Buckwheat
Buckwheat is Polygonum buckwheat crops, scientific name Fagopyrum Mill, annual herbaceous dicotyledonous plants, Polygonum cultivated plants, buckwheat genus. Yi called "forehead", also written in ancient times as oat or oat. Sichuan Province is customarily called buckwheat. Also called "Hu buckwheat".
Annual herbs, short fertility, strong resistance, extremely cold and barren, can be sown many times that year, many harvests. Stem erect, the lower part of the non-tiller, multi-branched, smooth, light green or reddish brown, sometimes with sparse papillae. Leaves heart-shaped as triangular, apically acuminate, base cordate or hastate, entire. Stipule sheaths short cylindrical, tips oblique and truncate, caducous. Inflorescences racemose or paniculate, terminal or axillary. Flowers small, white in spring and summer; pedicel slender. Fruit dry, ovate, yellow-brown, smooth. There are a number of cultivars, especially buckwheat for the most nutritional health value. Stem purple-red, triangular leaves, white flowers, black seeds, ground into flour for food.
Distributed in Europe, Asia and the two continents; China is cultivated throughout the country, sometimes wild, born in the wasteland or the roadside, the seeds are rich in starch, for food, but also for medicinal purposes, is also a honey plant.
History of cultivation
Buckwheat originated in China. Cultivation has a long history. Cultivated buckwheat has four species, sweet buckwheat F. esculentum Moench, buckwheat F. tataricum (L.) Gaertn, wing buckwheat F. emarginatum Mtissner and rice buckwheat Fagopyrum spp. Sweet buckwheat and buckwheat are the two main cultivated species. Has been collected to more than 3,000 local varieties, of which sweet buckwheat, buckwheat each accounted for half.
Buckwheat is one of the important grain crops and relief crops in ancient China. The earliest known buckwheat unearthed in kind in Yangjiawan, Xianyang, Shaanxi Province, four in the Han Tomb, more than 2000 years ago. In addition, Shaanxi Xianyang Maquan and Gansu Wuwei Mazuizi were unearthed in the former Han Dynasty and the latter Han Dynasty, respectively, in kind.
But before the Tang, buckwheat cultivation does not seem to be widespread, "Qimin Yaojiao - Miscellaneous" in the buckwheat, but now generally believe that "Miscellaneous" is not made by Jia Si-feng, but may come from the hands of the Tang. It is said that the "Qimin Yaojutsu - wheat tenth" attached to the "Qu Mai" that is buckwheat, but only a family said. Agricultural books on buckwheat most accurate records are first seen in the "Four Seasons Codification" and Sun Simiao, "Preparing for the emergency Qianjin to be square". At the same time, buckwheat is also mentioned in the relevant poems. Therefore, it is generally believed that buckwheat was popularized in the Tang Dynasty.
The Tang Dynasty with the popularity of buckwheat cultivation, buckwheat cultivation techniques have been summarized. The "Miscellaneous Sayings" is not long, but only for buckwheat records are very detailed. "Miscellaneous Sayings" for the first time described the buckwheat farming cultivation techniques, with special emphasis on harvesting at the right time. "Where buckwheat. May plow. After thirty-five days. Grass rot to turn and plant, plow three times. Before and after the fall are planted within ten days. If the plow three times, that is, three times with seeds. The next two weights of seeds black, the top one weight of seeds white, are white juice, full like thick, that is to be mowed. But it's a good idea to answer to the top of the field. The white ones will gradually turn into black, and this is the right way to go. If you wait until the top of the total black, half already (to) under the black son of all fall." This shows that people at that time for the maturity characteristics of buckwheat and its role in maturation, has been recognized. The Four Seasons - June" has "buckwheat" said: "Autumn in June, that is, ten days before the fall, that is, ten days after the fall in July, that is, ten days after the fall. Setting the fall of the late and the disease, it is appropriate to detail." Song dynasty buckwheat cultivation technology records are not much, but the Song people for the physiological and ecological aspects of buckwheat, but there are a lot of knowledge, the Northern Song Dynasty Chen Shidao in the "Houshan series of talks" mentioned buckwheat and climate and climate relations, "Mid-Autumn dark, the world as one. Buckwheat moon and show. Mid-autumn without the moon, the buckwheat is not solid. Zhu Bent in the "Qiuwei old news" for the form and ecology of a detailed description, which said: "Buckwheat, yellow leaves, white flowers, stems, red, black, yellow roots, but also with the color of the five sides. However, the most fearful of frost when the party fruiting. At this time the rain, it is especially good in the fruiting, and not frost, farmers called 'defrosting rain'. Yuan Dynasty for buckwheat cultivation techniques and a new understanding. First, in the amount of seeding and sowing methods put forward "should be dense seeding, is fruitful, thin is less fruitful". The second is for buckwheat easy to fall characteristics of the harvest method has been improved, the use of a push sickle harvest, Wang Zhen, "Nongshu" said: "Fear of its grains burnt down, it is used to push the sickle to get it." "Farming Atlas" also detailed the structure and function of the sickle can be seen to push the sickle is the earliest type of harvester, and buckwheat is the earliest use of mechanical harvesting of crops.
