Bamboo fiber matrix for soilless culture and preparation method and application thereof

Abstract

The invention relates to the technical field of agricultural cultivation, and particularly discloses a bamboo fiber matrix for soilless culture and a preparation method and application thereof. The preparation method comprises the following steps: raw material treatment: crushing bamboos, and screening to obtain bamboo particles of 5-10 meshes; and modification treatment: placing the bamboo particles in a conventional carbonization furnace, and carrying out low-temperature dry distillation calcination in an anoxic environment to prepare the bamboo fiber matrix. The bamboo fiber matrix prepared by the method has the core characteristics of high porosity, high specific surface area, corrosion resistance, durability, sterility and stable physicochemical properties, and soil-borne diseases can be prevented from occurring from the source. The method is especially suitable for soilless potting of commercial crops such as blueberries and tomatoes in plastic greenhouses. The production and application process of the soilless culture substrate is greatly simplified, the cost is remarkably reduced, the raw materials are fast-growing renewable bamboos, the process is green and environmentally friendly, and a high-performance, low-cost and sustainable single substrate solution is provided for the field of soilless culture.

Description

Technical Field

[0001] This invention relates to the field of agricultural cultivation technology, and in particular to a bamboo fiber substrate for soilless cultivation, its preparation method, and its application. Background Technology

[0002] Soilless cultivation, as one of the core technologies of modern agriculture, aims to provide a stable support for plant roots through a cultivation substrate and to create a suitable environment for water, air, and fertilizer, directly affecting crop growth, yield, and quality. Currently, because a single material cannot simultaneously meet multiple requirements such as water retention, aeration, root stabilization, and nutrient buffering, the industry generally adopts a compound model of "organic substrate + inorganic substrate" to prepare cultivation substrates. Existing compound substrates commonly used components have many inherent drawbacks: In organic substrates, coconut coir is largely imported, resulting in high transportation costs, and the salt content of natural coconut coir requires additional desalination treatment, increasing process complexity; peat, as a non-renewable natural resource, severely damages wetland ecosystems during extraction, contradicting the concept of green agriculture. In inorganic substrates, while perlite and vermiculite provide aeration and drainage, they lack nutrient supply capacity and have poor buffering properties. Furthermore, vermiculite's structure is prone to collapse after long-term use, and the dust generated during perlite processing and use can adversely affect the environment and human health. Based on the aforementioned component characteristics, producers need to precisely measure and uniformly mix organic and inorganic substrates in a specific ratio (e.g., coconut coir: perlite = 7:3) to simulate the granular structure of ideal soil. This model has significant technical challenges: First, the formula and process are complex, requiring additional metering and mixing equipment, increasing production steps and labor costs; second, the overall cost is high, with the procurement of various raw materials, long-distance transportation, and compound processing leading to persistently high prices for the final substrate; third, the quality stability is poor, with significant differences in the performance of raw materials from different origins and batches, easily leading to fluctuations in the performance of the compound substrate and affecting the consistency of cultivation results; fourth, the risk of pests and diseases is high, as incomplete disinfection of the organic substrate can easily carry pathogens and insect eggs, becoming a source of soil-borne diseases; fifth, there is significant pressure on resources and the environment, with dependence on peat exacerbating the risk of resource depletion and dependence on imported coconut coir reducing industrial autonomy. Therefore, developing a single-type soilless cultivation substrate that integrates multiple functions, has stable performance, is environmentally friendly, and has low cost to replace traditional compound substrates has become a key need to solve the current pain points in the industry. Summary of the Invention

