Preparation method of nutrient-rich biological culture medium

Abstract

The invention discloses a preparation method of a nutrient-rich biological culture medium, which comprises the following steps: taking a biomass raw material, and processing to obtain biomass charcoal powder; preparing a composite nutrient solution, soaking biomass carbon powder in the composite nutrient solution, and drying the biomass carbon powder after soaking; carrying out mechanical grinding on the biomass carbon powder; the biomass charcoal powder is subjected to a heating-heat preservation-cooling heat treatment process, so that pores of the biomass charcoal powder are shrunk; the method comprises the following steps: preparing biomass charcoal powder into particles with set sizes; according to the invention, biomass charcoal powder is taken as a carrier, and a specific combined process of nutrient solution loading, mechanical grinding and heat treatment is adopted, so that nutrients are firstly fully loaded by charcoal powder pores, and the pores are shrunk after heat treatment, so that the nutrient precipitation rate is reduced, the nutrient retention capability is improved, and the release is balanced; and soilless culture management of plants is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soilless culture, in particular to a preparation method of a nutrient-rich biological cultivation substrate. BACKGROUND

[0002] Soilless culture is an efficient, environmentally friendly and cost-saving agricultural production method, which has broad application prospects and development potential. The main types of soilless culture include water culture, air culture and substrate culture. Among them, substrate culture is a planting method in which the roots of crops are fixed in organic or inorganic substrates, and nutrient solution is supplied to crops through drip irrigation or fine flow irrigation, which has the advantages of high air permeability, water and fertilizer saving, cleanliness and no pollution.

[0003] The traditional substrate for substrate culture is mainly a mixture of inorganic substrates such as sand, gravel, rock wool, perlite and vermiculite, and organic substrates such as tree bark, bagasse, rice chaff, peat, rice chaff carbon and sawdust. The main source of nutrients is organic matter, which is very limited, so it is necessary to irrigate nutrient solution to supply the required nutrients to plants during cultivation, which will inevitably increase labor costs. With the continuous development of soilless culture technology, more and more new types of cultivation substrates have been developed and applied, such as substrates made from agricultural waste (such as mushroom mud, chicken manure, pig manure, etc.) as the main raw material through retting and fermentation. The nutrients are sufficient, but this type of substrate loses its original advantages such as air permeability, and the nutrients are released quickly and unevenly, which is not conducive to the growth of plants. SUMMARY

[0004] The present application aims to provide a preparation method of a nutrient-rich biological cultivation substrate, which solves the problems of limited nutrients in traditional cultivation substrates and poor air permeability, fast and uneven nutrient release of new agricultural waste fermentation substrates.

[0005] The present application achieves the above-mentioned purpose through the following technical solutions: A preparation method of a nutrient-rich biological cultivation substrate, comprising the following steps: S1, taking the dried biomass raw material after impurity removal, and obtaining biomass charcoal powder through processing; S2, preparing a composite nutrient solution, soaking the biomass charcoal powder in the composite nutrient solution, and drying the biomass charcoal powder after soaking to load the composite nutrient solution on the outer surface and pores of the biomass charcoal powder; According to weight parts, the preparation raw materials of the composite nutrient solution include potassium sulfate 35-45 parts, potassium chloride 2-5 parts, calcium phosphate 10-20 parts, calcium sulfate 15-25 parts, calcium nitrate 16-20 parts, magnesium sulfate 4-8 parts, and water 220-280 parts; S3, mechanically grinding the biomass carbon powder to peel off the composite nutrient solution loaded on the outer surface of the biomass carbon powder and expose the carbon layer; S4, performing a heat treatment process of heating-keeping warm-cooling on the biomass carbon powder to make the pores of the biomass carbon powder shrink; Wherein, the heating rate is 3-8℃ / min, the keeping warm temperature is 500-600℃, the keeping warm time length is 60-300min, the cooling rate is 0.5-2℃ / 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, taking the biomass carbon powder to make particles of a set size, thereby obtaining the biological cultivation substrate.

[0006] Further improvement lies in that in step S1, the biomass raw material is selected from one of bamboo, coconut shell, rice husk or straw.

[0007] Further improvement lies in that in step S1, the processing treatment refers to carbonization at 550-650℃ for 1-2h in a carbonization furnace, and then activation at 800-900℃ for 6-15h in an activation furnace.

