Application of modified biochar in prevention and treatment of bacterial wilt of vegetable

Abstract

The application discloses application of modified biochar in prevention and treatment of vegetable bacterial wilt, and the modified biochar is biochar modified by a sodium silicate solution.In the application, biomass is soaked in the sodium silicate solution, and then pyrolysis and carbonization are carried out, so that the modified biomass with a large surface area, a high pH value and rich silicon content is obtained.The modified biochar can be used as base fertilizer of vegetables, can effectively improve the soil environment, can fully play the effect and performance of silicon and biochar, can improve the prevention and treatment effect of biochar on the bacterial wilt, and can effectively degrade the bacterial wilt, so that the application has very important significance in agriculture.

Description

Technical Field

[0001] This invention belongs to the field of agricultural production technology, and more specifically, this invention relates to the application of modified biochar in the prevention and control of bacterial wilt in vegetables. Background Technology

[0002] Bacterial wilt is a vascular disease caused by the fungus *Ralstonia solanacearum*. It typically invades the host's roots through the soil and actively colonizes the xylem vessels, causing wilting symptoms. *Ralstonia solanacearum* is a major cause of fatal wilt in more than 200 plant species, resulting in significant crop losses.

[0003] Currently, many strategies for controlling bacterial wilt have been proposed, such as the use of chemical fungicides, biological control agents, physical methods, and cultivation methods. However, these methods have limited effectiveness and can result in pesticide residues. Therefore, adopting other effective measures to control the damage caused by bacterial wilt has become an important issue that urgently needs to be addressed in vegetable production.

[0004] Silicon is the second most abundant element in the Earth's crust. It can enhance plant resistance to various abiotic (such as drought, salt, and heavy metal stress) and biotic stresses. For example, silicon treatment can significantly reduce the incidence and disease index of rice blast in four rice varieties with different resistance levels, and can significantly improve the resistance of Chinese cabbage to anthracnose, cucumber to Pythium, the migration of Pythium spp. in the roots of bitter gourd, and cucumber to powdery mildew.

[0005] Biochar is a stable, carbon-rich product produced by the high-temperature pyrolysis (above 250℃) of biomass (such as wood, agricultural waste, and livestock manure) in a closed container with low or no oxygen. Due to its porous structure, large specific surface area, abundant hydroxyl and carboxyl functional groups, and high charge density of aromatic ring structures, biochar possesses strong ion exchange and adsorption capabilities. In recent years, biochar has shown broad application potential as a soil conditioner in environmental, energy, agricultural, and industrial fields. However, biochar itself has a low silicon content, resulting in insufficient effects on enhancing plant disease resistance.

[0006] Sodium silicate solution-modified biochar mainly employs physical and chemical modification methods to process and modify biochar raw materials, thereby increasing or altering their elemental composition. Currently, research on modified biochar primarily focuses on the adsorption and treatment of heavy metals; no studies have yet found applying sodium silicate solution-modified biochar to the prevention and control of bacterial wilt in vegetables. Summary of the Invention

[0007] Based on this, the purpose of the present invention is to provide an application of modified biochar in the prevention and control of bacterial wilt in vegetables and a method for preventing and controlling bacterial wilt in vegetables.

[0008] The technical solutions for achieving the above-mentioned objectives include the following.

[0009] The first aspect of the present invention is to provide an application of modified biochar in the prevention and control of bacterial wilt in vegetables, wherein the modified biochar is biochar modified with silicon solution.

[0010] A second aspect of the present invention is to provide a method for preventing and controlling bacterial wilt in vegetables.

[0011] The method for preventing and controlling bacterial wilt in vegetables includes the following steps: using modified biochar as a base fertilizer for vegetables, wherein the modified biochar is biochar modified with silicon solution.

