Rice straw rotting agent, its preparation method and application

Abstract

This invention belongs to the field of microbial fermentation and bio-agriculture technology, and discloses a rice straw composting agent, its preparation method, and its application. The rice straw composting agent is prepared using Bacillus megaterium (BME). Bacillus megaterium Z101 is obtained through activation and fermentation. The application method is as follows: harvested rice straw is spread evenly in the paddy field, maintaining the water level to submerge the straw. Then, a diluted rice straw composting agent is applied to the surface of the spread rice straw for composting and fermentation, resulting in composted rice straw. The rice straw composting agent of this invention is a fermentation culture of Bacillus megaterium Z101. Verification has shown that compared to conventional Bacillus megaterium fermentation cultures on the market, it has higher rice straw composting efficiency and speed, facilitating on-site composting and returning of rice straw to the field, and providing a new application avenue for Bacillus megaterium Z101.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microbial fermentation and bio-agricultural technology, and particularly relates to a rice straw composting agent, a preparation method and application thereof. BACKGROUND

[0002] Compared with incineration, straw returning to field is a more environmentally friendly and sustainable agricultural waste treatment method. However, in the natural state, rice straw returning to field is slow to decompose and takes a long time, which affects the subsequent operation, and may also cause problems such as accelerated acidification of paddy soil, continuous decline of soil quality, and increased risk of disease and pest occurrence. In addition, Guangdong is located in a subtropical region, and the planting intensity is high, so the straw yield is huge. Therefore, it is of great significance to develop a new type of organic material composting agent to accelerate the composting and decomposition of rice straw through artificial intervention, and to reduce the negative impact of straw returning to field on agricultural production.

[0003] Bacillus megaterium, as an important phosphorus-solubilizing bacterium, is widely used in agricultural production. Optimizing the culture of Bacillus megaterium to make it into a bacterial fertilizer can improve soil fertility and increase yield. There are also corresponding reports on the application of Bacillus megaterium in crop straw composting. For example, the Chinese patent with publication number CN 114907152 A records the application of Bacillus megaterium strain RL-126 in promoting crop straw composting, which can improve the straw degradation rate, promote straw composting and the release of nutrient components, and increase soil enzyme activity. However, the composting fermentation process requires pre-crushing of corn straw, and the use of a water solution containing a nitrogen source for spraying, which is not convenient to use. In addition, it has not been verified whether the Bacillus megaterium has a further improved straw composting effect compared to ordinary Bacillus megaterium, especially for rice straw with a large yield and without the need for pre-crushing. SUMMARY

[0004] In order to promote efficient composting and returning to field of rice straw, promote the resource utilization of agricultural waste, and promote the sustainable development of agriculture, the purpose of the present application is to provide a rice straw composting agent, a preparation method and application thereof.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] A preparation method of a rice straw composting agent, comprising the following steps:

[0007] activating Bacillus megaterium (Bacillus megaterium) Z101 and inoculating it into a fermentation broth for fermentation culture until the effective viable count is greater than or equal to 200 million cfu / mL to obtain a rice straw composting agent. Bacillus megaterium The Bacillus megaterium Z101 strain was deposited at the Guangdong Microbial Culture Collection Center on December 09, 2019, and the deposit number is GDMCC NO: 60928.

[0008] The bacillus megaterium (Bacillus megaterium) Z101 used in the present application has been disclosed in Chinese patent application CN111592997 A. Bacillus megaterium )Z101 has been disclosed in Chinese patent application CN111592997 A.

[0009] Preferably, the method for activating is: inoculating bacillus megaterium Z101 strain to LB solid culture medium, culturing at 30-37℃ for 24-36h, to obtain the activated strain.

[0010] Preferably, the fermentation broth includes the following ingredients in the following amounts:

[0011] Glucose 10-15g / L, soybean cake powder 10-15g / L, yeast powder 0.2-1g / L, sodium glutamate 0.5-1g / L, ammonium sulfate 0.1-0.5g / L, urea 0.05-0.5g / L, dipotassium hydrogen phosphate 0.02-0.5g / L, magnesium sulfate 0.01-0.05g / L, manganese sulfate 0.005-0.01g / L.

[0012] Preferably, the inoculation amount of the fermentation culture is 3-5%.

[0013] Preferably, the pH is controlled to be 7.0-7.5 by adding acid or alkali solution during the fermentation culture process.

[0014] Preferably, the temperature of the fermentation culture is controlled to be 30-37℃, and the time is 36-48h.

[0015] A rice straw composting agent is prepared by the above method.

