Application of organic household waste biochar in tea garden soil improvement and tea quality improvement

Abstract

This invention discloses the application of organic household waste biochar in tea garden soil improvement and tea quality enhancement, belonging to the field of soil improvement technology. This application uses organic household waste as raw material, and the biochar prepared through pretreatment, oxygen-limited carbonization, and product collection is applied to tea garden soil to achieve soil improvement and / or tea quality enhancement. During the biochar preparation process, the target temperature for the oxygen-limited carbonization stage is 300℃~500℃, the heating rate is 7~9℃ / min, and the holding time is no less than 60 hours. The biochar is applied by trenching and fertilizing between tea rows followed by landfilling, with an application rate of 0.8~1.2kg / m², which is particularly suitable for tea garden soil. This invention overcomes the limitations of a single resource utilization path for organic household waste and poor adaptability of materials for tea garden soil improvement, achieving synergistic effects of solid waste resource utilization and tea garden quality enhancement. The technology is simple, low-cost, suitable for large-scale promotion, and has both environmental and agricultural application value.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology, and in particular relates to the application of organic household waste biochar in tea garden soil improvement and tea quality enhancement. Background Technology

[0002] Biochar, with its unique physicochemical properties and long-term stability, has become a highly regarded sustainable soil amendment material in agriculture. Existing research confirms that biochar can improve soil structure, increase soil organic matter content, regulate soil pH, and enhance soil nutrient reserves. It can also regulate the availability of soil nutrients, thereby promoting plant growth and increasing crop yield. In tea garden management, the application of biochar has been proven to improve the moisture and nutrient status of acidic tea garden soils, playing a positive role in increasing tea yield and quality.

[0003] At the same time, household waste management is a major environmental challenge facing cities around the world, with organic household waste accounting for as much as 60%.

[0004] Currently, converting organic household waste into biochar through thermochemical technologies such as pyrolysis and carbonization is one of the effective ways to utilize it as a resource. However, existing research and applications are mostly concentrated in the field of wastewater treatment, with relatively few studies on its application in soil remediation, especially reports on the use of organic household waste biochar in tea garden soil improvement. Furthermore, existing research on biochar for soil improvement mostly uses agricultural organic waste with a single composition as raw material. Organic household waste has a complex composition, and different preparation conditions (such as pyrolysis temperature) significantly affect the physicochemical properties of its biochar, leading to variations in its effectiveness in soil improvement. Moreover, most studies focus on major crops such as rice and corn, while research on the application effects and mechanisms of action on cash crops like tea remains limited, failing to provide scientific basis and technical support for the rational application of organic household waste biochar in tea garden soil.

[0005] In summary, the problem of soil degradation in tea gardens urgently needs to be addressed. Biochar is an ideal soil amendment material, and the resource utilization of organic household waste is in dire need. However, the application of organic household waste biochar in tea garden soil improvement and tea quality enhancement is currently lacking. Therefore, developing a technology for tea garden soil improvement and tea quality enhancement based on organic household waste biochar can not only achieve high-value resource utilization of organic household waste, but also effectively improve tea garden soil quality, increase tea yield and quality, and align with sustainable agricultural development, thus possessing significant practical significance and application value. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an application of organic household waste biochar in tea garden soil improvement and tea quality enhancement. It aims to break through the limitations of existing organic household waste resource utilization pathways and poor adaptability of tea garden acidic soil improvement materials, and achieve synergy between solid waste resource utilization and tea garden soil and tea system quality enhancement.

[0007] This invention provides an application of organic household waste biochar in tea garden soil improvement and tea quality enhancement. Biochar prepared by oxygen-limited carbonization of organic household waste is applied to tea garden soil to achieve soil improvement and / or tea quality enhancement.

[0008] Furthermore, the preparation of the organic household waste biochar includes the following steps:

[0009] (1) Raw material pretreatment: Select organic household waste, mix it evenly, take samples, and then perform water filtration, drying and crushing treatment in sequence;

[0010] (2) Oxygen-limited carbonization: The pretreated raw material is sent into a closed carbonization furnace, heated to the target carbonization temperature in an oxygen-limited environment, and then kept warm until the raw material is completely carbonized.

[0011] (3) Product collection: After natural cooling, the organic household waste biochar is obtained.

[0012] Furthermore, the target carbonization temperature in step (2) is 300℃~500℃.

[0013] Furthermore, the heat preservation treatment in step (2) shall last for no less than 60 hours.

[0014] Furthermore, in step (2), the carbonization heating rate is 7~9℃ / min.

[0015] Furthermore, the biochar is applied at a rate of 0.8–1.2 kg / m², and is applied by digging a furrow (about 20 cm deep) between the tea garden ridges, applying the fertilizer, and then backfilling it.

