(1) Temperature: Winter jujube is a thermophilic tree species and requires higher temperatures during its growth and development. Jujube cultivation in the north shows late germination and early leaf fall. When the spring temperature reaches 13~15℃ (around mid-April in Cangzhou), winter jujube buds begin to germinate. When it reaches 17~18℃, branches will sprout. Jujube hanging will grow, expand leaves and flower buds will differentiate. Flower buds will appear at 19℃. The average daily temperature It enters the initial flowering period when it reaches 20-21℃, and enters the full-flowering period when it reaches 22-25℃. The suitable temperature for pollen germination is 24-26°C. If it is lower than 20°C or higher than 38°C, the germination rate will be significantly reduced. The suitable temperature for fruit growth and development is 24 to 27°C. If the temperature is low, the fruit will grow slowly, have less dry matter, and have poor quality. The suitable temperature during the fruit ripening period is 18 to 22°C. Therefore, the temperature during the flowering and fruit growth periods is an important limiting factor in winter jujube planting areas. When the temperature drops to 15°C in autumn, the leaves turn yellow and begin to fall, and all the leaves fall off by the first frost. It has a strong ability to withstand extreme temperatures in winter. It can tolerate low temperatures of -30°C during the dormant period and short-term high temperatures of 45°C in summer.

To sum up, the lowest temperature in winter should not be lower than -31℃, the average daily temperature during the flowering period should be stable above 22℃ and not higher than 38℃, and the average daily temperature during the fruit growth and development period should be above 16℃ In areas with more than 100 days, winter jujubes can grow normally.

(2) Humidity: Winter jujube is a tree species with strong drought and waterlogging resistance. It has a wide adaptability to humidity. It is distributed in areas with annual precipitation of 100 to 1200 mm. The annual precipitation is 400 to 700 mm. mm is more suitable. The lowest annual rainfall in Cangzhou is less than 100 mm and the highest is 1,160 mm. They can grow and bear fruit normally, and the jujube garden will not die even if it accumulates water for more than 30 days.

Dongzao has different requirements for humidity during different growth periods. The flowering period requires higher humidity, with a relative humidity of 70% to 80%, which is beneficial for pollination, fertilization and fruit setting. If it is too dry during this period and the relative humidity is lower than 40%, it will affect pollen germination and pollen tube elongation, resulting in poor pollination and fertilization and flower drop. Fruit drop is severe and yield is reduced. The "scorch" phenomenon is caused by dry air and low relative humidity. If there is too much rainfall during the flowering period, especially continuous rain during the flowering period, and the low temperature is not conducive to pollination, the pollen will easily swell and crack, unable to germinate normally, and the fruit setting rate will also be reduced. The later stage of fruit growth requires less rain and more sunny weather, with high daytime temperatures and low nighttime temperatures, and a large temperature difference between day and night, which is conducive to sugar accumulation and fruit coloring. Excessive and frequent rainfall will affect the growth and development of fruits, worsen fruit diseases such as fruit cracking and pulp rot, and affect the quality of winter jujubes.

Soil moisture can affect the water balance in the tree and the growth and development of various organs. The field water capacity of the soil is about 70%, which is beneficial to the growth of winter jujubes. When the moisture content of the 30 cm soil layer is 5%, jujube seedlings will Temporary wilting will occur; permanent wilting will occur when the soil moisture content is 3%. Too much water and poor soil ventilation will affect root growth due to suffocation, and long-term water accumulation will also cause death.

(3) Light Sunlight is the basis for the survival of all living things, providing inexhaustible energy and realizing energy conversion. Only under the action of light, the photosynthesis of plants converts the carbon dioxide absorbed from the air and the water absorbed from the soil (including the water absorbed by the leaves) and minerals into organic matter and releases oxygen in the chloroplasts of the leaves, which becomes bioavailable. energy and oxygen needed for breathing. Winter jujube is a light-loving tree species. The growth of winter jujube branches, leaves, fruits and root systems are inseparable from sunlight. Suitable light can promote the growth and differentiation of plant cells, control cell division and elongation, maintain normal photosynthesis, and is beneficial to the accumulation of dry matter in the tree and the healthy growth of various organs. For example, the differentiation and formation of flower buds, quality, fruit setting rate, fruit growth, coloring, and production of sugar and vitamin C are all directly related to light. Not only that, insufficient light will also affect root growth. Because the nutrients required for root growth mainly rely on photosynthetic products above ground, root growth will affect the growth and development of various parts above ground. Photosynthesis is inseparable from the water and minerals absorbed by the roots.

At present, winter jujube orchards that are common in production are densely planted to achieve early fruiting. However, due to improper management, the jujube orchards are closed, and the crown ventilation and light transmission are poor, resulting in an increase in ineffective leaf area and poor leaf production. Decreased ability results in tree weakness, poor growth of jujube heads, secondary branches, and jujube hangings, low fruit setting rate, low yield, poor fruit quality, dead branches in the inner chamber, migration of fruiting parts, and serious pests and diseases. It is necessary to solve the problems of population structure and excessive tree structure in winter jujube orchards through winter pruning and summer pruning and reasonable shaping, so as to achieve the purpose of strong tree body and high quality and high yield of winter jujube.

(4) Soil: Winter jujube has less stringent soil requirements and is highly adaptable. It is a tree species with strong resistance to barrenness and salt-alkali. In the soil pH range of 5.5 to 8.2, the salt content (Binhai It can grow on soil with no more than 0.3%. Both plain wasteland and hilly wasteland can be planted. Especially in 2004, the Party Central Committee and the State Council clearly stated that the development of fruit trees in the future cannot occupy basic farmland. The excellent characteristics of winter jujube, which are resistant to barrenness and salt-alkali, will have special significance in the future adjustment of the agricultural industry and the increase of farmers' income. . The winter jujubes grown on the coastal saline-alkali land in Cangzhou not only grow well, but also produce high-quality winter jujubes that are well-known at home and abroad. Huanghua winter jujube was introduced to the mountainous areas of Beijing and Baoding, and its growth and fruiting are equally good.

However, winter jujube trees on sandy loam and loam soils with deep soil, irrigation conditions, good drainage, moderate soil pH, and high fertility have relatively low investment, good growth, strong tree vigor, excellent quality, high yield, and economical Long life. It has been observed that the surface layer of the plain area is sandy loam and the bottom layer is clay loam. The quality of winter jujube produced on this soil, which is called "Mengjin soil" by ordinary people, is better than that of other soils.

(5) Breeze and gentle wind are beneficial to the growth of winter jujube. They can promote gas exchange, maintain normal concentrations of carbon dioxide and oxygen in the jujube forest, regulate the temperature and humidity of the air, promote transpiration, and are beneficial to jujube. Tree growth, flowering, pollination and fruiting. Strong winds and dry and hot winds are extremely detrimental to the growth and development of winter jujubes. Jujube trees have strong wind resistance during the dormant period, but are not conducive to pollination and fruit setting during the growth period. Exposure to strong winds during the budding period can change the growth status of young branches, inhibit normal growth, and even break branches. During the flowering period, strong winds, especially dry and hot winds, can cause flowers and buds to wither or fail to pollinate, reducing the fruit setting rate. Strong winds during the later stages of fruit growth and before maturity may cause fruit drop or reduce fruit quality. In order to reduce the negative impact of wind on the growth of winter jujube, the garden site should be chosen to avoid wind outlets. Before establishing the garden, protective forest belts should be planted, and technical measures such as water spraying during flowering should be carried out to improve the field microclimate and create a more suitable ecological environment for winter jujube.