[0016] The application of the above rice straw composting agent in rice straw composting fermentation includes the following steps:

[0017] The harvested rice straw is laid flat in the rice field, the water level of the rice field is submerged in the rice straw, then the rice straw composting agent is diluted with water and applied to the surface of the laid rice straw for composting fermentation treatment, to obtain the composted rice straw.

[0018] Preferably, the average thickness of the laid rice straw in the rice field is 5±1cm, and the water level of the rice field is 5cm±1. Under the above conditions of the thickness of the laid rice straw and the water level, the best composting effect can be achieved.

[0019] Preferably, the volume ratio of the rice straw composting agent diluted with water is 1:200~400; and the acreage use amount of the rice straw composting agent is 1~3L.

[0020] Preferably, the time of the composting fermentation treatment is more than 30 days.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] (1) The rice straw composting agent of the present invention can accelerate the composting of rice straw, which helps rice straw to be composted and returned to the field on the spot and improves soil organic matter.

[0023] (2) The rice straw composting agent of the present invention is Bacillus megaterium (Betaminaria japonica). Bacillus megaterium The fermentation broth of Z101 has been verified to have higher rice straw composting efficiency and speed compared to the fermentation broth of conventional Bacillus megaterium on the market, providing a new application for Bacillus megaterium Z101. Attached Figure Description

[0024] Figure 1 The figure shows the average straw tensile strength over 30 days in different test sites and treatment groups in Example 4. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. Example 1

[0026] A method for preparing a rice straw composting agent includes the following steps:

[0027] Bacillus megaterium ( Bacillus megaterium Z101 (deposited at Guangdong Provincial Microbial Culture Collection Center on December 11, 2019, accession number GDMCC NO: 60928) was inoculated onto LB solid medium and cultured at 32-35℃ for 30 h. Active mycelia were then inoculated at 4 wt% into the fermentation broth for fermentation. The fermentation broth composition included: glucose 12 g / L, soybean meal 12 g / L, yeast extract 0.6 g / L, monosodium glutamate 0.8 g / L, ammonium sulfate 0.3 g / L, urea 0.2 g / L, K₂HPO₄ 0.2 g / L, magnesium sulfate 0.02 g / L, and manganese sulfate monohydrate 0.006 g / L. During fermentation, the pH was controlled to 7.0-7.5 by adding acid and alkali solutions, and the fermentation temperature was controlled at 32-35℃ for 36 h. The effective viable count of the fermentation broth was 260 million CFU / mL, yielding a rice straw composting agent. Example 2

[0028] A method for preparing a rice straw composting agent includes the following steps:

[0029] Bacillus megaterium ( Bacillus megateriumZ101 was inoculated onto LB solid medium and cultured at 30-32℃ for 24 hours. Active mycelium was then inoculated at 5 wt% into the fermentation broth for further fermentation. The fermentation broth composition included: glucose 15 g / L, soybean meal 15 g / L, yeast powder 1 g / L, monosodium glutamate 1 g / L, ammonium sulfate 0.5 g / L, urea 0.5 g / L, K₂HPO₄ 0.2 g / L, magnesium sulfate 0.02 g / L, and manganese sulfate monohydrate 0.006 g / L. During fermentation, the pH was controlled to 7.0-7.5 by adding acid and alkali solutions, and the fermentation temperature was controlled at 30-32℃ for 48 hours. The effective viable bacteria count in the fermentation broth was found to be 430 million CFU / mL, yielding a rice straw composting agent. Example 3

[0030] A method for preparing a rice straw composting agent includes the following steps:

[0031] Bacillus megaterium ( Bacillus megaterium Z101 was inoculated onto LB solid medium and cultured at 35-37℃ for 36 hours. Active mycelium was then inoculated into the fermentation broth at 3 wt% for further fermentation. The fermentation broth composition included: glucose 10 g / L, soybean meal 10 g / L, yeast extract 0.2 g / L, monosodium glutamate 0.5 g / L, ammonium sulfate 0.1 g / L, urea 0.05 g / L, K₂HPO₄ 0.2 g / L, magnesium sulfate 0.02 g / L, and manganese sulfate monohydrate 0.006 g / L. During fermentation, the pH was controlled to 7.0-7.5 by adding acid and alkali solutions, and the fermentation temperature was controlled at 35-37℃ for 40 hours. The effective viable bacteria count in the fermentation broth was found to be 220 million CFU / mL, yielding a rice straw composting agent.