[0008] Further improvement lies in that in step S2, the biomass carbon powder is soaked in the composite nutrient solution for 6-12h, the weight ratio of the biomass carbon 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 18-25kHz, and the ultrasonic power is 350-400W.

[0009] Further improvement lies in that in step S3, the mechanical grinding refers to placing the biomass carbon powder in a zirconium oxide ball mill and ball milling at a speed of 100-150rpm for 1-2h.

[0010] Further improvement lies in that in step S4, the volume ratio of nitrogen to oxygen is 13:1.

[0011] Further improvement lies in that in step S5, the making of particles of a set size refers to taking the biomass carbon powder, controlling its humidity at 8-12% through spraying, pressing the biomass carbon powder into particles through a pelletizer, and finally screening and drying.

[0012] Further improvement lies in that in step S5, the particles are composed of two sizes, i.e., 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.

[0013] The beneficial effects of the present application are as follows: (1) The present application takes biomass charcoal powder as a carrier, adopts a specific combined process of loading nutrient solution, mechanical grinding and heat treatment, so that the nutrients are first fully loaded in the pores of the charcoal powder, and after heat treatment, the pores shrink, the nutrient release rate is reduced, the nutrient retention capacity is improved and the release is balanced, and at the same time, the granular substrate has excellent aeration and drainage performance, which is very beneficial to the soilless cultivation management of plants.

[0014] The purpose of mechanical grinding is to peel off the composite nutrient solution loaded on the outer surface of the biomass charcoal powder and expose the carbon layer, and the grinding speed and time are small, which basically will not cause unnecessary damage to the charcoal powder; the heat treatment of heating-keeping- cooling makes the surface of the charcoal powder swell and shrink and the carbon atom bond rearrangement process, the highest temperature of the treatment is lower than 600 DEG C, which can ensure the treatment effect while not causing the decomposition of the inorganic salt nutrients, and the cooling rate is small, which reduces the generation of thermal stress and also avoids the damage of the charcoal powder; at the same time, under the atmosphere of 10-15:1 (especially 13:1) of nitrogen and oxygen, the exposed carbon layer can have a certain oxidation reaction, causing the deposition of oxides at the pore position, but not completely blocking the pores. Under the above series of comprehensive actions, the surface pores of the charcoal powder shrink, the nutrient release rate is reduced, and becomes balanced.

[0015] (2) The biological cultivation substrate of the present application adopts the compounding of two different particle sizes of particles, which can not only maintain good aeration and drainage performance, improve the nutrient retention and supply capacity of the substrate, but also enhance the structural stability, prevent the substrate from caking or hardening, and optimize the root growth environment. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the plant height growth result graph of African violet seedlings; Figure 2 is the crown width growth result graph of African violet seedlings; Figure 3 is the leaf number growth result graph of African violet seedlings. DETAILED DESCRIPTION

[0017] Hereinafter, the present application will be described in further detail with specific examples, and it is necessary to point out that the following specific embodiments are only used to further illustrate the present application, and cannot be understood as limiting the protection scope of the present application, and those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above application content.

[0018] I. Experimental instruments LHT 02 / 17 LB series carbonization furnace of Nabertherm Company, Switzerland; CWF 1200 activation furnace of Carbolite Gero; Q700 ultrasonic oscillator of Qsonica; Pulverisette 7 Premium Line ball mill of Fritsch; LHT 02 / 17 LB high temperature furnace of Nabertherm; SD-6 spray dryer of Labplant; double roller pelletizer of FEECO International Company; SY-600 vibrating screen of Sieve Technologies.

