(1) Select improved varieties and plant them reasonably close.
There are many varieties of jujube trees, each with its own characteristics. However, from the current market, Daxue jujube, Lizao jujube, Zanhuang jujube, Zhanhua Dongzao, Mango Dongzao, Jinsixin No.2, Jinsixin No.3, Jinsixin No.4, Yuanlingxin 1, Yuanlingxin No.2 and Taiwan Province Zizyphus jujuba have higher cultivation benefits.
Jujube planting density can be divided into two types: forest-grain intercropping and early high yield. If the intercropping of forest and grain is planned, it can be considered to plant with a row spacing of 2m× 5m, with 67 plants per mu. Wide rows and narrow plants are beneficial to interplanting crops. The main purpose of early high-yield model is to grasp early high-yield and get benefits as soon as possible. The planting density can be (1.5 ~ 2.0) m× (3 ~ 4) m, and 83 ~ 146 plants can be planted per mu. From the actual effect, the plant spacing is 2 m× 4 m, and 83 plants are planted per mu.
(2) Fertilization
Jujube is a tree species with long fruit development period, and it needs continuous nutrient supply from flowering to maturity. Whether it is a young tree or a big tree with full fruit, it should be based on good application and sufficient base fertilizer. It is best to apply base fertilizer before the end of 10 in autumn, and finish applying it before the end of 12 at the latest. The fertilization amount per mu is not less than 5000 kg. The main types of base fertilizer are soil miscellaneous fertilizer, stable manure and circle fertilizer, and the fertilizer made of straw retting is also very effective. It is best to water it once after applying base fertilizer in arid areas. On the premise of applying base fertilizer, generally in the middle of June, 0. 1 ~ 0.2kg urea can be applied to each 2-3 year old young tree. Jujube trees are topdressing 2 ~ 3 times a year during the full fruit period (excluding topdressing outside the roots). The first time was carried out in the first half of May, and 0.2 ~ 0.3 kg urea was applied topdressing per plant. The second time, in early and middle June, 0.2 ~ 0.4 kg of diammonium phosphate or NPK compound fertilizer was applied to promote the growth and development of young fruits; The third topdressing was carried out from the end of July to the beginning of August, with 0.2 ~ 0.4 kg of urea or diammonium phosphate per plant. In addition, it is best to spray 0.3% potassium dihydrogen phosphate every 15 days from mid-May to before harvesting to promote fruit setting and fruit development.
(3) Pruning jujube trees
The crown of jujube tree expands slowly. Pruning young trees can increase the number of branches, accelerate the formation of crown and form a high-yield skeleton. The purpose of pruning at fruiting stage is to adjust the nutrient distribution relationship and realize high and stable yield.
① Tree selection: There are many tree types of jujube trees, but according to the current cultivation mode, spindle-shaped trees can better meet the needs of close planting and help to achieve early high yield. The tree has an obvious central trunk, the trunk is 40-50 cm high and the tree is about 3 meters high. There are 5-7 main branches scattered on the central trunk, and the main branches are not layered, and one is left every 20-40 cm, which is arranged in a spiral shape, and the resulting branches directly protrude on the main branches. When planting, the stem is fixed at 80 cm, and 5 ~ 7 main branches are cultivated in turn within 2 ~ 3 years. After several short cuts, the middle stem will fall to a height of 3 meters, and the length will be controlled.
② Pruning: The pruning amount of young trees should be small, except for the Yangwang branch and overlapping branch, the other branches should be kept as much as possible. If the main branch angle is not too high, the opening angle can be increased by supporting, pulling and falling, and the amount of branches and leaves can be increased by cutting buds, pruning again and twisting tips in summer.
(4) Improve the fruit setting rate of jujube trees.
1. Open-shell: Open-shell jujube trees, also called girdling, with the purpose of preventing nutrients made above ground from being transported to roots and improving fruit setting rate. The opening hours are slightly different according to the habits of different varieties. Generally speaking, for varieties with heavy falling flowers and difficulty in fruit setting, the best time to open a flower is in the early stage of full flowering, at which time opening a flower can effectively promote fruit setting. Varieties with heavy fruit drop should open their nails after flowering. The position of nailing can be carried out at 25 cm from the ground, and then the height of nailing will move up year by year. The girdling width is about 0.5 cm. When nailing, the incision should be smooth, so as not to hurt the xylem, and only the tough cortex should be peeled off, leaving the cambium. The wound of girdling must be connected into a closed ring, otherwise the effect is not good.
② Tree potential control: Young jujube trees tend to grow vigorously, especially Daxue jujube, Lizao jujube, Dongzao jujube and Taiwan Province jujube. Generally, the growth of seedlings planted in that year is very large. Prosperous growth is very beneficial to the crown expansion and formation of the whole tree, but it also affects the fruit setting rate, resulting in low yield of young trees in 1 ~ 2 years. So we should control the output. For strong and prosperous trees with low seed setting rate, measures such as long-term release and branch pulling can be taken to improve the seed setting rate. Secondly, technical measures such as controlling fertilizer and water and spraying paclobutrazol can be taken to improve the fruit setting rate.