Tree management mainly includes: young trunk shaping and adult tree pruning. Spring pruning is generally carried out from mid-March to mid-April (before germination).
1. Young trees are fixed and shaped. Young trees should be grown sooner rather than later, and the traditional method of drying late and Gao Qian is an important reason for the late fruiting. Proper early drying and low drying are beneficial to early forming and early fruiting. Generally, the stem should be fixed 2 ~ 3 years after planting. When the height of the tree is more than 1 ~ 1.2 meters, the stem height should be about 80 cm, and all the secondary branches below the stem position should be pulled out or left short 1 node.
The tree shape of jujube should be based on the principle of "tangible immortality, intangible chaos" and flexibly mastered according to planting density, variety characteristics and site conditions. The commonly used tree types of jujube trees are evacuation layer shape, happy tree shape, single spindle shape, "Y" shape, cylindrical shape and so on. In fact, all kinds of tree types can produce high yield as long as they are used properly.
2. Prune trees with heavy fruits. Trees in the full fruit period should not be mechanically copied and stick to the tree shape. It should be carried out flexibly in line with the principle of "big branches are bright, small branches are prosperous, old branches are not old, and thousands of branches see the light".
Sparse branches. When encountering overlapping branches or merged branches, the branches with poor fruiting ability, such as too strong and too weak, should be thinned out; For a whorl branch with multiple branches, only one robust fruiting branch is left, and the others are thinned out. In addition, all dead branches, pests, weak branches, invalid branches and useless branches should be removed.
Take it back For weak and drooping backbone branches, select robust branches or robust buds, and cut off the aging branches with bent and drooping front ends to restore their vitality; For cross branches, the branch with relatively low fruiting ability should be retracted to avoid mutual interference.
Update the result branch group. Usually 3 ~ 10-year-old fruiting branches have the strongest fruiting ability. Therefore, the old branches over 10 should be updated in time. The old branch group can be replaced by new jujube heads sprouting near or at the base of the branch group, or the old branch group can be cut off again, and the secondary branches under the cut are thinned, and the old branch group can be replaced by new jujube heads sprouting.
3. Prune old trees. It is mainly to retract the old branches, cultivate new branches and prolong the fruiting period.
Second, management under the tree.
1. Fertilization. Fertilization in spring includes adding base fertilizer in early spring and topdressing quick-acting fertilizer in late spring. At the end of spring, the top dressing of available fertilizer is mainly nitrogen fertilizer, which is carried out before and after germination in April-May. Generally, adult trees should dig 4 ~ 8 small pits with a depth of 30 ~ 40 cm inside the periphery of the tree, and topdressing each tree with 0.5 ~ 1 kg urea and 2 kg calcium superphosphate, and reducing the amount of young trees as appropriate.
2. Plow the tree tray in spring. Spring ploughing should be carried out after the soil is thawed, and the ploughing depth should be 30 ~ 40 cm, and the depth near the trunk should be shallow to prevent the big roots from breaking. Spring is not suitable for plowing in windy areas and periods. Spring ploughing in mountainous areas should be carried out together with repairing and sorting tree trays.
3. Irrigation in spring. There is much drought and little rain in spring in the north, and the irrigation effect is very good in the bud stage. Generally, hole irrigation or furrow irrigation is used. Irrigation amount depends on weather, soil moisture, tree potential and tree age. Spring irrigation is best combined with topdressing.
Third, pest control.
Spring is the key period of pest control. The main pests in spring in jujube area of our province are jujube inchworm, bud weevil, jujube gall midge, green blind stinkbug, etc., which should be controlled as soon as possible in the critical period. For jujube witches' broom, jujube rust, anthracnose, ring rot and other diseases, it is also necessary to clean the jujube orchard in spring, cut off the branches of pests and diseases, and burn them centrally to reduce the occurrence of these diseases. In addition, there are two ways to control jujube witches' broom: one is to drip "Qukuang 1" developed by Hebei Agricultural University into the trunk from late April to early May, which can effectively control the disease and restore the results; Secondly, the new variety "Xingguang" (formerly known as Kangkuang 1) newly bred by Hebei Agricultural University with high resistance to jujube witches' broom can play a dual role in variety renewal and disease tree treatment.