Introduction
Soil serves as a natural medium for the growth of plants. Soils of one location may vary from that of others depending on the genesis and environmental factors. Soil contains four major components, mineral material, organic matter, water and air, the proportions of which vary with respect to time, site and depth. The soils of India are derived from a wide variety of minerals. They differ physically, chemically and biologically. Their distribution does not follow any regular pattern. The soils of India are broadly divided into five major groups: - Alluvial soil (Entisol, Inceptisol, Alfisol), black soil (Vertisol, Inceptisol, Entisol), red soils (Alfisol, Inceptisol, Ultisol), laterite soil (Alfisol, Ultisol, Oxisol), and desert soil (Entisol, Aridisol).
Black Soil
The typical soil derived from the Deccan trap is the regur or black cotton soil. These soils vary in depth from shallow to deep. It is common in Maharashtra, western parts of Madhya Pradesh, parts of Andhra Pradesh, parts of Gujarat, and some parts of Tamil Nadu. Many black soil areas have a high degree of fertility. They are darker, deeper and richer and are constantly enriched by the additions washed down from the hills. In the uplands, these are poor, light-coloured and thin.
Black soils are highly argillaceous, very fine-grained and dark and contain a high proportion of calcium and magnesium carbonates. They are poor in P2O5, N and organic matter. These soils contain abundant iron and fairly high quantities of lime, magnesia and alumina.
Problem
These soils have high plasticity and stickiness. They are very tenacious and exceedingly sticking when wet. Owing to considerable contraction on drying large and deep cracks are formed. Thus cracking on drying and water logging are the major problem of black soils alongwith low in nitrogen, organic matter and phosphorus.
Management
Successful farming concerns the appropriate management of soils, plants and the environment in such a way that a maximum return can be obtain not only in a season or year but also over centuries. The most important consideration in soil management is the correct application of the relationship among the soil, the environment and the crop to be grown. Soil management varies according to the soils and their situation in the land the climatic conditions, biotic influences and crops to be grown. For black soil following measures are taken:
Good soil tilth
It is the first feature of good soil management which means suitable physical condition of the soil and implies satisfactory regulation of soil moisture and air, also it minimizes erosion hazards. These soils, being self ploughed need not to plough every year. Ploughing once in 3 years.
Proper drainage
Due to poor drainage of excess water, water logging conditions occur in these soils, hence proper drainage should be provided to minimize the damage cause due to excess water.
Irrigation frequency
In deep clay soils a huge quantity of water is lost in filling up cracks before it reaches saturation level and in flowing further to cover the entire area; if the clay soils are not irrigated immediately after development of small cracks these cracks deepen on widen resulting in tearing of roots on and accelerate, evaporation from the manifold area exposed due to vertical cracking. Under such situation the frequent application of light irrigation may be needed.
Addition of organic matter
Due to low in organic manures and nitrogen, the productive capacity of the soil should be improved and maintained by providing adequate organic manures and plant nutrients through fertilisers and by including legumes in the rotation and the use of biofertilisers.
Ag.
Technologies
(Soil Magt.)
