Soil remediation fungicide as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of microbial fermentation and biological agriculture, and discloses a soil remediation fungicide as well as a preparation method and application thereof. The preparation method comprises the following steps: activating bacillus megatherium Z101, inoculating the activated bacillus megatherium Z101 into fermentation liquor containing rice straw powder, carrying out fermentation culture, and carrying out vacuum spray drying on fermentation mixed liquor after fermentation is completed, so as to obtain soil remediation bacterium powder; or further mixing the soil remediation bacterium powder with auxiliary materials and water, and granulating to obtain the soil remediation bacterium granules. The application method comprises the following steps: in a rice planting stage, applying the soil remediation fungicide and an inorganic fertilizer together to remedy rice field soil and promote rice growth. The soil remediation fungicide prepared by fermentation culture of the bacillus megatherium Z101 has remarkable advantages in the aspects of rice yield increase, soil pH value increase and physicochemical property improvement, and a new application way is provided for the bacillus megatherium Z101.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbial fermentation and bio-agriculture, and specifically relates to a soil remediation bacterial agent and a preparation method and application thereof. Background Art

[0002] Rice is one of my country's most important staple crops, and its cultivation relies on a healthy soil environment. Declining soil quality is a common factor in rice production, often leading to yield losses. Causes of soil degradation include soil erosion, over-cultivation, and insufficient fertility. Reducing soil acidification and improving soil physical and chemical properties (such as increasing organic matter, alkaline-hydrolyzable nitrogen, available phosphorus, and readily available potassium, while also reducing soil bulk density and increasing porosity) can promote increased rice yield and quality.

[0003] Bacillus megaterium, an important phosphate-solubilizing bacterium, is widely used in agricultural production. Optimizing its cultivation to produce microbial fertilizers can improve soil fertility and increase yields. However, current microbial fertilizers typically combine Bacillus megaterium with other bacterial species to create composite inoculants, and the effects of Bacillus megaterium alone are generally limited. Currently, the use of Bacillus megaterium as a soil remediation agent primarily focuses on remediating heavy metals in soil and preventing soil diseases and insecticides (e.g., patents with publication numbers CN 110628659 B and CN117535168B). Few reports exist on Bacillus megaterium fermentation cultures that demonstrate significant advantages in increasing rice yield, raising soil pH, and improving physical and chemical properties. Summary of the Invention

[0004] In order to promote rice yield and quality improvement, reduce paddy soil acidification and improve soil physical and chemical properties, the present invention aims to provide a soil remediation bacterial agent and its preparation method and application.

[0005] The purpose of the present invention is achieved through the following technical solutions: A method for preparing a soil remediation bacterial agent comprises the following steps: Bacillus megaterium is activated and inoculated into a fermentation liquid containing rice straw powder for fermentation and cultivation. After fermentation, the fermentation mixture is vacuum spray-dried to obtain a soil remediation bacterial powder; or the soil remediation bacterial powder is further mixed with auxiliary materials and water and granulated to obtain a soil remediation bacterial granule.

[0006] The Bacillus megaterium Z101 used in the present invention has been disclosed in Chinese patent application publication number CN111592997 A.

[0007] The classification name of the biological sample material involved in the present invention is: Bacillus megaterium; preservation date: December 9, 2019; preservation unit: Guangdong Provincial Microbiological Culture Collection Center-GDMCC; preservation number: GDMCC NO: 60928; preservation unit address: No. 58, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou City.

[0008] Preferably, the activation method is: inoculating the Bacillus megaterium Z101 strain into LB solid culture medium, and culturing at 30-37° C. for 24-36 hours to obtain the activated strain.

[0009] Preferably, the fermentation liquid containing rice straw powder comprises the following components: Rice straw powder 50-100g / L, glucose 5-15g / L, soybean cake powder 5-15g / L, yeast powder 0.5-2g / L, sodium glutamate 0.5-2g / L, ammonium sulfate 0.5-1g / L, urea 0.2-1g / L, dipotassium hydrogen phosphate 0.2-0.5 g / L, magnesium sulfate 0.01-0.05g / L, manganese sulfate monohydrate 0.005-0.01g / L.

[0010] Preferably, the inoculum size of the fermentation culture is 2-5%.

[0011] Preferably, during the fermentation process, the pH is controlled to be 7.0-7.5 by adding acid or alkaline solution.