[0019] II. Experimental method Example 1 A method for preparing a nutrient-rich biological cultivation substrate, the steps comprising: S1, taking the dried bamboo-wood powder, first carbonizing in a carbonization furnace at 550℃ for 2h, and then activating in an activation furnace at 800℃ for 15h to obtain biomass charcoal powder; S2, preparing a composite nutrient solution, the preparation raw materials of the composite nutrient solution including potassium sulfate 35 parts, potassium chloride 2 parts, calcium phosphate 10 parts, calcium sulfate 15 parts, calcium nitrate 16 parts, magnesium sulfate 4 parts, and water 220 parts, according to weight fraction, after sufficient stirring, soaking the biomass charcoal powder in the composite nutrient solution for 6h, the weight ratio of biomass charcoal powder to composite nutrient solution being 1:5, and applying ultrasonic oscillation treatment to the composite nutrient solution during the soaking process, the ultrasonic frequency being 18kHz and the ultrasonic power being 350W, after soaking, taking the biomass charcoal powder to dry, so that the composite nutrient solution is loaded on the outer surface and pores of the biomass charcoal powder; S3, placing the biomass charcoal powder in a zirconium oxide ball mill, ball milling at a speed of 100rpm for 2h to strip the composite nutrient solution loaded on the outer surface of the biomass charcoal powder and expose the carbon layer; S4, performing a heat treatment process of heating-keeping warm-cooling on the biomass charcoal powder to shrink the pores of the biomass charcoal powder; wherein the heating rate is 3℃ / min, the keeping warm temperature is 500℃, the keeping warm duration is 300min, and the cooling rate is 0.5℃ / 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 being 13:1; S5, taking the biomass charcoal powder, controlling its humidity at 8% by spraying, then pressing the biomass charcoal powder into particles by a pelletizer, and finally screening (taking 4±0.2mm particles), drying, to obtain the biological cultivation substrate.

[0020] Example 2 A method for preparing a nutrient-rich biological cultivation substrate, the steps comprising: S1, after the impurity removal and drying, the coconut shell powder was carbonized at 600 DEG C for 1.5 h in a carbonization furnace, and then activated at 850 DEG C for 9 h in an activation furnace to obtain biomass charcoal powder; S2, a composite nutrient solution was prepared, and the preparation raw materials of the composite nutrient solution included, by weight fraction, potassium sulfate 40 parts, potassium chloride 3 parts, calcium phosphate 15 parts, calcium sulfate 20 parts, calcium nitrate 18 parts, magnesium sulfate 6 parts, and water 250 parts; after sufficient stirring, the biomass charcoal powder was soaked in the composite nutrient solution for 9 h, the weight ratio of the biomass charcoal powder to the composite nutrient solution was 1:6, and ultrasonic oscillation treatment was applied to the composite nutrient solution during the soaking process, the ultrasonic frequency was 22 kHz, the ultrasonic power was 380 W; after the soaking was completed, the biomass charcoal powder was dried to load the composite nutrient solution on the outer surface and pores of the biomass charcoal powder; S3, the biomass charcoal powder was placed in a zirconia ball mill and ball milled at a speed of 120 rpm for 1.5 h to strip the composite nutrient solution loaded on the outer surface of the biomass charcoal powder and expose the carbon layer; S4, the biomass charcoal powder was subjected to a heat treatment process of heating-keeping warm-cooling to shrink the pores of the biomass charcoal powder; the heating rate was 5 DEG C / min, the keeping warm temperature was 550 DEG C, the keeping warm time was 150 min, and the cooling rate was 1 DEG C / min; the whole heat treatment process was carried out in a composite atmosphere of nitrogen and oxygen, and the volume ratio of nitrogen to oxygen was 13:1; S5, the biomass charcoal powder was taken, the humidity thereof was controlled at 10% by spraying, the biomass charcoal powder was pressed into particles by a pelletizer, and finally the particles were sieved (4±0.2 mm particles were taken), and dried to obtain the biological cultivation substrate.

[0021] Embodiment 3, a preparation method of a nutrient-rich biological cultivation substrate, the steps comprising: S1, after the impurity removal and drying, the coconut shell powder was carbonized at 600 DEG C for 1.5 h in a carbonization furnace, and then activated at 850 DEG C for 9 h in an activation furnace to obtain biomass charcoal powder; S2, a composite nutrient solution was prepared, and the preparation raw materials of the composite nutrient solution included, by weight fraction, potassium sulfate 40 parts, potassium chloride 3 parts, calcium phosphate 15 parts, calcium sulfate 20 parts, calcium nitrate 18 parts, magnesium sulfate 6 parts, and water 250 parts; after sufficient stirring, the biomass charcoal powder was soaked in the composite nutrient solution for 9 h, the weight ratio of the biomass charcoal powder to the composite nutrient solution was 1:6, and ultrasonic oscillation treatment was applied to the composite nutrient solution during the soaking process, the ultrasonic frequency was 22 kHz, the ultrasonic power was 380 W; after the soaking was completed, the biomass charcoal powder was dried to load the composite nutrient solution on the outer surface and pores of the biomass charcoal powder; S3, the biomass charcoal powder was placed in a zirconia ball mill and ball milled at a speed of 120 rpm for 1.5 h to strip the composite nutrient solution loaded on the outer surface of the biomass charcoal powder and expose the carbon layer; S4, a heat treatment process of heating-keeping warm-cooling is performed on the biomass charcoal powder, so that the pores of the biomass charcoal powder shrink; wherein the heating rate is 8℃ / min, the keeping warm temperature is 600℃, the keeping warm time length is 60min, the cooling rate is 2℃ / 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 13:1; S5, taking the biomass charcoal powder, controlling its humidity at 12% by spraying, then pressing the biomass charcoal powder into particles by a pelletizer, finally screening (taking 4±0.2mm particles) and drying, thus obtaining the biological cultivation substrate.

