Catalog
1.Growth habit
2.Morphological characteristics
3.Geographic distribution
4.Cultivation techniques
5.Nutritional value
1.Growth habit
Growth period
Spring potatoes grow in 160-200 days, and summer potatoes in about 110-120 days. 120 days, according to the growth characteristics of red spring in the field and its relationship with the climate conditions, roughly divided into three growth periods:
(a) Pre-planting (from planting seedlings to sealing pots). Spring potatoes last about 60-70 days, summer potatoes about 40 days. The period of slower stem and leaf growth, faster root development, is the period of growth of fiber roots mainly.
(ii) the middle period (closed pot to the peak of stem and leaf growth). Spring potatoes last about 50 days, summer potatoes about 30 days. The period of tuber expansion slower, stem and leaf growth fast, is to grow stem and leaf-oriented period.
(iii) Late stage (from the beginning of stem and leaf decline to harvest). Spring potatoes after late August, summer potatoes after early September. This period is the main period of tuber expansion.
Growing environment
(I) Temperature. Sweet potato likes temperature and fear of cold, planting seedlings 5-10 cm, ground temperature at about 10 ℃ does not root, 15 ℃ need 5 days to root, 17-18 ℃ root normal, 20 ℃ 3 days to root, 27-30 ℃ only one day to root.
Temperature 25-28 ℃ when the stem and leaf growth fast, 30 ℃ above the stem and leaf growth faster, but slow expansion of potatoes. 38 ℃ above the respiratory consumption, stem and leaf growth slow, 20 ℃ below the stem and leaf growth is also fast, 15 ℃ when the growth stops, 10 ℃ below the duration is too long into the case of frost, the stem and leaf withered.
The higher the ground temperature between 21-29 ℃, the faster the formation of tuberous roots, the more, but smaller potatoes. 22-24 ℃ of the ground temperature is more conducive to the formation of tuberous roots. 20-25 ℃ of the ground temperature is best suited to tuberous root expansion, lower than 20 ℃ or higher than 30 ℃ expansion slower, lower than 18 ℃ varieties to stop the expansion of lower than 10 ℃ susceptible to cold, at -2 ℃ when the tuberous roots are frozen. Tuber expansion during the larger day and night temperature difference is conducive to tuber expansion and nutrient accumulation.
(ii) Light. Sweet potato likes light, in the case of sufficient light, the leaf color is thicker, the leaf age is longer, the stem is thick and sturdy, the stem's conduction tissue is developed, and the yield is higher. If the light is insufficient, the leaf color is yellowish, the leaf drop is more, the leaf age is short, the stem trailing is slender, the conduction tissue is not developed, the organic nutrition formed by assimilation is less transported to the tuberous root, and the yield is low.
Long daily exposure to light is favorable to the growth of stem and leaves, the stem and vine become longer, and the number of branches increases. 12.5-13 hours of light per day is better for root expansion. 8-9 hours of light per day is favorable for buds and flowers, but not suitable for root expansion.
(iii) Water. Sweet potato is a drought-resistant crop, however, too much water is not conducive to yield. Sweet potato is afraid of flooding, especially in the potato after flooding on the yield impact is great. Soil dry and wet uncertainty caused by tuber inside and outside the growth rate is not balanced, often cracked skin phenomenon. In short, sweet potato is afraid of flooding, and afraid of drought, the masses say: dry long faggots, wet long fibrous roots, not dry and not wet long tubers. To get a high yield of sweet potato, according to the specific conditions should be timely and appropriate amount of irrigation, timely and thorough flooding, dry land to strengthen the plow to preserve moisture.
(iv) Nutrients. Sweet potato absorb fertilizer capacity, barren, but to high yield must apply enough fertilizer. In addition to nitrogen, phosphorus, potassium, sulfur, iron, magnesium, calcium and other important role. In the three elements of the sweet potato on potassium requirements of the most, followed by nitrogen, phosphorus least. According to the analysis, every 1000 pounds of sweet potato contains 3.5 pounds of nitrogen, phosphorus 1.75 pounds, potassium 5.6 pounds. Therefore, increase the application of potash fertilizer, timely and appropriate application of nitrogen and phosphorus fertilizer has a significant increase in yield.