[0012] Preferably, the fermentation culture temperature is controlled at 30-37°C and the fermentation time is 36-72 hours.

[0013] Preferably, the auxiliary material is one or more of starch, dextrin and sucrose.

[0014] A soil remediation bacterial agent is prepared by the above method; the soil remediation bacterial agent is a soil remediation bacterial powder or a soil remediation bacterial granule.

[0015] Preferably, the effective viable bacteria count of the soil remediation bacteria powder is ≥600 million / g, and the effective viable bacteria count of the soil remediation bacteria granules is ≥300 million / g.

[0016] The application of the above-mentioned soil remediation bacterial agent in paddy field soil remediation and rice cultivation.

[0017] Preferably, the application method is: during the rice planting stage, the soil remediation bacterial agent is applied together with inorganic fertilizer to repair the paddy field soil and promote rice growth.

[0018] More preferably, the inorganic fertilizer is a mixture of high-concentration compound fertilizer with a total nutrient content of ≥40%, urea and potassium chloride; the dosage of the soil remediation bacteria agent and the inorganic fertilizer is: 150~250kg / mu of soil remediation bacteria agent, 20~40kg / mu of high-concentration compound fertilizer, 5~15kg / mu of urea, and 3~8kg / mu of potassium chloride.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) The soil remediation bacterial agent of the present invention can promote the increase of rice yield and quality, reduce the acidification of paddy soil and improve the physical and chemical properties of soil (such as increasing organic matter, alkaline nitrogen, available phosphorus, and available potassium, reducing soil bulk density and increasing porosity, etc.).

[0020] (2) The soil remediation agent prepared by fermentation culture of Bacillus megaterium Z101 of the present invention has significant advantages in increasing rice yield, improving soil pH and improving physical and chemical properties compared with conventional Bacillus megaterium fermentation culture agents, providing a new application approach for Bacillus megaterium Z101. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto. Example 1

[0022] A method for preparing a soil remediation bacterial agent comprises the following steps: Bacillus megaterium Z101 (deposited in Guangdong Provincial Microbial Culture Collection Center on December 11, 2019, with the deposit number GDMCC NO: 60928) was inoculated into LB solid medium and cultured at 32-35°C for 30 h. The active mycelium was taken for bacterial examination and inoculated into the fermentation broth at 4 wt% for fermentation. The fermentation broth composition included: rice straw powder (80 mu particle size) 80 g / L, glucose 10 g / L, soybean cake powder 10 g / L, yeast powder 1 g / L, sodium glutamate 1 g / L, ammonium sulfate 0.6 g / L, urea 0.6 g / L, K2HPO4 0.4 g / L, magnesium sulfate 0.02 g / L, and manganese sulfate monohydrate 0.006 g / L. During the fermentation process, the pH was controlled within the range of 7.0-7.5 by adding acid and alkaline solutions, and the fermentation temperature was controlled at 32-35°C for 48 hours. The fermentation mixture was then vacuum spray-dried to produce a soil remediation agent (powder) with an effective viable cell count of 830 million / g. The resulting soil remediation agent (powder) was further mixed with corn starch, sucrose, and water in a mass ratio of 1:1:0.1:0.4, and granulated to produce a soil remediation agent (granules) with an effective viable cell count of 350 million / g. Example 2

[0023] A method for preparing a soil remediation bacterial agent comprises the following steps: Bacillus megaterium Z101 was inoculated into LB solid medium and cultured at 30-32°C for 24 hours. Active mycelium was then inoculated into a fermentation broth at a 5wt% concentration. The fermentation broth consisted of 100g / L rice straw powder (80-mu particle size), 5g / L glucose, 5g / L soybean meal powder, 2g / L yeast extract, 2g / L sodium glutamate, 1g / L ammonium sulfate, 1g / L urea, 0.5g / L K2HPO4, 0.02g / L magnesium sulfate, and 0.006g / L manganese sulfate monohydrate. During the fermentation process, the pH was controlled between 7.0 and 7.5 by adding acid and alkaline solutions. The fermentation temperature was maintained at 30-32°C for 72 hours. The fermentation mixture was then vacuum spray-dried to produce a soil remediation bacterial powder with an effective viable count of 900 million bacteria per gram. The obtained soil remediation bacteria powder was further mixed with corn starch and water in a mass ratio of 1:1.5:0.4 and then granulated to obtain soil remediation bacteria granules with an effective live bacteria count of 340 million / g. Example 3