[0032] Comparative Example 1

[0033] A method for preparing a rice straw composting agent includes the following steps:

[0034] Commercially available conventional Bacillus megaterium ( Bacillus megaterium (Sangon Biotech) activated the rice straw according to the method in Example 1, and then inoculated it at 4 wt% into the same fermentation broth as in Example 1. Fermentation culture was carried out until the effective viable bacteria count was detected to be 260 million CFU / mL, thus obtaining the rice straw composting agent. Example 4

[0035] The application of the rice straw composting agent obtained in this invention (using the rice straw composting agent of Example 1 as the experimental group) in the composting and fermentation of rice straw includes the following steps:

[0036] (1) Overview of the test site

[0037] The test was carried out in the rice test field of Yangguang Village and Songyuan Village in Pingtan Town, Huian District. The soil of the two test sites is loam, the soil fertility is medium and uniform, and the previous crop is rice.

[0038] (2) Test materials

[0039] The test materials are all rice straw. The rice variety planted in the early stage in Yangguang Village of Pingtan Town is Nanjingxiangzhan, and the rice variety planted in the early stage in Songyuan Village of Liangjing Town is Taixiangzhan.

[0040] (3) Test design

[0041] The test has 3 treatment groups, among which the test group (treatment group 1) uses 2L of the rice straw composting agent of Example 1 per mu to dilute 500L of water and apply on the surface of the laid rice straw; the conventional control group (treatment group 2) uses 2L of the rice straw composting agent of Comparative Example 1 per mu to dilute 500L of water and apply on the surface of the laid rice straw; the blank control group (treatment group 3) does not use any composting agent, and 500L of water is applied on the surface of the laid rice straw. Each treatment group is repeated 3 times, arranged randomly in blocks, and the test plot area is 20m 3 After the rice is harvested, the harvested rice straw is laid flat in the test plot with an average thickness of 5cm, and a dike is built between the test plots to maintain a water level of about 5cm to submerge the rice straw, and the field is kept moist throughout the period. The total fermentation period of the rice straw is 30 days, and the color and tensile force change indexes of the straw are recorded every 10 days: the color change of the straw is judged by visual observation; the degree of straw decomposition is represented by tensile force, and the determination method is as follows: one end of the rice straw is fixed, the other end is connected to a spring scale, then it is pulled with force and the weight (g) at the time of breaking of the rice straw is recorded.

[0042] (4) Results and analysis

[0043] 1. Change of straw During the test period, the color and tensile force change of the rice straw after applying the rice straw composting agent were recorded by fixed point investigation, and the results are shown in Table 1.

[0044] Table 1

[0045]

[0046] As shown in Table 1, after applying the composting agent of this invention in Pingtan Town, the straw appearance color changed to yellow, light brown, dark brown, and grayish-black every 10 days, with straw tensile strength decreasing by 41.9%, 40.2%, and 56.7%, respectively. In the conventional control group, the straw appearance color changed to yellow, light brown, light brown, and dark brown, with straw tensile strength decreasing by 41.1%, 35.1%, and 42.8%, respectively. In the blank control group, the straw appearance color changed to yellow, dark yellow, yellowish-brown, and light brown, with straw tensile strength decreasing by 25.4%, 19.6%, and 24.0%, respectively. Thirty days after application, both the experimental group and the conventional control group reached the fully composted state, while the blank control group reached the semi-composted state.

[0047] After applying the composting agent of this invention in Liangjing Town, the straw appearance color changed to yellow, light brown, dark brown, and grayish-black every 10 days, with straw tensile strength decreasing by 47.4%, 42.6%, and 61.5%, respectively. In the conventional control group, the straw appearance color changed to yellow, light brown, dark brown, and grayish-black, with straw tensile strength decreasing by 40.4%, 36.0%, and 54.8%, respectively. In the blank control group, the straw appearance color changed to yellow, dark yellow, light brown, and light brown, with straw tensile strength decreasing by 23.3%, 24.2%, and 24.3%, respectively. Thirty days after application, both the experimental group and the conventional control group reached a fully composted state, while the blank control group reached a semi-composted state.

[0048] The results showed that the application of the rice straw composting agent of this invention at the two test sites was significantly better than that of conventional Bacillus megaterium (BME). Bacillus megaterium All fermentation and composting agents can accelerate the composting of rice straw. The color changes during the composting process are consistent and obvious, with the rice straw color changing from yellow, light brown, dark brown, to gray-black. The straw tensile strength shows a clear decreasing trend. After 30 days of applying the composting agent, the rice straw has reached the composting state.

