Grafting and pruning of Walnut trees

Pruning method of trees in full fruit pruning of walnut trees refers to pruning in a broad sense, that is, both pruning and pruning. Trees of different ages have different pruning tasks. The pruning of young trees is to continue to cultivate and maintain the shape of high-yielding trees on the basis of shaping, while the pruning of primary fruit trees is to continue to cultivate backbone branches at all levels, make full use of the early fruit of auxiliary branches, adjust the principal-subordinate relationship of principal and lateral branches at all levels, balance tree potential, actively cultivate fruiting branches and increase fruiting parts. The pruning in the full fruit stage is to regulate the relationship between vegetative growth and reproductive growth, improve the ventilation and light transmission conditions of the tree, maintain the robust growth of the fruiting branch group, and prolong the full fruit period. (1) pruning of backbone branches and peripheral branches. As a result of the extension of the backbone branch for many years, the part of the backbone branch moves outward, the apex is drooping, and the long branch is easy to appear in the back. In the early stage of full fruit, the main branches continue to expand and should continue to cultivate a solid skeleton. Control the back branch of the elongated head in time to maintain the growth of the branch. When the main branch does not need to extend, the head can be changed repeatedly to control the outward expansion. For trees with exuberant growth, the extended branches are often warped, and the main branches are upright, so the back branches should be used to change the opening angle. When the crown reaches the maximum, the tree height can be controlled, the trigeminal branch is used to drop its head to the top year by year, and the uppermost main branch is used to replace the original head. The aim is to reduce the tree height and improve ventilation and light transmission. The branches on the outside of the canopy should be retracted and thinned in time because the outer branches will cause insufficient light in the inner chamber. (2) cultivation and pruning of fruiting branches. On the basis of the cultivation in the early fruit stage, we should continue to cultivate the fruiting branch group, and do a good job of renewal and rejuvenation. Results the branch group configuration should be a combination of large, medium and small, uniformly distributed on all levels of main and lateral branches, and the overall distribution in the crown was small inside and outside, more at the bottom and less at the top, the outside was not dense, the interior was not empty, the permeability was good, and the branch spacing remained 0. 6-1. 0 meters. Results the culture method of the branch group: the large and medium-sized auxiliary branches planted on the backbone branches of ① were retracted into the large and medium-sized branches group; ② used the strong developmental branches to remove the strong and then shrank to remove the strong and the weak, straight and flat, and cultivated into the small and medium-sized fruiting branches group; ③ used the ungrown branches of the inner chamber combined with summer coring to transform the fruiting branch group. In the pruning of the fruiting branch group, the over-strong branch group should be thinned; the weak branch group that has borne fruit for many years should be retracted and renewed in time to promote new shoots; if the branch group is too short, it should be lengthened because it cannot occupy the proper space, so it should be lengthened to promote prosperity and extend forward; appropriate retraction of branches on both sides can promote the growth of extended branches. For the over-prosperous and over-dense branch group, it can be shrinking and sparse, improve the permeability, and make the strong branch group bend and extend, which can restrain the growth of the branch group; the weak short fruit branch and male flower branch in the branch group should be removed in time, so as to promote the robust growth of the fruiting branch group and prolong the fruiting year. The continuous fruiting force of the medium-long fruiting branch group is strong, so it is not suitable to cut short for this kind of branch. (3) the use of growing branches. After the walnut tree enters the full fruit period, the inner chamber is easy to sprout many long branches. if there is space, it can be retracted into a fruiting branch group in time after producing branches, so as to enrich the inner chamber, supplement the space and increase the fruiting position. In the fruiting branch group, the group with moderate growth and a length of 60-80 cm should be selected, which should be released slowly for one year and retracted at the suitable branch the next year. The height of perennial erect branches such as branches will affect the inner chamber light, so it should be retracted, straight and flat, and grow obliquely. (4) treatment of dorsal branches. All the inferior dorsal branches born on the main lateral branches of the first layer are prone to inverted pull, which can be removed from the base in the early stage. The inferior dorsal branch growing on the main lateral branch in the middle and upper part of the crown can be left or left according to the angle and size of the main lateral branch. The large opening angle should be removed, and the small angle can replace the original head to expand the opening angle of the backbone branch. If the growth is moderate and the flower bud has been formed, it can be retracted properly after fruiting and transformed into the fruiting branch group.