Indian Biotechnologists have discovered a wide variation among popular varieties of rice in India in their ability to use nitrogen.
Background Context
- Historical Focus on Yield: Indian agriculture has historically prioritised yield over NUE, leading to increased synthetic fertiliser use and associated pollution.
- Lack of Variety Ranking: India lacks a ranking system for crop varieties based on NUE, hindering crop improvement through selection or breeding.
- Urea Consumption in India: Two-thirds of all urea in India is consumed by cereals, with rice being the primary contributor.
- Economic Impact: Poor nitrogen-use efficiency (NUE) in rice leads to wastage of urea worth ₹1 trillion annually in India and over $170 billion globally.
- Environmental Concerns: Nitrogen fertilisers are major sources of nitrous oxide (N2O) and ammonia pollution, impacting health, biodiversity, and climate change.
- Greenhouse Gas Emissions: India is the world’s second-largest emitter of nitrous oxide (N2O), largely due to fertiliser use, contributing significantly to global greenhouse gas emissions.
- Global Commitments: India is a signatory to the Kunming-Montreal Global Biodiversity Framework (2022), which mandates countries to halve their nutrient waste from all sources by 2030.
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Key Findings
- Study Findings: The study screened over a thousand rice varieties and identified significant NUE variation. Twenty parameters were found to strongly associate with NUE, including eight new parameters.
- Variation in NUE: The study found a five-fold variation in NUE among rice varieties. High NUE does not always correlate with the highest yields.
- Potential for Improvement: There is potential to improve NUE by exploring a wider range of rice varieties, including farmers’ landraces.
- Significance of this Discovery: This discovery can be used to develop newer varieties that use less nitrogen and are high-yielding, thus slashing expenditure on imported fertilisers and reducing nitrogen-linked pollution.
Nitrogen Use Efficiency (NUE)
- Nitrogen use efficiency refers to the yield of a crop relative to the nitrogen (natural and artificial) available to it.
- It is defined as the ratio of the amount of nitrogen effectively utilised by crops to the amount of nitrogen applied. It measures how well a plant uses nitrogen for growth and productivity.
Significance of NUE in Agriculture
- Optimising Crop Yields: Efficient nitrogen use is vital for maximising crop yields.
- Economic Impact of Poor NUE: Poor NUE leads to significant nitrogen fertiliser wastage, with costs estimated at Rs 1 lakh crore annually in India and over $170 billion globally.
- Environmental Consequences: Inefficient nitrogen management contributes to greenhouse gas emissions (e.g., nitrous oxide) and water body eutrophication, which harms aquatic ecosystems.
- Benefits of Enhanced NUE: Increasing NUE can enhance productivity and profitability for farmers by reducing fertiliser costs and minimising environmental impacts.
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Factors Affecting Nitrogen Use Efficiency (NUE)
- Genetics: Plant variety impacts NUE, influencing overall nitrogen utilisation efficiency.
- Soil Conditions: Soil type and health affect nitrogen uptake, impacting crop yields and fertiliser needs.
- Fertiliser Application: Type, timing, and method of application influence efficiency, affecting input costs and environmental impact.
- Crop Management: Practices like rotation and cover cropping improve NUE, enhancing productivity and reducing waste.
- Environmental Conditions: Weather and climate affect nitrogen utilisation, influencing plant growth and nutrient availability.
- Soil Microbes: Microbial activity affects nitrogen availability, influencing overall nutrient uptake and plant health.
Conclusion
Efforts should focus on leveraging biotechnology to enhance crop NUE. Additionally, large-scale screening of rice varieties is essential to identify cultivars with high NUE suitable for diverse agro climatic conditions.
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Nitrogen (N)
- About: Nitrogen, the predominant gas in Earth’s atmosphere, is crucial for life as it is found in soil, food, and our DNA.
- Nitrogen (N) is considered as an essential Macronutrient.
- A macronutrient is one of the essential nutrients required by plants in relatively large quantities for their growth and development.
