SAC 507 : LECTURE 4 OUTLINE
Acid soils, pools of soil acidity and buffering in soils
What is an acid soil?Active acidity , exchangeable acidity , non- exchangeable acidity, potential acidity and total acidity
General relationship between soil pH and the cations held by soil colloids
Buffering of pH in soils:
Definition of buffering capacity
Factors : Equilibrium between exchangeable acidity and active acidity, synthesis of organic acids during decomposition of organic matter, protonation and deprotonation of the functional groups.
How do soils differ in their capacity to buffer and reasons for buffering in different pH zones.
Is buffering capacity a boon from the point of view of crop production ?
Classroom Video
By Dr. T S VAGEESH and Dr. S B SALIMATH
SAC-507 Class 4.1 : Acid soils, pools of soil acidity and buffering in soils
SAC-507 Class 4.2 : General relationship between soil pH and the cations held by soil colloids.
SAC 507 : LECTURE 5 OUTLINE
Ionic product of water, Genesis, distribution of acid soils in India
- pH and Ionic product of water
- Genesis of acid soils and the factors behind acid soils formation
- Distribution of acid soils in India
Classroom Video
SAC-507 Class 5 : Ionic product of water, Genesis, distribution of acid soils
SAC 507 : LECTURE 6 OUTLINE
Classification of acid soils of India and problems of acid soils
- Classification of acid soils of India
- Major taxonomical orders to which acid soils of India belong
- Problems of acid soils and their remedies
- Al toxicity in plants
- Mn, H and Fe toxicity in plants
Classroom Video
SAC-507 Class 6 : Classification of acid soils of India and problems of acid soils.
SAC-507 Class 7 : Salt affected Soils
SAC-507 Class 8.1
SAC-507 Class 8.2
SAC-507 Class 9 Problems of acid soils (…contd)
- Reduced nutrient availability to crops
- Reduced microbial activity in the soil
- Reduced mobility of organic molecules like herbicides
Management of acid soils
- Selection of crops and varieties
Tolerant, medium tolerant and sensitive crops to acidity
Liming of acid soils
Physical, chemical and biological changes in soil upon application of lime
Lime requirement of acid soils And its measurement
Classroom Video
SAC-507 Class 9.1
SAC-507 Class 9.2
SAC-507 Class 10
LECTURE 10 OUTLINE
Liming of acid soils
Measurement of lime requirement
- Exchangeable Al method
- Buffer pH methods
- Schoemaker method or SMP method
- Mehlich method
- 45 per cent Ca saturation method
- Liming factor
Guidelines for effective utilization of liming materials
- Method and time of lime application
- Frequency of liming
- Depth of lime application
- Quantity of lime / overliming
Classroom Video
SAC-507 Class 11 : Sodic Soils and the process of Sodification
SAC 507 : LECTURE 12 OUTLINE
pH measurement as an index of soil acidity and lime potential
Measurement of soil pH and its drawbacks
- pH measurement with water
- pH measurement with CaCl2
- pH measurement with KCl
Lime potential as a measure of soil acidity
- Derivation of lime potential LP = pH – ½ pCa
- Measurement of lime potential in the lab and its advantages over pH
Agricultural liming materials
- Oxides of lime
- Hydroxides of lime
- Carbonates of lime
Calcites, dolomites, industrial byproducts
- Comparison of liming materials
SAC-507 Class 12 :
SAC-507 Class 13 :Remote Sensing
SAC 507 : LECTURE 14 OUTLINE
Agricultural liming materials
- Fineness of liming materials
Acid sulfate soils
- Acid sulfate materials in coastal sediments
and chemical changes upon their oxidation
- ‘Kari’ soils and their management
Problems of laterites/ lateritic soils and their management
- Laterites and lateritic soils, their formation and classification
- Differences in the characteristics of Laterites and lateritic soils
- Constraints of Laterites and lateritic soils
- Management of Laterites and lateritic soil
Lecture Video SAC-507 Class 14 :
Lecture Video SAC-507 Class 15 : Management of sodic soils - Physical and chemical amelioration methods.
Lecture Video SAC-507 Class 16: Quality of Irrigation water.
SAC 507 : LECTURE 17 OUTLINE
Problems of clay soils and their management
- Clay as a soil and its characteristics
- Problems of clay soil
- Plasticity, heavy soils
- Stickyness and dryness
- Air-water relationships in rhizosphere
- Slow permeability and drainage
- Swelling and shrinking
- Soil erosion through runoff water
- Compact sub-soil layer
- Management of clay soils
- Application of sand
- Application of gypsum
- Use of coir and coco peat
- Deep tillage and use of sub-soiler
- Drainage network
- compartmental bunding
- deep rooted crops
Physically degraded soils and their management
- soil degradation and degradation processes
Soil compaction and its management
***