(E) soil. To deep soil, rich in organic matter, loose, aeration, good drainage performance of sandy loam and sandy soil is good. When the soil is sticky, the tuber skin color is not good, rough, the potato shape is not neat, low yield, intolerant of storage. However, sandy loam and sandy soil generally have low fertility, poor water retention, and should be gradually fertilized through fertilization and other measures to obtain high yield. Sweet potato is more resistant to acid and alkali, adapting to the PH value range of about 4.5-8.5, but 5.2-6.7 is preferable. When the soil salinity exceeds 0.2%, sweet potato should not be planted.
2. Morphological characteristics
Root
Annual herb, the underground part is round, oval or fusiform tuberous root, the shape, skin color and flesh color of the tuberous root vary according to varieties or soil. The stem is procumbent or ascending, occasionally twining, much branched, cylindrical or momentous, green or purple, sparsely pilose or glabrous, and the nodes of the stem are prone to produce adventitious roots.
(1) Fiber root, also known as fine root, is fibrous, thin and long, with many branches and root hairs, with the function of absorbing water and nutrients. Fiber roots grow rapidly in the pre-growth period, the distribution is shallow; late growth is slow, and to the depth of the development. Fiber roots are mainly distributed in the 30 cm deep soil layer, a few deeper than 1 meter.
(2) Shiba root, also known as thick root, stalk root, burdock root, root length 0.3-1 meters, 0.2-2 meters thick. Shiba root is due to the influence of adverse climatic conditions (such as low temperature and rain) and soil conditions (such as nitrogen fertilizer applied too much, and phosphorus, potassium fertilizer applied too little), so that the organization within the root changes. It is formed by stopping thickening in the middle of the process. Chai root in vain nutrient consumption, no use value, should be prevented from occurring.
(3) Tubers, also called storage roots, are a perversion of roots. It is the potato tuber for people to eat and process. Sweet potato tuberous root is both storage nutrient organ and important reproductive organ. Tubers are thicker adventitious roots on the trailing joints, grown in the same period of good soil, fertilizer, water, temperature and other suitable conditions. Sweet potato tuberous roots grow in the 5-25 cm deep soil layer, rarely occur in the soil layer below 30 cm. The number of potatoes produced by a single plant, the size of potatoes, and the characteristics of varieties and cultivation conditions are related. Tubers usually have fusiform, round, cylindrical, blocky and other shapes. Although the shape of tuber is a variety characteristic, it also changes with soil and cultivation conditions. The skin color is white, yellow, red, purple and other basic colors, which are determined by the pigments in the pericarp. The flesh of the potato is white, yellow, red or with a purple tinge. The amount of carotene in the flesh affects the intensity of the flesh color. The tuberous roots contain latex, commonly known as white pulp.
Stem
The stem of the sweet potato is usually called the vine or vines. The branches that grow from the main vine are called lateral vines. The length of the vine is generally categorized into two types, namely, the dean type and the semi-upright type. The length of the vine varies greatly depending on the variety, the shortest is only 0.7 meters, the longest can reach more than 7 meters. Soil fertility, planting period and density of stem length also has a great impact. Short varieties of branches, first clumped and then semi-erect or creeping growth; long varieties of branches less, more creeping growth during the growth period, and more rooting in the soil stem nodes. Stem thickness is generally o.4-0.8 cm. The color of the stems are pure green, brown-green, purple-green and all purple several kinds, there are also green stems with purple spots. The surface of the stem is velutinous and the stem has nodes. The nodes of the stems have buds and root primordia, which are capable of growing branches and roots. The cortex of the stem has lactiferous tubes that secrete white latex. If there is a lot of latex when you pick the seedling, it indicates that the seedling is more nutritious and stronger, which can be used as one of the indicators to diagnose the quality of the seedling.
