A method for the production of a nutrient-rich bioculture substrate

Abstract

The application discloses a preparation method of a nutrient-rich biological cultivation substrate, and steps include: taking biomass raw materials, processing and treating to obtain biomass charcoal powder; preparing a composite nutrient solution, taking the biomass charcoal powder to soak in the composite nutrient solution, taking the biomass charcoal powder to dry after soaking is completed; mechanically grinding the biomass charcoal powder; performing a heat treatment process of heating-keeping warm-cooling on the biomass charcoal powder to make the pores of the biomass charcoal powder shrink; and taking the biomass charcoal powder to make particles with a set size. The application takes the biomass charcoal powder as a carrier, adopts a specific combined process of loading the nutrient solution, mechanical grinding and heat treatment, so that the nutrients are fully loaded in the pores of the charcoal powder, the nutrient release rate is reduced after the pores shrink in the heat treatment, the nutrient retention capacity is improved and the release is balanced, meanwhile, the granular substrate has excellent ventilation and drainage performance, which is very beneficial to soilless cultivation management of plants.

Description

Technical Field

[0001] This invention relates to the field of soilless cultivation technology, specifically to a method for preparing a nutrient-rich biological cultivation substrate. Background Technology

[0002] Soilless cultivation is a highly efficient, environmentally friendly, and economical agricultural production method with broad application prospects and development potential. The main types of soilless cultivation include hydroponics, aeroponics, and substrate culture. Among these, substrate culture involves fixing the crop's root system in an organic or inorganic substrate and supplying the crop with nutrient solution through drip irrigation or fine-flow irrigation. It offers advantages such as high air permeability, water and fertilizer conservation, and cleanliness without pollution.

[0003] Traditional substrate cultivation primarily uses inorganic substrates such as sand, gravel, rock wool, perlite, and vermiculite, as well as organic substrates such as bark, bagasse, rice residue, peat, rice husk charcoal, and sawdust. The nutrients in these substrates are mainly derived from organic matter, which is quite limited. Therefore, nutrient solutions are needed during cultivation to supply the plants with the necessary nutrients, inevitably increasing labor costs. With the continuous development of soilless cultivation technology, more and more new cultivation substrates are being developed and applied, such as substrates made from agricultural waste (such as mushroom compost, chicken manure, and pig manure) through composting and fermentation. These substrates are rich in nutrients, but they lose their original advantages such as permeability, and the nutrient release is rapid and uneven, easily leading to excessive nutrients in the early stages of cultivation and insufficient nutrients in the later stages, which is detrimental to plant growth. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a nutrient-rich biological cultivation substrate, which solves the problems of limited nutrients in traditional cultivation substrates and poor air permeability, rapid and uneven nutrient release in novel agricultural waste fermentation substrates.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0007] S1. Take the cleaned and dried biomass raw material and process it to obtain biochar powder;

[0008] S2. Prepare a compound nutrient solution. Soak biomass char powder in the compound nutrient solution. After soaking, take out the biomass char powder and let it dry so that the compound nutrient solution is loaded on the outer surface and pores of the biomass char powder.

[0009] The ingredients for the compound nutrient solution, by weight, include 35-45 parts potassium sulfate, 2-5 parts potassium chloride, 10-20 parts calcium phosphate, 15-25 parts calcium sulfate, 16-20 parts calcium nitrate, 4-8 parts magnesium sulfate, and 220-280 parts water.

[0010] S3. Mechanically grind the biomass charcoal powder to remove the composite nutrient solution loaded on the outer surface of the biomass charcoal powder and expose the charcoal layer.

[0011] S4. The biochar powder undergoes a heat treatment process of heating, holding, and cooling to shrink the pores of the biochar powder.

[0012] The heating rate is 3-8℃ / min, the holding temperature is 500-600℃, the holding time is 60-300min, the cooling rate is 0.5-2℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 10-15:1.

[0013] S5. Take biochar powder and make it into particles of a set size to obtain the bio-cultivation substrate.

