SSA2
Steps in Soil Formation
土壤形成的步骤
Weathering of Parent Material
母材的风化
Addition of Organic Matter:
有机物的添加:
Horizon Development:
Horizon 开发:
Soil Maturation:
土壤成熟度:
Weathering: breaking down rocks and minerals into smaller particles
风化 : 将岩石和矿物分解成更小的颗粒
Types of Weathering:
风化的类型 :
• Physical
• 物理
• Chemical
• 化工
• Biological
• 生物
Importance in Soil Formation:
在土壤形成中的重要性 :
• Creates finer particles that mix with organic material to form soil.
• 产生更细的颗粒,与有机材料混合形成土壤。
• Influences soil texture and mineral composition.
• 影响土壤质地和矿物成分。
• Enhances nutrient availability for plant growth.
• 提高植物生长的养分利用率。
Types of Weathering
风化类型
• Physical weathering
• 物理风化
• Freeze –thaw 冻融
• Freeze – thaw 冻融
• Temperature differentials温差 – night/day, seasonal, fires
• 温差温差 – 黑夜/白天、季节性、火灾
• Disposition 处置of mineral 矿物salts盐
• 矿物 矿物盐盐的处置
• Abrasion磨损
• Abrasion 磨损
• Biological- plant roots
• 生物植物根
• Chemical weathering
• 化学风化
• Hydrolysis水解
• 水解水解
• Oxidation/reduction氧化 还原
• Oxidation/reduction 氧化 还原
• Carbonation碳化
• 碳化碳化
• Biological- secretion分泌 of organic acids有机酸
• 有机酸的生物分泌
Factors of Soil Formation
土壤形成的因素
Rocks and topography Plant and animal life Time exposed to environmental conditions
岩石和地形植物和动物生活 暴露于环境条件的时间
1. Parent material母材料 2. Climate 3. Organisms (Biota) 4. Topography地形 5. Time
1. 父材料 2.气候 3.生物体 (Biota)4.地形地形 5.时间
SSA3
Why are Soil Horizons Important?
为什么 Soil Horizons 很重要?
• Affect plant growth, water movement, and nutrient availability
• 影响植物生长、水分流动和养分可用性
• Help scientists understand soil development and land use suitability
• 帮助科学家了解土壤发育和土地利用适宜性
The main horizons are:
主要视野是:
• O Horizon (Organic Layer)有机层 humus
• O Horizon (Organic Layer) 有机层腐殖质
• A Horizon (Topsoil)表土
• A Horizon (Topsoil) 表土
• E Horizon (Eluviation Layer)淘出层
• E Horizon (Eluviation Layer) 淘出层
• B Horizon (Subsoil)底图
• B Horizon (Subsoil) 底图
• C Horizon (Parent Material)父材质
• C Horizon (Parent Material) 父材质
• R Horizon (Bedrock)基岩
• R Horizon (Bedrock) 基岩
Key Processes in Soil Formation
土壤形成的关键过程
Eluviation洗脱 Illuviation沉积 Podzolization灰化 Gleization潜育 Calcification钙化 Salinization盐渍化
Eluviation 洗脱 Illuviation 沉积 Podzolization 灰化 Gleization 潜育钙化钙化 Salinization 盐渍化
Importance of Soil Horizons
土壤层的重要性
Agriculture:
农业:
Topsoil is critical for farming due to nutrient availability
由于养分的可用性,表层土壤对农业至关重要
• Water Retention:
• 保水 :
• Subsoil (B horizon) affects how water moves through the soil profile
• 底土 (B 层) 会影响水在土壤剖面中的移动方式
• Soil Fertility:
• 土壤肥力 :
• organic matter and minerals impacts plant growth
• 有机物和矿物质影响植物生长
Human Impact on Soil Horizons
人类对土壤层的影响
• Deforestation: Removes organic matter, soil degradation
• 森林砍伐 :去除有机物, 土壤退化
• Erosion: Strips away topsoil, reducing fertility
• 侵蚀 :剥夺表层土壤,降低肥力
• Farming Practices: disturb soil horizons
• 耕作方式 :扰乱土壤层
Soil Profile
土壤剖面
shows the arrangement of horizons
显示水平线的排列
reflect the soil-forming processes
反映土壤形成过程
each horizon has different thickness and distinctness
每个地平线都有不同的 THickness 和 Distinctity
SSA4
Soil Texture
土壤质地
• What is Soil Texture?
• 什么是土壤质地?