[0022] Examples 4-7 On the basis of Example 2, adjusting the volume ratio of nitrogen to oxygen in step S4, and controlling other step parameters unchanged, the following examples are further obtained: Table 1: Volume ratio of nitrogen to oxygen in Examples 4-7

[0023] Comparative Example 1 A preparation method of a nutrient-rich biological cultivation substrate, the steps comprising: S1, taking the dried coconut shell powder after removing impurities, first carbonizing it in a carbonization furnace at 600℃ for 1.5h, then activating it in an activation furnace at 850℃ for 9h, thus obtaining biomass charcoal powder; S2, preparing a composite nutrient solution, the preparation raw materials of the composite nutrient solution include, by weight fraction, potassium sulfate 40 parts, potassium chloride 3 parts, calcium phosphate 15 parts, calcium sulfate 20 parts, calcium nitrate 18 parts, magnesium sulfate 6 parts, and water 250 parts, after fully stirring, taking the biomass charcoal powder to soak in the composite nutrient solution, the time is 9h, the weight ratio of the biomass charcoal powder to the composite nutrient solution is 1:6, and during the soaking process, ultrasonic oscillation treatment is applied to the composite nutrient solution, the ultrasonic frequency is 22kHz, the ultrasonic power is 380W, after soaking, the biomass charcoal powder is dried, so that the composite nutrient solution is loaded on the outer surface and pores of the biomass charcoal powder; S3, a heat treatment process of heating-keeping warm-cooling is performed on the biomass charcoal powder, so that the pores of the biomass charcoal powder shrink; wherein the heating rate is 8℃ / min, the keeping warm temperature is 600℃, the keeping warm time length is 60min, the cooling rate is 2℃ / 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 13:1; S4, taking the biomass charcoal powder, controlling its humidity at 12% by spraying, then pressing the biomass charcoal powder into particles by a pelletizer, finally screening (taking 4±0.2mm particles) and drying, thus obtaining the biological cultivation substrate.

[0024] Comparative Example 2 A method for preparing a nutrient-rich biological cultivation substrate, comprising the steps of: S1, taking the dried coconut shell powder, first carbonizing in the carbonization furnace at 600℃ for 1.5h, then activating in the activation furnace at 850℃ for 9h, to obtain biomass charcoal powder; S2, preparing a composite nutrient solution, according to weight fraction, the preparation raw materials of the composite nutrient solution include potassium sulfate 40 parts, potassium chloride 3 parts, calcium phosphate 15 parts, calcium sulfate 20 parts, calcium nitrate 18 parts, magnesium sulfate 6 parts, water 250 parts, after fully stirring, take the biomass carbon powder and soak in the composite nutrient solution, the time is 9h, the weight ratio of biomass carbon powder to composite nutrient solution is 1:6, and ultrasonic oscillation treatment is applied to the composite nutrient solution during the soaking process, the ultrasonic frequency is 22kHz, the ultrasonic power is 380W, after soaking, take the biomass carbon powder and dry, load the composite nutrient solution on the outer surface and pores of the biomass charcoal powder; S3, placing the biomass charcoal powder in a zirconium oxide ball mill, ball milling at a speed of 120rpm for 1.5h, to strip the composite nutrient solution loaded on the outer surface of the biomass charcoal powder and expose the carbon layer; S4, taking the biomass charcoal powder, controlling its humidity at 10% by spraying, then pressing the biomass charcoal powder into particles by a pelletizer, finally screening (taking 4±0.2mm particles), drying, to obtain the biological cultivation substrate.