The cultivation of buckwheat is relatively simple. Because it has a very short full-life span. Can be harvested in the main crop, replanting a mature buckwheat, both to increase the replanting index, but also to facilitate crop rotation with other crops. This situation is more common in the Ming and Qing dynasties. The "Tiangongkaiwu" said "where buckwheat in the south must be mowed rice, the north must be mowed beans and grain and planted. Nongpu Bianli" also said that after the harvest of grain "will be planted to raise wheat". Ma Shou Nongyin" also said "buckwheat in this year's wheat field planted. The Ming Dynasty "to raise more orders", the Qing Dynasty "to save the simple book" and so on pointed out that buckwheat can be mixed with alfalfa, to "buckwheat, alfalfa roots, next year since the birth." Nongsangjing" advocates "more fields, year after year, and vegetable clip planting".
Buckwheat as a traditional crop is widely grown around the world, but the proportion of food crops is very small. World buckwheat refers to buckwheat, buckwheat in foreign countries as a wild plant, but also for fodder, only China has cultivation and food habits. Global buckwheat planting area of 7-8 million hectares, with a total output of 5-6 million tons, the main producers of the former Soviet Union, China, Poland, France, Canada, Japan, South Korea and so on. The former Soviet Union for the world's major buckwheat producers, planting area of about 300 to 4 million hectares, accounting for nearly half of the global total sown area, the average yield per hectare of about 615kg, with a total output of about 2 million tons. China's buckwheat planting area and production ranked second in the world, the 1950s, the planting area had reached 2.2 million hectares, with a total output of 900,000 tons, the average yield per hectare of 405kg, but due to the impact of the buckwheat's own biological characteristics and farmers' long-standing cultivation practices, China's buckwheat in the past as a major disaster relief replanting, treatment of alpine crops, sloppy cultivation, low yields, disconnected from production and marketing, the commodity rate is very low. Commodity rate is very low, coupled with the development of agricultural production and the promotion of high-yield crops, thus reducing the sown area year by year. In recent years, agriculture, medicine and food nutrition research has shown that buckwheat, especially buckwheat, its nutritional value of all food crops, not only rich in nutrients, high nutritional value, but also contains other food crops that lack and do not have special trace elements and medicinal ingredients, modern "civilization diseases" and almost all Old and middle-aged cardiovascular and cerebrovascular diseases have preventive and therapeutic functions, and therefore by the attention of countries. Buckwheat production and health food development has shown new momentum, buckwheat in world trade is also improving its status. According to incomplete statistics in 1986, the country's 20 provinces and districts buckwheat planting area of 722,000 hectares, with a total output of 510,000 tons, an average of 705 kilograms per hectare. About 176,000 hectares of buckwheat, with a total output of 220,000 tons, the average yield per hectare of 1,249.5 kilograms; 546,000 hectares of buckwheat, with a total output of 290,000 tons, the average yield per hectare of 531 kilograms.
Liangshan Prefecture, Sichuan Province, one of the concentrated buckwheat production areas, as Liangshan Prefecture, high above the second half of the mountains of the main food crops, perennial planting area of 60,000 hectares, of which 48,000 hectares of buckwheat, with a total output of 110,000 tons, production accounted for about 1/2 of the national production. 70,000 hectares of arable land suitable for buckwheat cultivation in the whole state. With the development of buckwheat products have great potential as a raw material base, each year to provide thousands of kilograms of commercial buckwheat processing enterprises.