[0024] A method for preparing a soil remediation bacterial agent comprises the following steps: Bacillus megaterium Z101 was inoculated into LB solid medium and cultured at 35-37°C for 36 hours. Active mycelium was then collected and inoculated into a fermentation broth at a rate of 2 wt%. The fermentation broth consisted of 50 g / L rice straw powder (80 mu particle size), 15 g / L glucose, 15 g / L soybean meal powder, 0.5 g / L yeast extract, 0.5 g / L sodium glutamate, 0.5 g / L ammonium sulfate, 0.2 g / L urea, 0.2 g / L K₂HPO₄, 0.02 g / L magnesium sulfate, and 0.006 g / L manganese sulfate monohydrate. During the fermentation process, the pH was controlled between 7.0 and 7.5 by adding acid and alkaline solutions. The fermentation temperature was maintained at 35-37°C for 36 hours. The fermentation mixture was then vacuum spray-dried to produce a soil remediation bacterial powder with an effective viable count of 680 million bacteria per gram. The obtained soil remediation bacteria powder was further mixed with corn starch, dextrin and water in a mass ratio of 1:0.5:0.1:0.3 and then granulated to obtain soil remediation bacteria granules with an effective live bacteria count of 320 million / g.

[0025] Comparative Example 1 A method for preparing a soil remediation bacterial agent comprises the following steps: Commercially available Bacillus megaterium (Sanggong Bio) was activated and fermented using the same method as in Example 1. After vacuum spray drying, a soil remediation agent (powder) with an effective viable count of 850 million cells / g was obtained. The resulting soil remediation agent (powder) was further mixed with corn starch, sucrose, and water in a mass ratio of 1:1:0.1:0.4, and granulated to obtain a soil remediation agent (granules) with an effective viable count of 360 million cells / g. Example 4

[0026] The application of the soil remediation bacterial agent obtained by the present invention (using the soil remediation bacterial agent of Example 1 as the test group) in paddy field soil remediation and rice cultivation, in accordance with the requirements of the "Fertilizer Registration Management Measures", "Fertilizer Registration Service Guide", "Soil Conditioner Effect Test and Evaluation Requirements" (NY / T 2271-2016) and "Microbial Fertilizer Field Test Technical Specifications and Fertilizer Efficacy Evaluation Guide" (NY / T 1536-2007), specifically includes the following steps: 1 Experimental materials and methods 1.1 Test time and location 1.1.1 Experimental period: Three growing seasons: March to July 2022, March to July 2023, and March to July 2024.

[0027] 1.1.2 Experimental location: Zheng Nengming's responsibility field, Pozai Village, Xinmin Village Committee, Bimian Town, Yangchun City, Guangdong Province.

[0028] 1.2 Test soil analysis The experimental plot had been continuously cultivated with rice for many years. Prior to the experiment, the land was renovated and no other crops were planted. Before tillage, soil from the topsoil layer was collected using an S-shaped, nine-point sampling method to a depth of 20 cm. The combined samples were then subjected to physical and chemical analysis (Table 1). The results showed that the soil in the experimental field was acidic, with moderate fertility and a pH of 5.23.

[0029] Table 1 Basic physical and chemical indicators of soil

[0030] 1.3 Test crops and varieties The test crop was rice, and the variety was the silk rice "Meixiangzhan No. 2".

[0031] 1.4 Experimental Design and Methods 1.4.1 Experimental Design The experimental design for the 2022, 2023, and 2024 early rice crops was the same, with six treatments (Table 2) in field plots. Each treatment was replicated three times, resulting in a total of 18 plots arranged in randomized blocks with a plot area of ​​20 m2. 2 .

[0032] Table 2 Experimental treatments

[0033] Note: The 40% compound fertilizer used is a common compound fertilizer with a total nitrogen content of 28%, an available phosphorus content of 6%, and an available potassium content of 6%. 1.4.2 Test methods 1.4.2.1 Field management Field management follows the principles of "optimum" and "consistency". Except for fertilization measures, all other management measures are consistent between treatments and meet production requirements. They are completed by dedicated personnel on the same day. After land preparation, soil remediation agents are applied according to the experimental design. The 2022 early rice experiment was sown on March 10, land preparation was carried out on April 10, transplanting was carried out on April 12, and harvesting was carried out on July 10; the 2023 early rice experiment was sown on March 11, land preparation was carried out on April 11, transplanting was carried out on April 12, and harvesting was carried out on July 11; the 2024 early rice experiment was sown on March 12, land preparation was carried out on April 10, transplanting was carried out on April 13, and harvesting was carried out on July 13; before harvesting, soil and rice samples from the cultivated layer of each plot in the experimental field were collected, and yield inspection and acceptance were carried out for each plot respectively, and multiple economic conditions of each treatment were examined and the actual yield was measured.

