二、 Soil mechanical composition and texture () Soil mechanical composition (二) Soil texture 1. Concept: Soil texture-The relative proportions of the various soil separates in a soil 2. Classification of soil texture
(一） Soil mechanical composition （二）Soil texture 1.Concept: Soil texture-The relative proportions of the various soil separates in a soil. 2. Classification of soil texture 二、Soil mechanical composition and texture
(1)International classification The textural triangle is used to determine the soil textural name after the percentages of sand(2-0.02mm), silt(0.02-0002 mm), and clay (0.002 mm) are determined from a laboratory analysis The main criterion of classification Clay <15 is sand and loamy groups; 15%-25% is clay loam group; >25% is clay group. When soil contains silt>45%, soil will be called"silty"; When soil contains sand in 55%0-85%, called "sandy When soil contains sand>85%, called“ loamy sand”or“sand
(1) International classification： The textural triangle is used to determine the soil textural name after the percentages of sand (2-0.02mm), silt (0.02-0.002 mm), and clay (<0.002 mm) are determined from a laboratory analysis. The main criterion of classification： Clay <15% is sand and loamy groups; 15％－25％ is clay loam group; >25% is clay group. When soil contains silt >45%， soil will be called “silty” ； When soil contains sand in 55%-85%，called “sandy” ， When soil contains sand >85%，called “ loamy sand”or “sand
9 90 80 1西 /1 70 多 s60 50 sandy 2 40 clay 百8388古岁85° 30 loam clay loam 砂粒 clay loam 2402m) 20 loam silt 图43国际制土壤质地三角图 sai loa am 10 1,砂士及壤殄土2,砂壤3、壤土:4.粉壤 amy silt 5.砂粘壤6.粘壤7.粉粘壤8.砂粘土 Asan 9,坡粘土10.粉粘土11.粘士12.重粘士 多男方。多当方 te. %0 The U.S. Dept of Agri. (USDA
The U.S. Dept. of Agri. (USDA)
Soil texture 表4-6卡钦斯基土壤质地基本分类(简制) 质地组 质地名称 不同土壤类型的<0.01毫米粒级含量(%) 灰化土 草原土壤、红黄壤|碱化土、碱土 砂土 松砂土 0~5 0~5 紧砂土 5~10 5~10 5~10 壤土 砂壤 10~20 10~20 轻壤 20~30 15~20 中壤 30~40 30~45 20~30 重壤 40~50 45~60 30~40 粘土 轻粘土 50~65 60~75 40~50 中粘土 65~80 75~85 50~65 重粘土 >80
Soil texture 表 4－6 卡钦斯基土壤质地基本分类（简制） 质地组 质地名称 不同土壤类型的<0.01 毫米粒级含量(%) 灰化土 草原土壤、红黄壤 碱化土、碱土 砂土 松砂土 紧砂土 0～5 5～10 0～5 5～10 0～5 5～10 壤土 砂壤 轻壤 中壤 重壤 10～20 20～30 30～40 40～50 10～20 20～30 30～45 45～60 10～15 15～20 20～30 30～40 粘土 轻粘土 中粘土 重粘土 50～65 65～80 >80 60～75 75～85 >85 40～50 50～65 >65