First, the general situation of jujube cultivation in China
According to historical records, there were more than 300 jujube varieties in China, and there are currently 102. In the long-term cultivation history, the varieties of jujube trees have been greatly optimized, and many varieties with good quality and quantity have been cultivated, such as Hebei approximate jujube, Shaanxi golden jujube, Xinzheng Huizao and so on. Jujube trees are widely distributed in China, except Heilongjiang, Jilin and Qinghai-Tibet Plateau in the northeast.
Second, high-quality and high-yield cultivation techniques of jujube trees
(A) adhere to the use of improved varieties and strong seedlings
Using fine varieties is one of the important ways to improve the yield and quality of jujube. Because there are great differences in early fruiting and high yield of jujube varieties, varieties with early maturity, high yield, high quality and strong adaptability and their high quality and strong seedlings should be strictly selected in daily production.
(B) to strengthen soil management
Good soil quality is the key to cultivate jujube trees. By improving the physical and chemical properties of soil, we can create environmental conditions suitable for the growth of jujube roots and promote the robust growth of roots. In the specific operation, we should grasp the principle of "spring is easy to be shallow, autumn is easy to be deep". In winter, during the dormant period of jujube trees, the inner diameter 1.5m should be cultivated to increase the drought resistance and fertilizer conservation ability. After the soil is thawed, turn over the soil within 2m around the jujube tree to increase the ventilation of the soil. For the poor soil quality, the method of deep excavation can be adopted, and the width of the ditch buried in the soil can be changed to 100cm, and 375kg of organic fertilizer can be pressed per hectare to fully improve the soil quality.
(3) Scientific management of water and fertilizer
Before freezing in late autumn, all jujube trees should be applied with base fertilizer, and then topdressing three times before germination in spring. At the beginning of February-March for the first time, each jujube tree was applied with 1 kg urea, 2 kg ammonium sulfate or 3 kg ammonium carbonate, and 25 kg human urine was added with water. The second time before flowering, that is, from late April to mid-May, 0.5kg urea, 0.5 kg ammonium sulfate 1kg and 2.5kg phosphate fertilizer 10% per plant were applied; For the third time, urea 1kg/ plant, ammonium carbonate or phosphate fertilizer 1.5kg/ plant, calcium superphosphate 2kg/ plant, potassium fertilizer 0.5kg/ plant and plant ash 5kg/ plant were applied during the fruit-setting period from June to July. It can also be sprayed continuously with 0.2% urea and 0.4% potassium dihydrogen phosphate solution for 2 ~ 3 times as topdressing outside the roots. Where there are irrigation conditions, irrigation can be done once every 15d before flowering, fruit setting and fruit expansion, and continuous irrigation is appropriate for 3 ~ 5 times.
(D) improve jujube pruning skills
Pruning is a technical measure in the scientific cultivation and management of jujube trees, which can improve the lighting conditions and make the crown form a high-yield structure. The modeling of jujube trees should be based on their growth and fruiting habits, grasp the principle of "pulling out red stripes, leaving gray stripes and taking black stripes", and focus on pruning dead branches, disease and insect branches, overlapping branches, weak drooping branches and long branches and old branches that affect the tree shape. Pruning time depends on the germination time of jujube trees, and should generally be carried out once a year in late May, early June, late June and mid-July.
(5) Improve the management methods of flowers and fruits.
Jujube trees have many flowers and a long flowering period, but the fruit setting rate is low, and the phenomenon of falling flowers and fruits during growth is serious. Therefore, it is the key to obtain high yield and improve fruit setting rate. To this end, the following measures can be taken at flowering stage:
1. The ring peeled off. When the weather is clear, young trees with 30% ~ 50% flowers have an opening width of 0.5 ~ 0.8 cm and a depth of xylem, which does not hurt xylem. The first opening of armor should be 20 ~ 30cm from the ground, and it will increase year by year. The climate in the northern region is relatively dry, so it should be wrapped with plastic film after nail opening to prevent water evaporation and promote healing.
2. Tips. Removing jujube head is one of the methods to improve fruit setting rate. One month after the peak of rapid growth of jujube head, the effect of stone removal is better. Generally, the jujube heads of strong branches, main branches and regenerated branches are picked again, and the jujube heads of weak branches, horizontal branches and secondary branches are picked lightly.
3. spray auxin. Spraying gibberellin 5 ~ 50mg/kg, 2,4-D 5 ~10mg/kg and NAA15 ~ 20mg/kg in full bloom; Spraying 20 ~ 100 mg/kg NAA, 60 mg/kg 2,4-d or 50 mg/kg gibberellin at the young fruit stage can improve the fruit setting rate of jujube trees.
4. Spray water when flowering. The flowering period of jujube trees is sometimes prone to high temperature and dry climate, which leads to the withering and falling of jujube flowers. At this time, jujube trees should be sprayed with water in the morning and evening to increase the air humidity, so as to improve the fruit setting rate.
In addition to the above methods, releasing bees at flowering stage can also effectively increase the yield of jujube trees.
(6) Pest control measures
The main diseases of jujube trees are jujube madness and jujube rust. Jujube witches' broom is highly contagious, and there are no good control measures for jujube witches' broom at present. Once the diseased plant is found, it should be eradicated and burned in time. Jujube tree rust, jujube farmers can spray 1: 2: 200 bordeaux solution on jujube trees every 20 days in early July; Or spraying 50% carbendazim 800 times can achieve the control effect.
The pests of jujube trees include peach moth, jujube armyworm, jujube inchworm, jujube gall midge, jujube fruit fly and so on. In order to prevent such pests, jujube farmers should dig deep into jujube orchards in winter and spring, collect insect cocoons and eliminate insect pupae. Every February, a layer of plastic film is tied to the base of the trunk to prevent the female moth of jujube geometrid from laying eggs on the tree. Spraying 50% Bataan solution 800 times on jujube trees in April-May every year can control jujube tree armyworm, jujube tree inchworm, jujube tree gall midge and jujube tree fruit fly. June is the incubation period of the scale. At this time, spraying 400 times of 25% phoxim can prevent it. Spraying 1500 times of 90% Bataan wettable powder to control peach fruit borer in early August.
(7) timely harvest
Scientific control of jujube harvesting can not only improve the yield and quality of jujube, but also be beneficial to the growth and development of jujube. According to the change of peel color and pulp texture, the ripening of jujube can be divided into three stages: white ripening, crisp ripening and complete ripening. If the harvested dates are used as candied dates, they can be harvested at the white mature stage before the green color on the fruit surface fades to white green. If the jujube is dried in the sun, it can be harvested at the mature stage of jujube red and slightly wrinkled peel.
There are two kinds of harvesting methods: manual harvesting and chemical harvesting. Manual picking refers to picking after the fruit is fully ripe. Manual harvesting consumes a lot of manpower. At this time, 200 ~ 300 ppm ethephon aqueous solution can be sprayed evenly on jujube trees, and the fruit can fall automatically after 5 ~ 6 days.
References:
[1] Shi, Han, Guo. High-yield cultivation techniques of jujube [J]. Shaanxi Forestry, 2009(6).
, week,. Cultivation techniques for high quality and high yield of jujube [J]. Gansu Forestry Science and Technology, 200 1(3).