A biological agent for accelerating litter decomposition and improving soil fertility, and a preparation method and application thereof

Abstract

The present application relates to the technical field of biological agent preparation, and particularly relates to a biological agent for accelerating litter decomposition and improving soil fertility, a preparation method and application thereof.The biological agent comprises 20-35 parts of microbial inoculum, 15-25 parts of humus, 10-18 parts of porous carrier, 3-8 parts of citric acid chelate salt and 2-5 parts of slow-release agent.The biological agent prepared according to the components of the present application can degrade the content of cellulose, hemicellulose and lignin in litter, and improve the content of organic matter, total nitrogen, total potassium and available phosphorus in soil, thereby providing a basis for effective degradation of litter.

Description

Technical Field

[0001] This invention relates to the field of biological agent preparation technology, and in particular to a biological agent that accelerates the decomposition of litter and improves soil fertility, as well as its preparation method and application. Background Technology

[0002] Litter (such as straw, fallen leaves, and dead branches) is an important component of agroforestry ecosystems, and its decomposition process is a core link in replenishing soil organic matter and cycling nutrients. However, under natural conditions, litter contains a high content of lignocellulose (cellulose and hemicellulose) and has a long decomposition cycle (usually 12 to 18 months), which can lead to delayed nutrient release, slow accumulation of soil organic matter, and may also cause problems such as the proliferation of pests and diseases and soil compaction.

[0003] Currently, the main methods for accelerating litter decomposition include physical crushing, chemical composting agent treatment, and application of microbial agents. Physical crushing is energy-intensive and easily damages soil structure; although chemical composting agents (such as urea and ammonium persulfate) can accelerate decomposition, they easily cause soil nitrogen loss and environmental pollution, and are difficult to sustainably increase soil organic matter content; existing microbial agents are mostly single strains, with limited efficiency in cellulose degradation, and lack functional compatibility related to organic matter synthesis, thus failing to achieve the synergistic effect of "rapid decomposition-efficient carbon sequestration".

[0004] Therefore, developing a biological agent that can efficiently decompose litter, promote humus synthesis, and improve soil fertility has become a key need to solve the problems of resource utilization of agricultural and forestry waste and improvement of soil organic matter. Summary of the Invention

[0005] The purpose of this invention is to provide a biological agent that accelerates the decomposition of litter and improves soil fertility, specifically relating to a biological agent that accelerates the decomposition of litter and improves soil fertility, its preparation method, and its application.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a biological agent that accelerates the decomposition of litter and improves soil fertility, comprising the following components in parts by weight: 20-35 parts microbial inoculant, 15-25 parts humus, 10-18 parts porous carrier, 3-8 parts citric acid chelate, and 2-5 parts slow-release agent.

[0007] Preferably, the microbial agent comprises the following components in parts by weight: 2-4 parts of Bacillus subtilis inoculant, 1-3 parts of Trichoderma longifolia inoculant, 3-5 parts of Bacillus licheniformis inoculant, and 1-2 parts of Pseudomonas aeruginosa inoculant; The initial viable cell concentration of the Bacillus subtilis inoculant is ≥1.0×10¹. 0CFU / g; The initial viable cell concentration of the *Trichoderma longifolia* agent is ≥1.0 × 10¹. 0 CFU / g; The initial viable cell concentration of the Bacillus licheniformis inoculant is ≥1.0×10¹. 0 CFU / g; The initial viable bacterial concentration of the *Pseudomonas aeruginosa* inoculum is ≥1.0 × 10¹. 0 CFU / g.

[0008] Preferably, the humic substance comprises the following components in parts by weight: 5-8 parts biochar, 3-5 parts humic acid; The biochar is prepared by placing litter at a temperature of 350~450℃ for 1~2 hours to obtain the biochar.

[0009] Preferably, the porous carrier comprises components in the following mass ratio: The ratio of diatomaceous earth to attapulgite is 1~3:0.5~1.5.

[0010] Preferably, the citric acid chelate contains iron, zinc, copper, manganese, boron, and molybdenum.