[0049] 2. The average straw pulling force of the above treatment groups over 30 days is as follows: Figure 1 As shown. By Figure 1 As shown in Table 1, after 30 days of application of the composting agent to rice straw in Pingtan Town, the rice straw tensile strength of treatment group 1 was the lowest, followed by treatment group 2, and the straw tensile strength of treatment group 3 was the highest. The average tensile strength of rice straw in treatment group 1, which applied the composting agent of this invention, was 790g, which was 366g less than that of treatment group 2 (a reduction of 31.7%), and 1595g less than that of treatment group 3 (a reduction of 66.9%). The difference between treatment group 1 and treatment group 2 was statistically significant, and the difference between treatment group 1 and treatment group 3 was highly statistically significant.

[0050] After 30 days of application of the rice straw composting agent in Liangjing Town, the tensile force of the rice straw in treatment group 1 is the smallest, that in treatment group 2 is the second, and that in treatment group 3 is the largest. The average tensile force of the rice straw in treatment group 1 is 552 g, which is 260 g less than that in treatment group 2, with a decrease of 32.0%, and is 1564 g less than that in treatment group 3, with a decrease of 73.9%. The difference between treatment group 1 and treatment group 2 reaches a significant level, and the difference between treatment group 1 and treatment group 3 reaches an extremely significant level. The results show that, after 30 days of application of the rice straw composting agent in the present application in the two test sites, the tensile force of the rice straw is obviously reduced compared with that of the conventional Bacillus megaterium (Bacillus megaterium) Bacillus megaterium fermented composting agent, and the rice straw has a better composting effect.

[0051] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement modes, and all shall be included in the protection scope of the present application.

Claims

1. The application of rice straw decomposing agent in rice straw decomposition fermentation, characterized in that: It comprises the following steps: ​ The harvested rice straw is laid flat in the rice field, the water level of the rice field is kept to flood the rice straw, then the rice straw composting agent is diluted with water and applied on the surface of the laid rice straw for composting and fermentation treatment, and the composted rice straw is obtained. The preparation method of the rice straw composting agent comprises the following steps: Bacillus megaterium ( Bacillus megaterium After activation, Z101 was inoculated into the fermentation broth for fermentation culture until the effective viable count was ≥200 million CFU / mL, thus obtaining a rice straw composting agent; the Bacillus megaterium Z101 strain was deposited at the Guangdong Provincial Microbial Culture Collection Center on December 11, 2019, with the accession number GDMCC NO: 60928.

2. The application of the rice straw composting agent according to claim 1 in the composting and fermentation of rice straw, characterized in that: The method for activating the strain is as follows: the strain Z101 of Bacillus megaterium is inoculated into LB solid culture medium, and cultured at 30-37℃ for 24-36h to obtain the activated strain.

3. The rice straw decomposing agent according to claim 1, wherein the rice straw decomposing agent is used in the decomposition and fermentation of rice straw. The fermentation liquor comprises the following ingredients: Glucose 10-15g / L, soybean cake powder 10-15g / L, yeast powder 0.2-1g / L, sodium glutamate 0.5-1g / L, ammonium sulfate 0.1-0.5g / L, urea 0.05-0.5g / L, dipotassium hydrogen phosphate 0.02-0.5g / L, magnesium sulfate 0.01-0.05g / L, manganese sulfate monohydrate 0.005-0.01g / L.

4. The rice straw decomposing agent according to claim 1, wherein the rice straw decomposing agent is used in the decomposition and fermentation of rice straw. The inoculation amount of the fermentation culture is 3-5%.

5. The rice straw decomposing agent according to claim 1, wherein the rice straw decomposing agent is used in the decomposition and fermentation of rice straw. During the fermentation culture, the pH is controlled to be 7.0-7.5 by adding acid and alkali solution; the temperature of the fermentation culture is controlled to be 30-37℃, and the time is 36-48h.

6. The rice straw decomposing agent according to claim 1, wherein the rice straw decomposing agent is used in the decomposition and fermentation of rice straw. The average thickness of the laid rice straw in the rice field is 5±1cm, and the water level of the rice field is 5cm±1.

7. The rice straw decomposing agent according to claim 1, wherein the rice straw decomposing agent is used in the decomposition and fermentation of rice straw. The volume ratio of the rice straw composting agent to water for dilution is 1:200-400; the use amount of the rice straw composting agent per mu is 1-3L.

8. The rice straw decomposing agent according to claim 1, wherein the rice straw decomposing agent is used in the decomposition and fermentation of rice straw. The time for the composting and fermentation treatment is more than 30 days.

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