Ans : A 

Exp: 

Option A is correct : Layers of soil are called horizons. ‘Horizon A’ is the topmost zone, where organic materials have got incorporated with the mineral matter, nutrients and water, which are necessary for the growth of plants. 

‘Horizon B’ is a transition zone between the ‘Horizon A’ and ‘Horizon C’, and contains matter derived from below as well as from above.

Fig: Layers of Soil

Ans: C

Exp:

Option c is correct : Grasses have deep roots that help to hold the soil in place.  They also help to prevent wind erosion by breaking up the wind.

For instance : Bermuda Grass Its dense growth habit and deep roots make it an effective option for controlling erosion on slopes and in other areas prone to erosion.

Buffalo Grass –  Its low-growing, fine-leaved habit helps to bind soil particles together and stabilise slopes.

Nepalese Browntop- Its deep roots and strong rhizomes make it an effective option for erosion control and slope stabilisation.

Ans: B

Exp:

Soil erosion is a gradual process that occurs when the impact of water or wind detaches and removes soil particles, causing the soil to deteriorate.

Statement 1 is correct: Soil erosion is responsible for the removal of productive nutrients from the soils and causes ecological imbalances. Some of the consequences of soil erosion : 

• Loss of fertile topsoil from the top layer leads to the gradual loss of soil fertility and agricultural productivity.

• Loss of essential nutrients from the soil through leaching and water-logging.
• Lowering of the underground water table and decrease in soil moisture.

Statement 2 is incorrect: Siltation refers to increased concentration of suspended sediments and to the increased accumulation of fine sediments on bottoms where they are undesirable. Siltation is most often caused by soil erosion or sediment spill. So, silting and not de-siltation of rivers and canal beds is a consequence of soil erosion. 

Statement 3 is correct : Some adverse consequences of soil erosion are: 

• Increase in the frequency of droughts and floods.

• Recurrence of landslides
• Adverse effect on the economy which retards cultural development
• Burden on the exchequer to reclaim the badlands.

Ans : B

Exp:  

Black soils covers most of the Deccan Plateau which includes parts of Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh and some parts of Tamil Nadu.

Statement 1 is correct : These soils are also known as the ‘Regur Soil’ or the ‘Black Cotton Soil’. The black soils are generally clayey, deep and impermeable. 

Statement 2 is correct : They swell and become sticky when wet and shrink when dried. 

So, during the dry season, these soil develop wide cracks. 

Statement 3 is correct :  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 in phosphorous, nitrogen and organic matter. The colour of the soil ranges from deep black to grey.

Ans: C

Exp: 

Both statement 1 and 2 are correct

Contour Bunding:  It consists of building earthen embankments across the slope of the land, following the contour as closely as possible. A series of such bunds divide the area into strips and act as barriers to the flow of water, thus reducing the amount and velocity of the runoff. They help trap sediment and reduces soil erosion.

 Fig: Contour Bunding

Peripheral bunds:

Bunds are also constructed along field boundaries without reference to contour. These bunds are called peripheral bunds. They serve as fences and give protection from water and wind erosion.