Generation of predetermined soil profiles in a soil bin

Abstract

The soil preparation in soil bins must be capable of generating a number of soil density profiles varying from uniform to heavily compacted layers lying below more friable soil. A subsurface rotating rod firmed the soil beneath the rod and repeated passes produced desired profiles. Retrofitting the existing instrumentation with virtual instrumentation methods resulted in measurements that were more precise and improved repeatability. A Wheatstone bridge force transducer measured Cone Index pressure as a function of soil penetration depth. Soil surface elevation and implement depths were located with ratiometric linear transducers. Speed and distance were measured with an optical encoder. Prime mover hydraulic oil temperatures and pressures were gauged with current loop sensors. Three Null Hypotheses were tested: a horizontal subsurface rotating rod will not cause an increase in soil cone index; repeated operation of the horizontal rotating rod will not result in increased soil cone indexes; and soil water content is not relevant to the resultant compaction level. The first two Null Hypotheses were rejected at the 5% level in the overall case although not in each case while the third Null Hypotheses was rejected at the 5% level in all cases.