Organic fertilizer application method for different young trees of swiss-grown apple in arid regions

Abstract

The application discloses a method for applying organic fertilizer to young trees of different drought areas of Ruisnow apples, and relates to the technical field of agricultural planting. The method comprises the following steps: determining influence factors of the application conditions of the organic fertilizer of the young trees of the Ruisnow apples; determining the relative importance of each influence factor by using a combination weight method; analyzing comprehensive evaluation results of the young trees of the apples under different water-fertilizer coupling treatments to obtain optimal fertilization and irrigation water amounts; applying appropriate organic fertilizer to the planting plots of the young trees of the apples and performing irrigation; and calculating the annual supplementary organic fertilizer amount required by the application through monitoring the growth conditions of the young trees. The method is not dependent on specific regional experience, has strong replicability and promotion value, and can be quickly applied to various unfamiliar environments such as the northwest arid area and the seasonal arid area in North China, thereby providing a standardized and operable technical scheme for the high-quality and efficient cultivation of the young trees of the Ruisnow apples in the arid areas.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, and in particular to a method for applying organic fertilizer to young Ruixue apple trees in different arid regions. Background Technology

[0002] The Loess Plateau region, one of my country's two major apple-producing areas, encompasses the main apple-producing regions of Shaanxi, Gansu, Shanxi, and Henan provinces. Shaanxi Province, with its unique geographical advantages and favorable climate (arid and semi-arid), is one of the best apple-producing regions in China and even the world. The 'Ruixue' apple tree, a high-quality, late-maturing, yellow-green variety developed domestically in recent years, is characterized by its ease of cultivation (short-branch type, easy flowering, early fruiting, high yield, and strong resistance), beautiful appearance (large fruit, small lenticels, no rust), excellent quality (fine, crisp, and fragrant flesh), and good storage life (late-maturing, extremely resistant to storage). It is widely loved, and its tall, well-colored fruit with a rich aroma and good storage life, along with high resistance to powdery mildew and brown spot, gives it a promising market prospect.

[0003] However, apple cultivation in the Loess Plateau region also faces unavoidable technical challenges. On the one hand, due to the lack of adequate irrigation, rainfed agriculture becomes the primary source of water for apple trees. Uneven rainfall distribution throughout the year often results in seasonal droughts—early spring and summer followed by autumn floods—which restrict tree growth and development. On the other hand, although these regions currently have a large number of orchards, the overall soil is poor, with poor water and fertilizer retention capacity and low organic matter content, which also hinders the healthy and green development of the apple industry in the region. Furthermore, most areas in this region are located in my country's arid and semi-arid climate zones, with weak soil fertility, further restricting the sustainable development of this variety in the area.

[0004] Therefore, this invention proposes a method for applying organic fertilizer to young Ruixue apple trees in different arid regions. Summary of the Invention

[0005] This invention provides a method for applying organic fertilizer to young Ruixue apple trees in different arid regions. By adjusting the amount of fertilizer applied to young Ruixue apple trees in different arid regions, this invention solves the technical problem in the prior art where apple trees cannot achieve sustainable development due to soil fertility.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a method for applying organic fertilizer to young Ruixue apple trees in different arid regions, comprising: S1, Determine the influencing factors of organic fertilizer application conditions on young Ruixue apple trees; S2, the relative importance of each influencing factor is determined by the combined weighting method; S3, analyze the comprehensive evaluation results of apple sapling indicators under different water and fertilizer coupling treatments, and obtain the optimal fertilization and irrigation amounts; S4. Apply an appropriate amount of organic fertilizer to the planting area of ​​the apple saplings and irrigate. S5 calculates the required annual amount of supplemental organic fertilizer by monitoring the growth of young trees.

[0007] The beneficial effects of the technical solution provided by this invention include at least the following: This invention proposes a zoned management strategy of "fertilization based on water availability," which measures multiple parameters including soil background organic matter, water zone targets, topsoil weight, and organic fertilizer content. This allows for targeted adjustments to the amount of organic fertilizer applied to young Ruixue apple trees in different arid regions, ensuring that the trees grow in optimal condition.

