Rice straw decomposition agent 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 rice straw decomposition agent as well as a preparation method and application thereof. The rice straw decomposition agent is obtained by adopting bacillus megatherium (Bacillus megatherium) Z101 to be subjected to fermentation culture after activation of the bacillus megatherium Z101. The application method comprises the steps that harvested rice straw is flatly laid in a rice field, the water level of the rice field is kept to submerge the rice straw, then the rice straw decomposition agent is diluted with water and then sprayed to the surface of the laid rice straw for decomposition fermentation treatment, and decomposed rice straw is obtained. The rice straw decomposing inoculant is a fermentation culture solution of bacillus megatherium Z101, and compared with a fermentation culture solution obtained by conventional bacillus megatherium in the market, the rice straw decomposing inoculant has higher rice straw decomposing efficiency and speed, in-situ decomposing and field returning of rice straw are facilitated, and a new application way is provided for the bacillus megatherium Z101.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial fermentation and bio-agriculture, and particularly relates to a rice straw composting agent and a preparation method and application thereof. Background Art

[0002] Compared with incineration, returning rice straw to the fields is a more environmentally friendly and sustainable way to treat agricultural waste. However, under natural conditions, returning rice straw to the fields decomposes slowly and takes a long time, affecting subsequent cropping operations. It may also lead to problems such as increased acidification of paddy soil, a continuous decline in soil quality, and an increased risk of pests and diseases. In addition, because Guangdong is located in the subtropical region, the planting intensity is high and the straw production is huge. Therefore, it is of great significance to develop a new type of organic material composting agent that can accelerate the composting and decomposition of rice straw through artificial intervention, while reducing the negative impact of returning rice straw to the fields on agricultural production.

[0003] Bacillus megaterium is widely used in agricultural production as an important phosphate-solubilizing bacterium. Optimizing its culture to make it into a microbial fertilizer can improve soil fertility and increase production and income. There are also corresponding reports on the application of Bacillus megaterium to the decomposition of crop straw. For example, the Chinese patent with publication number CN 114907152 A records the application of Bacillus megaterium RL-126 strain in promoting the decomposition of crop straw, which can improve the straw degradation rate, promote the decomposition of straw and the release of nutrients, and increase soil enzyme activity. However, its decomposition and fermentation process requires the corn straw to be crushed in advance, and it needs to be sprayed with an aqueous solution containing a nitrogen source, which is not convenient to use. In addition, it has not been verified whether this Bacillus megaterium has a further improved straw decomposition effect compared to ordinary Bacillus megaterium, especially for rice straw with huge yield and no need for pre-crushing. Summary of the Invention

[0004] In order to promote the efficient composting and returning of rice straw to the fields, promote the resource utilization of agricultural waste, and promote the sustainable development of agriculture, the purpose of the present invention is to provide a rice straw composting 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 rice straw composting agent comprises the following steps: Bacillus megaterium ( Bacillus megaterium ) After activation, Z101 is inoculated into the fermentation liquid for fermentation and cultured until the effective viable bacterial count is ≥200 million cfu / mL to obtain a rice straw composting agent; 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.

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

[0007] 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.

[0008] Preferably, the fermentation broth comprises the following components: 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 0.02-0.5 g / L, magnesium sulfate 0.01-0.05g / L, manganese sulfate monohydrate 0.005-0.01g / L.

[0009] Preferably, the inoculum size of the fermentation culture is 3-5%.

[0010] Preferably, during the fermentation process, the pH is controlled to be 7.0-7.5 by adding acid or alkaline solution.

[0011] Preferably, the fermentation culture temperature is controlled at 30-37°C and the fermentation time is 36-48 hours.

[0012] A rice straw composting agent is prepared by the method.

[0013] The application of the rice straw composting agent in rice straw composting and fermentation comprises the following steps: The harvested rice straw is spread flat on the rice field, and the water level in the rice field is kept to submerge the rice straw. The rice straw composting agent is then diluted with water and sprinkled on the surface of the spread rice straw for composting and fermentation to obtain composted rice straw.

