Strategic Switching from Conventional Urea to Nano-Urea for Sustaining the Rice–Wheat Cropping System

Abstract

In the face of declining crop yields, inefficient fertilizer usage, nutrient depletion, and limited water availability, the efficiency of conventional NPK fertilizers is a critical issue in India. The hypothesis of this study posits that nano-nitrogen could enhance growth and photosynthetic efficiency in crop plants compared to conventional fertilizers. For this, a randomized block design (RBD) field experiment was conducted with six treatments: no nitrogen (T1), 100% N through urea (T2), and varying levels of N replacement with nano-nitrogen (33%: T3; 50%: T4; 66%: T5; and 100%: T6). Morphological and physiological traits and yield attributes were measured at physiological maturity, and yield attributes were measured at harvest. Results showed that 33% nitrogen replacement with nano-nitrogen (T3) outperformed conventional urea (T2) in physiological traits and achieved higher grain yields (3789 kg/ha for rice and 4206 kg/ha for wheat) compared to T2 (3737 kg/ha for rice and 4183 kg/ha for wheat with 100% urea). Although T4 and T5 showed statistically similar yields, they were lower than T2 and T3 for rice, while 50%, 66%, and 100% replacements reduced wheat yield by 2.49%, 8.39%, and 41.26%, respectively, compared to T2. Key enzymes of N metabolism decreased with higher nano-nitrogen substitution. Maximum nitrogen availability was observed in T2 and T3. This study concludes that nano-nitrogen is an effective strategy to enhance growth, balancing productivity and environmental sustainability.

Keywords

• nano-nitrogen
• physiological traits
• yield
• N-metabolizing enzymes
• available soil N