A method for reducing pseudomonas and fusarium in soil and its application

Abstract

This invention discloses a technology and its application for effectively reducing the growth of *Ralstonia solanacearum* and *Fusarium oxysporum* in soil, belonging to the field of soil remediation technology. It innovatively uses calcium peroxide as the main component, leveraging its strong oxidizing properties to rapidly increase the redox potential in the soil to be remediated, achieving efficient and rapid reduction of *Ralstonia solanacearum* and *Fusarium oxysporum*, while also improving acidic soil. Compared to other oxidants and fungicides, calcium peroxide has stronger oxidizing power and higher reduction efficiency. Then, organic materials containing beneficial microorganisms are applied to the soil to be remediated at a certain mass ratio to facilitate timely replenishment of soil organic matter and continuously inhibit the proliferation of the aforementioned pathogens. This invention's unique combined remediation technology can significantly reduce the incidence of soil-borne diseases caused by *Ralstonia solanacearum* and *Fusarium oxysporum*, while promoting crop growth and development. This invention has advantages such as low operational requirements, high reduction efficiency, and effective remediation of continuous cropping obstacles, and has high practical value and application prospects.

Description

Technical Field

[0001] This invention relates to the field of soil remediation technology, and in particular to a method for effectively reducing the growth of Ralstonia solanacearum and Fusarium oxysporum in soil and its application. Background Technology

[0002] The planting area of ​​crops in my country has been increasing year by year, and the agricultural industrial structure is also undergoing continuous adjustments. Due to factors such as intensive greenhouse cultivation, high multiple cropping index, and single crop variety, the phenomenon of continuous cropping obstacles is becoming increasingly prominent. To date, commonly used technologies for controlling soil continuous cropping obstacles have not achieved good overall results.

[0003] Excessive proliferation of *Ralstonia solanacearum* and *Fusarium oxysporum* in the soil increases their chances of causing diseases, leading to epidemics, harming crops, disrupting the soil's ecological balance, affecting the stability and health of the soil ecosystem, and infecting plant roots, reducing the plant's ability to absorb nutrients and severely hindering growth. Therefore, the occurrence of *Ralstonia solanacearum* and *Fusarium oxysporum* seriously affects crop yield and quality, causing significant economic losses. There is an urgent need to provide a method that is highly efficient in killing *Ralstonia solanacearum* and *Fusarium oxysporum* in the soil and can improve acidified soil. Summary of the Invention

[0004] Calcium peroxide (CaO2) is an odorless, tasteless, and non-toxic alkaline compound, appearing as a white or yellow powder. It is non-explosive and extremely stable when dry. It reacts with water to produce oxygen and alkaline inorganic substances, releasing heat. The effects of calcium peroxide are twofold: firstly, its strong oxidizing properties, when applied to the soil, trigger a vigorous redox reaction, oxidizing reduced substances in the soil, reducing the accumulation of reduced substances, increasing the soil's redox potential, and improving redox conditions, thereby killing soil-borne pathogens. Secondly, calcium peroxide can effectively regulate soil pH, addressing problems such as soil acidification and the instability and rapid consumption of oxidants in the soil. (Common oxidants such as hydrogen peroxide or persulfate are usually used with iron, which forms hydroxyl radicals (E0 = 2.8V). Strict acidic conditions are required to prevent iron precipitation, which can lead to soil acidification, reduce the activation effectiveness of iron, and result in low utilization efficiency of the oxidant.)

[0005] This invention pioneers a combined remediation technology, utilizing the strong oxidizing properties of calcium peroxide to reduce soil-borne disease pathogens while simultaneously applying organic materials to replenish soil organic matter. Using tomatoes and watermelons as materials, a calcium peroxide-organic material system was employed to remediate continuous cropping obstacles in the soil. The optimal mass fraction of calcium peroxide was investigated, and the disease incidence of crops under different treatments with calcium peroxide and various types of organic materials was further studied. This combined remediation technology overcomes the shortcomings of traditional fungicides, such as excessive byproducts, low remediation efficiency, and significant impact on soil nutrients. It is hoped that this technology can provide a reference for ecological agriculture production and offer concrete practical significance for improving soil-borne diseases and soil acidification caused by long-term continuous cropping.

