Low-carbon straw multifunctional biological compound fertilizer as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of crop straw treatment, and particularly discloses a low-carbon straw multifunctional biological compound fertilizer as well as a preparation method and application thereof. According to the biological compound fertilizer provided by the invention, functional microbial strains are scientifically proportioned, a microbial immobilization technology is utilized for loading, and efficient strains, EM bacteria and a nitrification inhibitor are combined for application, so that the straw returning effect can be improved, carbon sequestration and emission reduction can be realized, and agricultural sustainable development can be promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of crop straw processing, and in particular relates to a low-carbon straw multifunctional bio-compound fertilizer and a preparation method and application thereof. Background Art

[0002] In current agricultural practice, returning straw to the field in situ as an important measure for resource recycling and soil fertility improvement is widely adopted, but it still faces multiple challenges. First, the natural degradation process of straw is slow, which is mainly attributed to its high content of cellulose and hemicellulose, which are difficult to be directly used by soil microorganisms, resulting in delayed nutrient release and affecting the timely absorption of nutrients by crops. Second, the pathogens and pest eggs carried in the straw become potential sources of pests and diseases for subsequent crops after returning to the field, increasing the difficulty and cost of pest and disease prevention. Third, the regulation of nitrogen conversion and greenhouse gas emissions during the process of returning straw to the field is insufficient, resulting in serious nitrogen losses, while increasing greenhouse gas emissions and causing adverse effects on the environment. Fourth, in actual transportation, microbial fertilizers still have problems with unstable fertilizer efficacy and short fertilizer shelf life. Summary of the invention

[0003] In view of the many problems existing in the above-mentioned background technology, the present invention aims to provide a straw composting agent and its preparation method and application. The present invention prepares a straw composting agent by combining the raw powder of composite functional microbial agent with EM bacteria and nitrification inhibitor. The straw composting agent of the present invention can achieve rapid composting of straw, effective transformation of nutrients, significant improvement of soil microecological environment, stable fertilizer efficiency and sequestration of soil carbon. This innovative technology not only reduces agricultural production costs, but also promotes the improvement of farmland fertility and the realization of carbon fixation and emission reduction goals, providing strong support for the sustainable development of agriculture.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] One of the technical solutions is a straw composting agent, which includes the following components by weight: 10-20 parts of corn straw, 50-60 parts of raw powder of composite functional microbial agent, 10-20 parts of nitrification inhibitor, and 10-20 parts of EM bacteria.

[0006] The composite functional microbial agent raw powder is composed of the following single functional microbial agent raw powders by weight: 20-30 parts of functional microbial agent raw powder 1 (Staphylococcus pseudoxylosus raw powder), 20-30 parts of functional microbial agent raw powder 2 (Phanerochaete chrysosporium raw powder) and 1-5 parts of functional microbial agent raw powder 3 (nitrite oxidizing bacteria raw powder).

[0007] The nitrification inhibitor is selected from any one of nitrogen pyridine, dicyandiamide, and 3,4-dimethylpyrazole phosphate (DMPP).

[0008] The EM bacteria are rich in various beneficial microorganisms, such as photosynthetic bacteria, lactic acid bacteria, yeast, fermentative filamentous bacteria, actinomycetes, etc., which can improve the soil microecological environment, promote plant growth, and reduce the occurrence of diseases.

[0009] The length of the corn stalks is 3-5 cm.

[0010] The method for preparing the functional microbial agent raw powder comprises the following steps:

[0011] S1. Inoculate the functional microbial agent into the composite culture medium, activate and culture for 24 to 48 hours, the activation temperature of Staphylococcus pseudoxylosus is 25-30°C, the activation temperature of Phanerochaete chrysosporium is 28-32°C, and the activation temperature of nitrite oxidizing bacteria is 30-35°C, so that the strains reach the logarithmic growth phase, and preserve the bacterial solution;

[0012] S2. The bacterial solution obtained in step S1 is mixed with biochar, and after vibration adsorption, the mixture is passed through a 200-mesh sieve, washed, dried, and crushed to obtain a raw powder of a functional microbial agent.

[0013] Furthermore, in step S2, the biochar is nitrogen-phosphorus loaded biochar; preferably, the preparation method of the biochar is: firstly calcining corn stalks at high temperature to obtain biochar, then adding the biochar to a mixed solution containing urea and diammonium hydrogen phosphate, ultrasonically treating for 2 hours, drying, and pyrolyzing the solid powder at 600°C for 30 minutes to obtain nitrogen-phosphorus loaded biochar; wherein the mass ratio of urea, diammonium hydrogen phosphate and biochar is 2-3:4-5:10.

[0014] Furthermore, the conditions for obtaining biochar by high-temperature calcination of corn straw are: pyrolysis at 600°C for 1 hour.

[0015] Furthermore, the oscillation adsorption conditions are: constant temperature oscillation adsorption at 25-35°C and 160-220r / min for 24h-48h.

[0016] Furthermore, the bacterial liquid and the biochar were mixed in a ratio of 10-15 mL: 1 g.