Production significance
1. Agricultural status
Buckwheat short reproductive period, from seed to harvest is generally only seventy to ninety days, early varieties can be harvested more than fifty days. Buckwheat adaptability, resilience, fast growth and development, in the crop layout has a special status: ① in the short frost-free period, precipitation is less concentrated, water and heat resources can not meet the large grain crops planted in the vast majority of dry farming areas and alpine mountain areas are buckwheat production area; ② in the frost-free period is longer, less per capita land and farming is more extensive agricultural areas, buckwheat as a replanting to fill in the leisure crop; ③ in the drought, floods and other natural disasters The impact of drought, flooding and other natural disasters, seedling mortality or loss of the main crop, buckwheat is an important disaster relief crop; ④ buckwheat buckwheat pressure is one of the measures to improve light sandy soils, pressure can increase the organic matter and nutrients in the soil; ⑤ buckwheat can be not easily dissolved phosphorus in the soil into a soluble phosphorus, insoluble potassium can be converted into a soluble potassium, retained in the soil, for later use for absorption.
Buckwheat sowing 3 to 5 days on the seedling, and rapid growth and development, sealing can inhibit the growth of most weeds. Buckwheat planting time-saving labor, in the farm schedule, buckwheat from plowing, sowing to management, usually after other crops, can be adjusted to adjust the farm schedule, the overall arrangement of agricultural production, the realization of the economic benefits of low-input high-yield. With the development of China's buckwheat research and industrial development, buckwheat in agricultural production by the status of the "disaster relief seed" crop into a small crop of economic farmers out of poverty.
2. Nutritional value
Buckwheat is rich in nutrients, according to analysis: its seeds contain protein 7.94-17.15%, fat 2.00-3.64%, starch 67.45-79.15%, cellulose 1.04-1.33%. Japanese scholars reported: buckwheat nutritional efficiency indicators for 80 to 92 (wheat is 70, rice is 50).
According to the Chinese Academy of Medical Sciences Health Research Institute of China's major grain nutrient analysis, buckwheat flour protein content is significantly higher than rice, millet, wheat, sorghum, corn flour and tsampa. Buckwheat flour contains 18 amino acids, amino acid fractions and legumes similar to the amino acid fraction of protein. Fat content is also higher than rice, wheat flour and tsampa. Buckwheat fat contains 9 fatty acids, including oleic acid and linoleic acid content, accounting for 75% of the total fatty acids, but also contains 19% palmitic acid, linolenic acid 4.8%. In addition, also contains citric acid, oxalic acid and malic acid and other organic acids. Buckwheat also contains trace amounts of calcium, phosphorus, iron, copper, zinc and trace elements selenium, boron, iodine, nickel, cobalt, etc. and a variety of vitamins: Vb, Vb2, Vc, Ve, VPP, VP, of which VP (rutin), chlorophyll is not contained in other cereal crops. Nutritional composition of buckwheat grain varies depending on the species and cultivation conditions. These substances play an important role in the body's physiological metabolism. With the development of modern science and technology, people's quality of life, food quality and diversity, buckwheat will be favored as a health food.
3. feeding value
Buckwheat grain, hulls, straw and silage can be fed to livestock, but widely used as livestock feed is crushed grain, rice bran and hulls. Buckwheat grain is a valuable feed, rich in fat, protein, iron, phosphorus, calcium and other minerals and a variety of vitamins, its nutritional value of 70% of corn. It has been reported that buckwheat grain fed to poultry can improve egg production, but also to accelerate the growth rate of chicks; feeding cows can improve the quality of milk; feeding pigs can increase the solid fat, improve the quality of meat. Buckwheat is shorter than other feed crops, both in the short frost-free period in the region of direct seeding, but also in the long frost-free period in the region of replanting, can provide a large number of high-quality green fodder in a short period of time.
4. Honey crops
Buckwheat is one of China's three major honey crops, buckwheat flowers, blossoms, long flowering period, the nectar glands are developed, with flavor, large amount of nectar. Large-scale planting of buckwheat can promote the development of beekeeping and a variety of business, but also to improve the fertilization and fruiting rate of buckwheat. Buckwheat field bee, yield can be increased by 20 to 30% or more.
