Cultivation method for improving planting survival rate of dwarf-stock apple seedlings in northwest cold and arid regions

Abstract

The invention relates to the technical field of fruit tree cultivation, in particular to a cultivation method for improving the planting survival rate of dwarf-stock apple seedlings in northwest cold and arid regions. In autumn of the current year, before soil is frozen, soil preparation is conducted, planting furrows are dug, crop straw is laid at the bottoms of the planting furrows, a urea solution is sprayed, the dug soil and decomposed farmyard manure are mixed and then backfilled into the planting furrows, and irrigation and settling are conducted; in the spring of the second year, when the ground temperature of the 20-40 cm soil layer is higher than 8-10 DEG C, planting pits are dug in the planting furrows, and dwarf-stock apple seedlings and the like are planted in the planting pits. Aiming at the problem that the survival rate of newly-planted short-stock apple seedlings in spring is low due to the ecological characteristics of cold and drought of main apple producing areas in northwest high-altitude areas, an effective solution is provided, and the field planting survival rate of the transplanted short-stock apple seedlings is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of fruit tree cultivation, and particularly to a cultivation method for improving the survival rate of planted dwarf rootstock apple seedlings in the cold and arid regions of northwest China. Background Art

[0002] Apples are one of the most important fruits in the world. China is the main production area of apples in the world, and its planting area and output have ranked first in the world for many consecutive years. The apple industry is one of the most competitive agricultural products in the cold and arid characteristic agriculture of Gansu Province. The apple planting area in the whole province is stable at 5.8 million mu, ranking second in the country, with an annual output of 8.1 million tons and a output value of more than 60 billion yuan.

[0003] Gansu Province includes various climate types in alpine and arid regions, with complex terrain and geological structures and poor soil. The main apple production areas are mostly distributed in mountains, river valleys, and plateaus. "Cold", "continuous drought in winter and spring", "low ground temperature", and "low soil organic matter" together constitute the main obstacle factors for the high-quality development of dwarf rootstock cultivation in the modern apple industry, especially the main stress factors for the survival rate of dwarf rootstock apple seedlings planted in spring in cold and arid regions.

[0004] At present, the main reasons for the low survival rate of newly built modern dwarf rootstock apple orchards in the main apple production areas of Gansu Province are as follows: ① The seedlings carry diseases and viruses. ② The quality of the seedlings is poor and the roots are severely damaged. ③ The temperature and humidity are not properly controlled during the storage period of the seedlings. ④ Lack of treatment before planting the seedlings. ⑤ Improper management during the planting of the seedlings. ⑥ The exposed height of the dwarf rootstock is unreasonable. ⑦ Improper management after planting the dwarf rootstock seedlings. Due to the above factors, coupled with the frequent late frost damage and continuous drought in spring and summer in the northwest apple production area in recent years, it will accelerate the freezing and water loss of newly planted dwarf rootstock apple seedlings, and ultimately the seedlings will die due to frost damage and sprouting. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a cultivation method for improving the survival rate of planted dwarf rootstock apple seedlings in the cold and arid regions of northwest China. The present invention has an effective solution to the problem of low survival rate of newly planted dwarf rootstock apple seedlings in spring in the main apple production areas of high altitude regions in northwest China, and improves the survival rate of transplanted dwarf rootstock apple seedlings.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a cultivation method for improving the survival rate of planted dwarf rootstock apple seedlings in the cold and arid regions of northwest China, including the following steps:

[0008] 1) Prepare the land before the soil freezes in autumn of the current year, dig a planting trench, lay crop straw at the bottom of the planting trench, spray a urea solution, mix the excavated soil with decomposed farmyard manure and then backfill the planting trench, and irrigate and compact.

[0009] 2) In the spring of the second year, when the soil temperature at a depth of 20 - 40 cm is higher than 8 - 10 °C, dig planting holes on the planting trenches in step 1), and transplant dwarf rootstock apple seedlings into the planting holes;

[0010] Before transplanting, the dwarf rootstock apple seedlings are soaked in root and dipped in root in sequence;

[0011] The water used for soaking the roots contains 400 mg / L salicylic acid, 300 mg / L chitosan, 1.25 g / L white sugar, 0.45 g / L soybean flour, and 1.5 g / L vitamin B12;

[0012] The components for dipping the roots are carbendazim, superphosphate, fine soil, and water, and the mass ratio of carbendazim, superphosphate, fine soil, and water is 2:10.2:15:100;

[0013] The graft union of the dwarf rootstock apple seedlings is exposed 3 - 10 cm above the ground;

[0014] The standards for the dwarf rootstock apple seedlings are as follows: the seedling height is more than 1.2 m, the trunk diameter at 10 cm above the graft union is greater than 1.2 cm, there are more than 8 branches in the shaping zone with a length of 40 - 50 cm, more than 10 plump buds, distributed in a scattered manner, the main root is thick, there are many lateral roots, evenly distributed, the capillary roots are dense, there are more than 5 lateral roots with a diameter greater than 0.3 cm and a length exceeding 20 cm, and more than 10 lateral roots with a diameter greater than 0.2 cm and a length exceeding 20 cm, and many small and dense fibrous roots;

[0015] The dwarf rootstock apple seedlings include dwarf interstock apple seedlings or dwarf self-rootstock apple seedlings. The length of the dwarfing stock of the dwarf interstock apple seedlings is 25 cm, and the length of the rootstock of the dwarf self-rootstock apple seedlings is 20 cm;

[0016] The varieties of the rootstocks of the dwarf rootstock apple seedlings are Fuji, Yuhua, New Red Star, Honeycrisp, Short Branch Fuji, Gala, Golden Delicious, Granny Smith, Jonathan, or Pink Lady;

[0017] When the altitude is higher than 1500 m, short - cut pruning is carried out on the dwarf rootstock apple seedlings after they have survived the transplanting.

[0018] Preferably, the width and depth of the planting trench are both 0.8 - 1 m;

[0019] The laying thickness of the crop straw is 10 - 20 cm. The crop straw includes wheat straw, and the length of the crop straw is preferably 10 - 20 cm;

[0020] The mass percentage content of the urea solution is 0.5%;

[0021] The usage amount of the urea solution is 20 L per mu;

[0022] The types of the well-rotted farmyard manure include well-rotted sheep manure, and the application rate is 10-20 m 3 / mu.

[0023] Preferably, when the dwarfing rootstock apple seedlings in step 2) are dwarfing interstock apple seedlings, the planting hole is 60 cm square;

[0024] When the dwarfing rootstock apple seedlings are dwarfing self-rooted apple seedlings, the planting hole is 40 cm square.

[0025] Preferably, when the dwarfing rootstock apple seedlings in step 2) are dwarfing interstock apple seedlings, the row spacing is 1.5-2 m×4 m, and the transplanting density is 84-110 plants / mu;

[0026] When the dwarfing rootstock apple seedlings are dwarfing self-rooted apple seedlings, the row spacing is 1-1.2 m×3.5 m, and the transplanting density is 158-190 plants / mu.

[0027] Preferably, the time for root dipping in step 2) is 24-48 h.

[0028] Preferably, when the rootstock variety of the dwarfing rootstock apple seedlings in step 2) is Fuji or Yuhua variety, the distance from the graft union to the ground is 8-10 cm;

[0029] When the rootstock variety is Starkrimson, Honeycrisp, Dwarf Fuji or Gala, the distance from the graft union to the ground is 3-5 cm;

[0030] When the rootstock variety is Golden Delicious, Granny Smith, Jonathan or Pink Lady, the distance from the graft union to the ground is 5-8 cm.