[0006] This invention is achieved through the following technical solution:

[0007] The first objective of this invention is to provide a sterilizing agent for reducing Ralstonia solanacearum and Fusarium oxysporum in soil, the sterilizing agent comprising the following raw materials in parts by weight: calcium peroxide 10g / kg to 40g / kg.

[0008] Furthermore, the sterilizing agent comprises the following raw materials in parts by weight: calcium peroxide 30g / kg.

[0009] A second objective of this invention is to provide a composition for reducing Ralstonia solanacearum and Fusarium oxysporum in soil, the composition comprising the aforementioned sterilizing agent for Ralstonia solanacearum and Fusarium oxysporum in soil and 9 g / kg of organic fertilizer.

[0010] Furthermore, the organic fertilizer is an organic fertilizer containing beneficial microorganisms.

[0011] Furthermore, the beneficial microorganism is Trichoderma harzianum NJAU4742 with accession number CGMCC No.12166.

[0012] Furthermore, the concentration of Trichoderma harzianum NJAU4742 spores in the bio-organic fertilizer is 5 × 10⁻⁶. 7 CFU g -1 .

[0013] Furthermore, the organic fertilizer contains 45% organic matter.

[0014] A third objective of this invention is to provide the application of calcium peroxide or the aforementioned sterilizing agents for Ralstonia solanacearum and Fusarium oxysporum in soil in reducing Ralstonia solanacearum and Fusarium oxysporum in soil and / or adjusting soil pH.

[0015] Furthermore, calcium peroxide or the aforementioned sterilizing agents for Ralstonia solanacearum and Fusarium oxysporum in the soil can be directly mixed and applied with the soil.

[0016] A fourth object of the present invention is to provide the application of the aforementioned composition for reducing Ralstonia solanacearum and Fusarium oxysporum in soil in reducing Ralstonia solanacearum and Fusarium oxysporum and / or adjusting soil pH.

[0017] Furthermore, the composition for reducing Ralstonia solanacearum and Fusarium oxysporum in the soil is mixed with the soil and applied.

[0018] Furthermore, calcium peroxide and organic fertilizer can be applied simultaneously in the composition for reducing Ralstonia solanacearum and Fusarium oxysporum in the soil, or calcium peroxide in the composition for reducing Ralstonia solanacearum and Fusarium oxysporum in the soil can be applied one month before transplanting or sowing, and organic fertilizer can be applied one week before transplanting or sowing.

[0019] The beneficial effects of this invention are as follows:

[0020] 1) This invention is the first to use calcium peroxide as the main component, utilizing its strong oxidizing properties to rapidly increase the oxidation-reduction potential, thereby achieving a highly efficient and rapid effect in killing soil-borne pathogenic microorganisms. Compared with other oxidants and fungicides, it has stronger oxidizing properties and higher reduction efficiency.

[0021] 2) This invention is the first to utilize the property of calcium peroxide to effectively regulate soil pH, thereby improving acidified soil and regulating the soil microbial community structure.

[0022] 3) This invention adopts a combined remediation technology, which effectively kills soil-borne pathogenic microorganisms while replenishing soil organic matter content in a timely manner, which is beneficial to crop growth and development.

[0023] 4) When the product of this invention is used before transplanting, the number of Ralstonia solanacearum and Fusarium oxysporum in the soil is reduced by more than two orders of magnitude, and the incidence of crop diseases can be significantly reduced.