5. Edible value
Buckwheat flavor, in China's Northeast, North China, Northwest, Southwest, as well as Japan, North Korea, the former Soviet Union are very popular food. Buckwheat food is the direct use of buckwheat rice and buckwheat flour processing. Buckwheat rice is commonly used to make buckwheat rice, buckwheat porridge and buckwheat flakes. Buckwheat flour, like other flours, can be made into noodles, pancakes, bread, pastries, buckwheat cakes, cold noodles, blood and enema and other folk flavors. Japanese people love to eat buckwheat noodles, there are about five thousand soba restaurants. Buckwheat can also be brewed, the color of the wine is clear, drink for a long time to help strengthen the body. Buckwheat leaves are also very rich in nutrients, the development of buckwheat leaves at home and abroad and research is emerging, there is the use of dried leaves to make buckwheat tea, there is also the use of buckwheat seedlings as vegetables.
6. Export
Buckwheat is China's traditional export commodities, China's buckwheat in the international market to "large grain, thin skin, quality" reputation, mainly exported to Japan and European countries. In recent years, due to the progress of scientific research, the medicinal value of buckwheat to get a new understanding of the provinces and districts have been gradually exported by the original grain into deep processing products. Buckwheat in the international market would have been higher prices, China's buckwheat exports each year is still less than one-tenth of the international market demand, so buckwheat exports in foreign trade is in short supply.
7. The use of by-products
Buckwheat is rich in nutrients, not only to the people food, to animal grass, to the poultry material, to the source of honey, but also to prevent and cure disease and health, buckwheat hulls are traditionally a good material to do the heart of the pillow, long-term use of buckwheat hulls pillow has a clearing effect on the eyes. Recent studies have shown that: buckwheat hulls in the ash content of potassium carbonate accounted for about 4.6%, buckwheat hulls of rutin content of up to 30%, buckwheat hulls are now higher than the export price of buckwheat, is estimated to be used in medicine and industrial development and research, so buckwheat deep processing of the utilization of the project is promising. China's buckwheat in recent years, especially buckwheat in the food, brewing, medicine and other areas of industrial development has been in the world's leading position, the export of products than the original grain exports value-added several times to dozens of times.
Buckwheat due to its unique nutritional value is considered to be the world's emerging crops. It is a small crop, but can make up for the lack of advantages of bulk crops and does not have the ingredients: it can be planted in bulk crops can not be planted in a short period of fertility, cold regions and barren soils, it not only contains bulk crops contain nutrients, but also contains bulk crops do not contain and is a necessary component of the human body. Buckwheat is a treasure, young shoots and leaves, stems and leaves, flowers and fruits, roots and stalks, hulls and rice flour without a waste. From the use of natural resources to feed the land to increase production, from agriculture to farming, from the food industry to light chemical production, from food (food and medicine) to health care and disease prevention, from the domestic market to the international market, especially in the Aba State is increasingly emerging in the tourism industry, there are not to be underestimated market prospects, in the characteristics of agriculture, buckwheat will be more to show the unique economic value. Therefore, the development of buckwheat production, buckwheat resource advantages for the commodity advantage, to achieve increased production and income, for improving people's living standards, defense against disease, and promote rural economic development and poverty alleviation in the high mountains, are of great practical significance.
Nutritional value
(a) nutritional quality
Buckwheat is rich in nutrients, whether it is sweet buckwheat or buckwheat, is the seeds or stems, leaves, flowers, their nutritional value are very high. Comparison of buckwheat and other major grain nutrients (Table 1).
From Table 1, buckwheat flour protein, fat are higher than wheat flour and rice. Protein is also higher than corn flour, while fat is lower than corn flour. Vitamin B2 is higher than wheat flour, rice and cornmeal 4 to 24 times, rutin and chlorophyll but for cereal grains are lacking. Mineral nutrients are also higher than other grains to varying degrees. Buckwheat containing protein 9.3% to 14.9%, fat 1.7% to 2.8%, starch 63.6% to 73.1, due to varieties, planting areas and the degree of freshness of the seeds have a greater difference. Compared with sweet buckwheat, buckwheat protein 61.5% higher, 56.9% higher fat, vitamin B2 3.16 times higher, 13.5 times higher vitamin P.
(B) nutritional distribution
Buckwheat fruit hulls obtained after the hulls containing the seed coat or seeds without hulls, called buckwheat rice, sweet buckwheat seeds called sweet buckwheat rice, buckwheat seeds called buckwheat rice. Buckwheat fruit or buckwheat rice can be ground into buckwheat flour to make food. Buckwheat rice nutrient distribution and wheat, rice and other staple grains from the periphery to the center of the same gradual decline in the law, that is, the outer layer of the highest nutrient content, gradually decreasing inward, to the center of the lowest part. Buckwheat rice according to the whole flour, outer layer of flour and heart flour are processed separately, it shows a gradual decrease in nutrient content from the periphery to the center of the law (Table 2).
