CDS (II) 2021 General Knowledge · Question 67 of 120

Correct — C, Himachal Pradesh. Both practices in the stem are answers to the same problem — water running downhill fast enough to carry the topsoil with it — and that problem exists on slopes. Ploughing along the contour instead of up and down it turns every furrow into a small barrier across the line of flow, and a contour bund does the same job with a raised earth embankment built along the contour. Of the four States offered, only Himachal Pradesh is hill country; NCERT makes the link explicit when it says the western and central Himalaya have well-developed terrace farming, and the western Himalaya is where Himachal Pradesh sits. Punjab and Haryana are flat alluvial plains where the working problems are waterlogging, salinity and over-irrigation, and Rajasthan's western districts lose soil to wind rather than to running water.

• (a)Punjab — Punjab is level alluvial plain. Its recognised land-degradation problem is over-irrigation leading to waterlogging and salinity, which contour work does nothing about.
• (b)Haryana — Haryana is likewise plains country. Where its land does degrade, the causes are salinity and gullying near seasonal streams rather than sheet wash down a hillside.
• (d)Rajasthan — Rajasthan's dominant erosion agent in the west is wind, and the standard answers there are shelter belts, sand fences and stabilising the dunes with vegetation, not bunds along a contour.

Soil conservation on slopes works by shortening the distance water is allowed to run before something interrupts it. Contour ploughing lays the furrows along the contour so each one holds water back; contour bunding raises small embankments along the same lines; terracing cuts the slope into a staircase of level steps; strip cropping alternates bands of crop and grass so the grass breaks the flow. On flat land the toolkit is different — shelter belts and sand fences against wind, drainage and gypsum against waterlogging and alkalinity.

The scenario framing is decoration; the question is asking which of four States has slopes. It is worth being precise about why the answer is not simply 'wherever there are hills': contour bunding is used on gentle to moderate slopes, and once the gradient steepens, terracing takes over. UPSC has asked this same distinction in an unusually blunt way, offering only flat or non-slope settings and requiring the candidate to reject all of them.

• Ploughing along the contour slows water moving down a slope and is called contour ploughing.
• A contour bund is an earth embankment built along the contour to hold back runoff on gentle to moderate slopes.
• Terrace cultivation cuts a slope into level steps and is well developed in the western and central Himalaya.
• Strip cropping leaves bands of grass between crop strips to break the force of wind and water.
• Shelter belts are rows of trees planted to reduce wind erosion, the characteristic hazard of arid western Rajasthan.

• Reading contour bunding as a flood-control measure for river plains.
• Assuming any conservation practice can be used on any terrain; the practice named tells you the terrain.
• Overlooking that Himachal Pradesh, not Uttarakhand, is the hill State on this particular option list.

As a practice-to-terrain match, as a practice-to-State identification, or as a statements item on soil conservation measures.

• practice — not a real PYQ

  Shelter belts are used mainly to control which one of the following?

  • (a)Sheet erosion by running water
  • (b)Wind erosion
  • (c)Gully formation
  • (d)Soil salinity

  Answer(b) Wind erosion — rows of trees planted across the prevailing wind reduce its speed and its power to lift soil.

• practice — not a real PYQ

  Terrace cultivation is best described as

  • (a)growing two crops on the same field in one year
  • (b)cutting a slope into a series of level steps for cultivation
  • (c)leaving alternate strips of land fallow
  • (d)growing crops without ploughing the soil

  Answer(b) — the staircase of level steps stops water gathering speed down the slope.