The Influence And Improvement Of Rotary Cultivator’s Blades Shapes Characteristics On Tillage Erosion

Tillage erosion is an important source of soil erosion on slope,which has a significant impact on soil physical and chemical properties and fertility.The type and characteristics of tillage tools have a significant impact on tillage erosion.Rotary tillers are widely used in purple soil hilly areas,but research on tillage erosion by rotary tillers is still lacking.In this study,the magnetic tracer method was used to study the effects of rotary tiller tool parameters and tillage methods on the erosion of cultivated land on purple soil slopes,and blade modified were made based on this.The main results and conclusions are as follows:1.Effects of rotary tiller blades parameters and tillage methods on tillage erosion（1）Effect of rotary tiller blades shape on erosionTwo common rotary tiller blades（straight and lateral bending blades）were used for alternate contour and upward and downward tillage,and the average tillage erosion rate in descending order from 0.04 to 0.22 m·m^-1:contour at straight bending blades(9.23±4.25 t·hm^-2)>contour at lateral bending blades(8.39±4.29 t·hm^-2)>upward and downward at lateral bending blades(7.94±4.69 t·hm^-2)>upward and downward at straight bending blades(5.05±6.33 t·hm^-2).The tillage erosion rate of both tools showed that the contour tillage was higher than the upward and downward tillage,but the relationship of the erosion rate in the same tillage direction was reversed:for the contour tillage,the straight bending blades was greater than the side;The side bending blades is larger than the straight.This result indicates that tillage erosion is not only related to the tillage direction,but also affected by the shape of blades.（2）Impact of rotary tiller blades number on tillage erosionRotary tillers with three-leaf and four-leaf blades are respectively installed on each blade plate of the rotary tiller.The installation of four pieces is called four-leaf blades,which is 1/3 more than the area where the three-leaf blades contacts the soil.The average tillage erosion rates of the three-leaf and four-leaf blades were 10.46±3.39 t·hm^-2 and 7.94±4.69 t·hm^-2 respectively,after the two blades were tilled upward and downward at a slope of 0.04⁰.22 m·m^-1.The tillage erosion rate was reduced by 24.09%,indicating that for the lateral bending blades tillage upward and downward,the increase in the number of blades reduced the tillage erosion.（3）The effect of tillage direction on tillage erosionAfter using lateral bending blades of four-leaf blades for different tillage directions,and the average tillage erosion rate in descending order from 0.04 to 0.22 m·m^-1:upslope with tillage angle of 45°(9.36±4.59 t·hm^-2)>downslope(9.21±3.25 t·hm^-2)>upward(6.50±3.43 t·hm^-2)>downslope with tillage angle of 45°(-0.86±3.52 t·hm^-2).In a single tillage direction,the rate of tillage erosion on the downslope with tillage angle of 45°is the smallest,and the slope is the upslope with tillage angle of 45°,and the difference in tillage erosion rate in different tillage directions is obvious,which indicates that the tillage direction has a significant effect on tillage erosion.2.Evaluation of tillage erosion of modified rotary tiller bladesCompared with conventional rotary tiller blades,the modified blades have obvious change in shape and structure.After contour and upward and downward tillage by double blades,leaf type and hollow type bending blades at slope of 0.04⁰.22 m·m^-1,the average tillage erosion rate were 5.93±2.44 and 5.82±4.28 t·hm^-2,4.01±3.33 and 6.23±3.14 t·hm^-2,8.96±3.57and 4.70±2.64 t·hm^-2,respectively.In the contour tillage direction,the tillage erosion rate produced by the modified blades lowest;in the alternate tillage direction,the tillage erosion rate produced by the improved hollow type blades is smallest.Compared with conventional blades,the erosion rate of modified blades has decreased,which indicates that modified blades are indeed effective in slowing down the erosion of tillage.In terms of the degree of fragmentation,the new blades also have obvious effects,in which the degree of fragmentation of the soil by the rotary tiller with double bending blades has increased significantly,and the soil content with a particle size of less than 10 mm exceeds 65.33%.Therefore,it was proved that modified blades can significantly reduce tillage erosion and change soil physical and chemical properties.