[0017] Further, in step S1, the components of the composite culture medium per liter are: 250-300g glucose, 150-200g soybean meal powder, 100-120g magnesium sulfate, 10-20g corn stalk powder, 30-50g potassium dihydrogen phosphate, 8-10g vitamin B1 and the balance of water, and the composite culture medium has a pH of 7.0. The particle size of the corn stalk powder is sieved through a 60-100 mesh sieve.

[0018] The second technical solution is a method for preparing the above-mentioned straw composting agent. According to weight, take 10-20 parts of corn straw, 50-60 parts of composite functional microbial agent raw powder, 10-20 parts of nitrification inhibitor, and 10-20 parts of EM bacteria, mix and stir evenly to obtain the straw composting agent.

[0019] Technical solution three, the application of the above-mentioned straw composting agent and the straw composting agent prepared by the above-mentioned method in returning straw to the field in situ, fixing carbon, and improving soil nutrients. The straw composting agent is suitable for gramineous crop straw. The soil nutrients refer to one or more of organic matter, available phosphorus, and available potassium.

[0020] The composite functional microbial agent raw powder, one of the main components of the straw composting agent provided by the present invention, is obtained by inoculating the functional microbial agent into a composite culture medium for activation culture. The corn straw powder added to the composite culture medium is used as an inducer to induce the cellulose degradation ability of the microbial agent, which can greatly enhance the cellulose degradation ability of the microorganisms after culture. This method improves the ability of the straw composting agent to degrade cellulose and also greatly reduces the cost of preparing the straw composting agent. Glucose, as a carbon source, provides the main nutrient for the growth of the microbial agent, soybean meal powder, as a nitrogen source, provides the required nitrogen elements for the microbial agent to synthesize proteins and other cellular substances, magnesium sulfate, as an inorganic salt, provides the microbial agent with magnesium ions required for enzyme activators, potassium dihydrogen phosphate provides the microbial agent with phosphorus and potassium sources, and vitamin B1 can promote microbial metabolism.

[0021] After the functional microbial agent is activated and cultured, it is loaded on nitrogen and phosphorus loaded biochar using microbial immobilization technology to obtain the functional microbial agent powder. This method can play a role in carbon sequestration, improve soil environmental quality (reduce organic carbon mineralization in the soil), reduce soil greenhouse gas emissions, reduce fertilizer use, and promote crop yields. It is a new way to fix carbon and reduce emissions.

[0022] The straw composting agent provided by the present invention can not only effectively promote the decomposition of straw and the conversion of nutrients, but also improve the soil microecological environment through the action of the composite functional microbial agent powder and EM bacteria, reduce the incidence of plant diseases, and promote the healthy growth of crops. At the same time, the addition of nitrification inhibitors also helps to reduce nitrogen loss and greenhouse gas emissions, achieving the goals of improving farmland fertility and fixing carbon emissions.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] The present invention provides a straw composting agent, which can improve the effect of returning straw to the field, fix carbon and reduce emissions, and promote the sustainable development of agriculture by scientifically proportioning functional microbial strains and utilizing microbial immobilization technology to load and jointly apply high-efficiency strains with EM bacteria and nitrification inhibitors.

[0025] The straw decomposition and nutrient conversion are promoted through scientific proportioning: the straw composting agent of the present invention is rich in microorganisms, Staphylococcus pseudoxylosus and Phanerochaete chrysosporium can quickly decompose the cellulose, hemicellulose and other difficult-to-degrade components in the straw, accelerate the composting process of the straw, and quickly convert the nutrients in the straw into forms that can be absorbed and utilized by plants, such as ammonium nitrogen, nitrate nitrogen, phosphorus, potassium, etc., thereby improving soil fertility; nitrite oxidizing bacteria can effectively inhibit nitrification in the soil and reduce the loss of nitrogen fertilizer in the process of conversion to nitrate nitrogen. The three bacteria together achieve the improvement of farmland fertility.

[0026] Improve soil microecological environment: The addition of EM bacteria to the straw composting agent of the present invention further enriches the microbial community in the soil and forms a good microecological system. These microorganisms effectively inhibit the reproduction of pathogens and pests through competition, symbiosis and other relationships, reduce the incidence of plant diseases, and create a healthy soil environment for crop growth.

[0027] Reduce greenhouse gas emissions and nitrogen losses: The nitrification inhibitor and nitrite oxidizing bacteria in the straw composting agent of the present invention can effectively inhibit nitrification in the soil, reduce the loss of nitrogen fertilizer in the process of conversion to nitrate nitrogen, and reduce the emission of greenhouse gases such as CH4. This not only improves the utilization rate of nitrogen fertilizer, but also reduces environmental pollution, achieving the goal of improving farmland fertility and fixing carbon emissions.

[0028] Stable long-term fertilizer effect: By fixing the functional microbial strains on biochar, the pore structure and adsorption properties of biochar can be used to provide a good growth environment for microorganisms and protect them from adverse external factors. In addition, biochar itself has a certain nutrient release capacity and soil improvement effect, forming a synergistic effect with microbial fertilizers.