[0012] In this invention, modified biomass with a smaller specific surface area, higher pH, and richer silicon content is obtained by soaking biomass in a silicon solution and then pyrolyzing and carbonizing it. Using the modified biochar as a base fertilizer for vegetables can effectively improve the soil environment (increase soil pH), fully utilize the effects and properties of silicon and biochar, improve the control effect of biochar on bacterial wilt, and effectively reduce the severity of bacterial wilt disease. This has very important significance in agriculture. Attached Figure Description

[0013] Figure 1 This is an electron microscopy-energy dispersive spectroscopy (EDS) image of the modified biochar in Example 1 of this invention.

[0014] Figure 2 This is an electron microscopy-energy dispersive spectroscopy (EDS) image of the modified biochar in Example 2 of the present invention.

[0015] Figure 3 This is an electron microscopy-energy dispersive spectroscopy (EDS) image of the modified biochar in Example 3 of the present invention.

[0016] Figure 4 This is an electron microscopy-energy dispersive spectroscopy (EDS) image of the biochar in Comparative Example 1 of this invention.

[0017] Figure 5 This is an electron microscopy-energy dispersive spectroscopy (EDS) image of the biochar in Comparative Example 2 of this invention.

[0018] Figure 6 This is an electron microscopy-energy dispersive spectroscopy (EDS) image of the biochar in Comparative Example 3 of this invention.

[0019] Figure 7 The image shows a comparison of the infrared spectra of biochar in Example 1 and Comparative Example 1 of this invention.

[0020] Figure 8 The infrared spectra of biochar in Example 2 and Comparative Example 2 of this invention are compared.

[0021] Figure 9 The image shows a comparison of the infrared spectra of biochar in Example 3 and Comparative Example 3 of this invention.

[0022] Figure 10 The results show the incidence rates of bacterial wilt in each experimental group in Experiment Example 3 of this invention.

[0023] Figure 11 The results show the fresh weight of tomato plants in each experimental group in Experiment Example 3 of this invention.

[0024] Figure 12 The soil pH results for each experimental group in Experiment Example 3 of this invention are shown.

[0025] Figure 13 The soil EC results for each experimental group in Experiment Example 3 of this invention are shown.

[0026] Figure 14 The results show the effective silicon content of the soil in each experimental group in Experiment Example 3 of this invention.

[0027] Figure 15 The soil C / N ratio results are shown for each experimental group in Experiment Example 3 of this invention. Detailed Implementation

[0028] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0030] Unless otherwise specified, experimental methods in the following examples were performed under standard conditions, such as those described in Green and Sambrook et al., *Molecular Cloning: A Laboratory Manual* (2013), or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0031] In some embodiments of the present invention, the application of modified biochar in the prevention and control of bacterial wilt in vegetables is disclosed, wherein the modified biochar is biochar modified with silicon solution.

[0032] In some embodiments, the silicon solution is a sodium silicate solution.

[0033] In some embodiments, the modified biochar is biochar made from Canadian goldenrod, rice straw, corn straw, and soybean straw modified with sodium silicate solution.

[0034] In some embodiments, the modified biochar is Canadian goldenrod modified with sodium silicate solution. The antibacterial effect is best when the biochar is Canadian goldenrod, possibly because Canadian goldenrod contains a certain amount of goldenrod essential oil, which helps inhibit the growth of pathogens.

[0035] In some embodiments, the modified biochar is prepared by the following method: Canadian goldenrod powder is placed in a sodium silicate solution, stirred, centrifuged, dried, and then pyrolyzed and carbonized under oxygen-limited or oxygen-deficient conditions to obtain modified biochar. The preparation process of modified biochar is simple, non-toxic, and harmless, requires no multiple reactions, and has low requirements for the preparation environment, making it beneficial for practical application in production.

[0036] In some embodiments, the pyrolysis carbonization temperature is 450–650°C, and the heating rate is 5°C / min–10°C / min.

[0037] In some embodiments, the pyrolysis carbonization is carried out in a drawer-type carbonization furnace, and the pyrolysis carbonization time is 100 min to 140 min.

