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

On the basis of SPAD model for nutrition diagnosis of nitrogen fertilization, we determined the optimal nitrogen rate at the different growth stages of cotton with drip irrigation under mulch. Combining with relevant research at a single irrigation time and acreage of round irrigated area, we definited the fertilizer time of different specifications fertilizer disc. The capacity of the device with combined application of nitrogen fertilizer was determined by comparing with distribution and application of combined fertilizer at unit time. The results showed that the rate of fertilization per unit time for the device was related to water yield from any single well and nitrogen fertilizer in the whole cotton growth period, and the device were unable to meet the needs of topdressing when it used fertilizer disc of sizes with 100g, 200g and 300g. Furthermore, fertilizer disc of sizes with 400g and 500g could only meet topdressing nitrogen level of cotton under condition of the specific water yield from a single well. And according to our research described above, we explored the approach to optimize and improve device.