[0008] This invention improves the soil's water retention capacity by constructing an evaluation index system for moisture retention effect and calculating the moisture retention replacement rate. Based on the combined weights, a weighted analysis is performed to accurately select the treatment combination with the best overall performance from different water-fertilizer coupling treatments, providing clear fertilization targets for different water conditions.

[0009] This invention constructs a complete closed-loop dynamic management system of "diagnosis-calculation-application-monitoring-adjustment", which not only solves the problem that static fertilization cannot cope with the annual mineralization of soil organic matter, but also ensures that soil fertility is maintained at the optimal level in the long term through annual monitoring and replenishment calculation.

[0010] In summary, all parameters of the method of this invention can be obtained through conventional testing, do not depend on specific regional experience, have strong replicability and promotion value, and can be quickly applied to various unfamiliar environments such as the arid Northwest region and the seasonally arid North China region. It provides a standardized and operable technical solution for the high-quality and efficient cultivation of Ruixue apple saplings in arid regions. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a flowchart of the organic fertilizer application method for young Ruixue apple trees in different arid regions, provided by an embodiment of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Example

[0014] A method for applying organic fertilizer to young Ruixue apple trees in different arid regions.

[0015] Please refer to Figure 1 This is a flowchart of the organic fertilizer application method for young Ruixue apple trees in different arid regions, provided by an embodiment of the present invention.

[0016] S1, Determine the influencing factors of organic fertilizer application conditions on young Ruixue apple trees; Factors influencing the performance indicators of young apple trees include growth physiological indicators, water and fertilizer use efficiency indicators, dry matter weight, and yield indicators. It should be noted that the dry matter quality index is determined as follows: the rootstock of the apple tree is separated from the underground part, cleaned, and then placed in a drying oven at 105℃ for 0.5 hours to fix the green color. After drying at 75℃ until the mass remains unchanged, it is placed in a desiccator for cooling. After cooling, the mass is weighed using an electronic balance, which is the dry matter quality index. The yield index is determined with reference to the average yield of Ruixue apple trees.

[0017] The growth and physiological indicators of apple saplings include plant growth and basal stem growth, leaf area, net photosynthetic rate and transpiration rate, and chlorophyll SPAD value. It should be noted that the plant growth was measured using a steel tape measure, starting from the marked point at the base of the rootstock and measuring the height to the highest point of the tree top; the basal stem growth was measured using a steel ruler and vernier calipers, starting from the marked point at the base of the rootstock, using the cross-sectional method to measure the diameter and taking the average value to reduce error.

[0018] The leaf area of ​​a single leaf of the plant was measured using a handheld leaf area meter. During the measurement process, 10 leaves from each of the upper, middle and lower directions were randomly selected, and the average value was calculated as the result. Plant leaf area = single leaf area × number of leaves.

[0019] On a sunny morning, the net photosynthetic rate (Pn) and transpiration rate (Tr) of intact leaves in the middle and upper parts of apple saplings were measured using a photosynthesis meter. During the measurement, five leaves were selected from each apple tree, and three stable data points were collected for each measurement. The final data for each treatment was the average of the five leaves to reduce error.

[0020] When using a chlorophyll meter to measure SPAD values, 12 leaves from each tree were randomly selected from the top, middle, and bottom directions to test SPAD. The value is taken as the average value, and the measurement location is 2 / 3 of the way down one side of the leaf petiole.

[0021] The indicators of water and fertilizer use efficiency for young apple trees include water use efficiency, water productivity, irrigation water use efficiency, and fertilizer partial productivity.

[0022] It should be noted that the formula for calculating water use efficiency is: In the formula, Expressed as net photosynthetic rate, in μmol·m⁻²·s⁻¹; The transpiration rate is expressed in mmol·m⁻²·s⁻¹.

[0023] The formula for calculating water productivity is: In the formula, Expressed as dry matter weight, in g / plant; Water consumption is expressed in L per plant.