[0038] In some embodiments, nitrogen protection is used during the pyrolysis carbonization process, with a nitrogen flow rate of 2 ml / min to 3 ml / min.

[0039] In some embodiments, the stirring temperature is 28°C to 32°C, the stirring speed is 120 r / min to 180 r / min, and the stirring time is 150 min to 200 min, which can achieve sufficient modification of Canadian goldenrod by sodium silicate solution.

[0040] In some embodiments, the sodium silicate solution has a mass concentration of 5% to 15%.

[0041] In some embodiments, the mass-to-volume ratio of the Canadian goldenrod stalk to the sodium silicate solution is 1:12-18.

[0042] In other embodiments of the present invention, a method for preventing and controlling bacterial wilt of vegetables is also disclosed.

[0043] The method for preventing and controlling bacterial wilt in vegetables includes the following steps: using the modified biochar described above as a base fertilizer for planting vegetables.

[0044] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Example 1: Modified biochar and its preparation method

[0046] This embodiment provides a sodium silicate-modified biochar, which is prepared by the following method:

[0047] (1) Take Canadian goldenrod stalks, soak and wash them in ultrapure water, dry them at 85℃ and crush them through a 100-mesh sieve;

[0048] (2) Dissolve 50g of sodium silicate in 500ml of ultrapure water to obtain a 10wt% sodium silicate solution;

[0049] (3) Dissolve 20g of Canadian goldenrod stalk powder in 300ml of 10wt% sodium silicate solution, maintain 30℃, and stir for 180 minutes (keeping the speed at 150r / min).

[0050] (4) Centrifuge at 4000r / min for 4-5 times, 15min / time;

[0051] (5) The centrifuged solid raw material was placed in an oven to dry at 80℃ for 120 minutes. This yielded sodium silicate-modified Canadian goldenrod stalk material.

[0052] (6) The modified raw material is placed in a drawer-type carbonization furnace, filled with nitrogen, and carbonized at a constant temperature of 450℃ for 2 hours to obtain sodium silicate modified biochar.

[0053] Example 2 Modified biochar and its preparation method

[0054] This embodiment provides a sodium silicate-modified biochar, which is prepared by the following method:

[0055] (1) Take Canadian goldenrod stalks, soak and wash them in ultrapure water, dry them at 85℃ and crush them through a 100-mesh sieve;

[0056] (2) Dissolve 50g of sodium silicate in 500ml of ultrapure water to obtain a 10wt% sodium silicate solution;

[0057] (3) Dissolve 20g of Canadian goldenrod stalk powder in 300ml of 10wt% sodium silicate solution, maintain 30℃, and stir for 180 minutes (keeping the speed at 150r / min).

[0058] (4) Centrifuge at 4000r / min for 4-5 times, 15min / time;

[0059] (5) The centrifuged solid raw material was placed in an oven to dry at 80℃ for 120 minutes. This yielded sodium silicate-modified Canadian goldenrod stalk material.

[0060] (6) The modified raw material is placed in a drawer-type carbonization furnace, filled with nitrogen, and carbonized at a constant temperature of 550℃ for 2 hours to obtain sodium silicate modified biochar.

[0061] Example 3 Modified biochar and its preparation method

[0062] This embodiment provides a sodium silicate-modified biochar, which is prepared by the following method:

[0063] (1) Take Canadian goldenrod stalks, soak and wash them in ultrapure water, dry them at 85℃ and crush them through a 100-mesh sieve;

[0064] (2) Dissolve 50g of sodium silicate in 500ml of ultrapure water to obtain a 10wt% sodium silicate solution;

[0065] (3) Dissolve 20g of Canadian goldenrod stalk powder in 300ml of 10wt% sodium silicate solution, maintain 30℃, and stir for 180 minutes (keeping the speed at 150r / min).