[0011] Preferably, the sustained-release agent comprises the following components in parts by weight: 10-20 parts glycerol, 10-15 parts sucrose, 1-2 parts sodium alginate, 1-3 parts sodium chloride, 60-78 parts water; The sustained-release agent is prepared by mixing glycerol, sucrose, sodium alginate, sodium chloride, and water to obtain the sustained-release agent.

[0012] This invention also provides a method for preparing a biological agent that accelerates the decomposition of litter and improves soil fertility, comprising the following steps: (1) Weigh each component according to the mass fractions of the biological agent described above; (2) Mix humic substances, porous carriers, and citric acid chelate salts to obtain mixture 1; (3) Mix the mixture 1 with the microbial agent, granulate, and dry to obtain granules; (4) The particles are mixed with the sustained-release agent to obtain a biological agent.

[0013] Preferably, the drying is vacuum drying; The drying temperature is 40~50℃, and the drying pressure is 5~10kPa.

[0014] The present invention also provides the application of the biological agent described herein or the biological agent prepared by the method described herein in the degradation of cellulose and / or hemicellulose in litter.

[0015] The present invention also provides the application of the biological agent described herein or the biological agent prepared by the method described herein in accelerating the decomposition of litter and improving soil fertility.

[0016] Beneficial effects

[0017] (1) The biological agent of the present invention can degrade cellulose and hemicellulose in litter and accelerate the decomposition of litter, thereby increasing the content of organic matter in the soil. (2) All raw materials in the biological agent of the present invention are biological sources or natural minerals, with no chemical residues, which meet the requirements of green agriculture and ecological environmental protection, and can realize the resource utilization of agricultural and forestry waste; (3) The preparation method of the biological agent of the present invention is simple, the cost is controllable, and it is suitable for large-scale production. Detailed Implementation

[0018] The following detailed description of the solutions provided by the present invention, in conjunction with the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0019] The Bacillus subtilis, Trichoderma longifolia, Bacillus licheniformis, and Pseudomonas aeruginosa in the embodiments of this invention are all derived from the China General Microbiological Culture Collection Center. The strain number of Bacillus subtilis is CGMCC 1.2416; the strain number of Trichoderma longifolia is CGMCC 3.4291; the strain number of Bacillus licheniformis is CGMCC 1.813; the strain number of Pseudomonas aeruginosa is CGMCC 1.7418; the EM bacteria in the comparative example of this invention were purchased from Jinan Qinghai Chemical Co., Ltd.

[0020] The citric acid chelate salt in this embodiment of the invention was purchased from Shaanxi Rankang Biotechnology Co., Ltd.; the citric acid chelate salt contains ≥4.5% iron, ≥5.5% zinc, ≥2% copper, ≥2.7% manganese, ≥2% boron, and ≥0.4% molybdenum.

[0021] Example 1

[0022] 1. Preparation of microbial inoculants

[0023] (1) Bacillus subtilis inoculum: Bacillus subtilis was inoculated into LB liquid medium and cultured at 37℃ for 24 h to obtain seed culture; the seed culture was then inoculated into LB liquid medium and fermented at 37℃ for 18 h to obtain fermentation broth. The fermentation broth was mixed with a carrier and dried at 37℃ to obtain Bacillus subtilis inoculum. The viable cell concentration of the Bacillus subtilis inoculum was determined to be 3 × 10¹. 0 CFU / g.

[0024] The carrier is prepared by mixing wheat bran, soybean meal, and corn flour in a mass ratio of 7:2:1 to obtain a mixture. The moisture content of the mixture is adjusted to 60%, and the mixture is sterilized at 121℃ for 30 minutes to obtain the carrier.

[0025] (2) Trichoderma longifolia inoculum: Trichoderma longifolia was inoculated into seed culture medium and cultured at 30℃ for 5 days to obtain seed liquid; the seed liquid was inoculated into solid fermentation medium and cultured at 30℃ for 5 days, and then dried at 37℃ to obtain Trichoderma longifolia inoculum. The viable cell concentration of the obtained Trichoderma longifolia inoculum was 1.0×10¹ 0 CFU / g.

[0026] The seed culture medium uses water as a solvent and comprises the following components at the following concentrations: glucose 20 g / L, yeast extract 5 g / L, peptone 5 g / L, KH₂PO₄ 1 g / L, MgSO₄ 7H2O 0.5g / L, pH 6.2.

