Badland topography in Chambal is due to:

I. arid climate
II. improper agri practices
III. ravines
IV. None of the above

Consider the following statements:

I. Humus is not a mineral.
II. Humus helps to retain moisture in the soil.
III. It helps the plant in absorbing materials from the soil for building its body.
IV. A soil looks dark on account of the presence of humus.

Which of the statements given above is/are correct?

In India, the problem of soil erosion is associated with which of the following? 

1. Terrace cultivation

2. Deforestation

3. Tropical climate 

Select the correct answer using the codes given below

In the following question, there are two statements one as labelled Assertion (A) and other one as Reason (R). Select the correct answer using the codes given below.

Assertion (A:) The desert soils of India are poor in mineral nutrients and hence infertile.
Reason (R): The dearth of rainfall and humus does not allow good soil formation.

Saline and Alkaline soils are characterised by which of the following features?

I. They are found in drought-prone areas.
II. They can be reclaimed by adding gypsum.
III. They are sandy-loams.

Select the correct answer using the codes given below.