[0014] A further improvement is that, in step S1, the biomass raw material is selected from one of bamboo, wood, coconut shell, rice husk, or straw.

[0015] A further improvement is that, in step S1, the processing refers to first carbonizing at 550-650℃ for 1-2 hours in a carbonization furnace, and then activating at 800-900℃ for 6-15 hours in an activation furnace.

[0016] A further improvement is that, in step S2, the biomass carbon powder is soaked in the composite nutrient solution for 6-12 hours, the weight ratio of biomass carbon powder to composite nutrient solution is 1:5-8, and ultrasonic oscillation treatment is applied to the composite nutrient solution during the soaking process, with an ultrasonic frequency of 18-25kHz and an ultrasonic power of 350-400W.

[0017] A further improvement is that, in step S3, the mechanical grinding refers to placing the biomass carbon powder in a zirconia ball mill and grinding it at a speed of 100-150 rpm for 1-2 hours.

[0018] A further improvement is that, in step S4, the volume ratio of nitrogen to oxygen is 13:1.

[0019] A further improvement is that, in step S5, the process of producing granules of a set size refers to: taking biochar powder, controlling its humidity at 8-12% by spraying, pressing the biochar powder into granules using a pelletizer, and finally sieving and drying the granules.

[0020] A further improvement is that, in step S5, the particles consist of two sizes: large particles of 6±0.2mm and small particles of 2±0.2mm, and the weight ratio between the large particles and the small particles is 3:2.

[0021] The beneficial effects of this invention are as follows:

[0022] (1) This invention uses biochar powder as a carrier and adopts a specific combination process of loading nutrient solution, mechanical grinding and heat treatment, so that nutrients are first fully loaded by the pores of the char powder, and the pores shrink after heat treatment, which reduces the nutrient release rate, improves the nutrient retention capacity and releases evenly. At the same time, the granular matrix has excellent aeration and drainage performance, which is very beneficial to the soilless cultivation management of plants.

[0023] The purpose of mechanical grinding is to peel off the composite nutrient solution loaded on the outer surface of biochar powder and expose the carbon layer. The grinding speed and time are relatively low, so it will not cause unnecessary damage to the carbon powder. The heat treatment of heating-holding-cooling causes the carbon powder surface to expand and contract, as well as the carbon atom bonding and rearrangement process. The maximum treatment temperature is below 600℃, which can ensure the treatment effect without causing the decomposition and failure of the inorganic salt nutrients used. The cooling rate is slow, reducing the generation of thermal stress and preventing the carbon powder from cracking. At the same time, under a nitrogen and oxygen atmosphere with a specific ratio of 10-15:1 (especially 13:1), the exposed carbon layer can undergo a certain oxidation reaction, causing oxide deposition at the pore openings without completely blocking the pores. Under the combined effect of the above series of factors, the pores on the carbon powder surface shrink, the nutrient leaching rate decreases, and becomes more uniform.

[0024] (2) The biological cultivation substrate of the present invention uses a combination of two different particle sizes, which can maintain good aeration and drainage performance, improve the nutrient retention and supply capacity of the substrate, enhance structural stability, prevent substrate clumping or hardening, and optimize the root growth environment. Attached Figure Description

[0025] Figure 1 A graph showing the results of plant height growth of African violet seedlings;

[0026] Figure 2 A graph showing the crown growth of African violet seedlings;

[0027] Figure 3 This is a graph showing the leaf number growth of African violet seedlings. Detailed Implementation

[0028] The present application will be further described in detail below with reference to specific embodiments. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0029] I. Experimental Apparatus

[0030] The following equipment was used: Nabertherm's LHT 02 / 17 LB series carbonization furnace; Carbolite Gero's CWF 1200 activation furnace; Qsonica's Q700 ultrasonic oscillator; Fritsch's Pulverisette 7 Premium Line ball mill; Nabertherm's LHT 02 / 17 LB high-temperature furnace; Labplant's SD-6 spray dryer; FEECO International's double-roll pellet mill; and Sieve Technologies' SY-600 vibrating screen.