[0029] In summary, the straw composting agent of the present invention effectively solves the problems existing in the traditional straw returning technology through its unique formula and efficacy, and provides strong support for the sustainable development of agriculture. The invention not only has significant economic and environmental benefits, but also has important promotion and application value. DETAILED DESCRIPTION

[0030] The applicant will further explain the technical solution of the present invention in detail below in conjunction with specific embodiments. It should be understood that the following content should not be interpreted as limiting the protection scope of the present invention in any way.

[0031] The following preparation examples 1 to 3 respectively provide a microbial agent culture medium for a straw composting agent; the raw materials used are all commercially available products, glucose: purchased from Suzhou Quanding Chemical Technology Co., Ltd.; soybean meal powder: purchased from Shandong Hongwei Biotechnology Co., Ltd.; magnesium sulfate: purchased from Weifang Botai Chemical Co., Ltd.; potassium dihydrogen phosphate: purchased from Qingdao Hisense Biochemistry Co., Ltd.; sodium tetraborate (pH buffer) was purchased from Hubei Rishengchang New Material Technology Co., Ltd.; corn straw powder was obtained by crushing dry corn straw and passing it through a 100-mesh sieve.

[0032] Preparation Example 1

[0033] The preparation steps of the liquid culture medium of microbial inoculant for straw composting agent provided in this preparation example are as follows: take 300g of glucose, 200g of soybean meal powder, 120g of magnesium sulfate, 20g of corn straw powder, 50g of potassium dihydrogen phosphate and 10g of vitamin B1, add appropriate amount of water to mix, then add water to 1L, and use sodium tetraborate (pH buffer) to adjust pH=7.0.

[0034] Preparation Example 2

[0035] The preparation steps of the liquid culture medium of microbial inoculant for straw composting agent provided in this preparation example are as follows: take 250g of glucose, 150g of soybean meal powder, 100g of magnesium sulfate, 10g of corn straw powder, 30g of potassium dihydrogen phosphate and 8g of vitamin B1, add appropriate amount of water to mix, then add water to 1L, and use sodium tetraborate (pH buffer) to adjust pH=7.0.

[0036] Preparation Example 3

[0037] The preparation steps of the liquid culture medium of microbial inoculant for straw composting agent provided in this preparation example are as follows: take 280g of glucose, 180g of soybean meal powder, 110g of magnesium sulfate, 15g of corn straw powder, 40g of potassium dihydrogen phosphate and 9g of vitamin B1, add appropriate amount of water to mix, then add water to 1L, and use sodium tetraborate (pH buffer) to adjust pH=7.0.

[0038] The following culture examples 1 to 3 respectively provide a method for preparing a functional microbial agent powder; the functional microbial agents used are as follows: Staphvlococcus pseudooxylosus, named XW-4, registered in GenBank, numbered OO443074.1; Phanerochaetechrysosporium CGMCC 5.0776, purchased from the Culture Collection of the Chinese Academy of Sciences; nitrite oxidizing bacteria: Nitrobacter Winogradskyi Y3-2, CCTCC NO: M2014203, purchased from the China Center for Type Culture Collection.

[0039] Culture Example 1

[0040] The method for preparing the functional microbial agent powder provided in this culture example comprises the following steps:

[0041] S1. Pre-culture

[0042] Staphylococcus pseudoxylosus (XW-4), Phanerochaete chrysosporium (CGMCC 5.0776) and nitrite oxidizing bacteria were inoculated into the composite culture medium prepared in Preparation Example 1, respectively. The activation temperature of Staphylococcus pseudoxylosus was controlled to be 25-30° C., the activation temperature of Phanerochaete chrysosporium was controlled to be 28-32° C., and the activation temperature of nitrite oxidizing bacteria (bacteria) was controlled to be 30-35° C. The activation culture was carried out for 24 to 48 hours to allow the strains to reach the logarithmic growth phase, and the bacterial solution was preserved.

[0043] S2, carbon-based functional microbial fixative

[0044] The Staphylococcus pseudoxylosus bacterial solution, the Phanerochaete chrysosporium bacterial solution, and the nitrite oxidizing bacteria bacterial solution activated in step S1 were mixed with nitrogen and phosphorus loaded biochar in a ratio of 10 mL: 1 g, and then adsorbed and fixed at a constant temperature of 35°C and 160 r / min for 24 hours to obtain a carbon-based functional microbial fixed solution.

[0045] The preparation method of the nitrogen-phosphorus loaded biochar is as follows: firstly, corn stalks are placed in a muffle furnace for pyrolysis at 600°C for 1 hour, cooled to room temperature and taken out to obtain biochar; 2.17g urea and 4.35g diammonium hydrogen phosphate are weighed and dissolved in water, and the volume is fixed to 1L with deionized water, and then 10g biochar is added, and after ultrasonic treatment for 2 hours, the solid powder is dried, placed in a muffle furnace for pyrolysis at 600°C for 30 minutes, cooled to room temperature and taken out to obtain nitrogen-phosphorus loaded biochar. The obtained nitrogen-phosphorus loaded biochar material is tested by ICP, and the C, N, P element ratio is 0.5%:0.5%:1.

