Organic cultivation method of fruit trees based on recycling of forestry waste

Abstract

The application relates to the technical field of organic cultivation of fruit trees, and discloses a fruit tree organic cultivation method based on forestry waste recycling, which comprises the following steps: anaerobic fermentation of nutrient source materials, chelating agents and microbial agents to prepare liquid-phase nutrient solution rich in organic chelated nutrients; low-temperature pyrolysis of carbon skeleton source materials in a limited oxygen atmosphere to obtain active porous carbon skeletons; immersing the carbon skeletons in the nutrient solution under vacuum ultrasonic treatment; anchoring the nutrients on the carriers by increasing the pH value; solid-liquid separation of the mixture, low-temperature drying of the solid-phase materials to obtain a substrate, and finally applying the substrate to the soil for the growth of fruit trees. In the loading and anchoring steps, the chelated nutrients are transported into the active porous carbon skeletons by the synergistic effect of vacuum ultrasonic waves, and the pH gradient control technology is used to make the nutrients in-situ chemically bonded and physically precipitated in the pores, so that the nutrients are fixed in the carriers, and the nutrient leaching loss rate after application is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of organic fruit tree cultivation technology, specifically to an organic fruit tree cultivation method based on the recycling of forestry waste. Background Technology

[0002] Forestry production and orchard management generate a large amount of organic solid waste such as branches, leaves, and sawdust, and the treatment and utilization of this waste remains a continuous challenge for the industry. Meanwhile, modern organic agriculture, especially organic cultivation methods for fruit trees, has a clear technical requirement for cultivation substrates that can improve soil and provide sustained, balanced nutrients.

[0003] Existing methods for utilizing forestry waste mainly include direct return to the field, aerobic composting, and biochar production. Direct return to the field or composting are conventional pathways for converting waste into organic fertilizer. Another pathway is to prepare biochar from waste through pyrolysis, which is then used as a soil conditioner. In some applications, the prepared biochar is physically mixed with fermented compost, or the biochar is directly soaked in nutrient-rich liquids (such as fermentation broth), passively absorbing nutrients through its porous structure.

[0004] However, existing organic cultivation techniques utilizing forestry waste directly returning it to the field suffer from high carbon-to-nitrogen ratios, leading to competition with crops for available nitrogen in the soil during decomposition. Traditional composting suffers from long fermentation cycles and easy nitrogen volatilization and loss. For biochar technology, biochar obtained through conventional high-temperature pyrolysis has few surface functional groups, low chemical activity, and limited chemical adsorption capacity for nutrient molecules. Furthermore, the simple physical mixing or passive soaking methods used to load nutrients result in weak physical adsorption between nutrients and the biochar carrier, leading to easy detachment and rapid loss of nutrients under soil moisture conditions. Therefore, this invention provides an organic cultivation method for fruit trees based on the recycling of forestry waste to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an organic cultivation method for fruit trees based on the recycling of forestry waste, which solves the problems of low nutrient activation efficiency and weak binding force with the carrier, resulting in easy nutrient loss and poor slow-release effect.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an organic cultivation method for fruit trees based on the recycling of forestry waste, comprising the following steps:

[0007] S1. After mixing the nutrient source materials of forestry waste with natural chelating agents and compound microbial agents, anaerobic fermentation is carried out to obtain a liquid phase chelated nutrient solution containing organic chelated nutrients.

[0008] S2. The carbon skeleton source material of forestry waste is subjected to low-temperature pyrolysis under a limited oxygen atmosphere to obtain an active porous carbon skeleton.

[0009] S3. Under vacuum conditions, the active porous carbon skeleton is immersed in the liquid phase chelate nutrient solution and subjected to ultrasonic treatment. An alkaline regulator is added to the liquid phase chelate nutrient solution to slowly raise the pH value from acidic to neutral or weakly alkaline range.

[0010] S4. The mixture containing the active porous carbon skeleton and the liquid chelated nutrient solution is subjected to solid-liquid separation, and the resulting solid material is dried at low temperature to obtain an organic cultivation substrate, which is then applied to the growing soil of fruit trees.

[0011] By adopting the above technical solution, the three stages of nutrient activation, carrier preparation and high-efficiency loading in the waste resource utilization process are systematically integrated, including the following aspects:

[0012] In traditional composting or direct return to the field, the release of mineral nutrients from plant residues is slow and the utilization rate is low. This invention utilizes anaerobic fermentation, employing organic acids and enzymes secreted by compound microbial agents to decompose macromolecular organic matter in nutrient source materials (such as branches and leaves), simultaneously releasing bound mineral elements. Natural chelating agents such as potassium humate are introduced during this process. The carboxyl and phenolic hydroxyl groups on humic acid molecules can chelate with the released metal cations (such as potassium, calcium, magnesium, iron, zinc, and manganese), forming organically chelated nutrients with higher solubility and stronger bioavailability. This process efficiently transfers and enriches the originally solid, poorly soluble nutrients into the liquid phase, preparing a high-concentration nutrient stock solution for subsequent loading steps.

