What are the four key points of field management for sweet potato cultivation?

First is topdressing to promote seedling growth. Cultivate 7-10 days after planting; per mu, use 20-30 loads of human and livestock manure water mixed with 10-15 kg of ammonium bicarbonate or 5 kg of urea (preferably 7-10 kg of 40% high-efficiency compound fertilizer) to irrigate the planting holes; at the same time, per mu, apply 100-150 kg of plant ash mixed with 25-30 kg of superphosphate between the holes, do not apply it inside the holes (if high-efficiency compound fertilizer was used as base fertilizer, only use human and livestock manure water to promote seedling growth); when the vines and leaves close the rows, per mu, use 0.5 kg of 21.8% zinc sulfate or 0.8 kg of compound zinc fertilizer mixed with 50 kg of water for foliar spraying; in early October, per mu, use 100 g of potassium dihydrogen phosphate and 150 g of urea mixed with 50 kg of water for foliar spraying 2-3 times.

Second is pinching the tips to promote branching. When the sweet potato seedlings survive, remove all the seedling tips; this can shorten the vines, increase branching, increase green leaves, and improve plant shape, which is beneficial for forming more tubers. Note: do not turn the vines, and even more do not "prune the branch vines"; for excessively vigorous growth, you may arrange the vines and lift them to cut the fibrous roots and control excessive growth.

Third is draining waterlogging and preventing water damage. Clear the ditches and remove silt at all times, repair the ridge surface, and ensure there is no standing water in the furrows.

Fourth is timely harvesting. Dig and harvest sweet potatoes in early to mid-November; the tubers can be used for seed, food, or feed, the vine tips can be used as vegetables, and the vines and leaves can be ensiled as feed. Note: harvesting too early or too late will reduce yield, quality, and storability. Those marketed as fresh sweet potatoes may be dug and harvested appropriately earlier.