Pruning techniques of walnut trees can be pruned all the year round

walnut trees

Walnut trees can be pruned all year round. Walnut trees are pruned at different times than other tree species. If the period is not appropriate, there will be "bleeding" phenomenon, so that the tree nutrient loss, resulting in tree weakness, under normal circumstances, sub-dormant period and no bleeding period pruning. Spring, summer, autumn, winter four pruning period, different pruning period pruning, appear different problems, pruning effect is also different.

1. Spring pruning. Spring pruning refers to the pruning of walnut trees after germination and before leaf expansion. As the temperature continues to rise, after the tree germinates, the stored nutrients in the roots continue to transport upward, and nutrients begin to transform. This is also the time when the tree needs more nutrients, so pruning at this time will cause bleeding, and will lose a large part of nutrients to weaken the tree vigor, reduce the fruit setting rate, reduce the yield, reduce the quality, and thus reduce the income. If it is a fruit tree or a tree that grows too much, pruning at this time can control growth well, weaken the tree vigor and bear fruit early. Therefore, walnut trees enter the initial fruit stage (early fruit varieties), should not be pruned, should be cut to grow too prosperous and do not bear fruit trees, suitable for late fruit varieties before the initial fruit stage, should promote its early fruit.

2. Summer pruning. Summer pruning must master the pruning period, such as pruning temperature reaches 30℃, walnut fruit exposure, easy to cause burns, nutritional quality decline, thus reducing benefits. It is observed that the best time to finish is from late May to late June. At this time, pruning is combined with scion collection, mainly short, the length of branches is up to 3 cm, and outer buds or lateral buds are kept, and layer spacing is reserved; over-dense branches are thinned, and drooping branches are retracted. Fertilizer and water management must be strengthened after shearing. Specific practice: spray 300 times solution of potassium dihydrogen phosphate from the end of June, once every 10 days, until the end before defoliation. After July, stop applying nitrogen fertilizer and increase phosphorus and potassium fertilizer; do not water from August to defoliation; spray paclobutrazol in mid-September to control growth and enhance pruning effect.

3. Autumn pruning. After walnut harvest to before yellowing leaves (mid-September to early November). At this time, the leaves have not fallen, there is no bleeding phenomenon, too dense branches, shading branches are easy to see, it will be thinned to facilitate ventilation and light transmission. However, the nutrients did not return completely at this time, and the cut leaves and branches carried a lot of nutrients that did not return. And autumn cut wound to winter if the temperature instability will still appear bleeding, and diameter less than 1.5 cm branches shoot slightly heavier (about 2 cm). Therefore, autumn pruning is suitable for pruning weak trees, old trees and walnut trees on hillsides. At this time, no injury flow is conducive to moving large branches and promoting tree strength.

4. Winter pruning. Theoretically, the best period is from the Great Cold to the beginning of spring. Walnut tree bleeding generally begins after defoliation and stops after bud germination in the following spring. However, the whole dormancy period is not always injurious. When the temperature fluctuates around 0℃, bleeding sometimes does not occur. When the temperature is stable above or below 0℃ for a long time, bleeding appears to be trace or does not occur. In addition, the size of bleeding had a great relationship with tree vigor, environment and moisture content, and the bleeding volume of tree decreased with the increase of branch rank. It can be seen that it is feasible to seize the favorable opportunity for winter pruning according to the actual situation of temperature and climate every year, but it should seize the critical period to prune middle and twigs. Pruning at this time can alleviate the conflict between spring, autumn and busy farming time.

In short, walnut tree pruning should follow the following points: increase summer pruning efforts, do a good job of post-shear management. Autumn and winter shear phase combination, autumn shear big branches, winter shear twigs. Growers can choose the pruning period suitable for their own area according to their actual situation.