| 摘要 |
The present invention is directed to fertilizer additives and compositions, and to methods for their preparation and administration to plants. The fertilizer additives include chelated metal ions of the transition and alkaline earth metals. The chelated metal solutions are prepared by complexing metal cations using an organic acid and an organic amine. The fertilizer additives include a sufficient quantity of amine to maintain the pH above about 7.5 and preferably about 8-11. While the source of the metal ions may be any biologically acceptable metal salt, the metal oxides are preferred. The preferred chelating agents are citric acid and a difunctional amine. The preferred amines are 2-hydroxyethylamine, dimethylaminopropylamine and mixtures thereof. Additive solutions containing such chelated metals are stable at alkaline pH and are used to prepared clear, liquid fertilizer compositions for delivery of trace metals to plants.
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