[0003] This invention aims to overcome the shortcomings of existing soilless cultivation compound substrates, such as complex processes, high costs, resource dependence, and unstable quality. It provides a bamboo fiber substrate for soilless cultivation, its preparation method, and its application. Through a specific process, bamboo is transformed into a single high-performance cultivation substrate, achieving a complete replacement of traditional compound substrates and promoting the development of soilless cultivation technology towards green, efficient, and low-cost directions. To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a bamboo fiber substrate for hydroponics, comprising the following steps: S1. Raw material processing: Bamboo is selected as the raw material, and after crushing, bamboo particles with a particle size of 5 to 10 mesh are collected by sieving. S2. Modification treatment: The bamboo particles obtained in step S1 are placed in a conventional carbonization furnace and subjected to low-temperature dry distillation and calcination under oxygen-deficient conditions. After cooling, the bamboo fiber matrix is ​​obtained. Furthermore, in step S2, the temperature of the low-temperature dry distillation calcination is 300℃~600℃. Furthermore, the temperature for the low-temperature dry distillation and calcination is 400℃~500℃. Furthermore, in step S2, the oxygen-deficient conditions are achieved through the closed structure of a conventional carbonization furnace. During the dry distillation process, the bamboo particles consume oxygen in the furnace and generate combustible gas, thus creating a self-generated oxygen-deficient environment. Furthermore, in step S2, the dry distillation and calcination time is 1 to 3 hours. Secondly, the present invention provides a bamboo fiber matrix prepared by the above-described preparation method. Furthermore, the porosity of the bamboo fiber matrix is ​​60%–85%, and the specific surface area is ≥200 m² / g. Furthermore, the pH value of the bamboo fiber matrix is ​​6.5 to 8.0. Thirdly, the present invention provides the application of the above-mentioned bamboo fiber substrate as a plant cultivation substrate. Furthermore, the bamboo fiber substrate can be used directly as a single cultivation substrate to replace the traditional mixed cultivation substrate composed of two or more materials selected from coconut coir, peat, perlite, and vermiculite. The beneficial effects of this invention are as follows: 1. Elimination of key elements, revolutionizing traditional processes: The core innovation of this invention lies in eliminating the compounding process of traditional substrates. A single bamboo fiber substrate can simultaneously meet multiple needs such as water retention, aeration, root strengthening, and disease prevention, coordinating and resolving the contradiction between water and air. The cultivation effect reaches or even exceeds that of traditional compound substrates, greatly simplifying the entire chain of substrate production, transportation, and application, and reducing the operational complexity in the production and cultivation process. 2. Superior performance and excellent cultivation results: Through the core process of anaerobic dry distillation, bamboo fiber is transformed into biochar-based material, forming a stable three-dimensional porous structure. The high porosity and high specific surface area endow it with excellent water retention, air permeability and nutrient adsorption capacity, which can create a suitable growth environment for crop roots. At the same time, its physicochemical properties are stable and it is not easy to harden or collapse with long-term use, ensuring the consistency of cultivation results. 3. Sterile and disease-preventing, durable and environmentally friendly: The dry distillation and calcination process is equivalent to high-temperature sterilization, which can completely kill pathogens, insect eggs and weed seeds in bamboo, blocking the spread of soil-borne diseases from the source; the carbonized bamboo fiber has stable chemical properties, is corrosion-resistant and wear-resistant, has a long service life, can be repeatedly recycled, reduces agricultural waste, and is in line with the concept of environmental protection. 4. Simple process and significant cost advantage: Production can be achieved using a conventional carbonization furnace, without the need for expensive special equipment and inert gas protection systems. It relies on the dry distillation of bamboo to create an oxygen-deficient environment, resulting in low equipment investment and operating costs. The raw material is fast-growing bamboo, which is widely available and inexpensive. Compared with imported coconut coir and scarce peat, the raw material cost is significantly reduced, making it easy to promote large-scale industrialization. 5. Sustainable resources, in line with green agriculture: Bamboo is a fast-growing renewable resource with a short growth cycle and high yield. This invention opens up a new path for the high-value utilization of bamboo. At the same time, it replaces non-renewable peat and coconut coir, which has a high import dependence, reducing the risk of industrial resource dependence and practicing the concept of green, circular and sustainable agricultural development. Attached Figure Description To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. Figure 1 This is a flowchart of the bamboo fiber matrix preparation process of the present invention. Detailed Implementation To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. A method for preparing a bamboo fiber substrate for hydroponics, comprising the following steps: S1. Raw material processing: Select dried bamboo (such as moso bamboo, bamboo, etc.) as raw material, crush it with a wood pulverizer, and screen it with a vibrating sieve to collect bamboo particles with a particle size of 5-10 mesh, and remove impurities for later use; this particle size range can ensure uniform heat conduction in the subsequent dry distillation process, and at the same time ensure that the finished product matrix has a suitable pore structure. S2. Modification treatment: The bamboo particles obtained in step S1 are uniformly loaded into a conventional carbonization furnace (such as a continuous carbonization furnace, a brick kiln carbonization furnace, etc.), the furnace body is closed to form a closed space, and the bamboo particles are subjected to low-temperature dry distillation and calcination in an oxygen-deficient environment by controlling the heating rate and the feeding speed. After the dry