Dwarf and close-planted orchards bear early fruits and have high yield. Once fertilizer and water are insufficient or improperly pruned, trees are prone to aging. Therefore, it is necessary to strengthen the comprehensive management of soil, fertilizer and water in order to play the role of pruning and maintain long-term economic benefits.
Dwarf and close-planted apple trees are characterized by short tree body, few main branches, low grade, fast growth and early fruiting. At present, in apple orchards with dwarfing rootstocks or dwarfing intermediate rootstocks, the tree height is generally about 2.5 meters, and the crown diameter and leaf curtain thickness are 2.0 ~ 3.0 meters. Most of the trees used in production are spindle-shaped or sparsely layered, with small crowns. The middle trunk is obvious, and the thickness difference between the middle trunk and the main branch is great. The branch angle of the main branch is large, and the middle branch bends upward, which is beneficial to restrain the upper strength and tree height. Dwarf trees have few branches, few layers, few layers, or no layers at all. Dwarf trees mainly develop in rows, so the row spacing should be greater than the plant spacing, and rectangular or strip planting should be adopted.
The characteristic of pruning dwarf fruit trees is to promote first and then control. That is, to promote its crown expansion, make it blossom and bear fruit early, and then control its suitable growth after bearing fruit, coordinate the relationship between growth and bearing fruit, and pay attention to the renewal of main branches and the alternate bearing of bearing branches. When pruning dwarf trees, we should pay attention to the combination of winter, spring and summer pruning, and the pruning method is mainly in the growth period.
The indicators of high-yield trees in dwarf close-planting apple orchards mainly include the following aspects:
(1) Suitable crown width Whether the crown width is suitable or not is related to the utilization rate of light energy, the time to enter the fruiting period, the yield and the efficiency of field operation. If the tree is too short, it will reduce the effective volume of the crown and reduce the fruit yield; If the tree is too tall, it can increase the fruit area, but the light condition is easy to get worse, which will also affect the yield and quality. Therefore, the suitable crown height should be determined according to site conditions, varieties, rootstocks, planting density and tree shape.
From the production practice, there is a close relationship between tree height and plant spacing. In a certain range of plant spacing, with the increase of plant spacing, the height of trees also increases, but it is not proportional. When the plant spacing is 3.5 meters, the tree height is also close to 3.5 meters, and the ratio of plant spacing to tree height is close to1; When the plant spacing is less than 3.5 meters, the tree height is greater than the plant spacing; When the plant spacing is more than 3.5 meters, the tree height is less than the plant spacing. According to the empirical formula, when the plant spacing is 1.0m, the tree height is about 2.2m; when the plant height is 2.0m, the tree height is about 2.9m; When the plant height is 3.0 meters, the tree height is about 3.4 meters; When the plant spacing is 4.0 meters, the height of the tree is about 3.8 meters.
In production, some orchards have too many branches left at the base of the crown, the growth is too large, the lateral growth is fast, the longitudinal growth is slow, the upper part is weak and the lower part is strong, which affects the yield and should be adjusted gradually.
(2) In the orchard, the uniformity of the orchard is positively correlated with the yield per unit area. Therefore, it is an important measure to improve the uniformity of orchard and maintain the order in the orchard.
The method to calculate the evenness of orchard is to divide all the fruit trees in an orchard into four grades according to the yield per plant, that is, high-yield trees are 3 grades, medium-yield trees are 2 grades, low-yield trees are 1 grade, and low-yield trees are 0 grades, and then calculate the evenness according to the number of trees in each grade. A large number of production statistics show that high quality and high yield can be guaranteed only if the uniformity of dwarf close-planted apple orchards reaches above 0.85.
(3) Appropriate crown volume Crown volume is directly related to fruit yield and quality. According to production statistics, the crown volume of sparse crown trees should not exceed 22,500 cubic meters per hectare; The volume of the crown per hectare of the dwarfed and densely planted orchard should be 15000 ~ 18000 cubic meters.
(4) The number of branches is suitable for actual production. It is difficult to obtain high yield due to insufficient branches per unit area, but it is impossible to obtain high yield due to too many branches per unit area, poor lighting conditions, insufficient development of branches and buds, large amount of ineffective branches and low nutrient accumulation. According to the experience of various apple producing areas, the yield is about 37,500 kg/ha, and the suitable number of branches is 654.38+200,000 ~ 654.38+800,000. Shandong institute of pomology's research results show that under the condition of close planting, when the yield of short-branched varieties of Marshal is 30,000-45,000 kg/ha, the suitable number of branches is 6,543.8+0.2 million -654.38+0.35 million/ha, and the maximum number should not exceed 6,543.8+0.5 million, otherwise, the cavity will be closed, and the lighting conditions will become worse, which will affect the quality and quality.