[0034] 1.4.2.2 Sample collection and preparation One day before harvest, rice plant and soil samples were collected from each plot. A five-point sampling method was used to sample evenly growing rice stems, ensuring that each replicate weighed approximately 500 g of dry rice. If the number of sampling stems was insufficient, additional sampling stems were used. The rice was then hulled and ground.

[0035] Soil samples were collected and prepared in accordance with NY / T1121.1-2006.

[0036] 1.4.2.3 Detection indicators and methods 1.4.2.3.1 Determination of main physical and chemical properties of soil Soil pH value was determined in accordance with NY / T1377-2007; soil organic matter was determined in accordance with NY / T1121.6-2006; soil total nitrogen was determined in accordance with NY / T1121.24-2006; soil alkaline nitrogen was determined using the alkaline diffusion method; soil available phosphorus was determined in accordance with NY / T1121.7-2006; soil available potassium was determined in accordance with NY / T1849-2010; soil bulk density and soil porosity were determined using the ring knife method.

[0037] 1.4.2.3.2 Observation of rice growth period Observe and record the growth and development of rice after sowing.

[0038] 1.4.2.3.3 Rice yield determination The yield is inspected at maturity. After the rice matures, each plot is harvested and dried separately. After removing impurities and chaff, the yield of each plot is converted according to the standard moisture content.

[0039] 1.4.2.3.4 Determination of major soil microbial populations After rice harvest, soil samples were collected from each plot using the same method as the basic soil samples. After mixing, they were placed in sterile plastic bags and brought back to the laboratory for storage at 4°C. 10 g of soil sample was weighed and placed in sterile water. The soil and water were shaken to mix thoroughly to obtain a 10- soil suspension. 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 Soil suspension. Bacteria selection 10 -4 , 10 -5 , 10 -6 The concentration gradient was determined by beef extract peptone plate culture; 10 -2 , 10 -3 , 10 -4 The three concentration gradients were tested by using Bengal red medium plate culture; 10 -3 , 10 -4 , 10 -5 Three concentration gradients were tested using Gao's medium No. 1.

[0040] 2 Test results and analysis 2.1 Effect of soil remediation agents on soil pH As can be seen from Table 3, compared with the control (CK), the pH value of the soil treated with the soil remediation bacteria agent (powder) (C1) and the soil remediation bacteria agent (granules) (C3) of the present invention increased year by year, which was significantly different from the other treatments. Among them, compared with the treatment with comparative example 1 (C2), the pH value of the soil treated with the soil remediation bacteria agent (powder) (C1) in Example 1 increased by 0.11, 0.24 and 0.38 units respectively in the three rice planting seasons of early rice in 2022, 2023 and 2024, and compared with conventional fertilization (C5), the pH value of the soil increased by 0.14, 0.26 and 0.41 units respectively; compared with the treatment with comparative example 1 (C4), the pH value of the soil treated with the soil remediation bacteria agent (granules) (C3) in the three rice planting seasons increased by 0.11, 0.23 and 0.36 units respectively, and compared with conventional fertilization (C5), it increased by 0.12, 0.24 and 0.39 units respectively.

[0041] Table 3 Effects of soil remediation agents on soil pH

[0042] Note: Different lowercase letters indicate significant differences among farmlands under different utilization treatments (P<0.05), the same below.

[0043] 2.2 Effects of soil remediation agents on the main physical and chemical properties of soil As can be seen from Table 4, compared with before the test, the soil bulk density showed a downward trend year by year after the use of soil remediation bacteria agent for three consecutive rice planting seasons for three years, which was significantly different from other treatments. At the end of the early rice test in 2024, the soil bulk density treated with the soil remediation bacteria agent (powder) (C1) of Example 1 was 1.21, which was 8.33% lower than that of the comparative example 1 (C2) and the porosity increased by 7.97%, while it was 10.37% lower than that of the conventional fertilization (C5) treatment and the porosity increased by 9.13%. The soil bulk density treated with the soil remediation bacteria agent (granules) (C3) of Example 1 was 1.22, which was 8.27% lower than that of the comparative example 1 (C4) treatment and the porosity increased by 7.62%; it was 9.63% lower than that of the conventional fertilization (C5) treatment and the porosity increased by 8.38%. It can be seen that no matter what form of soil remediation bacteria agent is applied, the physical properties of the soil can be improved.