[0024] 5) The fertilizer composition for reducing Ralstonia solanacearum and Fusarium oxysporum in soil described in this invention can rapidly reduce the number of these pathogens in the soil, thereby inhibiting their growth and invasion, and reducing the incidence of plant diseases. This combined reduction method and application has the advantages of being easy to use, low in cost, and having good disease prevention effects, making it suitable for large-scale use in the cultivation of economic crops such as fruits, vegetables, and flowers. The application of this invention is of great significance for ensuring the sustainable development of facility agriculture, reducing the input of pesticides and other chemicals, protecting the ecological environment, and improving the quality of agricultural products. Attached Figure Description

[0025] Figure 1 The inhibitory effects of different concentrations of calcium peroxide on Ralstonia solanacearum;

[0026] Figure 2 The inhibitory effects of different concentrations of calcium peroxide on Fusarium oxysporum;

[0027] Figure 3 The effect of adding calcium peroxide on soil organic matter content;

[0028] Figure 4 The effect of adding calcium peroxide on soil pH;

[0029] Figure 5 The incidence rate and trend of watermelon disease;

[0030] Figure 6 The effects of calcium peroxide and beneficial microorganisms on total bacteria and Fusarium oxysporum in the soil.

[0031] Figure 7 The incidence rate and trend of tomato diseases;

[0032] Figure 8 The effects of calcium peroxide and organic fertilizers containing beneficial microorganisms on total bacteria and Ralstonia solanacearum in soil. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments, but the scope of protection is not limited thereto. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0034] Example 1: Optimization Experiment of Calcium Peroxide Concentration for Reducing Ralstonia solanacearum

[0035] Test methods

[0036] The number of Ralstonia solanacearum was determined by the dilution plating method. The culture medium was K2 selective medium, and the culture was carried out at 28℃ for 72 h. Representative air-dried soil samples were selected. Soil was divided into 9 portions, each weighing 10 g, and placed in disposable petri dishes. 1 ml of Ralstonia solanacearum inoculum was added to each portion sequentially. Water was then added to each portion sequentially to maintain the soil moisture content above 80%. Finally, 3% (M:M) of calcium peroxide by soil mass was added sequentially. Each treatment was replicated in triplicate.

[0037] (1) Treatment without calcium peroxide, with all other components the same as in the above examples (CK);

[0038] (2) Add 1% calcium peroxide by weight of the soil; this treatment is recorded as 1%;

[0039] (3) Add 2% calcium peroxide by the mass of the soil; this treatment is recorded as 2%;

[0040] (4) Add 3% calcium peroxide by weight of the soil; this treatment is recorded as 3%;

[0041] (5) Add 4% calcium peroxide by weight of the soil; this treatment is recorded as 4%.

[0042] Comparison results

[0043] Depend on Figure 1 It was found that after the addition of calcium peroxide, the number of *Ralstonia solanacearum* in the soil decreased to varying degrees in all treatment groups compared with the control group. Specifically, the bacterial count reduction rates in the 1%, 2%, 3%, and 4% treatment groups were 94.5%, 96.7%, 97.8%, and 97.6% lower than those in the control group, respectively. The optimal concentration was 3%. Different letters indicate significant differences between treatments (P<0.05).

[0044] Experiment Example 2: Optimization Experiment for Reducing Calcium Peroxide Concentration in Fusarium oxysporum

[0045] Test methods

[0046] The number of *Fusarium oxysporum* was determined by the dilution plating method. The culture medium was NA selective medium, and the culture was carried out at 28℃ for 72 h. Representative air-dried soil samples were selected. Soil was divided into 9 portions, each weighing 10 g, and placed in disposable petri dishes. 1 ml of *Fusarium oxysporum* inoculum was added to each portion sequentially. Water was then added to each portion sequentially to maintain a soil moisture content above 80%. Finally, 3% (M:M) of calcium peroxide by soil mass was added sequentially. Each treatment was replicated in triplicate.