[0014] Preferably, the average thickness of the rice straw spread in the paddy field is 5±1 cm, and the water level in the paddy field is 5 cm±1. Under the above rice straw spreading thickness and water level conditions, the best composting effect can be achieved.

[0015] Preferably, the volume ratio of the rice straw composting agent to water is 1:200-400; the dosage of the rice straw composting agent per mu is 1-3L.

[0016] Preferably, the composting and fermentation treatment takes more than 30 days.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The rice straw composting agent of the present invention can accelerate the composting of rice straw, help the rice straw to be composted on site and returned to the field, and increase the organic matter in the soil.

[0018] (2) The rice straw composting agent of the present invention is Bacillus megaterium ( Bacillus megaterium ) The fermentation culture medium of Z101 has been proven to have higher rice straw composting efficiency and speed than the fermentation culture medium obtained from conventional Bacillus megaterium on the market, providing a new application approach for Bacillus megaterium Z101. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a graph showing the average straw pulling force results for 30 days in different test sites and different treatment groups in Example 4. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto. Example 1

[0021] A method for preparing a rice straw composting agent comprises the following steps: Bacillus megaterium ( Bacillus megaterium Z101 (deposited with the Guangdong Provincial Center for Microbial Culture Collection on December 11, 2019, with the accession number GDMCC NO: 60928) was inoculated into LB solid medium and cultured at 32-35°C for 30 hours. Active mycelia were then collected and inoculated into a fermentation broth at a rate of 4 wt% for fermentation. The fermentation broth consisted of 12 g / L glucose, 12 g / L soybean meal powder, 0.6 g / L yeast extract, 0.8 g / L sodium glutamate, 0.3 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 within the range of 7.0-7.5 by adding acid and alkaline solutions. The fermentation temperature was maintained at 32-35°C for 36 hours. The effective viable bacterial count in the fermentation broth was 260 million cfu / mL, resulting in a rice straw composting agent. Example 2

[0022] A method for preparing a rice straw composting agent comprises the following steps: Bacillus megaterium ( Bacillus megateriumZ101 was inoculated into LB solid medium and cultured at 30-32°C for 24 hours. Active mycelia were collected and inoculated into a fermentation broth at a rate of 5 wt% for fermentation. The fermentation broth consisted of 15 g / L glucose, 15 g / L soybean meal powder, 1 g / L yeast powder, 1 g / L sodium glutamate, 0.5 g / L ammonium sulfate, 0.5 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 within the range of 7.0-7.5 by adding acid and alkaline solutions. The fermentation temperature was maintained at 30-32°C for 48 hours. The fermentation broth was tested and found to have an effective viable bacterial count of 430 million cfu / mL, thus producing a rice straw composting agent. Example 3

[0023] A method for preparing a rice straw composting agent comprises the following steps: Bacillus megaterium ( Bacillus megaterium Z101 was inoculated into LB solid medium and cultured at 35-37°C for 36 hours. Active mycelia were collected and inoculated into a fermentation broth at a rate of 3 wt%. The fermentation broth consisted of 10 g / L glucose, 10 g / L soybean meal powder, 0.2 g / L yeast extract, 0.5 g / L sodium glutamate, 0.1 g / L ammonium sulfate, 0.05 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 within the range of 7.0-7.5 by adding acid and alkaline solutions. The fermentation temperature was maintained at 35-37°C for 40 hours. The fermentation broth was tested and found to have an effective viable bacterial count of 220 million cfu / mL. This resulted in a rice straw composting agent.

