SOFT ORGANOMODIFICATION OF BENTONITE WITH OXYPHOSPHONATE AND ITS APPLICATION AS A PROLONGED-LASTING GROWTH STIMULATOR

Abstract

Introduction. Organomodified clay materials are of significant interest as functional systems for agriculture due to their ability to provide the sustained release of biologically active substances. Natural bentonite, with its high specific surface area and ion-exchange capacity, serves as an excellent matrix for the immobilization of organic growth stimulants. The purpose of this study is to develop a low-energy, efficient method for the soft organomodification of bentonite using a specific oxyphosphonate (Kaz-6) and to evaluate its effectiveness as a prolonged-action growth stimulator for wheat. The proposed method involves the pre-dispersion of bentonite in water at 40°C, followed by drying at 50°C. The prepared mineral matrix was then treated with low-concentration aqueous solutions of dimethyl(4-hydroxy-1-(2-ethoxyethyl)piperidin-4-yl)phosphonate (Kaz-6) in the concentration range of 10^-2–10^-6 wt % at room temperature. The structure of the resulting composite was characterized using IR spectroscopy. It was found that the developed approach significantly reduces the process temperature and duration compared to existing analogs, while using substantially lower concentrations of the organic component. Biological trials showed that the organomodified bentonite exhibits pronounced growth-promoting activity toward wheat (varieties “Almaken” and “Zhenis”). The most significant stimulatory effect was observed at concentrations of 10^-5–10^-6 wt. %, where the composite outperformed both the control group and the free (unbound) oxyphosphonate. The results indicate that the immobilization of Kaz-6 on bentonite ensures prolonged action and increased bioavailability of the active component. The developed organomineral composite can be recommended as a promising growth-promoting agent for sustainable agricultural applications.