[0013] While biochar prepared by conventional high-temperature (>600℃) pyrolysis is stable, it has fewer surface functional groups, its pores are prone to collapse, and its adsorption activity is relatively low. This invention uses a low-temperature (350~500℃) pyrolysis strategy to treat carbon skeleton source materials (such as sawdust). This temperature range can effectively remove cellulose and hemicellulose, forming rich microporous and mesoporous structures, thereby obtaining high specific surface area and pore volume. At the same time, it can retain the original oxygen-containing functional groups (such as carboxyl, hydroxyl, carbonyl, etc.) in the lignin structure to the maximum extent, or form new active sites during pyrolysis.

[0014] Vacuum-ultrasound synergistic enhancement of mass transfer: By effectively removing trapped air from the micropores of the active porous carbon framework through vacuuming, the air resistance effect is eliminated, creating an unobstructed channel for the entry of liquid nutrient solution. Subsequently, the nutrient solution is immersed and ultrasound is applied. The microjets and strong disturbances generated by the ultrasonic cavitation effect can force and deeply transport chelated nutrient molecules in the liquid phase into the inner pores of the carbon framework, achieving uniformity and maximization of the load, and solving the problems of shallow loading depth and low efficiency of conventional impregnation methods.

[0015] pH gradient chemical anchoring: After physical loading is complete, an alkaline regulator (such as wood ash leachate) is slowly added dropwise. This process establishes a pH gradient from acidic to neutral. Under initial acidic conditions, chelated nutrients are stably dissolved in the liquid phase, and as the pH slowly increases:

[0016] On the one hand, the oxygen-containing functional groups (-COOH) on the surface of the carbon skeleton are deprotonated into -COO. - The increased surface negative charge enhances the electrostatic adsorption of metal cations;

[0017] On the other hand, the stability of some metal-humic acid chelates decreases with increasing pH, or they may hydrolyze directly, promoting the in-situ precipitation or chemical bonding of nutrients within the pores of the carbon skeleton in the form of hydroxides, carbonates, or functional groups. Because the pH increases slowly, rapid nutrient precipitation within the system is avoided; instead, it preferentially occurs at the interfaces that have already entered the pores, thus anchoring the nutrients within the carrier.

[0018] Preferably, in the step of performing anaerobic fermentation to obtain liquid-phase chelated nutrient solution, the natural chelating agent is potassium humate, and the mass ratio of the nutrient source material, deionized water, and potassium humate is 100:300-500:1.0-3.0.

[0019] By adopting the above technical solution, this ratio range can ensure that there is sufficient liquid medium and sufficient chelating agent during the fermentation process, so as to achieve efficient dissolution and activation of mineral elements in the nutrient source material.

[0020] Preferably, in the step of performing anaerobic fermentation to obtain liquid-phase chelated nutrient solution, the temperature of the anaerobic fermentation is 25-35°C, the fermentation time is 7-10 days, the compound microbial agent includes Lactobacillus plantarum, Saccharomyces cerevisiae and Rhodopseudomonas palustris, and the mass ratio of the nutrient source material to the compound microbial agent is 100:0.5-1.0.

[0021] By adopting the above technical solutions, the process parameters and bacterial agent composition provide suitable conditions for the growth, reproduction and metabolic acid production of microorganisms, and the synergistic effect can accelerate the decomposition of organic matter and the release of nutrients.

[0022] Preferably, before the anaerobic fermentation and the low-temperature pyrolysis, a pretreatment step of pulverizing the nutrient source material and the carbon skeleton source material is included, wherein the particle size of the nutrient source material is controlled at 5-10 mm and the particle size of the carbon skeleton source material is controlled at 10-20 mm.

[0023] By adopting the above technical solution, the raw materials are appropriately pulverized, which increases the specific surface area of ​​the materials and is beneficial to improving the reaction rate and uniformity of subsequent fermentation and pyrolysis processes.

[0024] Preferably, in the step of performing low-temperature pyrolysis, the temperature is increased to a target temperature of 350-500°C at a heating rate of 5-15°C / min, and then held at the target temperature for 1-2 hours.

[0025] By adopting the above technical solution, the combination of pyrolysis parameters is the optimized condition for forming an active porous carbon framework with both high porosity and abundant surface functional groups.

