Which of the following statements with reference to saline soil in India is/are correct? 1. They are rich in nitrogen. 2. They occur in arid and semi-arid regions, and in waterlogged and swampy areas. Select the answer using the code given below:
- (a)1 only
- (b)2 only
- (c)Both 1 and 2
- (d)Neither 1 nor 2
Correct — B, 2 only. Statement 2 is exactly right, and its two halves are not as contradictory as they look. Saline soils build up wherever salts are brought to the root zone and not flushed away: in arid and semi-arid country, evaporation pulls salt-laden water up to the surface and leaves the salt behind as the water goes; in waterlogged and swampy tracts the water table stands so high that drainage cannot remove the salts and the same accumulation happens for the opposite reason. Both conditions therefore produce the same soil. Statement 1 is the false half. Saline or Usara soils carry a larger proportion of sodium, potassium and magnesium and are correspondingly infertile — and they are specifically deficient in nitrogen and calcium. Nitrogen comes into soil chiefly through organic matter and biological fixation, and a soil salty enough to suppress plant growth has very little of either.
- (a)1 only — Reverses the truth on both counts. Saline soils lack nitrogen and calcium, and the occurrence described in statement 2 is accurate.
- (c)Both 1 and 2 — Statement 2 is right, but a soil that will not support vegetative growth cannot be rich in nitrogen; the salts present are sodium, potassium and magnesium.
- (d)Neither 1 nor 2 — Rejects the accurate statement. Both arid and semi-arid tracts and waterlogged, swampy areas are standard settings for saline soils.
Saline soils, called Usara in the older Indian literature, are one of the recognised soil groups of India. They are defined by an excess of soluble salts rather than by their parent rock. Structurally they run from sandy to loamy. In India they are most widespread in western Gujarat, in the deltas of the eastern coast and in the Sunderban country of West Bengal; in the Rann of Kachchh the south-west monsoon carries in salt particles that are deposited as a crust, while sea-water intrusion promotes salinity in the deltas.
Two things trip candidates up. The first is the pairing in statement 2 — arid land and swamp seem like opposites, so the statement reads as if it must be wrong, when in fact both are classic salinity settings and for related reasons: one has too little water to flush salts down, the other cannot drain them away. The second is the temptation to attach 'rich in' to whichever nutrient the option names. Fix the composition instead: sodium, potassium and magnesium are in excess, nitrogen and calcium are deficient. A useful cross-check is that irrigation itself creates saline soil where drainage is poor, which is why canal-irrigated tracts of Punjab, Haryana and western Uttar Pradesh have suffered salinisation.
- Saline soils are also known as Usara soils and contain a larger proportion of sodium, potassium and magnesium, which makes them infertile.
- They occur in arid and semi-arid regions and in waterlogged and swampy areas, and their structure ranges from sandy to loamy.
- They lack nitrogen and calcium.
- They are most widespread in western Gujarat, the deltas of the eastern coast and the Sunderban areas of West Bengal.
- In the Rann of Kachchh the south-west monsoon brings in salt particles that are deposited as a crust, and sea-water intrusion promotes salinity in the deltas.
- Rejecting statement 2 because arid land and swamp seem incompatible; both produce salinity, by opposite routes.
- Assuming a soil holding a lot of salts must be nutrient-rich; the salts are sodium, potassium and magnesium, and nitrogen and calcium are short.
- Confusing saline soils with peaty soils, which are the organic-rich, high-humus soils of heavy-rainfall areas.
As a two-statement item on the composition or occurrence of a named soil type, or as a description-to-soil identification with three clues.
Identify the type of soil on the basis of the given characteristics : 1. They are rich in lime, iron, magnesia and alumina. 2. They are generally clayey, deep and impermeable. 3. They are mainly found in Maharashtra, Madhya Pradesh and Gujarat. Select the correct answer from the given alternatives :
- (a) Laterite soil
- (b) Red and yellow soil
- (c) Saline soil
- (d) Black soil
Answer(d) Black soil
The same body of soil knowledge, tested by description rather than by statement, and saline soil appears there as a distractor. Both items are decided by the nutrient profile — lime, iron, magnesia and alumina for the black soil, sodium and magnesium with a nitrogen and calcium deficit for the saline one.
- practice — not a real PYQ
Saline soils of India are deficient in which one of the following pairs of nutrients?
- (a)Sodium and potassium
- (b)Nitrogen and calcium
- (c)Magnesium and sodium
- (d)Potassium and magnesium
Answer(b) Nitrogen and calcium — sodium, potassium and magnesium are the elements present in excess.
- practice — not a real PYQ
Saline soils in India are most widespread in which one of the following groups of areas?
- (a)The Chota Nagpur plateau and the Aravallis
- (b)Western Gujarat, the eastern coastal deltas and the Sunderbans
- (c)The Shillong plateau and the Nilgiris
- (d)The Malwa plateau and Bundelkhand
Answer(b) Western Gujarat, the eastern coastal deltas and the Sunderbans — evaporation in the Rann and sea-water intrusion in the deltas are the two main causes.