[0046] S3, functional microbial agent powder

[0047] The carbon-based functional microbial fixed solution obtained in step S2 was filtered through a 200-mesh sieve, then slowly rinsed with 0.85% sterile saline, dried at room temperature for 24 hours, and then crushed into fine powder to obtain functional microbial agent raw powders: Staphylococcus pseudoxylosus raw powder, Phanerochaete chrysosporium raw powder, and nitrite oxidizing bacteria raw powder.

[0048] Culture Example 2

[0049] Staphylococcus pseudoxylosus (XW-4), Phanerochaete chrysosporium (CGMCC 5.0776) and nitrite oxidizing bacteria were inoculated into the composite culture medium prepared in Preparation Example 2, respectively. The other operation steps were exactly the same as those in Culture Example 1.

[0050] Culture Example 3

[0051] Staphylococcus pseudoxylosus (XW-4), Phanerochaete chrysosporium (CGMCC 5.0776) and nitrite oxidizing bacteria were inoculated into the composite culture medium prepared in Preparation Example 3, respectively. The other operation steps were exactly the same as those in Culture Example 1.

[0052] Experimental testing

[0053] The effective live bacteria count and cellulase activity in the original powder of the functional microbial agent cultured in culture examples 1 to 3 were tested, and the test results were recorded in Table 1;

[0054] Table 1

[0055]

[0056] As shown in Table 1, the raw powder of Staphylococcus pseudoxylosus and Phanerochaete chrysosporium obtained in Culture Example 1 have the strongest ability to degrade fiber. The raw powder of Staphylococcus pseudoxylosus, Phanerochaete chrysosporium and nitrite oxidizing bacteria obtained in Culture Example 1 and other functional microbial agent raw powders were used in the subsequent preparation of straw composting agents.

[0057] The following examples 1 to 3 respectively provide a method for preparing a straw composting agent; the raw powder of Staphylococcus pseudoxylosus, the raw powder of Phanerochaete chrysosporium and the raw powder of nitrite oxidizing bacteria used are prepared by culture example 1. The corn straw used is dry corn straw, which is crushed into small segments of 5 cm. The nitrification inhibitor used is 3,4-dimethylpyrazole phosphate, which is purchased from Wuhan Jiyesheng Chemical Co., Ltd. The EM bacteria (bacterial powder) used was purchased from Shandong Junde Biotechnology Co., Ltd.

[0058] Example 1

[0059] The preparation method of the straw composting agent provided in this embodiment includes the following steps: first, take 15 kg of raw powder of Staphylococcus pseudoxylosus, 15 kg of raw powder of Phanerochaete chrysosporium, and 1 kg of raw powder of nitrite oxidizing bacteria, stir and mix them evenly to obtain raw powder of composite functional microbial agent; then take 5.2 kg of corn straw, 31 kg of raw powder of composite functional microbial agent, 5.2 kg of nitrification inhibitor, and 5.2 kg of EM bacteria, stir and mix them evenly to obtain the straw composting agent.

[0060] Example 2

[0061] The preparation method of the straw composting agent provided in this embodiment includes the following steps: first, take 12.5 kg of raw powder of Staphylococcus pseudoxylosus, 12.5 kg of raw powder of Phanerochaete chrysosporium, and 1.25 kg of raw powder of nitrite oxidizing bacteria, stir and mix them evenly to obtain raw powder of composite functional microbial agent; then, take 4.38 kg of corn straw, 26.25 kg of raw powder of composite functional microbial agent, 4.38 kg of nitrification inhibitor, and 4.38 kg of EM bacteria, stir and mix them evenly to obtain the straw composting agent.

[0062] Example 3

[0063] The preparation method of the straw composting agent provided in this embodiment includes the following steps: first, take 10 kg of raw powder of Staphylococcus pseudoxylosus, 10 kg of raw powder of Phanerochaete chrysosporium, and 0.5 kg of raw powder of nitrite oxidizing bacteria, stir and mix them evenly to obtain raw powder of composite functional microbial agent; then, take 3.42 kg of corn straw, 20.5 kg of raw powder of composite functional microbial agent, 3.42 kg of nitrification inhibitor, and 3.42 kg of EM bacteria, stir and mix them evenly to obtain the straw composting agent.