(5) Reasonable branch composition refers to the proportion of long, medium and short branches and leafy branches to the total branches. Branches with a general length of less than 5 cm, including foliage branches, are called short branches; Branches 5 ~ 15cm are called middle branches, and branches above 15cm are called long branches. Short and medium branches are the basis of results. Long branches grow for a long time, accumulate more nutrients, but consume more. Generally, the longer the branches, the more lush they grow; Too many long branches will also inhibit the flowering of lower branches and inner branches and aggravate physiological fruit drop; Short branches grow for a short time, produce less nutrients, but consume less themselves, which is beneficial to the nutrient accumulation and flower bud formation of trees. Therefore, in addition to paying attention to the total number of branches, we must also ensure appropriate branch analogy. According to the investigation, the ratio of long, medium and short branches is 1∶2∶7, which is a suitable branch analogy for high-yield trees. The pruning methods of adjusting branch analogy are: short cutting, increasing the proportion of long branches; Slow release, angular opening or bud carving can increase the proportion of short branches, which can be flexibly selected according to needs.
(6) Whether the amount of fruit left is appropriate directly affects the yield and quality. Within a certain quantitative range, the more fruits, the higher the yield. However, if there are too many fruits, the fruits will become smaller, the quality will decline, the yield may not be high, and it is easy to hang fruits in both years, which will weaken the growth of trees and lead to rot.
The experimental results show that the bearing capacity of trees is closely related to the thickness of trunk. Therefore, the suitable tree load can be determined according to the cross-sectional area of the trunk. According to the survey, the amount of fruit left per square centimeter of the trunk of high-yield apple trees is generally 0.4 ~ 0.6 kg. For example, a 6-year-old red Fuji has a stem circumference of 35 cm, and the amount of fruit left per square centimeter is 0.5 kg. When the insurance coefficient of fruit thinning and fruit setting is 1.05, the load per plant is 5 1.5 kg. According to the calculation of 5 fruits per kilogram, 258 fruits are left per plant. You can also use the equidistant fruit-keeping method, that is, leave 1 fruit every 20 cm or so. This method is simple and easy.
The way to check whether the amount of fruit left is appropriate is to check whether the weight of a single fruit meets the standard when harvesting in autumn. In general, the standard fruit weight of Jinguan and Starkrimson is180g; The standard of red Fuji with a single fruit weight of 200g is 150g. Under normal natural conditions, when the single fruit weight reaches or approaches the standard single fruit weight, it means that it is appropriate to keep the fruit and there is still the possibility of high yield in the next year; If the single fruit weight is obviously less than the standard single fruit weight, it means that there are too many leftover fruits, and the leftover fruits in the next year should be reduced appropriately; If the single fruit weight is obviously greater than the standard single fruit weight, it means that there is not enough fruit left, and the amount of fruit left should be increased appropriately in the second year.
Under normal circumstances, the fruit of young trees is generally large, and the fruit of mature trees is close to the standard single fruit weight; The fruit of the old tree is very small.
(7) Appropriate coverage rate, also called coverage rate, is the ratio of projected area of crown to occupied area of trees. Coverage is too large, ventilation and light transmission are poor, and management is inconvenient; The coverage rate is too small, and the utilization rate of land and light energy is low, which also affects economic benefits. In general, the coverage rate is 75% ~ 80%.
(8) The leaf area coefficient is moderate, that is, the ratio of the total leaf area per unit area to the area occupied by trees. The leaf area coefficient is generally 3.5 ~ 4.0.
(9) The suitable leaf-fruit ratio is the ratio of the number of leaves to the number of fruits. The suitable leaf-fruit ratio of apples is generally 30-40: 1, that is, in order to ensure the normal growth and development of1apples, 30-40 leaves are needed for nutrition, but there are great differences among different varieties: the leaf-fruit ratio of Guoguang is 30:1; Marshal system and golden crown system are 40 ∶1; The short anvil marshalling system is 35 ∶1; The suitable ratio of red Fuji apple is 50 ~ 70:1. The index range of suitable leaf-fruit ratio should be adjusted according to the maturity of varieties and the combination of varieties and rootstocks, but large and medium-sized fruits are different. Generally speaking, the suitable leaf-fruit ratio of early-maturing varieties should be greater than that of late-maturing varieties; The leaf-fruit ratio of rootstock and common variety should be about 1 times higher than that of short rootstock and short branch variety.
