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Q30 (IAS/2020) Environment & Ecology › Pollution & Conservation › Sustainable agriculture practices Official Key

What is the use of biochar in farming ? 1. Biochar can be used as a part of the growing medium in vertical farming. 2. When biochar is a part of the growing medium, it promotes the growth of nitrogen-fixing microorganisms. 3. When biochar is a part of the growing medium, it enables the growing medium to retain water for longer time. Which of the statements given above is/are correct ?

Result
Your answer: —  ·  Correct: D
Explanation

The correct answer is Option 4 (1, 2 and 3) because all three statements accurately describe the functional benefits of biochar in modern agriculture.

  • Statement 1 is correct: Biochar’s lightweight nature and high porosity make it an ideal component for the growing medium in vertical farming. It provides structural support while reducing the overall weight of the system.
  • Statement 2 is correct: Biochar has a high surface area and porous structure that acts as a habitat for beneficial soil microbes. It specifically carbon-sequestrates and improves soil aeration, which promotes the growth of nitrogen-fixing microorganisms like Rhizobia, enhancing soil fertility.
  • Statement 3 is correct: Due to its extreme porosity, biochar acts like a sponge. It significantly increases the water-holding capacity of the growing medium, enabling plants to survive longer periods between watering and reducing nutrient leaching.

Since biochar enhances physical structure, biological activity, and moisture retention simultaneously, all statements are technically sound.

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Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.
Q. What is the use of biochar in farming ? 1. Biochar can be used as a part of the growing medium in vertical farming. 2. When biochar is a …
At a glance
Origin: Mostly Current Affairs Fairness: Low / Borderline fairness Books / CA: 0/10 · 3.3/10

This is a classic 'Applied Agriculture' question. While standard books define Vertical Farming and Nitrogen Fixation separately, they don't explicitly link Biochar to them. You must bridge the gap: Biochar is essentially a 'permanent carbon sponge.' If you understand its physical structure (porous), the answers flow logically.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
In farming, can biochar be used as part of the growing medium in vertical farming?
Origin: Weak / unclear Fairness: Borderline / guessy
Indirect textbook clues
Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > VERTICAL FARMING > p. 310
Strength: 5/5
“In vertical farming, crops are grown indoors, under artificial conditions of light and temperature. It aims at higher productivity in smaller spaces. It uses soil-less methods such as hydroponics, aquaponics and aeroponics. Vertical farming uses significantly less water and pesticides than traditional agricultural methods.”
Why relevant

Defines vertical farming as indoor production using soil-less methods (hydroponics, aquaponics, aeroponics), implying choice and design of growing media is a key consideration.

How to extend

A student could combine this with basic facts about biochar (that it is a solid amendment/medium) to ask whether a solid amendment can be integrated into or replace components of soil-less mixes or soilless substrates used in vertical systems.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Eco-farming: > p. 361
Strength: 4/5
“It is the farming mutually reinforcing ecological approaches to food production. It aims at the maintenance of soil chemically, biologically and physically, as nature would do if left alone. Soil would then take proper care of plants growing on it. Feed the soil, not the plant is the watchword and slogan of ecological farming. • Organic Fertilizers: Three common forms: animal manure, green manure and compost. Inorganic Fertilizer: Does not add humus to the soil, resulting in less ability to hold water and support living organisms (earthworms, beneficial bacteria, and fungi, etc.) All rights reserved. No part of this material may be reproduced in any form or by any means, without permission in writing.”
Why relevant

Highlights that organic fertilizers and compost add humus and improve water-holding and biological properties of growing material.

How to extend

A student could compare the functional role of organic amendments with known properties of biochar (water retention, habitat for microbes) to assess whether biochar might play a similar amendment role in a growing medium.

Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 11: Agriculture - Part II > 11.9 Organic Farming > p. 345
Strength: 4/5
“Introduction: Organic farming is a form of agriculture that relies on techniques such as crop rotation, green manure, and biological pest control. It is a method of farming system which primarily aims at cultivating the land and raising crops in such a way, as to keep the soil alive and in good health by use of organic wastes and other biological materials along with beneficial microbes (bio fertilizers) to release nutrients to crops for increased sustainable production in an eco-friendly pollution free environment. This is a method of farming that works at grass root level preserving the reproductive and regenerative capacity of the soil, good plant nutrition and sound soil management, produces nutritious food rich in vitality which has resistance to diseases.”
Why relevant

Describes organic farming relying on organic wastes and biological materials with microbes to release nutrients—showing that growing media often combine inert matrix plus biological nutrient sources.

How to extend

A student could consider whether biochar could serve as an inert matrix or carrier for microbes/nutrients within a vertical farming substrate.

Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 26: Agriculture > Soil Conservation and Sound Farming Techniques > p. 244
Strength: 3/5
“This is much practised in the semi-arid lands under the system of dry farming both to conserve ground moisture and to replenish soil nutrients 9. Soil additives. Farmers are all aware that by adding manures or fertilizers to the soil, its fertility can be maintained. Organic manures, like cow-dung, bird droppings, green manure, farm wastes, compost and other decayed vegetation, are readily available in the farm and when applied in suitable quantities always increase crop yields.”
Why relevant

States that adding organic manures, compost and decayed vegetation to soil increases crop yields—demonstrating that additives to a growing medium are a common, yield-impacting practice.

How to extend

A student could investigate whether biochar, as an additive, could similarly affect moisture/nutrient dynamics in confined vertical growing media.

Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 10: Locational Factors of Economic Activities > Salient Features > p. 21
Strength: 3/5
“Sustainable agriculture has to prevent land degradation and soil erosion. It has to be replenish nutrients and control weeds, pests and diseases through biological and cultural methods. Sustainable agriculture is also known as enforcing organic farming or natural farming or permaculture. It is known as eco-farming as ecological balance is given importance. It is also called organic farming as organic matter is the main source of nutrient management. But some scientists consider that it is a misconception to think that sustainable agriculture is farming without chemical inputs. It is considered by some as integrated, low input and highly productive farming system.”
Why relevant

Links sustainable agriculture to using organic matter as the main source of nutrient management, indicating emphasis on medium composition for plant nutrition.

How to extend

A student could use this rule to frame questions about biochar's potential role in nutrient management within intensive systems like vertical farms.

Statement 2
In farming, does adding biochar to a growing medium promote the growth or abundance of nitrogen‑fixing microorganisms?
Origin: Weak / unclear Fairness: Borderline / guessy
Indirect textbook clues
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Bio-fertilizers > p. 364
Strength: 5/5
“o Bio-fertilizers are the preparations containing live or latent cells of efficient strains of nitrogen fixing, phosphate solubilizing or cellulolytic microorganisms used for application to seed or composting areas with the objective of increasing the numbers of such micro-organisms and accelerating those microbial processes which augment the availability of nutrients that can be easily assimilated by plants”
Why relevant

Defines bio‑fertilisers as preparations applied to seed/compost to increase numbers of nitrogen‑fixing microorganisms and accelerate microbial processes that make nutrients available.

How to extend

A student could infer that adding any amendment designed to increase microbial populations (like bio‑fertilisers) can raise N‑fixer abundance and test whether biochar acts similarly by measuring N‑fixer counts after amendment.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > vi) Composting , > p. 86
Strength: 4/5
“• Composting is a biological process in which micro-organisms, mainly fungi and bacteria, decompose degradable organic waste into humus-like substance in the presence of oxygen. • This finished product, which looks like soil, is high in carbon and nitrogen and is an excellent medium for growing plants. • It increases the soil's ability to hold water and makes the soil easier to cultivate. It helps the soil retain more plant nutrients.”
Why relevant

Describes composting as a biological process producing a high‑carbon, high‑nitrogen medium that is an excellent plant growing medium and enhances soil's ability to hold water and nutrients.

