CHAPTER 12 SOIL TILLAGE AND MANAGEMENT
CHAPTER 12 SOIL TILLAGE AND MANAGEMENT
Section l Concept of soil tillage and basic manipulation 、 Concept of soil tillage Tillage- The mechanical manipulation of the soil profile for any purpose Soil tillage-oldest procedure of agriculture to manipulate the soil to improve crop production Farmers of West Africa preparing their land for planting
Section1 Concept of soil tillage and basic manipulation 一、 Concept of soil tillage Tillage- The mechanical manipulation of the soil profile for any purpose. Soil tillage - oldest procedure of agriculture to manipulate the soil to improve crop production. Farmers of West Africa preparing their land for planting
Tillage-Modern
Tillage - Modern
Tillage uses more energy than any other cropping procedure Tillage requires time since lifting the soil and moving it can not be done rapidly
• Tillage uses more energy than any other cropping procedure. • Tillage requires time, since lifting the soil and moving it can not be done rapidly
Tillage-Objectives: (1) Preparation of seedbed (2)Control of weeds (3)Fluff soil -reduce bulk density of root zone (4)Soil and Water conservation 犁梁 图122各种无壁犁和松土铲 片上装上犁 柱即为深松土犁 铧翼 犁侧板后踵 胫刃 犁铧 犁铧切削刃 犁铧胫板 铧尖 图12-1铧犁主犁示意图 图12-3铰链耙架尖齿耙
Tillage – Objectives: (1) Preparation of seedbed (2) Control of weeds (3) Fluff soil - reduce bulk density of root zone (4) Soil and Water conservation
Basic manipulation of tillage 、 Plowing 框架总成 提升臂 平行提升连杆 2、 Preparation of soil 3、 Intertillage 通用机架 4 Other tillage manipulation 铲柱或 铲柄 部件 两个单独机组 图12-5旋耕机 图124中耕机
二、 Basic manipulation of tillage 1、Plowing 2、Preparation of soil 3、Intertillage 4、Other tillage manipulation
Section 2 Mechanics natures of soil a Soil coherence The natures of soil coherence Van der Waals force, hydrogen bond coulombian force. and water membrane surface tension. 230B 词20 Affect the factors of soi coherence a 一-+.4 水分(%) 1 Soil specific surface and its affect the factors 图126土壤水分含量与粘结力的关系 曲线C的粘结力单位为:克英寸 2 Soil moisture content (1英寸=2.54cm)
Section 2 Mechanics natures of soil 一、Soil coherence The natures of soil coherence: Van der Waals force, hydrogen bond, coulombian force, and water membrane surface tension. Affect the factors of soil coherence ： 1、Soil specific surface and its affect the factors 2、Soil moisture content
表12-1各种土壤的粘结力 及对铁片的粘着力( Schubler 干土的相对粘结力湿土对铁片的粘着 土壤 (以灰色纯粘土作 力 为100) (磅/英尺2) 硅质纯砂土 0.0 3.8 2.腐殖质 8.7 8.8 3菜园土 7.6 4砂粘土 57.3 7.9 5壤粘土 68.8 106 6灰色纯粘土 100.0 17.2
表12－1 各种土壤的粘结力 及对铁片的粘着力 (Schubler) 土 壤 干土的相对粘结力 (以灰色纯粘土作 为100) 湿土对铁片的粘着 力 (磅/英尺2 ) 1.硅质纯砂土 2.腐殖质 3.菜园土 4.砂粘土 5.壤粘土 6.灰色纯粘土 0.0 8.7 7.6 57.3 68.8 100.0 3.8 8.8 6.4 7.9 10.6 17.2
二、 Soil adhesivit!y 三、 Soil plastic Plastic -A soil capable of being molded or deformed continuously and permanently, by relatively moderate pressure, Into various shapes. 原来的杂乱排列 揉捏后的平行排列 图127片状粘粒塑性的显现
二、Soil adhesivity 三、Soil plastic Plastic –A soil capable of being molded or deformed continuously and permanently, by relatively moderate pressure, into various shapes
The liquid limit is the gravimetric moisture content at which the soil changes from being plastic and starts to behave as a viscous liquid The plastic limit is the gravimetric moisture content at which a soil changes from being friable' into being plastic The plasticity index is defined as the difference between he liquid and plastic limits. Atterberg limits- The collective designation of five so called limits of consistency of fine-grained soils, suggested by Albert Atterbrg, 1911-912, but with current usage usually retaining only the liquid limit, the plastic limit, and the plasticity number (or index)
• The liquid limit is the gravimetric moisture content at which the soil changes from being plastic and starts to behave as a viscous liquid. • The plastic limit is the gravimetric moisture content at which a soil changes from being ‘friable’ into being ‘plastic’. • The plasticity index is defined as the difference between the liquid and plastic limits. • Atterberg limits- The collective designation of five socalled limits of consistency of fine-grained soils, suggested by Albert Atterbrg, 1911-912, but with current usage usually retaining only the liquid limit, the plastic limit, and the plasticity number (or index)