[0031] II. Experimental Methods

[0032] Example 1: A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0033] S1. Take the bamboo and wood powder after removing impurities and drying, first carbonize it in a carbonization furnace at 550℃ for 2 hours, and then activate it in an activation furnace at 800℃ for 15 hours to obtain biomass char powder.

[0034] S2. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 35 parts potassium sulfate, 2 parts potassium chloride, 10 parts calcium phosphate, 15 parts calcium sulfate, 16 parts calcium nitrate, 4 parts magnesium sulfate, and 220 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 6 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:5. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 18kHz and the ultrasonic power is 350W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0035] S3. Place the biomass char powder in a zirconia ball mill and ball mill it at 100 rpm for 2 hours to remove the composite nutrient solution loaded on the outer surface of the biomass char powder and expose the char layer.

[0036] S4. The biomass char powder is subjected to a heat treatment process of heating, holding and cooling to shrink the pores of the biomass char powder; wherein the heating rate is 3℃ / min, the holding temperature is 500℃, the holding time is 300min, the cooling rate is 0.5℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 13:1.

[0037] S5. Take biochar powder, control its humidity at 8% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (take 4±0.2mm granules) and dry to obtain the bio-cultivation substrate.

[0038] Example 2: A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0039] S1. Take the coconut shell powder after removing impurities and drying, first carbonize it in a carbonization furnace at 600℃ for 1.5h, and then activate it in an activation furnace at 850℃ for 9h to obtain biomass char powder.

[0040] S2. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 40 parts potassium sulfate, 3 parts potassium chloride, 15 parts calcium phosphate, 20 parts calcium sulfate, 18 parts calcium nitrate, 6 parts magnesium sulfate, and 250 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 9 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:6. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 22kHz and the ultrasonic power is 380W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0041] S3. Place the biomass char powder in a zirconia ball mill and ball mill it at 120 rpm for 1.5 hours to remove the composite nutrient solution loaded on the outer surface of the biomass char powder and expose the char layer.

[0042] S4. The biomass char powder is subjected to a heat treatment process of heating, holding and cooling to shrink the pores of the biomass char powder; wherein the heating rate is 5℃ / min, the holding temperature is 550℃, the holding time is 150min, the cooling rate is 1℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 13:1.

[0043] S5. Take biochar powder, control its humidity at 10% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (take 4±0.2mm granules) and dry to obtain the bio-cultivation substrate.

[0044] Example 3: A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0045] S1. Take the rice husk powder after removing impurities and drying, carbonize it in a carbonization furnace at 650℃ for 1 hour, and then activate it in an activation furnace at 900℃ for 6 hours to obtain biomass char powder.

[0046] S2. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 45 parts potassium sulfate, 5 parts potassium chloride, 20 parts calcium phosphate, 25 parts calcium sulfate, 20 parts calcium nitrate, 8 parts magnesium sulfate, and 280 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 12 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:8. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 25kHz and the ultrasonic power is 400W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0047] S3. Place the biomass char powder in a zirconia ball mill and ball mill it at 150 rpm for 1 hour to remove the composite nutrient solution loaded on the outer surface of the biomass char powder and expose the char layer.

[0048] S4. The biomass char powder is subjected to a heat treatment process of heating, holding and cooling to shrink the pores of the biomass char powder; wherein the heating rate is 8℃ / min, the holding temperature is 600℃, the holding time is 60min, the cooling rate is 2℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 13:1.

[0049] S5. Take biochar powder, control its humidity at 12% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (take 4±0.2mm granules) and dry to obtain the bio-cultivation substrate.

[0050] Examples 4-7

[0051] Based on Example 2, the volume ratio of nitrogen to oxygen in step S4 was adjusted, while keeping other step parameters unchanged, to further obtain the following examples:

[0052] Table 1: Volume ratio of nitrogen to oxygen in Examples 4-7

[0053]

[0054] Comparative Example 1

[0055] A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0056] S1. Take the coconut shell powder after removing impurities and drying, first carbonize it in a carbonization furnace at 600℃ for 1.5h, and then activate it in an activation furnace at 850℃ for 9h to obtain biomass char powder.

