Terracing as a Measure of Soil Erosion Control and Its Effect on Improvement of Infiltration in Eroded Environment

Abstract

Soil erosion by water is commonly recognized as the one of main reasons of land degradation worldwide (e.g. Ananda & Herath, 2003; Beskow et al., 2009; Valentin et al., 2005). Most of the involved areas are occupied by various agricultural activities but pastures, forestry, unpaved roads as well as construction sites are also endangered by water erosion (Ananda & Herath, 2003; Arnanez et al., 2004; Harbor, 1999; Jungerius et al., 2002). Exemplary, in Europe, excluding European part of Russia, human-induced soil erosion develops on approximately 114 milion hectrares, which is 17 % of total land area (Gobin, 2004). According to information presented by Pimentel and Kounang (1998) more than 80% of world’s agricultural land suffers soil erosion, from moderate to severe level. The mean noted yearly soil erosion rate on cropland worldwide reaches the level of approx. 30 Mg ha-1, while reported values vary from 0.5 to over 400 Mg ha-1 yr-1 (Pimentel & Kounang, 1998). Soil erosion rates, caused by water, are highest in agrosystems located in hilly or mountainous regions of Asia, Africa and Southern America, especially in less developed countries. According to studies reported by Kuhlman et al. (2010) construction sites in Europe are endangered by soil erosion rate higher than 2.0 Mg ha-1 yr-1, while soil erosion rate noted on approx. 70% of European arable lands is lower than 0.5 Mg ha-1 yr-1 or ranges from 0.5 to 2.0 Mg ha-1 yr-1. Several factors influencing the rate of soil erosion by water were reported (e.g. Amore et al. 2004; Askoy and Kavvas, 2005; Basic et al., 2004; Zhang et al., 2008): Climatic conditions: precipitation, frequency of extreme rainfall events and thickness of snow cover as well as rate of its melting; Terrain surface morphology determining the rate of surface runoff generation and flow velocity: hillside slopes’ length, inclination and exposure; Soil characteristics: its particle size composition and erodibility; Soil usage: manner of agricultural, forestry, engineering or constructional activities. Soil erodibility is understood as a measure of its susceptibility to detachment and transport by water (Hammad et al., 2006). Among soil characteristics several properties influencing erodibility may be determined: aggregate stability, organic matter and clay particles content. Various types of soil erosion may be triggered by rainfall, thaw and runoff water: sheet, rill, and gully erosion (Askoy & Kavvas, 2005; Gronsten & Lundekvam, 2006; Valentin et al.,