How to extend

Since organic amendments that improve habitat and nutrient retention promote microbial activity, a student could compare biochar's effects on soil water/nutrient retention and correlate with N‑fixer abundance.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Eco-farming: > p. 361
Strength: 4/5
“It is the farming mutually reinforcing ecological approaches to food production. It aims at the maintenance of soil chemically, biologically and physically, as nature would do if left alone. Soil would then take proper care of plants growing on it. Feed the soil, not the plant is the watchword and slogan of ecological farming. • Organic Fertilizers: Three common forms: animal manure, green manure and compost. Inorganic Fertilizer: Does not add humus to the soil, resulting in less ability to hold water and support living organisms (earthworms, beneficial bacteria, and fungi, etc.) All rights reserved. No part of this material may be reproduced in any form or by any means, without permission in writing.”
Why relevant

Notes inorganic fertilizers do not add humus and reduce the soil's ability to support living organisms including beneficial bacteria and fungi.

How to extend

This contrast suggests amendments that increase humus or habitat (potentially including biochar) might boost beneficial microbes; one could test whether biochar behaves more like organic amendments or inert inorganic inputs with respect to N‑fixers.

FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 5: Geomorphic Processes > Biological Activity > p. 45
Strength: 3/5
“Further, bacteria and other soil organisms take gaseous nitrogen from the air and convert it into a chemical form that can be used by plants. This process is known as nitrogen fixation. Rhizobium, a type of bacteria, lives in the root nodules of leguminous plants and fixes nitrogen beneficial to the host plant. The influence of large animals like ants, termites, earthworms, rodents etc., is mechanical, but, it is nevertheless important in soil formation as they rework the soil up and down. In case of earthworms, as they feed on soil, the texture and chemistry of the soil that comes out of their body changes.”
Why relevant

Explains that soil bacteria (e.g., Rhizobium) fix atmospheric nitrogen and that soil organisms and soil texture/chemistry changes (e.g., by earthworms) influence soil and its biology.

How to extend

A student could use the principle that changes in soil texture/chemistry affect N‑fixers to evaluate whether biochar's known effects on soil pH, porosity or chemistry (from outside knowledge) are likely to promote Rhizobium or other N‑fixers.

Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > Table 2.4: Testing for curd formation using milk in different conditions > p. 22
Strength: 3/5
“That is why curd is formed in bowl A but not in bowl B. We can categorise the microorganisms into different categories, such as protozoa, fungi, bacteria, some algae, and more. Some bacteria, such as Rhizobium, form the swollen regions called nodules and live in them as shown in Fig. 2.12. Roots of certain legumes, such as beans, peas, and lentils have root nodules that contain Rhizobium bacteria. These bacteria trap nitrogen from the air and make it useful for the plants. This helps plants grow better without chemical fertilisers. That is why farmers grow legumes in rotation with other crops.”
Why relevant

Describes Rhizobium living in legume root nodules and helping plants grow without chemical fertilisers, illustrating that fostering N‑fixers can substitute for added N.

How to extend

A student could extend this by testing whether biochar addition increases legume nodulation or measurable N fixation rates compared with untreated soil.

Statement 3
In farming, does incorporating biochar into a growing medium increase the medium's water retention?
Origin: Web / Current Affairs Fairness: CA heavy Web-answerable

Web source
Presence: 5/5
"As with increased soil (organic) carbon, discussed above, biochar can increase soil water retention, thereby enhancing the resilience of ecosystems and potentially mitigating the water-depleting effects of climate change in arid areas."
Why this source?
  • Directly states that biochar can increase soil water retention.
  • Frames increased water retention as a benefit that enhances ecosystem resilience and helps in arid areas.
Web source
Presence: 3/5
"The impacts of long-term storage of biochar (charcoal) in different soil types and under different environmental conditions are not well understood. Important issues that need to be resolved include the stability of carbon in the biochar, and effects on soil water retention, N2O release, crop yields, mycorrhizal fungi, soil microbial communities and detritivores."
Why this source?
  • Notes that the impacts of biochar on soil properties — including soil water retention — are not well understood.
  • Indicates uncertainty and the need for further resolution about effects on water retention across different soils and conditions.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > vi) Composting , > p. 86
Strength: 5/5
“• Composting is a biological process in which micro-organisms, mainly fungi and bacteria, decompose degradable organic waste into humus-like substance in the presence of oxygen. • This finished product, which looks like soil, is high in carbon and nitrogen and is an excellent medium for growing plants. • It increases the soil's ability to hold water and makes the soil easier to cultivate. It helps the soil retain more plant nutrients.”
Why relevant

Defines compost as producing a humus-like, carbon‑rich product that 'increases the soil's ability to hold water.'

