The effects of organic mulches on recovery process in soil physical properties in the compacted soil in the skid trails (Case study: Kheyrud forest)

Various engineering measures, such as mulching, have been applied to skid trails to suppress the negative effects of surface runoff and flood hazards. However, study on the effectiveness of such treatments to restore soil properties is scarce. In this study, the effect of organic mulches including leaf litter, rice straw and sawdust on the recovery of physical properties of compacted soil of skid trails (i.e., soil bulk density, porosity, resistance to penetration and soil texture) was evaluated and tested two years after skidding operations compared to untreated trails and undisturbed (control) area. The results showed that the treatment of leaf litter mulch, rice straw and sawdust had a significant effect on the recovery of soil bulk density, porosity and soil penetration resistance, but had no significant effect on soil texture. The results showed that litter mulch has the greatest effect on the recovery of soil physical characteristics compared to straw and sawdust mulch. However, for two years, the soil texture was not affected by the type and amount of mulch. Also, in the surface depth, the effects of mulch are more significant. We can conclude that the applying different organic mulches increased levels of each mulch moderately ameliorated soil physical properties, after mechanized operations over a two-year period, compared to the untreated treatment; however, the values of soil properties were still lower than those in the undisturbed (control) area, indicating that two years is not long enough to restore the soil properties to pre-harvest levels in the study area.