[0026] Preferably, in the loading and anchoring steps, a vacuum is drawn to -0.08 to -0.095 MPa and maintained for 15 to 30 minutes; ultrasonic treatment is performed for 30 to 60 minutes; and the pH value of the liquid-phase chelated nutrient solution is increased from the initial range of 5.2 to 5.8 to the final range of 7.0 to 7.5 within 2 to 4 hours.

[0027] By adopting the above technical solutions, specific and optimized operating parameters are provided for the multi-physics field enhanced loading and chemical anchoring process, ensuring the efficiency of nutrient loading and the slow-release performance of the final product.

[0028] Preferably, the frequency of the ultrasonic treatment is 20-40 kHz, the power intensity is 50-100 W / L, and the alkaline regulator is wood ash leachate.

[0029] By adopting the above technical solution, the ultrasonic parameters within this range effectively generate cavitation effect. Wood ash leachate is used as an alkaline regulator, which is widely available and inexpensive. Its rich potassium, calcium and other fast-acting nutrients can also supplement and enhance the matrix.

[0030] Preferably, the plant ash leachate is prepared by the following method: plant straw is ashed at 600°C, the resulting plant ash is ground and passed through a 100-mesh sieve, then mixed with water at a mass-volume ratio of 1:10, stirred and allowed to stand, and then filtered to obtain the filtrate.

[0031] By adopting the above technical solution, the preparation process of alkaline regulators has been standardized, ensuring the relative stability of their pH value and active ingredients, thereby ensuring the repeatability of the pH gradient anchoring process.

[0032] Preferably, in the step of preparing the matrix product, the moist solid material is dried at a low temperature of 60-80°C until the final moisture content is less than 15%.

[0033] By adopting the above technical solution, low-temperature drying can effectively remove excess moisture, which is convenient for product storage and transportation, while avoiding the damage of high temperature to the loaded nutrients and carbon skeleton surface active sites.

[0034] Preferably, the step of applying the organic cultivation substrate to the growing soil of the fruit trees can be used as a base fertilizer, mixed with the soil in the planting hole when the fruit trees are planted; or as a top dressing, applied to the root zone soil along the edge of the tree canopy projection by trenching, digging holes or spreading on the ground.

[0035] By adopting the above technical solution, the specific application of this organic cultivation substrate in agricultural production has been clarified, thereby enabling flexible adaptation to the nutrient requirements of fruit trees at different growth stages.

[0036] This invention provides a method for organic fruit tree cultivation based on the recycling of forestry waste. It has the following beneficial effects:

[0037] 1. This invention utilizes the synergistic effect of vacuum and ultrasound to transport chelated nutrients into the interior of an active porous carbon framework during the loading and anchoring steps. It also employs pH gradient control technology to enable in-situ chemical bonding and physical precipitation of nutrients within the pores, thereby immobilizing the nutrients in the carrier, improving the slow-release performance of nutrients, and effectively reducing the nutrient leaching loss rate after application.

[0038] 2. This invention uses a low-temperature pyrolysis process to prepare an active porous carbon framework. This process preserves the rich natural multi-level pore structure of biomass materials, forming a carrier with high pore volume and high specific surface area. The resulting organic cultivation substrate has excellent water retention capacity and can be used as a long-lasting soil physical conditioner to improve the soil's water and fertilizer retention performance.

[0039] 3. This invention achieves functional division and synergistic utilization of two different types of forestry waste. First, through anaerobic fermentation and chelation, the solid, insoluble nutrients in the nutrient source material are efficiently activated and transferred to the liquid phase. Subsequently, a porous carrier prepared from a carbon skeleton source material is used to load these liquid phase nutrients. This achieves efficient activation and enrichment of nutrients, improves the bioavailability of the final product, and complements the advantages of different wastes, thereby enhancing the overall value. Attached Figure Description

[0040] Figure 1 This is a flowchart of the method steps of the present invention; Detailed Implementation

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0043] Potassium humate, CAS No.: 68514-28-3;

[0044] The compound microbial agent is a commercial-grade EM-type compound microbial agent stock solution, and its main active bacterial strains include:

[0045] Lactobacillus plantarum, accession number GDMCC No. 61306;

[0046] Saccharomyces cerevisiae, accession number CGMCC 2.10;

[0047] The accession number for *Rhodopseudomonas palustris* is CGMCC 1.2181.

[0048] The wood ash leachate is a self-prepared reagent used to adjust the pH value. The detailed preparation method is described in the preparation example section.

[0049] Nitrogen, CAS No.: 7727-37-9;

[0050] Sodium hydroxide, CAS No.: 1310-73-2;

[0051] Sodium carbonate, CAS No.: 497-19-8;

[0052] Sodium bicarbonate, CAS No.: 144-55-8.

[0053] The following preparation examples are used to prepare the wood ash leachate used in the embodiments of the present invention.

