It is necessary to increase the yield of sweet potato and pay attention to 5 points in the later stage.

After late August, the summer sweet potato enters the critical period of expansion, at this time, the management should be strengthened, on the one hand, to maximize the nutrients needed for the expansion of sweet potato, on the other hand, to prevent premature senescence of stems and leaves, enhance photosynthesis and increase nutrient accumulation. The specific technical suggestions for increasing production are as follows:

1. Take off the top

The topping heart can regulate the movement of nutrients and promote the transport of nutrients to the root tuber. Peeling the top was carried out twice, the first time when the potato vine grew to 30 cm long and 40 cm long, the first time when the branch grew to about 30 cm long, and the second time when the branch grew to about 30 cm, the tender tip was removed.

2. Pruning

For potato fields with more branches and more prosperous growth, 2-3 branches can be cut off with scissors, so that nutrients can be returned, potato pieces can get more nutrients, light transmission between potato branches and potatoes can be improved, photosynthesis can be accelerated and so on. But the poor soil is not suitable to pick the heart.

3. Increase the application of potash fertilizer

After sealing the ridges of potato seedlings in August, potassium dihydrogen sulfate solution can be sprayed, that is, potassium dihydrogen sulfate solution is prepared into 1: 2% solution of potassium dihydrogen sulfate to water, spraying 50-70 kg per mu, once every 5-7 days for 3 times, and spraying 50-70 kg per mu for fields with insufficient base fertilizer, thin stems and leaves, or fattening in the later stage, using 0.3% potassium dihydrogen phosphate solution plus 0.5% urea fertilizer solution. Spray once every 5 or 7 days, 2 times in a row.

4. Lift the vine

The method of lifting vines can be used to prevent excessive root loss in overgrown potato fields. If the sweet potato grows too much after sealing the ridge, you can gently lift the potato vine and put it back in the same place. The time to lift the vine should be controlled before the end of August, for a total of 2 or 3 times.

5. Topdressing crack fertilizer

The time of topdressing crack fertilizer is generally 70 ~ 80 days after planting, when the potato pieces enter the peak period of expansion, and when cracks appear on the border surface. The details should be determined according to the growth and soil quality of summer sweet potatoes. For example, the fields with insufficient fertilizer, thin soil layer and poor plant growth can be applied early, and the amount of topdressing can be 800~l000 kg of rotten human and animal manure per mu, or 7kg of urea to 600kg of water. If the fields with sufficient fertilizer and exuberant plant growth in the early stage, they can apply less or only soil miscellaneous fertilizer and potash fertilizer, but not nitrogen fertilizer.