distillation is completed, the material is cooled to below 80°C under closed conditions, and the bamboo fiber matrix is ​​obtained by discharging the material. The low-temperature dry distillation calcination temperature is 300℃~600℃, more preferably 400℃~500℃. Below 300℃, dry distillation is insufficient, the bamboo particles do not form a stable porous structure, and the water retention and ventilation performance is poor. Above 600℃, the bamboo particles are prone to excessive ashing, the pore structure collapses, and the specific surface area decreases. The 400℃~500℃ range allows for moderate carbonization of the bamboo fiber, forming a stable three-dimensional porous structure that balances water retention, ventilation, and structural stability. The dry distillation calcination time is 1~3 hours, which can be adjusted according to the type of carbonization furnace and the amount of bamboo particles used. Insufficient time results in incomplete pyrolysis of the bamboo particles and unstable physicochemical properties; excessive time increases energy consumption and production costs. 1~3 hours ensures uniform pyrolysis of the bamboo particles, forming a stable finished product matrix. The oxygen-deficient environment is autonomously formed by the closed structure of the carbonization furnace. During the dry distillation process, the bamboo particles themselves oxidize and consume the oxygen in the furnace, while producing combustible gases such as methane and carbon monoxide, which further inhibits the oxidation reaction. There is no need to introduce inert protective gases such as nitrogen and argon, which greatly reduces equipment investment and operating costs, making it suitable for large-scale industrial production. A bamboo fiber matrix prepared by the above method has a porosity of 60%–85%, a specific surface area ≥200 m² / g, and a pH value of 6.5–8.0. Its high porosity and high specific surface area endow it with excellent water retention, aeration, and nutrient adsorption capabilities, effectively resolving the water and air imbalances in soilless cultivation. Its neutral to slightly alkaline pH value is suitable for the growth needs of most crops, and its stable physicochemical properties mean it is not prone to structural collapse or performance degradation with long-term use. This invention provides a bamboo fiber substrate that can be used directly as a single cultivation substrate without the need for mixing with any other materials. It can completely replace the traditional mixed substrate made of two or more materials from coconut coir, peat, perlite, and vermiculite. The applicable scope covers various crops such as vegetables, flowers, and seedlings. It can be applied to various soilless cultivation scenarios such as container cultivation, trough cultivation, bag cultivation, and rooftop agriculture in facility agriculture such as plastic greenhouses and greenhouses. It is especially suitable for economic crops such as blueberries and tomatoes that have high requirements for root environment. Example 1 1. Raw material selection and processing: Select dry, mold-free bamboo poles, remove surface impurities, crush them using a wood pulverizer, and then sieve them through a double-layer vibrating screen of 10 mesh and 5 mesh to collect bamboo particles with a particle size between 5 and 10 mesh for later use. 2. Dry distillation modification: The bamboo particles are uniformly loaded into the feed hopper of an industrial continuous carbonization furnace. The equipment is started and the residence time of the material in the furnace is controlled by adjusting the feeding speed. At the same time, the heating system is controlled to stabilize the center temperature of the furnace at 450℃±20℃. The closed structure of the furnace is used to create an oxygen-deficient environment, so that the bamboo particles are dry distilled and calcined at this temperature for 2 hours. 3. Cooling and discharge: After the dry distillation is completed, the material is transported to the furnace cooling section under closed conditions. After being naturally cooled to below 80°C, it is collected through the discharge port to obtain the bamboo fiber matrix of the present invention. Performance testing: The obtained bamboo fiber matrix was tested for its properties. The results showed that the porosity was 78%, the BET specific surface area was 350 m² / g, and the pH value was 7.2, all of which met the performance parameter range set in this invention. Example 2 1. Raw material selection and processing: Select dried bamboo, crush it and then sieve it through a vibrating screen to collect bamboo particles of 5-10 mesh, and remove dust and impurities for later use. 2. Dry distillation modification: Bamboo particles are evenly loaded into a traditional brick kiln-type carbonization furnace. After filling, the kiln opening is sealed. The furnace is ignited and heated from the outside. The ventilation inside the kiln is controlled by adjusting the damper to maintain an oxygen-deficient environment. The temperature inside the kiln is slowly raised to 400℃ and maintained at this temperature for 3 hours. 3. Cooling and discharging: After the dry distillation is completed, all vents and heating devices are closed, and the material in the kiln is allowed to simmer and cool in an oxygen-free state for 24 to 48 hours. After the temperature in the kiln drops to room temperature, the kiln is opened and the product is taken out to obtain the bamboo fiber matrix of the present invention. Performance testing: The obtained bamboo fiber matrix was tested for its properties. The results showed that the porosity was 70%, the BET specific surface area was 280 m² / g, and the pH value was 7.5, which are within the performance parameter range set in this invention. Preparation of conventional compound matrices in comparison Commercially available coconut coir and perlite were selected as raw materials and placed in a mixing device at a volume ratio of 7:3. The mixture was stirred evenly to obtain a traditional compound matrix, which served as a control sample for subsequent application tests. Application Example 1: Soilless Pot Cultivation Experiment of Blueberries in Plastic Greenhouse Experimental objective: To verify the compatibility of the bamboo fiber substrate of this invention with blueberries that prefer acidic soil and require high root aeration, and to compare its cultivation effect with that of traditional compound substrates. Experimental conditions: The experiment was conducted in a plastic greenhouse. Three-year-old blueberry seedlings (variety 'O'Neill') were selected