"Longevity food" sweet potato: what temperature is suitable for its growth? Which cultivation and management techniques must be mastered to achieve high yields?

Sweet potato, also known as taro, red taro, sweet potato, fan shu, fan yu, and di gua (in the north), is rich in protein, starch, pectin, cellulose, amino acids, vitamins and various minerals, and has the reputation of being a "longevity food." Today, China's sweet potato planting area and total output both rank first in the world. What temperature is suitable for sweet potato growth? Which cultivation and management techniques must be mastered to achieve high yields?

I. Effects and functions of sweet potato

1. Anti-cancer effect

The nutrients with the strongest anti-cancer effects in the diet are β-carotene (a precursor of vitamin A), vitamin C and folic acid, which help maintain normal folate levels in the human body, while too low a folate content in the body increases the risk of cancer. The high content of dietary fiber in sweet potato promotes gastrointestinal motility and helps prevent constipation and colorectal cancer.

2. Beneficial to the heart

Sweet potato is rich in potassium, β-carotene, folic acid, vitamin C and vitamin B6, and all five of these components help prevent cardiovascular disease. Supplementing folic acid and vitamin B6 helps lower blood homocysteine levels, and the latter can damage arterial blood vessels and is an independent risk factor for cardiovascular disease.

3. Preventing emphysema

Sweet potato is rich in vitamin A, and American researchers suggest that smokers or those exposed to secondhand smoke should preferably eat some vitamin A-rich foods such as sweet potato every day to prevent emphysema.

4. Weight loss and slimming

Sweet potato is rich in dietary fiber, and after entering the intestinal tract it can clear waste from the intestinal canal, gather toxins and waste together, and help expel them smoothly from the body. Sweet potato can also create new cells in the intestine and promote metabolism.

5. Enhancing immune function

Sweet potato contains a large amount of mucin, which can prevent atrophy of the connective tissue of the liver and kidneys, improve body immunity, and prevent the occurrence of collagen disease. Sweet potato also contains calcium and magnesium, which can prevent osteoporosis.

6. Sweet potato can also inhibit skin aging, maintain skin elasticity, and slow the body's aging process.

II. What temperature is suitable for sweet potato growth?

Sweet potato likes warmth and fears cold. At 17-18°C rooting is normal, at 20°C roots form in 3 days, and at 27-30°C roots can form in just one day; when the temperature is 25-28°C the stems and leaves grow quickly; a soil temperature of 22-24°C is more favorable for the formation of storage roots.

III. High-yield cultivation and management techniques for sweet potato

1. Cultivating strong seedlings

The high-yield performance of sweet potato varieties and the quality of the potato seedlings are the internal factors that determine yield. Virus-free, disease-free strong seedlings can pass on excellent genes and keep the offspring with excellent traits as well.

When planting, choose virus-free, robust potato seedlings as much as possible. Therefore, doing a good job of raising seedlings from storage roots, improving seedling quality, and purifying and rejuvenating variety characteristics can significantly increase sweet potato yield.

2. Choosing soil

Sweet potato is not very strict about soil requirements, but it prefers light loam or sandy loam with deep, loose soil, good drainage, rich organic matter and good fertility conditions. This type of soil is loose and breathable, and the storage roots are slender and neat, with bright skin color, good eating quality, high dry matter rate and good storage tolerance.

However, the drawback is poor water and fertilizer retention, making it prone to drought and nutrient deficiency. Field management measures such as increased fertilization and irrigation (drip irrigation with water and fertilizer, foliar fertilization, etc.) are needed to obtain high yields.

3. Timely planting

Sweet potato is a warmth-loving crop. The optimum temperature for storage root formation is 24-25°C, and the optimum temperature for storage root enlargement is 22-24°C. According to the conditions required for sweet potato growth and development and the local climate characteristics, seize the season and plant around “Major Heat” so that in the early stage the sweet potato can make full use of the high temperature and strong light conditions of July-August, grow stems and leaves in time, branch early, form storage roots early, and form many storage roots.

January is the month with the lowest temperatures, which is unfavorable for sweet potato growth and development and may even cause freezing damage. Therefore, it is necessary to master timely early planting, strive for early storage root formation and early enlargement, and extend the effective enlargement period of the storage roots, so as to achieve high sweet potato yields.

4. Horizontal shallow planting with sufficient seedlings

The planting density and planting method of sweet potato also have a certain influence on yield. It should not be too sparse, nor too dense. If too dense, photosynthesis will be affected and the plants will not grow well; if too sparse, it not only wastes soil but also easily breeds weeds, diseases and insect pests, affecting sweet potato growth.

Generally, plant 3800-4000 plants per mu, using the method of single-row planting on high, fine ridges with horizontal shallow planting. Build trapezoidal ridges 90 cm wide (including the ditch) and 36 cm high, with a plant spacing of 17 cm, plant horizontally and shallowly at 2-3 cm, and water the planting holes in time and cover with soil. It is recommended to cut seedlings at noon on a sunny day and plant in the afternoon, trying to harvest seedlings the same day and plant them the same day to ensure the survival rate.

5. Reasonable fertilization and water

For autumn sweet potato, the principle of “light at the front, heavy in the middle, supplementary at the end” should be followed, mainly using organic fertilizer and supplementing with chemical fertilizer, applying frequently and lightly.