[0044] All chemical indicators of the soil showed a trend of optimization year by year, and the soil fertility was further improved. Compared with the soil remediation bacteria agent + conventional fertilization treatment in Comparative Example 1, the pH, organic matter, alkaline nitrogen, available phosphorus, and available potassium of the soil treated with the soil remediation bacteria agent (powder) and soil remediation bacteria agent (granules) in Example 1 increased. After the early rice trial was completed in 2024, the pH of the soil treated with the soil remediation bacteria agent (powder) in Example 1 increased by 0.38 units compared with Comparative Example 1 (powder) + conventional fertilization; organic matter, alkaline nitrogen, available phosphorus, and available potassium increased significantly by 7.59%, 7.82%, 2.46%, and 2.37%, respectively; the pH of the soil increased by 0.41 units compared with conventional fertilization; organic matter, alkaline nitrogen, available phosphorus, and available potassium increased significantly by 8.06%, 9.23%, 11.86%, respectively. %, 2.84%; the pH of the soil treated with the soil remediation bacterial agent (granules) of Example 1 was increased by 0.36 units compared with that of the soil treated with Comparative Example 1 (granules) + conventional fertilization; the organic matter, alkaline-hydrolyzable nitrogen, available phosphorus, and available potassium were significantly increased by 5.38%, 7.11%, 2.17%, and 2.39%, respectively; the pH of the soil was increased by 0.39 units compared with that of the soil treated with conventional fertilization; the organic matter alkaline-hydrolyzable nitrogen, available phosphorus, and available potassium were significantly increased by 5.69%, 8.13%, 10.41%, and 2.57%, respectively.

[0045] Table 4 Effects of soil remediation agents on soil physical and chemical properties

[0046] The above results show that the application of the soil remediation bacterial agent of the present invention can reduce soil acidification and significantly improve the physical and chemical properties of the soil, and compared with the conventional Bacillus megaterium ( Bacillus megaterium ) The soil remediation bacterial agent obtained by fermentation culture has better improvement effect.

[0047] 2.3 Effects of soil remediation agents on rice growth period Field surveys and observations showed that rice seedlings in plots treated with both the soil remediation agent (powder) and the soil remediation agent (granules) showed better growth, with greener leaves and stronger plants. However, there were no significant differences in the main growth stages between the treatments (see Table 5).

[0048] Table 5 Effects of soil remediation agents on rice growth period

[0049] 2.4 Effects of soil remediation agents on rice yield As shown in Table 6, the yield of the soil remediation bacteria agent (powder) (C1) of Example 1 was significantly higher than that of the other treatments. Compared with the treatment of Comparative Example 1 (powder) + conventional fertilization (C2), the yield of the 2022 early rice, 2023 early rice and 2024 early rice treated with the soil remediation bacteria agent (powder) increased by 23.73 kg, 25.34 kg and 28.63 kg, respectively, and the yield increase rate reached 5.79%, 6.17% and 6.96%, respectively; compared with the conventional fertilization treatment, the yield of the 2022 early rice, 2023 early rice and 2024 early rice treated with the soil remediation bacteria agent (powder) increased by 32.8 kg, 32.77 kg and 35.47 kg, respectively, and the yield increase rate reached 8.19%, 8.12% and 8.77%, respectively.

[0050] Compared with the treatment of comparative example 1 (granules) + conventional fertilization (C4), the yield of early rice in 2022, 2023 and 2024 treated with the soil remediation bacteria agent (granules) (C3) of Example 1 increased by 24.16 kg, 26.26 kg and 29.82 kg, respectively, and the yield increase rate reached 5.92%, 6.42% and 7.30%, respectively; compared with the treatment of conventional fertilization (C5), the yield of early rice in 2022, 2023 and 2024 treated with the soil remediation bacteria agent (granules) of Example 1 increased by 31.8 kg, 31.59 kg and 33.84 kg, respectively, and the yield increase rate reached 7.94%, 7.83% and 8.37%, respectively. This shows that the application of the soil remediation bacteria agent (powder) and soil remediation bacteria agent (granules) of the present invention can significantly increase rice yield, and compared with conventional Bacillus megaterium ( Bacillus megaterium ) The soil remediation bacteria agent obtained by fermentation culture has a better yield-increasing effect.