and planted in 5-gallon plastic potted containers. Ten experimental seedlings were set up for each treatment, and the experiment was repeated 3 times. The growth environment (temperature, humidity, light) and pest and disease control measures of all experimental seedlings were kept consistent. Experimental Groups: Experimental group: The bamboo fiber substrate prepared in Example 1 was used as the single substrate, and blueberry seedlings were planted after being directly filled into potted containers; Control group: Blueberry seedlings were planted in pots filled with traditional V-shaped compound substrate (peat moss:vermiculite:perlite = 5:3:2, volume ratio). Cultivation and management: All experimental seedlings were irrigated with the same blueberry-specific acidic nutrient solution via drip irrigation, with the pH of the irrigation water adjusted to 4.5–5.5, and the substrate moisture kept stable. Routine pest and disease control was also carried out. Experimental Results and Analysis: 1. Survival rate: The survival rate of blueberry seedlings in both the experimental group and the control group was 100%, indicating that the bamboo fiber substrate of the present invention can meet the growth needs of blueberry seedlings in the early stage of planting. 2. Plant growth status: After 6 months of cultivation, the blueberry plants in the experimental group had dark green and glossy leaves, no nutrient deficiency symptoms or poor root growth, and the average growth of new shoots was 15% higher than that of the control group, indicating that the bamboo fiber substrate has better nutrient adsorption and supply capacity. 3. Root health: Observation after removing the plant from the pot at the end of cultivation showed that the substrate in the experimental group was loose and not compacted, and the blueberry roots were healthy white with well-developed fibrous roots, which were significantly more numerous than those in the control group. This indicates that the porous structure of the bamboo fiber substrate provided a more suitable aeration environment for the growth of blueberry roots. Experimental conclusion: Although the bamboo fiber substrate of this invention is weakly alkaline, it can flexibly adjust the rhizosphere environment when combined with acidic nutrient solution irrigation, fully meeting the blueberry's needs for root aeration and nutrient supply. The cultivation effect is better than that of traditional compound substrates, and it can be used as a high-quality single substrate for soilless blueberry cultivation. Application Example 2: Soilless Pot Cultivation Experiment of Tomatoes in Plastic Greenhouse Experimental objective: To verify the supporting effect of the bamboo fiber substrate of this invention on tomatoes with high fertilizer and water requirements and long growth cycles, and to compare its differences in yield and quality with conventional compound substrates. Experimental conditions: The experiment was conducted in a plastic greenhouse. 'Millennium' cherry tomato plug seedlings were selected and transplanted into 2-gallon cultivation bags. Each treatment had 15 bags of experimental seedlings, and the experiment was repeated 3 times. The growth environment and pruning method of all experimental seedlings were kept consistent. Experimental Groups: Experimental group: The bamboo fiber substrate prepared in Example 1 was used as the single substrate, and tomato seedlings were planted after being directly filled into cultivation bags; Control group: Tomato seedlings were planted in cultivation bags filled with a commonly used compound substrate (coconut coir: perlite = 7:3, volume ratio) by local vegetable farmers. Cultivation and management: All experimental seedlings were treated with a uniform tomato nutrient solution formula, and nutrients and water were supplied quantitatively through a drip irrigation system. Single-stem pruning management was implemented, and routine pest and disease control was carried out. Growth data and yield indicators were recorded throughout the entire growth period (90-day harvest period). Experimental Results and Analysis: 1. Seedling establishment and early growth: The experimental group of tomato seedlings established faster than the control group. In the early stage, the plants grew vigorously with thick stems. The leaf thickness and chlorophyll content were not significantly different from the control group, indicating that the bamboo fiber substrate can quickly adapt to the growth needs of tomato seedlings. 2. Flowering, fruit setting, yield and quality: The fruit setting rate of the first inflorescence of tomatoes in the experimental group was similar to that of the control group. The average soluble solids (sugar content) of the fruit was 0.5% to 0.8% higher than that of the control group. The cumulative yield per plant during the harvest period was 8% higher than that of the control group. This indicates that the water and fertilizer retention capacity of bamboo fiber substrate can improve the quality and yield of tomato fruit. 3. Root system and disease status: After the growing season, the substrate structure in the cultivation bags of the experimental group remained intact, with no collapse or waterlogging. The tomato roots were vigorous, and no symptoms of soil-borne diseases such as root rot were found. In the control group, some plants showed yellowing of the bottom leaves, which was presumably related to the decreased aeration of the substrate in the later stage. Experimental conclusion: The bamboo fiber substrate of this invention can provide a stable rhizosphere environment for tomatoes throughout their entire growth cycle. Its excellent water and fertilizer retention capacity and aeration can improve tomato yield and quality, and effectively prevent soil-borne diseases. It outperforms traditional coconut coir compound substrates and is suitable for soilless tomato cultivation. In summary, the bamboo fiber substrate provided by this invention, as a single-type soilless cultivation substrate, can be successfully applied to different economic crops (blueberries and tomatoes) with vastly different requirements for growth environment. The cultivation effect is superior to that of traditional compound substrates, which fully demonstrates its outstanding substantive features and significant progress as an "invention of omitted elements" and has broad prospects for industrial application. The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations, substitutions, or improvements that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention is determined by the scope of the claims.

