Management methods such as navel orange planting and pruning.

The pollen of navel orange degenerates and there are many flowers, but the fruit setting rate is very low, especially in the producing areas with high temperature and humidity at flowering and young fruit stage. If irrigation conditions are available, the fruit-setting rate is higher in the production areas with dry climate at flowering and young fruit stages.

Because navel orange has the characteristics of many flowers, we should pay attention to reducing the number of flowers, improving the quality of flowers and restoring the tree. Here is a brief introduction to the pruning methods of early fruit trees and adult trees.

Pruning of the first fruit tree:

1. Pruning clustered branches: Young navel orange trees tend to sprout clustered branches when they enter the initial stage of fruiting. In order to inhibit vegetative growth, promote reproductive growth and make it enter the full fruit stage as soon as possible, long branches should be cut off in time.

2. Pruning of auxiliary branches and drooping branches: The auxiliary branches and drooping branches planted on the plastic trunk should be treated separately according to their growth conditions. Auxiliary branches with low growth position can be cut off, and drooping branches should be retracted to improve their growth angle. The drooping branches should be recovered after fruiting, and the branches that may bear fruit should be kept as much as possible.

3. Pruning fruiting branch groups and fruiting branches: For fruiting branch groups, fruiting branches or fruiting branches, 1/3 ~ 2/3 should be cut short, strong branches should be cut short less, and weak branches should be cut short or thinned, which is beneficial to the development of strong spring shoots. Stubby branches can shoot in summer and autumn, blossom and bear fruit in the second year, and then cut short after the fruit.

4. Pruning of weak bearing branches and bearing branches: bearing branches with weak growth and no bearing capacity should be cut off, and strong bearing branches should be cut short. After fruiting, the fruiting branches are usually cut off, so as to produce strong spring shoots in the second year, and continue to produce summer shoots and autumn shoots, thus forming good fruiting mother branches.

5. Adjust the growth angle of main branch and lateral branch: It is observed that the angle of main branch is narrow, about 15 degrees, with more leaves and flowers, and the fruit is easy to crack. The main branch angle is about 30 degrees, which has high yield and is not easy to crack. Therefore, when pruning young trees, the main branch should not grow too vertically, and the angle between the main branch and the lateral branch should be open. For some branches with strong growth ability, they can be pressed into a horizontal shape, and the ultra-long branches can be pulled down to weaken the top advantage, promote the sprouting and branching of side branches, increase the yield of middle and lower branches and bearing mother branches in the bore, and improve the fruit quality.

The principle of thinning shoots and leaving shoots is to remove the strong shoots in the upper part of the crown, leave the medium shoots for the weaker branches, and leave the strong shoots in the middle and lower parts and the inner cavity. When thinning the spring shoots, the branches that are too dense should be pulled out together with the old branches and piles of the previous year. Some fruit branches can be shortened, and the top part of the fruit branch above the fruit branch can be cut off. The number of new shoots in the whole tree is about twice that of the fruiting parent branches, and the spring shoots are erased about 3/4. In order to prevent winter buds from sprouting, autumn buds should be planted around beginning of autumn.

(2) Pruning of adult trees: When navel oranges enter the fruiting stage from the initial fruiting stage, in addition to continuing to expand the crown, they should be urged to continuously increase the fruiting amount. When pruning, appropriate measures should be taken to sparse dense branches, control vigorous long branches and shorten extended branches. When navel orange enters the full fruit stage, it should be promoted and controlled in the middle, and the branches should be updated in time to keep the balance between vegetative growth and reproductive growth and prolong the full fruit stage.

1. Pruning of adult navel orange: the method of combining short, sparse and shrinking is often adopted. According to the requirements of controlling the top to promote the bottom and controlling the outside to promote the inside, the branches are distributed reasonably, the upper and lower parts are not overlapped, the right side is not crowded, the structure is compact and the ventilation is transparent.

