The ratio of nitrogen, phosphorus, and potassium to yam during the whole growth period is 4: 1: 5, and the fertilizer requirements and types are different in different growth periods. Chinese yam is a chlorine-sensitive crop. Chlorine-containing fertilizers should be used with caution. It is not recommended to use medium-chlorine and above-chlorine fertilizers.

The growth period of yam is longer, and the amount of fertilizer required is large. The demand for medium and trace elements is relatively strict, especially the demand for calcium, boron, and zinc is relatively strong. Fertilization is generally based on base fertilizer, supplemented by top dressing.

Base fertilizer: 100-200 kg of organic fertilizer per mu plus nitrosulfur-based, potassium humate, pure sulfur-based or sprayed sulfur-based fertilizer balanced 40-50 kg plus 200 grams of granular zinc fertilizer and 200 grams of granular boron fertilizer.

Top dressing: During the tuber formation period, use 8-10 kg of nitro fertilizer or 3-5 kg of water soluble fertilizer with a large amount of balanced elements for 1-2 applications per mu.

During the period of rapid tuber expansion, use high-potassium compound fertilizers such as nitro fertilizer, sulfur-based or pure sulfur-based 50-100 kg furrow or hole application, or use high-potassium elemental water-soluble fertilizer 5-10 kg for 2-3 Times.

Foliar top dressing: In the period of tuber formation and tuber enlargement, combined with the prevention of plant diseases and insect pests, spray 0.2-0.3% potassium dihydrogen phosphate solution 2-3 times.