From Table 2, it can be seen that the outer layer of flour is close to the seed coat part of the flour, high nutrient content, especially other cereal grains do not contain vitamin P (rutin) and chlorophyll.
(C) nutrient composition
1, protein
Buckwheat protein fraction is different from other cereal crops, its high content of serum protein and globulin, accounting for about 46.93% of the total amount of protein, alcohol-soluble proteins and glutenin content is low, respectively, 3.29% and 15.57%, only 1/10 and 1/2 of wheat, while the residual protein is 34.32%, 12.7 times that of wheat flour 2.7% (Table 3). Buckwheat flour and wheat flour this difference in protein fractions, resulting in differences in the processing characteristics of pasta. Buckwheat flour has a very low gluten content, approximating soy protein, low total protein due to rice, wheat and corn.
(1) amino acids: buckwheat contains 19 amino acids, not only high content, and good components. Buckwheat amino acid content per 100 grams of 5.1161 grams, than the wheat content (3.401 grams) 50.42% higher; than the rice content (4.3424 grams) 17.82% higher; than the content of corn (4.653 grams) 9.95% higher; than the buckwheat content (3.1721 grams) 61.28% higher. Amino acids in adults and children essential histidine and arginine are higher, arginine, for example, buckwheat content per 100 grams of 1.014 grams, 0.429 grams of wheat content of 2.36 times as much as 0.745 grams of rice 1.36 times as much as 0.47 grams of maize content of 2.16 times as much as 0.5484 grams of buckwheat 1.84 times.
In the human body in the essential eight amino acids, buckwheat content are higher than wheat, rice, corn and buckwheat. Especially rich in cereal crops are most likely to lack of lysine, buckwheat content is 2.8 times the wheat, corn 1.9 times, 1.8 times the rice, buckwheat 1.6 times. Tryptophan content, buckwheat is 2.4 times the corn, buckwheat 1.71 times, 1.6 times the wheat, and 15% higher than the content of rice.
(2) protein quality: high-quality protein is rich in amino acids, the appropriate proportion of protein. At present, the international often "chemical score" as food protein nutritional value, the higher the value of chemical score, the more digestible protein, the higher the quality. Egg protein composition is close to the optimal amino acid composition of human needs, chemical score value of 100, with eggs as the amino acid composition of the standard, comparing the nutritional value of buckwheat flour, wheat flour, soybean flour and corn flour (Table 4).
From Table 4, buckwheat flour in the eight essential amino acids closest to the egg, lysine, phenylalanine and tryptophan content is higher, but methionine is slightly lower than cornmeal, but also for the 55% of the egg, much higher than wheat flour and cornmeal 40%. Buckwheat chemical score of 55, than the wheat chemical score of 38, rice chemical score of 49, corn chemical score of 40 for the higher, so the quality of buckwheat protein in the grain has a higher value.
EU Hans (M. HAAS, 1994) that the nutritional value of buckwheat protein is very high, chemical score of 81, higher than those listed in Table 4. Moreover, there is a new amino acid "yeast" in the lysine complex.
2, fat
Buckwheat fat content is high, 2.1% to 2.8%, at room temperature in solids, yellowish-green, odorless, different from the general cereal grains. Buckwheat fat component is good, containing 9 fatty acids, the most highly stable, antioxidant unsaturated fatty acids, oleic acid and linoleic acid, accounting for 87% of the total fatty acids (Table 5).
Also in buckwheat contains stearic acid, myristic acid and unknown acid. Stearic acid is 2.51%, myristic acid is 0.35%. Buckwheat fatty acid content varies according to origin.
3, starch and dietary fiber
Buckwheat grain starch content varies by region and species. Buckwheat starch similar to rice starch, but larger particles, compared with the general cereal starch, buckwheat starch is easy to digest and absorb after consumption.