[0064] Experimental testing

[0065] A test field (4m*5m) was selected, 10.0kg of wheat straw was crushed into 5cm small segments and evenly spread in the field, and the straw composting agent provided in Examples 1 to 3 was evenly spread in the field where the straw was laid according to the dosage of 2kg of straw composting agent per mu, and the straw and straw composting agent were turned to mix evenly, and the initial humidity of the fermented material was controlled between 55% and 65%, which was conducive to microbial growth and avoided anaerobic fermentation caused by excessive moisture. The performance of the straw composting agent provided in Examples 1 to 3 was tested, and a blank control test was performed on the field where the straw was laid without adding the straw composting agent; during the period, the pH value of the fermented material was monitored and adjusted to 6.5-7.5 (if necessary, an appropriate amount of lime or potassium dihydrogen phosphate and other regulators were added for adjustment); the pile was turned once every 3 days to promote oxygen to enter the pile body and accelerate microbial activity. After a period of fermentation, when the pile body temperature gradually decreases, the color becomes darker, there is no bad smell and a certain amount of humus is produced, the straw can be considered to be fully decomposed. Specifically, the test items are as follows:

[0066] 1. Detect the maximum temperature and duration of the straw after adding the straw composting agent, and record the above test results in Table 2;

[0067] 2. Detect the weight of the straw before and after 50 days of decomposition, calculate the weight loss rate of the straw after 50 days of decomposition, and record the above test results in Table 2;

[0068] 3. After 50 days of composting with the straw composting agent, the straw was returned to the field, and the growth of pests and weeds was observed to detect the pest and weed damage rate, and the above test results were recorded in Table 2.

[0069] Table 2 Summary of the test results of straw composting agent performance in Examples 1 to 3

[0070]

[0071]

[0072] It can be seen from the results in Table 2 that when the straw composting agent is not added, the maximum temperature of the straw can only reach 45°C and the duration is not long. After the straw composting agent provided in the present application is added, the maximum temperature can reach above 50°C and the duration is relatively long (more than 8 days), especially when the straw composting agent provided in Example 1 is added, the maximum temperature can reach 70°C and the duration is as long as 10 days; when the straw composting agent is not added, the straw weight loss rate due to its own degradation can only reach 20%. After the straw composting agent provided in the present application is added, the straw weight loss rate can reach more than 57%; when the straw composting agent is not added, the pest and disease rate of the straw after returning to the field is 10.5%. After the straw composting agent provided in the present application is added, the pest and disease rate of the straw after returning to the field is below 0.3%. This shows that the straw composting agent provided in the present application can achieve rapid temperature rise during the straw composting process, and the high temperature lasts for a long time; at the same time, the straw composting agent provided in the present application has a good effect on the composting and degradation of the straw, and there will be no pests and diseases when the composted and degraded straw is returned to the field.

[0073] Comparative Example 1

[0074] Based on Example 1, the difference between this comparative example and Example 1 is that: no nitrite oxidizing bacteria raw powder is added in this comparative example; specifically: 15 kg of Staphylococcus pseudoxylosus raw powder and 15 kg of Phanerochaete chrysosporium raw powder are taken and stirred and mixed evenly to obtain a composite functional microbial agent raw powder; then 5.2 kg of corn straw, 30 kg of composite functional microbial agent raw powder, 5.2 kg of nitrification inhibitor and 5.2 kg of EM bacteria are taken and stirred and mixed evenly to obtain a straw composting agent.

[0075] Comparative Example 2

[0076] Based on Example 1, the difference between this comparative example and Example 1 is that: this comparative example does not add the raw powder of Phanerochaete chrysosporium; specifically: 15 kg of raw powder of Staphylococcus aeruginosa and 1 kg of raw powder of nitrite oxidizing bacteria are taken and stirred and mixed evenly to obtain the raw powder of composite functional microbial agent; then 5.2 kg of corn straw, 16 kg of raw powder of composite functional microbial agent, 5.2 kg of nitrification inhibitor and 5.2 kg of EM bacteria are taken and stirred and mixed evenly to obtain the straw composting agent.

[0077] Comparative Example 3

[0078] Based on Example 1, the difference between this comparative example and Example 1 is that: no Staphylococcus aeruginosa powder is added in this comparative example; specifically: 15 kg of Pseudocercos chrysosporium powder and 1 kg of nitrite oxidizing bacteria powder are taken and stirred and mixed evenly to obtain a composite functional microbial agent powder; then 5.2 kg of corn straw, 16 kg of composite functional microbial agent powder, 5.2 kg of nitrification inhibitor and 5.2 kg of EM bacteria are taken and stirred and mixed evenly to obtain a straw composting agent.

[0079] Comparative Example 4

[0080] Based on Example 1, the difference between this comparative example and Example 1 is that: this comparative example does not add the raw powder of Staphylococcus pseudoxylosus and the raw powder of Phanerochaete chrysosporium; specifically: 5.2 kg of corn straw, 1 kg of nitrite oxidizing bacteria raw powder, 5.2 kg of nitrification inhibitor and 5.2 kg of EM bacteria are taken and stirred to mix evenly to prepare a straw composting agent.

[0081] Comparative Example 5

[0082] Based on Example 1, the difference between this comparative example and Example 1 is that: this comparative example does not add the raw powder of Staphylococcus pseudoxylosus and the raw powder of nitrite oxidizing bacteria; specifically: 5.2 kg of corn straw, 15 kg of raw powder of Phanerochaete chrysosporium, 5.2 kg of nitrification inhibitor and 5.2 kg of EM bacteria are taken and stirred to mix evenly to prepare a straw composting agent.

