Which substance is commonly added to reclaim saline and alkaline soil?
- A.Gypsum
- B.Urea
- C.Common salt
- D.Lime
Correct answer
Explanation
The correct answer is A, gypsum. Gypsum, that is calcium sulphate, supplies calcium that replaces the sodium held on the soil particles, and once the sodium is set free it can be washed out of the field by irrigation and drainage, restoring structure to land that had become hard and impermeable. Option B is wrong because urea is a nitrogen fertiliser that feeds the crop but does nothing about the excess sodium, and heavy use of it can even worsen the reaction of the soil. Option C is wrong because common salt is itself the problem in such land, since saline soil already carries too much sodium chloride and other salts. Option D is wrong because lime is used the other way round, to correct soil that is too acidic, for example the leached laterite and hill soils of the high-rainfall belt.
Read the full article: Soils of India: Types, Distribution, Erosion and PYQs
Practice Questions
View allThe deltas of the Mahanadi and the Godavari are rich in ______ soil.
- A.black
- B.arid
- C.forest
- D.alluvial
Show answer
A delta is built out of silt that a river carries down and drops where it meets the sea, so deltaic land is alluvial by definition, and the eastern coastal deltas of the Mahanadi, Godavari, Krishna and Kaveri are among the most fertile rice tracts of the country.
Read the full explanation →Which of the following statements about black soil is INCORRECT?
- A.It is found along the Deccan trap.
- B.It is rich in phosphoric content.
- C.It has a good capacity to hold moisture.
- D.It develops deep cracks during hot weather.
Show answer
What it is rich in is calcium carbonate, magnesium, potash and lime, and remembering that short list is the safest way to answer any statement question on this soil.
Read the full explanation →Which of the following is the LEAST visible form of land erosion?
- A.Gully erosion
- B.Landslides
- C.Sheet erosion
- D.Ravine formation
Show answer
In sheet erosion water spreads over a wide slope and carries away a thin, even film of topsoil, so nothing obvious is left behind to see, and the loss is noticed only years later as falling yields.
Read the full explanation →Which of the following is NOT a method of soil conservation?
- A.Intercropping
- B.Mulching
- C.Contour Ploughing
- D.Weathering
Show answer
Weathering is the natural breaking down of rock by temperature, water, wind and living things, and it is the process that makes soil in the first place; it is not a technique that a farmer applies to save soil, so it cannot be a conservation method.
Read the full explanation →What makes the soil fertile?
- A.Overabundance of acidic materials in the soil
- B.The right mix of minerals and inorganic matter
- C.The right mix of minerals and organic matter
- D.High levels of salt in the soil
Show answer
Fertility needs mineral nutrients such as nitrogen, phosphorus and potassium from the weathered rock, and organic matter, that is humus from decayed plants and animals, which holds water, feeds soil organisms and releases nutrients slowly.
Read the full explanation →