Welcome To UnderStand UPSC

Correct Answer: (a) 1 only
Explanation:
Statement 1: Black gram can be cultivated as both kharif and rabi crop.
Correct

• Black gram (Vigna mungo) is adaptable to both kharif (monsoon) and rabi (winter) seasons.
• In kharif, it is sown with monsoon onset (June–July), in rabi, it is grown as a post-rainy season crop, especially in rice fallows (October–November).

• Statement 2: Green-gram alone accounts for nearly half of pulse production.
  Incorrect
  • Chickpea (gram) dominates Indian pulse production (~48%), followed by pigeon pea (17%).
  • Green gram (moong) contributes only 8–9% of total pulse production.
• Statement 3: Production of kharif pulses increased, while rabi pulses decreased.
  Incorrect
  • Rabi pulses (e.g., chickpea) have increased significantly due to government schemes like the National Food Security Mission.
  • Kharif pulses (e.g., tur, urad) face stagnation due to shifting cultivation patterns and lower profitability.

Correct Answer: (a) Cotton

Explanation:

The described crop matches cotton due to the following characteristics:

1. Subtropical Nature: Thrives in warm climates, frost damages the crop.
2. Frost-Free Days: Requires ≥210 frost-free days (cotton’s growing season aligns with this).
3. Rainfall: Needs 50–100 cm rainfall (cotton grows in moderate rainfall zones or with irrigation).
4. Soil: Prefers light, well-drained soil (e.g., black cotton soil) that retains moisture.

Why Other Options Are Incorrect:

• Jute: Requires heavy rainfall (150–200 cm) and humid conditions, unsuitable for the given rainfall range.
• Sugarcane: Needs higher rainfall (75–150 cm) and richer soils, not light/well-drained.

Tea: Grows in high-rainfall (150–200 cm) hilly regions with acidic soil, not subtropical plains.

Correct Answer: (d) Neither 1 nor 2

Explanation:

Statement 1: Solar power can be used for running surface pumps and not for submersible pumps.

Incorrect

• Solar power can operate both surface and submersible pumps.
  • Surface pumps: Extract water from shallow sources (e.g., ponds, rivers).
  • Submersible pumps: Lift water from deep borewells (up to 100+ meters) and are powered by solar panels via inverters or DC motors.

Statement 2: Solar power can be used for running centrifugal pumps and not the ones with piston.

Incorrect

• Solar power supports both centrifugal and piston pumps:
  • Centrifugal pumps: Common for high-flow, low-lift applications (e.g., irrigation).
  • Piston/reciprocating pumps: Suitable for high-lift, low-flow needs (e.g., deep wells).

Correct Answer: (c) 1 and 4 only

Explanation:

Statement 1: A substantial saving in seed material is made when ‘bud chip settlings’ are raised in a nursery and transplanted in the main field.

Correct

• Bud chip technology reduces seed material requirements by up to 80% compared to conventional methods.
• Nursery-raised settlings ensure healthier plants and better field establishment.

Statement 2: Germination percentage is better with single-budded setts.

Incorrect

• Multi-budded setts have higher germination due to greater nutrient reserves. Single-budded setts lack sufficient energy for reliable sprouting.

Statement 3: Single-budded setts survive better in bad weather.

Incorrect

• Larger setts (with multiple buds) survive better in adverse conditions due to stored moisture and nutrients.

Statement 4: Sugarcane can be cultivated using tissue culture settlings.

Correct

• Tissue culture produces disease-free, uniform settlings for transplantation, enhancing crop quality.

Correct Answer: (c) 1, 3 and 4 only

Fertigation is a farming technique where fertilizers are dissolved in water and applied to crops through an irrigation system, like drip irrigation. 

1. Controlling the alkalinity of irrigation water is possible

Correct

• Fertigation allows precise adjustment of irrigation water pH using additives like urea phosphate or acids.
• This mitigates soil alkalinity, improves nutrient solubility, and prevents clogging in drip systems.
• Example: Urea phosphate releases H⁺ ions, lowering pH and enhancing nutrient uptake in alkaline soils.

2. Efficient application of Rock Phosphate and all other phosphatic fertilizers is possible

Incorrect

• Rock Phosphate is insoluble in water and cannot be applied via fertigation.
• Fertigation requires water-soluble fertilizers (e.g., urea, potassium nitrate).
• Phosphatic fertilizers like DAP or MAP are used instead of Rock Phosphate in fertigation.

Correct

• Nutrients are delivered directly to the root zone via drip irrigation, enhancing absorption.
• Fertilizer use efficiency increases to 80–90% compared to 30–40% in traditional methods.
• Ensures optimal growth and higher yields (25–50% increase).

4. Reduction in the leaching of chemical nutrients is possible

Correct

• Precise application minimizes excess fertilizer, reducing nutrient runoff and groundwater contamination.
• Targeted delivery prevents waterlogging and leaching, especially in heavy rainfall areas.