[0024] The formula for calculating irrigation water use efficiency is: In the formula, This is expressed as the yield of apple trees, in grams per tree.

[0025] The formula for calculating the partial productivity of fertilizer is: In the formula, The amount of fertilizer applied is expressed in grams per plant.

[0026] S2, the relative importance of each influencing factor is determined by the combined weighting method; S201. Using the analytic hierarchy process, a judgment matrix is ​​constructed based on the importance of each evaluation indicator to the quality, with the lower-level indicators relative to the higher-level indicators, and the subjective weights of each indicator are calculated. It should be noted that the specific process of the Analytic Hierarchy Process (AHP) is as follows: For different evaluation indicators, the indicators are divided into target layer, criterion layer, and indicator layer (where the criterion layer includes growth physiological indicators, water and fertilizer use efficiency indicators, and dry matter and yield indicators; the indicator layer includes plant growth, basal stem growth, leaf area, net photosynthetic rate, transpiration rate, chlorophyll SPAD value, water use efficiency, water productivity, irrigation water use efficiency, fertilizer partial productivity, dry matter, and yield). For each level, a judgment matrix is ​​constructed using the 1-9 scaling method, and the importance of indicators in the same level is compared pairwise. By normalizing the judgment matrix, the subjective weight vector is calculated.

[0027] S202 adopts the CRITIC weighting method, which measures the objective weight of each judgment indicator based on the comparative strength of the evaluation indicators and the conflict between the indicators. It should be noted that the calculation process of objective weights is as follows: construct the original data matrix containing the measured values ​​of each indicator, and use the range normalization method to convert the data into a dimensionless standardized matrix; calculate the standard deviation of each indicator to reflect the comparative strength of the indicators, calculate the correlation coefficient matrix between each indicator and the conflict between each indicator and other indicators; calculate the information content of each indicator based on the standard deviation and conflict, and obtain the objective weights after normalizing the information content.

[0028] S203 combines subjective weights and objective weights, and calculates the combined weights using the multiplier synthesis normalization method.

[0029] It should be noted that the calculation process of the combined weights is as follows: the subjective weights obtained by the analytic hierarchy process and the objective weights obtained by the CRITIC weighting method are multiplied by the corresponding influencing factors, and the product vector is normalized to obtain the combined weight vector (which must satisfy the condition that the sum of all weights is 1).

[0030] S3, analyze the comprehensive evaluation results of apple sapling indicators under different water and fertilizer coupling treatments, and obtain the optimal fertilization and irrigation amounts; S301, construct an evaluation system for soil moisture retention effect indicators to verify the effect of increasing the application of organic fertilizer on improving soil moisture retention capacity; The evaluation system for young apple trees includes soil physical indicators, water consumption indicators, and economic indicators. It should be noted that soil physical indicators include soil bulk density, field water holding capacity, content of water-stable aggregates larger than 0.25 mm, and soil evaporation; water consumption indicators include relative leaf water content and water use efficiency of fruit trees; and economic indicators include organic fertilizer cost, irrigation cost, and output benefits.

[0031] S302 introduces a cost function and constructs an economic evaluation model that includes fertilization costs and irrigation costs; The cost function for apple saplings is derived by adding the cost of organic fertilizer to the cost of irrigation. It should be noted that the calculation process of the economic evaluation model is as follows: define the cost function and the benefit function (determined by the price of the fruit, obtained from the yield and price of a single Ruixue variety fruit tree); calculate the input-output ratio and net income based on the cost function and the benefit function.

[0032] S303, a comprehensive evaluation system including influencing factors and moisture retention effect was constructed and TOPSIS analysis was performed to obtain the relative closeness ranking results of each water-fertilizer coupling treatment combination; S304 determines the optimal fertilizer application rate for different drought types based on water conditions and regional divisions.