Leaves
Sweet potato is a dicotyledonous plant. Live seedlings first show two cotyledons, followed by true leaves on them. The stem bears one leaf per node, which is arranged in a 22/5 leaf inflorescence in a spiral cross on the stem. The leaves have petioles and blades but no stipules.
Leaves are tomentose on both sides, more densely so on young leaves. The leaf blade is 7-15 centimeters long and 5-15 centimeters wide. Both length and width vary greatly depending on cultivation conditions. There are 2 glands at the junction of the leaf blade and petiole. Petiole length 6-23 cm. The leaf blade has many shapes, roughly divided into heart-shaped, kidney-shaped, triangular and palmate, etc. The leaf margin can be further divided into entire and notched of different depths. The leaf shape of sweet potato varies a lot, not only among varieties, but also among the same plant at different fertility stages and different parts of the leaf shape. Leaf blade, top leaf, leaf vein (leaf blade back leaf vein) and petiole base color can be divided into green, green with purple, purple and so on several kinds, for one of the characteristics of varieties, is the basis for identification of varieties.
Flower
Sweetpotato in botany belongs to the angiosperm family, with flowering instincts, however, the natural conditions of the sweetpotato area varies greatly, different varieties of flowering requirements of the external environmental conditions are different, so the sweetpotato in the flowering of the various places there is also a big difference. In the south of 23 degrees north latitude, the southern part of China's summer and autumn sweetpotato areas, as well as the autumn and winter sweetpotato areas, the general varieties can flower naturally; while in the northern part of China under long sunshine conditions, there is little natural flowering. The flowers of sweet potato are solitary, or several to dozens of flowers clustered into cymes in leaf axils and leaf tops. They are light red, but also purplish red. Which are shaped like petunias (funnel-shaped). Generally smaller. Calyx 5-lobed, ca. 1 cm long. Corolla diameter and flower tube 2.5-3.5 cm long, convolute in bud. Sweet potato flowers are bisexual, with 1 stamen, varying in length, 2 longer, both inserted at the base of the corolla. The pollen sac is 2-celled and longitudinally divided. Pollen spherical, the surface has many symmetrically arranged small protuberances. Pistil 1, stigma mostly bifid, ovary superior, 2-loculed, divided into 4 cells by pseudoseptum. Sweetpotato flowers open in the morning on sunny days and close and wither in the afternoon. Sweetpotato is a heterogamous crop, with a very low rate of self-fruitfulness.
3. Geographical distribution
World distribution
Sweetpotato is distributed in South America and the Greater Antilles and Lesser Antilles, and tropical and subtropical areas around the globe (mainly produced south of 40°N latitude).
Distribution in China
Sweet potatoes are mainly distributed in China in Beijing, Shandong, Henan, Tianjin, Hebei, the three eastern provinces, Inner Mongolia, Yunnan, Sichuan, Hubei, Gansu, Anhui, Fujian, Shaanxi, Hunan, Guangdong, Jiangsu, Jiangxi and other places. The main producing areas in the country are: Sixian County in Anhui (the hometown of Chinese yams), Lulong in Hebei, Liancheng in Fujian, Kaifeng and Dengzhou in Henan, Sishui in Shandong, Nanchong in Sichuan and other areas. Kaifeng dual-season sand sweet potato listed earlier in June listing better body type;
4. Cultivation technology
Nursery methods
Sweet potato needs to be transplanted and planted in the 2 months before the nursery, that is, the spring potatoes in the second half of January to start nursery, autumn potatoes in June in the middle and late nursery, the early winter potatoes in August in the early middle of nursery. One-time seedling can be used, or can be propagated in several times.
