Soil cutting and tillage

angle of internal average calculated chisel plow clay loam clay soil cm depth contact area contact length contact pressure critical depth crop cutting forces Deere & Company deformation depth to width diameter draft force drawbar effective efficiency energy factors Godwin and Spoor Grisso horizontal hydraulic conductivity implement increase internal friction kPa/mn load machine maximum McKyes measured Mohr's circle moisture content moldboard plow narrow tools normal stress operation parameters particles percent plane plates predicted Raghavan rolling resistance sand shank shear strength shear stress shown in Fig sinkage soil compaction soil cutting soil cutting tool soil density soil dry density soil failure soil loosening soil mechanics soil stiffness soil strength soil structure soil surface subsoiler Table Terramechanics tillage tillage tools tool rake angle tool width traction force tractor values vehicle vertical volume of soil wedge weight wheels wheelslip width ratios