[0031] Preferably, when the dwarfing rootstock apple seedlings in step 2) cannot be transplanted immediately, they are stored, and the storage temperature is 0.5-1.5 °C, the humidity is above 95%, and the time does not exceed 10 d.

[0032] Preferably, the standards for short pruning in step 2) are as follows: the central leader and the main branches with a length of no more than 10 cm are not pruned, the tips of the main branches with a length of 10-50 cm are short-pruned by 5-10 cm, the main branches with a length exceeding 50 cm are short-pruned to 50 cm, the branches with an angle within 30° and competing with the central leader are removed with 10 cm left at the base, the main branches below 60 cm from the ground of the central leader are directly removed, and the mechanically damaged, broken and dried branches are short-pruned to the healthy part.

[0033] The beneficial effects of the present invention:

[0034] 1. The fundamental way to improve the survival rate of apple seedling planting is the rootstock and variety of the seedlings, so as to achieve suitable planting in suitable places. Compared with other apple rootstocks such as SH series, Pingyi sweet tea, and Hebei rootstock series, M series and B series rootstocks have strong cold resistance and drought resistance.

[0035] 2. The planting time of apple seedlings varies greatly depending on the different altitudes, regions, and climates in apple-producing areas across the country. In the production areas of Shandong, Hebei, and Shanxi, due to the relatively rapid rise in air temperature and soil temperature and the earlier phenological period, the planting time of apple seedlings can be 7 - 10 days earlier than that in the northwestern Gansu production area. In early April in the Gansu production area, although the air temperature rises relatively quickly, the soil temperature rises slowly. When the soil temperature is lower than 8°C, if the root system of the seedlings has pruning wounds, its function cannot be restored in a timely manner. However, above-ground parts of the seedlings have already started to fully flow with sap under the condition of high air temperature. This will cause the above-ground parts of the tree to accelerate water evaporation, while the underground roots cannot absorb water and fertilizer in a timely manner to supply the life activities of the above-ground tree body. Moreover, in spring in the northwest, there are many winds, which will further accelerate the loss of water in the above-ground parts of the tree. As a result, the tree body will dry out and die.

[0036] 3. In many production areas across the country, when digging planting trenches and holes before planting apple seedlings, well-rotted farmyard manure is added and mixed with the soil before planting the seedlings. This method of improving the soil while planting trees is not advisable in the high-altitude, cold and cool apple production areas in the northwest. Because the decomposition and transformation of fertilizers and their timely absorption by the tree body require relatively high soil temperature and soil moisture. When planting trees in the high-altitude, cold and cool apple production areas in the northwest, watering can be carried out in a timely manner, but the local soil temperature is already relatively low, and watering will further reduce the soil temperature, making it impossible to fully decompose the fertilizers. When the newly planted seedlings are recovering, this will cause the root system of the seedlings to be burned to death, and then the seedlings will die.

[0037] 4. In many production areas across the country, before planting apple seedlings, the seedlings are soaked in water. During planting, they are instantaneously sterilized with low-concentration lime sulfur aqueous solution, thiophanate-methyl wettable powder, 100-fold 21% peracetic acid aqueous solution and other agents and then directly planted. However, this cannot ensure good sterilization and root-promoting effects when the apple seedlings are fully hydrated. In the method of the present invention, salicylic acid, chitosan, white sugar, soybean flour, and vitamin B12 are added to the water for soaking the roots of the seedlings. Salicylic acid is a small-molecule phenolic substance widely present in higher plants. It is widely used to alleviate low-temperature stress in plants and also has the effects of increasing the root-shoot ratio and promoting the formation and growth of lateral root primordia. The application of exogenous salicylic acid can promote the generation of lateral root primordia, root growth, and root activity in plants under environmental stress. Salicylic acid can also play a role in improving the resistance of plants and regulating the absorption and utilization of various nutrients by plants in adversity; chitosan is an amino polysaccharide polymer with good film-forming and antibacterial functions. At the same time, because it contains rich C and N elements, it can be degraded and utilized by microorganisms as nutrients for plant growth. Chitosan also has the ability to cement soil particles and promote the formation of soil aggregates, making the formed aggregates water-stable. The most important point is that chitosan can promote root development, increase the number of root hairs, fibrous roots, and secondary roots, thereby enhancing the fertilizer and water absorption capacity of plants. Vitamin B12 also has the effect of promoting plant rooting. White sugar can be used as a nutrient for the growth of plant roots and the reproduction of rhizosphere microorganisms. Soybean flour carries various nutrients to promote film formation on the root surface.

[0038] In the method of the present invention, after the seedlings are soaked well, they are dipped in a slurry of 50-fold solution of 80% carbendazim wettable powder + 5-10% superphosphate + fine soil (i.e., 80% carbendazim, superphosphate, fine soil and water, and the mass ratio of carbendazim, superphosphate, fine soil and water is 2:10.2:15:100). This can not only reduce the water loss of the roots when planting apple seedlings in the arid northwest apple production area and maintain the activity of the seedlings, but also the added superphosphate can moderately provide nutrients for the roots of the seedlings. The reason for dipping the roots in the form of slurry is that the slurry can store water while carrying fertilizer, protect the roots, and thus promote the growth of the new shoots of the seedlings.

[0039] 5. The planting depth of dwarf seedlings is not fixed. It should be appropriately adjusted according to different factors such as the region, climate, altitude, orchard terrain conditions, and variety growth potential in apple production areas across the country.

[0040] 6. In many orchards with warm climate, low altitude, and good water and fertilizer conditions, pruning is carried out at the same time as planting dwarf apple seedlings. This is not suitable for mountain orchards in the northwest apple production area with an altitude higher than 1500m and relatively cold climate. It is recommended to carry out short pruning on the seedlings after the seedlings have recovered from transplantation.

[0041] By achieving the above six differences, the survival rate of dwarf rootstock apple seedlings planted in the cold and arid regions of Northwest China can be effectively improved.

[0042] In the present invention, ① an appropriate and scientific planting time of seedlings suitable for the cold and arid regions of Northwest China is determined, and moderate soil improvement before planting is carried out, which reduces the risks of root freezing, drying out, and root burning and seedling death; ② for the treatment method of seedlings before planting, mainly on the basis of fully disinfecting and sterilizing the seedlings, especially the roots of the seedlings, the root activity is improved, promoting the rapid recovery of root activity after the seedlings are planted, shortening the seedling-slowing time, reducing the risk of the aerial part of apple seedlings drying out, and improving the survival rate of seedlings; ③ regarding the planting depth of seedlings, according to different altitudes, different terrains, different orchard management conditions, and different rootstock-scion combinations, different planting depths of seedlings are determined, which can effectively adjust the growth trend of seedlings after planting and improve the survival rate of seedlings; ④ regarding the management after seedlings are planted, in addition to the aspects that are more consistent with the conventional planting methods, for whether to perform topping pruning during planting or after the seedlings have slowed down, this invention patent gives different solutions according to different situations. In the apple production areas in the cold and arid regions of Northwest China, most of the high-quality apple orchards are high-altitude mountain orchards. Then, for mountain orchards with an altitude higher than 1500m and relatively cold and cool climates, it is recommended to perform short pruning on the seedlings after they have slowed down to prevent pruning during planting, which may cause injuries to both the roots and the aerial parts. Moreover, since it takes a certain amount of time for the roots to recover their vitality, it will inevitably affect the trend of sap flow and increase the risks of apple seedlings losing water, drying out, and dying. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the embodiments.

