Question map
Consider the following plants : 1. Groundnut 2. Horse-gram 3. Soybean How many of the above belong to the pea family ?
Explanation
The correct answer is option C - all three plants belong to the pea family (Fabaceae/Leguminosae).
Groundnut is a leguminous crop which adds valuable nitrogen to the soil[1], confirming its membership in the pea family. Horse-gram is listed among pulses[2], and pulses are major source of protein in Indian diet[2]. Pulses, by definition, are edible seeds of leguminous plants belonging to the Fabaceae family. Soybean is also a well-known legume and pulse crop that belongs to the pea family.
All leguminous crops share the characteristic ability to fix atmospheric nitrogen through root nodules containing symbiotic bacteria, which is why groundnut is often grown in rotation with other crops like millets, maize or cotton[1] to enrich soil fertility. Therefore, all three plants - groundnut, horse-gram, and soybean - are members of the pea family (Fabaceae).
Sources- [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Groundnuts or Peanut (Arachis hypogoea) and Groundnut (Arachis hypogaea) > p. 33
- [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Pulses or Grain Legumes > p. 353
PROVENANCE & STUDY PATTERN
Full viewThis is a 'Sitter' derived directly from NCERT Geography and basic Environment texts. It tests the fundamental definition of 'Leguminous Crops' (Nitrogen fixers). If you know which crops restore soil fertility, you know the answer.
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
- Explicitly describes groundnut as a 'leguminous crop', i.e., a member of the legume/pea group.
- Notes groundnut adds valuable nitrogen to the soil, a characteristic of leguminous (Fabaceae) plants.
- Section title is 'Pulses or Grain Legumes' and the listed items include 'Horsegram' and 'Soyabean'.
- Classifies horsegram and soybean within the pulse/legume category, linking them to the pea/legume family.
- [THE VERDICT]: Sitter. Found verbatim in NCERT Class X (Agriculture) and Shankar IAS (Agriculture Chapter). Missing this means you skipped the introductory lines of crop descriptions.
- [THE CONCEPTUAL TRIGGER]: 'Major Crops' and 'Nitrogen Cycle'. The examiner isn't asking for botanical trivia; they are asking about 'Nitrogen Fixers' which are crucial for sustainable agriculture.
- [THE HORIZONTAL EXPANSION]: Memorize the 'Dual-Purpose' crops (Legume + Oilseed): Soybean and Groundnut. Memorize the 'Fodder Legumes': Alfalfa (Lucerne), Berseem (Clover). Watch out for the trap: Rajma (Kidney Bean) is a legume but is a poor nitrogen fixer compared to others.
- [THE STRATEGIC METACOGNITION]: When reading crop profiles, tag them functionally: Is it a cereal (Gramineae)? Is it a legume (Fabaceae)? Is it a tuber? UPSC loves crossing these functional lines (e.g., 'Is Groundnut a pulse or oilseed?'). Answer: It's botanically a legume but commercially an oilseed.
Leguminous crops are identified as adding nitrogen to soil through biological fixation.
High-yield concept for geography/agriculture: explains crop rotation benefits, soil fertility topics, and supports questions on sustainable agriculture and cropping patterns; links to topics on pulses and farm management. Familiarity helps answer questions on why legumes are promoted in dryland and rotation systems.
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Groundnuts or Peanut (Arachis hypogoea) and Groundnut (Arachis hypogaea) > p. 33
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Pulses (Legumes) > p. 28
Pulses (grain legumes) list includes horsegram and soybean, making them members of the pea/legume grouping.
Useful for MCQs and short-answer questions on crop classification, nutritional/agricultural roles of pulses, and policy/production statistics; connects to questions on pulse cultivation regions and protein sources in the Indian diet.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Pulses or Grain Legumes > p. 353
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Pulses (Legumes) > p. 28
Some important oilseeds (groundnut, soybean) are also legumes, appearing in both oilseed and pulse contexts.
Helps answer questions on crop categorization, agricultural economies, and cropping patterns where a crop can be both an oilseed and a legume; useful for synthesis-type UPSC questions linking production, uses, and crop classification.
- NCERT. (2022). Contemporary India II: Textbook in Geography for Class X (Revised ed.). NCERT. > Chapter 4: The Age of Industrialisation > Food Crops other than Grains > p. 85
- INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 3: Land Resources and Agriculture > Oilseeds > p. 30
The 'Rajma Paradox'. While Rajma (Kidney Bean) belongs to the Legume family, it generally does NOT fix atmospheric nitrogen effectively in Indian soils because the specific Rhizobium strain is often absent. It is a likely future 'Exception Trap' statement.
Apply the 'Farmer's Logic': Which of these are grown in rotation to 'rest' the soil? Farmers specifically plant Horse-gram and Groundnut in dry seasons to restore soil health. If they restore soil, they must be nitrogen fixers (Legumes/Pea family). Since Soybean is the world's top protein source (like peas), 'All three' is the only logical bet.
Mains GS-3 (Agriculture): Use this in 'Integrated Nutrient Management'. Citing 'Legume-Cereal rotation' (using Groundnut/Soybean) reduces the need for Urea, lowers input costs for farmers, and mitigates N2O emissions (a potent greenhouse gas).