[0027] The solid fermentation medium is prepared by mixing wheat bran and corn residue in a mass ratio of 3:1.

[0028] (3) Bacillus licheniformis inoculum: Bacillus licheniformis was inoculated into LB liquid medium and cultured at 37°C for 24 h to obtain seed culture; the seed culture was then inoculated into LB liquid medium and fermented at 37°C for 18 h to obtain fermentation broth. The fermentation broth was mixed with a carrier and dried at 37°C by forced air drying to obtain Bacillus licheniformis inoculum. The viable cell concentration of the Bacillus licheniformis inoculum was measured to be 2.0 × 10¹. 0 CFU / g.

[0029] The carrier is prepared by mixing wheat bran, soybean meal powder and corn flour in a mass ratio of 7:2:1.

[0030] (4) *Pseudomonas aeruginosa* inoculum: *Pseudomonas aeruginosa* was inoculated into LB liquid medium and cultured at 37°C for 24 h to obtain seed culture; the seed culture was then inoculated into LB liquid medium and fermented at 37°C for 18 h to obtain fermentation broth. The fermentation broth was mixed with a carrier and dried at 37°C to obtain *Pseudomonas aeruginosa* inoculum. The viable cell concentration of the *Pseudomonas aeruginosa* inoculum was determined to be 3.0 × 10¹. 0 CFU / g.

[0031] The carrier is prepared by mixing wheat bran, soybean meal powder and corn flour in a mass ratio of 7:2:1.

[0032] Take 20 kg of Bacillus subtilis inoculant, 20 kg of Trichoderma longifolia inoculant, 50 kg of Bacillus licheniformis inoculant, and 10 kg of Pseudomonas aeruginosa inoculant and mix them evenly to obtain the microbial inoculant.

[0033] 2. Preparation of humus

[0034] Biochar: Larch litter was carbonized at 400℃ for 2 hours to obtain biochar.

[0035] Take 60 kg of biochar and 40 kg of humic acid, mix them evenly, and you will get humus.

[0036] 3. Porous carrier

[0037] Diatomaceous earth and attapulgite were mixed evenly at a mass ratio of 1:1.5 to obtain a porous carrier.

[0038] 4. Sustained-release agents

[0039] Mix 1.5 kg of sodium alginate with 70 kg of water until homogeneous, then add 10 kg of glycerol, 15 kg of sucrose and 2 kg of sodium chloride. Stir at 200 rpm for 2 hours to obtain a slow-release agent.

[0040] 5. Preparation of biological agents

[0041] Take 20 kg of humus, 10 kg of porous carrier, and 8 kg of citric acid chelate salt and mix them evenly to obtain mixture 1.

[0042] Add 30 kg of microbial inoculant to mixture 1, granulate to 4 ± 1 mm particles using a granulator, and dry at 40 °C and 8 kPa to obtain granules. Take 3 kg of slow-release agent and spray it onto the surface of the granules to uniformly coat each particle surface with the slow-release agent, thus obtaining the biological agent.

[0043] Example 2

[0044] 1. Preparation of microbial inoculants

[0045] The Bacillus subtilis inoculant, Trichoderma longifolia inoculant, Bacillus licheniformis inoculant, and Pseudomonas aeruginosa inoculant were prepared according to the method in Example 1.

[0046] Take 40 kg of Bacillus subtilis inoculant, 10 kg of Trichoderma longifolia inoculant, 40 kg of Bacillus licheniformis inoculant, and 15 kg of Pseudomonas aeruginosa inoculant and mix them evenly to obtain the microbial inoculant.

[0047] 2. Preparation of humus

[0048] Biochar: Birch litter is carbonized at 350℃ for 2 hours to obtain biochar.

[0049] Take 80 kg of biochar and 30 kg of humic acid, mix them evenly, and you will get humus.

[0050] 3. Porous carrier

[0051] Diatomaceous earth and attapulgite were mixed evenly at a mass ratio of 3:0.5 to obtain a porous carrier.