[0047] (1) Treatment without calcium peroxide, with all other components the same as in the above examples (CK);

[0048] (2) Add 1% calcium peroxide by weight of the soil; this treatment is recorded as 1%;

[0049] (3) Add 2% calcium peroxide by the mass of the soil; this treatment is recorded as 2%;

[0050] (4) Add 3% calcium peroxide by mass of soil; this treatment is recorded as 3%.

[0051] (5) Add 4% calcium peroxide by weight of the soil; this treatment is recorded as 4%.

[0052] Comparison results

[0053] Depend on Figure 2 It can be seen that after the addition of calcium peroxide, the number of Fusarium oxysporum in the soil decreased to varying degrees in each treatment group compared with the control group. Specifically, the reduction rates of bacteria count in the 1%, 2%, 3%, and 4% treatment groups were 87.2%, 96.7%, 98.2%, and 98.33% lower than those in the control group, respectively. The preferred calcium peroxide concentration remained at 3%. Different letters indicate significant differences between treatments (P<0.05). Example 3: Effects of different concentrations of calcium peroxide on soil organic matter.

[0054] Test methods

[0055] Three soil samples with different organic matter contents (CK, CK+1% SOM, CK+2% SOM) were weighed into test tubes, 10g each. The first sample (control group) was not treated with calcium peroxide. For the remaining samples, calcium peroxide at concentrations of 1%, 2%, 3%, and 4% was added sequentially. After thorough mixing, 8mL of sterile water was added. Each group was tested in triplicate. The samples were covered with plastic wrap to prevent moisture evaporation. Appropriate amounts of sample were weighed into test tubes, and three blank controls were set up. Each material was tested in three replicates using an oil bath.

[0056] (1) Treatment without calcium peroxide, with all other components the same as in the above examples (CK);

[0057] (2) Add 1% calcium peroxide by weight of the soil; this treatment is recorded as 1%;

[0058] (3) Add 2% calcium peroxide by the mass of the soil; this treatment is recorded as 2%;

[0059] (4) Add 3% calcium peroxide by mass of soil; this treatment is recorded as 3%.

[0060] (5) Add 4% calcium peroxide by weight of the soil; this treatment is recorded as 4%.

[0061] Comparison results

[0062] Depend on Figure 3 It was found that after adding calcium peroxide, the organic matter content in the soil decreased to varying degrees compared with the control group in each treatment group. Specifically, the organic matter content in the 1%, 2%, 3%, and 4% treatment groups decreased by 3.6%, 5.7%, 8.9%, and 22.6% respectively compared with the control group. This indicates that when the calcium peroxide concentration is increased to 4%, the organic matter content in the soil shows a significant decreasing trend. Consistent with the above optimization experiment results, the optimal calcium peroxide concentration is 3% (30 g / kg). Therefore, when using calcium peroxide for sterilization, it is necessary to apply a certain amount of organic fertilizer to the soil in a timely manner to replenish soil organic matter and ensure crop growth and development. Different letters indicate significant differences between treatments (P<0.05).

[0063] Example 4

[0064] Experimental methods

[0065] Soil samples were divided into five aliquots, each weighing 10g (dry weight), placed in disposable plates. The first aliquot did not contain calcium peroxide (blank control group). The remaining four aliquots were treated with calcium peroxide at concentrations of 1%, 2%, 3%, and 4%, respectively. After thorough mixing, 8mL of sterile water was added, and the plates were covered with plastic wrap to prevent evaporation. Each group was replicated in triplicate. Soil samples were collected one day later, and the soil pH was determined using a soil-to-water ratio of 1:5.

[0066] (1) Treatment without calcium peroxide, with all other components the same as in the above examples (CK);

[0067] (2) Add 1% calcium peroxide by weight of the soil; this treatment is recorded as 1%;

[0068] (3) Add 2% calcium peroxide by the mass of the soil; this treatment is recorded as 2%;

[0069] (4) Add 3% calcium peroxide by mass of soil; this treatment is recorded as 3%.