[0057] S2. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 40 parts potassium sulfate, 3 parts potassium chloride, 15 parts calcium phosphate, 20 parts calcium sulfate, 18 parts calcium nitrate, 6 parts magnesium sulfate, and 250 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 9 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:6. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 22kHz and the ultrasonic power is 380W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0058] S3. The biomass char powder is subjected to a heat treatment process of heating, holding and cooling to shrink the pores of the biomass char powder; wherein the heating rate is 5℃ / min, the holding temperature is 550℃, the holding time is 150min, the cooling rate is 1℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 13:1.

[0059] S4. Take biochar powder, control its humidity at 10% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (take 4±0.2mm granules) and dry to obtain the bio-cultivation substrate.

[0060] Comparative Example 2

[0061] A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0062] S1. Take the coconut shell powder after removing impurities and drying, first carbonize it in a carbonization furnace at 600℃ for 1.5h, and then activate it in an activation furnace at 850℃ for 9h to obtain biomass char powder.

[0063] S2. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 40 parts potassium sulfate, 3 parts potassium chloride, 15 parts calcium phosphate, 20 parts calcium sulfate, 18 parts calcium nitrate, 6 parts magnesium sulfate, and 250 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 9 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:6. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 22kHz and the ultrasonic power is 380W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0064] S3. Place the biomass char powder in a zirconia ball mill and ball mill it at 120 rpm for 1.5 hours to remove the composite nutrient solution loaded on the outer surface of the biomass char powder and expose the char layer.

[0065] S4. Take biochar powder, control its humidity at 10% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (take 4±0.2mm granules) and dry to obtain the bio-cultivation substrate.

[0066] Comparative Example 3

[0067] A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0068] S1. Take the coconut shell powder after removing impurities and drying, first carbonize it in a carbonization furnace at 600℃ for 1.5h, and then activate it in an activation furnace at 850℃ for 9h to obtain biomass char powder.

[0069] S2. The biomass char powder is subjected to a heat treatment process of heating, holding and cooling to shrink the pores of the biomass char powder; wherein the heating rate is 5℃ / min, the holding temperature is 550℃, the holding time is 150min, the cooling rate is 1℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 13:1.

[0070] S3. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 40 parts potassium sulfate, 3 parts potassium chloride, 15 parts calcium phosphate, 20 parts calcium sulfate, 18 parts calcium nitrate, 6 parts magnesium sulfate, and 250 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 9 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:6. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 22kHz and the ultrasonic power is 380W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0071] S4. After drying the biomass carbon powder, place it in a zirconia ball mill and ball mill it at 120 rpm for 1.5 hours to remove the composite nutrient solution loaded on the outer surface of the biomass carbon powder and expose the carbon layer.

[0072] S5. Take biochar powder, control its humidity at 10% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (take 4±0.2mm granules) and dry to obtain the bio-cultivation substrate.

[0073] Comparative Example 4

[0074] A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0075] S1. Take the coconut shell powder after removing impurities and drying, first carbonize it in a carbonization furnace at 600℃ for 1.5h, and then activate it in an activation furnace at 850℃ for 9h to obtain biomass char powder.

[0076] S2. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 40 parts potassium sulfate, 3 parts potassium chloride, 15 parts calcium phosphate, 20 parts calcium sulfate, 18 parts calcium nitrate, 6 parts magnesium sulfate, and 250 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 9 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:6. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 22kHz and the ultrasonic power is 380W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0077] S3. Place the biomass char powder in a zirconia ball mill and ball mill it at 120 rpm for 1.5 hours to remove the composite nutrient solution loaded on the outer surface of the biomass char powder and expose the char layer.

[0078] S4. The biomass char powder is subjected to a heat treatment process of heating, holding and cooling to shrink the pores of the biomass char powder; wherein the heating rate is 5℃ / min, the holding temperature is 700℃, the holding time is 150min, the cooling rate is 1℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 13:1.

