Substitution of soil urea fertilization to foliar nano urea fertilization decreases growth and yield of rice and wheat

Conventional nitrogen (N) fertilizers are prone to losses through leaching, volatilization, and denitrification, leading to low N-use efficiency (NUE). This study evaluates a new urea nano-formulation of IFFCO (Indian Farmers Fertilizer Cooperative Limited) as a potential substitute for commercial urea and its effects on rice and wheat performance.

A two-year field study evaluated the impact of two foliar sprays of IFFCO nano-urea (4 ml/l) in combination with 0% and 50% recommended doses of N-fertilizer (RDN) on the performance of rice and wheat grown in rotation. Agronomic parameters were measured every 30 days, and grain yield was recorded at harvest.

The application of two sprays of nano urea + 50% RDN significantly reduced the grain yield of rice and wheat by 13 and 17.2%, respectively, compared with 100% RDN application to soil. Additionally, chlorophyll content (SPAD), dry matter accumulation, tiller density, root growth, and macronutrient content decreased in both the test crops. The nano-urea + 50% RDN treatment exhibited 35% and 24% reduction in grain protein content in rice and wheat, respectively. The activity of glutamine synthetase and glutamate synthase in rice leaves decreased by 28.6 and 94.4%, respectively, compared to100% RDN treatment.

Nano-urea in combination with 50% RDN did not improve nitrogen use efficiency as claimed. More research studies are required to establish the correct crop-specific agronomy of this formulation. Thus, the focus should be on improving existing nitrogen management strategies and research to refine nano-urea formulations for better performance under field conditions.