Citrus can be harvested in the fall and before spring sprouting, but it is the best pruning period before the February-March orange in the spring. According to the growth and development of citrus, the plastic pruning was divided into three periods: spring pruning, late spring cropping (pre-flowering) and summer pruning. First, pruning is generally normal in spring and can be pruned from the time of fruit picking to the time of germination in the following year. So fruit growers often arrange pruning in the winter, because the winter is slack, with sufficient labor and time. However, from a scientific point of view, it is the best pruning period before the oranges are sprouted in February-March in spring. Therefore, the spring pruning is also the main pruning period of citrus. Its purpose is to minimize the nutritional loss of the citrus body and try to minimize it. The reasons for reducing the effects on growth and development are as follows: 1. From the beginning of autumn, citrus nutrients transferred from the leaves to the branchlets, branchlets, main roots, and roots. The content of nutrients in the leaves of citrus was highest in autumn (September) and lowest in spring, so it was trimmed in autumn and winter. Because a large number of nutrients in the leaves are gradually transferred to branches, stems, and roots, it will inevitably cause more nutrient losses. Before spring sprouting, the centripetal operation of nutrients has basically ended. At this time, the branches and leaves are cut, and the loss of nutrients is at a minimum. 2. From September to winter, flower buds are in the differentiation stage, and pruning has an effect on flower bud differentiation. One of the purposes of pruning is to reduce the amount of flowers in short shoots. Due to changes in the nutritional level after pruning, it is likely that the buds in some of the remaining branches will continue to differentiate into flower buds, which is not to achieve the desired purpose, and the spring flower bud differentiation has been It is a foregone conclusion. At this time, pruning may be based on people's wishes, and the amount of flowers will be regulated through pruning. 3. The root growth period of citrus is relatively late. It often starts after the spring shooter is long. Before spring, it is pruned before germination. After shearing, it will pump new shoots so that the balance between the branches and roots will not be affected greatly. 4. In the winter, there are cold-damaged citrus producing areas. Our Yuyao region belongs to this category. The spring pruning is caused by the temperature rising, the wounds caused by pruning are not easy to be frozen, and the spring season is immediately followed by the growing season of citrus. The wound is very easy. heal. In addition, a large number of pruning in autumn and winter will stimulate the growth of trees, hinder dormancy, and lead to the tree's resistance to cold. Second, the late spring cut (before flower cut) Early spring pruning, pruning reasonable, can not be cut before flowering, such as early spring pruning is not fine, or improper pruning, this time before the flower to seize the time in time to cut. Since it is generally late in the spring, citrus trees have been used for spring shoots, and flower buds have been planted on flower branches. This is not the time for pruning and should not be trimmed too much. 3. Summer pruning Summer pruning refers to pruning in the growing season rather than summer alone. Its role is to regulate the density of branches inside and outside the canopy, not to close the canopy, in order to enhance the light of the internal ridge, improve the quality of the fruit; control the excessive growth of branch shoots, branches. Mainly take measures such as picking up the roots, wiping off buds, removing sprouts, cutting tips, etc., and on the basis of ensuring that the fruit trees have enough nourishing surfaces, carry out inhibitory pruning. In short, citrus pruning varies according to time. Divided into spring (early spring) pruning, late spring cutting (pre-flower shearing), summer pruning three periods, but these three are closely related, spring pruning is the main pruning, is the pre-flower cut and summer shears The foundation, complex shears and summer shears are complementary to the spring shears and are complementary pruning.