Buckwheat flour contains dietary fiber 3.4% to 5.2%, of which soluble dietary fiber accounted for about 20% to 30% of the total dietary fiber, about 0.68 ~ 1.56%, higher than cornmeal dietary fiber 8%, sweet buckwheat flour dietary fiber 60.39%, is 1.7 times the dietary fiber and wheat flour dietary fiber and rice dietary fiber 3.5 times the standard daily intake of dietary fiber is 20 to 25 grams. Buckwheat as a staple food of the Yi compatriots in Liangshan Prefecture, Sichuan Province survey showed that: consumption of buckwheat has a reduction in total serum cholesterol and LDL cholesterol content, inferred to be from the role of buckwheat dietary fiber. Of course, buckwheat dietary fiber also has the role of chemosynthetic amino peptides.
According to recent studies, the role of digestive starches in human nutrition similar to dietary fiber. Slovenia Kreft (Professor I. Kreft) and other starch hydrothermal treatment test results that buckwheat can be used as a good supplement to the diet of diabetics, because the hydrothermal treatment of buckwheat starch and wheat bread compared to obtain in favor of the slow release of glucose and a relatively high proportion of digestible starch.
4, vitamins
Buckwheat flour contains a large number of vitamins: vitamin B1, vitamin B2, vitamin PP, vitamin P, which is rich in B vitamins. Vitamin B1 and vitamin PP significantly higher than rice, vitamin B2 is also higher than wheat flour, rice and cornmeal 1 to 4 times, has the role of promoting growth, digestion, prevention of inflammation, buckwheat also contains vitamin B6, buckwheat vitamin B6 is about 0. 02 mg/g.
Buckwheat contains other cereal grains do not have vitamin P (rutin) and vitamin C. Rutin is one of the bioflavonoids, is a polyphenol derivatives, is a rutinoside, which and nicotinic acid (vitamin PP) have to reduce blood lipids and improve the permeability of capillaries and vascular fragility. Vitamin P and vitamin C coexist, buckwheat flour in the vitamin P content of some as high as 6% to 7%, while buckwheat contains only 0.3% or so, and the difference in its content in more than 20 times. Buckwheat in the vitamin C content of 0.8 ~ 1.08 mg / gram. And have to promote cell regeneration, prevention of aging effect of vitamin E, the content of 1.347 mg / g.
5, mineral nutrients and trace elements
Buckwheat flour contains a variety of mineral nutrients, human function and food nutrition has caused concern. It is known that buckwheat is an important source of essential nutrients such as magnesium, potassium, calcium, iron, zinc, copper, selenium and other mineral elements. Magnesium, potassium, iron, high content of buckwheat flour to demonstrate the nutritional health functions.
Buckwheat magnesium for wheat flour 4.4 times, 3.3 times the rice. Magnesium involved in the body's cellular energy conversion, regulating myocardial activity and promote human fibrinolysis, inhibit thrombin generation, reduce serum cholesterol, prevention of atherosclerosis, hypertension, heart disease.
Potassium in buckwheat for wheat flour 2 times, 2.3 times the rice, corn flour 1.5 times. Potassium is to maintain the body's water balance, acid-base balance and osmotic pressure of the important cations.
Buckwheat in iron is very sufficient, the content of other staple grains, 2 to 5 times, can fully ensure that the body's production of hemoglobin on the need for iron to prevent the occurrence of iron deficiency anemia.
Calcium in buckwheat is natural calcium, the content of up to 0.724%, 80 times more than rice, food added buckwheat flour can increase the amount of calcium.
The relationship between zinc and taste disorders is striking.
Buckwheat also contains selenium, antioxidant and immune function, in the body can be combined with metal to form an unstable "metal selenoprotein" complex, which helps to eliminate toxic substances in the body. Buckwheat is the National Germplasm Bank as a valuable selenium-rich resources, selenium is the United Nations Health Organization to determine the human body's essential trace elements, but also the organization is currently the only identified anti-cancer elements. Medical research at home and abroad has confirmed that the lack of selenium in the human body will cause dysfunction of vital organs, the human body has more than 40 kinds of diseases and dietary selenium deficiency. American Cancer Institute medical experts pointed out that the right amount of selenium can prevent almost all cancers. The United States advocates a daily dietary selenium intake of 200μg per person, our country because 71% of the region is in a low selenium or selenium deficiency, China's Nutrition Society recommends a daily dietary selenium intake per person is 50μg. At present, Beijing, Taiyuan and other major cities in the results of the survey more than less than 50μg. foreign sources of selenium in food are mostly inorganic selenium added in the feed transformation in the food chain for the second level of absorption, buckwheat selenium For natural organic selenium, green plants as a carrier, so very precious, the development prospects.