[0016] Furthermore, the tea garden soil is acidic, and the application of biochar can improve the water retention capacity and / or nutrient status of the tea garden soil.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. Achieve high-value utilization of organic household waste resources, transforming urban solid waste into special improvement materials for tea gardens, which reduces solid waste pollution and lowers soil improvement costs, in line with the concept of low-carbon and environmental protection.

[0019] 2. Specifically adapted to acidic soils in tea gardens, effectively improving soil water retention capacity and nutrient supply, alleviating soil degradation problems, and enhancing soil ecological functions;

[0020] 3. The technical process is simple, the application rate is easy to control, and the application method is convenient. No complicated equipment is required, making it suitable for large-scale promotion and application in tea gardens. Attached Figure Description

[0021] Figure 1 NMDS analysis diagrams of organic municipal solid waste biochar prepared at different temperatures; Figure 1 (a) shows the NMDS analysis of the physicochemical properties of biochar; Figure 1 (b) shows the NMDS analysis of nutrient content in biochar;

[0022] Figure 2 Analysis of the differences in specific surface area, total pore volume at a single point, and pH of organic municipal solid waste biochar prepared at different temperatures; Figure 2 (b) shows the total pore volume analysis at a single point for biochar; Figure 2 (c) shows the pH analysis of biochar; * indicates a significant difference between the two groups at the 0.05 level, ** indicates a significant difference at the 0.01 level, and *** indicates a significant difference at the 0.001 level. Figure 2 (a) shows the specific surface area analysis of biochar;

[0023] Figure 3 Analysis of the differences in phosphorus, copper, cadmium, and lead content in organic household waste biochar prepared at different temperatures; Figure 3 (a) shows the phosphorus content analysis of biochar; Figure 3 (b) shows the copper content analysis for biomass; Figure 3 (c) shows the cadmium content analysis of biochar; Figure 3 (d) shows the lead content analysis for biochar;

[0024] Figure 4 To account for the differences in soil physicochemical properties under different treatments; Figure 4 (a) shows the soil bulk density analysis after biochar application; Figure 4 (b) shows the analysis of soil field water holding capacity after biochar application; Figure 4 (c) shows the soil saturated moisture content analysis after biochar application; Figure 4 (d) represents the soil pH analysis after biochar application;

[0025] Figure 5 The difference in total nutrient content in soil under different treatments. Figure 5 (a) shows the analysis of total nitrogen content in the soil after biochar application; Figure 5 (b) shows the analysis of total phosphorus content in the soil after biochar application; Figure 5(c) shows the analysis of total potassium content in the soil after biochar application; Figure 5 (d) shows the analysis of soil organic carbon content after biochar application;

[0026] Figure 6 The difference in available nutrient content in soil under different treatments; Figure 6 (a) shows the analysis of soil ammonium nitrogen content after biochar application; Figure 6 (b) shows the analysis of soil nitrate nitrogen content after biochar application; Figure 6 (c) shows the analysis of available phosphorus content in the soil after biochar application; Figure 6 (d) shows the analysis of available potassium content in the soil after biochar application;

[0027] Figure 7 The differences in tea yield and theanine and tea polysaccharide content under different treatments; Figure 7 (a) shows the weight analysis of 100 tea buds after biochar application; Figure 7 (b) shows the tea yield content analysis after biochar application; Figure 7 (c) shows the analysis of theanine content in tea leaves after biochar application; Figure 7 (d) shows the analysis of tea polysaccharide content in tea leaves after biochar application. Detailed Implementation

[0028] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1: Preparation of biochar from organic household waste

[0030] 1. Preparation process of biochar from organic household waste

[0031] (1) Raw material collection and pretreatment: Randomly select a truckload of fresh organic domestic waste from the organic domestic waste collection center, mix it thoroughly and evenly, and take 200 kg of sample as raw material for preparation; transfer the raw material to the domestic waste resource treatment center in Youxi Town, where it is subjected to water filtration, drying and crushing treatment in sequence to ensure that the subsequent carbonization reaction is uniform and sufficient.

[0032] (2) Carbonization preparation: The pretreated organic household waste raw material is sent to a closed carbonization furnace (produced by Nanjing Zhironglian Technology Co., Ltd.). The carbonization reaction is carried out under the limited oxygen environment with the carbonization temperature controlled at 300℃ and 500℃ respectively. The carbonization heating rate is 8.5℃ / min, and the heat preservation treatment is not less than 60 hours. After the carbonization is completed, it is naturally cooled to room temperature to obtain two kinds of organic household waste biochar prepared at different temperatures.