(10) The index of suitable branch-fruit ratio is expressed by the average number of branches per fruit. According to the investigation of high-quality and high-yield apple orchards by Yantai Fruit Research Institute, it is considered that the ratio of branches to fruits of main planted apples is 3 ~ 5. However, when the tree potential is different, the suitable range of branch-fruit ratio is also different. Generally, the weak tree is 4 and the strong tree is 2. According to the research of red Fuji apple by Liaoning Fruit Research Institute, the most suitable ratio of branches to fruits is 5∶ 1.
The suitable range of branch-fruit ratio is basically adapted to the suitable leaf-fruit ratio index. The average number of leaves on apple branches is generally 13 ~ 15. Thus, when the branch-fruit ratio is 3∶ 1, the leaf-fruit ratio can reach 39 ~ 45; When the branch-fruit ratio is 5∶ 1, the leaf-fruit ratio can be as high as 45 ~ 75. Compared with leaf-fruit ratio, branch-fruit ratio is simpler in production.
Attachment: Apple Yield Load Standard
1 Suitable load index
1. 1 branch-fruit ratio: based on the fruit, expressed by the average number of branches per fruit. At present, the suitable branch-fruit ratio of main apple varieties is 3 ~ 5 ∶ 1. Fuji, Daguoguang and other big fruit varieties, the ratio of branches to fruits is 5 ∶ 1. For medium fruit varieties, such as Guoguang, the ratio of branches to fruits should be 3 ~ 4: 1. The fruit setting rate of weak branches should be 4 ~ 5 ∶ 1, and that of strong branches should be 2 ~ 3 ∶ 1.
Leaf-to-fruit ratio of 1.2: based on the fruit, expressed by the average number of leaves per fruit. The suitable leaf-fruit ratio of apple varieties is 30 ~ 50:1. In this range, the leaf-fruit ratio of early-maturing varieties should be greater than that of late-maturing varieties; The suitable leaf-fruit ratio of large fruit varieties should be greater than that of small and medium fruit varieties. The suitable leaf-fruit ratio of rootstock and common variety should be about 1 times higher than that of short rootstock and short branch variety.
1.3 Calculate the yield according to the dry week: the appropriate fruit load of a complete fruit tree can be calculated according to the formula y = 0.05x2 0.25x, where Y is the appropriate load (kg) and X is the dry cycle (cm). When this formula is used to determine the appropriate load, it can be changed appropriately because of the tree potential.
1.3. 1 weak tree: the formula for calculating the appropriate load is y = 0.05x2-0.25x
1.3.2 mean tree: the formula for calculating the appropriate load is y = 0.05x2.
1.3.3 strong tree: the formula for calculating the appropriate load is y = 0.05x2+0.25x ..
1.3.4 Calculation of suitable load (see the table below)
attached table
Plan (continued)-1
Note: 1. This table is only applicable to large-scale fruit varieties with complete trees at the initial fruit stage and full fruit stage. The fruit retention of small fruit varieties is equal to the fruit yield multiplied by the number of fruits per kilogram. For example, Guoguang's fruit retention is equal to the fruit yield multiplied by 8 (one/kg).
2. There is no insurance factor for the remaining fruit quantity.
1.4 Calculate the yield according to the trunk cross-sectional area: measure the trunk circumference at the height of 1/2, and then calculate the trunk cross-sectional area according to the following formula:
Where s is the trunk area (square centimeter), L is the trunk circumference (centimeter), and π is the pi (3. 14). Then, the quotient obtained by dividing the actual fruit yield by the dry cross-sectional area is the fruit load expressed based on the dry cross-sectional area. The suitable fruit setting for fruit trees with moderate tree potential and general management level is 0.3 ~ 0.4 kg/cm2. Weak trees should be 0.3 kg/cm2, and strong trees should be 0.4 kg/cm2.
1.5 method of keeping fruit according to distance: 20 ~ 25cm, with a single big fruit and two small fruits, adjusted according to the strength of the tree.