Preparation of Water-Soluble Chelated Iron(II) Compounds and Their Use as Microfertilizers. Influence of Solubility Promotors on the Structure of Spring Wheat Harvest under Foliar Treatment

Abstract

Microcrystalline poorly soluble iron(II) (1-hydroxyethylidene)diphosphonate hydrate FeH₂L·H₂O is obtained by the interaction of fine carbonyl or reduced iron(0) with (1-hydroxyethylidene)diphosphonic acid H₄L. At interacting with organic amines (monoethanolamine, tris(hydroxymethyl)aminomethane, 1,8-diamino-3,6-dioxooctane, morpholine) FeH₂L·H₂O turns into a water-soluble form, giving amorphous amine derivatives of FeH₂L·H₂NCH₂CH₂OH, FeH₂L·H₂NC(CH₂OH)₃, FeH₂L·H₂NCH₂CH₂OCH₂CH₂OCH₂CH₂NH₂, FeH₂L·HN(CH₂CH₂)₂O. Solutions of aminium compounds were used to determine their effect on the structure of the harvest of spring wheat under foliar treatment. Evaluating the effectiveness of foliar treatment with iron chelate compounds on the structure of the spring wheat harvest showed that the morpholinium iron chelate, FeH₂L·HN(CH₂CH₂)₂O, had the greatest impact, increasing the number of grains per ear up to 45.1 pcs. (control 38.8), the mass of grain from a plant up to 1.72 g (control 1.45), and the weight of an ear up to 2.18 g (control 1.90). The most significant change in the length of the ear was facilitated by the experiment with a solution of the monoethanolamine compound, FeH₂L·H₂NCH₂CH₂OH: increase of 0,57 cm relative to the control. The composition and structure of the iron(II) (1-hydroxyethylidene)diphosphonate hydrate FeH₂L·H₂O and its aminium derivatives were studied by IR spectroscopy, X-ray phase analysis and scanning electron microscopy.