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 rational ploughing method of “deep turning and stubble,，tightly lifting and lowering loose” suitable for rapeseed seedbed was proposed to solve the problems caused by the traditional mechanical plowing in the middle and lower reaches of the Yangtze River,，the use of traditional mechanical plowing resulted in thinning of the plough layer，hickening of the plough bottom layer and soil compaction affecting rape root growth. Combined the requirements for the construction of a reasonable plow layer of rapeseed and the up-and-down rotation tillage operation,，combined farming operation scheme combining active opposed plowing and rotary tillage was designed. A driven plough-rotor with a function of cutting and turning stubble (grass),，rotary ploughing，and levelling trenches was developed. The structural layout of the driven disc plough and the type and row of rotary ploughs were determined. And the imitated boot-shaped acute-angle groove opener was developed for the middle groove. Field experiments showed that the driving plough-rotary tiller had a tillage depth of 150~230mm,，and the stability of the tillage depth was 90.4%. The imitated boot-shaped acute angle opener could open a trapezoidal groove that met the requirements in the middle open trench area. The groove width was 200~400mm and the groove depth was 205.6~250.0mm. The flatness of the cabin surface was 15.25~18.60mm,，the soil crushing rate was 80.52%~88.43%，the rate of vegetation coverage was 92.3% and the single width of the cabin surface was 852~956mm after the prototype machine operation,，which met the requirements for the reasonable cultivation layer construction of the rapeseed bed and the water and dry rotation cultivation.