[0083] Comparative Example 6

[0084] Based on Example 1, the difference between this comparative example and Example 1 is that no nitrification inhibitor and EM bacteria are added in this comparative example; specifically, 15 kg of Staphylococcus aeruginosa powder, 15 kg of Phanerochaete chrysosporium powder, and 1 kg of nitrite oxidizing bacteria powder are first taken and stirred and mixed evenly to obtain a composite functional microbial agent powder; then 5.2 kg of corn straw and 31 kg of composite functional microbial agent powder are taken and stirred and mixed evenly to obtain a straw composting agent.

[0085] Comparative Example 7

[0086] Based on Example 1, the difference between this comparative example and Example 1 is that: this comparative example does not add the raw powder of the composite functional microbial agent; specifically: 5.2 kg of corn straw, 5.2 kg of nitrification inhibitor and 5.2 kg of EM bacteria are taken and stirred to mix evenly to prepare a straw composting agent.

[0087] Comparative Example 8

[0088] Based on Example 1, the difference between this comparative example and Example 1 is that: the Staphylococcus aeruginosa raw powder, Phanerochaete chrysosporium raw powder, and nitrite oxidizing bacteria raw powder used are not carbon-loaded, and the bacterial liquid obtained by pre-culturing in step S1 of Culture Example 1 is directly dried at room temperature and then crushed into fine powder to obtain functional microbial inoculant raw powders that are not carbon-loaded: Staphylococcus aeruginosa raw powder that is not carbon-loaded, Phanerochaete chrysosporium raw powder that is not carbon-loaded, and nitrite oxidizing bacteria raw powder that is not carbon-loaded are respectively obtained.

[0089] Experimental testing

[0090] Select a test field (4m*5m), crush 10.0kg of wheat straw into 5cm small segments and evenly spread them in the field, and evenly spread the straw compost provided by Examples 1 to 8 in the field with the straw laid at a dosage of 2kg per mu, turn the compost to make the straw and the straw compost evenly mixed, and control the initial humidity of the fermented material between 55% and 65%, which is conducive to the growth of microorganisms and avoids anaerobic fermentation caused by excessive moisture, so as to test the performance of the straw compost provided by Examples 1 to 8; during this period, monitor and adjust the pH value of the fermented material to 6.5-7.5 (if necessary, add an appropriate amount of lime or potassium dihydrogen phosphate and other regulators for adjustment); turn the pile every 3 days to promote oxygen to enter the pile and accelerate microbial activity. After a period of fermentation, when the pile temperature gradually decreases, the color becomes darker, there is no bad smell, and a certain amount of humus is produced, the straw can be considered to be fully decomposed. Specifically, the test items are as follows:

[0091] 1. Detect the maximum temperature and duration of the straw after adding the straw composting agent, and record the above test results in Table 3;

[0092] 2. Detect the weight of the straw before and after 50 days of decomposition, and calculate the weight loss rate of the straw after 50 days of decomposition, and record the above test results in Table 3;

[0093] 3. Return the straw after 50 days of decomposition with the straw composting agent to the field, observe the growth of pests and weeds, and detect the pest and weed rate, and record the above test results in Table 3;

[0094] 4. After 50 days of straw composting, the straw was returned to the field and the organic carbon content in the soil (0-20 cm soil layer) was tested to evaluate the carbon fixation effect of the straw composting agent after returning the straw to the field. The test results are recorded in Table 4.

[0095] 5. After 50 days of composting with straw composting agent, the straw was returned to the field. The organic matter, available phosphorus and quick-acting potassium content in the soil were tested according to "Bio-organic Fertilizer (NY884-2012)" to evaluate the effect of returning the straw to the field and applying straw composting agent to improve the soil stabilization. The test results are recorded in Table 5.

[0096] Table 3 Summary of the test results of straw composting agents for comparative examples 1 to 8

[0097]

[0098] From the results in Table 3, it can be seen that the performance of the straw composting agents provided by Comparative Examples 1 to 8 is inferior to that of Example 1. Compared with the blank control group, the maximum temperature of Example 1 increased by 25°C, the temperature duration was extended by 7 days, the weight loss rate after composting increased by 42%, and the pest and weed rate decreased by 10.2%.

