First of all, the vigorous growth of the peripheral vegetative spring shoots and more than five leafy fruit branches in the middle and upper part of the crown must be completely removed, and the growth of summer shoots should be controlled from mid-July after fruit setting to reduce physiological fruit drop. For young trees that grow vigorously but don't bloom, a belt-shaped or annular ditch can be opened in the crown drip line from mid-September to late October of 10. 10- 15 before the autumn shoots put fruit, at this time, the big top fruit in the middle and upper part of the crown must be removed. When the number of autumn shoots is large, it is necessary to shorten or retract the weight of autumn shoots of the whole tree 1/3, which can reduce the amount of flowers in the next year.

First, the winter pruning method of Vogan

1. First, more than 5 peripheral vegetative spring shoots and leafy fruiting branches in the middle and upper part of the crown must be thinned out. From fruit-setting period to mid-July, the growth of summer shoots must be strictly controlled to reduce physiological fruit drop. When the summer shoots stop growing and spreading leaves, you can still leave 1-2 leaves for coring or cut off the basic branches, so you must choose to put the autumn shoots in the suitable climate and the low peak period of leaf miner.

2. For young trees with vigorous growth and no flowering, from mid-September to the end of flower bud physiological differentiation period 10, a strip or annular groove can be opened at the crown drip line, and the root cutting thickness must reach 0.5-37. .5px. Trim and cut off the roots, and dry for 30-60 days. Fill the soil when the leaves are slightly rolled, and combine with deep organic fertilizer when filling.

3. Before the autumn shoots are released 10- 15 days or so, the big top fruit on the periphery of the middle and upper part of the crown is removed or cut off with sepals to release the autumn shoots and replace the twigs with fruits.

4. The fruit setting rate of some varieties of Wogan is very low, and the flower and fruit drop are very serious, especially for trees with large flowers. Usually, these fallen flowers and fruit branches are pruned in winter. In order to save nutrients, summer pruning must be adopted, and autumn shoots should be shortened or retracted before putting out branches from late June to early July, so as to cultivate excellent fruiting mother branches.

5. When there are many autumn shoots, the autumn shoots of13 of the whole tree should be cut off or recovered, and the weak shoots should be thinned to reduce the flowers in the next year. If the control of summer shoots is not complete, that is, the branches are not advanced, autumn shoots can be used for treatment.

6 dead branches, pests and diseases, dense branches, weak branches, cross branches, upright branches, drooping grounding branches, etc. , pests and diseases, which greatly hinder the growth of trees, must be cut off immediately during the growth period, and others must be cut off during pruning in winter.

Second, the characteristics of Vogan

1. Vogan fruit is of medium size, and the weight of a single fruit is about130g. The fruit is oblate, with a transverse diameter of 6.7cm, a longitudinal diameter of 5.7cm and a fruit shape index of 0.85. The peel is smooth, orange or orange-red, with fine oil cells, slightly convex or flat fruit surface and few pits. The top of the fruit is flat, with a very inconspicuous printed circle, and the radial grooves in the columnar area are not obvious. The peel is tightly wrapped, 0.36cm thick and easy to peel. The sponge layer is yellow and white with petals 9- 1 1.

2. Orange, red orange, bitter orange and orange can be used as rootstocks in production, but they have graft incompatibility with pomelo, so pomelo must not be used as rootstocks. In areas with high calories, strong rootstocks such as Volka Mo and rough lemon can't be used, so as to avoid the low acidity of fruit and make the flavor fade. The main characteristics of grafting Wogan are fast growth and high yield, and the characteristics of Fructus Aurantii are good taste and strong drought resistance.

3. Wogan grows vigorously, the fruit hangs on the tree for a long time, and the demand for fertilizer and water is relatively large. Basic fertilizer must be applied again in production, which is mainly composed of decomposed and fermented farmyard manure and compound fertilizer. When planting in purple soil and barren sloping land, it is necessary to strengthen soil improvement, apply more organic fertilizers and phosphorus and potassium fertilizers, and supplement zinc and magnesium fertilizers appropriately to ensure the dark green leaves.