Unit I
Distribution of wasteland and problem soils in India.
Their categorization (based on properties)
Chapter 1
Soil Quality and Soil Health
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Often soil health is considered independently without referring to interlinked soil functions and also based on soil tests for a few parameters. The physical condition of the soil and biological fertility is overlooked in soil health management which needs revisiting by soil users. Recognizing the importance of soil health in all dimensions, 2015 has been declared the International Year of Soils by the 68th UN General Assembly. It is estimated that out of the 328.8 m ha of the total geographical area in India, 173.65 m ha are degraded, producing less than 20% of its potential yield (Govt. of India, 1990).
Healthy soils provide us with a range of ecosystem services such as resisting erosion, receiving and storing water, retaining nutrients and acting as an environmental buffer in the landscapes. Soils have undergone unabated degradation at an alarming rate by wind and water erosion, desertification and salinization resulting from misuse and improper farming practices.
Soil quality, an antonym for soil degradation, has deteriorated due to natural and anthropogenic activities, particularly with the advent of intensive management practices.
Soil Functions
Five soil functions as enunciated by Karlen et al. (1997) are:
Sustaining biological activity, diversity and productivity
Regulating and partitioning water and solute flow
Filtering, buffering, degrading, immobilizing and detoxifying organic and inorganic materials, including industrial and municipal by-products and atmospheric decomposition
Storing and cycling nutrients and other elements within the earth's biosphere
Providing support to socio-economic structures and protection for archaeological treasures associated with human habitation.
Thus, soil acts to supply nutrients and offer favourable Physico-chemical conditions to plant growth, promote and sustain crop production, provide habitat to soil organisms, ameliorate environmental pollution, resist degradation and maintain or improve human and animal health.
Distribution of Wasteland and problematic soil
Types of wasteland
Problematic soil
These are soils which are economical for Cultivation
The soils which possess characteristics that make them uneconomical for the cultivation of crops without adopting proper reclamation measures are known as problematic soil/problem soils.
Types of soil problems:-
1. Physical Problem Soil
2. Chemical Problem soil
3. Biological Problem soil
4. Nutritional Problem soil
1) Physical problem soil
soil surface crusting
subsoil hard pan
Shallow soils
high permeable soil
heavy clay soil
2) Chemical problem soil
Evapotranspiration exceeds rainfall
Accumulation cause salinity or alkalinity
Ions mainly involved - Na, K, Mg and Calcium chlorides, carbonates
3) Biological Problem soil
Biological factors - Plants, animals, microorganisms, and humans affect soil formation. Animals and microorganisms mix soils and form burrows and pores. Plant roots open channels in the soils.