[0044] Figure 1 Diagram of the seedlings of the cultivation method in Example 1;

[0045] Figure 2 Vertical 0 - 20 cm soil layer temperature on a cloudy day in Example 1 (April 30, 2024);

[0046] Figure 3 Vertical 20 - 40 cm soil layer temperature on a cloudy day in Example 1 (April 30, 2024);

[0047] Figure 4 Vertical 40 - 60 cm soil layer temperature on a cloudy day in Example 1 (April 30, 2024);

[0048] Figure 5 Modern dwarf rootstock apple demonstration orchard in Yuwan Village, Yuwan Township, Example 2;

[0049] Figure 6Soil temperature of the 0-20 cm vertical soil layer on a sunny day in Example 2 (May 5, 2024);

[0050] Figure 7 Soil temperature of the 20-40 cm vertical soil layer on a sunny day in Example 2 (May 5, 2024);

[0051] Figure 8 Soil temperature of the 40-60 cm vertical soil layer on a sunny day in Example 2 (May 5, 2024);

[0052] Figure 9 Modern dwarf rootstock apple demonstration orchard in Dazhuang Village, Zhiping Town in Example 3;

[0053] Figure 10 Soil water content of the 0-20 cm vertical soil layer in Example 3 (May 2, 2024);

[0054] Figure 11 Soil water content of the 20-40 cm vertical soil layer in Example 3 (May 2, 2024);

[0055] Figure 12 Soil water content of the 40-60 cm vertical soil layer in Example 3 (May 2, 2024);

[0056] Figure 13 Dead seedling situation of apple seedlings in the conventional planting method in Example 1;

[0057] Figure 14 Healthy growth situation of apple seedlings in the planting method of Example 1 of the present invention;

[0058] Figure 15 Comparison photos of the roots of dwarf rootstock apple seedlings planted by the conventional planting method in Example 1 and the planting method of Example 1 of the present invention. Detailed implementation manners

[0059] The present invention provides a cultivation method for improving the survival rate of dwarf rootstock apple seedlings planted in the cold and arid regions of northwest China, comprising the following steps:

[0060] 1) Prepare the land before the soil freezes in autumn of the current year, dig a planting trench, spread crop straw at the bottom of the planting trench, spray urea solution, mix the excavated soil with well-rotted farmyard manure and then backfill the planting trench, and irrigate to compact;

[0061] 2) In the spring of the second year, when the soil temperature of the 20-40 cm soil layer is higher than 8-10 °C, dig planting holes on the planting trench in step 1), and transplant dwarf rootstock apple seedlings into the planting holes;

[0062] The dwarf rootstock apple seedlings are subjected to root soaking and root dipping in sequence before transplantation;

[0063] The water used for root soaking contains 400 mg / L of salicylic acid, 300 mg / L of chitosan, 1.25 g / L of white sugar, 0.45 g / L of soybean flour, and 1.5 g / L of vitamin B12;

[0064] The components for root dipping are carbendazim, superphosphate, fine soil, and water, and the mass ratio of carbendazim, superphosphate, fine soil, and water is 2:10.2:15:100;

[0065] The grafting joint of the dwarfing rootstock apple seedlings is exposed 3 - 10 cm above the ground;

[0066] The standards for the dwarfing rootstock apple seedlings are as follows: the seedling height is above 1.2 m, the trunk diameter at 10 cm above the grafting joint is greater than 1.2 cm, there are more than 8 branches within the shaping zone of 40 - 50 cm in length, more than 10 plump buds, distributed staggeredly, the main root is thick, there are many lateral roots, evenly distributed, the capillary roots are dense, there are more than 5 lateral roots with a diameter greater than 0.3 cm and a length exceeding 20 cm, more than 10 lateral roots with a diameter greater than 0.2 cm and a length exceeding 20 cm, and many small and dense fibrous roots;

[0067] The dwarfing rootstock apple seedlings include dwarfing interstock apple seedlings or dwarfing self - rootstock apple seedlings. The length of the dwarfing interstock of the dwarfing interstock apple seedlings is 25 cm, and the length of the rootstock of the dwarfing self - rootstock apple seedlings is 20 cm;

[0068] The varieties of the rootstocks of the dwarfing rootstock apple seedlings are Fuji, Yuhua, New Red Star, Honeycrisp, Short - branch Fuji, Gala, Golden Delicious, Granny Smith, Jonathan, or Pink Lady;

[0069] When the altitude is higher than 1500 m, short - cut pruning is carried out on the dwarfing rootstock apple seedlings after the seedlings have recovered from transplanting.

[0070] In the present invention, land preparation is carried out before the soil freezes in autumn of the current year, a planting trench is dug, crop straw is laid at the bottom of the planting trench, a urea solution is sprayed, the excavated soil is mixed with decomposed farmyard manure and then backfilled into the planting trench, and water is irrigated to compact. In the present invention, the width and depth of the planting trench are both preferably 0.8 - 1 m. In the present invention, the laying thickness of the crop straw is preferably 10 - 20 cm, the crop straw includes wheat straw, and the length of the crop straw is preferably 10 - 20 cm. In the present invention, the mass percentage content of the urea solution is 0.5%. In the present invention, the usage amount of the urea solution is 20 L / mu. In the present invention, the types of the decomposed farmyard manure preferably include decomposed sheep manure, and the application amount is preferably 10 - 20 m 3 / mu.

[0071] In the present invention, when the dwarfing rootstock apple seedlings are semi-dwarfing rootstock apple seedlings, the planting hole is preferably a square with a side length of 60 cm; when the dwarfing rootstock apple seedlings are self-rooted dwarfing rootstock apple seedlings, the planting hole is preferably a square with a side length of 40 cm.

[0072] In the present invention, the dwarfing rootstock apple seedlings need to select rootstocks suitable for planting in high-altitude cold and arid areas, such as M-series and B-series rootstocks. The seedlings should be healthy and free from diseases and viruses. It is recommended to select high-quality virus-free large seedlings that have been continuously cultivated in the nursery for 2 - 4 years and have been headed and shaped, with reasonable branches. The bud bodies should be plump, the roots should be developed, the grafting part should be well-healed, without mechanical damage and pests and diseases, so as to ensure that the seedlings can bear fruit in the second year and have a high yield in the third year after being planted in the same year. Standards for high-quality dwarfing rootstock seedlings: The seedling height is above 1.2 - 1.5 m. The lengths of the dwarfing rootstock of the semi-dwarfing rootstock and the self-rooted dwarfing rootstock are 25 cm and 20 cm respectively. The trunk diameter at 10 cm above the grafting joint of the seedling variety is greater than 1.2 cm; there are more than 8 branches and more than 10 plump buds in the shaping zone with a length of 40 - 50 cm, which are distributed in a staggered manner. The main root is thick, there are many lateral roots, which are evenly distributed, and the capillary roots are dense. There are more than 5 lateral roots with a diameter greater than 0.3 cm and a length exceeding 20 cm; there are more than 10 lateral roots with a diameter greater than 0.2 cm and a length exceeding 20 cm, and there are many small and dense fibrous roots. The present invention does not have special limitations on the grafting method, and conventional methods can be adopted. For example, for the grafting method: Collect one-year-old branches of the variety, with an average diameter of 1 cm. Among them, the scions collected during the winter dormancy period need to be soaked, wrapped with plastic wrap, and stored in a freezer at 0 - 4 °C for later use in grafting in March. The grafting method adopts inlay budding. At 20 - 25 cm above the root of the rootstock, two-knife method is used to cut out an inclined cut at about 45 degrees, presenting a shield-shaped cut. Similarly, on the plump bud point of the scion, take a shield-shaped bud piece that can completely fit the shield-shaped cut of the rootstock. The scion is also cut with the two-knife method in the same direction to cut out a bud piece with the same slope. Insert the bud piece into the cut of the rootstock. After aligning the cambiums on both sides of the rootstock and the bud piece, expose the bud point, and tie the remaining positions of the bud piece tightly with a grafting tape to avoid dislocation.