[0079] S5. Take biochar powder, control its humidity at 10% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (take 4±0.2mm granules) and dry to obtain the bio-cultivation substrate.

[0080] Comparative Example 5

[0081] A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0082] S1. Take the coconut shell powder after removing impurities and drying, first carbonize it in a carbonization furnace at 600℃ for 1.5h, and then activate it in an activation furnace at 850℃ for 9h to obtain biomass char powder.

[0083] S2. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 40 parts potassium sulfate, 3 parts potassium chloride, 15 parts calcium phosphate, 20 parts calcium sulfate, 18 parts calcium nitrate, 6 parts magnesium sulfate, and 250 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 9 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:6. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 22kHz and the ultrasonic power is 380W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0084] S3. Place the biomass char powder in a zirconia ball mill and ball mill it at 120 rpm for 1.5 hours to remove the composite nutrient solution loaded on the outer surface of the biomass char powder and expose the char layer.

[0085] S4. The biomass char powder is subjected to a heat treatment process of heating, holding and cooling to shrink the pores of the biomass char powder; wherein the heating rate is 5℃ / min, the holding temperature is 800℃, the holding time is 150min, the cooling rate is 1℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 13:1.

[0086] S5. Take biochar powder, control its humidity at 10% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (take 4±0.2mm granules) and dry to obtain the bio-cultivation substrate.

[0087] Example 8

[0088] A method for preparing a nutrient-rich bio-cultivation substrate, comprising the following steps:

[0089] S1. Take the coconut shell powder after removing impurities and drying, first carbonize it in a carbonization furnace at 600℃ for 1.5h, and then activate it in an activation furnace at 850℃ for 9h to obtain biomass char powder.

[0090] S2. Prepare a compound nutrient solution. The raw materials for preparing the compound nutrient solution include 40 parts potassium sulfate, 3 parts potassium chloride, 15 parts calcium phosphate, 20 parts calcium sulfate, 18 parts calcium nitrate, 6 parts magnesium sulfate, and 250 parts water by weight. After thorough stirring, take biomass carbon powder and soak it in the compound nutrient solution for 9 hours. The weight ratio of biomass carbon powder to compound nutrient solution is 1:6. During the soaking process, apply ultrasonic vibration treatment to the compound nutrient solution. The ultrasonic frequency is 22kHz and the ultrasonic power is 380W. After soaking, take the biomass carbon powder and dry it so that the compound nutrient solution is loaded on the outer surface and pores of the biomass carbon powder.

[0091] S3. Place the biomass char powder in a zirconia ball mill and ball mill it at 120 rpm for 1.5 hours to remove the composite nutrient solution loaded on the outer surface of the biomass char powder and expose the char layer.

[0092] S4. The biomass char powder is subjected to a heat treatment process of heating, holding and cooling to shrink the pores of the biomass char powder; wherein the heating rate is 5℃ / min, the holding temperature is 550℃, the holding time is 150min, the cooling rate is 1℃ / min, and the entire heat treatment process is carried out in a combined atmosphere of nitrogen and oxygen, with a nitrogen to oxygen volume ratio of 13:1.

[0093] S5. Take biochar powder, control its humidity at 10% by spraying, then press the biochar powder into granules by a pelletizer, and finally sieve (the granules consist of two sizes: large granules of 6±0.2mm and small granules of 2±0.2mm, with a weight ratio of 3:2 between the large and small granules) and dry to obtain the bio-cultivation substrate.

[0094] III. Pore Structure Testing

[0095] The biochar powder samples obtained in Examples 1-7 and Comparative Examples 1-5 (i.e., before the granulation step) were tested for specific surface area and pore structure using nitrogen isothermal (77K) adsorption. The test results are shown in Table 2 below:

[0096] Table 2: Specific surface area and pore structure results of biomass charcoal powder samples

[0097]

[0098] As can be seen from Table 2, the biomass charcoal powder samples prepared in Examples 1-3 of the present invention have relatively stable specific surface area and total pore volume, and both are relatively small. The reason for this is that before heat treatment, there are many and large pores, and a large amount of nutrients are loaded by the charcoal powder pores. After heat treatment, the pores shrink, which compresses the remaining space in the original pores (formed by the evaporation of water from the nutrient solution), resulting in a decrease in specific surface area and total pore volume.

