Agriculture 2025 Paper I 50 marks Enumerate

Q6

(a) Enumerate the harmful effects of herbicide residues in soil. Discuss the remedial measures to overcome the above problem. (20 marks) (b) Give a lucid account on the factors influencing soil formation. (20 marks) (c) Present a brief note on the types of mulches and their role in soil moisture conservation. (10 marks)

हिंदी में प्रश्न पढ़ें

(a) मृदा में शाकनाशियों के अवशेष के हानिकारक प्रभावों का उल्लेख कीजिए। उक्त समस्या के निवारण हेतु उपचारात्मक उपायों की विवेचना कीजिए। (20 अंक) (b) मृदा-निर्माण को प्रभावित करने वाले कारकों का स्पष्ट वर्णन कीजिए। (20 अंक) (c) पलवार के प्रकारों एवं मृदा नमी संरक्षण में उनकी भूमिका पर एक संक्षिप्‍ट टिप्पणी प्रस्तुत कीजिए। (10 अंक)

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Directive word: Enumerate

This question asks you to enumerate. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.

See our UPSC directive words guide for a full breakdown of how to respond to each command word.

How this answer will be evaluated

Approach

The directive 'enumerate' for part (a) demands systematic listing with elaboration, while 'lucid account' for (b) and 'brief note' for (c) require clarity and conciseness respectively. Allocate approximately 40% of time/words to part (a) given its 20 marks and dual demand (effects + remedies), 35% to part (b) for comprehensive factor analysis, and 25% to part (c) for concise mulch classification. Structure with clear sub-headings for each part, ensuring part (a) balances enumeration with discussion of remedial measures, part (b) integrates all five soil-forming factors with their interactions, and part (c) prioritizes moisture conservation mechanisms over exhaustive mulch types.

Key points expected

  • Part (a): Harmful effects of herbicide residues — soil microbial toxicity (nitrification inhibition, reduction in beneficial bacteria/fungi), phytotoxicity to succeeding crops (carryover injury, residue accumulation in food chain), soil physicochemical degradation (organic matter depletion, pH alteration), groundwater contamination and non-target organism toxicity
  • Part (a): Remedial measures — microbial degradation (bioaugmentation with Pseudomonas, Bacillus), phytoremediation (hyperaccumulator plants), adsorption techniques (activated carbon, biochar), crop rotation with tolerant species, and integrated weed management (IWM) reducing chemical dependency
  • Part (b): Five soil-forming factors — detailed explanation of parent material (igneous/sedimentary/metamorphic influence), climate (temperature and precipitation as pedogenic drivers), topography (drainage, erosion, aspect effects), organisms (vegetation type, soil fauna, microbial activity), and time (degree of profile development)
  • Part (b): Factor interactions — exemplified through laterite formation (climate + parent material), podzolization (climate + vegetation + time), or alluvial soil development (topography + parent material + time)
  • Part (c): Mulch types — organic mulches (straw, crop residues, green manure, compost) versus inorganic mulches (plastic mulches: black, transparent, biodegradable; pebble/gravel mulches; reflective mulches)
  • Part (c): Moisture conservation mechanisms — evaporation suppression (physical barrier), temperature moderation (reducing evaporative demand), infiltration enhancement, weed suppression eliminating competition, and specific examples like plasticulture in water-scarce regions

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Demonstrates precise scientific understanding across all parts: for (a) correctly identifies glyphosate/ atrazine persistence, microbial C:N ratio disruption, and biomagnification pathways; for (b) accurately distinguishes between passive (parent material) and active (climate, organisms) factors with correct pedological terminology (pedon, solum, horizon differentiation); for (c) correctly differentiates between evaporation suppression and transpiration reduction mechanisms in mulchingCovers basic concepts with minor errors: lists herbicide effects without specifying microbial pathways, describes soil factors superficially without their interactions, or conflates mulch types without clear moisture conservation mechanismsSignificant conceptual errors: confuses herbicide with pesticide toxicity mechanisms, omits key soil-forming factors or misrepresents their roles (e.g., treating topography as parent material), or describes mulches without linking to moisture conservation
Quantitative reasoning15%7.5Integrates relevant quantitative data appropriately: for (a) cites herbicide half-life periods (atrazine 60-100 days, glyphosate 47 days), residue tolerance limits (MRLs in ppb), or degradation rates; for (b) references soil formation rates (1 cm/100-1000 years), precipitation thresholds for pedogenesis; for (c) provides water use efficiency improvements (25-40% savings), evaporation reduction percentagesMentions quantitative terms vaguely (e.g., 'long persistence,' 'slow formation') without specific figures, or provides incorrect/unsupported numerical claimsNo quantitative dimension; entirely qualitative treatment where numerical substantiation is expected, or fabricates implausible statistics
Indian context examples20%10Rich India-specific illustrations: for (a) cites Punjab-Haryana paddy-wheat belt herbicide residue crisis (paraquat, butachlor persistence), ICAR studies on residue impact; for (b) exemplifies with Indian soil orders — black cotton soil (climate + parent material), red and yellow soils (laterization in Western Ghats), alluvial Indo-Gangetic plains; for (c) references plasticulture expansion in Gujarat, Karnataka; straw mulch in conservation agriculture (CA) in Haryana; PMKSY mulching subsidiesGeneric or token Indian references: mentions 'Indian agriculture' without specificity, or cites common examples without connecting to regional soil/agronomic contextsEntirely foreign examples (Midwest US herbicide use, podzols of Russia) or no contextualization to Indian agricultural conditions and soil diversity
Diagram / process20%10Includes well-executed diagrams: for (a) schematic of herbicide degradation pathways (photochemical, microbial, chemical) or residue movement in soil profile; for (b) CLORPT model diagram showing factor interactions, or soil profile development sequence; for (c) cross-section of mulched soil showing moisture gradient, temperature regime, and water movement; all diagrams properly labeled and integrated with textMentions diagrams but provides poorly executed or irrelevant sketches, or describes processes verbally where visual representation would strengthen answerNo diagrams despite clear scope; or diagrams entirely missing, poorly labeled, or conceptually wrong (e.g., showing herbicide uptake by roots as 'remedial measure')
Policy / extension angle20%10Demonstrates policy literacy: for (a) references Insecticides Act 1968, CIBRC herbicide bans/restrictions, FSSAI MRL regulations, IPM/INM promotion under NAPCC; for (b) links to soil health card scheme, land use planning, watershed management programs; for (c) connects to PMKSY (More Crop Per Drop), Sub-Mission on Agricultural Mechanization (mulching equipment), organic farming promotion under PKVY; suggests extension strategies for farmer adoptionMentions policies superficially without specific schemes or connects generic 'government should' recommendations without naming actual programsNo policy dimension; treats topics as purely technical without governance, regulatory, or extension implications relevant to Indian agriculture

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