How to fertilize sweet potato growing period?

How to fertilize sweet potato growing period? Please guide in sweet potato late growth, reasonable fertilization can prevent premature senescence of plants, maintain the assimilation ability of leaves, promote nutrient transport to the root tuber, thus increasing yield. Foliar fertilizer spraying sweet potato into the late growth, root absorption capacity weakened, can be classified foliar fertilizer spraying. 0.5% urea solution can be sprayed on hilly slope, plain sand or field with premature senescence tendency, 0.2% potassium dihydrogen phosphate solution or 2%~3% calcium superphosphate leaching solution can be sprayed on field with vigorous growth and high fertility level. For general fields, 0.4%~0.5% urea and potassium dihydrogen phosphate mixed solution can be sprayed once every 7~10 days, spraying 2~3 times in total, spraying 70~100 kg fertilizer solution per mu each time, spraying time is appropriate in the evening of sunny day. Fertilizer irrigation with 3%~5% potassium sulfate solution or 10%~20% plant ash leaching solution along the ridge irrigation, fertilizer solution 100~150 kg per mu. For the field with premature senescence tendency, 2% ternary compound fertilizer solution can be applied. Click for more sweet potato planting technology Click for more vegetable planting technology