Every year, seedling selection is carried out to purify and re-strengthen the seedling. To be in the virus disease and scab disease-free area, and varieties of the same field selection, selection of potato shape long, uniform, no furrow, straight, smooth skin, no pest spots and scars of medium-sized seed potatoes for seed, before planting with 1.0% copper sulfate solution or 2% sodium hydroxide solution soaked 5 ~ 10min [3], can also be used to Bt, white fungi, and other biological fungi permitted by the organic production of soaking seed potatoes for 2h, it is best to use the screen mesh trellis pest-free conditions to propagate detoxified seedlings.
The seedbed base fertilizer should be applied sufficiently, generally per 667 square meters of self-composted organic fertilizer 500 to 1000kg, mineral potassium and magnesium fertilizer 50kg. before seeding, use stone sulfur compound or lime to disinfect the seedbed or smothering shed disinfection.
Seedling management
Sweet potato seedling period according to the seedling situation at the right time fertilizer, fertilizer certified organic or organic certification agencies licensed to use bio-organic fertilizers (NPK nutrient content ≥ 6%, organic matter content of ≥ 40%), the total amount of fertilizer during the nursery period for each 667 square meters is generally 250kg. 1 red buds, generally thin fertilizer; when the seedling height of 10 ~ 13cm, can be carried out in the first two days. 13cm, the 2nd fertilizer can be carried out. After each application of fertilizer, it is necessary to wash the seedlings with water,
Preventing the fertilizer from adhering to the seedlings and causing seedling burning phenomenon.
Cultivate soil can be divided into 2 to 3 times, seedling height of about 10cm, you can carry out the first cultivation, every 7d for the second cultivation, *** cultivate soil 3 ~ 5cm. cultivate soil is best to use fertile loose fine soil mixed with charcoal mud ash or rotting compost, evenly sprinkled into the seedbed. Cultivation of soil can be combined with the application of liquid fertilizer, so that the first cultivation of soil and fertilizer, so that the soil and the base of the seedling close combination, in order to facilitate the early development of new roots, more hair.
After the seeding every 15d spraying Bt and other organic production licensed biofungal agent and 300 times tea bran water, sprinkle 1 time grass ash; and put sex hormone traps around the seedbed or outside the nursery shed.
The seedbed management should also grasp the heat preservation, moisture preservation, ventilation and other measures to temperature. Before the emergence of seedlings, the night to cover the grass curtain, to maintain the bed temperature 25 ~ 35 ℃. After the emergence of seedlings temperature control at 20 ~ 25 ℃, to prevent high temperature scorching seedlings, such as the membrane temperature exceeds 30 ℃, to timely ventilation cooling, to prevent burning seedlings. When the cold wave comes to do a good job of insulation.
The seed potato is generally not watered before seedling emergence, in order to facilitate high temperature germination, disease prevention and emergence. If the seedbed is too dry, use a sprayer to spray water on the seedbed. Seedlings should pay attention to the humidity of the seedbed, when the seedbed whitening to water in a timely manner, wet the bed soil and watering diluted fertilizer to promote the growth of potato seedlings; seedbed is too wet, timely uncovering the film ventilation.
5. Nutritional value
Nutrition
Sweet potato tubers contain 60%-80% water, 10%-30% starch, 5% or so of the sugar and a small amount of protein, oil, cellulose, hemicellulose, pectin, ash and so on, if you take 2.5Kg of fresh sweet potatoes folded into 0.5Kg of grain calculations, its nutrients in addition to fat, protein, Carbohydrate content are higher than rice, flour, and sweet potato protein composition is more reasonable, essential amino acid content is high, especially grain and cereal food in the lack of lysine in the sweet potato content is high. In addition sweet potato is rich in vitamins (carotene, vitamin A, B, C, E), and its starch is easily absorbed by the body. [8]
1. Carotene
Vitamin A has been known as the little guardian of the eyes, vitamin A is transformed from carotene. Sweet potato is rich in carotene, can provide rich vitamin A, vitamin A content can be as high as 40mg/100g fresh white groundnut, carotene is absorbed by the human body, can be transformed into vitamin A. Vitamin A can maintain normal visual function.
