Chapter Overview

Agricultural science (कृषि विज्ञान) is part of the Applied Science section of Mains Paper IV (GS-II). Other chapters cover where crops grow (Geography: Agriculture) and how farming is financed and priced (Agriculture and the Economy). This chapter covers how crops grow and how they are fed and protected: crop physiology, the logic of cropping systems, seeds and breeding, soil nutrients and fertilisers, organic and natural farming, and pest management. For Chhattisgarh, the “Rice Bowl of India”, these topics come up in Mains answers, the Essay paper and the Interview.

What You’ll Learn

By the end of this chapter, you will be able to:

Explain C3, C4 and photoperiod responses and the scientific logic of rotation, intercropping, relay cropping (utera), SRI, DSR and conservation agriculture
Describe the seed chain and its tag colours, hybrids versus varieties, biofortification, GM crops and India’s genome-edited rice
List the 17 essential nutrients, the roles and deficiency symptoms of NPK and micronutrients, and how acid and sodic soils are corrected
Compare urea, DAP, SSP and MOP, and evaluate neem-coated urea, nano urea and the NPK imbalance
Classify manures and biofertilisers and explain Integrated Nutrient Management
Distinguish organic from natural farming and explain certification (NPOP, PGS-India, LAC) and the National Mission on Natural Farming
Apply IPM concepts (ETL, EIL, biocontrol, the 3R problem) and write balanced Mains answers with a Chhattisgarh angle

Prerequisites

Cropping Seasons and Farming Systems: kharif, rabi, zaid and types of farming
Soils and Natural Vegetation: Indian soil types
Agriculture and Irrigation in Chhattisgarh: the state’s crops, zones and schemes
Biology and Health: plant cells, photosynthesis and microbes

Learning Path

Follow the topics in this order:

graph TD
    A["1. Crop Science and Cropping Systems
C3/C4, rotation, SRI, DSR, utera"] --> B["2. Seed Technology
seed chain, hybrids, GM,
genome editing, biofortification"]
    B --> C["3. Soil Fertility, Fertilisers
and Manures
NPK, urea, biofertilisers, INM"]
    C --> D["4. Organic and Natural Farming
ZBNF, NPOP, PGS, NMNF"]
    D --> E["5. Pest Management and IPM
3Rs, biocontrol, ETL"]
    E --> F["Quick Revision
One-page sheet"]

Topics in This Chapter

#	Topic	What it covers
1	Crop Science and Cropping Systems	Crop classification, C3/C4/CAM, photoperiod, growth stages, rotation, intercropping and LER, legume nitrogen fixation, puddled rice, SRI, DSR, AWD, conservation agriculture, biasi and utera
2	Seed Technology and Crop Improvement	Varieties and hybrids, seed classes and tag colours, breeding methods, biofortification (Chhattisgarh Zinc Rice-1), Bt cotton, GM mustard, genome-edited rice, Seeds Act and PPV&FR Act
3	Soil Fertility, Fertilisers and Manures	17 essential elements, NPK roles and deficiencies, soil pH correction, fertiliser grades, nitrogen losses, neem-coated and nano urea, Soil Health Card, manures, biofertilisers, INM
4	Organic and Natural Farming	Organic vs natural farming, ZBNF’s four wheels, NPOP, PGS-India and Large Area Certification, PKVY, NMNF (2024), Sikkim and Dantewada, evaluation and the Sri Lanka lesson
5	Pest Management and IPM	Pest groups, rice pests of Chhattisgarh, control methods, biocontrol agents, pesticide classes and labels, the 3R problem, regulation, IPM with ETL and EIL, fall armyworm and locusts
—	Quick Revision	Every number, name and distinction from the chapter on one page

Where It Is Asked

Paper	What to expect
Mains P-IV (GS-II), Part 3: Applied and Behavioural Science	Short answers (e.g. “what are biofertilisers?”, “distinguish organic and natural farming”, “what is IPM?”, “C3 vs C4”) and longer analytical answers (soil health and NPK imbalance, GM and genome-edited crops, natural farming and food security, sustainable rice systems)
Mains P-II (Essay) and Interview	Sustainable agriculture, chemical-free farming, Chhattisgarh’s paddy economy and diversification

Exam focus

High-yield: C3 vs C4 crops; biofertilisers and their crops; fertiliser nutrient contents (urea 46% N, DAP 18-46, MOP 60% K₂O); NPK 4:2:1; neem-coated urea; organic vs natural farming; ETL vs EIL; the 3Rs; GEAC and genome-editing exemption.
Common mistakes: calling Azolla a cyanobacterium; mixing up Trichoderma (fungus) and Trichogramma (wasp); saying IPM bans pesticides; saying NPOP is run by the Agriculture Ministry.
Chhattisgarh angle for Mains: biasi and utera; IGKV Raipur’s rice germplasm and Chhattisgarh Zinc Rice-1; acidic red-yellow soils and khaira; Godhan Nyay vermicompost; Dantewada’s Large Area Certification; rice gall midge (gangai) and NIBSM Raipur.

Quick Reference: The Chapter at a Glance

Theme	Key facts
Photosynthesis types	C3: rice, wheat, pulses · C4: maize, sugarcane, sorghum, millets · CAM: pineapple
Rice systems	SRI (Madagascar, 1980s), DSR, AWD; flooded paddy emits methane
Seed chain	Breeder (golden yellow) → foundation (white) → certified (azure blue)
GM and genome editing	Bt cotton 2002; Bt brinjal moratorium 2010; GM mustard release approval 2022; SDN-1/2 exemption 2022; genome-edited rice May 2025
Seed laws	Seeds Act 1966; PPV&FR Act 2001; draft Seeds Bill 2025 (not enacted as of 2026)
Fertilisers	Urea 46% N; DAP 18-46; SSP 16% P₂O₅; MOP 60% K₂O (wholly imported)
Soil policy	NBS 2010; Soil Health Card 2015; neem-coated urea 2015; nano urea 2021; PM-PRANAM 2023
Biofertilisers	Rhizobium (legumes), Azotobacter, Azospirillum, Acetobacter (sugarcane), BGA and Azolla (paddy), PSB, mycorrhiza
Organic and natural	NPOP 2001 (APEDA); PGS-India; PKVY 2015; Sikkim 2016; NMNF Nov 2024
Pest management	ETL < EIL; 3Rs; Insecticides Act 1968; fall armyworm 2018; NIBSM Raipur

Start Learning

Begin with the first topic:

→ Crop Science and Cropping Systems