Efficient granular fertilizer containing alginic acid as well as preparation method of fertilizer

The invention relates to efficient granular fertilizer containing alginic acid. The efficient granular fertilizer comprises raw materials in parts by weight as follows: 50-400 parts of nitrogen fertilizer, 100-450 parts of phosphate fertilizer, 80-350 parts of potash fertilizer, 20-50 parts of clay, 10-20 parts of a microelement conditioner and 60-230 parts of a composite additive solution. A preparation method of the efficient granular fertilizer is simple to operate, and industrial production is facilitated; the prepared granular fertilizer has the characteristics of environment-friendliness, high efficiency, water retention, yield increase and the like, can effectively improve the soil quality, can save the production input cost, and is applicable to various crops such as soybeans, peanuts, corn, wheat, potatoes, sweet potatoes and the like.