate of decrease in relative green leaf area. With the same amount of nitrogen application, leaf nitrogen accumulation was increased first and then decreased with the increase of irrigation at silking stage. Within a certain range, leaf nitrogen remobilization efficiency was increased with the continuous increase of the day of maximum rate of decrease in relative green leaf area, and the maximum increment was 25.78 percentage points. The grain filling rate was slow first, and then fast, and eventually tended to change smoothly. The grain filling rate reached the maximum value after 30~40 days of silking. Delaying leaf senescence rate was helpful to improve 100grain quality. When the amount of irrigation was 300m3/hm2 and the nitrogen amount applied was 260kg/hm2, the day of maximum rate of decrease in relative green leaf area occurred at 48.90 days after silking and both leaf nitrogen remobilization efficiency and 100grain quality were the highest. 