What is the earliest date of birth? Is there any historical record?

Jujube originated in China and has been cultivated for more than 5000 years. Although it is also distributed in Japan, the United States and other countries, it has not been commercialized, but is a fruit tree widely cultivated as an important specialty in China. Jujube is delicious and nutritious. The sugar content of jujube ranks first among all kinds of fruits. Fresh jujube contains more than 20% sugar, and dried jujube contains 60% ~ 80% sugar, which can replace grain and is an important woody grain. Jujube is rich in vitamins and has the reputation of "natural vitamin pills". Its vitamin C content is 10 times higher than that of citrus and 80 times higher than that of apple. The content of vitamin P is also extremely rich. In addition, red dates are rich in protein and inorganic salts such as iron, calcium and phosphorus. In addition, since ancient times, Chinese working people have regarded jujube as an important tonic and Chinese medicine. There is a folk proverb that "eat three jujubes a day, and you will never get old" and "five grains and red dates are better than ganoderma lucidum", which highly praised the nourishing and medicinal effects of jujube. Modern medical research shows that jujube has the functions of moistening heart and lung, lowering blood pressure, nourishing five internal organs and treating deficiency. Long-term use can tonify the middle energizer, strengthen the body and prolong life. Generally, Chinese medicine should be accompanied by a little jujube, so jujube can be called "the guide of all medicines". Foreign studies have also found that jujube also contains substances such as cyclic adenosine monophosphate, which has special effects on inhibiting the division speed of cancer cells. Jujube wood is hard and fine-grained, and can be used to make axles. It is a good material for national defense or civil use. Jujube has a long flowering period and is rich in honey, which is a good honey source and greening tree species. Jujube was originally a subtropical desert plant and a famous "hardcore crop". Therefore, it has strong adaptability and is a pioneer tree species suitable for cultivation in barren wasteland. Can withstand the high temperature of 43℃ in summer and the low temperature of -33℃ in winter. When the soil pH is between 5 and 8.6, jujube can grow and bear fruit normally. It is famous for its drought resistance, barren resistance and saline-alkali resistance. There is a saying in the fruit industry that "pears are waterlogged and dates are dried", but dates are also extremely waterlogged. It is also recorded in the ancient book "Qi Yao Min Shu": "In the land of drought and flood, you can plant dates without plowing crops." For example, in 1965, Jinsixiaozao Garden of Dusheng Brigade in Cangxian County, Hebei Province was flooded to 1 m, and the flooding time was as long as one month. All the apple trees were drowned, but the jujube tree still survived and grew normally the next year. Whether it is barren gravel soil in mountainous areas, low-lying saline-alkali land along the coast, acidic soil in the south or gravel soil in the north, when the yield of other crops is not high, planting dates will have a good harvest. For example, in the border area between Cangzhou, Hebei Province and Dezhou, Shandong Province, the soil pH value is above 8.2, and the alkalinity is heavy, but it is the concentrated production area of jujube, while the barren slope in Taihang Mountain area is rich in jujube and Zizyphus jujuba ... jujube trees can reliably start from the edge, go down the beach, go uphill and enter the ditch, which provides regional guarantee for their large-scale development. In addition, jujube trees can also be planted in canals, ditches, dams, ponds, villages and roadsides. In a word, this strong adaptability of jujube tree is incomparable to any other fruit tree. There is a saying in the fruit industry that "jujube pays back the money that year", which means that jujube can bear fruit that year to recover the cost. Three-year-old jujube orchards are densely planted, and the yield per mu can reach about 1400 kg. After entering the high-yield period, the yield per mu can be maintained at 2500-3000 kg, the output value per mu can exceed 10,000 yuan, and the normal fruiting period can reach 100 year. The yield per plant has been reported in China, and jujube trees over 500 years old still have a certain yield. For example, a 300-year-old jujube tree in Shandong can still bear 65438+ every year. It is particularly important that there is no sales pressure on the date. If fresh dates can't be sold, they can also be made into dried dates and candied dates for sale, which greatly prolongs the sales period and relieves the worries of fruit farmers. Although jujube is a unique fruit tree in China, it has been neglected for a long time. Due to extensive management, the yield is very low, and it developed very slowly before 1995. According to the latest statistics, at present, the cultivation area of jujube trees in China is about 4.5 million mu, with a total output of 600 million kg. According to the forecast of relevant departments, the annual demand of Chinese jujube is more than 654.38+0.5 billion kilograms, with a big gap. In addition, the geographical distribution is extremely unreasonable, mainly concentrated in Shanxi, Hebei, Shaanxi and Henan in the north, which account for more than 95% of the country's total area and total output. In the vast southern region, except for a few towns and villages in Guangxi, Jiangsu, Hunan and other provinces, it is extremely difficult to see a jujube garden. Therefore, in southern provinces, jujube is the weak link and unpopular in the development of fruit trees at present. All localities should make full use of this opportunity of industrial restructuring and put the development of jujube trees on the important agenda. Regarding the planting density of jujube, in the past, in order not to affect grain production, it was mainly jujube-grain intercropping. The planting density per mu is very thin, generally only a few dozen plants per mu, and the yield is very low. Facts have proved that sparse planting is the main reason for the low yield per mu. Therefore, in order to greatly increase the yield, it is necessary to carry out close planting. The yield of dense planting garden can be increased by 3 ~ 5 times than that of sparse planting garden. The density of closely planted jujube orchards varies with varieties, management level and other factors. For example, our demonstration garden adopts ultra-high density, with per mu 1 1,000 plants (1m×0.67m). As a general production unit and individual, our company recommends to produce 333 plants (2m× 1m), 222 plants (2m× 1.5m) and 167 plants (2.5m× 1.6m) per mu. Jujube seedlings can be planted from June 10 to April 10. We have cultivated 500,000 jujube seedlings this year, the height of which is more than 40 cm. The varieties are briefly introduced as follows: 1. Similar to jujube, it is native to Hebei. It is named because it can pull out long yellow gold wire after it is completely mature and dry. Compared with similar jujube, the latter is natural triploid and the only triploid jujube variety in China. The longitudinal diameter was 7. 1 cm, the transverse diameter was 3. 1 cm, the average fruit weight was 17.3 g, the maximum fruit weight was 29 g, and the size was neat. The fruit surface is flat, the fruit point is small, round, inconspicuous, medium density, slightly convex, and the color is similar to that of the peel. Fruit shoulder is oblique, slightly convex, with 4 ~ 5 grooves. The stem depression is small and medium depth. The ring depression is narrow and deep, the top of the fruit is wide and round, and the top is slightly concave. Stigma absent, punctate. The pulp is nearly white, dense and delicate, crystal clear as ice, medium juice, and the soluble solid content is 30.5%. The edible rate is 96%, the drying rate is 47.8%, and it tastes as sweet and delicious as cheese when eaten fresh. Dried red dates are full and elastic. After drying and crushing, 30 ~ 40 cm long honey silk keeps flowing, so it is called "golden honey". The meat is sweet and the quality is extremely high. The stone is spindle-shaped, yellow-brown, with a longitudinal diameter of 2.2 cm, a transverse diameter of 0.8 cm, and a stone weight of 0.7 g. The stone grain is vertical and has a moderate depth. The tree is vigorous, with weak branches, strong uniaxial elongation, sparse branches and strong disease resistance. The grafted seedlings began to bear fruit in the second year, and the yield was high and stable. Ripe and harvest in late September, the fruit growth period is about 1 10 days, and mature and listed in Chongqing in the middle and late August. This variety has big fruit and small stone, high quality, beautiful appearance and high yield, and has great development potential.