Distribution of sweet potatoes

Sweet potato is an annual herbaceous vine of the sweet potato family. Historical facts have proved that sweet potato was introduced into Fujian and Guangdong in China from Nanyang at the end of the 16th century, and then spread to the Yangtze River, Yellow River valley and Taiwan Province. Today, China's sweet potato planting area and total output are the largest in the world. Let's take a look at the distribution of sweet potatoes.

World Distribution of Sweet Potato

The sweet potato world is distributed in South America, the Greater Antilles and the lesser Antilles, and in the tropics and subtropics of the world (mainly in the south of 40 °N).

Distribution of sweet potato in China

Sweet potatoes are mainly distributed in Beijing, Shanxi, Shandong, Henan, Tianjin, Hebei and East China, Inner Mongolia, Yunnan, Sichuan, Hubei, Gansu, Anhui, Fujian, Shaanxi, Hunan, Guangdong, Jiangsu and Jiangxi. The main producing areas in China are Anhui Si County (the hometown of Chinese yams), Hebei Lulong, Fujian Liancheng, Henan Kaifeng, Dengzhou, Tanghe Tongzhaipu, Shandong Sishui, Sichuan Nanchong and so on.

Environment of producing area of sweet potato

1. Temperature: sweet potato likes warm and cold, and the ground temperature is about 10 ℃. It takes 5 days for 15 ℃, normal for 17-18 ℃, 3-day for 20 ℃, and one day for 27-30 ℃. When the temperature is 25-28 ℃, the stem and leaf grow faster, but the potato expands slowly when the temperature is above 30 ℃. The respiratory consumption was more than 38 ℃, and the stem and leaf grew slowly. The stem and leaf grew fast when the temperature was below 20 ℃, and stopped growing at 15 ℃. The duration below 10 ℃ became frost, and the stem and leaf withered.

2. Light: sweet potato likes light. Under the condition of sufficient light, the leaf color is thicker, the leaf age is longer, the stem is sturdy, the stem transport tissue is developed, and the yield is higher. If the light is insufficient, the leaves are yellow, the leaves are more deciduous, the leaf age is short, the stem is slender, the transport tissue is underdeveloped, the organic nutrients formed by assimilation are less transported to the root tuber and the yield is low.

3. Moisture: sweet potato is a drought-tolerant crop, but too much and too little moisture is not conducive to yield increase. Sweet potato is afraid of flooding, especially after fruiting, it has a great impact on the yield. The unbalanced growth rate of tuber inside and outside of the soil caused by the uncertainty of soil dryness and humidity often leads to the phenomenon of bark cracking. In short, sweet potatoes are afraid of both waterlogging and drought. The masses say, "dry long firewood roots, wet long whisker roots, non-dry and wet long roots." In order to obtain high yield of sweet potato, we should timely and properly irrigate according to specific conditions, drain waterlogging in time and thoroughly, and strengthen ploughing and preserving soil moisture in dry land.

4. Nutrients: sweet potato has strong fertilizer absorption ability and resistance to barren, but sufficient fertilizer must be applied for high yield. in addition to nitrogen, phosphorus and potassium, sulfur, iron, magnesium and calcium also play an important role. among the three elements, sweet potato has the most requirements for potassium, followed by nitrogen and phosphorus. According to the analysis, every 1000 jin of sweet potato contains 3.5jin of nitrogen, 1.75jin of phosphorus and 5.6jin of potassium. Therefore, increasing the application of potassium fertilizer, timely and appropriate amount of nitrogen and phosphorus fertilizer can significantly increase the yield.

5. Soil: it is better for sandy loam and sandy soil with rich organic matter, loose, aerated and good drainage in deep soil layer. when the soil is sticky and heavy, the skin color of root tuber is not good, rough, irregular potato shape, low yield and not resistant to storage. However, sandy loam and sandy soil generally have low fertility and poor water retention, so fertilization and other measures should be adopted to gradually improve soil fertility in order to obtain high yield. Sweet potato is more resistant to acid and alkali, and the range of pH value is about 4.5 to 8.5, but 5.2 to 6.7 is suitable. When the soil salt content is more than 0.2%, it is not suitable to plant sweet potato.