[0073] In the present invention, it is preferable to protect the roots of apple seedlings during transportation, storage and planting to reduce damage. During the transportation and storage of seedlings, protect the roots and branches of the seedlings well to prevent problems such as damage, dehydration and freezing of the seedlings. Before planting, the roots can be appropriately pruned, mainly pruning some cracked roots, or some broken roots and overlong roots, but the pruning should not be too heavy. If the roots in the underground part are small, the branches with too thick branches can be removed by leaving a short stub of 2 - 4 cm. During the planting process, carefully check the roots and prune the damaged parts. If there is no soil attached to the roots of the seedlings, they need to be dipped in mud before planting.

[0074] In the present invention, it is preferable to scientifically set the temperature and humidity conditions of the cold storage for apple seedlings. After the seedlings are out of the nursery, if they cannot be transported immediately or cannot be planted immediately after transportation, they should be immediately stored in the cold storage. The temperature in the cold storage is 0.5 - 1.5°C, and the humidity is above 95%. Pay attention to monitoring the temperature and humidity in the cold storage at any time. If the temperature is lower than -5°C, after long-term storage of dwarf seedlings, the roots will be damaged by freezing and cannot grow normally. For the temporary storage of seedlings, the time should not exceed 10 days. The roots of the seedlings can be moisturized with sand, sawdust, straw, or straw curtains. It is necessary to regularly check the humidity of the sandy soil and the seedlings. Generally, the sandy soil is replenished with water once every 10 - 15 days, and the sunshade net is sprinkled with water once every 2 - 3 days. Ordinary seedlings and virus-free seedlings should be stored separately.

[0075] In the present invention, for the reasonable planting time of apple seedlings in the northwest apple production area, in the cold and arid regions of the northwest plateau, the ground temperature in early spring rises slowly, slower than the rate of air temperature rise. Planting should be carried out after the ground temperature at a depth of 20 cm is stably higher than 8 - 10°C. Taking Jingning County, Pingliang City, Gansu Province as an example, it is approximately after April 15.

[0076] In the present invention, soil treatment before planting apple seedlings: Prepare the land before the soil freezes in autumn. First, level the soil before preparing the land. Dig a planting ditch with a width and depth of 0.8 - 1.0 m according to the planned planting row. Lay a layer of crop straw 10 - 20 cm thick at the bottom of the ditch, and spray 0.5% urea solution to promote the decomposition of the straw. Mix the excavated soil with 10 - 20 m 3 / mu of decomposed farmyard manure, mix well and backfill the planting ditch, then irrigate and compact it to prepare for tree planting in the following year. In the following spring, mark points with lime according to the planned plant spacing. For the planting of dwarf self-rootstock seedlings, dig a planting hole with a side length of 40 cm, and for the planting of dwarf interstock seedlings, dig a planting hole with a side length of 60 cm.

[0077] In the present invention, attention should be paid to the sterilization and root-promoting treatment before planting apple seedlings. Before planting the seedlings, carefully check whether there are dry rot disease spots above and below the graft union, and use pruning shears to cut the lateral roots to check for any lesions such as brown discoloration. The trimmed seedling roots should be fully soaked in water for 24 - 48 h. To ensure better root growth and seedling establishment and prevent the infection of pathogenic bacteria and viruses after planting the seedlings, add the following components to the water for soaking the roots: 400 mg / L salicylic acid, 300 mg / L chitosan, 1.25 g / L white sugar, 0.45 g / L soybean flour, 1.5 g / L vitamin B12. After the seedlings are soaked, dip the roots in a slurry of 50 times the wettable powder of 80% carbendazim + 5 - 10% superphosphate + fine soil (i.e., 2 kg of 80% carbendazim wettable powder + 10.2 kg of superphosphate + 15 kg of fine soil + 100 L of water) to reduce water loss from the roots and maintain the activity of the seedlings, and then plant immediately after treatment.

[0078] In the present invention, for the planting of dwarfing rootstock apple seedlings, when establishing an orchard with dwarfing self-rootstock seedlings, the row and plant spacing is 1 - 1.2 m × 3.5 m, and 158 - 190 plants are planted per mu. When establishing an orchard with dwarfing interstock seedlings, the row and plant spacing is 1.5 - 2 m × 4 m, and 84 - 110 plants are planted per mu. The specific row and plant spacing setting also needs to be determined according to the scion-rootstock combination. For varieties with stronger growth vigor such as Fuji and Yuhua Zaofu, the plant spacing can be appropriately increased, while for varieties with weaker growth vigor such as Gala, Honeycrisp, and Spur Fuji, the plant spacing can be appropriately decreased. When planting, place the seedlings into the planting holes, make the root systems evenly distributed, keep the grafting unions facing in the same direction, straighten the seedlings, align the rows and plants, and the seedlings should be no more than 15 cm away from the lattice fiber poles. Backfill fine soil around the root systems until all the root systems are covered, then lift the seedlings to straighten the root systems and tamp them down. Pour 20 - 30 kg of water into the planting holes. When half of the water has infiltrated, immediately fill the holes with fine soil while correcting the planting position. When the root collar is buried, gently step on it and sprinkle a layer of fine soil. The settling water must be thoroughly watered. For orchards with drip irrigation conditions, 8 - 10 cubic meters of water can be watered per mu before planting. After planting the seedlings, 18 - 20 cubic meters of water are watered per mu. After 7 - 10 days, 8 - 10 cubic meters of water are watered per mu. After planting, fix the seedlings on the first and second steel wires with buckles to prevent the seedlings from lodging due to watering and wind. Level the tree rows into a trough shape, and cover the tree basins with black film or black geotextiles to collect rainwater, conserve soil moisture, increase soil temperature, inhibit weeds, save nutrients, promote the recovery and rapid growth of the root systems, and shorten the seedling-slowing period. The coverage width is 1 - 1.5 m, in a funnel shape with the center low and the perimeter high, fixed with ground nails, and the two sides are compacted with soil, with a height difference of about 5 cm. Natural grass can grow in the inter-row spaces or clover, hairy vetch, ryegrass, etc. with extremely low stem lignification degree and low water consumption can be planted. After the grass grows to 30 - 40 cm in height, it is mowed and covered on the tree basins.

[0079] In the present invention, the planting depth of dwarf rootstock apple seedlings needs to be reasonable. In the process of applying the apple dwarf rootstock close planting technology, the dwarfing effect is mainly achieved by using the dwarfing rootstock. In this process, the length of the dwarfing rootstock can greatly affect the dwarfing effect of apple trees. In the actual planting process, it is not difficult to find that there is a close relationship between the size of the apple tree crown and the depth of the M-series and B-series dwarfing rootstocks buried in the soil. If the dwarfing rootstock is buried too deep, roots will grow during contact with the soil, and its growth trend will be too strong, gradually changing from dwarfing to arborization. If the dwarfing rootstock is buried too shallow, it will be exposed on the soil surface, which will, to a certain extent, enhance the dwarfing effect, but the growth and development of young trees will be slow, and eventually they will tilt. Facing this situation, it is necessary to reasonably control the depth of the dwarfing rootstock buried in the soil during the planting of young trees, and note that once the variety takes root, it will lead to the failure of orchard establishment. Generally, the planting depth is such that the graft union of the rootstock and the variety is about 4 - 10 cm above the ground, and the height of the graft union from the ground also varies depending on the variety. For varieties with stronger growth such as Fuji and Yuhua Zaofu, the distance from the graft union to the ground can be controlled at 8 - 10 cm; for varieties with weaker growth such as Starkrimson, Honeycrisp, Spur Fuji, and Gala, the distance from the graft union to the ground can be controlled at 3 - 5 cm; and for varieties with medium growth such as Golden Delicious, Granny Smith, Jonathan, and Pink Lady, the distance from the graft union to the ground can be controlled at 5 - 8 cm. Secondly, in dry orchard areas with cool climates, the tree vigor is generally weak, and the distance of the rootstock exposed above the ground can be appropriately reduced to 5 - 10 cm; in orchards with warm climates and high soil humidity, the tree grows too vigorously, and the distance of the rootstock exposed above the ground can be appropriately increased by 15 - 20 cm.

