| 摘要 |
<PICT:1011463/C1/1> A slow release fertilizer is in the form of agglomerates or extruded pellets containing 2-25% of a water-repellent binder. The binder may be asphalt having a softening point above 120 DEG F., paraffin wax, natural rubber, polyethylene, polypropylene, polystyrene, polybutadiene, polyvinyl resin, or petroleum resin. The binder may be mixed with the fertilizer in the molten state or dissolved in a volatile solvent; or may be formed in situ by polymerizing drying oil or butadiene. Up to 50% of a filler may be added before or after incorporation of the binder. The filler may be chalk, limestone, calcined lime, gypsum, clay, or phosphate rock. A number of pellets having a diameter of 1/16 to 1/2 inch may be bound together with additional binder to form a larger pellet (Fig. 4). The additional binder may contain additional fertilizer and/or filler. The fertilizer may be a mixture of ammonium sulphate, potassium chloride and dicalcium phosphate. |