[0054] Preparation example:

[0055] Dry straw was placed in a well-ventilated muffle furnace and thoroughly ashed at 600°C for 4 hours to obtain wood ash. After naturally cooling to room temperature, it was removed, ground, and passed through a 100-mesh sieve to obtain a uniform ash powder. The wood ash powder was accurately weighed and added to deionized water at a mass-to-volume ratio (w / v) of 1:10, i.e., 100 grams of wood ash powder to 1000 ml of deionized water. The mixture was stirred continuously with a magnetic stirrer at room temperature for 30 minutes, followed by standing precipitation for 24 hours. After precipitation, the supernatant was carefully decanted and filtered using medium-speed qualitative filter paper. The resulting clear filtrate is the wood ash leachate, with a pH value of 10.5–11.5. The leachate was sealed in a clean polyethylene bottle and stored at room temperature away from light for later use.

[0056] Please see the appendix Figure 1 Examples 1-3.

[0057] Example 1:

[0058] This embodiment provides a method for organic fruit tree cultivation based on the recycling of forestry waste, including the following steps:

[0059] S1. Take a mixture of air-dried apple tree tender branches and leaves as a nutrient source, crush it, and sieve it to collect materials with a particle size of 5-10 mm. In an anaerobic fermenter, mix 100 parts by weight of the material, 400 parts by weight of deionized water, 2.0 parts by weight of potassium humate powder and 0.7 parts by weight of compound microbial inoculant stock solution evenly, and seal and ferment at 30°C for 8 days to obtain liquid phase chelated nutrient solution.

[0060] S2. Take the air-dried pine sawdust mixture as the carbon skeleton source, crush it and collect the material with a particle size of 10-20 mm, place it in an oxygen-limited pyrolysis furnace, and heat it to 425 °C at a rate of 10 °C / min under a nitrogen protective atmosphere, and keep it at this temperature for 1.5 hours. After natural cooling, an active porous carbon skeleton is obtained.

[0061] S3. Place the prepared active porous carbon skeleton in a vacuum impregnation ultrasonic reactor, evacuate to -0.09 MPa and maintain pressure for 20 minutes, and draw in the prepared liquid-phase chelated nutrient solution until the material is completely submerged. Start the ultrasonic system and treat for 45 minutes at a frequency of 30 kHz and a power intensity of 75 W / L. Slowly add the wood ash leachate prepared in the preparation example over 3 hours using a peristaltic pump to uniformly raise the pH value of the liquid in the reactor from 5.5 to 7.2.

[0062] S4. Drain excess liquid from the reactor and transfer the moist solid material to an electric heating drying oven. Dry the material at 70°C until the moisture content is below 15%, thus obtaining the multifunctional organic cultivation substrate product.

[0063] Example 2:

[0064] This embodiment provides a method for organic fruit tree cultivation based on the recycling of forestry waste, including the following steps:

[0065] S1. A mixture of air-dried apple tree twigs and leaves is used as a nutrient source. After crushing, the material with a particle size of 5-10 mm is collected by sieving. In an anaerobic fermenter, 100 parts by weight of the material, 300 parts by weight of deionized water, 1.0 part by weight of potassium humate powder, and 0.5 parts by weight of compound microbial inoculant stock solution are mixed evenly and fermented in a sealed container at 25°C for 7 days to obtain a liquid-phase chelated nutrient solution.

[0066] S2. Take the air-dried pine sawdust mixture as the carbon skeleton source, crush it and collect the material with a particle size of 10-20mm, place it in an oxygen-limited pyrolysis furnace, and heat it to 350℃ at a rate of 5℃ / min under a nitrogen protective atmosphere, and keep it at this temperature for 1 hour. After natural cooling, an active porous carbon skeleton is obtained.

[0067] S3. Place the prepared active porous carbon framework in a vacuum impregnation ultrasonic reactor, evacuate to -0.08 MPa and maintain the pressure for 15 minutes, then draw in the prepared liquid-phase chelated nutrient solution until the material is completely submerged. Start the ultrasonic system and treat for 30 minutes at a frequency of 20 kHz and a power intensity of 50 W / L. Slowly add the wood ash leachate prepared in the preparation example over 2 hours using a peristaltic pump to uniformly raise the pH value of the liquid in the reactor from 5.8 to 7.0.

[0068] S4. Drain excess liquid from the reactor and transfer the moist solid material to an electric heating drying oven. Dry the material at 60°C until the moisture content is less than 15%, thus obtaining the multifunctional organic cultivation substrate product.