[0080] In the present invention, for the post-planting management of dwarf rootstock apple seedlings, for 3-year-old high-quality seedlings with plump buds, the trunk diameter at 10 cm above the variety interface at the base of the seedling is above 1 - 1.3 cm, and the seedling height is above 1.5 m. When planting, no tree topping is required, but large branches with a branch thickness greater than 2 / 3 of the trunk thickness at the same position, or branches with an angle within 30° are removed by leaving a 2-cm short stub. If the trunk diameter of the seedling is less than 1 cm, tree topping is carried out in a timely manner at a plump bud after planting. The general tree topping height is 80 cm, and the buds within 10 cm below the pruning cut are removed to prevent the emergence of competing branches that affect the growth of the top shoot. The pruning cut is promptly protected with pruning sealer or Flumorph, or the seedling is bagged with a plastic bag made of agricultural film, which can prevent water loss and freeze damage. If the growth of the seedling is not strong in the second year and subsequent years, tree topping must be continuously carried out.

[0081] After the seedling is topped, a 5-cm-wide plastic tube film is used to cover the trunk of the seedling, and the root neck of the seedling is compacted with soil to prevent air leakage. The tube film is twisted several times along the seedling to reduce the voids inside the tube film and prevent the tube film from being blown apart by strong winds. The upper part of the tube film is tightly tied. When the buds on the seedling grow to 2 - 3 cm after germination, the tube film opening is promptly untied for ventilation. After adapting to the external environment for 7 days, the tube film is removed on a cloudy day. Alternatively, the plastic mulch can be cut into 10-cm-wide strips and wrapped around the trunk from bottom to top, which also has the effect of maintaining moisture. For seedlings with lateral branches, the plastic mulch is more practical.

[0082] For mountain orchards with an altitude above 1500m and relatively cold and cool climate, it is recommended to carry out short pruning on the seedlings after the seedlings have recovered from transplanting. The principle is not to prune the central trunk and the main branches with a length of less than 10cm. For the main branches with a length of 10 - 50cm, the tips are short-pruned by 5 - 10cm. For the main branches with a length exceeding 50cm, they are short-pruned to 50cm. For the branches with an angle within 30° and competing with the central trunk, 10cm is left at the base and they are removed. The main branches below 60cm from the ground of the central trunk are directly removed. The mechanically damaged, broken and dried branches are short-pruned to the healthy part.

[0083] When the buds at the top of the branches begin to swell, methods such as bud notching or applying shoot-promoting agent can be adopted to improve the sprouting rate. For the extended branch of the central trunk, starting from the base, select a bud with a suitable direction every 15 - 20cm, and notch the cortex 0.5cm above the bud, or apply the shoot-promoting agent on the bud. For the lateral branches, start from 10cm away from the main trunk and carry out bud notching or apply the shoot-promoting agent on the lateral and back buds at 3 / 4 of the total length of the branches.

[0084] To further illustrate the present invention, the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0085] Embodiment 1

[0086] The planting method of this invention patent:

[0087] 1. Seedling quality:

[0088] The rootstock is M9T337 self-rootstock, the seedling height is above 1.5m, the rootstock length of the dwarf self-rootstock is 20cm, and the trunk diameter at 10cm above the grafting joint of the seedling variety is greater than 1.2cm; there are more than 8 branches and more than 10 plump buds in the shaping zone with a length of 40 - 50cm on the main trunk of the seedling, which are distributed in a scattered manner. The main root is thick, there are many lateral roots, which are evenly distributed, and the capillary roots are dense. There are more than 5 lateral roots with a diameter greater than 0.3cm and a length exceeding 20cm; there are more than 10 lateral roots with a diameter greater than 0.2cm and a length exceeding 20cm, and there are many small and dense fibrous roots.

[0089] 2. Seedling transportation and preservation:

[0090] During the transportation and storage of seedlings, protect the roots and branches of the seedlings well to prevent problems such as damage, dehydration, and freezing injury of the seedlings. Before planting, the roots can be appropriately pruned, mainly pruning some cracked roots, or some broken roots and overly long roots, but the pruning should not be too heavy. If the underground roots are relatively small, branches that are too thick can be removed by leaving a short stub of 2 - 4 cm. During the planting process, carefully check the roots and prune the injured parts. If there is no soil attached to the roots of the seedlings, they should be planted after dipping in mud. After the seedlings are out of the nursery, if they cannot be transported immediately or cannot be planted immediately after transportation, they should be immediately stored in a cold storage. The temperature in the cold storage is 1°C and the humidity is over 95%. For the temporary storage of seedlings, the time should not exceed 10 days, and the roots of the seedlings can be moisturized with sand, sawdust, straw, and straw curtains. It is necessary to regularly check the humidity of the sand and the seedlings. The sand is replenished with water once every 10 days, and the sunshade net is sprinkled with water once every 2 days.

[0091] 3. Seedling planting time:

[0092] In the cold and arid regions of the northwest plateau, the ground temperature rises slowly in early spring, slower than the rising speed of the air temperature. Planting should be carried out after the ground temperature of the 20 - cm soil layer is stably higher than 8 - 10°C. Taking Jingning County, Pingliang City, Gansu Province as an example, it is approximately after April 15.

[0093] 4. Soil treatment before seedling planting:

[0094] Prepare the land before the soil freezes in autumn. Level the soil before preparation. Dig a planting ditch with a width and depth of 0.8 m according to the planned planting row. Spread wheat straw with a thickness of 20 cm at the bottom of the ditch, and spray 0.5% urea solution (the application rate is 20 L / acre) to promote the decomposition of the straw. Mix the excavated soil with 20 m³ / acre of well - decomposed farmyard manure, and then backfill the planting ditch after mixing evenly. Irrigate and let it settle to prepare for tree planting in the following year. In the spring of the following year, mark points with lime according to the planned plant spacing, and dig a planting hole with a side length of 50 cm for dwarfing self - rootstock seedlings.

[0095] 5. Seedling sterilization and root - promoting treatment:

[0096] Before planting the seedlings, carefully check whether there are dry rot disease spots above and below the grafting interface, and use pruning shears to cut lateral roots to check for pathological changes such as turning brown. The trimmed roots of the seedlings should be fully soaked in water for 48 h. To ensure better rooting and seedling recovery after planting and prevent the invasion of pathogenic bacteria and viruses, add the following components to the water for soaking the roots: 400 mg / L salicylic acid, 300 mg / L chitosan, 1.25 g / L white sugar, 0.45 g / L soybean flour, 1.5 g / L vitamin B12. After the seedlings are soaked, dip the roots in a slurry of 50 - fold liquid of 80% carbendazim wettable powder + 5 - 10% superphosphate + fine soil (2 kg of 80% carbendazim wettable powder + 10.2 kg of superphosphate + 15 kg of fine soil + 100 L of water) to reduce water loss from the roots and maintain the activity of the seedlings, and plant immediately after treatment.

