Slow fertilizer and preparation method thereof

The invention provides a slow fertilizer and a preparation method thereof. The slow fertilizer is prepared from the following raw materials in parts by mass: 10 to 40 parts of composite polyphosphate, 10 to 35 parts of urea, 10 to 35 parts of potassium fertilizer, 0.2 to 2 parts of a nitrogen synergist, 0.5 to 2 parts of a stress-resistant agent, 0.002 to 0.008 part of a soil activator, 0.05 to 2 parts of trace elements and 0.02 to 0.05 part of auxiliary materials, the composite polyphosphate is a mixture of ammonium polyphosphate and magnesium calcium polyphosphate; the nitrogen synergist is a mixture of a nitrification inhibitor and a urease inhibitor; the soil activator is a resuscitation promoting factor Rpf protein. The slow fertilizer provided by the invention can reduce the loss of nitrogen and phosphorus, improve the utilization rate of nitrogen and phosphorus, and effectively improve the micro-ecological environment of soil. 本发明提供了一种慢肥及其制备方法。该慢肥由以下质量份的原料组成：复合聚磷酸盐10-40份、尿素10-35份、钾肥10-35份、氮素增效剂0.2-2份、抗