[0066] (4) Centrifuge at 4000r / min for 4-5 times, 15min / time;

[0067] (5) The centrifuged solid raw material was placed in an oven to dry at 80℃ for 120 minutes. This yielded sodium silicate-modified Canadian goldenrod stalk material.

[0068] (6) The modified raw material is placed in a drawer-type carbonization furnace, filled with nitrogen, and carbonized at a constant temperature of 650℃ for 2 hours to obtain sodium silicate modified biochar.

[0069] Example 4 Modified biochar and its preparation method

[0070] This embodiment provides a sodium silicate-modified biochar, which is prepared by the following method:

[0071] (1) Take Canadian goldenrod stalks, soak and wash them in ultrapure water, dry them at 85℃ and crush them through a 100-mesh sieve;

[0072] (2) Dissolve 50g of sodium silicate in 500ml of ultrapure water to obtain a 5wt% sodium silicate solution;

[0073] (3) Dissolve 20g of Canadian goldenrod stalk powder in 300ml of 5wt% sodium silicate solution, maintain 30℃, and stir for 180 minutes (keeping the speed at 150r / min).

[0074] (4) Centrifuge at 4000r / min for 4-5 times, 15min / time;

[0075] (5) The centrifuged solid raw material was placed in an oven to dry at 80℃ for 120 minutes. This yielded sodium silicate-modified Canadian goldenrod stalk material.

[0076] (6) The modified raw material is placed in a drawer-type carbonization furnace, filled with nitrogen, and carbonized at a constant temperature of 450℃ for 2 hours to obtain sodium silicate modified biochar.

[0077] Example 5 Modified biochar and its preparation method

[0078] This embodiment provides a sodium silicate-modified biochar, which is prepared by the following method:

[0079] (1) Take rice straw, soak and wash it with ultrapure water, dry it at 85℃ and crush it through a 100-mesh sieve;

[0080] (2) Dissolve 50g of sodium silicate in 500ml of ultrapure water to obtain a 10wt% sodium silicate solution;

[0081] (3) Dissolve 20g of rice straw powder in 300ml of 10wt% sodium silicate solution, maintain 30℃, and stir for 180 minutes (keeping the speed at 150r / min);

[0082] (4) Centrifuge at 4000r / min for 4-5 times, 15min / time;

[0083] (5) Place the centrifuged solid raw material in an oven to dry at 80℃ for 120 minutes. This yields sodium silicate-modified rice straw material.

[0084] (6) The modified raw material is placed in a drawer-type carbonization furnace, filled with nitrogen, and carbonized at a constant temperature of 450℃ for 2 hours to obtain sodium silicate modified biochar.

[0085] Example 6 Modified biochar and its preparation method

[0086] This embodiment provides a sodium silicate-modified biochar, which is prepared by the following method:

[0087] (1) Take corn stalks, soak and wash them with ultrapure water, dry them at 85℃ and crush them through a 100-mesh sieve;

[0088] (2) Dissolve 50g of sodium silicate in 500ml of ultrapure water to obtain a 10wt% sodium silicate solution;

[0089] (3) Dissolve 20g of corn stalk powder in 300ml of 10wt% sodium silicate solution, maintain 30℃, and stir for 180 minutes (keeping the speed at 150r / min);

[0090] (4) Centrifuge at 4000r / min for 4-5 times, 15min / time;

[0091] (5) The centrifuged solid raw material was placed in an oven to dry at 80℃ for 120 minutes. This yielded sodium silicate-modified corn stalk material.

[0092] (6) The modified raw material is placed in a drawer-type carbonization furnace, filled with nitrogen, and carbonized at a constant temperature of 450℃ for 2 hours to obtain sodium silicate modified biochar.