- Significance of Nitrogen: It is essential for proteins, enzymes, chlorophyll, and DNA in plants, supports photosynthesis, amino acid production, and vital plant structures.
- Insufficient nitrogen leads to stunted growth, yellowing leaves, and reduced yields.
- Nitrogen fixation: Despite constituting 78% of the atmosphere, most organisms cannot directly utilise atmospheric nitrogen, necessitating conversion processes like nitrogen fixation.
- Nitrogen fixation is the process by which nitrogen is taken from its molecular form (N2) in the atmosphere and converted into nitrogen compounds useful for other biochemical processes.
- Fixation can occur through atmospheric (lightning), industrial, or biological processes.
- Nitrogen Pollution: It refers to the excessive presence of nitrogen compounds in the environment, often resulting from human activities such as agriculture, industrial processes, and transportation.
- This surplus of nitrogen can lead to various environmental problems, including water contamination, air pollution, and disruption of ecosystems.
- Sources of Nitrogen Pollution
- Agricultural Fertilisers: Overuse leads to nitrous oxide emissions, a potent greenhouse gas.
- Sewage: Contributes to nitrogen pollution when not properly treated.
- Food Waste: High in nitrogen, originating from both human and animal sources.
- Wastewater Treatment: Facilities without nitrogen removal processes can elevate nitrogen levels in water.
- Stormwater Runoff: Urban runoff carries nitrogen and phosphorus from roads and rooftops to water bodies.
- Fossil Fuel Usage: Diesel vehicles, despite cleaner technologies, still contribute to nitrogen pollution.
Impact of Nitrogen Pollution
- Disruption of Ecosystems: Aquatic Ecosystems suffer from toxic algal blooms and coastal dead zones, which threaten global biodiversity.
- Nitrogen pollution can cause Eutrophication.
- Eutrophication is a process in which a water body becomes overly enriched with nutrients, leading to plentiful growth of algae, plankton etc.
- Groundwater Pollution: Elevated nitrate levels contaminate drinking water sources.
- Soil Health Deterioration: Nitrogen pollution negatively affects soil quality and fertility.
- Contribution to Climate Change: Fertilisers and agricultural emissions release nitrous oxide and ammonia, contributing to greenhouse gas emissions and fine particulate matter pollution.
- Health Risks: High nitrate levels in water increase risks of methemoglobinemia in infants and cancer in adults.
- Methemoglobin is a form of haemoglobin that cannot carry oxygen. In methemoglobinemia, tissues cannot get enough oxygen.
- Ammonia emissions worsen air pollution, adversely affecting human health.
Steps Taken at the International level to Control Nitrogen Pollution:
- International Nitrogen Initiative: Platform for sustainable nitrogen management, founded in 2003.
- It was set up in 2003 under sponsorship of the Scientific Committee on Problems of the Environment (SCOPE) and from the International Geosphere-Biosphere Program (IGBP).
- Gothenburg Protocol (1999): Agreement to reduce emissions of key pollutants, including nitrogen oxides.
- South Asia Nitrogen Hub (SANH): Connects 32+ research organisations from across South Asia and the UK to tackle nitrogen issues.
- Colombo Declaration: Aims to halve nitrogen waste by 2030.
India’s Initiative:
- Neem-Coated Urea: Neem-Coated Urea is a fertiliser and an agriculture scheme supported by the Government of India to boost the growth of wheat and paddy, and curb the black market and hoarding of urea
- Its use is made mandatory to improve nitrogen use efficiency by slowing nitrogen release for better plant absorption.
- Soil Health Card: A soil health card provides information on the nutrient status of soil, along with recommendations on the dosage of nutrients to be utilised for improving its fertility and health.
- This card provides soil nutritional insights and nutrient application recommendations, reducing nitrogen consumption in agriculture.
- Bharat Stage Norms: The Bharat Stage (BS) are emission standards instituted by the Government of India to regulate the output of air pollutants from motor vehicles.
- These norms regulate vehicular emissions of harmful gases, including sulphur dioxide (SO₂) and nitrogen dioxide (NO₂).
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August 12, 2024