[0033] It should be noted that the specific steps are as follows: the treatment combinations are divided into three groups according to water conditions: moderate drought group (relative soil moisture content 50%-60%), mild drought group (relative soil moisture content 60%-70%), and normal irrigation group (relative soil moisture content 70%-80%); the net benefit and input-output ratio of each fertilization treatment in each group are calculated; the fertilization treatment with the highest net benefit or the largest input-output ratio in each group is selected; the correspondence between water conditions and optimal fertilization amount is established, and a regional recommendation scheme is generated.

[0034] The recommended zoning schemes are as follows: For moderately arid areas where the relative soil moisture content is consistently between 50% and 60%, a fertilizer application rate corresponding to 2% soil organic matter content is recommended; for mildly arid areas where the relative soil moisture content is between 60% and 70%, a fertilizer application rate corresponding to 2% or 3% soil organic matter content is recommended, with the specific value determined based on the moisture retention effect and cost analysis results; for normally irrigated areas where the relative soil moisture content is between 70% and 80%, a fertilizer application rate corresponding to 3% soil organic matter content is recommended.

[0035] Methods for verifying indicators of young apple trees include: The differences in soil bulk density, field water holding capacity, and water-stable aggregate content under different organic matter content treatments were compared to verify that the soil water retention capacity is significantly enhanced with the increase of organic matter content. Response curves of irrigation amount and growth amount under different organic matter treatments were constructed to analyze whether the growth amount of high organic matter treatment under medium and low irrigation conditions reached the growth amount of low organic matter treatment under normal irrigation conditions. Calculate the moisture retention replacement rate to quantify the degree to which organic fertilizer compensates for water deficit.

[0036] It should be noted that the formula for calculating the moisture retention replacement rate is: In the formula, This indicates the growth rate under high organic matter and low irrigation conditions. This indicates growth under low organic matter and low irrigation treatment. This indicates the growth rate under normal irrigation treatment with low organic matter content.

[0037] The process of TOPSIS analysis of apple sapling indicators includes: constructing an extended decision matrix, normalizing the decision matrix, constructing a weighted matrix, and calculating the relative closeness of each combination; The extended decision matrix for apple sapling indicators is obtained by combining input-output ratio, net income, growth indicators, and moisture retention indicators. It should be noted that the process of constructing the extended decision matrix is ​​as follows: In the formula, This represents the measured value of the i-th treatment on the j-th index; This represents the number of water-fertilizer coupling treatment combinations; This indicates the number of evaluation indicators.

[0038] The normalized decision matrix for apple sapling indicators is obtained by transforming the indicators in the extended decision matrix to be consistent in direction and then normalizing the matrix using the vector normalization method. It should be noted that, It should be noted that, This represents the normalized value of the i-th processing on the j-th metric; This represents the original measured value of the i-th treatment after directional alignment on the j-th index.

[0039] The weighted matrix of apple sapling indicators is obtained by multiplying the normalized decision matrix by the combined weight vector; It should be noted that the construction process of the weighted matrix is ​​as follows: In the formula, This represents the combined weight.

[0040] The relative closeness of the apple sapling index is obtained by calculating the Euclidean distance between each combination and the positive and negative ideal solutions.

[0041] It should be noted that the positive ideal solution takes the maximum value of each column in the weighted matrix, and the negative ideal solution takes the minimum value of each column in the weighted matrix; after the relative closeness calculation is completed, the processing combinations are sorted from largest to smallest. S4. Apply an appropriate amount of organic fertilizer to the planting area of ​​the apple saplings and irrigate. S401. Determine the fertilization location based on the planting site of the apple saplings, and dig fertilization trenches 30-40cm deep and 20-30cm wide. It should be noted that the fertilization period is from mid-September to mid-October, which coincides with the third peak growth period of the fruit tree's root system, which is conducive to the absorption of organic fertilizer nutrients and the healing of root damage.

[0042] The fertilization location is determined by forming a ring-shaped fertilization area around the planting point with the trunk as the center. A ring-shaped trench is dug at the outer edge of the canopy projection, with a depth of 30-40cm and a width of 20-30cm. The diameter of the ring-shaped trench is determined according to the size of the canopy. For young trees, a trench depth of 35cm and a width of 25cm are optimal.

