DEVELOPMENT OF BORON-MODIFIED AMINOPLAST RESIN COATINGS FOR ENHANCED UREASE INHIBITION IN SALINE-SODIC SOILS

The melamine-formaldehyde-boron (MFB) composite was synthesized with high efficiency, achieving a 95% yield. The incorporation of boric acid into the melamine-formaldehyde resin matrix resulted in a homogeneous, physically stable polymer composite. The synthesis was characterized by FT-IR spectroscopy, revealing key functional groups such as N-H stretching (~3350 cm⁻¹) for melamine residues, C=O stretching (~1650 cm⁻¹) for formaldehyde, B-O vibrations (~1350 cm⁻¹) for boric acid integration, and C-N bending (~1250 cm⁻¹) indicative of cross-linking between melamine, formaldehyde, and boric acid. Further investigations evaluated the impact of boric acid-coated urea granules on the productivity and physicochemical properties of saline-sodic soil. Boric acid incorporation (5% coating) significantly improved soil conditions by lowering pH, reducing electrical conductivity, and increasing organic matter content. Moreover, urease activity was reduced by 75%, leading to improved nitrogen retention. The effect of boric acid on plant productivity was most pronounced at a 5% coating, with radish plant productivity showing a 44% increase, along with improvements in shoot and root biomass. These findings highlight the potential of MFB-coated urea granules to enhance soil health and plant growth, demonstrating the effectiveness of boric acid in optimizing nitrogen release and mitigating soil salinity.