Special topic on dwarf and dense planting of apples (1): talk about the "dwarf" of dwarf anvil dense planting
Shi Jidong
Over the years, Apple's production management practice has made me deeply feel that the key to the smooth promotion of any technology lies not in the technology itself, but in the change of the concept of technology users. If the concept changes, the popularization of technology will be smooth; the concept remains unchanged, even if the technical essentials are mastered, the operation process may not be able to fully implement the technical plan. After communicating with the editorial department, I wrote down my feelings and thoughts on the cultivation and management of apple dwarf anvils in the past 10 years. An 8-part framework has been preliminarily formed, and it is planned to talk about technical practices, concepts and concepts from the perspectives of "dwarf", "anvil", "dense", "plant", "shape", "potential", "fertilizer" and "water", and communicate with fruit farmers and peers.
Figure 1 From sparse planting to dense planting of dwarf anvils
The apple planting pattern gradually developed from traditional sparse planting to dwarf anvil dense planting (Fig. 1).
Are you dwarfing?
Be.
Why do I see that the tree is quite tall?
This is a conversation I had with visitors when I received them in the orchard, and I realized that this "dwarf" is not simple, and it is not something that can be explained in one sentence. Nowadays, many fruit farmers are a little confused when building new orchards, and they can't decide whether to choose Qiaohua or dwarf. Below, I will try to start with the word "dwarf" and talk about my views and feelings on the dwarf cultivation of apples.
In apple tree cultivation, dwarfing does not refer to the height of the fruit tree. Put simply, dwarfing is measured by whether fruit trees are more likely to bear fruit or grow more easily. We refer to fruit trees with less vegetative growth and more reproductive growth as "dwarf" trees.
In long-term production practice, it has been found that grafting another non-apple "material" to fruit trees is easier to bear fruit, while at the same time reducing ineffective vegetative growth and increasing production efficiency. We call this "material" dwarf rootstock. An apple tree grafted with a dwarf rootstock is called a dwarf apple tree. Compared to ordinary (tree-changing) apple trees, dwarf apple trees are more conducive to fruiting, with less vegetative growth, a more compact tree body, and a smaller crown. The abundant results also further inhibited the vegetative growth of the fruit trees, and in the natural state, the size of the fruit trees we commonly use M9-T337 is about 35% of the tree size. In production, the height of the tree is controlled at about 3.3 m by plastic pruning.
Fuji apples, which are the most cultivated in our country, have strong vegetative growth and are not easy to flower and bear fruit, and people have summarized a variety of measures to promote their "dwarfing".
1) The rootstock is "short". The use of dwarf rootstock can promote the less vegetative growth of fruit trees, increase reproductive growth, and improve the production efficiency of fruit trees. This is the most thorough approach and the one that works once and for all. Common rootstocks include M26, M9-T337, G935, SH series, etc., and the common forms of dwarf in China include dwarf self-root rootstock (with special fibrous root system, see Figure 2) and dwarf intermediate rootstock.
Figure 2 Comparison of dwarfed root anvils and tree anvils
2) The variety is "short". Dwarfing is also good with short-branched varieties (Fig. 3), but the main problem is that the varieties are limited. The most successful domestic application is the Marshal short-branched varieties, such as Tianwang No. 1, Russian Dwarf No. 2, As, etc., and the Fuji series also has short-branched varieties, such as Refu No. 1, Miyazaki short-branched, Jin-18, etc.
Fig. 3 Fruiting of short-branched varieties
3) The tree shape is "short". "Gouute" plastic surgery or open heart shape (Fig. 4) is used. The nutrient transport path of fruit trees is artificially prolonged, which objectively has the effect of "dwarfing". The shape of the Guyute tree adopts the method of multiple leading trunks, which disperses the growth force of fruit trees and achieves the effect of "dwarfing".
Heart-shaped
Guyute plastic surgery
Figure 4 A tree shape with a dwarfing effect
4) Prune to "short". This is the approach that is currently commonly used. The main measures include thinning, angle opening, bud carving, branch pulling, circumcision, topping, etc. The main problem is that the workload is huge, the technical requirements are high, and it has to be carried out every year. Artificial pruning is shortening, With the shortage of labor and the aging of the population becoming more and more difficult to achieve, it is the main contradiction of fruit tree production at present, and it must be changed.
5) Breaking the root and causing "shortness". Through root pruning and root cutting (Fig. 5), the vegetative growth of fruit trees was inhibited and flowering was promoted. This measure is mainly used as an auxiliary control means for self-rooting fruit trees, and it is difficult to realize the tree tree.
Figure 5 Broken roots lead to dwarfing
6) Fertilizer and water cause "short". By increasing or decreasing the supply of fertilizer and water, adjusting the ratio of different nutrients, appropriately reducing the amount of nitrogen fertilizer, and increasing the amount of phosphorus and potassium fertilizer, the purpose of regulating tree potential can be achieved. This method has a slow effect and has a certain lag effect, which is different in different orchards, especially for arborvitae orchards, which is more difficult to grasp.
7) The load causes "short". By adjusting the load of fruit trees, the fruit is pressed to the crown, so as to achieve the purpose of controlling the excessive growth of fruit trees. This approach has limited effectiveness.
8) Hormones cause "shortness". The "dwarfing" effect was achieved by spraying plant growth regulators such as calcium cyclic acid (Figure 6). This method is technically demanding and not easy to master. Specific operation: During the inflorescence separation period of fruit trees, for the more prosperous fruit trees, spray 1 000 times of 15% calcium cyclic acid on the whole tree, and spray it again once at an interval of about 15 days as needed. Studies have shown that 1 spray can reduce the growth of new shoots by about 30%, and 2 sprays can reduce the growth of new shoots by more than 72% (as shown in Figure 6).
Fig. 6 Effect of spraying calcium cyclic acid to promote shortening
From the above analysis, it can be seen that the use of suitable dwarf rootstock is the fundamental measure to solve the problem. Many fruit farmers are greedy for cheap when building orchards, and use arbor seedlings to build orchards, embarking on a difficult road of production and operation—— — Long young tree period, closed before fruiting, a large number of pruning, branch cutting, closed garden transformation, happy falling, thinning...... We will repeat the same path of the previous generation of orchards, even if we don't care about the benefits of the orchard, unlike the previous generation of orchards, the growers are already old and simply cannot afford to go the same way again.
Under the current situation, when building a new orchard, we should first select the appropriate rootstock, give priority to the dwarf effect and production efficiency of the rootstock, and equip the rootstock combination and cultivation mode (tree shape), so that after the fruit tree is planted, it is easy to achieve the balance and stability of the tree potential (growth fruit) under the local fertilizer and water conditions, so as to greatly save labor costs and improve production efficiency.