Hadas, A., Institute of Soils and Water, ARO, Bet Dagan, 50-250 Israel
Wolf, D., Department of Agricultural Engineering, The Technion, Israel Institute of Technology, Haifa 32-000, Israel
Rawitz, E., Faculty of Agriculture, The Hebrew University, Rehovot 76-100, Israel

A stepwise simulation procedure was developed to assess soil compaction produced by machinery traffic on moist soil. Initial bulk density and water content distributions, soil compressibility and tractor wheel sizes, weight distributions and two or four wheel drive options were used as input data. The results obtained include draft, induced compacting stress and consequent soil bulk density distributions in the soil. The predicted results were compared with field measured data. It was found that the predicted bulk densities were always higher than the observed ones by 3-9% and 1-5% at depths of 5 and 25 cm, respectively. Nevertheless, the results obtained from the model used are of great importance in formulating recommendations and operational decisions for various field operations and for specific machinery and implement selection aimed at obtaining required tilth while maintaining low compactive hazard. The predicted compaction levels being higher than the observed ones suggest the uppermost limit of compaction attainable and indicate the direction to be taken to improve the model. © 1986.