[0051] Table 6 Effects of soil remediation agents on rice yield

[0052] 3.5 Effects of soil remediation agents on soil biological properties Soil microorganisms participate in the decomposition and transformation of soil substances and are a key determinant of soil fertility. Table 7 shows changes in the abundance of bacteria, fungi, and actinomycetes in the soil after the application of soil remediation agents. The abundance of the three major soil microbial groups ranked bacteria > actinomycetes > fungi, with significant differences compared to other treatments. After the 2024 early rice trial, the bacterial population in the C1 treatment increased by 15.46% compared to the C2 treatment and by 29.67% compared to conventional fertilization. The C3 treatment increased by 13.94% compared to the C4 treatment and by 27.92% compared to conventional fertilization.

[0053] Table 7 Effects of soil remediation agents on soil biological properties

[0054] 3 Experimental conclusions 3.1 Application of the soil remediation bacteria agent (powder) (C1) and the soil remediation bacteria agent (granules) (C3) of the present invention to rice can promote the growth of rice, have a certain promoting effect on increasing the thousand-grain weight and yield of rice, can significantly increase the pH value of the soil, improve the physical and chemical properties of the soil, and improve the biological properties of the soil.

[0055] 3.2 The soil remediation bacteria agent (powder) and conventional fertilization were used together (C1), which was beneficial to the increase of yield, and compared with the conventional Bacillus megaterium ( Bacillusmegaterium ) fermentation culture soil remediation bacteria agent (powder) + conventional fertilization (C2) compared with the treatment, the yield of early rice in 2022, early rice in 2023 and early rice in 2024 increased by 23.73kg, 25.34kg and 28.63kg respectively, and the yield increase rate reached 5.79%, 6.16% and 6.96% respectively; compared with the conventional fertilization treatment, the yield of early rice in 2022, early rice in 2023 and early rice in 2024 increased by 32.8kg, 32.77kg and 35.47kg respectively, and the yield increase rate reached 8.19%, 8.12% and 8.77% respectively; after the completion of the 2024 early rice trial, compared with the conventional Bacillus megaterium ( Bacillusmegaterium Compared with the conventional fertilization treatment (C2), the soil pH increased by 0.38 units, the bacterial count increased by 15.45%, and the organic matter, alkaline-hydrolyzable nitrogen, available phosphorus, and available potassium significantly increased by 7.59%, 7.82%, 2.46%, and 2.37%, respectively. The soil bulk density decreased by 8.33%, and the porosity increased by 7.97%. Compared with the conventional fertilization treatment, the soil pH increased by 0.41 units, the bacterial count increased by 29.67%, the organic matter, alkaline-hydrolyzable nitrogen, available phosphorus, and available potassium significantly increased by 8.06%, 9.23%, 11.86%, and 2.84%, respectively. The soil bulk density decreased by 10.37%, and the porosity increased by 9.12%. Rice yield increased significantly, the soil pH increased, and the physical and chemical properties improved.

[0056] 3.3 The combination of soil remediation bacteria agent (granules) and conventional fertilization (C3) is beneficial to increase production, compared with the conventional Bacillus megaterium ( Bacillusmegaterium ) fermentation culture soil remediation bacteria agent (granules) + conventional fertilization (C4) treatment, the yield of early rice in 2022, early rice in 2023 and early rice in 2024 increased by 24.16kg, 26.26kg and 29.82kg respectively, and the yield increase rate reached 5.92%, 6.42% and 7.30% respectively; compared with the conventional fertilization treatment, the yield of early rice in 2022, early rice in 2023 and early rice in 2024 increased by 31.8kg, 31.59kg and 33.84kg respectively, and the yield increase rate reached 7.94%, 7.83% and 8.37% respectively; after the completion of the 2024 early rice trial, compared with the conventional Bacillus megaterium ( Bacillusmegaterium Compared with the conventional fertilization treatment (C4), the soil pH increased by 0.36 units, the bacterial count increased by 13.94%, and the organic matter alkaline-hydrolyzable nitrogen, available phosphorus, and available potassium significantly increased by 5.38%, 7.11%, 2.17%, and 2.39%, respectively. The soil bulk density decreased by 8.27%, and the porosity increased by 7.62%. Compared with the conventional fertilization treatment, the soil pH increased by 0.39 units, and the bacterial count increased by 27.92%. The organic matter, alkaline-hydrolyzable nitrogen, available phosphorus, and available potassium significantly increased by 5.69%, 8.13%, 10.41%, and 2.57%, respectively. The soil bulk density decreased by 9.63%, and the porosity increased by 8.38%. The rice yield increased significantly, the soil pH increased, and the physical and chemical properties improved significantly.

