Detailed Explanation of Foliar Fertilization Methods for Sweet Potato Cultivation

During its growth, the sweet potato can be divided into three types: weak seedlings, strong seedlings, and vigorous seedlings. Foliar fertilization must be carried out in a targeted manner according to the different growth appearances, in order to promote robust vines and high tuber yields.

For weak seedlings in such fields, 0.5-1 kg of urea, 1-1.5 kg of superphosphate, and 0.5-0.75 kg of potassium sulfate can be mixed into a soaking solution and sprayed per mu, with a spray volume of 50-7 kg per mu, to promote root development and stem and leaf growth.   

For strong seedlings, the focus for such potato seedlings is spraying potassium, while also spraying phosphorus. Generally, 1 kg of potassium sulfate and 1 kg of superphosphate are added to 50-75 kg of water to make a leaching mixed solution for spraying; or a 10-20% wood ash leaching solution is sprayed, 50-75 kg per mu.

For vigorous seedlings, the main task of foliar fertilization for such potato seedlings is to inhibit excessive growth and make them change from vigorous to strong. A 0.1% chlormequat solution can be sprayed, 50-75 kg per mu, once every 7-10 days, for a total of 2-3 sprays.

For sweet potatoes in the late growth stage, in order to prevent fertilizer deficiency and premature aging and to enhance vigor, foliar fertilizer can be supplemented as appropriate. If the potato vines are found to have yellowed and fallen leaves prematurely, a 1% urea solution can be sprayed at 50-75 kg; for those growing normally, a 0.3% monopotassium phosphate fertilizer solution can be sprayed 1-2 times, 50-75 kg per mu.