[0093] Example 7 Modified biochar and its preparation method

[0094] This embodiment provides a sodium silicate-modified biochar, which is prepared by the following method:

[0095] (1) Take soybean straw, soak and wash it with ultrapure water, dry it at 85℃ and crush it through a 100-mesh sieve;

[0096] (2) Dissolve 50g of sodium silicate in 500ml of ultrapure water to obtain a 10wt% sodium silicate solution;

[0097] (3) Dissolve 20g of soybean straw powder in 300ml of 10wt% sodium silicate solution, maintain 30℃, and stir for 180 minutes (keeping the speed at 150r / min);

[0098] (4) Centrifuge at 4000r / min for 4-5 times, 15min / time;

[0099] (5) The centrifuged solid raw material was placed in an oven to dry at 80℃ for 120 minutes. This yielded sodium silicate-modified soybean straw material.

[0100] (6) The modified raw material is placed in a drawer-type carbonization furnace, filled with nitrogen, and carbonized at a constant temperature of 450℃ for 2 hours to obtain sodium silicate modified biochar.

[0101] Comparative Example 1: Biochar and its preparation method

[0102] This comparative example provides a biochar prepared by the following method:

[0103] (1) Take Canadian goldenrod stalks, soak and wash them with ultrapure water, dry them at 85°C and pulverize them through a 100-mesh sieve to obtain Canadian goldenrod stalk powder.

[0104] (2) Place the obtained raw materials in a drawer-type carbonization furnace, fill with nitrogen, maintain the temperature at 450℃ for 2 hours to carbonize, and obtain biochar.

[0105] Comparative Example 2: Biochar and its preparation method

[0106] This comparative example provides a biochar prepared by the following method:

[0107] (1) Take Canadian goldenrod stalks, soak and wash them with ultrapure water, dry them at 85°C and pulverize them through a 100-mesh sieve to obtain Canadian goldenrod stalk powder.

[0108] (2) Place the obtained raw materials in a drawer-type carbonization furnace, fill with nitrogen, maintain the temperature at 550℃ for 2 hours to carbonize, and obtain biochar.

[0109] Comparative Example 3: Biochar and its preparation method

[0110] This comparative example provides a biochar prepared by the following method:

[0111] (1) Take Canadian goldenrod stalks, soak and wash them with ultrapure water, dry them at 85°C and pulverize them through a 100-mesh sieve to obtain Canadian goldenrod stalk powder.

[0112] (2) Place the obtained raw materials in a drawer-type carbonization furnace, fill with nitrogen, maintain the temperature at 650℃ for 2 hours to carbonize, and obtain biochar.

[0113] Experimental Example 1: Comparison of the antibacterial effects of modified and unmodified biochar against Ralstonia solanacearum

[0114] In this experiment, extracts of modified biochar from Examples 1-3, modified biochar from Examples 5-7, and unmodified biochar from Comparative Examples 1-3 were used for antibacterial experiments. The modified biochar from Examples 1-3, the modified biochar from Examples 5-7, and the unmodified biochar from Comparative Examples 1-3 were prepared at a carbon:water (ultrapure water) ratio of 1:20, shaken for 30 min, filtered and sterilized, and subjected to Ralstonia solanacearum inhibition zone experiments in LB medium. After 24 h of incubation, the size of the inhibition zone was measured. The results are shown in Table 1.

[0115] Table 1

[0116]

[0117] As shown in Table 1, the antibacterial effects of sodium silicate-modified biochar (Examples 1-3 and 5-7) were improved compared with those of unmodified biochar (Comparative Examples 1-3). Compared with the modified biochar of Examples 5-7 (sodium silicate-modified rice straw, sodium silicate-modified corn straw, and sodium silicate-modified soybean straw), the antibacterial effect of sodium silicate-modified Canadian goldenrod (Examples 1-3) was significantly better.

[0118] Experimental Example 2: Morphological changes of biochar before and after modification

[0119] The scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) spectra of biochar from Examples 1-3 and Comparative Examples 1-3 are shown below. Figures 1-6 As shown in the results, the modified biochar in Examples 1-3 contains a large amount of modified Si and Na elements, while the biochar in Comparative Examples 1-3 contains only a very small amount or no related elements.

