The response of okra plants Abelmoschus esculentus (L) Moenth. Cultivated in greenhouses for foliar spraying with nano fertilizer NPK

The study was carried out during the winter season 2018-2019 under the conditions of unheated greenhouses of the Agricultural Research Station of the College of Agriculture-University of Muthanna, to study the effect of foliar application with nano NPK fertigation and the number of sprays on the chemical properties of the leaves and fruits of okra plants Hasinawi variety. The study included four concentrations of nano NPK fertilizer (0, 0.5, 1.0, 1.5) ml L −1 with number of sprays (once and twice) and interaction between them. Randomized Complete Block Design (RCBD) was used with three replicates per treatment. The means of treatment were compared by Least Significant Difference (L. S. D) at 0.05 probability. The aforementioned treatments and their interactions in the chemical properties of leaves and fruits were studied, which included leaf content of chlorophyll, carbohydrates, the percentage of total soluble solids (TSS) of fruits, the percentage of fibres, phenols, polyphenol oxidase (PPO) and the percentage of total protein, Results indicated that spray treatment with a concentration of 1.5 ml L −1 was superior in increasing the chlorophyll content, TSS and the percentage of fibers. Spraying twice treatment with nano NPK fertilizer outperformed all the chemical properties of the leaves and fruits under study. In the case of overlap between both factors, as the treatment of spraying with a concentration of 1.5 ml L −1 times was superior, with significant differences in most of the characteristics studied.