Pruning-related growth and fruiting habits of walnut fruit trees

  1. Bud heterogeneity and branch strength bud heterogeneity refers to the difference of bud growth potential and other characteristics caused by different environmental conditions and different nutritional conditions in different parts of the same branch during development. Bud heterogeneity is called bud heterogeneity because of the difference of bud formation stage, nutrition condition, hormone supply and external environment condition. If the bud at the base of the branch occurs in early spring, it is at the beginning of growth, the leaf area is small, the temperature is low, and the bud quality is poor. If the branches can stop growing in time, the terminal bud quality is the best. The quality of axillary buds mainly depends on the size of leaves and the ability to provide nutrients, because the nutrients and energy for bud formation mainly come from leaves on the node, so the quality of buds at the base of branches and thin tips is generally poor. Bud heterogeneity was mainly utilized in bud selection by pruning shears.

  Walnut branches increased, scattered nutrients moderate growth, conducive to the accumulation of nutrients, thus promoting flower bud differentiation, for early fruit, high yield laid the foundation. Branches increased, leaves also increased relatively, the production of organic nutrients is also more, promote the accumulation of nutrients, but too many branches, poor light, this needs to be adjusted through plastic pruning, young trees when the main branches more open angle also becomes larger.

  Walnut inclined branch polar growth weakened, growth potential turned to both sides, so the two lateral branches easy to expand, increase the number of branches and leaves, can be early flowering results, so walnut tree trunk branch requirements angle to open. A small number of main branches, small opening angle, a large number of main branches, large opening angle, are conducive to early fruit, high yield. The main branch is few, angle is small also can obtain more illumination, can bear fruit. The main branches are many and upright, and they are bound to be densely crowded, and the poor light results are reduced; but the opening angle is large, although the main branches are many, the light is also improved, and the fruit can still be produced. This is the role of walnut tree self-regulation.

  2, the top advantage of the technical strip General tree species have a strong top advantage, its advantage is often due to the variety type, age tree vigor, planting methods vary. In general, apical dominance decreased in the order of erect, oblique and pendulous branches, in other words, apical dominance was weaker in branches with larger angles. Using these characteristics, young trees should enlarge crown early in shaping period, develop branches should be less short, and use the top advantage of big terminal bud to promote strong long branches.

  Walnut top advantage is strong, he is full of terminal buds easy to pull out Wangzhi. The proportion of lateral buds, shoots and fruits below the terminal buds is very small, especially the lateral buds in the middle and lower parts of the branches, mostly dry and fall off by themselves, forming bare bands. As a result, walnut tree canopy more sparse.

  Top dominance is the vertical growth of branches, top growth predominates, growth is the strongest, downward successive decline. The top of inclined branches became lower, the dominance weakened, the top grew slowly, the middle and rear grew stronger, showing that the number of sprouting branches increased. The horizontal branch has no towering top, and there is no advantage. The growth potential is equal before and after, and the growth is moderate and the branches are uniform, which is beneficial to flowering and fruiting.

  3, layer due to the role of the top advantage, the top of the long branches of several buds developed into large strips, the upper and middle buds developed into medium and short strips, the lower buds do not germinate into bare strips, every year according to this characteristic growth, so that after growing into a big tree, the main branches were layered distribution on the tree, which is layer. The young trees can be shaped in time by shaping and pruning according to the layering, and the trees have distinct layers and good illumination, high and stable yield and high quality. For the fruiting branch group, short and long shoots are cut off, short branches are promoted in the middle and lower parts of the branches, the bald phenomenon is changed, and the tree shape is compact. During the shaping stage, attention should be paid to the proper distance between the main branches in each layer of the shaping belt, so as not to cause the main branches of the big tree to be adjacent, resulting in the phenomenon of "neck", which is manifested by the over-flourishing of the lower main branches and the imbalanced growth of the upper main branches. At the same time, the interlayer distance must be opened according to the standard to improve the ventilation and light transmission conditions of the whole tree body. Adjacent arrangement of main branches is not only easy to cause "neck" and weak structure, but adjacent arrangement can avoid this disadvantage.

  4, the main and subordinate clear, balanced tree potential due to the distribution of branches on the tree by the top advantage and layer of the role of layered distribution, in terms of the whole tree or a backbone branch, the lower part (early formation) and the upper part (late formation) to maintain the size and height of the master-slave relationship. The first one is bigger and higher, and the second one is smaller and lower than it. From the tree body structure is stronger than the central trunk, the main branch is stronger than the lateral branches, the rest of the analogy, such a structure is clear, characterized by large branches in the lower, branchlets in the upper, branchlets light less, large branches by light more, good ventilation and light transmission, stable fruit position, tree structure rate solid, high and stable yield.