[0097] 6. Seedling planting method:

[0098] Use dwarf self-rooted rootstock seedlings to build a garden, with a row spacing of 1.2m×3.5m, and 158 plants per mu. When planting, place the seedlings in the planting hole to make the root system evenly distributed, keep the grafting point in the same direction, straighten the seedlings, align the rows, and keep the seedlings no more than 15cm away from the fiber poles of the grid. After backfilling the fine soil around the root system to the entire root system, lift the seedlings to stretch the root system and tamp them down. Pour 30kg of water into the planting hole. When 1 / 2 of the water seeps down, immediately fill the hole with fine soil, and correct the planting position at the same time. When the root neck is buried, gently tread it and sprinkle a layer of fine soil. The planting water must be sufficient and thorough. For orchards with drip irrigation conditions, 10 cubic meters per mu of water can be used before planting. Water 20 cubic meters per mu after planting the seedlings, and 10 cubic meters per mu after 10 days. After planting, use buckles to fix the seedlings on the first and second steel wires to prevent watering and wind from causing the seedlings to fall over. The tree rows are leveled into a trough shape, and the tree trays are covered with black film or black ground cloth to collect rainwater and retain moisture, increase ground temperature, suppress weeds, save nutrients, promote root recovery and rapid growth, and shorten the seedling acclimatization period. The covering width is 1.5m, and it is a funnel shape with a low center and high surroundings. It is fixed with ground nails and compacted with soil on both sides. The drop is about 5cm. Grass can grow naturally between the rows or plant clover, hairy vetch, ryegrass, etc. with extremely low stem lignification and low water consumption. When the grass is 40cm high, it is mowed and covered on the tree tray. Taking Jingning County, Pingliang City, Gansu Province as an example, the distance from the root stock of M9T337 exposed above the ground is 10cm.

[0099] 7. Post-planting management of seedlings

[0100] If the trunk diameter is ≥1.2cm and the height of the seedlings is ≥1.5m, there is no need to fix the trunk when transplanting, but large branches with a branch thickness greater than 2 / 3 of the thickness of the main trunk in the same position, or branches with an angle within 30°, should be removed with 2cm short stumps.

[0101] After the seedlings are set, use 5 cm wide plastic tube film to cover the trunk of the seedlings, and compact the root neck of the seedlings with soil to prevent air leakage. Twist the tube film several times along the seedlings to reduce the gaps in the tube film and prevent the tube film from being blown up by strong winds. Tighten the tube film mouth at the top. After the seedlings germinate and the buds are 3 cm long, untie the tube film mouth in time for ventilation. After 7 days of adaptation to the external environment, remove the tube film on a cloudy day. You can also cut the plastic mulch into 10 cm wide and wrap the trunk from bottom to top to moisturize.

[0102] For mountain orchards with an altitude above 1500m and relatively cold climate (such as Jingning County, Pingliang City, Gansu Province), it is recommended to carry out short pruning on the seedlings after they have recovered from transplant shock. The principle is not to prune the central trunk and the main branches with a length of less than 10cm. For the main branches with a length ≤ 50cm, the tip is short-pruned by 10cm. For the main branches with a length ≥ 50cm, they are short-pruned to 50cm. For the branches with an angle within 30° and competing with the central trunk, leave 10cm at the base and remove them. For the main branches below 60cm from the ground of the central trunk, directly remove them. For the mechanically damaged, broken, and dried branches, short-prune them to the healthy part. When the buds at the top of the branches begin to swell, methods such as bud carving or applying shoot-promoting agent can be used to increase the germination rate. For the extended branch of the central trunk, select a bud with a suitable direction every 15cm from the base upwards, and cut through the cortex 0.5cm above the bud, or apply shoot-promoting agent on the bud. For the lateral branches, start from 10cm away from the main trunk and carry out bud carving or apply shoot-promoting agent on the lateral and back buds at 3 / 4 of the total length of the branch.

[0103] Conventional planting method:

[0104] 1. Seedling quality:

[0105] The rootstock is M9T337 self-rootstock. The seedling height is above 1.2m. The rootstock length of the dwarf self-rootstock is 20cm. The trunk diameter at 10cm above the grafting joint of the seedling variety is greater than 1cm. There are more than 5 branches and more than 6 plump buds in the shaping zone with a length of 40 - 50cm on the main trunk of the seedling, distributed staggeredly. The main root is thick, there are many lateral roots, evenly distributed, and the capillary roots are relatively dense. There are more than 3 lateral roots with a diameter greater than 0.3cm and a length exceeding 20cm; there are more than 6 lateral roots with a diameter greater than 0.2cm and a length exceeding 20cm, and there are an appropriate amount of small and dense fibrous roots.

[0106] 2. Seedling transportation and storage:

[0107] During the transportation and storage of seedlings, protect the roots and branches of the seedlings well to prevent problems such as damage, dehydration, and frost damage of the seedlings. Before planting, the roots can be appropriately pruned, mainly pruning some cracked roots, or some broken roots and overlong roots, but the pruning should not be too heavy. If the roots in the underground part are small, the branches with too thick branches can be removed by leaving a short stub of 2 - 4cm. After the seedlings are out of the nursery, if they cannot be transported immediately or cannot be planted immediately after transportation, they should be immediately stored in a cold storage. The temperature in the cold storage is 1℃, and the humidity is above 95%. For the storage of seedlings by false planting, the time does not exceed 10 days. The roots of the seedlings can be moisturized with sand, sawdust, straw, and straw curtains. It is necessary to regularly check the humidity of the sand and the seedlings. The sand is replenished with water once every 10 days, and the sunshade net is sprinkled with water once every 2 days.

[0108] 3. Seedling planting time:

[0109] Taking Jingning County, Pingliang City, Gansu Province as an example, the planting is carried out approximately after March 31.

[0110] 4. Soil treatment before planting nursery stock:

[0111] Before the soil freezes in autumn, level the soil before land preparation. Before land preparation, harrow the soil flat. Dig a planting trench with a width and depth of 0.8 m according to the planned planting row. Mix the excavated topsoil and subsoil, irrigate and let it settle to prepare for tree planting in the following year. In the following spring, use white lime to mark points according to the planned plant spacing. For dwarf self-rootstock nursery stock, dig a planting hole with a side length of 50 cm.

[0112] 5. Sterilization and root-promoting treatment of nursery stock:

[0113] Before planting nursery stock, carefully check whether there are dry rot disease spots above and below the graft union, and use pruning shears to cut the lateral roots to check for lesions such as brown discoloration. The trimmed roots of the nursery stock should be fully soaked in water for 24 h to maintain the activity of the nursery stock, and plant immediately after treatment.

[0114] 6. Planting method of nursery stock:

[0115] When establishing an orchard with dwarf self-rootstock nursery stock, the plant spacing is 1.2 m × 3.5 m, and 158 plants are planted per mu. When planting, place the nursery stock in the planting hole, make the root system evenly distributed, keep the graft union facing in the same direction, straighten the nursery stock, align the rows, and the nursery stock should not exceed 15 cm from the lattice fiber rod. Backfill fine soil around the roots until all the roots are covered, then lift the nursery stock to stretch the roots and trample firmly. Irrigate 30 kg of water into the planting hole. When the water has infiltrated by 1 / 2, immediately fill the hole with fine soil, and at the same time correct the planting position. When the root collar is buried, gently step on it and sprinkle a layer of fine soil. The settling water must be poured thoroughly. For orchards with drip irrigation conditions, 10 cubic meters of water can be watered per mu before planting. After planting the nursery stock, water 10 cubic meters per mu, and water 10 cubic meters per mu after 10 days. After planting, fix the nursery stock on the first and second steel wires with buckles to prevent the nursery stock from lodging caused by watering and wind. Level the tree row into a trough shape, and cover the tree basin with black film or black ground cloth to collect rain and conserve moisture, increase soil temperature, suppress weeds, save nutrients, promote root recovery and rapid growth, and shorten the seedling-slowing period. The coverage width is 1 m, in the shape of a funnel with a low center and high perimeter, fixed with ground nails, and the two sides are compacted with soil, with a drop of about 5 cm. Natural grass can grow in the inter-row or plant clover, hairy vetch, ryegrass, etc. with extremely low lignification degree of the stem and low water consumption. After the grass grows to 40 cm, cut it and cover it on the tree basin. Taking Jingning County, Pingliang City, Gansu Province as an example, the distance of the M9T337 self-rootstock exposed above the ground is 15 cm.

