Effect of Foliar Application of Humic Acid and Nano-NPK on Some Growth Characteristic of Apple Trees Malus Domestica Borkh

Abstract

This study was carried out in one of the private orchards, which are 20 km away from Kirkuk province in the Altun Kobri area, during the period from May 2021 to August 2021, to study the effect of fertilizing with humic acid at three levels (0, 20, 40) gm and spraying with fertilizer The nano NPK with four levels (0, 1.5, 2.5, 3.5) g.L-1 in some growth characteristics and the yield of apple trees of the local Ibrahimi variety. The experiment was designed according to the design of randomized complete blocks (RCBD), a factorial investigation that included three factors of humic acid and four factors of the compound fertilizer nano NPK and with three replications, the number of treatments in each sector (12) treatments, and with 36 trees included in this experiment, and the treatments were distributed randomly on the experimental units, and for analyzing the data we use the SAS program, and the Duncan polynomial test was adopted under the probability level of 5%. The results showed that the humic acid fertilization gave significant differences in the averages of the studied traits, as the treatment of humic fertilizer at the level (40) gave the highest rate in the following characteristics (the chlorophyll content of the leaves and the proportion of potassium and phosphorous in the leaves). In contrast, the treatment (20) gave the highest rate in Characteristics (the percentage of nitrogen in leaves and leaf area). As for the treatment of spraying with nanocomposite fertilizer with a concentration of (3500), it achieved the highest rate in the characteristics (the content of chlorophyll in the leaves and the percentage of nitrogen, phosphorous and potassium in the leaves), while it gave the concentration (2500) the highest rate in the leaf area. The results also showed that the binary interaction achieved significant differences in the studied traits, as treatment (40) of humic fertilizer and (3500) of the nano-complex fertilizer achieved the highest rate in most of the studied features, namely (leaf area, leaf content of chlorophyll and phosphorous percentage in leaves).