6, other
Buckwheat also contains more 2,4-dihydroxy cis-cinnamic acid, containing substances that inhibit the skin to generate melanin, age spots and freckles to prevent the occurrence of the role of. It also contains protein hindering substances that prevent the proliferation of white blood cells.
Morphological Characteristics
1. Root
The root
is a taproot system with a thicker, vertically downward-growing main root, on which lateral roots and hairy roots grow. At the base of the stem or creeping in the ground on the stem can also produce adventitious roots. Roots generally enter the soil to a depth of 30-50cm.
2. Stems
Most species have erect stems, and some perennial wild species have creeping basal branches. The stems are smooth, glabrous or finely tomentose, rounded, slightly angular, solid when young and tender, and hollow when mature. Stem thickness is generally 0.4-0.6cm, stem height 60-150cm, up to 300cm, with expanded nodes, the number of nodes varies according to species or varieties, ranging from 10 to 30. The color of the stem is green, purple-red or red. Stems can form branches, depending on species, varieties, growth environment, nutritional status and the number of different, usually 2 to 10. Perennial species have fat bulbous or rhizome-like stems.
3. Leaves
Leaves include leaf blades and petioles. The leaf blade is rounded-reniform, with a concave base and palmate reticulate veins; the petiole is slender. True leaves are divided into three parts: blade, petiole and ocrea. Leaves are simple, alternate, triangular, ovate-triangular, hastate, or linear, slightly angularly lobed, entire, with palmate reticulate veins. Leaf blade size varies greatly among different types, annual species are generally 6-10cm long and 3.5-6cm wide, with longer petioles in the lower and middle parts, shorter petioles in the upper parts, and almost no petioles at the top. Stipule sheaths are membranous, sheath-like, wrapped around the stem.
4. Inflorescence
Mixed inflorescences of finite and infinite, terminal and axillary. Clusters of spirogynous cymes, racemose, paniculate, or corymbose, borne on the inflorescence axis or branched inflorescence rachis.
5. Flowers
Mostly bisexual. Unipetalous, corolla-shaped, often 5, only the base conjoined, green, yellow-green, white, rose, red, purple-red, etc.. Stamens do not extend or slightly exposed, often 8, into two rounds: the inner round of 3, the outer round of 5. Pistil 1, three carpels united, ovary superior, 1-loculed, with 3 styles, stigma capitate. Nectaries often 8, developed or reduced. There are androgynous isometric, or long-styled short-stamen and short-styled long-stamen flower type.
6. Fruit
Mostly trigonous, rarely 2- or multi-pronged irregular type. The shape is triangular, oblong-ovoid, etc., with an acuminate apex and a 5-lobed persistent perianth at the base. The presence or absence of longitudinal grooves between the ribs of the fruit, the smooth or rough pericarp, the variation in color, and the presence or absence of wings or thorns are the main features for identifying species and varieties. The achene contains one seed, the embryo is hidden in the endosperm, with opposite cotyledons.
Growing conditions
1. Temperature
Buckwheat is a warm crop, the reproductive period requires more than 10 ℃ temperature 1100 ~ 2100 ℃. Buckwheat seed germination optimal temperature of 15 ~ 30 ℃. 4 to 5 days after sowing will be able to neatly emerge. The optimal temperature for the reproductive stage is 18 to 22 ℃; during flowering and fruiting, cool climate and relatively humid air is conducive to yield. When the temperature is lower than 13 ℃ or higher than 25 ℃, the fertility of the plant is significantly inhibited. Buckwheat is weak, afraid of frost, so one of the key measures to cultivate buckwheat, according to the local temperature situation to master the appropriate sowing period, so that buckwheat fertility in warm climatic conditions, flowering and fruiting in a cool climate, to ensure that the maturity of the pre-frost.
