UPSC Mains 2016 GS3 Q8 — Agricultural Science
What is allelopathy? Discuss its role in major cropping systems of irrigated agriculture. (Answer in not more than 200 words)
Question Decoded — examiner's intent
- Directive verbs
- What isDiscuss
- Scope keywords
- allelopathyrolemajor cropping systemsirrigated agriculture
- Implicit sub-parts
- Scientific mechanism of biochemical interaction between plants (stimulatory vs inhibitory).
- Impact on specific irrigated rotations like Rice-Wheat or Sugarcane.
- Dual nature of allelopathy as both a constraint (weed pressure, soil sickness) and a solution (bio-herbicides, companion cropping).
- Management strategies for allelopathic effects in high-input irrigation zones.
- Common pitfalls
- Confining the definition only to negative effects; ignoring that allelochemicals can also promote growth.
- Failing to specifically address the 'irrigated agriculture' context, leading to generic ecological answers.
- Confusing allelopathy with resource competition (light, water, nutrients).
- Missing concrete examples of crops like Eucalyptus, Black Walnut, or Parthenium which are crucial for GS3 technical marks.
- Dimensions required
- Biological/EcologicalAgronomic/TechnicalEconomic/Farmer IncomeEnvironmental Sustainability
- Marks allocation hint
Allocate 25-30 words for a precise biochemical definition. Spend 120-130 words discussing the role in irrigated systems, split equally between challenges (autotoxicity, weed growth) and opportunities (weed management, natural pesticides). Use the final 40 words for a forward-looking conclusion on sustainable weed management.
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