Growth and yield response of sunflower to varied nitrogen levels and foliar nano urea and zinc applications

Abstract

A field experiment was conducted at the Agricultural and Horticultural Research Station, Bavikere (Karnataka), during the rabi season of 2021-22, to investigate the effects of varied nitrogen levels and foliar applications of nano urea and zinc on the growth and yield of sunflower under irrigation conditions. The study employed a randomized complete block design (RCBD) with a factorial concept, replicated three times. The treatments comprised three factors: nitrogen levels, frequency of nano urea sprays, and zinc spray concentrations. The results revealed that applying 125% of the recommended dose of nitrogen (RDN) significantly enhanced sunflower growth, yield attributes and seed yield (2174 kg ha-1), with no significant difference compared to 100% RDN. Foliar applications of nano urea at 0.4% concentration, administered twice, demonstrated superior growth, yield parameters and seed yield (2074 kg ha-1). Conversely, varying zinc spray concentrations did not exhibit substantial differences in sunflower growth and yield. Notably, the interaction effects of the three factors revealed that the combination of 125% RDN, two nano urea sprays at 0.4%, and 1% zinc spray yielded the highest growth, yield parameters and seed yield (2265 kg ha-1). This optimal treatment combination was statistically comparable to applying 125% RDN, two nano urea sprays at 0.4%, and 0.5% zinc spray. These findings suggest that optimized nitrogen levels and nano urea applications can significantly improve sunflower productivity, while zinc spray concentrations may have minimal impact. The study's outcomes have important implications for developing efficient nutrient management strategies to enhance sunflower yields under irrigated conditions.