[0120] The infrared spectra of biochar from Examples 1-3 and Comparative Examples 1-3 are shown in the figures below. Figures 7-9 As shown in the results, it can be clearly seen that in the modified biochar of Examples 1-3, the biochar exhibits a significantly higher content at 985 cm⁻¹. -1 1000-1100cm -1 1428cm -1 1632cm -1 It contains stretching vibrations of Si-O-Si, Si-OH, and SiAr, while biochar in proportions of 1 to 3 does not.

[0121] The basic characterization of the biochar in Examples 1-3 and Comparative Examples 1-3 is shown in Table 3.

[0122] Table 3

[0123] Yield (%) pH CEC EC Ash content (%) Comparative Example 1 35 10.89±0.03d 28.63±2.21c 0.17±0.005f 19.93±0.11a Comparative Example 2 27 10.18±0.02f 21.27±1.19d 0.29±0.005e 22.40±4.13a Comparative Example 3 25 10.73±0.02e 20.23±1.11d 0.42±0.005d 21.34±1.34a Example 1 36.4 12.12±0.02c 45.57±0.66a 4.60±0.005b 10.00±1.00b Example 2 34.6 12.47±0.03b 36.39±1.65b 4.31±0.005c 9.67±1.53b Example 3 33 12.72±0.03a 44.76±1.05a 4.67±0.005a 11.92±1.06b

[0124] Table 3 shows that the yield of sodium silicate-modified biochar (Examples 1-3) was higher than that of unmodified biochar (Comparative Examples 1-3), and the yield decreased with increasing calcination temperature. The pH of sodium silicate-modified biochar (Examples 1-3) was significantly higher than that of unmodified biochar (Comparative Examples 1-3), and increased with increasing calcination temperature. Since *Ralstonia solanacearum* readily grows in slightly acidic soils, increasing the pH level helps inhibit its growth.

[0125] The specific surface areas of the biochar in Examples 1-3 and Comparative Examples 1-3 are shown in Table 4.

[0126] Table 4

[0127]

[0128] As shown in Table 4, compared with unmodified biochar (Comparative Examples 1-3), the BET specific surface area of ​​biochar modified with sodium silicate was significantly reduced. The reduced specific surface area makes it less likely to provide pathogens with a growth and aggregation environment and nutrients, which is more conducive to inhibiting the growth of pathogens.

[0129] Experimental Example 3: The effect of modified biochar on the control of bacterial wilt in vegetables and its effect on soil improvement.

[0130] This experiment investigated the control effects of unmodified and modified biochar on bacterial wilt of vegetables and their soil improvement effects, including the following steps:

[0131] I. Experimental Materials

[0132] Tomato seedlings (Frede 2)

[0133] II. Experimental Methods

[0134] 1. Sterilize tomato seeds (Freit No. 2) in water at 50℃ for 30 minutes. Then, sow the seeds in the substrate and cultivate them in an artificial climate chamber (day / night 28℃ / 25℃, 14 hours light per day, 200 μmol·m⁻²·min⁻¹). -2 ·s -1 (Relative humidity 70%).

[0135] 2. One month later, the tomato seedlings were transferred to pots (16cm×17cm) with soil containing 1% biochar. Two seedlings were transplanted into each pot, and the tomato plants were placed in an artificial climate chamber for growth (the growth conditions for tomato seedlings were the same as above).

