Studies in soil cultivation. I. The evolution of a reliable dynamometer technique for use in soil cultivation experiments

An account is given of a reliable technique that has been evolved for making dynamometer measurements in the field. It has been shown that quite small variations in the trace of the drawbar pull are significant, and correspond to actual variations in the resistance of the soil. No significant change in drawbar pull is produced by imperfect adjustments in the hitch or set of the implement within the limits met with in ordinary ploughing, except in so far as the depth of working is affected. The drawbar pull bears a linear relationship to ploughing depth within the region of ordinary ploughing. The slope of the land is without appreciable effect on the drawbar pull up to gradients of 1 in 40.