How to extend

A student could note that biochar is also a carbon-rich soil amendment and test whether it similarly raises soil water-holding capacity in lab or field trials.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Role of manures > p. 363
Strength: 5/5
“• r. Organic manures bind the sandy soil and improve its water holding capaciry. • z. They open the clayey soil and help in aerati6h better root growth. • 3. They add plant nutrients in small percentage and also add micro nutrients which are essential for plant growth. The microbial activity is increased, which helps in releasing plant nutrients available for e.g. A11 Rights Reserved. No part of this material nay be reproduced in anv ibrrl or b,v atry means, lvithout Permission in 1\'riting. rc$”
Why relevant

States organic manures 'bind the sandy soil and improve its water holding capacity' and improve clay aeration — showing organic amendments alter water retention by changing texture/structure.

How to extend

One can compare biochar's physical effects on sandy vs. clayey media to see if it mimics the binding/structure changes described for organic manures.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Eco-farming: > p. 361
Strength: 4/5
“It is the farming mutually reinforcing ecological approaches to food production. It aims at the maintenance of soil chemically, biologically and physically, as nature would do if left alone. Soil would then take proper care of plants growing on it. Feed the soil, not the plant is the watchword and slogan of ecological farming. • Organic Fertilizers: Three common forms: animal manure, green manure and compost. Inorganic Fertilizer: Does not add humus to the soil, resulting in less ability to hold water and support living organisms (earthworms, beneficial bacteria, and fungi, etc.) All rights reserved. No part of this material may be reproduced in any form or by any means, without permission in writing.”
Why relevant

Contrasts organic fertilizers (which add humus and improve water-holding) with inorganic fertilizers (which do not), implying organic carbon additions tend to increase water retention.

How to extend

Use the rule that organic carbon additions improve water retention to hypothesize biochar (a form of stable carbon) could have similar effects, then measure field capacity or available water.

Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 26: Agriculture > Soil Conservation and Sound Farming Techniques > p. 244
Strength: 4/5
“This is much practised in the semi-arid lands under the system of dry farming both to conserve ground moisture and to replenish soil nutrients 9. Soil additives. Farmers are all aware that by adding manures or fertilizers to the soil, its fertility can be maintained. Organic manures, like cow-dung, bird droppings, green manure, farm wastes, compost and other decayed vegetation, are readily available in the farm and when applied in suitable quantities always increase crop yields.”
Why relevant

Notes that adding manures/compost/decayed vegetation increases crop yields and is used to conserve ground moisture in dry farming—linking soil amendments, moisture conservation and structure.

How to extend

Apply this pattern to design experiments comparing soils with and without biochar under dry‑farming conditions to observe moisture retention and crop responses.

Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 11: Irrigation in India > 2 1. Surface Irrigation > p. 362
Strength: 3/5
“In this method water is distributed through gravity flow. This method is best suited to flat land, slopes and to medium or fine textured soils like loamy or clayey soil. It is difficult to uniformly distribute water in the long fields with coarse textured soils like gravels and sands. Generally, this method is more labour intensive than other methods of irrigation. This method is widely used because of its simple mechanisms and low maintenance.”
Why relevant

Explains that soil texture (coarse vs. fine) affects water distribution and retention, so amendments that change texture/aggregation can alter water behavior.

How to extend

Combine this textural rule with biochar's known effects on porosity/aggregation (from outside facts) to predict where biochar might most increase water retention (e.g., coarse/sandy soils) and then test.

