Combined foliar application of urea and potassium humate on nursery performance of guava cv. Sardar (L-49)

The production of vigorous and healthy nursery plants is fundamental for successful guava cultivation, as seedling quality directly influences field establishment, early growth and long-term orchard productivity. This study assessed the impact of foliar application of urea (1.0% and 1.5%) and potassium humate (1.0% and 2.0%), both applied separately and in combination, on the growth, root development, physiological characteristics, nutrient absorption and nursery performance of guava cv. Sardar (L-49) for two consecutive years. The experiment included eight treatments along with a control, organized in a Randomized Block Design with three replications and the effects of the treatments were evaluated using analysis of variance. The significant treatment effects were observed for all evaluated parameters. Among the treatments, the combined application of 1.5% urea + 2.0% potassium humate (KHm) consistently produced the best nursery performance, recording the highest plant height (51.90 cm), stem girth (1.10 cm), leaf area (25.15 cm 2 ), number of leaves (26.12), shoot number (5.42), root number (22.35), root length (9.87 cm), root volume (3.87 cm 2 ), root fresh weight (1.45 g) and root dry weight (0.41 g). The same treatment also resulted in the highest chlorophyll ( a , b and total chlorophyll) and leaf nitrogen, phosphorus and potassium contents, leading to maximum seedling survival (88.70%) and buddable seedlings (85.03%). Multivariate analyses, including principal component analysis, hierarchical clustering, correlation and regression, revealed strong positive associations among growth, root, physiological, nutrient and nursery performance traits, with the combined treatments clearly separated from the individual applications and untreated control. Overall, the integrated foliar application of 1.5% urea and 2.0% potassium humate (KHm) proved to be the most effective strategy for improving seedling vigour, root development and production of high-quality buddable nursery plants, providing a practical nutrient management approach for commercial guava nursery production.