EFFECT OF CHEMICAL NITROGEN FERTILIZER LEVEL AND HUMIC ACID RATE ON Gladiolus grandiflorus PRODUCTIVITY

Abstract

during two successive seasons 2017-2018 and 2018-2019 to study the effect of various levels of nitrogen fertilizer (0, 100, 200 and 300 kg fed -1 ) in combination with different rates of humic acid (0, 150, 250 and 350 ppm) as a foliar spray on plant growth, flowering characteristics, corms and cormels characteristics and chemical constituents. The obtained results cleared that using 200 kg fed -1 nitrogen in urea forms with 350 mgl -1 humic acid as a foliar spray gave the maximum value in each of vegetative growth parameters, flowering characteristics, diameter of corms, weight of cormel, and chemical constituents (N, P and K) content in leaves. However, a non-significant variation was observed in the treatment 200 kg fed -1 nitrogen with the three concentrations of humic acid for weight of corms and No. of cormels in plants in most cases. While, plants grown without nitrogen and humic acid (control) gave the minimum values in all parameters.Humic acid is a natural organic polimar composition produced as a result of decaying organic matter, peat as well as lignin, and so that can be used to increase productivity and its quality (Valdrighi et al., 1996). The positive effects are directly on the plant growth and improve the growth of shoots and roots, absorpotion of nitrogen, calcium, potassium, magnesium and phosphorus by plant (Haghighi et al., 2011). The application of humic acid

Impact of Foliar Fertilization on Growth, Flowering, and Corms Production of Five Gladiolus Varieties

“…Foliar fertilization was more effective and significantly enhanced the shoot and flower stem growth compared to the control plants. Similar to our study, some researchers reported that foliar fertilization promoted the flower stem growth to the maximum levels in gladioli, which could have a constructive role in the development of the flowers [ 15 , 19 , 20 ]. Similar findings have been described where the administration of foliar fertilization treatments influenced the Calendula inflorescence yield, but not the chlorophyll parameters, where no significant differences were observed between the treatments [ 21 , 22 ].…”