[0033] 2. Detection of physicochemical properties and nutrient content of biochar

[0034] (1) Pore characteristics detection: The porosity, specific surface area and total pore volume of biochar at a single point were determined by the multi-point BET method;

[0035] (2) pH value detection: pH value was determined using the biochar:water (1:2.5) method;

[0036] (3) Detection of major nutrients: Total nitrogen content was determined by the Kjeldahl method, and total phosphorus content was determined by the ammonium molybdate spectrophotometric method;

[0037] (4) Metal element detection: After the biochar sample is digested by microwave digester, the content of metal nutrient elements (potassium, sodium, magnesium, iron, calcium, zinc, copper, manganese) and heavy metal elements (chromium, cadmium, lead) is determined by inductively coupled plasma mass spectrometry.

[0038] 3. Analysis of test results

[0039] Nonmetric multidimensional scaling (NMDS) analysis results showed that the comprehensive physicochemical properties of organic municipal solid waste biochar prepared at different temperatures differed significantly. Figure 1 a). Organic municipal solid waste biochar prepared at 500℃ has a large specific surface area, high total pore volume at a single point, and a high pH value (P<0.05). Figure 2 Nonmetric multidimensional scaling (NMDS) analysis results showed no significant difference in the comprehensive nutrient content of organic municipal solid waste biochar prepared at different temperatures. Figure 1 b). The inter-group differences in nutrient elements (nitrogen, phosphorus, potassium, sodium, magnesium, iron, calcium, zinc, copper, manganese) and heavy metal elements (chromium, cadmium, lead) showed that the organic waste biochar prepared at 500℃ had a significant enrichment effect on the nutrient element phosphorus and the heavy metal elements copper, cadmium, and lead (P<0.05). Figure 3 ).

[0040] Example 2: Application of Organic Household Waste Biochar in Soil Improvement and Tea Quality Enhancement in Tea Gardens

[0041] 2.1 Overview of the Experimental Tea Garden

[0042] The experiment was conducted in a tea garden in Lanliao Forest Farm. The tea variety used was Fuding Dabai, planted in 1992. The soil type in the tea garden was yellow soil, and the initial soil physicochemical properties were: pH 5.25, total nitrogen 3.22 g / kg, total phosphorus 1.68 g / kg, total potassium 19.7 g / kg, organic carbon 47.8 g / kg, ammonium nitrogen 7.56 mg / kg, and nitrate nitrogen 3.62 mg / kg.

[0043] 2.2 Experimental Design

[0044] This experiment used a randomized block design, with a total of 4 treatment groups, each with 3 replicates. The specific treatment scheme is as follows:

[0045] Control group 1 (no fertilizer): No fertilizer was applied;

[0046] Control group 2 (compound fertilizer treatment): Conventional compound fertilizer (N:P:K=14:16:15) was applied at a rate of 0.12 kg / m³. 2 ;

[0047] Experimental group 1 (300℃): Biochar prepared in Example 1 was applied at 300℃ at an application rate of 1 kg / m².

[0048] Experimental group 2 (500℃): Biochar prepared in Example 1 at 500℃ was applied at a rate of 1 kg / m².

[0049] Each plot has an area of ​​4m×4m=16m², with 1m wide isolation rows between plots; field management measures (weeding, irrigation, pest and disease control, etc.) are kept completely consistent across all treatment groups. Fertilization will be carried out in October 2023, using a method of applying fertilizer in furrows (about 20cm deep) between tea garden rows and then backfilling it.

[0050] 2.3 Sample Collection and Testing

[0051] 2.3.1 Soil sample collection and processing:

[0052] Sample collection: Samples were collected one and a half years after fertilization (April 20, 2025). A five-point sampling method was used in each plot. Topsoil (0-10cm) and subsoil (10-30cm) samples were collected using a soil auger. Each soil sample was a mixture of soil from the five sampling points, placed in a sealed bag, and quickly brought back to the laboratory.

[0053] Sample preparation: After removing plant and animal remains, gravel and other impurities from the sample, pass it through a 2mm sieve and divide it into two portions. One half of the sample is stored in a sealed bag in a 4℃ refrigerator, and the other half is placed on kraft paper, air-dried at room temperature and then sealed for subsequent determination.

[0054] 2.3.2 Soil index testing:

[0055] Soil moisture content was determined by oven drying; soil bulk density was determined by ring cutter method; soil pH was determined by soil:water (1:2.5) method; soil organic carbon content was determined by potassium dichromate external heating method; soil total nitrogen was determined by Kjeldahl method; soil total phosphorus content was determined by continuous flow analysis method; ammonium nitrogen and nitrate nitrogen were determined by potassium chloride solution extraction-spectrophotometry; microbial biomass carbon and nitrogen were determined by chloroform fumigation-instrumental analysis method; available phosphorus was determined by NaHCO3 method; and available potassium was determined by flame photometry.

[0056] 2.3.3 Measurement of tea yield and quality:

[0057] Tea yield determination: The bud density of tea trees was investigated using a 33 cm × 33 cm sample frame. All buds (one bud and one leaf) within the sample frame were picked, and the fresh weight of 100 buds was randomly selected and weighed. After drying in an oven at 75℃, the dry weight of 100 buds was weighed.