2. edible fiber
White groundnut contains fiber equivalent to 10 times the rice noodles, its texture is delicate, does not hurt the stomach, can accelerate the digestive tract peristalsis, help defecation, clean up the digestive tract, shorten the retention time of the toxic substances in the food in the intestinal tract, to reduce constipation caused by the human body's own intoxication, reduce the concentration of intestinal carcinogens, prevention of hemorrhoids and colorectal cancer. At the same time cellulose can absorb part of the glucose, so that the blood contains less sugar, help prevent diabetes.
3. Sugar and protein binding substances
White groundnut is rich in mucin, which is a mixture of polysaccharide and protein, the human body has a special protective effect, can maintain the digestive tract, respiratory tract, joint cavity, membrane cavity lubrication and the elasticity of the blood vessels, due to the substance can prevent substances in the arterial wall of arterial sclerosis caused by the deposition of the liver and kidneys, and other organs can prevent the liver and kidneys and other organs Connective tissue atrophy, can slow down the aging of human organs, improve muscle immunity. White groundnut also contains glycoproteins, has a very good anti-mutagenic, lipid-lowering and enhance the role of immunity.
4. Potassium
White groundnut is high in potassium, which can alleviate the drawbacks brought about by excessive intake of salt. Potassium is also an important factor in protecting the heart. As potassium is an alkaline element, white groundnut has a pH value of 10.31, which is physiologically alkaline and has the effect of neutralizing body fluids. Appropriate consumption of white groundnut is conducive to maintaining the acid-base balance of blood, which is beneficial to people's health, development and intellectual development.
5. Anti-cancer substances
White groundnut there is a physiologically active substances called deoxyepiandrosterone, can prevent colon and breast cancer, brain cells and endocrine glands and the vitality of the endocrine glands have a great role to play, so it can slow down the decline of intelligence and increase the body's resistance. Containing more carotene, lysine, plant fiber, dehydroepiandrosterone, can prevent intestinal cancer and breast cancer.
Therapeutic
Sweet potato is rich in starch, vitamins, fiber and other essential nutrients, but also rich in magnesium, phosphorus, calcium and other minerals and linoleic acid. These substances can maintain the elasticity of blood vessels, very effective in the prevention and treatment of habitual constipation in old age. Unfortunately, most people think that eating sweet potato will make people fat and dare not eat. In fact, on the contrary, sweet potato is an ideal diet food, its calories only 1/3 of rice, and because it is rich in fiber and pectin and has a special function to prevent sugar into fat [8].
Sweet potato is not only healthy food, or a good medicine to get rid of diseases. The Compendium of Materia Medica records that sweet potato has the effect of "replenishing deficiency, benefiting vitality, strengthening the spleen and stomach, and strengthening kidney yin". "Sweet potatoes are steamed, cut, sun-dried and harvested, and are used as food, called yam grain, which makes people live longer and less sick." Gleanings from the Compendium of Materia Medica says that sweet potatoes can nourish the middle, harmonize the blood, warm the stomach and fatten the five organs. The Golden Potato Record says that it has six medicinal values: treating dysentery and diarrhea; treating wine accumulation and heat diarrhea; treating dampness-heat and jaundice; treating spermatorrhea and leucorrhea; treating blood deficiency and menstrual disorders; and treating chancre in children. The Lu Chuan Materia Medica says that sweet potatoes can generate fluids and quench thirst, and cure thirst from fever.
Sweet potatoes contain a lot of fiber and pectin that are not easily destroyed by digestive enzymes, which can stimulate the secretion of digestive juices and gastrointestinal peristalsis, thus playing a laxative role. In addition, it is rich in -carotene is an effective antioxidant, helps to remove free radicals in the body. In fact, sweet potato is also an ideal diet food.