[0024] Comparative Example 1 A method for preparing a rice straw composting agent comprises the following steps: Commercially available Bacillus megaterium ( Bacillus megaterium ) (Shenggong Biology) was activated according to the method of Example 1, and then inoculated into the same fermentation liquid as Example 1 at 4 wt % and fermented and cultured until the effective viable bacteria count was 260 million cfu / mL to obtain a rice straw composting agent. Example 4

[0025] The application of the rice straw composting agent obtained by the present invention (the rice straw composting agent of Example 1 is used as the experimental group) in rice straw composting and fermentation comprises the following steps: (1) Overview of the test site The experiment was conducted in rice experimental fields in Yangguang Village, Pingtan Town, Huiyang District, and Songyuan Village, Liangjing Town, Huiyang District. Both experimental sites had loam soil with medium and uniform fertility, and the previous crop was rice.

[0026] (2) Test materials The test materials were all rice straw. The rice variety planted in Yangguang Village, Pingtan Town in the early stage was Nanjing Xiangzhan, and the rice variety planted in Songyuan Village, Liangjing Town in the early stage was Tai Xiangzhan.

[0027] (3) Experimental design The experiment set up three treatment groups. The experimental group (treatment group 1) used 2L of rice straw composting agent of Example 1 mixed with 500L of water to irrigate the surface of the rice straw. The conventional control group (treatment group 2) used 2L of rice straw composting agent of Comparative Example 1 mixed with 500L of water to irrigate the surface of the rice straw. The blank control group (treatment group 3) did not apply any composting agent, but irrigated the surface of the rice straw with 500L of clean water. Each treatment group was repeated three times, arranged in random blocks, and the experimental area was 20m2. 3 After the rice was harvested, the rice straw was spread out in the experimental plots to an average thickness of 5 cm. Ridges were built between the experimental plots, and the water level in the paddy fields was maintained at approximately 5 cm, ideally enough to submerge the rice straw. The fields were kept moist throughout the fermentation period. The total fermentation period for the rice straw was 30 days, and changes in straw color and tensile strength were recorded every 10 days. Straw color changes were determined visually, while straw maturity was measured by tensile strength. The method was to fix one end of the rice straw and connect the other end to a spring scale. The rice straw was then pulled and its weight (g) was recorded when it broke.

[0028] (4) Results and analysis 1. Changes in rice straw During the experiment, fixed-point surveys were conducted to record the changes in color and tensile strength of rice straw after the application of rice straw composting agent. The results are shown in Table 1.

[0029] Table 1

[0030] As can be seen from Table 1, every 10 days after the application of the composting agent of the present invention in Pingtan Town, the appearance color of the straw changed to yellow, light brown, dark brown, and gray-black, and the straw pulling force decreased by 41.9%, 40.2%, and 56.7%, respectively; the appearance color of the straw in the conventional control group changed to yellow, light brown, light brown, and dark brown, and the straw pulling force decreased by 41.1%, 35.1%, and 42.8%, respectively; the appearance color of the straw in the blank control group changed to yellow, dark yellow, yellow-brown, and light brown, and the straw pulling force decreased by 25.4%, 19.6%, and 24.0%, respectively. 30 days after application, both the experimental group and the conventional control group reached a mature state, and the blank control group reached a semi-mature state.

[0031] After applying the composting agent of the present invention in Liangjing Town, every 10 days, the appearance color of the straw changed to yellow, light brown, dark brown, and gray-black, and the straw pulling force decreased by 47.4%, 42.6%, and 61.5%, respectively; the appearance color of the straw in the conventional control group changed to yellow, light brown, dark brown, and gray-black, and the straw pulling force decreased by 40.4%, 36.0%, and 54.8%, respectively; the appearance color of the straw in the blank control group changed to yellow, dark yellow, light brown, and light brown, and the straw pulling force decreased by 23.3%, 24.2%, and 24.3%, respectively. 30 days after application, both the experimental group and the conventional control group reached a mature state, and the blank control group reached a semi-mature state.

