First, most pear orchards in China are reconstructed by high grafting and replanting of old pear orchards, and the main branches needed for scaffolding shaping are not drained in time after crown restoration, resulting in too many main branches, lateral branches and fruiting branches in the lower part. Because there are many fruits under the trellis, most of the nutrients produced by the leaves flow to the fruits, which leads to the slow upward extension of the main lateral branches needed by the trellis garden, and delays the main lateral branches that should cover the trellis surface for 5-6 years to 8- 10 years or more.
Secondly, according to the latest theory of trellis cultivation, the fruit quality on the surface of trellis is better than that on the main branch and side branch under the surface of trellis, because the fruit handle is in a drooping position, there is no friction between branches and leaves, the fruit shape is square and square, and the illumination is even, and more nutrients are obtained. Because there are many fruits under the shelf, and they are concentrated in the limited three-dimensional space in the center of the inner room, the basic attributes of flat pear fruit in the shed are lost, resulting in concentrated fruit, poor fruit uniformity, inconvenient bagging operation, incorrect fruit shape and low commercialization.
Thirdly, some newly-built trellis pear orchards are not pruned according to the characteristics of trellis pear orchards, or the cultivators lack understanding of the basic principles of trellis pear orchards, resulting in lower trunks and more main lateral branches at the lower part, which are not thinned in time, making the whole orchard look like a trellis orchard from a distance and a traditional three-dimensional orchard from a close point of view, which is neither fish nor fowl.
Solution: First, the cultivator should study hard, deeply understand the basic principle of trellis pear orchard, and master the main points of plastic pruning. Second, for the old pear orchard to be transformed into a trellis pear orchard by high grafting, measures should be taken to retract or remove the main branches and side branches except the extension branches selected as the main branches one year before high grafting, and the remaining fruiting branches or supporting branches on the main branches and side branches should be shortened or retracted to urge them to send out new branches for the next year's trellis pear orchard transformation. Thirdly, on the basis of strengthening the comprehensive management of fertilizer and water after high grafting, after the tree body is restored, the redundant branches in the inner cavity are thinned in time, so that the extension heads of the main branches and side branches needed for scaffolding shaping extend outward as soon as possible, and the side branches and fruiting branches cover the frame surface as soon as possible. Fourth, new orchards should be comprehensively managed in strict accordance with the requirements of scaffolding gardens. Fifth, strictly control the number of fruits below the shelf surface, concentrate nutrition and let the main and lateral branches extend forward as soon as possible, so as to promote all kinds of branches at all levels to cover the shelf surface as soon as possible and lay a good foundation for high yield and high quality. According to Japanese experience, when the branches do not cover the shelf surface, the number of fruits under the shelf surface should generally be controlled at about 5 on each main branch.