[0043] S402: Mix an appropriate amount of organic fertilizer thoroughly with the soil excavated during the fertilization trench and backfill it into the fertilization trench, then cover the surface with soil. The soil covering should be 2-5 cm thick, so that the surface of the fertilization trench is slightly higher than or level with the surrounding area, to prevent water accumulation.

[0044] It should be noted that the specific operation for thoroughly mixing soil and organic fertilizer is as follows: First, backfill some of the excavated soil to the bottom of the fertilizer trench, so that it comes into initial contact with the organic fertilizer. Then, use a shovel or mechanical mixing device to repeatedly turn the soil and organic fertilizer in the trench until there are no obvious fertilizer clumps visible to the naked eye, and the soil and fertilizer are evenly mixed. During the mixing process, ensure that the organic fertilizer is buried in the main root distribution layer at a depth of 20-40cm.

[0045] After the organic fertilizer is applied, the decision on whether to carry out irrigation is based on the preset moisture content threshold and the measured relative soil moisture content. The relative soil moisture content is measured by the ratio between the actual soil moisture content and the field capacity. It should be noted that the soil moisture content was determined using the oven-drying method, and the field capacity was measured simultaneously. The relative soil moisture content was calculated using the following formula: Relative soil moisture content = (soil moisture content / field capacity) × 100%.

[0046] The preset moisture content threshold is 60%.

[0047] It should be noted that if the relative soil content is in the range of 50%-59%, the irrigation water volume is 5-10L; if the relative soil content is in the range of 40%-49%, the irrigation water volume is 10-20L; and if the relative soil content is in the range of 30%-39%, the irrigation water volume is 20-35L.

[0048] S5 calculates the required annual amount of supplemental organic fertilizer by monitoring the growth of young trees; S501, based on the comparison of tree growth status indicators, obtain the evaluation results of the growth status of saplings; The evaluation indicators include new shoot length, leaf color, leaf thickness, and total nitrogen content in the leaves; S502 calculates the basic amount of organic fertilizer to be replenished based on the consumption of soil organic matter mineralization, and determines the weighting coefficient based on the evaluation results of the growth status of young trees, and comprehensively calculates the annual organic fertilizer replenishment quality.

[0049] It should be noted that the formula for calculating the basic amount of organic fertilizer to be added is as follows: In the formula, This indicates the basic amount of organic fertilizer to be added; This represents the annual mineralization rate, ranging from 2% to 4%, and is determined based on local climate conditions and soil texture.

[0050] The weighting coefficient is determined based on the growth status of the sapling. When the growth status is excellent, the value is 0.8 to 1.0; when the growth status is normal, the value is 1.0 to 1.2; and when the growth status is weak, the value is 1.2 to 1.5.

[0051] The formula for calculating the annual required amount of organic fertilizer is as follows: In the formula, This indicates the quality of organic fertilizer that needs to be replenished; Indicates the weighting coefficient; This indicates the amount of deviation correction for organic fertilizer; This represents the correction factor, with a value ranging from 0.2 to 0.5.

[0052] The tree's growth status was determined using the following methods: The shoot length was measured and compared with the standard value of the same variety and age to obtain the shoot growth index; the relative chlorophyll content of the leaves was measured using a chlorophyll meter to obtain the leaf color index; the leaf thickness was measured and compared with the standard value to obtain the leaf thickness index; leaf samples were collected, the total nitrogen content was measured and compared with the suitable range to obtain the leaf nitrogen nutrition index. It should be noted that the optimal measurement time is from late July to early August each year. The specific measurement steps are as follows: Randomly select 20-30 new shoots of the current year from the middle of the outer periphery of the tree canopy, measure their length, and calculate the average value as the actual value of the new shoot length. Select 50-100 functional leaves (the 5th to 8th leaves of the new shoots) from the middle of the outer periphery of the tree canopy, measure their SPAD values, and calculate the average value as the actual value of the leaf color. Select 50-100 functional leaves from the middle of the outer periphery of the tree canopy, measure their thickness using a leaf thickness measuring instrument, and calculate the average value as the actual value of the leaf thickness. Collect 50-100 functional leaves from the middle of the outer periphery of the tree canopy, wash, kill the green, dry, and crush them, and then determine the total nitrogen content (dry basis) of the leaves using the Kjeldahl method or the Dumas combustion method to obtain the actual value. The evaluation results are obtained by weighting and combining the growth status with the judgment indicators, and the evaluation results are used as weight coefficients.