[0032] The results showed that the application of the rice straw composting agent of the present invention at the two test points was more effective than that of the conventional Bacillus megaterium ( Bacillus megaterium ) Fermentation composting agents can accelerate the composting of rice straw. The color changes during the composting process are consistent and obvious. The color changes of rice straw are yellow, light brown, dark brown, and gray-black. The straw pulling force has a significant trend of decreasing. The rice straw has reached a mature state 30 days after the application of the composting agent.

[0033] 2. The average straw pulling force of the above treatment groups after 30 days is as follows: Figure 1 As shown. Figure 1 As shown in Table 1, 30 days after the rice straw in Pingtan Town was treated with the composting agent, the rice straw pulling force in treatment group 1 was the lowest, followed by treatment group 2, and the highest in treatment group 3. The average rice straw pulling force in treatment group 1, which was treated with the rice straw composting agent of the present invention, was 790 g, a decrease of 366 g (31.7%) compared to treatment group 2, and a decrease of 1595 g (66.9%) compared to treatment group 3. The difference between treatment groups 1 and 2 was significant, and the difference between treatment groups 1 and 3 was extremely significant.

[0034] After 30 days of application of the composting agent to the rice straw in Liangjing Town, the same performance was shown: the rice straw pulling force of treatment group 1 was the smallest, followed by treatment group 2, and the straw pulling force of treatment group 3 was the largest. The average rice straw pulling force of treatment group 1 that applied the rice straw composting agent of the present invention was 552g, which was 260g less than that of treatment group 2, with a reduction of 32.0%, and 1564g less than that of treatment group 3, with a reduction of 73.9%. The difference between treatment group 1 and treatment group 2 reached a significant level, and the difference between treatment group 1 and treatment group 3 reached an extremely significant level. The results showed that after 30 days of application of the rice straw composting agent of the present invention in the two test sites, the rice straw pulling force was significantly greater than that of the conventional Bacillus megaterium ( Bacillus megaterium ) The amount of fermentation composting agents was significantly reduced, and rice straw had a better composting effect.

[0035] 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 rice straw composting agent, characterized in that: The steps include: Bacillus megaterium ( Bacillus megaterium ) After activation, Z101 is inoculated into the fermentation liquid for fermentation and cultured until the effective viable bacterial count is ≥200 million cfu / mL to obtain a rice straw composting agent; the Bacillus megaterium Z101 strain was deposited in the Guangdong Provincial Microbial Culture Collection Center on December 11, 2019, with the deposit number GDMCC NO: 60928.

2. The method for preparing a rice straw composting 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 rice straw composting agent according to claim 1, wherein: The fermentation broth comprises the following components: 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 0.02-0.5 g / L, magnesium sulfate 0.01-0.05g / L, manganese sulfate monohydrate 0.005-0.01g / L.

4. The method for preparing a rice straw composting agent according to claim 1, wherein: The inoculum size of the fermentation culture is 3-5%.

5. The method for preparing a rice straw composting agent according to claim 1, wherein: 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 36-48 hours.

6. A rice straw composting agent, characterized in that: Prepared by any one of the methods of claims 1 to 5.

7. Use of the rice straw composting agent according to claim 6 in rice straw composting and fermentation, characterized in that: The steps include: The harvested rice straw is spread flat on the rice field, and the water level in the rice field is kept to submerge the rice straw. The rice straw composting agent is then diluted with water and sprinkled on the surface of the spread rice straw for composting and fermentation to obtain composted rice straw.

8. The use of a rice straw composting agent according to claim 7 in rice straw composting and fermentation, characterized in that: The average thickness of the rice straw spread in the paddy field is 5±1 cm, and the water level in the paddy field is 5 cm±1.

9. The use of a rice straw composting agent according to claim 7 in rice straw composting and fermentation, characterized in that: The volume ratio of the rice straw composting agent diluted with water is 1:200-400; the per mu usage of the rice straw composting agent is 1-3L.

10. Use of a rice straw composting agent according to claim 7 in rice straw composting and fermentation, characterized in that: The time for the composting and fermentation treatment is more than 30 days.

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