16-August-2024-Special-Article

NITROGEN USE EFFICIENCY (NUE)

Recent advancements in biotechnology have led to the discovery of significant variation in nitrogen-use efficiency (NUE) among popular Indian rice varieties.

This discovery has paved the way for the development of high-yielding, low-nitrogen varieties, which can help reduce fertilizer costs and mitigate environmental pollution.

Additionally, the Prime Minister of India has introduced 109 high-yielding, climate-resilient, biofortified seed varieties, developed by the Indian Council of Agricultural Research (ICAR), aimed at enhancing farm productivity and increasing farmers’ incomes.

Nitrogen Use Efficiency (NUE)

Definition:

• NUE refers to the effectiveness of a plant in utilizing the available nitrogen, whether from the soil or fixed from the atmosphere, for biomass production.
• It is typically measured as the ratio between the crop yield and the amount of nitrogen absorbed by the plant.

Importance in Agriculture:

• NUE is particularly significant in cereal crops like rice, where efficient nitrogen use is a key factor in sustainable agriculture.

Concerns:

• Poor NUE leads to significant economic losses, with India alone wasting nitrogen fertilizers worth approximately Rs 1 lakh crore annually. Globally, the figure stands at over USD 170 billion per year.
• Inefficient nitrogen usage contributes to pollution, with fertilizers being a major source of nitrous oxide and ammonia, both of which harm air and water quality.
• India is the second-largest emitter of nitrous oxide (N2O), a potent greenhouse gas, contributing nearly 11% of global human-made emissions in 2020, following China.

Nitrogen Pollution

Nitrogen pollution occurs when nitrogen compounds, such as ammonia and nitrous oxide, accumulate excessively in the environment, posing health and ecological risks.

Causes:

• Human activities have increased reactive nitrogen flows tenfold over the past 150 years, resulting in a significant buildup of unused reactive nitrogen.
• Crops only absorb a limited amount of the nitrogen applied as fertilizer. Annually, about 80% of the 200 million tonnes of reactive nitrogen used globally is lost to the environment.

Effects:

• Climate Change: Nitrous oxide is 300 times more potent than carbon dioxide as a greenhouse gas and significantly threatens the ozone layer.
• Biodiversity: Excessive nitrogen leads to soil acidification, reducing soil health and productivity. It can also cause the over-fertilization of ecosystems, leading to the dominance of nitrogen-tolerant species and the decline of more sensitive plants and fungi.
• Water and Air Pollution: Nitrogen pollution creates “dead zones” in oceans and promotes harmful algal blooms. On land, nitrogen oxides contribute to smog and ground-level ozone, while agricultural ammonia emissions, combined with vehicle exhaust, form dangerous particulate matter, exacerbating respiratory diseases.

Biofortified Seed Varieties by ICAR

The Indian Council of Agricultural Research (ICAR) has developed 109 biofortified seed varieties covering 61 crops, including cereals, millets, oilseeds, pulses, and horticultural varieties. These seeds are designed to enhance crop yield and resilience to climate change.

Examples of Biofortified Varieties:

• CR Dhan 416: A rice variety suited for coastal saline areas, offering resistance to multiple diseases and pests, including the brown plant hopper and stem borer.
• Durum Wheat Variety: Suitable for irrigated conditions in Maharashtra, Karnataka, and Tamil Nadu, this variety is heat-tolerant, rust-resistant, and biofortified with higher levels of zinc and iron, along with 12% protein content.

Biofortification

Biofortification involves increasing the nutrient content of food crops through conventional breeding, agronomic practices, and modern biotechnology, without compromising consumer-preferred characteristics.

Importance:

• Biofortification is a critical strategy in addressing malnutrition, particularly in regions like India, where there are high rates of anemia and vitamin deficiencies.
• The process enhances crop resilience to pests, diseases, and environmental stressors, making them more sustainable and cost-effective.

Examples of Biofortification Projects:

• Iron-Biofortification: Applied to rice, beans, sweet potatoes, cassava, and legumes to address iron deficiencies.
• Zinc-Biofortification: Targeted at crops like wheat, rice, and maize to combat zinc deficiencies.
• Provitamin A Carotenoid-Biofortification: Focused on crops like sweet potatoes, maize, and cassava to provide vitamin A.

Need for Biofortification

Malnutrition:

• High levels of malnutrition persist in India, with significant deficiencies in iron, vitamin A, and iodine, particularly among women and children. Biofortification can play a crucial role in reducing these deficiencies.

Disease Resistance:

• Biofortified crops often exhibit enhanced resistance to diseases, pests, and extreme weather conditions, contributing to higher yields and agricultural sustainability.

Sustainability:

• Once developed, biofortified seeds maintain their nutrient density over generations, making them a sustainable solution to nutrient deficiencies.

Cultural Acceptance:

• Biofortified crops do not require changes in dietary habits or cultural practices, making them an easily adoptable solution for nutrient enrichment.

Cost-Effectiveness:

• Biofortification is a cost-effective method of addressing malnutrition, with the potential for high economic returns. According to the Copenhagen Consensus, every rupee spent on fortification yields nine rupees in economic benefits.

Conclusion

The discoveries in nitrogen-use efficiency among Indian rice varieties and the development of biofortified seed varieties by ICAR are significant strides toward sustainable agriculture and improved public health.

Enhancing NUE can reduce the environmental and economic costs associated with nitrogen fertilizers, while biofortification offers a viable solution to malnutrition and nutrient deficiencies. These innovations are critical in addressing the challenges of climate change, food security, and sustainable development.

Mains Question:

Q. “Discuss the significance of Nitrogen Use Efficiency (NUE) and biofortified seed varieties in promoting sustainable agriculture in India. (150 WORDS)