[0025] Comparative Example 3 A method for preparing a nutrient-rich biological cultivation substrate, comprising the steps of: S1, taking the dried coconut shell powder, first carbonizing in the carbonization furnace at 600℃ for 1.5h, then activating in the activation furnace at 850℃ for 9h, to obtain biomass charcoal powder; S2, performing a heating-keeping-temperature-cooling heat treatment process on the biomass charcoal powder, to shrink the pores of the biomass charcoal powder; wherein the heating rate is 5℃ / min, the keeping-temperature is 550℃, the keeping-temperature duration is 150min, the cooling rate is 1℃ / 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 13:1; S3, preparing a composite nutrient solution, according to weight fraction, the preparation raw materials of the composite nutrient solution include potassium sulfate 40 parts, potassium chloride 3 parts, calcium phosphate 15 parts, calcium sulfate 20 parts, calcium nitrate 18 parts, magnesium sulfate 6 parts, water 250 parts, after fully stirring, take the biomass carbon powder and soak in the composite nutrient solution, the time is 9h, the weight ratio of biomass carbon powder to composite nutrient solution is 1:6, and ultrasonic oscillation treatment is applied to the composite nutrient solution during the soaking process, the ultrasonic frequency is 22kHz, the ultrasonic power is 380W, after soaking, take the biomass carbon powder and dry, load the composite nutrient solution on the outer surface and pores of the biomass charcoal powder; S4, after drying the biomass carbon powder, put it in a zirconium oxide ball mill, and ball mill at a speed of 120 rpm for 1.5 h to strip the composite nutrient solution loaded on the outer surface of the biomass carbon powder and expose the carbon layer; S5, take the biomass carbon powder, control its humidity at 10% by spraying, then press the biomass carbon powder into granules by a pellet press, and finally screen (take 4±0.2 mm granules) and dry to obtain the biological cultivation substrate.

[0026] Comparative Example 4 A method for preparing a nutrient-rich biological cultivation substrate, comprising the following steps: S1, take the dried coconut shell powder, first carbonize it in a carbonization furnace at 600℃ for 1.5 h, then activate it in an activation furnace at 850℃ for 9 h to obtain biomass carbon powder; S2, prepare a composite nutrient solution, the preparation raw materials of the composite nutrient solution include potassium sulfate 40 parts, potassium chloride 3 parts, calcium phosphate 15 parts, calcium sulfate 20 parts, calcium nitrate 18 parts, magnesium sulfate 6 parts, and water 250 parts by weight fraction, after sufficient stirring, soak the biomass carbon powder in the composite nutrient solution for 9 h, the weight ratio of the biomass carbon powder to the composite nutrient solution is 1:6, and ultrasonic oscillation treatment is applied to the composite nutrient solution during the soaking process, the ultrasonic frequency is 22 kHz, and the ultrasonic power is 380 W, after soaking, dry the biomass carbon powder to load the composite nutrient solution on the outer surface and pores of the biomass carbon powder; S3, put the biomass carbon powder in a zirconium oxide ball mill and ball mill at a speed of 120 rpm for 1.5 h to strip the composite nutrient solution loaded on the outer surface of the biomass carbon powder and expose the carbon layer; S4, perform a heat treatment process of heating-keeping warm-cooling on the biomass carbon powder to shrink the pores of the biomass carbon powder; wherein the heating rate is 5℃ / min, the keeping warm temperature is 700℃, the keeping warm time is 150 min, the cooling rate is 1℃ / 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 13:1; S5, take the biomass carbon powder, control its humidity at 10% by spraying, then press the biomass carbon powder into granules by a pellet press, and finally screen (take 4±0.2 mm granules) and dry to obtain the biological cultivation substrate.