[0069] Example 3:

[0070] This embodiment provides a method for organic fruit tree cultivation based on the recycling of forestry waste, including the following steps:

[0071] S1. Take a mixture of air-dried apple tree tender branches and leaves as a nutrient source, crush it, and sieve it to collect materials with a particle size of 5-10 mm. In an anaerobic fermenter, mix 100 parts by weight of the material, 500 parts by weight of deionized water, 3.0 parts by weight of potassium humate powder and 1.0 parts by weight of compound microbial inoculant stock solution evenly, and seal and ferment at 35°C for 10 days to obtain liquid phase chelated nutrient solution.

[0072] S2. Take the air-dried pine sawdust mixture as the carbon skeleton source, crush it and collect the material with a particle size of 10-20mm, place it in an oxygen-limited pyrolysis furnace, and heat it to 500℃ at a rate of 15℃ / min under a nitrogen protective atmosphere, and keep it at this temperature for 2 hours. After natural cooling, an active porous carbon skeleton is obtained.

[0073] S3. The prepared active porous carbon framework was placed in a vacuum impregnation ultrasonic reactor, and a vacuum was drawn to -0.095 MPa and maintained for 30 minutes. The prepared liquid-phase chelated nutrient solution was then drawn in until the material was completely submerged. The ultrasonic system was started and treated for 60 minutes at a frequency of 40 kHz and a power intensity of 100 W / L. Subsequently, the wood ash leachate prepared in the preparation example was slowly added dropwise over 4 hours using a peristaltic pump to uniformly raise the pH value of the liquid in the reactor from 5.2 to 7.5.

[0074] S4. Drain excess liquid from the reactor and transfer the moist solid material to an electric heating drying oven. Dry the material at 80°C until the moisture content is below 15%, thus obtaining the multifunctional organic cultivation substrate product.

[0075] Comparative Example 1:

[0076] Compared with Example 1, the difference is that the nutrient source material is subjected to traditional aerobic composting for 45 days, the carbon skeleton source material is pyrolyzed at 700°C to prepare inert biochar, and the two dry-based products are physically mixed to obtain the final product.

[0077] Comparative Example 2:

[0078] Compared with Example 1, the difference is that potassium humate is not added in the process of preparing the liquid nutrient solution, but all other aspects are the same.

[0079] Comparative Example 3:

[0080] Compared with Example 1, the difference is that the target pyrolysis temperature is 700°C during the preparation of the carbon skeleton, while the rest are the same.

[0081] Comparative Example 4:

[0082] Compared with Example 1, the difference is that no ultrasonic treatment is performed during the loading process, and the vacuum impregnation is followed by a 45-minute resting time. All other aspects are the same.

[0083] Comparative Example 5:

[0084] Compared with Example 1, the difference is that after the loading process, the pH gradient anchoring step of adding wood ash leachate is not performed; otherwise, they are the same.

[0085] Comparative Example 6:

[0086] Compared with Example 1, the difference is that no vacuuming step is performed during the loading process. The active porous carbon skeleton is directly immersed in the liquid phase chelation nutrient solution under normal pressure. All other aspects are the same.

[0087] Test Examples 1-3.

[0088] Test Example 1:

[0089] Experimental description: The total nutrient content in the sample of the example and each comparative example was determined by acid digestion-inductively coupled plasma optical emission spectrometry (ICP-OES).

[0090] Experimental steps:

[0091] Sample pretreatment: All final product samples obtained in Examples 1-3 and Comparative Examples 1-6 were dried to constant weight in an electric heating drying oven at 60°C, and then cooled to room temperature in a desiccator.

[0092] Weighing and Digestion: Accurately weigh approximately 0.5 g of the dried sample and place it in a polytetrafluoroethylene (PTFE) digestion tube. Add 10 mL of analytical grade nitric acid (HNO3), cap the tube, and pre-react at room temperature for 12 hours. Remove the cap and place the digestion tube on a programmable temperature-controlled graphite digester. Proceed with the temperature program: first heat at 120°C for 1 hour, then at 160°C for 2 hours, and finally heat to 180°C until approximately 1-2 mL of liquid remains in the tube. Remove the digestion tube, cool it, add 2 mL of hydrogen peroxide (H2O2), and heat again at 160°C until the liquid is clear and transparent.

[0093] Volume adjustment and analysis: After the digestion tube has completely cooled, rinse the tube walls with deionized water in small amounts several times, and transfer all the digested solution to a 50 mL Grade A volumetric flask. Dilute to the mark with deionized water and mix well. Determine the concentrations of potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) in the solution using inductively coupled plasma optical emission spectrometry (ICP-OES). Simultaneously prepare a blank sample and perform the same digestion and analysis procedure.

[0094] Content calculation: Based on the measured element concentration, sample dilution factor and initial sample mass, the total content of each element in the original dry basis sample is calculated.

