Chapter 5 5.4 Land degradation -Soil erosion ()Types of land degradation (2) Classification of soil erosion ()Climate and soil erosion (4) Soil erosion models (5 Erosion and productivity (6) Rainfall factor for soil erosion model 2021/2/22 Assessment of climate/Change Impacts I of 56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 1 of 56 5.4 Land degradation --Soil erosion (1) Types of land degradation (2) Classification of soil erosion (3) Climate and soil erosion (4) Soil erosion models (5) Erosion and productivity (6) Rainfall factor for soil erosion model
Chapter 5 Types of land degradation Desertification Soil erosion water erosion and wind erosion Salinization/alkalization Soil pollution 2021/2/22 Assessment of climate/Change Impacts 2of56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 2 of 56 (1) Types of land degradation • Desertification • Soil erosion: water erosion and wind erosion • Salinization/alkalization • Soil pollution
Chapter 5 (2) Classification of soil erosion Zachar, 1982. By erosive agents Water erosion Wind erosion Earth erosion Glacial erosion Anthropogenic/accelerated erosion Organic soil flow, snow 2021/2/22 Assessment of climate/Change Impacts 3of56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 3 of 56 (2) Classification of soil erosion Zachar, 1982. By erosive agents • Water erosion • Wind erosion • Earth erosion • Glacial erosion • Anthropogenic/accelerated erosion • Organic, soil flow, snow
Chapter 5 (2) Classification of soil erosion Zachar, 1982 By erosion form Precipitation/water erosion Surface erosion Underground erosion River erosion Lake and sea erosion Wind erosion Deflation Wind corrasion 2021/2/22 Assessment of climate/Change Impacts 4of56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 4 of 56 (2) Classification of soil erosion Zachar, 1982. By erosion form Precipitation/water erosion • Surface erosion • Underground erosion • River erosion • Lake and sea erosion Wind erosion • Deflation • Wind corrasion
Chapter 5 (2) Classification of soil erosion Precipitation/water erosion Surface erosion(American) Sheet, gully, stream/river(Ayres, 1936) Sheet, rill, gully, rock(Bennett 1939) Sheet, internal, channel(rill, gully stream)(Kohnke and Betrand, 1959) Interill, rill, ephermeral gully, gull 2021/2/22 Assessment of climate/Change Impacts 5of56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 5 of 56 (2) Classification of soil erosion Precipitation/water erosion • Surface erosion (American) ➢ Sheet, gully, stream/river (Ayres, 1936) ➢ Sheet, rill, gully, rock (Bennett, 1939) ➢ Sheet, internal, channel (rill, gully, stream) (Kohnke and Betrand, 1959) ➢ Interill, rill, ephemeral gully, gully
Chapter 5 (2) Classification of soil erosion Precipitation/water erosion(Russians) Washing, wearing(Kozmenko, 1954) Sheetrill),gully(Sobolev, 1948) Normal, accelerated( surface, rill, linear/gully Sus 1949) Water erosion(French) Washing: downpour, sheet, layer or strip, rill, wearing Mass removal: landslides, underground, mud flows, creeping 2021/2/22 Assessment of climate/Change Impacts 6of56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 6 of 56 (2) Classification of soil erosion • Precipitation/water erosion (Russians) ➢ Washing, wearing (Kozmenko, 1954) ➢ Sheet(rill), gully (Sobolev, 1948) ➢ Normal, accelerated (surface, rill, linear/gully Sus, 1949) • Water erosion (French) ➢ Washing: downpour, sheet, layer or strip, rill, wearing ➢ Mass removal: landslides, underground, mud flows, creeping
Chapter 5 (2) Classification of soil erosion By erosion intensity Harmless/normal erosion Compensative erosion Tolerance erosion Harmful erosion(sheet, gully No erosion, insignificant erosion Slight erosion Moderate erosion Severe erosion Ⅴ ery severe erosion Catastrophic erosion 2021/2/22 Assessment of climate/Change Impacts 7of56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 7 of 56 (2) Classification of soil erosion By erosion intensity • Harmless/normal erosion ➢ Compensative erosion ➢ Tolerance erosion • Harmful erosion (sheet, gully) ➢ No erosion, insignificant erosion ➢ Slight erosion ➢ Moderate erosion ➢ Severe erosion ➢ Very severe erosion ➢ Catastrophic erosion
Chapter 5 (2) Classification of soil erosion Compensative erosion Erosion in which the rate of destruction equals that of soil formation Soil formation rate 90cm thick soil layer, 16,000a; Icm/178a (Kohnke and Bertrand 1959) 3cm/200-1000a,lcm/240a( Bennett195) Icm/100a (Kukal, 1964) Soil loss rate Normal erosion: 0. 1-0. 6 acre a(0r/ a, 25-128t/km-a)
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 8 of 56 (2) Classification of soil erosion Compensative erosion • Erosion in which the rate of destruction equals that of soil formation • Soil formation rate 90cm thick soil layer, 16,000a; 1cm/178a (Kohnke and Bertrand, 1959) 2-3cm/200-1000a, 1cm/240a (Bennett, 1955) 1cm/100a (Kukal, 1964) • Soil loss rate Normal erosion: 0.1-0.6 t/acre a (0.25-1.48t/ha a, 25-128t/km2 a)
Chapter 5 (2) Classification of soil erosion Permissible/tolerance erosion 1. 24-14.84t/ha a(Smith and Stamey, 1965) 6.75 t/ha a(Kohnke and Bertrand, 1959) 2021/2/22 Assessment of climate/Change Impacts 9of56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 9 of 56 (2) Classification of soil erosion Permissible/tolerance erosion 1.24-14.84t/ha a (Smith and Stamey, 1965) 6.75 t/ha a (Kohnke and Bertrand, 1959)
Chapter 5 (2) Classification of soil erosion By erosion development Depending on different erosion form Sheet Gull Intrasoil wash Tunnel Darst 2021/2/22 Assessment of climate/Change Impacts 10of56
Chapter 5 2021/2/22 Assessment of Climate/Change Impacts 10 of 56 (2) Classification of soil erosion By erosion development • Depending on different erosion form ➢ Sheet ➢ Gully ➢ Intrasoil wash ➢ Tunnel ➢ Darst