Nitrogen Use Efficiency of Rice Varieties

Recent research by biotechnologists at Guru Gobind Singh Indraprastha University (GGU) in New Delhi has highlighted significant variations in nitrogen use efficiency (NUE) among popular rice varieties in India.

Key Findings

• Definition of NUE: Nitrogen Use Efficiency measures the yield of a crop relative to the nitrogen available to it, whether from natural sources or synthetic fertilizers.
• Variation Among Varieties: The study found that the NUE of the best-performing rice varieties is up to five times higher than that of the least efficient ones.
• Yield vs. NUE: While higher NUE indicates better utilization of nitrogen, it does not always correlate with the highest yields. Farmers often prefer varieties that offer the highest yields, which complicates the adoption of high NUE varieties.

Challenges in Indian Agriculture

• The primary focus of Indian agriculture has historically been on increasing crop yields, especially during the Green Revolution. This approach has led to:
• Increased dependence on synthetic fertilizers.
• Significant nitrogen wastage, costing approximately ₹1 trillion annually in India and over $170 billion globally.
• Environmental pollution from nitrogen fertilizers, which are major contributors to nitrous oxide (N₂O) and ammonia emissions. N₂O is a potent greenhouse gas, with a warming effect much greater than carbon dioxide.
• In 2020, India accounted for nearly 11% of global manmade N₂O emissions, making it the second-largest source after China.

Environmental Impact

• Fertilizer use is identified as the major source of N₂O emissions, impacting air quality, biodiversity, and contributing to climate change.
• This pollution poses risks to human health and the environment, necessitating urgent reforms in agricultural practices.

Way Ahead

• Diversity in Rice Varieties: India has a rich diversity of rice varieties, but agricultural research often focuses on a limited selection. Expanding research to include a broader range of varieties could uncover those with improved NUE and higher yields.
• Improving NUE: Enhancements in NUE could be achieved through:
• Better fertilizer formulations.
• Implementing legume-based crop rotations.
• Adopting innovative crop management practices.
• Biotechnology as a Solution: Leveraging biotechnology to develop new rice varieties that are both nitrogen-efficient and high-yielding can reduce reliance on imported fertilizers and mitigate nitrogen-related pollution.

Conclusion

To promote sustainable agriculture and protect the environment, it is essential to shift focus towards improving nitrogen use efficiency in rice production. This involves both traditional agricultural practices and modern biotechnological advancements, aiming for a more balanced approach to yield and resource efficiency.