[0099] Compared with Example 1, the straw decomposing agents provided by Comparative Examples 1 to 3, which added two strains, were inferior in performance. For Comparative Examples 1 to 3, the highest temperatures were 66°C, 64°C, and 58°C, respectively, and the temperature durations were 8 days, 7 days, and 7 days, respectively. The weight loss rates after decomposition were 60%, 57%, and 44%, respectively, and the rates of pests and diseases were 1.3%, 1.8%, and 4.8%, respectively. The straw decomposing agents provided by Comparative Example 4, which only added the original powder of nitrite oxidizing bacteria, and Comparative Example 5, which added the original powder of Phanerochaete chrysosporium, were inferior in performance to Example 1. The highest temperatures of Comparative Examples 4 to 5 were 49°C and 55°C, respectively, and the temperature durations were 4 days and 5 days, respectively. The weight loss rates after decomposition were 25% and 28%, respectively, and the rates of pests and diseases were 6.1% and 5.3%, respectively. In Comparative Example 6, no nitrification inhibitor and EM bacteria were added, the maximum temperature was 50°C, the temperature duration was 5 days, the weight loss rate after decomposition was 22%, and the pest rate was 8.7%; compared with Example 1, the maximum temperature dropped by 20°C, the temperature duration was shortened by 5 days, the weight loss rate after decomposition was reduced by 40%, and the pest rate was increased by 8.4%. In Comparative Example 7, no composite functional microbial agent powder was added at all, the maximum temperature was 48°C, the temperature duration was 3 days, the weight loss rate after decomposition was 19%, and the pest rate was 7.8%; compared with Example 1, the maximum temperature dropped by 22°C, the temperature duration was shortened by 7 days, the weight loss rate after decomposition was reduced by 43%, and the pest rate was increased by 7.5%. In Comparative Example 8, the functional microbial agent powder added was not carbon-loaded, and compared with Example 1, the maximum temperature dropped by 2°C, the temperature duration was shortened by 1 day, the weight loss rate after decomposition was reduced by 1%, and the pest rate was increased by 0.7%.

[0100] In comparative examples 1 to 5, as the number of strains decreases, the maximum temperature shows a clear downward trend. At the same time, the gradual increase in the pest and weed rate shows that the synergistic effect of multiple strains has a positive effect on inhibiting the growth of harmful organisms. In particular, the pest and weed rate of comparative examples 4 to 5 is the highest, which further illustrates that the effect of adding only two strains or a single strain of composting agent is relatively limited in terms of increasing the temperature of the pile and promoting the decomposition of straw compared to the composting agent of the three strains. The original powder of the composite functional microbial agent is an indispensable key component in the process of straw composting. It can not only effectively increase the temperature of the pile, extend the duration of high temperature, and promote the rapid decomposition and composting of straw, but also effectively inhibit the survival of pathogens, pests and weed seeds through its rich microbial community and synergistic mechanism. The lack of EM bacteria in comparative example 6 directly reduces the diversity of microbial communities in the pile. It directly causes the pile environment to be unfavorable for the growth of beneficial microorganisms, thereby being unable to effectively inhibit the survival of pathogens, pests and weed seeds. In addition, due to the reduction in the diversity of the microbial community, the heat generated during its reproduction process is also reduced accordingly, resulting in the inability of the fermentation material temperature of Comparative Example 6 to rise more significantly. Specifically, in Example 1, when the maximum temperature reached 70°C and lasted for 10 days, the treatment group showed significant performance advantages compared with other treatment groups, indicating that there is a synergistic warming effect between the three strains, and the high temperature lasts for a long time. Under this condition, the decomposition rate of the straw is extremely fast, and the composting effect is particularly significant. In addition, the incidence rate of pests and diseases in Example 1 is only 0.3%, which is much lower than that of other treatment groups, further proving that the composting agent can not only efficiently promote the decomposition of straw, but also effectively inhibit the occurrence of pests and diseases.

[0101] Table 4 Summary of the experiment on carbon fixation effect of applying straw compost when returning straw to the field

[0102] test <![CDATA[Organic carbon storage (t·hm -2 )]]> Increase Blank control 14.5±0.26c - Example 1 22.2±0.55a 53.10％ Comparative Example 1 20.7±0.13a 42.76％ Comparative Example 2 21.1±0.06a 45.52％ Comparative Example 3 21.3±0.66a 46.90％ Comparative Example 4 20.0±0.24a 37.93％ Comparative Example 5 19.8±0.06a 36.55％ Comparative Example 6 19.1±0.36ab 31.72％ Comparative Example 7 17.2±0.20bc 18.62％ Comparative Example 8 17.5±0.13b 20.69％

[0103] Soil carbon sequestration is mainly achieved by reducing soil carbon pool decomposition and increasing soil carbon pool input. The average soil organic carbon storage in each treatment group in the 0-20cm soil layer increased by 18.62%-53.10% compared with the blank control, especially in Example 1. In particular, in Comparative Examples 7 and 8, which were not loaded with biochar, the organic carbon storage was only 17.2t·hm -2 、17.5t·hm -2，Compared with Example 1, the average soil organic carbon reserves decreased by 34.48% and 32.41%. Example 1 has an advantage in increasing the organic carbon reserves in the surface soil. The porosity and large specific surface area of ​​biochar can adsorb soil organic carbon, isolate microorganisms and their extracellular enzymes from this part of organic carbon, and slow down the decomposition of organic carbon; the returned straw enters the rice field as exogenous carbon, and is decomposed and utilized by soil microorganisms, and part of it is fixed in the soil carbon pool in the form of soil aggregate organic matter components and microbial biomass carbon. In particular, no nitrification inhibitor was added in Comparative Example 6, and the organic carbon reserves were only 31.72 t·hm -2 Compared with Example 1, the average soil organic carbon reserve decreased by 20.38%. Nitrification inhibitors indirectly promote carbon fixation by slowing down the nitrification process and reducing N2O emissions, while nitrite bacteria indirectly affect the carbon fixation process by participating in the nitrification process and affecting the soil nitrogen cycle and improving the absorption and utilization of nitrogen by plants.

