Effectiveness of native wood strand mulches for land rehabilitation in Iran under experimental conditions

Abstract

AbstractWood‐based mulches are a preferred erosion control material for rehabilitation of degraded lands because they can be made from native wood materials; however, research is needed to verify the effectiveness of new products prior to application. The present study aims to assess the effectiveness of two types of native wood strand mulches from Iran (waste byproducts of Alnus glutinosa and Fagus orientalis working) in reducing runoff, soil loss, and sediment concentration under laboratory conditions. Toward this goal, rainfall simulations were conducted 27 times using a 50 mm hr−1 rainfall during 20‐min experiments on erosion plots with treatments of different cover percentages (bare, 30 and 70%) and strand dimensions (16 and 4 cm in length; 1.5 cm wide). The results showed that all strand applications reduced runoff (>12%), soil loss (>47%), and sediment concentration (>44%) compared to the bare plots. The most effective application treatment was a 70% coverage of the 4‐cm strands of either material (p value < .002). The shorter strands were most effective for all hydrological and erosion variables reductions because they maintained more contact with the soil surface during simulated rainfall and then increased the soil retention potential, whereas the longer strands realigned in the direction of flow, thereby limiting their ability to retard flowing water. The small strands also facilitated the creation of microdams that blocked flow and promoted infiltration. Both materials were deemed effective native erosion control products in degraded sites in the Hyrcanian forests of Iran, particularly when small strands were applied at high cover rates.