
环境科学 第7讲土壤 北京大学环境科学与工程学院
北京大学环境科学与工程学院 1 第7讲 土壤

Soil and Its Uses 环境科学 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Soil and Its Uses 2

Outline 环境科学 ·Geologic Processes(地质作用) -Weathering ·Soil Formation(形成) ·Soil Properties(特征) ·Soil Profile(剖面构成) -Soil Horizons ·Soil Erosion(侵蚀) Soil Conservation (保护) -Tillage Practices(耕地) 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Outline • Geologic Processes(地质作用) – Weathering • Soil Formation(形成) • Soil Properties(特征) • Soil Profile (剖面构成) – Soil Horizons • Soil Erosion (侵蚀) • Soil Conservation (保护) – Tillage Practices(耕地) 3

Geologic Processes 环境科学 ● Crust(地壳)-Extremely thin,less- dense solid. ·Mantle(地幔)-Makes up majority of earth,and surrounds a small core of iron. -Outermost portion is solid. Crust and solid outer mantle collectively known as the lithosphere(岩石圈). -Asthenosphere(岩流圈)isa thin layer below the outer mantle capable of plastic flow. 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Geologic Processes • Crust (地壳)- Extremely thin, lessdense solid. • Mantle (地幔)- Makes up majority of earth, and surrounds a small core of iron. – Outermost portion is solid. • Crust and solid outer mantle collectively known as the lithosphere(岩石圈). – Asthenosphere (岩流圈)is a thin layer below the outer mantle capable of plastic flow. 4

气圈 环境科学 Gas-sphere 生物圈 生物养分 土壤图 水分循环 水圈 Biosphere pedosphere 与 Water sphere 质 衡 环 金属与微量元素物质循环 岩石圈 Rocky-sphere 土壤圈的作用(position of pedosphere) 汇程学院
土壤圈的作用(position of pedosphere) 北京大学环境科学与工程学院 气圈 Gas-sphere 岩石圈 Rocky-sphere 水圈 Water sphere 生物圈 Biosphere 土壤圈 pedosphere 金属与微量元素物质循环 生 物 养 分 物 质 循 环 水 分 循 环 与 平 衡

Structure of the Earth 环境科学 Continental crust Uppermost mantle 100km h8opi 200km downward Outer core 学院
北京大学环境科学与工程学院 Structure of the Earth 6

Geologic Processes 环境科学 ·Plate Tectonics(板块构造论)-Large plates of crust and outer mantle slowly moving over surface of the liquid outer mantle. -Heat from earth core causes movement. Plates are pulling apart in some areas,and colliding in others. Building processes counteracted by processes tending to tear down land 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Geologic Processes • Plate Tectonics (板块构造论)- Large plates of crust and outer mantle slowly moving over surface of the liquid outer mantle. – Heat from earth core causes movement. • Plates are pulling apart in some areas, and colliding in others. • Building processes counteracted by processes tending to tear down land. 7

Tectonic Plates 环境科学 CopyrightThe MeGraw-Hill Companies Inc.Perm d for reproduction or display on 135 180 135 ctic plat 180 135 90 Direction of plate moti sawteeth point toward Spreading ridge overriding plate) Transform fault
北京大学环境科学与工程学院 Tectonic Plates 8

Geological Processes 环境科学 Weathering(风化)-Factors bringing about fragmentation or chemical change of parent material. -Mechanical-机械物理作用Results from physical forces reducing size of rock particles without changing the chemical nature of the rock. ·Freezing and Thawing Cycles((冻融作用) ·Erosion from Wind and Moving Water(风蚀与 水蚀) 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Geological Processes • Weathering (风化)- Factors bringing about fragmentation or chemical change of parent material. – Mechanical – 机械物理作用Results from physical forces reducing size of rock particles without changing the chemical nature of the rock. • Freezing and Thawing Cycles(冻融作用) • Erosion from Wind and Moving Water(风蚀与 水蚀) 9

Physical Fragmentation 环境科学 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Physical Fragmentation 10