[0070] (5) Add 4% calcium peroxide by weight of the soil; this treatment is recorded as 4%.

[0071] Comparison results

[0072] Depend on Figure 4 It was found that the soil pH value of the blank control group generally showed a trend of first increasing and then continuously decreasing, reaching a maximum of 5.93 on day 10, and then gradually decreasing. In the treatment groups with added calcium peroxide, the trend of change in the low addition treatment (1%) was the same as that in the blank control, but its pH value was higher than that of the control at all time points; the maximum pH value of the soil in the other treatment groups appeared on day 5, and then continuously decreased with the extension of the incubation time. The pH value at each time point increased with the increase of the amount of calcium peroxide added, and was higher than that of the control. The calcium hydroxide generated by the reaction of calcium peroxide with soil moisture can increase the soil pH. After the addition of calcium peroxide, the soil pH value was significantly higher than that of the control. When the addition amount was 1%, the change pattern of soil pH was the same as that without the addition of calcium peroxide; when the addition amount increased, the soil pH rapidly increased to the maximum value on day 1, and then continued to decrease, and the decrease was significant. The pH of the treatment group with 4% calcium peroxide added was still high on day 30, reaching 8.95, while crops generally have difficulty absorbing the mineral elements required for growth when the pH exceeds 8.0. This can negatively impact the normal growth and development of crops. Different letters indicate significant differences between treatments (P<0.05).

[0073] Example 5

[0074] The calcium peroxide used in this experiment was 30 g / kg.

[0075] Preparation: The effective viable count of Fusarium oxysporum in the soil is 2 × 10⁻⁶. 6 CFU / g. The effective viable count of Ralstonia solanacearum in the soil is 2 × 10⁻⁶. 8CFU / g. Six replicates were set up for each treatment. (48-well seedling trays were used, with 80g of soil per cell and 5kg of soil prepared per tray. Every 8 cells constituted one replicate). Each tray contained 5kg of soil, with the water content controlled at approximately 40%. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 5 days, 0% and 3% calcium peroxide were added respectively for monitoring, and no water was added during this time.

[0076] Use: Watermelon seedlings and tomato seedlings are scheduled to be transplanted on October 18, 2022. Use before transplanting.

[0077] Example 6

[0078] The organic fertilizer used in this experiment was 9 g / kg. (Straw-derived organic fertilizer: organic matter content >45%)

[0079] Preparation: The effective viable count of Fusarium oxysporum in the soil is 2 × 10⁻⁶. 6 CFU / g. The effective viable count of Ralstonia solanacearum in the soil is 2 × 10⁻⁶. 8 CFU / g. Six replicates were set up for each treatment. (48-well seedling trays were used, with 80g of soil per cell and 5kg of soil prepared per tray. Every 8 cells constituted one replicate). Each tray contained 5kg of soil, with the water content controlled at approximately 40%. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 5 days, 0% and 3% calcium peroxide were added respectively, and no water was added during monitoring. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 7 days, 0.9% organic fertilizer was added to each tray to continue monitoring the recovery of total bacteria.

[0080] Use: Watermelon seedlings and tomato seedlings are scheduled to be transplanted on October 18, 2022. Use before transplanting.

[0081] Example 7

[0082] The amount of calcium peroxide used in this experiment was 30 g / kg, and the amount of organic fertilizer was 9 g / kg (straw-derived organic fertilizer: organic matter content >45%).

[0083] Configuration: The effective viable count of Fusarium oxysporum in the soil is 2 × 10⁻⁶. 6 CFU / g. The effective viable count of Ralstonia solanacearum in the soil is 2 × 10⁻⁶. 8CFU / g. Six replicates were set up for each treatment. (48-well seedling trays were used, with 80g of soil per cell, and 5kg of soil prepared per tray. Every 8 cells constituted one replicate). Each tray contained 5kg of soil, with the water content controlled at approximately 40%. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 5 days, 0% and 3% calcium peroxide were added respectively, without adding water during monitoring. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 7 days, 0.9% organic fertilizer was added to each tray to continue monitoring the recovery of total bacteria.