[0095] Experimental data (see Table 1):

[0096] Table 1: Total nutrient content of each example and comparative product

[0097] Sample number K(g / kg) Ca (g / kg) Mg (g / kg) Fe (mg / kg) Mn (mg / kg) Zn (mg / kg) Example 1 21.3 15.8 6.4 1255 412 115 Example 2 18.9 13.5 5.1 1080 358 98 Example 3 24.6 17.2 7.9 1432 485 134 Comparative Example 1 15.2 11.8 4.6 970 321 85 Comparative Example 2 8.7 6.1 2.5 624 188 53 Comparative Example 3 14.1 10.3 4.2 855 290 76 Comparative Example 4 16.5 11.9 4.8 980 341 88 Comparative Example 5 19.8 14.2 5.9 1165 385 104 Comparative Example 6 11.4 8.5 3.3 710 235 61

[0098] in conclusion:

[0099] The data in Table 1 show that the total content of key nutrients (K, Ca, Mg) and trace elements (Fe, Mn, Zn) in Examples 1, 2, and 3 prepared by the method of the present invention is higher than that in most comparative products.

[0100] Data analysis revealed the synergistic effect of various technical features in this invention. Comparative Example 2 (without potassium humate) had the lowest nutrient content, confirming that potassium humate's solubilizing and chelating effect on mineral elements in the "nutrient source" during fermentation is fundamental to achieving high-efficiency nutrient enrichment. The results of Comparative Examples 3, 4, and 6 collectively verified the effectiveness of the integrated loading process: compared to Comparative Example 3 (high-temperature inert carbon), the activated carbon framework obtained by low-temperature pyrolysis in this invention exhibits superior loading performance; compared to Comparative Examples 4 (without ultrasound) and 6 (without vacuum), the combined vacuum and ultrasonic treatment significantly improved the mass transfer efficiency and loading depth of nutrients from the liquid phase to the solid carrier. Although the nutrient content of Comparative Example 5 (without pH anchoring) was higher than most other comparative examples, it was lower than that of Example 1, indicating that the pH gradient anchoring step plays a crucial role in the solidification of the loaded nutrients and preventing their loss in subsequent processing.

[0101] Test Example 2:

[0102] Experimental description: A dynamic leaching experiment was conducted using soil columns to simulate the release and loss behavior of nutrients after application to the samples in the examples and comparative examples.

[0103] Experimental steps:

[0104] Preparation of the rinsing column: An acrylic glass column with an inner diameter of 5 cm and a height of 30 cm was selected as the rinsing column. A layer of nylon mesh and a layer of quartz wool were laid at the bottom of the column, and then 200 g of quartz sand that had been acid-washed and calcined at high temperature was filled in. 10 g of the sample to be tested (the final product of Examples 1-3 and Comparative Examples 1-6) was accurately weighed, mixed evenly with 100 g of quartz sand, and then laid on the quartz sand layer in the middle of the rinsing column, and then covered with 50 g of quartz sand on top.

[0105] Dynamic rinsing: On days 1, 3, 7, 15, 30 and 45 after the start of the experiment, 100 ml of deionized water was slowly added to the top of each rinsing column to simulate a rainfall event. All the leachate flowing out from the bottom of the column was collected and its volume was recorded.

[0106] Sample Analysis: The leachate samples collected at each time point were filtered through a 0.45-micron filter membrane. The concentrations of potassium (K), calcium (Ca), and magnesium (Mg) in the filtrate were determined using inductively coupled plasma optical emission spectrometry (ICP-OES).

[0107] Data processing: Based on the measured element concentrations and leachate volumes, the cumulative release rate of each nutrient in each leaching event is calculated. The cumulative release rate (%) = (total mass of a certain nutrient in all leachates up to the current time point / initial total mass of that nutrient in the sample) × 100%.

[0108] Experimental data (see Table 2):

[0109] Table 2: Cumulative potassium release rate of each example and comparative product in simulated rinsing experiment

[0110] Sample number Day 1 Day 3 Day 7 Day 15 Day 30 Day 45 Example 1 4.8 8.9 15.2 24.1 35.6 45.3 Example 2 5.5 10.1 17.8 27.2 39.1 49.5 Example 3 4.1 7.5 13.1 21.5 32.8 42.1 Comparative Example 1 25.3 41.2 56.8 65.1 68.3 69.8 Comparative Example 2 35.8 55.4 69.3 75.8 78.2 79.1 Comparative Example 3 28.1 45.9 60.2 68.7 71.5 72.8 Comparative Example 4 12.6 20.1 31.5 42.8 53.6 60.7 Comparative Example 5 19.5 32.7 48.6 59.1 65.4 68.2 Comparative Example 6 31.2 50.8 65.9 72.3 75.1 76.4

[0111] in conclusion:

[0112] The data in Table 2 show that the cumulative nutrient release curves of Examples 1, 2, and 3 all exhibit a gradual and continuous growth trend. Throughout the 45-day experimental period, the nutrient release rate remained relatively stable, without any obvious initial burst of release. This indicates that the matrix prepared in this invention can effectively retain nutrients and supply them in a slow and sustained manner.