Pattern takeaway: UPSC consistently asks about 'Eco-friendly Agricultural Innovations' (e.g., System of Rice Intensification, Fertigation, Zero Tillage). If a technology is sustainable and the statements describe plausible positive benefits (water retention, microbial growth), the answer is usually 'All of the above'.
How you should have studied
  1. [THE VERDICT]: Logical Bouncer. Not in standard texts, but solvable via 'Science & Tech Optimism' and basic properties of carbon. Source: DownToEarth/The Hindu Science pages.
  2. [THE CONCEPTUAL TRIGGER]: Sustainable Agriculture & Climate Smart Farming (specifically Soil Amendments).
  3. [THE HORIZONTAL EXPANSION]: 1. Pyrolysis (process to make biochar). 2. Carbon Sequestration (Biochar is stable for 100s of years vs compost). 3. Terra Preta (Amazonian dark soils). 4. Hydroponic substrates (Perlite, Vermiculite, Coco peat - Biochar is a substitute). 5. N-fixers: Rhizobium (symbiotic), Azotobacter (free-living).
  4. [THE STRATEGIC METACOGNITION]: Do not memorize lists of uses. Master the 'Mechanism of Action'. Biochar = Porous Carbon Skeleton. Does a skeleton hold water? Yes. Does it house microbes? Yes. Is it a solid medium? Yes. Therefore, All Correct.
Concept hooks from this question
📌 Adjacent topic to master
S1
👉 Soil‑less cultivation methods (hydroponics, aquaponics, aeroponics)
💡 The insight

Vertical farming commonly employs soil‑less systems as its primary growing media approach.

High-yield for UPSC because questions often ask distinctions between farming technologies and their resource implications; links to urban agriculture, water use efficiency, and technology policy. Mastering this enables candidates to answer Qs on types of vertical farming, comparative advantages, and suitability of growing media.

📚 Reading List :
  • Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > VERTICAL FARMING > p. 310
🔗 Anchor: "In farming, can biochar be used as part of the growing medium in vertical farmin..."
📌 Adjacent topic to master
S1
👉 Soil additives and organic manures
💡 The insight

Use of manures, compost and other organic additives is a core method to modify growing media and maintain fertility in farming systems.

Important for questions on soil health, sustainable agriculture and nutrient management; connects to topics like organic farming, soil conservation and productivity. Knowing types and functions of additives helps evaluate alternative media (including potential use cases) and policy choices for sustainable inputs.

📚 Reading List :
  • Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 26: Agriculture > Soil Conservation and Sound Farming Techniques > p. 244
🔗 Anchor: "In farming, can biochar be used as part of the growing medium in vertical farmin..."
📌 Adjacent topic to master
S1
👉 Difference between organic farming and natural farming (ZBNF)
💡 The insight

Organic farming accepts external organic inputs while natural farming avoids added fertilizers, highlighting different approaches to adding or avoiding amendments to growing media.

Valuable for UPSC because it clarifies policy debates and schemes promoting organic practices versus zero-budget/no-input models; useful for questions comparing sustainability models, cost implications, and on‑farm practices. Understanding this distinction aids analysis of suitability of inputs in constrained systems (e.g., vertical vs field farming).

📚 Reading List :
  • Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 11: Agriculture - Part II > Differences between Organic Farming and ZBNF: > p. 349
  • Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 11: Agriculture - Part II > Differences between Organic Farming and ZBNF: > p. 350
🔗 Anchor: "In farming, can biochar be used as part of the growing medium in vertical farmin..."
📌 Adjacent topic to master
S2
👉 Bio‑fertilizers and nitrogen‑fixing microbes
💡 The insight

Bio‑fertilizers are preparations that contain live nitrogen‑fixing microorganisms intended to increase their numbers and enhance nutrient availability in soils.

High‑yield for questions on sustainable agriculture and soil fertility management; links to government promotion of biological inputs and reductions in chemical fertilizer use. Mastery helps answer questions on types, functions, and benefits of bio‑inputs and policy measures promoting them.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Bio-fertilizers > p. 364
🔗 Anchor: "In farming, does adding biochar to a growing medium promote the growth or abunda..."
📌 Adjacent topic to master
S2
👉 Rhizobium and biological nitrogen fixation
💡 The insight

Rhizobium bacteria form root nodules on legumes and convert atmospheric nitrogen into forms plants can use, thereby enhancing soil nitrogen naturally.