Claims

1. A method for preparing a bamboo fiber substrate for hydroponics, characterized in that, Includes the following steps: S1. Raw material processing: Bamboo is selected as the raw material, and after crushing, bamboo particles with a particle size of 5 to 10 mesh are collected by sieving. S2. Modification treatment: The bamboo particles obtained in step S1 are placed in a conventional carbonization furnace and subjected to low-temperature dry distillation and calcination under oxygen-deficient conditions. After cooling, the bamboo fiber matrix is ​​obtained.

2. The preparation method according to claim 1, characterized in that, In step S2, the temperature of the low-temperature dry distillation calcination is 300℃~600℃.

3. The preparation method according to claim 2, characterized in that, The temperature of the low-temperature dry distillation and calcination is 400℃~500℃.

4. The preparation method according to claim 1, characterized in that, In step S2, the oxygen-deficient conditions are achieved through the closed structure of a conventional carbonization furnace. During the dry distillation process, the bamboo particles consume oxygen in the furnace and generate combustible gas, thus creating a self-generated oxygen-deficient environment.

5. The preparation method according to claim 1, characterized in that, In step S2, the dry distillation and calcination time is 1 to 3 hours.

6. A bamboo fiber matrix prepared by any one of claims 1 to 5.

7. The bamboo fiber matrix according to claim 6, characterized in that, The porosity of the bamboo fiber matrix is ​​60%–85%, and the specific surface area is ≥200 m² / g.

8. The bamboo fiber matrix according to claim 6, characterized in that, The pH value of the bamboo fiber matrix is ​​6.5 to 8.

0.

9. The use of bamboo fiber substrate as a plant cultivation substrate according to any one of claims 6 to 8.

10. The application according to claim 9, characterized in that, The bamboo fiber substrate is used directly as a single cultivation substrate to replace the traditional mixed cultivation substrate composed of two or more materials selected from coconut coir, peat, perlite, and vermiculite.

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