[0136] 3. This experiment included 7 treatments, with all experiments repeated 3 times. Each treatment used 12 plants. The treatments are as follows:

[0137] (1) Blank control and Ralstonia solanacearum inoculation (blank control + Rs)

[0138] (2) Modified biochar and Ralstonia solanacearum inoculation in Example 1 (Example 1 + Rs)

[0139] (3) Modified biochar and Ralstonia solanacearum inoculation in Example 2 (Example 2+Rs)

[0140] (4) Modified biochar and Ralstonia solanacearum inoculation in Example 3 (Example 3+Rs)

[0141] (5) Biochar and Ralstonia solanacearum inoculation of Comparative Example 1 (Comparative Example 1 + Rs)

[0142] (6) Biochar and Ralstonia solanacearum inoculation of Comparative Example 2 (Comparative Example 2 + Rs)

[0143] (7) Biochar and Ralstonia solanacearum inoculation of Comparative Example 3 (Comparative Example 3 + Rs)

[0144] Among them, Ralstonia solanacearum (Tim17, preserved at Guangxi University) was cultured on casein peptone dextrose agar (10 g / L peptone). -1 Casein hydrolysate 1 g·L -1 5g / L glucose -1 15g / L agar -1 The bacteria were activated by adjusting the pH to 7.2 with 1N NaOH and incubated at 30°C for 48 hours. Then, the bacteria were suspended in sterile water and adjusted to OD. 600=0.1 (approximately 10) 8 CFU·mL -1 Then, use the root injury inoculation method to inoculate, pouring 50 mL of Ralstonia solanacearum suspension into each pot.

[0145] III. Experimental Results

[0146] 1. Infection rate and disease severity index

[0147] One day after inoculation, vegetables infected with bacterial wilt were scored, and the disease index was calculated.

[0148] Bacterial wilt is scored on a scale of 0 to 9. 0 indicates no obvious symptoms; 1 indicates 1 leaf wilting; 3 indicates 2-3 leaves wilting; 5 indicates all leaves except the top 1-2 leaves wilting; 7 indicates all leaves wilting; and 9 indicates the death of both leaves and the plant.

[0149] Disease index = ∑(Number of disease-severed plants + Representative value) / (Total number of plants * Representative value of the most severe disease level) * 100%

[0150] The infection rate results from day 0 to day 14 of infection are as follows: Figure 10 The infection rate results after day 14 of infection are shown in Table 5. Figure 10 As shown in Table 5, under the condition of inoculation with Ralstonia solanacearum, compared with the blank control and comparative examples 1-3, the incidence of bacterial wilt in tomatoes was significantly reduced after using the modified biochar of Examples 1-3, and the modified biochar of Example 1 had the best effect.

[0151] Table 5

[0152] Incidence rate (%) Blank control 84.72±1.20a Comparative Example 1 56.25±7.51b Comparative Example 2 57.64±3.18b Comparative Example 3 58.44±4.21b Example 1 36.11±5.24d Example 2 48.61±6.01c Example 3 52.78±3.24c

[0153] 2. Chlorophyll fluorescence (Fv / Fm)

[0154] Before inoculation and 15 days after inoculation, chlorophyll fluorescence parameters of leaves were measured using an OS-30p instrument, and the Fv / Fm values ​​of tomato chlorophyll fluorescence were determined. The results are shown in Table 6.

[0155] Table 6. Fv / Fm values ​​of tomato leaves

[0156] Tomatoes before inoculation with Ralstonia solanacearum Tomatoes inoculated with Ralstonia solanacearum blank 0.803±0.009bc 0.578±0.009c Comparative Example 1 0.812±0.003b 0.775±0.001b Comparative Example 2 0.786±0.001cd 0.823±0.009a Comparative Example 3 0.830±0.013a 0.809±0.029a Example 1 0.835±0.013a 0.826±0.010a Example 2 0.790±0.015cd 0.804±0.018a Example 3 0.822±0.007ab 0.820±0.004a

[0157] As shown in Table 6, before inoculation with Ralstonia solanacearum, compared with the blank control and Comparative Example 1, the Fv / Fm value of tomato leaves was significantly increased after adding the modified biochar of Example 1. There were no significant changes in Example 2 compared with Comparative Example 2, and Example 3 compared with Comparative Example 3.