[0113] In contrast, all comparative examples exhibited varying degrees of rapid release issues. Comparative Example 1 (physical mixing), Comparative Example 2 (no chelation), Comparative Example 3 (high-temperature char), and Comparative Example 6 (atmospheric pressure impregnation) released more than 50% of the total nutrients in the initial stage of the experiment (first 7 days), showing obvious release characteristics, indicating that most nutrients would be rapidly lost in practical applications. Although the sustained-release performance of Comparative Example 4 (no ultrasound) and Comparative Example 5 (no pH anchoring) was better than the aforementioned comparative examples, their initial release rate and final cumulative release amount were still significantly higher than those of Example 1.

[0114] Chelation (Comparative Example 1 and Comparative Example 2) is a prerequisite for forming a stable nutrient form; low-temperature activated carbon skeleton (Comparative Example 1 and Comparative Example 3) provides active sites for nutrient binding; and the combination of vacuum ultrasonic loading (Comparative Example 1 and Comparative Examples 4 and 6) and pH gradient anchoring (Comparative Example 1 and Comparative Example 5) locks nutrients firmly in the porous structure of the carbon skeleton through physicochemical action, realizing controlled slow release of nutrients. This slow release mechanism effectively avoids the problem of excessive nutrient loss in the early stage of application of traditional organic fertilizers or loaded fertilizers.

[0115] Test Example 3:

[0116] Experimental description: The water retention capacity of each example and each comparative sample was evaluated using the saturated water holding capacity determination method.

[0117] The experimental steps are as follows:

[0118] Sample preparation: All final products of Examples 1-3 and Comparative Examples 1-6 were dried to constant weight in an electric heating drying oven at 60°C, and their dry weight was recorded.

[0119] Saturation water absorption: Take a round qualitative filter paper of known dry weight and moisten it in a Buchner funnel. Spread 10 grams of the dry sample evenly on the filter paper. Slowly add deionized water to the funnel until the water level just submerges the sample layer, and let it stand for 24 hours to achieve saturation water absorption.

[0120] Remove gravity water: After saturation, stop adding water and allow the sample to drain naturally under gravity for 30 minutes to remove excess gravity water from the pores.

[0121] Weighing the wet weight: After no more water drips, quickly weigh the total weight of the Buchner funnel containing the saturated water-absorbing sample, and subtract the weight of the pre-determined wetted Buchner funnel and filter paper to obtain the saturated wet weight of the sample.

[0122] Calculation: Calculate the maximum water holding capacity of the product, which represents the mass of water that a unit mass of dry sample can hold.

[0123] Experimental data (see Table 3):

[0124] Table 3: Maximum water holding capacity of each embodiment and comparative product

[0125] Sample number Maximum water holding capacity (g / g) Example 1 3.51 Example 2 3.42 Example 3 3.68 Comparative Example 1 2.26 Comparative Example 2 3.25 Comparative Example 3 2.38 Comparative Example 4 3.31 Comparative Example 5 3.45 Comparative Example 6 2.67

[0126] in conclusion:

[0127] The data in Table 3 show that the water retention performance of the product is mainly determined by its physical structure, especially its porosity and pore size distribution. The low-temperature pyrolysis process (350-500℃) used in this invention enables lignocellulose to form abundant micropores and mesopores under incomplete carbonization, thereby constructing an active porous carbon skeleton with high specific surface area and total pore volume. This is the physical basis for the high water retention of the products in the examples.

[0128] In contrast, Comparative Examples 1 and 3 employed high-temperature (700℃) pyrolysis. The excessively high temperature caused a degree of collapse and sintering in the porous structure of the carbon skeleton, resulting in a decrease in total pore volume and thus a significant reduction in its water retention capacity. Comparative Example 6 (atmospheric pressure impregnation) also exhibited significantly lower water retention capacity. This was because the untreated carbon skeleton contained a large amount of bound air within its micropores, and the air resistance effect hindered moisture entry, leading to a reduction in effective water-holding pores. While the water retention capacities of Comparative Examples 2, 4, and 5 were close to those of the embodiments, they still showed differences, indicating that complete process steps have a synergistic effect in maximizing the physical properties of the product.

