Efficiency of the conservation treatments for soil erosion control from skid trails

Nowadays, study about the reclamation of abandoned skid trails is necessary due to the their frequency in forestry units of north of Iran especially in so-called respiration period. These skid trails turn to be bare after the primary transportation (especially within first transportation years) where resulted in erosion and damage to soil forest. The aim of this study was to determine the best conservation treatments to deal with skid trails’ water erosion.

Firstly, a skid trail with a minimum length of 500 meters was selected in Bahramnia’s forestry plan. The longitudinal slope was divided into slope classes of 20-40% and >40%. In each class a segment with a length of 126 meters was determined and treatments of ditch & embankment, ditch & slash and ditch & stone each of in length of 14 meters with 5 meters interval were implemented. A rubber bar was installed at the end of each segment to convert sediment and runoff in to collectors. Sampling was done after each rainfall during 4 months (autumn and winter 2019 and 2020). The Intensity – Duration rainfall information has been determined using Rain gauge in the location, then dry weight of sediment samples has been measured in laboratory.

Findings indicated that in both slope classes of 20-40% and >40% amount of runoff, sediment concentration and soil loss was significantly increased along with increasing intensity and duration of rainfall. In slope class of 20-40%, treatment of ditch and slash has more successfully done than other treatment in sedimentation and soil loss control than other treatments. In slope class of >40%, there wasn’t significant difference between the efficiency of treatments in sediment and soil loss control. Whereas, generally, treatments of ditch and slash as well as ditch and stone were more successful to control soil erosion than ditch & embankment treatment. In both slope classes, the rainfall intensity of 0.11 mm h-1 (2.64 mm in 24 h) was the threshold of water erosion of soil on skid trails. likewise, the interaction effect of slope and treatment type were not significant on runoff volume’s variables as well as sediment concentration and soil loss. Findings indicated that the ditch & slash treatment, in slope class of 20-40%, were the best in terms of sedimentation and soil loss control which could mitigate soil waste by 64%. In unallowable slope >40% all treatment could mitigate soil erosion by 47% which indicates the low efficiency of conservational treatments in unallowable slope tracks.

This research showed using of ditch & slash treatment cab be reduce soil erosion in skid trails, so consider to conservation the soil of skid tails this achievement has the applicability and generalizability