• Describes the relative proportion of sand, silt, and clay particles in soil
• 描述土壤中沙子、淤泥和粘土颗粒的相对比例
• Texture Affects:
• 纹理影响:
• Water retention and drainage
• 保水和排水
• Aeration and root penetration
• 通气和根系渗透
• Nutrient availability
• 营养利用率
Impact on Soil Properties:
对土壤特性的影响:
• Poor at holding nutrients due to large pore spaces
• 由于孔隙空间大,难以保持营养
• Provides good aeration,
• 提供良好的通气性,
Silt
淤泥
Impact on Soil Properties:
对土壤特性的影响:
• Provides moderate nutrient retention
• 提供适度的营养保留
• Prone to compaction, which can limit root growth and water movement
• 容易压实,这会限制根系生长和水的运动
Clay
黏土
Impact on Soil Properties:
对土壤特性的影响:
• High nutrient-holding, fertile but hard to manage
• 营养高, 肥沃但难以管理
• Can become compacted and difficult for root penetration
• 会变得压实,难以根系渗透
SSA5
SSA5 系列
Bulk Density
堆积密度
Importance in Agriculture:
在农业中的重要性:
• Affects soil compaction root penetration and water infiltration
• 影响土壤压实、 根系渗透和水渗透
• High bulk density can limit root growth and reduce yields
• 高堆积密度会限制根系生长并降低产量
• Optimal bulk density is important for seedling emergence and nutrient uptake
• 最佳堆积密度对于幼苗出苗和养分吸收很重要
• Factors Influencing Bulk Density
• 影响堆积密度的因素
Soil texture质地 Organic matter Compaction
soil texture 质地有机物 Compaction
What Impacts Bulk Density?
什么会影响堆积密度?
Excessive Tillage:
过度耕作:
Heavy Machinery Use:
重型机械用途:
Livestock Poaching:
牲畜偷猎:
Removal of Organic Matter:
去除有机物:
Deforestation:
森林 砍伐:
Adding Organic Matter:
添加有机物:
Reducing Tillage:
减少耕作:
Using Cover Crops:
使用覆盖作物:
Using Soil Conditioners:
使用土壤调理剂:
Managing Soil Water Retention and Movement
管理土壤保水和移动
• How to Improve Water Retention:
• 如何提高保水性:
• Increase organic matter content
• 增加有机物含量
• Reduce tillage to keep soil structure
• 减少耕作以保持 土壤结构
• Use mulching to reduce evaporation
• 使用覆盖物减少蒸发
• How to Enhance Infiltration and Drainage:
• 如何增强渗透和排水:
• Avoid compaction
• 避免压实
• cover cropping
• 覆盖裁剪
• Use deep-rooted plants
• 使用根深蒂固的植物
SSA6
SSA6 系列
Colloidal Properties of Soil Particles
土壤颗粒的胶体特性
Types of Soil Colloids:
土壤胶体的类型:
• Clay minerals
• 粘土矿物
• Iron and aluminum oxides
• 铁和铝氧化物
• Humus
• 腐殖质
Importance:
重要性:
• Affect soil structure, water retention, nutrient availability, and buffering
• 影响土壤结构、保水、养分可用性和缓冲
capacity.
能力。
• Essential for plant growth and soil health.
• 对植物生长和土壤健康至关重要。
• Play a key role in cation exchange capacity (
• 在阳离子交换能力 (
Surface Charge: Water Adsorption: Cation Adsorption: Surface Area: bigger than sand or silt
表面充注量: 水吸附 : 阳离子吸附 : 表面积 : 大于沙子或淤泥
SSA7
Nitrogen (N):Essential for photosynthesis and vegetative growth
氮 (N): 对光合作用和营养生长至关重要
Yellowing of older leaves, slow growth
老叶变黄, 生长缓慢
Phosphorus (P): Vital for ATP, root development, and flowering
磷 (P): 对 ATP、根系发育和开花至关重要
• Involved in the formation of DNA,RNA, and cell membranes
• 参与 DNA、RNA 和细胞膜的形成
Purpling of older leaves, poor root development
老叶发紫, 根系发育不良
SSA9
Granite – Soil Characteristics
花岗岩 – 土壤特性
• Texture: Sandy, low clay
• 质地:沙质、低粘土
• pH: Acidic (pH < 6)
• pH:酸性 (pH < 6)
• Fertility: Low
• 生育率:低
Drainage: Excessively drained, drought-prone
排水: 过度排水,易受干旱影响
Basalt – Soil Characteristics
玄武岩 – 土壤特性
• Texture: Clayey, fine-textured
• 质地:粘土质,质地细腻
• pH: Neutral to alkaline (pH 6.5–8)
• pH:中性至碱性 (pH 6.5–8)
• Fertility: High
• 生育能力:高
• Water: High retention, potential drainage issues
• 水:高滞留,潜在的排水问题
Limestone – Soil Characteristics
石灰石 – 土壤特性
• Texture: Clayey to loamy; often shallow or rocky
• 质地:粘土质至壤土质;通常较浅或岩石状
• pH: Alkaline (pH 7–8)
• pH:碱性 (pH 7–8)
• Fertility: Moderate to high Ca/Mg, low P availability
• 肥力:中度至高钙/毫克, 低磷含量
• Water: well drained, but limited storage if shallow
• 水:排水良好,但如果浅,则存储空间有限
SSA10
SSA10 系列
What is Soil Degradation?
什么是土壤退化?
• the reduce of soil quality and function effectively in ecosystems and agriculture
• 有效地降低土壤质量并在生态系统和农业中发挥作用
• Caused by both natural processes and human activities
• 由自然过程和人类活动引起
• Leads to the loss of physical structure, nutrient content, biological activity, and water retention capacity
• 导致物理结构、营养成分、生物活性和保水能力的损失
• Degraded soils produce lower crop yields, require more inputs, and often lead to environmental problems
• 退化的土壤导致作物产量降低,需要更多的投入,并且经常导致环境问题
Types of Soil Degradation
土壤退化的类型
Physical degradation Chemical degradation Biological degradation
物理降解化学降解生物降解