[0099] Examples 4-7 and Comparative Examples 1-5 were all adjustments made based on Example 2. Specifically: Examples 4-7 changed the volume ratio of nitrogen to oxygen; as the oxygen content decreased, the specific surface area and total pore volume of the biochar powder gradually increased because oxide deposition decreased; Comparative Example 1 did not undergo mechanical grinding before heat treatment, i.e., the composite nutrient solution loaded on the outer surface of the biochar powder was not removed, resulting in the char layer surface being coated with nutrients, which to some extent hindered the oxidation reaction and may have affected the expansion and contraction of the char powder, ultimately leading to a poorer pore shrinkage effect and a significant increase in specific surface area and total pore volume; Comparative Examples... 2. Without the heating-holding-cooling heat treatment process, the specific surface area and total pore volume reached their maximum. Comparative Example 3 adjusted the process, first performing heat treatment, then loading with nutrient solution and mechanical grinding. This caused the pores of the biochar powder to shrink first, resulting in a poorer loading effect. Furthermore, the space formed by the evaporation of moisture from the nutrient solution was retained after loading, leading to a larger specific surface area and total pore volume. Comparative Examples 4 and 5 adjusted the heat treatment holding temperature to 700℃ and 800℃, respectively. As the heat treatment temperature gradually increased, the specific surface area and total pore volume gradually increased. This was because the excessively high temperature caused some nutrients to decompose, exposing more pore space.

[0100] IV. Plant Cultivation Test

[0101] An indoor cultivation greenhouse was constructed, and the temperature inside the greenhouse was controlled at 25±1℃ and the humidity at 65±5%. African violet seedlings with basically the same appearance were purchased from the market. Based on the pot cultivation method, the biological cultivation substrate samples prepared by Examples 1-8 and Comparative Examples 1-5 were used for cultivation, with 5 pots set up for each group of samples.

[0102] Ten days after potting, when the African violet seedlings began to turn green again, the plant height (branch length), crown width, and number of leaves of each sample plant were measured (the average of 5 pots was calculated, rounded to one decimal place). A second measurement was taken 40 days after potting. The difference between the two measurements was used to calculate the monthly growth of the African violet seedlings. The calculation results are shown in [link to calculation]. Figure 1-3 ,in: Figure 1 This is a graph showing the results of plant height growth of African violet seedlings. Figure 2 This is a graph showing the results of crown growth in African violet seedlings. Figure 3 This is a graph showing the leaf number growth of African violet seedlings.

[0103] from Figure 1-3It can be seen that cultivation using the bio-cultivation substrate samples prepared in Examples 1-3 of this invention resulted in excellent growth of African violets in terms of plant height, crown width, and number of leaves. Examples 4-8 and Comparative Examples 1-5 were adjustments made based on Example 2. Specifically: Examples 4-7 changed the nitrogen-to-oxygen volume ratio, resulting in better overall growth. Furthermore, within a ratio range of 10-15:1, growth initially increased and then decreased with decreasing oxygen content, indicating that neither higher nor lower oxygen content is always better, exceeding pre-experimental expectations. Comparative Example 1 did not undergo mechanical grinding before heat treatment, resulting in significantly worse growth compared to Example 2. Comparative Example 2 did not undergo a heating-holding-cooling heat treatment process, resulting in relatively lower growth. Compared to Example 2, the growth was significantly worse and the worst among all groups. Comparative Example 3 adjusted the process, first performing heat treatment, then loading nutrient solution and mechanical grinding, and the growth was also significantly worse than that of Example 2. Comparative Examples 4 and 5 adjusted the heat treatment holding temperature to 700℃ and 800℃ respectively. As the heat treatment temperature gradually increased, the growth became worse and worse. In the final granulation process of Example 8, the granules were composed of two sizes: large granules of 6±0.2mm and small granules of 2±0.2mm, and the weight ratio between large and small granules was 3:2, which made the growth optimal.