[0084] Use: Watermelon seedlings and tomato seedlings are scheduled to be transplanted on October 18, 2022. Use before transplanting.

[0085] Example 8

[0086] The organic fertilizer containing beneficial microorganisms described in this experiment is 9 g / kg, and the beneficial microorganism is Trichoderma harzianum NJAU4742 (accession number: CGMCC No.12166).

[0087] Preparation: The effective viable count of Fusarium oxysporum in the soil is 2 × 10⁻⁶. 6 CFU / g. The effective viable count of Ralstonia solanacearum in the soil is 2 × 10⁻⁶. 8 CFU / g. Six replicates were set up for each treatment. (48-well seedling trays were used, with 80g of soil per cell, and 5kg of soil prepared per tray. Every 8 cells constituted one replicate). Each tray contained 5kg of soil, with the water content controlled at approximately 40%. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 5 days, 0% and 3% calcium peroxide were added respectively, and no water was added during monitoring. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 7 days, 0.9% of organic fertilizer containing beneficial microorganisms was added to each tray to continue monitoring the recovery of total bacteria.

[0088] Use: Watermelon seedlings and tomato seedlings are scheduled to be transplanted on October 18, 2022. Use before transplanting.

[0089] Example 9

[0090] The calcium peroxide used in this experiment was 30 g / kg, the organic fertilizer containing beneficial microorganisms was 9 g / kg, and the beneficial microorganism was Trichoderma harzianum NJAU4742 (accession number: CGMCC No.12166).

[0091] Preparation: The effective viable count of Fusarium oxysporum in the soil is 2 × 10⁻⁶. 6 CFU / g. The effective viable count of Ralstonia solanacearum in the soil is 2 × 10⁻⁶. 8CFU / g. Six replicates were set up for each treatment. (48-well seedling trays were used, with 80g of soil per cell, and 5kg of soil prepared per tray. Every 8 cells constituted one replicate). Each tray contained 5kg of soil, with the water content controlled at approximately 40%. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 5 days, 0% and 3% calcium peroxide were added respectively, and no water was added during monitoring. After 3 days, 100ml of bacterial solution was added to each tray to monitor the counts of Fusarium oxysporum and Ralstonia solanacearum. After 7 days, 0.9% of organic fertilizer containing beneficial microorganisms was added to each tray to continue monitoring the recovery of total bacteria.

[0092] Use: Watermelon seedlings and tomato seedlings are scheduled to be transplanted on October 18, 2022. Use before transplanting.

[0093] Experimental Example 10

[0094] Test plants

[0095] Watermelon potted experimental variety: "Lenong No. 3".

[0096] Test methods

[0097] Sowing was carried out at this experimental site on October 18, 2022. The experiment included a blank control (CK) group and two groups treated with a combination of different fertilizers and calcium peroxide:

[0098] (1) Treatment without calcium peroxide, with all other components the same as in the above examples (CK);

[0099] (2) Calcium peroxide in Example 5 of the present invention; this treatment is denoted as CK 3%;

[0100] (3) The treatment of adding only organic fertilizer in Example 6 of the present invention; this treatment is denoted as Y 0%.

[0101] (4) The combination of calcium peroxide and organic fertilizer in Example 7 of the present invention; this treatment is denoted as Y 3%;

[0102] (5) Example 8 of the present invention only adds organic fertilizer containing beneficial microorganisms; this treatment is denoted as V 0%.

[0103] (6) The combination of calcium peroxide and organic fertilizer containing beneficial microorganisms in Example 9 of the present invention; this treatment is denoted as V 3%; each treatment is set up with 6 replicates, and each replicate consists of 8 plants.

