Effect of nano urea-based nitrogen management on growth, yield, and economics in safflower (Carthamus tinctorius L.)

Abstract

Safflower (Carthamus tinctorius L.) is an important oilseed crop valued for its edible oil and industrial applications, but its productivity is often constrained by sub-optimal nitrogen (N) management. Nano urea, developed using nanotechnology, has emerged as a novel fertilizer with higher foliar absorption efficiency and potential to enhance crop productivity. A field experiment was conducted during the safflower growing season using a split-plot design with three replications to evaluate the effect of basal N levels and foliar application of nano urea on seed yield and economics. The treatments consisted of three basal N levels (100, 75, and 50% recommended dose of nitrogen, RDN) in main plots and five foliar sprays (no spray, nano urea at flowering, nano urea at flowering and seed filling, 2% urea at flowering, and 2% urea at flowering and seed filling) in sub-plots. Results revealed that application of 100% RDN recorded the highest seed yield (1507 kg/ha), with a 33.6% and 43.4% advantage over 75% and 50% RDN, respectively. Among foliar treatments, nano urea spray at flowering and seed filling (N2) produced the highest seed yield (1667 kg/ha), representing a 70.8% increase over the control. Economic analysis indicated maximum gross returns with N2 (₹92,567/ha). The interaction effects were generally non-significant, though F1N2 tended to outperform other combinations. The study demonstrates that nano urea foliar application, particularly at flowering and seed filling stages, enhances safflower productivity and profitability while improving nitrogen use efficiency. Integration of nano urea with reduced basal nitrogen offers scope for sustainable and resource-efficient nitrogen management in safflower.