Consider the following statements :1. Self-ploughing is a phenomenon a...
Black soils are formed due to the weathering and denudation of volcanic rocks, that is, the solidification of lava after volcanic eruptions. Black soil covers most of the Deccan Plateau, including parts of Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh and some parts of Tamil Nadu.
The black soil is very deep in the upper reaches of the Godavari and the Krishna and the north western part of the Deccan Plateau. These soils are also known as the ‘Regur Soil’ or the ‘Black Cotton Soil.’ The black soils are generally clayey, deep and impermeable.
They swell and become sticky when wet and shrink when dried. So, during the dry season, these soils develop wide cracks. Thus, there occurs a kind of ‘self-ploughing.’ Because of this character of slow absorption and loss of moisture, the black soil retains the moisture for a very long time, which helps the crops, especially; the rain-fed ones, to sustain even during the dry season.
Chemically, the black soils are rich in lime, iron, magnesia and alumina. They also contain potash. But they lack phosphorous, nitrogen and organic matter. The colour of the soil ranges from deep black to grey.
So, Option (a) is correct.