[0129] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An organic cultivation method for fruit trees based on the recycling of forestry waste, characterized in that, Includes the following steps: S1. The nutrient source material of forestry waste is mixed with natural chelating agent and compound microbial agent and then subjected to anaerobic fermentation to obtain liquid phase chelated nutrient solution containing organic chelated nutrients. The natural chelating agent is potassium humate. S2. The carbon skeleton source material of forestry waste is heated to a target temperature of 350-500℃ under an oxygen-limited atmosphere at a heating rate of 5-15℃ / min to obtain an active porous carbon skeleton. S3. Under vacuum conditions, the active porous carbon skeleton is immersed in the liquid phase chelate nutrient solution and subjected to ultrasonic treatment. An alkaline regulator is added to the liquid phase chelate nutrient solution to slowly raise the pH value from acidic to neutral or weakly alkaline range. S4. The mixture containing the active porous carbon skeleton and the liquid chelated nutrient solution is subjected to solid-liquid separation, and the resulting solid material is dried at low temperature to obtain an organic cultivation substrate, which is then applied to the growing soil of the fruit trees. Step S4 further includes: The mixture of the active porous carbon framework and the liquid-phase chelated nutrient solution is subjected to solid-liquid separation to obtain a moist solid material. The moist solid material is dried by hot air circulation at a temperature of 60-80°C until the final moisture content is less than 15%.

2. The method for organic fruit tree cultivation based on the recycling of forestry waste according to claim 1, characterized in that, In step S1, the mass ratio of the nutrient source material, deionized water, and potassium humate is 100:300-500:1.0-3.

0.

3. The method for organic fruit tree cultivation based on the recycling of forestry waste according to claim 1, characterized in that, In step S1, obtaining the liquid-phase chelated nutrient solution containing organic chelated nutrients further includes: The anaerobic fermentation temperature is 25–35℃, and the fermentation time is 7–10 days; The compound microbial agent includes Lactobacillus plantarum, Saccharomyces cerevisiae, and Rhodopseudomonas palustris; The mass ratio of the nutrient source material to the compound microbial agent is 100:0.5 to 1.

0.

4. The forestry waste recycling-based organic cultivation method of fruit trees according to claim 1, characterized by, Before the anaerobic fermentation and low-temperature pyrolysis, the nutrient source material and the carbon skeleton source material are pre-treated by crushing. The particle size of the nutrient source material is controlled at 5-10 mm, and the particle size of the carbon skeleton source material is controlled at 10-20 mm.

5. The forestry waste recycling-based organic cultivation method of fruit trees according to claim 1, characterized by, Step S2 further includes: The carbon skeleton source material is placed in a pyrolysis furnace, and nitrogen is introduced into the furnace to expel air and form an oxygen-limited protective atmosphere. Set and execute the pyrolysis procedure, hold the temperature at the target temperature for 1 to 2 hours, then stop heating and allow the carbon skeleton source material to cool naturally under the oxygen-limited protective atmosphere.

6. The method for organic fruit tree cultivation based on the recycling of forestry waste according to claim 1, characterized in that, Step S3 further includes: The active porous carbon framework was placed in a reaction vessel, and a vacuum was drawn to -0.08 to -0.095 MPa and maintained for 15 to 30 minutes. The active porous carbon skeleton is then immersed in the liquid-phase chelated nutrient solution and subjected to ultrasonic treatment for 30–60 minutes. After ultrasonic treatment, the alkaline regulator is slowly added dropwise to the liquid-phase chelated nutrient solution over 2 to 4 hours to raise the pH value of the liquid-phase chelated nutrient solution from the initial range of 5.2 to 5.8 to the final range of 7.0 to 7.

5.

7. The method for organic fruit tree cultivation based on the recycling of forestry waste according to claim 6, characterized in that, The ultrasonic treatment has a frequency of 20–40 kHz and a power intensity of 50–100 W / L, and the alkaline regulator is wood ash leachate.

8. The organic fruit tree cultivation method based on recycling of forestry waste according to claim 7, characterized in that, The preparation steps of the plant ash leachate include: Plant straw was ashed at 600℃, cooled, and the resulting plant ash was ground and passed through a 100-mesh sieve to obtain plant ash powder. The obtained plant ash powder is mixed with water at a mass-volume ratio of 1:10, stirred, and allowed to settle. The supernatant is taken and filtered, and the resulting filtrate is the plant ash leachate.

9. The method for organic fruit tree cultivation based on the recycling of forestry waste according to claim 1, characterized in that, In step S4, applying the organic cultivation substrate to the growing soil of the fruit trees further includes: As a base fertilizer, the organic cultivation substrate is mixed with the soil in the planting hole of the fruit tree and then used for planting the fruit tree. As a top dressing, the organic cultivation substrate is applied to the root zone soil along the edge of the tree canopy projection by trenching or digging holes, or directly spread on the surface of the soil around the roots of the fruit trees.

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