[0104] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method of preparing a nutrient-rich bioculture substrate, characterized by the steps of The application relates to a preparation method of a biological cultivation substrate. S1, biomass raw materials after impurity removal and drying are processed to obtain biomass charcoal powder; S2, a composite nutrient solution is prepared, the biomass charcoal powder is soaked in the composite nutrient solution, after soaking, the biomass charcoal powder is dried to load the composite nutrient solution on the outer surface and pores of the biomass charcoal powder; According to the weight parts, the preparation raw materials of the composite nutrient solution include 35-45 parts of potassium sulfate, 2-5 parts of potassium chloride, 10-20 parts of calcium phosphate, 15-25 parts of calcium sulfate, 16-20 parts of calcium nitrate, 4-8 parts of magnesium sulfate and 220-280 parts of water; S3, the biomass charcoal powder is mechanically ground to peel off the composite nutrient solution loaded on the outer surface of the biomass charcoal powder and expose the carbon layer; S4, the biomass charcoal powder is subjected to a heat treatment process of heating-keeping warm-cooling to shrink the pores of the biomass charcoal powder; The heating rate is 3-8 DEG C / min, the keeping warm temperature is 500-600 DEG C, the keeping warm duration is 60-300 min, the cooling rate is 0.5-2 DEG C / min, and the whole heat treatment process is carried out in a composite atmosphere of nitrogen and oxygen, the volume ratio of nitrogen to oxygen is 10-15:1; S5, the biomass charcoal powder is taken to be made into particles with a set size, and the biological cultivation substrate is obtained.

2. The method for preparing a nutrient-rich biological cultivation substrate according to claim 1, characterized in that, In step S1, the biomass raw materials are selected from one of bamboo, coconut shell, rice husk and straw.

3. The method for preparing a nutrient-rich biological cultivation substrate according to claim 1, characterized in that, In step S1, the processing treatment means that the biomass is carbonized at 550-650 DEG C for 1-2 h in a carbonization furnace, and then activated at 800-900 DEG C for 6-15 h in an activation furnace.

4. The method of claim 1, wherein the nutrient-rich bio-cultivation substrate is prepared by mixing the organic material and the inorganic material in a ratio of 1:1 to 1:

3. 5 In step S2, the biomass charcoal powder is soaked in the composite nutrient solution for 6-12 h, the weight ratio of the biomass charcoal powder to the composite nutrient solution is 1:5-8, and ultrasonic oscillation treatment is applied to the composite nutrient solution during the soaking process, the ultrasonic frequency is 18-25 kHz, and the ultrasonic power is 350-400 W.

5. The method of claim 1, wherein the nutrient-rich bio-cultivation substrate is prepared by mixing the organic material and the inorganic material in a ratio of 1:1 to 1:

3. 5 In step S3, the mechanical grinding means that the biomass charcoal powder is placed in a zirconium oxide ball mill and ball milled at a speed of 100-150 rpm for 1-2 h.

6. The method of claim 1, wherein the nutrient-rich bio-cultivation substrate is prepared by mixing the organic material and the inorganic material in a ratio of 1:1 to 1:

3. 6 In step S4, the volume ratio of nitrogen to oxygen is 13:

1.

7. The method for preparing a nutrient-rich biological cultivation substrate according to claim 1, characterized in that, In step S5, the particles with a set size means that the biomass charcoal powder is taken, the humidity is controlled to be 8-12% through a spraying mode, the biomass charcoal powder is pressed into particles through a pelletizer, and finally, the particles are screened and dried.

8. A method of preparing a nutrient-rich bioculture substrate according to claim 7, characterized in that, In step S5, the particles are composed of two sizes: 6+ / -0.2mm large particles and 2+ / -0.2mm small particles, and the weight ratio between the large particles and the small particles is 3:2.

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