Investigations were carried out on five different soils at different moisture conditions. Soil resistance was measured with a hydraulic dynamograph on a single bottom plough operated with a tractor at 20-22 cm depth with a width of 60 cm.On light soils (sandy and loess soils) the soil resistance to ploughing was relatively small. The amplitude of instantaneous soil resistance measured from the mean value was also small. In the heavy loam soils, these variations were high. The highest instantaneous as well as the total soil resistance were found on the soil made of limy rock soil with a low organic matter. The magnitude of instantaneous soil resistance increased considerably with soil drying. The tillage tools must, therefore, overcome this short duration of high soil resistance. Such factors should be taken into consideration while designing new tillage tools.