[0104] Table 5 Summary of the test results on improving soil stabilization by applying straw compost when returning straw to the field

[0105] test Organic matter (g / kg) Available phosphorus (mg / kg) Available potassium (mg / kg) Blank control 23.6 31.65 164.86 Example 1 27.9 36.12 205.97 Comparative Example 1 24.6 33.36 182.97 Comparative Example 2 26.3 35.24 194.07 Comparative Example 3 25.1 34.08 185.19 Comparative Example 4 24.3 33.12 179.99 Comparative Example 5 24.1 32.89 175.49 Comparative Example 6 25.8 35.32 199.98 Comparative Example 7 23.8 31.32 165.73 Comparative Example 8 26.5 35.61 200.31

[0106] From the results in Table 5, it can be seen that the soil fixation effect of the straw compost provided by Comparative Examples 1 to 8 is not as good as that of Example 1. As the number of strains decreases, the soil fixation effect of the straw compost gradually weakens. Compared with Example 1, the organic matter, available phosphorus, and available potassium contents of Comparative Example 7 were reduced by 4.1 g / kg, 4.8 mg / kg, and 40.24 mg / kg, respectively, indicating that the addition of functional composite microorganisms is beneficial to the improvement of soil fixation.

[0107] Compared with the blank control group, the straw composting agent of Example 1 increased the content of soil organic matter, available phosphorus, and available potassium by 18.22%, 14.12%, and 24.93%, respectively. The test shows that the straw composting agent configured in Example 1 helps to better decompose the straw and increase the nutrient content of the soil.

Claims

1. A straw composting agent, characterized in that: The composition includes the following components by weight: 10-20 parts of corn stalks, 50-60 parts of composite functional microbial agent powder, 10-20 parts of nitrification inhibitor, and 10-20 parts of EM bacteria; The composite functional microbial agent powder is composed of the following single functional microbial agent powders by weight: 20-30 parts of Staphylococcus pseudoxylosus powder, 20-30 parts of Phanerochaete chrysosporium powder and 1-5 parts of nitrite oxidizing bacteria powder; The method for preparing the functional microbial agent raw powder comprises the following steps: S1. Inoculate the functional microbial agent into the composite culture medium, activate and culture for 24 to 48 hours, allow the bacteria to reach the logarithmic growth phase, and preserve the bacterial solution; S2. The bacterial solution obtained in step S1 is mixed with biochar, and after vibration adsorption, the mixture is passed through a 200-mesh sieve, washed, dried, and crushed to obtain a raw powder of a functional microbial agent.

2. The straw composting agent according to claim 1, characterized in that: In step S1, the activation temperature of Staphylococcus pseudoxylosus is 25-30°C, the activation temperature of Phanerochaete chrysosporium is 28-32°C, and the activation temperature of nitrite oxidizing bacteria is 30-35°C; and / or In step S2, the biochar is nitrogen and phosphorus loaded biochar; preferably, the preparation method of the biochar is: first calcining corn stalks to obtain biochar, then adding the biochar to a mixed solution containing urea and diammonium phosphate, ultrasonically treating for 2 hours, drying, and pyrolyzing the solid powder at 600°C for 30 minutes to obtain nitrogen and phosphorus loaded biochar; preferably, the mass ratio of urea, diammonium phosphate and biochar is 2-3:4-5:10; preferably, the bacterial liquid and biochar are mixed in a ratio of 10mL:1g.

3. The straw composting agent according to claim 1, characterized in that: In step S2, the oscillation adsorption conditions are: constant temperature oscillation adsorption at 25-35°C and 160-220 r / min for 24h-48h.

4. The straw composting agent according to claim 1, characterized in that: In step S2, the conditions for calcining corn stalks to obtain biochar are: pyrolysis at 600° C. for 1 hour.

5. The straw composting agent according to claim 1, characterized in that: In step S1, the components of the composite culture medium per liter are: 250-300g glucose, 150-200g soybean meal powder, 100-120g magnesium sulfate, 10-20g corn straw powder, 30-50g potassium dihydrogen phosphate, 8-10g vitamin B1 and the balance water, and the pH of the composite culture medium is 7.

0.

6. The straw composting agent according to claim 5, characterized in that: The particle size of the corn stalk powder is 60-100 mesh sieve.

7. The straw composting agent according to claim 1, characterized in that: The nitrification inhibitor is selected from any one of nitrogen pyridine, dicyandiamide, and 3,4-dimethylpyrazole phosphate.

8. The straw composting agent according to claim 1, characterized in that: The length of the corn stalks is 3-5 cm.

9. Use of the straw composting agent according to any one of claims 1 to 8 in returning straw to the field in situ, fixing carbon and improving soil nutrients.

10. The use according to claim 9, characterized in that: The soil nutrients refer to one or more of organic matter, available phosphorus, and available potassium.

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