[0116] 7. Management after planting nursery stock:

[0117] For nursery stock with a trunk diameter ≤ 1 cm, after planting, promptly determine the trunk height at a plump bud. The general trunk height is 80 cm, and remove the buds within 10 cm below the pruning cut to prevent the emergence of competing branches that may affect the growth of the top shoot. Immediately protect the pruning cut with pruning sealant or Fluke agent, or use agricultural film to make a plastic bag to cover the nursery stock to prevent water loss and frost damage. If the growth of the nursery stock is not strong in the second year and subsequent years, trunk height determination must be continuously carried out.

[0118] After determining the trunk height of the nursery stock, use a 5-cm-wide plastic tube film to cover the trunk of the nursery stock, and compact the soil at the root neck of the nursery stock to prevent air leakage. Twist the tube film around the nursery stock a few times to reduce the space inside the tube film and prevent the tube film from being blown apart by strong winds. Tie the upper end of the tube film tightly. When the buds on the nursery stock grow to 3 cm after germination, promptly untie the mouth of the tube film for ventilation. After adapting to the external environment for 7 days, remove the tube film on a cloudy day. Alternatively, cut the plastic mulch film into 10 cm wide and wrap the trunk from bottom to top to play a role in moisturizing.

[0119] For mountain orchards with an altitude higher than 1500 m and relatively cold and cool climates (such as Jingtai County, Pingliang City, Gansu Province), it is recommended to carry out short pruning on the nursery stock after the seedlings have recovered. The principle is not to prune the central trunk and the main branches with a length of no more than 10 cm. Shorten the tip of the main branches with a length ≤ 50 cm by 10 cm, and shorten the main branches with a length ≥ 50 cm to 50 cm. For branches with an angle within 30° and competing with the central trunk, leave 10 cm at the base and remove them. Directly remove the main branches below 60 cm from the ground of the central trunk. Shorten the mechanically damaged, broken, and dried branches to the healthy part. When the buds at the top of the branches begin to swell, the method of bud carving can be adopted to improve the germination rate. For the extended branch of the central trunk, select a bud with a suitable direction every 15 - 20 cm from the base upwards, and break the cortex 0.5 cm above the bud; for the lateral branches, start from 10 cm away from the main trunk and carry out bud carving on the lateral and back buds at 3 / 4 of the total length of the branch.

[0120] Modern Dwarf Rootstock Apple Demonstration Garden, Jutou Village, Chengchuan Town, Jingning County, Pingliang City

[0121] In the spring of 2024, plant dwarf rootstock apple nursery stock according to this invention patent. The survival rate of the nursery stock is 96.5%, which is 13.5 percentage points higher than that of the conventional planting method.

[0122] Table 1 Investigation of the survival situation of dwarf rootstock nursery stock in July 2024 (growth situation of fine roots ≤ 2 mm in the 0 - 40 cm vertical soil layer)

[0123]

[0124] As can be seen from Table 1, the investigation of the distribution of fine roots with an absorption function for a diameter ≤ 2 mm shows that: adopting the planting method of the invention patent can significantly increase the number, root length, and root surface area of fine roots in the soil layers of 0 - 20 cm and 20 - 40 cm, which are increased by 109.41%, 85.38%, 115.23%, 107.23%, 61.25%, and 85.35% respectively compared with the conventional planting method. And it promotes the increase of the root surface area of fine roots in the 20 - 40 cm soil layer. Compared with the 0 - 20 cm soil layer, the planting method of the invention patent increases it by 43.97%, and the growth rate is higher than that of the conventional planting method by 25.25%, which is beneficial for the roots to penetrate deeply and enhance the absorption capacity of water and fertilizer in the deep soil. Only when the root system grows well and can normally absorb water and nutrients in the soil can the survival rate of apple dwarfing rootstock seedlings be improved.

[0125] On April 30, 2024 (cloudy day), the daily variation of the soil temperature in the 0 - 60 cm soil layer was monitored, and the results are shown in Figure 2-4 , adopting the planting method of the invention patent can effectively increase the soil temperature in the 0 - 20 cm, 20 - 40 cm, and 40 - 60 cm soil layers. The soil temperature in the 0 - 20 cm soil layer is increased by 1.8 °C and 9.6 °C compared with the conventional planting method at the lowest and highest daily temperatures. The soil temperature in the 40 - 60 cm soil layer is increased by 2.1 °C and 2.5 °C compared with the conventional planting method at the lowest and highest daily temperatures. Effectively increasing the soil temperature in the root distribution layer in spring is beneficial for the roots to absorb soil water and nutrients, beneficial for the decomposition of fertilizers by soil microorganisms, convenient for the full absorption and utilization of apple roots, and achieves the purpose of improving the survival rate of apple dwarfing rootstock seedlings.

[0126] Table 2 Results of different components and contents in the root - soaking water

[0127]

[0128] High - concentration salicylic acid and chitosan will inhibit root growth, and at low concentrations, the effect of promoting root growth and development is weak.

[0129] Example 2

[0130] The planting method of the invention patent in this example is the same as that in Example 1, and the conventional planting method is the same as that in Example 1.

[0131] Modern Dwarfing Apple Demonstration Garden, Yuwan Village, Yuwan Township, Jingning County, Pingliang City

[0132] In the spring of 2024, dwarfing apple seedlings were planted according to the invention patent of this example, and the survival rate of the seedlings was 95.8%, which was 11.5 percentage points higher than that of the conventional planting method.

[0133] Table 2 Investigation of the survival situation of dwarfing rootstock seedlings in July 2024 (Growth situation of fine roots with a diameter ≤ 2 mm in the 0 - 40 cm vertical soil layer)

[0134]

[0135] Investigation on the distribution of fine roots with an absorption function for diameters ≤ 2 mm shows that: By using the planting method of the invention patent, the number, root length, and root surface area of fine roots in the soil layers of 0 - 20 cm and 20 - 40 cm can be significantly increased, which are 161.49%, 80.62%, 188.49%, 84.73%, 176.87%, and 46.78% higher than those of the conventional planting method respectively. Only when the root system grows well and can normally absorb water and nutrients in the soil can the survival rate of apple dwarf rootstock seedlings be improved.

[0136] On May 5, 2024 (sunny day), the daily variation of the soil temperature in the soil layer of 0 - 60 cm was monitored. The results are shown in Figure 6-8 , By using the planting method of the invention patent, the soil temperature in the soil layers of 0 - 20 cm, 20 - 40 cm, and 40 - 60 cm can be effectively increased. The soil temperature in the 0 - 20 cm soil layer is 2.5℃ and 8.5℃ higher than that of the conventional planting method at the lowest and highest daily temperatures respectively. The soil temperature in the 40 - 60 cm soil layer is 1.5℃ and 1.6℃ higher than that of the conventional planting method at the lowest and highest daily temperatures respectively. Effectively increasing the soil temperature in the root distribution layer in spring is beneficial to the roots to absorb soil water and nutrients, beneficial to the decomposition of fertilizers by soil microorganisms, convenient for the full absorption and utilization of apple roots, and achieves the purpose of improving the survival rate of apple dwarf rootstock seedlings.