2. Pruning navel orange at full fruit stage: the outward growth of crown gradually weakened and the roots began to cross. If the management can't keep up, it will cause malnutrition, easy to appear internal baldness, and the leaf curtain layer will become thinner. As a result, the position will move outward to form a surface result, which will sharply reduce production. Therefore, in pruning, besides strengthening the management of fertilizer and water, we should also adopt the method of "one opening, two thinning and three shrinking", combining thinning, short cutting, shrinking branches and heavy pruning, opening skylights for crown, sparse branches, cross branches, overlapping branches and disease and insect branches, and shrinking and updating the aging backbone branches in a planned way, so that the periphery of the crown is sparse, the cavity is full, ventilated and light-permeable, and the three-dimensional results are continuously high-yield.

The key points of pruning are as follows: ① Before entering the full fruit stage, the crown should be enlarged, the yield should be increased, and the upper part of the crown should be sparse, the outer part should be sparse, the inner cavity should be full, the ventilation should be transparent, the layers should be clear, the crown surface should be concave and convex, and the tree shape should be slightly smaller. Keep the side branches short and tidy, and cut off the thick and prominent side branches at the branchlets. ② Prune all kinds of branches reasonably. Navel orange has strong germination ability, weak branches and large flowers. In order to control the amount of flowers, reduce nutrient loss, and improve the proportion of leafy flowers and fruit setting rate, it is advisable to prune twigs, dense branches, overlapping branches and pest branches in early spring. Densely growing branches should be weakened and strengthened according to the methods of "three leaves and two leaves" and "five leaves and three leaves", and branches over 5 cm and thick spring shoots and early autumn shoots with a branch diameter of about 0.3 cm should be kept as much as possible. The lower branches of navel orange have strong fruiting ability and should be preserved as much as possible. For the drooping branches due to load after fruiting, in order to facilitate management and maintain fruit quality, the following measures can be taken: cutting the drooping branches that are shaded or can no longer bear fruit from the base; For the drooping branches that grow well, you can leave the riding branches and take them back year by year to raise them and keep a certain distance from the ground. The internal branch should be retained. The fruit setting rate of inner branches is high, and it is not easy to be sunburned and cracked. Except for over-dense branches, leafless branches and branch tips, the rest are kept. Long branches should be removed from the base as soon as possible, except for branches that can be used to supplement the vacancy in the crown. The fruiting branches and fruiting mother branches should be determined according to the situation after fruiting: the weaker fruiting mother branches should be cut off from the base, if the vegetative branches are produced at the same time, the vegetative branches should be kept and the fruiting branches should be cut off; If the bearing branch is secondary or tertiary, the top 1/3 ~ 1/2 can be cut off to avoid the formation of too long bare branches; The fruit branches are leafless fruit branches, which are cut off from the base after picking; If the leafy and fruiting branches grow vigorously, they can be cut short appropriately so as to produce 1 ~ 2 robust vegetative branches in the second year. Strong summer shoots and autumn shoots can be cut short. Usually, long branches leave 5 buds and short branches leave 4 buds. Short cutting can promote the growth of secondary branches and increase the proportion of fruiting mother branches (navel orange secondary branches are also good fruiting mother branches). Update and trim big branches. Branches crossing the crown should be retracted and trimmed in a planned way, and the trunk branches and big branches that are too dense should be drained in years. The retraction time should be carried out before germination in spring, and the branch diameter of the cutting mouth should be about 65438±0cm. When pruning, leave 1 ~ 2 buds on the cut, and smooth the rest. Declining branches should be regenerated, and the diameter of cutting branches is 1 ~ 2 cm. In addition, in order to avoid competing with young fruits for nutrients, early summer branches should be erased as soon as possible, and late summer branches should be pitted to promote early autumn branches that can be used as fruiting mother branches. Navel oranges have a lot of flowers. After budding, leafless inflorescence branches can be thinned. For leafy inflorescence branches, the second or third flowers or fruits in the middle should be left, and the top flowers and base flowers should be thinned out. For those young fruits that cannot be thinned in time, two robust fruits should be left in each string, and the rest should be thinned.