[0158] After inoculation with Ralstonia solanacearum, compared with the blank control and Comparative Example 1, the Fv / Fm value of tomato leaves was significantly increased after the addition of modified biochar from Example 1. There were no significant changes in Example 2 compared with Comparative Example 2, and in Example 3 compared with Comparative Example 3.

[0159] The results of this experiment show that applying modified biochar can increase the chlorophyll fluorescence content of plants, which is beneficial to plant growth. Among them, the modified biochar in Example 1 has the best effect.

[0160] 3. Fresh weight of the plant

[0161] Plant fresh weight of fruit as Figure 11 As shown, from Figure 11 It can be seen that, before inoculation with Ralstonia solanacearum, the fresh weight of tomato plants in Comparative Example 1 and Example 2 was significantly increased compared with the blank control, while the other comparative examples and examples had no significant effect.

[0162] After inoculation with Ralstonia solanacearum, the fresh weight of tomato plants in both the control and example samples increased significantly compared with the blank control. Furthermore, the fresh weight of the example samples was significantly higher than that of the control samples when cooked at the same temperature. The fresh weight of Example 1 reached the maximum value of 22.69g.

[0163] The results of this experiment show that applying modified biochar can increase the fresh weight of plants, enhance plant resistance, and promote plant growth. Among them, the modified biochar in Example 1 has the best effect.

[0164] 4. Soil pH value

[0165] Soil pH results as follows Figure 12 As shown, from Figure 12 It can be seen that, before and after inoculation with Ralstonia solanacearum, compared with the blank control and comparative examples 1-3, Examples 1-3 all significantly increased the soil pH. Since bacterial wilt is prone to occur in acidic soils, the increase in pH improved the soil acidity and was beneficial to inhibiting the occurrence of bacterial wilt.

[0166] 5. Soil EC

[0167] Soil EC results as follows Figure 13 As shown, from Figure 13 It can be seen that, after inoculation with Ralstonia solanacearum, compared with biochar treatment at the same temperature, Example 1 showed the most significant increase in effect, and this effect was within the range suitable for plant growth.

[0168] 6. Available silicon content in soil

[0169] Soil available silicon content results as follows Figure 14 As shown, from Figure 14It can be seen that, before and after inoculation with Ralstonia solanacearum, compared with the blank control and comparative examples 1-3, Examples 1-3 significantly increased the available silicon content in the soil, thereby enhancing the plant's disease resistance.

[0170] 7. Soil C / N

[0171] Soil C / N results as follows Figure 15 As shown, from Figure 15 It can be seen that, before and after inoculation with Ralstonia solanacearum, compared with the blank control and comparative examples 1-3, all examples 1-3 significantly increased the soil C / N ratio, and after inoculation, the soil C / N ratio of example 1 showed the most significant increase.

[0172] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0173] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preventing and controlling bacterial wilt in vegetables, characterized in that, Includes the following steps: Modified biochar was used as a base fertilizer for vegetables. The modified biochar was Canadian goldenrod modified with sodium silicate solution. The modified biochar is prepared by the following method: Canadian goldenrod powder is placed in a sodium silicate solution, stirred, centrifuged, dried, and then pyrolyzed and carbonized under oxygen-limited or oxygen-deficient conditions; the pyrolysis and carbonization temperature is 450℃~650℃. The mass concentration of the sodium silicate solution is 5% to 15%; the mass-to-volume ratio of Canadian goldenrod to sodium silicate solution is 1:12 to 18.

2. The method according to claim 1, characterized in that, The heating rate of the pyrolysis carbonization is 5℃ / min to 10℃ / min.

3. The method according to claim 1, characterized in that, The pyrolysis carbonization time is 100 min to 140 min; and / or nitrogen protection is used during the pyrolysis carbonization, and the flow rate of the nitrogen is 2 ml / min to 3 ml / min.

4. The method according to claim 1, characterized in that, The stirring temperature is 28℃~32℃, the stirring speed is 120 r / min~180 r / min, and the stirring time is 150 min~200 min.

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