[0058] Tea quality indicators were determined as follows: theanine was determined by high performance liquid chromatography; tea polysaccharides were determined by the anthrone-sulfuric acid method; and trace elements were determined by inductively coupled plasma mass spectrometry after acid digestion using a microwave digester.

[0059] 2.4 Results Analysis

[0060] 2.4.1 Impact on the physicochemical properties of tea garden soil

[0061] The results showed that the addition of organic household waste biochar had no significant effect on soil bulk density, saturated water content, or pH. Compared to no fertilization, application of organic household waste biochar prepared at 300℃ significantly increased the field water holding capacity of the subsoil (10–30 cm). Compared to no fertilization and the application of compound fertilizer, application of organic household waste biochar prepared at 300℃ slightly improved the bulk density and saturated water content of the subsoil (10–30 cm), while application of organic household waste biochar prepared at 500℃ slightly improved the bulk density, field water holding capacity, and saturated water content of the topsoil (0–10 cm). However, these improvements were not significant. There was no significant difference in soil bulk density among different soil layers under each treatment, but there were significant differences in field water holding capacity and saturated water content among soil layers after application of organic household waste biochar prepared at 300℃ (P<0.05). The soil pH of soil layers treated with organic household waste biochar prepared at 500℃ showed significant differences (P<0.05).

[0062] 2.4.2 Impact on soil nutrient content in tea gardens

[0063] Compared with no fertilizer and the application of compound fertilizer, the application of organic household waste biochar has a lower effect on the total nitrogen content of the upper subsoil. Figure 5 a) and total phosphorus content in topsoil ( Figure 5 (b) Both showed an increase, but the statistical significance was not significant. The use of organic household waste biochar had no significant effect on the organic carbon content of topsoil and subsoil. Figure 5 d). Application of organic household waste biochar prepared at 300℃ significantly increased the total potassium content of topsoil (P<0.05). Figure 5 c). Significant differences were observed in the total nitrogen content between soil layers in treatments without fertilization and those using organic municipal solid waste biochar prepared at 300°C. Figure 5 a) The total potassium content between soil layers was significantly different under the no-fertilization treatment. Figure 5 c). Compared to no fertilization and the application of compound fertilizer, the application of organic household waste biochar had no significant effect on the content of available nutrients (ammonium nitrogen, nitrate nitrogen, available phosphorus, and available potassium) in the soil. Figure 6 Compared to no fertilizer application and compound fertilizer application, the application of organic household waste biochar slightly increased the available phosphorus content in the upper subsoil and the nitrate nitrogen content in the topsoil, while slightly decreasing the ammonium nitrogen content in the topsoil and the available potassium content in the subsoil.

[0064] 2.4.3 Impact on tea yield and quality

[0065] Compared with no fertilizer application and the application of compound fertilizer, the application of organic household waste biochar had no significant impact on the yield and quality of tea. Figure 7 Compared to no fertilizer application, the tea yield of tea gardens using biochar was slightly increased, but the weight of 100 buds was slightly reduced, and the content of tea polysaccharides and theanine was slightly reduced, but none of these were significant.

[0066] This invention produces organic household waste biochar using a specific process and applies it to tea garden soil improvement. The process is simple, low-cost, and enables the resource utilization of organic household waste. Experimental results show that this biochar has potential for improving tea garden soil, increasing soil nutrient content and tea yield.

[0067] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. The application of organic household waste biochar in tea garden soil improvement and tea quality enhancement, characterized in that, Biochar prepared from organic household waste through oxygen-limited carbonization is applied to tea garden soil to improve soil quality and / or enhance tea quality.

2. The application according to claim 1, characterized in that, The preparation of the organic household waste biochar includes the following steps: (1) Raw material pretreatment: Select organic household waste, mix it evenly, take samples, and then perform water filtration, drying and crushing treatment in sequence; (2) Oxygen-limited carbonization: The pretreated raw material is sent into a closed carbonization furnace, heated to the target carbonization temperature in an oxygen-limited environment, and then kept warm until the raw material is completely carbonized. (3) Product collection: After natural cooling, the organic household waste biochar is obtained.

3. The application according to claim 2, characterized in that, The target carbonization temperature in step (2) is 300℃~500℃.

4. The application according to claim 2, characterized in that, The heat preservation treatment in step (2) shall last for no less than 60 hours.

5. The application according to claim 2, characterized in that, In step (2), the carbonization heating rate is 7~9℃ / min.

6. The application according to claim 1, characterized in that, The biochar application rate is 0.8–1.2 kg / m², and the application method is to apply fertilizer by digging trenches between tea garden ridges and then burying it.

7. The application according to claim 1, characterized in that, The tea garden soil is acidic, and the application of biochar can improve the water retention capacity and / or nutrient status of the tea garden soil.

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