Soil compaction in forest soils

Soil compaction is a widespread degradation process in forest sites. Soil degradation occurring on the structural formation of a natural soil system by rainfall or mechanical outer forces generally results in soil particles to be rearranged tighter than its previous status. In this case, soil compaction -defined as the increase in bulk density of soil- develops with negative effects on soil-plant-water relations. With the compaction, the density of soil increases while the porosity rate decreases, creating a harder formation in soil and consequently lower degree of hydraulic conductivity. Higher soil compaction usually occurs in densely used places including recreational areas, settlements, logged forests, fruit gardens, agro-forestry systems and nurseries. The compaction may occur naturally, but it can also be started by outer factors such as soil preparation tools, heavy equipments, tire traffic, livestock grazing or fires. Besides causing deterioration on physical and hydrological features in growing environments of plants, soil compaction may also lead to physiological degradation of plants and changes on the balance and amount of growth hormones of plants, which, in turn, may limit nutrient uptake. In this study, possible reasons for compaction problem observed in forested soils and its negative effects on soil physical, chemical and microbiological characteristics as well as on the physiology of plants were evaluated.