Scientific fertilization method of yam

Yam seedling and vine stage mainly long branches and leaves, fertilizer mainly nitrogen, bud into the growth peak, underground tubers began to expand, fertilizer needs a large amount, is the key period of fertilization, nitrogen, phosphorus and potassium combined application. 1. Base fertilizer. Select the field, apply decomposed farm manure 2000 - 4000 kg and compound fertilizer 60 - 80 kg per mu as base fertilizer before ploughing, then plough the soil 30 cm and rake. Second, topdressing. Seedlings mainly nitrogen fertilizer, 10 kg-15 kg per mu of high nitrogen and potassium type compound fertilizer. In the first ten days of July, apply 20kg-25kg high nitrogen and potassium compound fertilizer per mu, and spray 0.25% potassium dihydrogen phosphate once. From late July, 0.25% potassium dihydrogen phosphate can be sprayed twice-3 times, and 20 kg-30 kg of nitrogen, phosphorus and potassium compound fertilizer per mu can be applied in early August. Tuber filling period generally do not take soil topdressing, can spray 0.25% potassium dihydrogen phosphate once, in order to extend the vine growth time.