[0057] It can be seen from the above results that the Bacillus megaterium ( Bacillus megaterium) The soil remediation agent prepared by Z101 fermentation culture has significant advantages over conventional Bacillus megaterium fermentation culture agents in increasing rice yield, improving soil pH, improving soil physical and chemical properties, and improving soil biological properties, providing a new application approach for Bacillus megaterium Z101.

[0058] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a soil remediation bacterial agent, characterized in that: The steps include: Bacillus megaterium ( Bacillus megaterium ) After activation, Z101 is inoculated into a fermentation liquid containing rice straw powder for fermentation and culture. After the fermentation is completed, the fermentation mixture is vacuum spray-dried to obtain a soil remediation bacteria powder; or the soil remediation bacteria powder is further mixed with auxiliary materials and water and granulated to obtain a soil remediation bacteria granule; the Bacillus megaterium Z101 strain was deposited in the Guangdong Provincial Microbial Culture Collection Center on December 9, 2019, with the deposit number GDMCC NO: 60928.

2. The method for preparing a soil remediation bacterial agent according to claim 1, wherein: The activation method comprises the following steps: inoculating the Bacillus megaterium Z101 strain into LB solid culture medium, and culturing the culture medium at 30-37° C. for 24-36 hours to obtain the activated strain.

3. The method for preparing a soil remediation bacterial agent according to claim 1, wherein: The fermentation liquid containing rice straw powder comprises the following components: Rice straw powder 50-100g / L, glucose 5-15g / L, soybean cake powder 5-15g / L, yeast powder 0.5-2g / L, sodium glutamate 0.5-2g / L, ammonium sulfate 0.5-1g / L, urea 0.2-1g / L, dipotassium hydrogen phosphate 0.2-0.5 g / L, magnesium sulfate 0.01-0.05g / L, manganese sulfate monohydrate 0.005-0.01g / L.

4. The method for preparing a soil remediation bacterial agent according to claim 1, wherein: The inoculum size of the fermentation culture is 2-5%.

5. The method for preparing a soil remediation bacterial agent according to claim 1, characterized in that: During the fermentation process, the pH is controlled at 7.0-7.5 by adding acid and alkali solutions; the temperature of the fermentation is controlled at 30-37° C., and the fermentation time is 36-72 hours.

6. The method for preparing a soil remediation bacterial agent according to claim 1, characterized in that: The auxiliary material is one or more of starch, dextrin and sucrose.

7. A soil remediation bacterial agent, characterized in that: Prepared by any one of the methods of claims 1 to 6; the soil remediation bacterial agent is a soil remediation bacterial powder or a soil remediation bacterial granule.

8. A soil remediation bacterial agent according to claim 7, characterized in that: The effective viable bacteria count of the soil remediation bacteria powder is ≥600 million / g, and the effective viable bacteria count of the soil remediation bacteria granules is ≥300 million / g.

9. Use of the soil remediation bacterial agent according to claim 7 or 8 in paddy field soil remediation and rice planting, characterized in that: The application method is: during the rice planting stage, the soil remediation bacteria agent is applied together with inorganic fertilizer to remediate the paddy field soil and promote rice growth.

10. The use of the soil remediation bacterial agent according to claim 9 in paddy field soil remediation and rice planting, characterized in that: The inorganic fertilizer is a mixture of high-concentration compound fertilizer with a total nutrient content of ≥40%, urea and potassium chloride; the dosage of the soil remediation bacteria agent and the inorganic fertilizer is: 150~250kg / mu of soil remediation bacteria agent, 20~40kg / mu of high-concentration compound fertilizer, 5~15kg / mu of urea, and 3~8kg / mu of potassium chloride.

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