[0104] Comparison results

[0105] Depend on Figure 5It was found that all treatment groups showed significant differences compared to the control group, and the incidence rate decreased in all groups. The incidence rate in the control group was 68%, while the incidence rates in the treatment groups (CK3%, Y3%, and V3%) were 40%, 29.6%, and 20%, respectively, representing decreases of 28%, 37.4%, and 48% compared to the control. There were no significant differences in incidence rates among the treatment groups, but all were significantly lower than the control. This indicates that the addition of high concentrations of calcium peroxide significantly inhibited the incidence rate of watermelon, reducing the overall disease trend. The highest incidence rate was observed in the CK treatment (68%), and the lowest was observed in the treatment combining calcium peroxide with Trichoderma-containing organic fertilizer (20%). Compared to the treatments using calcium peroxide alone (CK), organic fertilizer alone (Y0%), and Trichoderma-containing bio-organic fertilizer alone (V0%), the incidence rates in the treatments combining calcium peroxide with organic fertilizer (Y3%) and calcium peroxide with Trichoderma-containing bio-organic fertilizer (V3%) were significantly lower, decreasing by 10.4% and 20%, 22.4% and 30%, and 15.4% and 25%, respectively. Studies have shown that *Trichoderma harzianum* mainly inhibits the growth and reproduction of target soil-borne pathogens through mechanisms such as competition, induction of host resistance, hyperparasitism, and antibiotic activity. The results of this embodiment show that the combined treatment of calcium peroxide and *Trichoderma harzianum*-containing organic fertilizer significantly outperformed the treatments using calcium peroxide alone, organic fertilizer alone, and *Trichoderma harzianum*-containing bio-organic fertilizer alone. The two treatments exhibited a synergistic antibacterial effect, ultimately reducing the incidence rate by 48% compared to the control group, with a control rate reaching 70.5%. Different letters indicate significant differences between treatments (P<0.05). Figure 6 It was found that, 28 days after sowing, the total bacterial count and *Fusarium oxysporum* count in the soil were significantly higher in the treatment with calcium peroxide followed by *Trichoderma*-containing organic fertilizer than in the control treatment; the *Fusarium oxysporum* count was significantly lower in the treatment with calcium peroxide followed by organic fertilizer containing *Trichoderma*. Different letters indicate significant differences between treatments (P<0.05).

[0106] Experimental Example 11

[0107] Test plants

[0108] Tomato pot experiment variety: "Micro Tom".

[0109] Test methods

[0110] Sowing was carried out at this experimental site on October 18, 2022. The experiment included a blank control (CK) group and three groups treated with a combination of different fertilizers and calcium peroxide:

[0111] (1) Treatment without calcium peroxide, with all other components the same as in the above examples (CK);

[0112] (2) Calcium peroxide in Example 5 of the present invention; this treatment is denoted as CK 3%;

[0113] (3) The treatment of adding only organic fertilizer in Example 6 of the present invention; this treatment is denoted as Y 0%.

[0114] (4) The combination of calcium peroxide and organic fertilizer in Example 7 of the present invention; this treatment is denoted as Y 3%;

[0115] (5) Example 8 of the present invention only adds organic fertilizer containing beneficial microorganisms; this treatment is denoted as V 0%.

[0116] (6) The combination of calcium peroxide and organic fertilizer containing beneficial microorganisms in Example 9 of the present invention; this treatment is denoted as V 3%; each treatment is set up with 6 replicates, and each replicate consists of 8 plants.

