What fertilizer is best for sweet potatoes? A guide to controlling sweet potato vine growth

Sweet potato is one of the foods we often see in daily life, and this food has very high nutritional value and a delicious taste, and is loved by many people. But growing this food yourself really tests your skill and experience. Although sweet potatoes grow quickly, proper fertilization can make them grow even better.

What fertilizer is best for sweet potatoes

1. Base fertilizer

For sweet potatoes to yield high, you must apply sufficient base fertilizer, with base fertilizer as the main part and top dressing as the supplement. The base fertilizer should consist of fully decomposed organic fertilizer and an appropriate amount of chemical fertilizer. Generally, apply 2000 kg of high-quality decomposed farmyard manure (soil-and-manure mix of chicken manure, cow manure and horse manure), 50 kg of potassium sulfate compound fertilizer and 15 kg of superphosphate per mu.

Besides nitrogen, phosphorus and potassium, sulfur, iron, magnesium, calcium and others also play important roles. Among the three elements, sweet potato has the greatest demand for potassium, followed by nitrogen, and the least for phosphorus. Therefore, increasing potassium fertilizer and applying nitrogen and phosphorus fertilizer at the right time and in the right amount has a significant yield-increasing effect.

2. Top dressing

7 days after planting, apply seedling-strengthening fertilizer as top dressing, 5-8 kg of ammonium bicarbonate per mu. 1 month after planting, apply plant-strengthening fertilizer as top dressing; this top dressing provides nutrients for tuber enlargement, so the amount should be larger, with 80 kg of ammonium bicarbonate applied per mu. In addition, when growing sweet potatoes, pay attention to foliar top dressing, that is, spraying some leaf fertilizer, which you can mix yourself: dissolve 1.5 kg of urea and 0.5 kg of monopotassium phosphate in 100 kg of water to make a solution for spraying.

How to control the growth of sweet potato vines

1. Topping

The first time, when the main vine grows to 40 cm, remove the growing point of the main vine; the second time, when the branches grow to 30 cm, remove the growing points of the branches. In this way, the branches increase, the stems and leaves flourish, photosynthesis is enhanced, and the distance for transporting nutrients among roots, stems and leaves is shortened, thereby promoting tuber enlargement.

2. Lifting the vines

When the vines and leaves show excessive growth, lift them from the ground and then place them back in the original position, without twisting the stems and leaves, without disrupting the arrangement of the vines and leaves, and without breaking the vines and leaves. This can inhibit the formation of adventitious roots at the stem nodes and excessive growth of vines and leaves. Generally, lift the vines once every 10-15 days.

3. Spraying potassium

After the vines and leaves close the rows, use 500 g of monopotassium phosphate mixed with 100 kg of water per mu for foliar spraying, spraying once every 10 days for 2 consecutive sprayings. You can also use 15-20 kg of plant ash mixed with 50 kg of water, soak for 24 hours, then remove the residue and take the liquid, and spray it on a cloudy day or on a sunny afternoon, applying 50-60 kg of the extract liquid per mu. In this way, after spraying potassium, it can promote the activity of the root cambium and the synthesis and transport of carbohydrates, and can thicken the stems and leaves, thereby preventing excessive growth of vines and leaves and helping the tubers enlarge.

Sweet potato seedling-raising methods

1. Seedbed sowing: When raising seedlings from tubers, choose tubers of moderate size (a single tuber weighing 200-300 g is suitable), uniform and even, free of pests and diseases, free of wounds and free of cold damage as seed. The seedling bed is 1-1.2 m wide, and the length depends on need. Generally, every 50 kg of seed tubers can provide 0.9-15,000 seedlings, enough to plant 3-4 mu, with an average of about 10-25 kg of seed used per mu of field, and the sowing period should be about 100 days before planting.

2. Raising seedlings: When the seedlings grown from the seed tubers reach 25-30 cm in length, carry out temporary planting to multiply the seedlings, and when the number of nodes of the temporarily planted seedlings reaches 6-10 nodes, pinch off the growing tips to promote branching.

3. Fertilizing: 5-8 days before the planned seedling-collection period (before planting), apply a light application of quick-acting nitrogen fertilizer to cultivate tender and strong seedlings, and collect the seedlings in time for planting when the sweet potato seedlings reach 25-30 cm in length.

Cultivation and management of sweet potatoes

1. Adjusting light: Sweet potatoes like light. Under sufficient light, the leaves are darker in color, the leaf age is longer, the stems and vines are thick and strong, the conductive tissue of the stems is well developed, and the yield is higher. But sweet potato seedlings do not have very high requirements for sunlight, because the surrounding wall is always covered with plastic tarpaulin, and it is only uncovered later when the temperature is already high.

2. Controlling humidity: Sweet potato is a drought-tolerant crop, but too much or too little water is not good for increasing yield. The growth of sweet potato seedlings requires even better water control. If there is too little water, the sweet potatoes will be cooked by the excessively high temperature; if the humidity is too high, ventilate and expose them to the sun. In short, always observe the dryness and moisture of the soil and strictly keep it at about 50%.

3. Regulating temperature: The most suitable temperature for sweet potato seedling growth is 20-25 degrees. Below 20 degrees, increase the burning of firewood and cover well with plastic tarpaulin. Above 25 degrees, reduce the firewood, and you can also uncover the plastic tarpaulin to strengthen ventilation and cooling. Generally speaking, light the fire in early February, burning for about one hour in the morning and one hour in the evening each day, and after 15-20 days the fire can be stopped, as the effect of temperature is basically no longer significant.

Many times, people find that sweet potato seedlings grow very vigorously, but the sweet potato yield is not very high. This also tells everyone that properly tending the sweet potato vines during the growing period is very necessary, and may even increase the yield.