Essential for questions on crop rotations, legume cultivation, and reducing dependence on synthetic nitrogen fertilizers; connects to ecology, agronomy and environmental implications of agricultural practices.

📚 Reading List :
  • FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 5: Geomorphic Processes > Biological Activity > p. 45
  • Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > Table 2.4: Testing for curd formation using milk in different conditions > p. 22
  • Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > Snapshots > p. 25
🔗 Anchor: "In farming, does adding biochar to a growing medium promote the growth or abunda..."
📌 Adjacent topic to master
S2
👉 Organic amendments (compost) and soil microbial activity
💡 The insight

Compost and organic manures increase soil carbon and nitrogen, improve water‑holding capacity, and create a better medium for microbial decomposition and plant growth.

Useful for questions contrasting organic vs inorganic fertilizers and for policy/strategy questions on soil health and ecological farming; links to topics on soil structure, moisture retention, and biological maintenance of fertility.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > vi) Composting , > p. 86
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Eco-farming: > p. 361
🔗 Anchor: "In farming, does adding biochar to a growing medium promote the growth or abunda..."
📌 Adjacent topic to master
S3
👉 Organic amendments increase soil water-holding capacity
💡 The insight

Adding organic matter such as compost or manure increases a medium's ability to retain water.

High-yield for questions on soil management and irrigation: explains how organic inputs improve moisture availability, drought resilience and influence irrigation needs. Connects to soil fertility, nutrient cycling and sustainable farming practices; useful for questions comparing organic vs inorganic inputs.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > vi) Composting , > p. 86
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Role of manures > p. 363
🔗 Anchor: "In farming, does incorporating biochar into a growing medium increase the medium..."
🌑 The Hidden Trap

Torrefaction. Since Biochar (Pyrolysis) was asked, the next logical step is 'Torrefied Biomass' (biocoal), which is roasted at lower temperatures to increase energy density for fuel, unlike Biochar which is for soil.

⚡ Elimination Cheat Code

The 'Possibility Modal' Hack. Statement 1 uses 'Can be used'. In Science & Tech, 'Can be' is almost always true unless the application is physically impossible (e.g., 'Biochar can be used as rocket fuel'). Statements 2 and 3 describe generic positive attributes of porous organic matter. When in doubt with eco-tech, go for 'All Correct'.

🔗 Mains Connection

Links Geography (Agriculture) to GS3 Environment (Climate Change Mitigation). Biochar is not just farming; it is a 'Negative Emission Technology' (NET) recognized by the IPCC for locking atmospheric carbon into the soil for centuries.

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SIMILAR QUESTIONS

NDA-I · 2015 · Q47 Relevance score: 0.39

Which of the following are the charac- teristics of organic farming ? 1. Use of chemical fertilizers to improve soil fertility. 2. Frequent decomposing and fal- lowing. 3. Use of herbs to control pests. 4. Higher productivity per hectare. Select the correct answer using the code given below :

CDS-II · 2010 · Q24 Relevance score: -0.37

Which among the following statements about bio fertilizers are correct ? . 1. Azotobacter is one of the Nitrogen fixing bacteria used as a bio fertilizer. 2. They have to be applied to the leaves of the plant only. 3. They alter the chemical composition of the soil. 4. They can be used along with organic fertilizers. Select the correct answer using the code given below :

IAS · 2015 · Q11 Relevance score: -0.49

What can be the impact of excessive/inappropriate use of nitrogenous fertilizers in agriculture? 1. Proliferation of nitrogen-fixing microorganisms in soil can occur. 2. Increase in the acidity of soil can take place. 3. Leaching of nitrate to the groundwater can occur. Select the correct answer using the code given below.

IAS · 2013 · Q8 Relevance score: -0.58

Consider the following organisms: 1. Agaricus 2. Nostoc 3. Spirogyra Which of the above is/are used as biofertilizer / biofertilizers?