| 摘要 |
A granular fertilizer is rendered slow release by a coating of a water-insoluble synthetic resin containing a metal, oxide, salt, or swellable organic substance in an amount of up to 50% of the total coating. The coating may constitute 2-20% of the product. The resin may be vinyl/vinylidene chloride, vinyl chloride/methyl acrylate or drying oil/cyclopentadiene copolymer. The metal may be iron, zinc, magnesium, copper, or aluminium; the oxide may be silica; the salt may be ammonium, potassium, or calcium sulphate; and the swellable organic substance may be gelatine or a -methyl cellulose. The metal, oxide, or salt may have a particle size of 4-60m . The resin may be applied as a solution or aqueous emulsion. The additional substance may be added together with or separately from the resin. |
