Design and experiment of testing device for soil working tool in no-tillage planter

Abstract: Ridge culture can slow down the runoff of rain and prolong the infiltration time of rain, it plays a role on intercepting rain and protecting soil; furthermore, it could increase the cultivated area, thicken the soil layer which close to crop root system, make it easy to receive the illumination, improve the temperature of ground surface, benefit growth and promote the maturity of crops. The corn ridge culture no-till planter from Northeast China exists many problems so far, such as too large equipment quantity, destroying ridge shape while operating, serious compaction of soil, thicken the plow pan, caused deterioration of physiochemical properties of arable soil and fertility decline. In order to optimize the design soil work tool of no-till planter, the domestic and overseas development states of soil work tool testing device was analyzed, and combined with the situation of corn conservation tillage in Northeast China, the testing device of soil work tool was researched, designed and manufactured. The testing device could be applied to different farming methods, different ridge distances and variety of soil working tools. The testing device is a mounted device, which mainly composes of force measurement framework, four-bar profiling mechanism, pull pressure sensor, angular displacement sensor, linear displacement sensor and soil work tool fixture. There are two pull pressure sensors installed on and below the four-bar profiling mechanism, angular displacement sensor installed on the axis of rotation; soil work tool fixed to the force measurement framework with linear displacement sensor on it. It will detect the up and down displacement change of force measurement framework while testing (scilicet the change of the entering soil depth of work tool). Given the resultant force F of upper and lower link and the gravity G of testing device, the working resistance R of soil work tool can be calculated. F, G and R meet at one point, formed a balanced system of force. The data collecting card will collect testing data, which will be sent to computer in time. Computer software could record data accurately and display dynamic data waveforms. It can determine working resistance (size, orientation, focus) of the soil working tool, working depth and additional weight of machines by processing the data which obtained from test results, and provide reference for optimal design of soil working tool. Through test the working performance of Archimedes spiral disc cutting knife which is soil working tool, concluded that working resistance for breaking the corn stubble on the root is 1868.38 N, force direction angle is 67.66 degrees, stubble cutting depth is 7.52 cm, the distance between line of action and center of soil work tool is 4.59 cm, the total weight of devices and additional weight should be greater than 175.79 kg. On this basis, through analyze the time-dependent graphs of disc cutting knife working resistance, which include horizontal component Rx that against the advancing direction of test device and vertical component Ry that perpendicular to ground, obtained a mechanism that image of cutting time and cutting resistance when disc cutting knife cutting corn stubble, which laid a foundation and experimental verification for load specific property of no-tillage planter.