摘要
The new sustainable tillage system needs new machines which are the combination of well accepted disc harrow and cultivator or chisel/ripper. To find the type of ripper shank we have done a research program with 7 different shape and size tools. The geometrical parameters were determined in laboratory, the performance （loosening effect, depth etc） and draft requirements were measured on loamy soil stubble field （the speed range： 2.5-7.5 krrdh）. Developing a combined evaluation system-based on performance and draft data-to select the most favorable shank type for our condition was found one which has the following features： the size of the point： rake angle = 25°, length = 240 mm, width = 80mm; the equation of the shank curve： y = axb, where a = 2-3.5 and b = 0.04-0.05.
