After July, high temperature and high humidity will benefit the great growth of sweet potatoes making them very vigorous. When entering the stage of potato vines, it is at the right time of a rainy season when sweet potatoes' stems and leaves reach the peak period of growing. There are four points for long-term management in growing period of sweet potatoes:
1. Lifting vines and topping
It is better to apply the way of lifting vines rather than the traditional one of mixing vines because the traditional one is more likely to damage stems and leaves, affect the regular growing process of sweet potatoes, and consequently influence the output, while lifting vines causes less damage. When the main stems are about 50 cm, the top buds should be removed to inhibit growth; when the branch is about 35 cm, some of the top buds need to be removed.
Lifting vines can prevent the formation of sweet potatoes breaking out into fine roots. Topping can inhibit some vain stems and leaves and avoid nutrient consumption, which is conducive to the growth of roots and thereby increase yield.
2. Cultivating roots and contol the growth of vines
A field of one mu(6.67 acres) needs to be sprayedd with fertilizers mixing up 80-100 grams of mepidol and 30 kg of water, or 80 grams of paclobutrazol and 30 kg of water. Generally, it can effectively prevent the madness of potatoes for two or three times. Sweet potato bulking agent can be used for foliar spraying, which can be helpful to promote tuber swelling. It can be sprayed once every ten days or so, and totally it will take two times. If permitted, spraying with multi-element micro fertilizers such as 0.5% potassium dihydrogen phosphate can be more effective for better growth.
3. Irrigating and draining
Although sweet potatoes are knid of plants resistent to drought, they also need to be watered if it is dry for really a long time. And it is allowed to irrigate sweet potatoes once every 10 days. When it happens to heavy rain, it would be necessary for those plants to drain rainwater as soon as possible, or the roots are much more likely to be rotted and decayed.
4. Protecting plants away from pests
Sweet potatoes' vines suffer from pests much more likely mainly including leaf curlers, spodoptera litura, and sweet potato hawk moth and so on. These can be killed in the evening before the third instar of the larva.
Please stick to these four points of field management in this period of time. And it will not be a long time for high yield of sweet potatoes.