Syllabus
GS Paper 3 – Issues related to Direct and Indirect Farm Subsidies, Cropping Patterns in various parts of the country
Context
The Haber-Bosch process transformed agriculture dramatically.
Source
The Hindu| Editorial dated 15th October 2024
How did the Haber-Bosch process change the world?
The Haber-Bosch process revolutionized agriculture by synthesizing ammonia from nitrogen and hydrogen, meeting the world’s rising food demand. While the method increased food production significantly, it also has environmental consequences. This discussion explores nitrogen, its natural and industrial availability, the process of ammonia production, and the environmental impact of fertilizers.
What is the Nitrogen Molecule?
- Composition of N2: Nitrogen exists as N2 in the atmosphere, with two nitrogen atoms bonded by a triple bond, making it highly stable and difficult to break.
- Triple Bond Strength: The nitrogen triple bond requires 946 kJ/mol of energy to break, rendering N2 nearly inert and non-reactive under normal conditions.
- Formation of Reactive Nitrogen: Once the nitrogen bond is broken, it forms reactive nitrogen compounds such as ammonia (NH3), ammonium (NH4+), and nitrates (NO3–), which are essential for plant growth.
How is Nitrogen Availed in Nature?
- Lightning and Nitrogen Oxides: Lightning provides the energy needed to break nitrogen bonds, combining nitrogen with oxygen to form nitrogen oxides, which later form nitric and nitrous acids that fertilize the soil.
- Biological Nitrogen Fixation: Microorganisms such as Azotobacter and Rhizobia in symbiotic relationships with legumes convert atmospheric nitrogen into reactive nitrogen.
- Azolla and Nitrogen Fixation: Azolla ferns, with cyanobacterium Anabaena azollae, absorb nitrogen from the air, making them effective natural fertilizers when decomposed.
The Nitrogen Cycle
- Soil Absorption: Plants absorb reactive nitrogen from the soil in the form of ammonium (NH4+) and nitrate (NO3–).
- Return of Nitrogen: Nitrogen returns to the soil through decomposition of plants and animals, but part of it escapes back to the atmosphere as N2, leaving the cycle incomplete.
- Depletion of Nitrogen: Food crops like rice, wheat, and corn deplete nitrogen faster than it can be naturally replenished, necessitating the use of fertilizers.
Historical Use of Natural Fertilizers
- Legumes and Ammonia Fertilization : Farmers historically grew legumes or used ammonia to replenish soil nitrogen.
- Natural Nitrates: Naturally occurring ammonium-bearing minerals from volcanic eruptions and nitrates from caves and rocks were used as fertilizers.
- Volcanic Minerals: These minerals helped early farmers boost crop yields before the development of synthetic fertilizers.
How is Ammonia Made?
- Haber’s Early Experiments: Fritz Haber heated a mixture of nitrogen and hydrogen at various temperatures to produce ammonia, but early yields were too small for industrial use.
- The Role of Pressure: Haber realized that high pressure (200 atm) at lower temperatures (200°C) improved ammonia production, although the process remained slow.
- Catalysts and Efficiency: By using catalysts like osmium and later iron oxide, Haber successfully increased ammonia production, leading to the development of the industrial Haber-Bosch process.
What is the Haber-Bosch Process?
- High Pressure and Heat Transfer: The process involves circulating hydrogen and nitrogen at high pressure (200 atm) and utilizing heat transfer between incoming and outgoing gases to enhance efficiency.
- Discovery of Catalysts: Testing various catalysts, including osmium and iron oxides, allowed Haber and his team to crack the nitrogen triple bond efficiently.
- Scale-Up by BASF: BASF scaled up the process to industrial levels, opening the first ammonia factory in 1913, revolutionizing fertilizer production.
The Downsides of Fertilizers
- Excess Nitrogen Application: Modern fertilizer use often exceeds 50 kg of nitrogen per capita in many countries, far beyond the 1-2 kg of nitrogen found in human tissues.
- Environmental Damage: Excess nitrogen fertilizers contribute to surface runoff, over-fertilization of water bodies, deoxygenation, and acidification of rain, leading to land degradation.
- Inequality in Food Distribution: Despite the availability of fertilizers, starvation and malnutrition persist alongside grain surpluses due to social and political disparities.
Conclusion
The Haber-Bosch process was a groundbreaking innovation, pivotal to addressing global food demands. However, the overuse of nitrogen fertilizers has significant environmental consequences. The lesson from the nitrogen fixation saga is that technological advancements must be accompanied by social and political reforms to create sustainable and equitable solutions.
Related PYQ
What are the different types of agriculture subsidies given to farmers at the national and at state levels? Critically analyse the agricultural subsidy regime with reference to the distortions created by it. [ UPSC Civil Services Exam – Mains 2014]
Practice Question
The Haber-Bosch process played a crucial role in boosting agricultural productivity, but it also posed environmental challenges. Discuss the significance of the Haber-Bosch process and its environmental impact. Suggest measures to mitigate the adverse effects? [250 words]
Guidelines to Answer
- Introduction:
- Briefly introduce the Haber-Bosch process and its role in agricultural productivity.
- Body
- Explain how the process revolutionized agricultural productivity and enabled global population growth.
- Highlight its role in providing readily available nitrogen for non-legume crops.
- Discuss the negative effects of fertilizer overuse, such as water contamination from nitrogen runoff and soil degradation.
- Suggest policies for balanced and efficient use of fertilizers (e.g., precision farming, nutrient management).
- Conclusion
- Conclude by emphasizing the need for sustainable practices in agriculture to balance food security with environmental conservation.