Soil criteria for assessing the maximum permissible ground pressure of agricultural vehicles on Chernozem soils

The maximum permissible ground pressure of agricultural vehicles to permit satisfactory crop production on heavy loamy Chernozem soil was estimated from six criteria: (1) changes in soil water-physical properties; (2) crumbling characteristics; (3) depth of compaction; (4) rut depth; (5) soil strength potential; (6) self-loosening characteristics. Using these criteria it was possible to obtain reliable data for the maximum permissible ground pressure which was found to be correlated with the soil water content at the time of tillage. At a water content equal to or somewhat lower than the water content at optimal soil crumbling (0.16-0.24 kg kg(-1)), the permissible ground pressure was found to be within the range 80-120 kPa. At soil water contents slightly above the optimum soil crumbling (0.26-0.28 kg kg(-1)), the permissible ground pressure was within the range 30-60 kPa.