[0117] Depend on Figure 7 It was found that all treatment groups showed significant differences compared to the control group, and the incidence rates decreased in all groups. The incidence rate in the control group was 62%, while the incidence rates in the treatment groups (CK3%, Y3%, and V3%) were 43%, 28.6%, and 14%, respectively, representing decreases of 19%, 33.4%, and 48% compared to the control. There were no significant differences in incidence rates among the treatment groups, but all were significantly lower than the control. This indicates that the addition of high concentrations of calcium peroxide significantly inhibited the incidence rate of tomatoes and reduced the overall incidence trend in watermelons. The highest incidence rate was observed in the CK treatment (62%), and the lowest was observed in the treatment combining calcium peroxide with Trichoderma-containing organic fertilizer (14%). Compared to the treatments using calcium peroxide alone (CK), organic fertilizer alone (Y0%), and Trichoderma-containing bio-organic fertilizer alone (V0%), the incidence rates in the treatments combining calcium peroxide with organic fertilizer (Y3%) and calcium peroxide with Trichoderma-containing bio-organic fertilizer (V3%) were significantly lower, decreasing by 15.4% and 21%, 21.4% and 32%, and 16.4% and 27%, respectively. Studies have shown that *Trichoderma harzianum* mainly inhibits the growth and reproduction of target soil-borne pathogens through mechanisms such as competition, induction of host resistance, hyperparasitism, and antibiotic activity. The results of this embodiment show that the combined treatment of calcium peroxide and *Trichoderma harzianum*-containing organic fertilizer significantly outperformed the treatments using calcium peroxide alone, organic fertilizer alone, and *Trichoderma harzianum*-containing bio-organic fertilizer alone. The two treatments exhibited a synergistic antibacterial effect, ultimately reducing the incidence rate by 48% compared to the control group. Different letters indicate significant differences between treatments (P<0.05).

[0118] Depend on Figure 8 It was found that, when the total number of bacteria and Ralstonia solanacearum in the soil were measured 28 days after sowing, the total number of bacteria in the treatment with added calcium peroxide followed by organic fertilizer containing Trichoderma was significantly higher than that in the control treatment; the number of Ralstonia solanacearum was significantly lower than that in the blank control treatment. Different letters indicate significant differences between treatments (P<0.05).

[0119] Based on the above efficacy experiments, the method of the present invention has a significant reduction effect on Ralstonia solanacearum and Fusarium oxysporum, and the combination with organic materials containing beneficial microorganisms can effectively inhibit the incidence of bacterial wilt in tomatoes and Fusarium wilt in watermelons, and is beneficial to crop growth and development.

[0120] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composition for reducing *Ralstonia solanacearum* and *Fusarium oxysporum* in soil, characterized in that, The composition comprises a sterilizing agent for Ralstonia solanacearum and Fusarium oxysporum in soil and 9 g / kg of organic fertilizer. The sterilizing agent comprises the following raw materials in the following weight proportions: calcium peroxide 10 g / kg to 40 g / kg; the organic fertilizer is an organic fertilizer containing beneficial microorganisms; the beneficial microorganism is Trichoderma harzianum NJAU4742 with accession number CGMCC No.12166.

2. The composition for reducing *Ralstonia solanacearum* and *Fusarium oxysporum* in soil according to claim 1, characterized in that, The spore concentration of Trichoderma harzianum NJAU4742 was 5 × 10⁻⁶. 7 CFU g -1 .

3. The composition for reducing *Ralstonia solanacearum* and *Fusarium oxysporum* in soil according to claim 1 or 2, characterized in that, The organic fertilizer contains 45% organic matter.

4. The use of the composition of claim 1 or 2 for reducing Ralstonia solanacearum and Fusarium oxysporum in soil in reducing Ralstonia solanacearum and Fusarium oxysporum and / or adjusting soil pH.

5. The application according to claim 4, characterized in that, The composition for reducing Ralstonia solanacearum and Fusarium oxysporum in the soil is mixed with the soil and applied.

6. The application according to claim 4, characterized in that, Apply calcium peroxide and organic fertilizer simultaneously to the composition for reducing Ralstonia solanacearum and Fusarium oxysporum in the soil, or apply calcium peroxide to the composition for reducing Ralstonia solanacearum and Fusarium oxysporum in the soil one month before transplanting or sowing, and apply organic fertilizer one week before transplanting or sowing.

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