[0053] It should be noted that the calculation formula for the evaluation results is as follows: In the formula, Indicates the evaluation result; This represents the index of each individual indicator; The values ​​represent the adjustment coefficients for each indicator, where: the new shoot length index is 0.3, the leaf color index is 0.3, the leaf thickness index is 0.1, and the leaf nitrogen nutrition index is 0.4.

[0054] A comprehensive score of ≥ 0.9 is considered excellent; a comprehensive score between 0.7 and 0.9 is considered normal; and a comprehensive score < 0.7 is considered weak.

[0055] Furthermore, it should be noted that the present invention can be provided as a method, apparatus, or computer program product. Therefore, embodiments of the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code.

[0056] The embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0057] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing terminal equipment to cause a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0058] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0059] Finally, it should be noted that the above description represents a preferred embodiment of the present invention. It should be pointed out that although preferred embodiments have been described, those skilled in the art, once they understand the basic inventive concept of the present invention, can make various improvements and modifications without departing from the principles described herein. These improvements and modifications should also be considered within the scope of protection of the present invention. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Claims

1. A method for applying organic fertilizer to young Ruixue apple trees in different arid regions, characterized in that, include: S1, Determine the influencing factors of organic fertilizer application conditions on young Ruixue apple trees; S2, the relative importance of each influencing factor is determined by the combined weighting method; S3, analyze the comprehensive evaluation results of apple sapling indicators under different water and fertilizer coupling treatments, and obtain the optimal fertilization and irrigation amounts; S4. Apply an appropriate amount of organic fertilizer to the planting area of ​​the apple saplings and irrigate. S5 calculates the required annual amount of supplemental organic fertilizer by monitoring the growth of young trees.

2. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 1, characterized in that, S1 measures the original organic matter content in the soil of the planting site of Ruixue apple saplings, wherein: The influencing factors include growth physiological indicators, water and fertilizer use efficiency indicators, dry matter and yield indicators; The growth physiological indicators include plant growth and basal stem growth, leaf area, net photosynthetic rate and transpiration rate, and chlorophyll SPAD value. The water and fertilizer use efficiency indicators include water use efficiency, water productivity, irrigation water use efficiency, and fertilizer partial productivity.

3. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 1, characterized in that, S2 uses a combined weighting method to determine the relative importance of each influencing factor, wherein: S201. Using the analytic hierarchy process, a judgment matrix is ​​constructed based on the importance of each evaluation indicator to the quality, with the lower-level indicators relative to the higher-level indicators, and the subjective weights of each indicator are calculated. S202 adopts the CRITIC weighting method, which measures the objective weight of each judgment indicator based on the comparative strength of the evaluation indicators and the conflict between the indicators. S203 combines subjective weights and objective weights, and calculates the combined weights using the multiplier synthesis normalization method.

4. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 1, characterized in that, The S3 analysis yielded a comprehensive evaluation of apple sapling indicators under different water-fertilizer coupling treatments, identifying the optimal fertilization and irrigation amounts, among which: S301, construct an evaluation system for soil moisture retention effect indicators to verify the effect of increasing the application of organic fertilizer on improving soil moisture retention capacity; The evaluation system includes soil physical indicators, water consumption indicators, and economic indicators; S302 introduces a cost function and constructs an economic evaluation model that includes fertilization costs and irrigation costs; The cost function is derived by adding the cost of organic fertilizer to the cost of irrigation. S303, a comprehensive evaluation system including influencing factors and moisture retention effect was constructed and TOPSIS analysis was performed to obtain the relative closeness ranking results of each water-fertilizer coupling treatment combination; S304 determines the optimal fertilizer application rate for different drought types based on water conditions and zoning.

5. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 4, characterized in that, The verification of the effect of increased application of organic fertilizer on improving soil moisture retention capacity includes: The verification methods include: The differences in soil bulk density, field water holding capacity, and water-stable aggregate content under different organic matter content treatments were compared to verify that the soil water retention capacity is significantly enhanced with the increase of organic matter content. Response curves of irrigation amount and growth amount under different organic matter treatments were constructed to analyze whether the growth amount of high organic matter treatment under medium and low irrigation conditions reached the growth amount of low organic matter treatment under normal irrigation conditions. Calculate the moisture retention replacement rate to quantify the degree to which organic fertilizer compensates for water deficit.

6. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 4, characterized in that, The construction of a comprehensive evaluation system incorporating influencing factors and moisture retention effects, followed by TOPSIS analysis, yielded a relative proximity ranking of each water-fertilizer coupling treatment combination. The TOPSIS analysis process includes: constructing an extended decision matrix, normalizing the decision matrix, constructing a weighted matrix, and calculating the relative closeness of each combination; The extended decision matrix is ​​obtained by combining the input-output ratio, net income and growth indicators, and moisture retention indicators; The normalized decision matrix is ​​obtained by transforming the indicators in the extended decision matrix to be consistent in direction and then normalizing the matrix using the vector normalization method. The weighting matrix is ​​obtained by multiplying the normalized decision matrix by the combined weight vector; The relative proximity is obtained by calculating the Euclidean distance between each combination and the positive and negative ideal solutions.

7. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 1, characterized in that, In step S4, an appropriate amount of organic fertilizer is applied to the planting area of ​​the apple saplings, and irrigation is carried out, wherein: S401. Determine the fertilization location based on the planting site of the apple saplings, and dig fertilization trenches 30-40cm deep and 20-30cm wide. S402: Mix an appropriate amount of organic fertilizer thoroughly with the soil excavated during the fertilization trench and backfill it into the fertilization trench, then cover the surface with soil. The thickness of the covering soil is 2-5cm, which is used to make the surface of the fertilization trench slightly higher than or level with the surrounding area to prevent water accumulation.

8. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 7, characterized in that, The process involves mixing an appropriate amount of organic fertilizer with the soil and applying it to the trenches surrounding the saplings being evaluated, wherein: After the organic fertilizer is applied, irrigation is determined based on a preset moisture content threshold and the measured relative soil moisture content. The relative soil moisture content is measured by the ratio between the actual soil moisture content and the field capacity. The preset moisture content threshold is 60%.

9. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 1, characterized in that, S5 calculates the required annual amount of supplemental organic fertilizer by monitoring the growth of the saplings, wherein: S501, based on the comparison of tree growth status indicators, obtain the evaluation results of the growth status of saplings; The judgment indicators include new shoot length, leaf color, leaf thickness, and total nitrogen content of leaves; S502 calculates the basic amount of organic fertilizer to be replenished based on the consumption of soil organic matter mineralization, and determines the weighting coefficient based on the evaluation results of the growth status of young trees, and comprehensively calculates the annual organic fertilizer replenishment quality.

10. The method for applying organic fertilizer to young Ruixue apple trees in different arid regions as described in claim 9, characterized in that, The evaluation results of the sapling's growth status are obtained by comparing and judging indicators based on the tree's growth status, wherein: The tree growth status was determined using the following method: The shoot length was measured and compared with the standard value of the same variety and age to obtain the shoot growth index; the relative chlorophyll content of the leaves was measured using a chlorophyll meter to obtain the leaf color index; the leaf thickness was measured and compared with the standard value to obtain the leaf thickness index; leaf samples were collected, the total nitrogen content was measured and compared with the suitable range to obtain the leaf nitrogen nutrition index. The evaluation result is obtained by weighting and combining the growth status with the judgment index, and the evaluation result is used as the weight coefficient.

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