[0027] Comparative Example 5 A method for preparing a nutrient-rich biological cultivation substrate, comprising the following steps: S1, take the dried coconut shell powder, first carbonize it in a carbonization furnace at 600℃ for 1.5 h, then activate it in an activation furnace at 850℃ for 9 h to obtain biomass carbon powder; S2, a composite nutrient solution is prepared, and the preparation raw materials of the composite nutrient solution include, in terms of weight fraction, potassium sulfate 40 parts, potassium chloride 3 parts, calcium phosphate 15 parts, calcium sulfate 20 parts, calcium nitrate 18 parts, magnesium sulfate 6 parts, and water 250 parts. After being fully stirred, the biomass carbon powder is soaked in the composite nutrient solution for 9 hours, the weight ratio of the biomass carbon powder to the composite nutrient solution is 1:6, and ultrasonic oscillation treatment is applied to the composite nutrient solution during the soaking process, the ultrasonic frequency is 22 kHz, and the ultrasonic power is 380 W. After the soaking is completed, the biomass carbon powder is dried, and the composite nutrient solution is loaded on the outer surface and pores of the biomass carbon powder; S3, the biomass carbon powder is placed in a zirconia ball mill, and is ball milled at a speed of 120 rpm for 1.5 hours to strip the composite nutrient solution loaded on the outer surface of the biomass carbon powder and expose the carbon layer; S4, the biomass carbon powder is subjected to a heat treatment process of heating-keeping warm-cooling to shrink the pores of the biomass carbon powder, wherein the heating rate is 5 ℃ / min, the keeping warm temperature is 800 ℃, the keeping warm duration is 150 min, and the cooling rate is 1 ℃ / min, and the entire heat treatment process is performed in a composite atmosphere of nitrogen and oxygen, and the volume ratio of nitrogen to oxygen is 13:1; S5, the biomass carbon powder is taken, the humidity thereof is controlled to be 10% through spraying, the biomass carbon powder is pressed into particles through a pelletizer, and finally, the biomass carbon powder is screened (4±0.2 mm particles are taken), and dried, thereby obtaining the biological cultivation substrate.

[0028] Example 8 A preparation method of a nutrient-rich biological cultivation substrate, comprising the following steps: S1, taking the dried coconut shell powder, first carbonizing it in a carbonization furnace at 600 ℃ for 1.5 hours, and then activating it in an activation furnace at 850 ℃ for 9 hours to obtain biomass carbon powder; S2, a composite nutrient solution is prepared, and the preparation raw materials of the composite nutrient solution include, in terms of weight fraction, potassium sulfate 40 parts, potassium chloride 3 parts, calcium phosphate 15 parts, calcium sulfate 20 parts, calcium nitrate 18 parts, magnesium sulfate 6 parts, and water 250 parts. After being fully stirred, the biomass carbon powder is soaked in the composite nutrient solution for 9 hours, the weight ratio of the biomass carbon powder to the composite nutrient solution is 1:6, and ultrasonic oscillation treatment is applied to the composite nutrient solution during the soaking process, the ultrasonic frequency is 22 kHz, and the ultrasonic power is 380 W. After the soaking is completed, the biomass carbon powder is dried, and the composite nutrient solution is loaded on the outer surface and pores of the biomass carbon powder; S3, the biomass carbon powder is placed in a zirconia ball mill, and is ball milled at a speed of 120 rpm for 1.5 hours to strip the composite nutrient solution loaded on the outer surface of the biomass carbon powder and expose the carbon layer; S4, the biomass charcoal powder is subjected to a heat treatment process of heating-keeping warm-cooling to make the pores of the biomass charcoal powder shrink; wherein the heating rate is 5℃ / min, the keeping warm temperature is 550℃, the keeping warm time is 150min, the cooling rate is 1℃ / 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 13:1; S5, the biomass charcoal powder is taken, the humidity thereof is controlled to be 10% by spraying, then the biomass charcoal powder is pressed into particles by a granulator, finally the particles are screened (the particles taken are composed 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), and dried, thereby obtaining the biological cultivation substrate.

[0029] III. Pore structure test The biomass charcoal powder samples (i.e. before the granulation step) finally obtained from the above examples 1-7 and comparative examples 1-5 are subjected to nitrogen isothermal (77K) adsorption method to test the specific surface area and pore structure of the biomass charcoal powder samples, and the test results are shown in the following table 2: Table 2: Specific surface area and pore structure results of biomass charcoal powder samples

[0030] As can be seen from table 2, the specific surface area and total pore volume of the biomass charcoal powder samples prepared by examples 1-3 of the present application are relatively stable and relatively small, and the reason is that: before heat treatment, the pores are more and larger, and a large amount of nutrients are loaded in the pores of the charcoal powder, and after heat treatment, the pores shrink, so that the space (formed by the evaporation of nutrient solution water) originally remaining in the pores is compressed, resulting in the decrease of the specific surface area and total pore volume.

