Studies in soil cultivation. II. A test of soil uniformity by means of dynamometer and plough

Measurements are recorded of soil resistance to ploughing, taken with a view to testing the uniformity of a soil over a single field. The results have been examined for significance and indicate large variations over short distances. The differences have been represented by means of isodyne contours (i.e. lines of equal drawbar pull), drawn on a map.

The importance is emphasised of assuming and allowing for such variations before drawing conclusions from the drawbar pull recorded by different implements.

Preliminary work is described showing that the variations are correlated with clay content and also with the growth of a crop in its early stages.