Extra-Root topdressing of Sweet Potato

In the growth and development of sweet potato, it can be divided into three types: weak seedling, strong seedling and strong seedling. Extra-root topdressing must be carried out according to different appearance in order to make the seedling vine strong and the potato block high yield.

For weak seedlings, urea 05~1KG, calcium superphosphate 1~1.5KG, methyl sulfate 0.5 ~ 0.75KG per mu, mixed solution spray and 50~7KG per mu can be used to promote root development and stem and leaf growth.

Strong seedlings focus on spraying potassium and phosphorus on this kind of potato seedlings. Generally, potassium sulfate 1KG, calcium superphosphate 1KG, water 50-75KG per mu are used to make leaching mixture spray, or 10-20% plant ash leaching solution is sprayed, 50-75KG per mu.

The main task of applying fertilizer outside the root of this kind of potato seedlings is to restrain the growth and make it from prosperous to strong. It can be sprayed with 0.1% sulfamethoxazole, 50-75kg per mu once in 7-10 days, a total of 2-3 times.

For sweet potatoes in the later growth stage, foliar fertilizer can be sprayed as appropriate in order to prevent early senescence and enhance vitality. If premature leaf yellowing of potato seedlings is found, 50-75kg of 1% urea can be sprayed; for those with normal growth, 0.3% potassium dihydrogen phosphate fertilizer solution can be sprayed 1-2 times, 50-75KG per mu.