Nano-Urea: Impact, Benefits, and Concerns

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Role of Urea in Agriculture

Urea plays a crucial role in Indian agriculture as a primary nitrogen fertilizer, essential for the cultivation of staple crops like rice and wheat. The country requires around 350 lakh tonnes of urea annually, with 40 lakh tonnes being imported to meet the demand. To ensure affordability, urea is heavily subsidized, with a 45-kg bag costing ₹242, while its actual price is much higher. The Indian government spent approximately ₹1.3 lakh crore on urea subsidies in 2023-24, highlighting the financial burden of fertilizer support.

What is Nano-Urea?

Nano-urea is a liquid fertilizer containing 4% nitrogen (20g N per 500 ml bottle) and is introduced as a more efficient alternative to conventional urea. Unlike traditional granular urea, which is applied to the soil, nano-urea is sprayed directly onto plant leaves, aiming to enhance nitrogen absorption. It is composed of nanoparticles (20-50 nm in size), providing a higher surface area for better nutrient delivery. Developed as a potential solution to reduce urea consumption and imports, a bottle of nano-urea is priced at ₹260, slightly more than a traditional 45-kg bag.

Claimed Benefits of Nano-Urea

Nano-urea is promoted as an energy-efficient, environmentally friendly fertilizer with several advantages. It claims to improve nutrient-use efficiency by increasing nitrogen availability to crops by more than 80%, compared to only 25% in conventional urea. The efficiency of liquid nano-urea is estimated at 85-90%, which could help reduce excessive urea use and limit soil, water, and air pollution. Additionally, the foliar application method provides targeted nutrient delivery to plants, supporting better crop growth. The expected benefits include reducing the subsidy burden and preventing the indiscriminate use of nitrogen fertilizers.

Concerns Over Effectiveness

Recent studies have raised concerns over nano-urea’s long-term viability and effectiveness. Research trials revealed that nano-urea application led to a 35% reduction in rice protein content and a 24% decline in wheat protein content. Additionally, plant root development was adversely affected, showing reduced root length and dry weight, limiting nitrogen absorption from the soil. Findings also indicated that plants primarily depended on soil nitrogen, as nano-urea was ineffective in delivering sufficient nitrogen through foliar application alone. Even modified formulations with higher nitrogen content (8% and 20%) failed to improve crop yield, raising doubts about its overall efficiency.