[0137] Example 3

[0138] The planting method of this invention patent is the same as that in Example 1, and the conventional planting method is the same as that in Example 1.

[0139] Dazhuang Village, Zhiping Town, Jingning County, Pingliang City, Modern Dwarf Rootstock Apple Demonstration Garden

[0140] In the spring of 2024, dwarf rootstock apple seedlings were planted according to this invention patent, and the survival rate of the seedlings was 96.5%, which was 14.5 percentage points higher than that of the conventional planting method.

[0141] Table 3 Investigation on the survival of dwarf rootstock seedlings in July 2024 (Growth of fine roots ≤ 2 mm in the 0 - 40 cm vertical soil layer)

[0142]

[0143] Investigation on the distribution of fine roots with an absorption function for diameters ≤ 2 mm shows that: Using the planting method of the invention patent can significantly increase the number, root length, and root surface area of fine roots in the soil layers of 0 - 20 cm and 20 - 40 cm. Compared with the conventional planting method, it has increased by 157.49%, 169.23%, 140.98%, 114.67%, 91.87%, and 94.89% respectively. And it promotes the increase of the root surface area of fine roots in the 20 - 40 cm soil layer. Compared with the 0 - 20 cm soil layer, the planting method of the invention patent has increased by 22.59%, and the growth rate is higher than that of the conventional planting method, which is 20.76%, facilitating the deep rooting of the roots and increasing the absorption capacity of water and fertilizer in the deep soil. The roots grow well and can normally absorb the water and nutrients in the soil, so as to improve the survival rate of apple dwarf rootstock seedlings.

[0144] Monitoring the daily variation of soil water content in the 0 - 60 cm soil layer on May 2, 2024, the results are shown in Figure 10-12 , Using the planting method of the invention patent can effectively increase the soil water content in the soil layers of 0 - 20 cm, 20 - 40 cm, and 40 - 60 cm. The soil water content in the 0 - 20 cm soil layer has increased by 41.19 - 53.68% compared with the conventional planting method. The soil water content in the 40 - 60 cm soil layer has increased by 17.02 - 18.05% compared with the conventional planting method. Effectively increasing the soil water content in the root distribution layer in spring is conducive to the decomposition of fertilizers by soil microorganisms, facilitating the full absorption and utilization of apple roots, and achieving the purpose of improving the survival rate of apple dwarf rootstock seedlings.

[0145] Although the above embodiments have made a detailed description of the present invention, they are only a part of the embodiments of the present invention, not all embodiments. People can also obtain other embodiments based on this embodiment without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A cultivation method for improving the survival rate of dwarf rootstock apple seedlings in the cold and arid regions of Northwest China, characterized by It includes the following steps: 1) Prepare the soil before the soil freezes in autumn of the current year, dig planting trenches, lay crop straw at the bottom of the planting trenches, spray urea solution, mix the excavated soil with decomposed farmyard manure and then backfill the planting trenches, and irrigate and compact; 2) In spring of the second year, when the soil temperature of the soil layer of 20 - 40 cm is higher than 8 - 10 °C, dig planting holes on the planting trenches in the step 1), and transplant dwarfing apple seedlings in the planting holes; Before transplanting, the dwarfing apple seedlings are soaked in root and dipped in root in sequence; The water used for soaking in root contains 400 mg / L salicylic acid, 300 mg / L chitosan, 1.25 g / L white sugar, 0.45 g / L soybean flour and 1.5 g / L vitamin B12; The components of dipping in root are carbendazim, superphosphate, fine soil and water, and the mass ratio of carbendazim, superphosphate, fine soil and water is 2:10.2:15:100; The grafting interface of the dwarfing apple seedlings is exposed 3 - 10 cm above the ground; The standards of the dwarfing apple seedlings are as follows: the seedling height is above 1.2 m, the stem diameter at 10 cm above the grafting interface is greater than 1.2 cm, there are more than 8 branches in the shaping zone of 40 - 50 cm in length, more than 10 plump buds, distributed staggeredly, the main root is thick, there are many lateral roots, evenly distributed, the capillary roots are dense, there are more than 5 lateral roots with a diameter greater than 0.3 cm and a length exceeding 20 cm, there are more than 10 lateral roots with a diameter greater than 0.2 cm and a length exceeding 20 cm, and there are many small and dense fibrous roots; The dwarfing apple seedlings include dwarfing interstock apple seedlings or dwarfing self-rooted apple seedlings. The length of the dwarfing stock of the dwarfing interstock apple seedlings is 25 cm, and the length of the rootstock of the dwarfing self-rooted apple seedlings is 20 cm; The varieties of the dwarfing apple seedlings are Fuji, Yuhua, New Red Star, Honeycrisp, Short Branch Fuji, Gala, Golden Delicious, Granny Smith, Jonathan or Pink Lady; when the altitude is higher than 1500 m, short cutting and pruning are carried out on the dwarfing apple seedlings after slow seedling.

2. The cultivation method according to claim 1, characterized in that, The width and depth of the planting trenches in the step 1) are both 0.8 - 1 m; The laying thickness of the crop straw is 10 - 20 cm. The crop straw includes wheat straw, and the length of the crop straw is preferably 10 - 20 cm; The mass percentage content of the urea solution is 0.5%; The usage amount of the urea solution is 20 L / mu; The types of the decomposed farmyard manure include decomposed sheep manure, and the application rate is 10 - 20 m 3 / mu.

3. The cultivation method according to claim 1, characterized in that, When the dwarfing apple seedlings in the step 2) are dwarfing interstock apple seedlings, the planting holes are 60 cm square; When the dwarfing apple seedlings are dwarfing self-rooted apple seedlings, the planting holes are 40 cm square.

4. The cultivation method according to claim 1, characterized in that, When the dwarfing apple seedlings in the step 2) are dwarfing interstock apple seedlings, the row spacing is 1.5 - 2 m × 4 m, and the transplanting density is 84 - 110 plants / mu; When the dwarfing apple seedlings are dwarfing self-rooted apple seedlings, the row spacing is 1 - 1.2 m × 3.5 m, and the transplanting density is 158 - 190 plants / mu.

5. The cultivation method according to claim 1, characterized in that, The soaking time of the root in the step 2) is 24 - 48 h.

6. The cultivation method according to claim 1, characterized in that, When the rootstock varieties of the dwarfing apple seedlings in the step 2) are Fuji or Yuhua varieties, the distance from the grafting interface to the ground is 8 - 10 cm; When the rootstock variety is Starkrimson, Honeycrisp, Spur Fuji or Gala, the distance from the graft union to the ground is 3 - 5 cm; When the rootstock variety is Golden Delicious, Granny Smith, Jonathan or Pink Lady, the distance from the graft union to the ground is 5 - 8 cm.

7. The cultivation method according to claim 1, characterized in that, When the dwarf rootstock apple seedlings in step 2) cannot be transplanted immediately, they are stored at a temperature of 0.5 - 1.5 °C, a humidity above 95%, and the storage time does not exceed 10 days.

8. The cultivation method according to claim 1, characterized in that, The standards for the short cut pruning in step 2) are as follows: the central trunk and the main branches with a length of no more than 10 cm are not pruned; the tips of the main branches with a length of 10 - 50 cm are short cut by 5 - 10 cm; the main branches with a length exceeding 50 cm are short cut to 50 cm; the branches with an angle within 30° and competing with the central trunk are removed by leaving 10 cm at the base; the main branches below 60 cm from the ground of the central trunk are directly removed; the mechanically damaged, broken and dried branches are short cut to the healthy parts.

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