2. Moisture
Buckwheat is a wet crop, a lifetime of about 760 to 840 cubic meters of water, more water than other crops; drought-resistant capacity is weak. Buckwheat water consumption at all stages of fertility is also different. Seed germination consumes about 40 to 50% of the seed weight of water, water shortage will affect germination and seedling emergence; buds after the increase in plant size, water consumption increased dramatically; from the beginning of the fruit to maturity of buckwheat water consumption accounted for the entire reproductive stage of water consumption of 89%. Buckwheat water critical period is 17 to 25 days after the emergence of pollen mother cell tetrad formation, if encountered during flowering drought, high temperatures, the impact of pollination, nectar secretion is also less. When the atmospheric humidity is less than 30 to 40% and hot winds, it will cause the plant to wilt, flowers and ovaries and the formation of fruit will also fall off. Buckwheat in foggy, rainy weather conditions, pollination and fruiting will also be affected.
3. Sunshine
Buckwheat is a short-day crop, sweet buckwheat sensitive response to sunshine, buckwheat on the sunshine requirements are not strict, in the long sunshine and short sunshine conditions are able to give birth to and form fruits. From seedling to flowering in the pre-birth period, it is appropriate to give birth to long sunlight conditions; from flowering to maturity of the late reproductive stage, it is appropriate to give birth to short sunlight conditions. Long sunshine promotes plant nutrient growth, short sunshine promotes development. The same variety of spring sowing late flowering, long reproductive period; summer and fall sowing early flowering, short reproductive period. Different varieties of sunshine length response is different, late-maturing varieties than early-maturing varieties of sensitive response. Buckwheat is also a light-loving crop, the response to light intensity than other cereal crops sensitive. Insufficient light during the seedling period, the plant is thin and weak; if the flowering and fruiting period of insufficient light, it causes flower and fruit shedding, low fruiting rate, yield decline.
4. Nutrients
Buckwheat on the nutrient requirements, generally to absorb more phosphorus, potassium. Application of phosphorus, potassium fertilizer to improve buckwheat yield has a significant effect; too much nitrogen fertilizer, nutrient growth, "top-heavy", easy to cause late collapse. Buckwheat on the soil selection is not too strict, as long as the climate is suitable, any soil, including the growth of other cereal crops are not suitable for barren, acidic or newly reclaimed land can be planted, but well-drained sandy soil is the most suitable. The more acidic and alkaline soil can be planted after improvement.
China is one of the origin of buckwheat center, a long history of cultivation, cultivation experience, but because of buckwheat in the crop layout in the position of the long-term attention, before the 1980s, China's buckwheat research is still a gap, although the late start, but the development of faster, especially in the study of cultivation techniques, the establishment of a relatively complete technical system system, in general, to achieve high yields of buckwheat, should achieve six changes : change the stubble Lai land for a good stubble good land; change the rough tillage for intensive cultivation; change the sowing for the strips of reasonable and dense planting; change the fertilizer for the scientific fertilization; change the farm variety for the best varieties; change only planting regardless of fine management.
Cultivation techniques
1. Selection of seeds
Selected varieties is a small investment, quick results, to improve the yield of the first choice of measures, Aba buckwheat varieties, each with a different adaptability, so we need to tailor to suit the local conditions. The main varieties selected by the purification and restoration of local varieties and breeding of "Sichuan buckwheat 1", "West buckwheat 1" and so on. In the second half of the mountainous area selection of "buckwheat", "fine round buckwheat", "Chuan buckwheat 1", buckwheat 1 "and other strong resistance, good yield performance in the middle of the mature and medium-late maturity varieties, can obtain higher yields. In the high two and a half mountainous areas, choose "West buckwheat 1", "pig shit buckwheat" and other cold-resistant and barren varieties, can obtain a more stable yield. In the lower two and a half mountainous areas, the selection of "Sichuan buckwheat 1", "West buckwheat 1", "buckwheat", "water buckwheat" and so on. Early and medium maturity high-yield varieties.
2. Selection of stubble land
(1) Selection of stubble
Crop rotation is an important part of the farming system. Crop rotation, also known as stubble, refers to the same plot of land in a certain number of years in a certain order to rotate planting different kinds of crops, in order to regulate soil fertility, to prevent pests and weeds, to achieve a high and stable crop yield, "stubble such as dung" explains the significance of crop rotation. Continuous cropping leads to a decline in crop yield and quality, more detrimental to the rational use of land. Buckwheat on the stubble selection is not strict, no matter what stubble can grow, but avoid continuous cropping. In order to obtain high yields of buckwheat, the best choice of stubble in the rotation, the better stubble is beans, potatoes, these are land crops; followed by corn, wheat, vegetable stubble, these are land crops, buckwheat is also the main stubble.
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