The reason why grapes are pruned in summer is because the winter buds of grapes are compound buds, and sometimes two or three new shoots can grow from one bud eye, and the new shoots of grapes grow rapidly, and secondary buds can be issued two or four times a year. If pruning control is not carried out in the growing season, the branches and vines will be too dense, which will affect ventilation and light transmission, disperse and waste nutrition, thus reducing the fruit setting rate and berry yield and quality, resulting in smaller fruit grains, loose fruit ears, lower sugar content, color difference and delayed ripening. Therefore, grapes must be carefully pruned several times a year.

The common pruning methods of grapes in summer are: bud wiping, branch fixing (thinning), inflorescence thinning, spike pinching, secondary spike thinning, tendrils removing, new shoot center removing, secondary shoot processing, dead shoot cutting, new shoot tying, shoot cutting and leaf picking.

(1) bud wiping

After germination in spring, it should be carried out before the new shoots grow to 5 ~ 10 cm, and the redundant and useless buds should be erased as soon as possible, and the buds on branches and vines within 30 ~ 50 cm near the ground. Otherwise, it is easy to mop the floor, infect and spread diseases, and affect ventilation and light transmission. If there are more than two new buds in a bud hole on the shelf surface, one with good growth and inflorescence should be selected, and the rest should be erased. The dense buds on the main vines and branches should also be erased as soon as possible.

(2) Fixed branches (thinning branches)

When the new shoots grow to 1.5 ~ 20 cm, the presence and size of inflorescences can be seen, which is an important work to adjust the density of remaining branches on the basis of bud wiping. According to the growth potential of varieties, there are 15 ~ 20 branches per square meter of scaffolding. When the new tip of single hedge frame is tied vertically, a new tip shall be left every 10 cm, and a new tip shall be left every 15 cm for double hedge frame. When fixing branches, leave a margin of 10% ~ 15% to prevent new shoots from being blown off by the wind and man-made losses.

(3) Sparse inflorescence, pinching ear and sparse secondary ear

In order to concentrate nutrition, improve fruit setting rate and fruit quality, and ensure reasonable yield burden, it is necessary to sparse inflorescences, especially varieties with many inflorescences, large inflorescences and serious fruit drop. Flowering usually takes place 10 ~ 15 days before flowering. The standard of inflorescence maintenance is: fresh food species generally have one inflorescence per fruiting branch, spikelet varieties and a few strong branches can have two inflorescences, and weak branches do not need inflorescences.

Spike pinching and secondary ear thinning can be carried out simultaneously with flower thinning. For varieties with large and long inflorescences, 1/5 ~ 1/4 of the total inflorescence length should be pinched off, and part of the top of the branches that are too long should also be pinched off. For varieties with large panicle and obvious accessory panicle, the oversized accessory panicle should be cut off, and the branch of 1 ~ 2 at the base of panicle axis should be cut off. By pinching the tip and thinning the secondary ear, the poorly differentiated spike tip and secondary ear can be removed, the nutrition is concentrated, the fruit setting rate is improved, the fruit ear is dense, the fruit grain size is neat, and the ear shape is neat and consistent.

(4) removing tendrils

Tendrils not only waste nutrients and water, but also damage leaves and fruit ears, so that new shoots are entangled together, which brings trouble to future operations such as tying shoots, picking fruits, cutting fruits in winter and removing them from shelves. Therefore, the tendrils should be cut off in time when cutting in summer.

(5) Picking new buds.

The purpose of pinching new shoots is to control the vigorous growth of new shoots, concentrate nutrients on the remaining inflorescences and branches, improve fruit setting rate, reduce flower and fruit drop, and promote flower bud differentiation and new shoot maturity. The new shoot coring method is as follows:

① The coring of fruit branches should be carried out from 3 to 5 days before flowering to early flowering, and it is generally more suitable to leave 4 to 6 leaves above the inflorescence for coring.

(2) Nutritive branch coring and fruiting branch coring are carried out at the same time or a little later than fruiting branch coring, and generally 8 ~ 12 leaves are left. Strong branches stay long and weak branches stay short; Keep the space long and the secret short.

(3) The coring time of main spreading long branches can be determined according to the expected length of winter shear and the length of growth period. The northern region has a short growth period and should be picked before mid-August; The growing season in the south is long, and you can pick your heart in the first half of September. Generally speaking, there is no spike left in the extended shoots to ensure their robust growth and complete maturity.

(6) Secondary tip treatment

With the extension of the growth of new shoots and the stimulation of coring, the summer buds at the axils of new shoots will germinate secondary buds. In order to reduce the consumption of invalid nutrients, prevent dense branches and leaves on the shelf surface, and ensure good ventilation and light transmission and berry quality, the secondary branches should be treated properly in time during the growing season. Results One secondary branch at the top of the branch kept 3-4 leaves for repeated coring, and other secondary branches kept 1 leaf for repeated coring. This method is suitable for young trees and vigorous trees. Because young trees are treated in this way, there are many secondary leaves, which can promote the growth of roots and thicken the main vines; After treatment, the strong and prosperous trees can disperse nutrition, balance tree vigor, leave more secondary branches and prevent overgrowth. ? Erase the secondary branch from the base, leave 1 leaf on the spike for repeated coring, and leave 2-4 leaves on the top secondary branch for repeated coring. This method is suitable for early fruit trees. Leaving more secondary top leaves can ensure early high yield, promote crown enlargement and thickening of fruiting branches, which is beneficial to cultivating branches. ? Results Only the auxiliary tip at the top of the branch was kept, and 2 ~ 3 leaves were left for repeated coring each time, and the other auxiliary tips were erased from the base. This method is suitable for mature (whole fruit) vines cultivated in hedgerows and scaffolding. Because there are fewer leaves, the thickness of the leaf curtain layer can be reduced, so that the shelf surface can penetrate dim light, so that the leaves and ears under the shelf can see light, which can reduce the appearance of yellow leaves and promote fruit coloring and ripening. In the forming process, this method is usually also used to expand the long tip.

(7) Cut off dead branches and bad branches

Usually after the bleeding period of grapes. In the north, it is mostly in early June, which can be done together with coring. The reasons for the formation of dead branches and bad branches are: the branches themselves are not full, the maturity is not good, and the bud eyes do not germinate; Grapes are mechanically damaged when placed up and down; In winter, the bud eyes are frozen and do not germinate. Cutting off dead branches and bad branches can reduce the consumption of nutrients and water, improve ventilation and light transmission conditions, and reduce pests and diseases.

(8) New cutting-edge binding

At the same time, in summer, some drooping branches and over-dense branches should be scattered and tied tightly with iron wires to improve lighting and ventilation conditions, improve quality and ensure the smooth progress of various operations (spraying, summer cutting, weeding, etc.). ).

(9) Pruning and picking leaves

It is carried out from the middle and late July to September, especially before fruit coloring. Cut off some new shoots and auxiliary branches that are too long, and remove too dense leaves (especially old leaves and yellow leaves) to improve ventilation and light transmission conditions, reduce nutrient consumption and promote fruit coloring. Shoot cutting and leaf picking should be based on the screen light and shadow under the frame, and should not be too heavy.

Three problems should be paid attention to in summer pruning: first, the cut branches and leaves should be buried or fertilized intensively, and they should not be thrown around to reduce pests and diseases; Second, the diseased leaves, branches and fruits found during pruning in summer should be cut off in time and buried deeply to prevent the spread of diseases; Third, all operations must be carried out strictly on time and as required.