[0031] Examples 4-7 and Comparative Examples 1-5 are all made on the basis of adjusting Example 2, wherein: Examples 4-7 change the volume ratio of nitrogen to oxygen, and as the oxygen content decreases, the specific surface area and total pore volume of the biomass charcoal powder gradually increase, because the oxide deposition is less; Comparative Example 1 does not perform the step of mechanical grinding before heat treatment, i.e., does not strip the biomass charcoal powder of the outer surface load of the complex nutrient solution, so that the carbon layer surface is coated with nutrient substances, to some extent hindering the oxidation reaction, and possibly having some impact on the expansion and contraction of the charcoal powder, ultimately making the pore shrinkage effect worse, and the specific surface area and total pore volume significantly increase; Comparative Example 2 does not perform the heat treatment process of heating-keeping warm-cooling, and the specific surface area and total pore volume reach the maximum; Comparative Example 3 adjusts the process, which first performs heat treatment, and then loads the nutrient solution and mechanically grinds, which makes the pores of the biomass charcoal powder shrink first, and the subsequent loading effect is poor, and after loading, the space formed by the volatilization of the nutrient solution water is retained, resulting in a larger specific surface area and total pore volume; Comparative Examples 4 and 5 adjust the keeping warm temperature of the heat treatment to 700°C and 800°C, respectively, and as the heat treatment temperature gradually increases, it is found that the specific surface area and total pore volume gradually increase, because the decomposition of part of the nutrients exposes more pore space due to the excessively high temperature.

[0032] IV. Plant Cultivation Test An indoor cultivation greenhouse is built, the temperature in the greenhouse is controlled to be 25±1°C, and the humidity is controlled to be 65±5%. Market-purchased African violet seedlings with basically the same apparent shape are used for cultivation based on the potting method, and the biological cultivation substrates samples prepared in Examples 1-8 and Comparative Examples 1-5 are used for cultivation, respectively, and 5 pots are set for each sample.

[0033] When the African violet seedlings turn green 10 days after being potted, the plant height (branch length), crown width and leaf number of each sample are measured (the average value of 5 pots is taken, and the first decimal place is retained), and the measurement is performed again 40 days after being potted, the monthly growth amount of the African violet seedlings is calculated by the difference between the two measurements, and the calculation results are shown in Table 1. Figures 1-3 Figure 1 is a plant height growth result graph of the African violet seedlings, Figure 2 is a crown width growth result graph of the African violet seedlings, Figure 3 is a leaf number growth result graph of the African violet seedlings.

[0034] From the above results, it can be seen that the biomass charcoal powder prepared in Example 2 has the best performance in the plant cultivation test, and the biomass charcoal powder prepared in Comparative Example 1 has the worst performance in the plant cultivation test. Figures 1-3 ​It can be seen that the biological cultivation substrate samples prepared by the embodiments 1-3 of the present application are used for cultivation, so that the African violet performs well in plant height, crown width and leaf number, and the growth amount is excellent. The embodiments 4-8 and the comparative examples 1-5 are all adjustments based on the embodiment 2, wherein: the embodiments 4-7 change the volume ratio of nitrogen and oxygen, and the overall growth amount is relatively good, and in the range of 10-15:1, with the decrease of oxygen content, the growth amount shows a trend of first increasing and then decreasing, which shows that the oxygen content is not the higher the better, and also not the lower the better, which exceeds the expectation before the experiment; the comparative example 1 does not perform the mechanical grinding step before the heat treatment, and the growth amount is obviously worse than that of the embodiment 2; the comparative example 2 does not perform the heat treatment process of heating-keeping warm-cooling, and the growth amount is also obviously worse than that of the embodiment 2, and is the worst in all groups; the comparative example 3 adjusts the process, which first performs the heat treatment, then loads the nutrient solution and mechanically grinds, and the growth amount is also obviously worse than that of the embodiment 2; the comparative example 4 and the comparative example 5 adjust the keeping warm temperature of the heat treatment to 700 DEG C and 800 DEG C respectively, and with the gradual increase of the heat treatment temperature, the growth amount becomes worse and worse; the embodiment 8 in the final granulation process, the particles taken 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, which makes the growth amount optimal.

[0035] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as the limitation of the scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application.

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, biomass charcoal powder is soaked in the composite nutrient solution, after soaking, the biomass charcoal powder is dried, and the composite nutrient solution is loaded on the outer surface and pores of the biomass charcoal powder; According to 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 of a set size, and the biological cultivation substrate is obtained.

2. The method for preparing a nutrient-rich biological cultivation matrix 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 matrix 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 matrix according to claim 1, characterized in that: In step S5, the particles of a set size means that the biomass charcoal powder is taken, the humidity of the biomass charcoal powder 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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