Multipass effects of wheel and track type vehicles on soil compaction
A field study was conducted in the fall of 1982 to investigate the effect of vehicle type, traffic moisture level, and their interactions on soil compaction. During the study two procedures commonly used for soil bulk density determination were also compared.
Treatments at the following levels were applied:
i) Soil moisture: Two levels
ii) Vehicle type: wheel and track type
iii) Traffic intensity: 0, 1, 3, and 9 passes.
Each treatment combination was replicated three times and these were installed in random order on 48, 6 x 30 m test plots.
Soil samples were taken at three locations from each test plot for the determination of moisture level. Core samples were taken in and outside the rut at three locations along each track for bulk density determination. Bulk density data using a double probe nuclear densitometer were taken at one location along the track.
Statistical analysis of the data indicated that, of the factors considered in the study, number of vehicle passes and interactions between moisture level and vehicle type and number of passes and vehicle type had a significant effect on the compaction of the top soil layer. The two methods for measuring soil density were compared using the paired student's t-test and an equation was developed relating the density values obtained by nuclear and gravimetric procedures. Comparison of the data from the two methods indicated that the nuclear densitometer underestimated the core bulk density.