[0052] 4. Sustained-release agents

[0053] Mix 2 kg of sodium alginate with 78 kg of water until homogeneous, add 15 kg of glycerol, 12 kg of sucrose and 3 kg of sodium chloride, stir at 200 rpm for 2 hours to obtain a slow-release agent.

[0054] 5. Preparation of biological agents

[0055] Take 15 kg of humus, 18 kg of porous carrier, and 5 kg of citric acid chelate salt and mix them evenly to obtain mixture 1.

[0056] Add 35 kg of microbial inoculant to mixture 1, granulate to 4 ± 1 mm particles using a granulator, and dry at 45 °C and 8 kPa to obtain granules. Take 5 kg of slow-release agent and spray it onto the surface of the granules to uniformly coat each particle surface with the slow-release agent, thus obtaining the biological agent.

[0057] Example 3

[0058] 1. Preparation of microbial inoculants

[0059] The Bacillus subtilis inoculant, Trichoderma longifolia inoculant, Bacillus licheniformis inoculant, and Pseudomonas aeruginosa inoculant were prepared according to the method in Example 1.

[0060] Take 30 kg of Bacillus subtilis inoculant, 30 kg of Trichoderma longifolia inoculant, 30 kg of Bacillus licheniformis inoculant, and 20 kg of Pseudomonas aeruginosa inoculant and mix them evenly to obtain the microbial inoculant.

[0061] 2. Preparation of humus

[0062] (1) Biochar: The litter of Mongolian oak was placed at 450℃ and carbonized for 1.5h to obtain biochar.

[0063] Take 50 kg of biochar and 50 kg of humic acid, mix them evenly to obtain humic matter.

[0064] 3. Porous carrier

[0065] Diatomaceous earth and attapulgite were mixed evenly at a mass ratio of 2:1 to obtain a porous carrier.

[0066] 4. Sustained-release agents

[0067] Mix 1 kg of sodium alginate with 60 kg of water until homogeneous, add 20 kg of glycerol, 10 kg of sucrose and 1 kg of sodium chloride, stir at 200 rpm for 2 hours to obtain a sustained-release agent.

[0068] 5. Preparation of biological agents

[0069] Take 25 kg of humus, 15 kg of porous carrier, and 3 kg of citric acid chelate salt and mix them evenly to obtain mixture 1.

[0070] Add 20 kg of microbial inoculant to mixture 1, granulate to 4 ± 1 mm particles using a granulator, and dry at 45 °C and 8 kPa to obtain granules. Take 2 kg of slow-release agent and spray it onto the surface of the granules to uniformly coat each particle surface with the slow-release agent, thus obtaining the biological preparation.

[0071] Comparative Example 1

[0072] The scheme of Comparative Example 1 was set up according to the method of Example 1, except that no microbial inoculant was added, while the other steps were the same as those of Example 1.

[0073] Comparative Example 2

[0074] The scheme of Comparative Example 2 was set up according to the method of Example 1, except that the composition of the microbial agent was different from that of Example 1, and the microbial agent of Example 1 was replaced by purchased EM agent.

[0075] Comparative Example 3

[0076] EM bacterial agent.

[0077] Comparative Example 4

[0078] The microbial agent of Example 1.

[0079] Experimental Example 1

[0080] Litter from larch trees in Mulan Weichang, Hebei Province, was collected, washed, dried, and pulverized to a particle size of 0.7 ± 0.2 cm. 5 g of pulverized litter was added to each Erlenmeyer flask, and the flasks were randomly divided into seven groups: Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. 0.1 g of the corresponding biological agent prepared for each group was added to each Erlenmeyer flask, along with 200 mL of water. The flasks were labeled and incubated at 37°C in a shaker incubator at 150 rpm. Samples were taken on days 7, 14, 21, and 28 of incubation to determine the content of cellulose, hemicellulose, and lignin in the litter. The degradation rate was calculated.

[0081] The initial content of cellulose in larch litter was 29%, the initial content of hemicellulose was 18%, and the initial content of lignin was 28%.

[0082] Cellulose content was determined using the neutral detergent method. Non-cellulose components in litter were extracted using a neutral detergent, and the remaining residue was dried, weighed, and the cellulose content was calculated.

[0083] The hemicellulose content was determined using the acid detergent method.

[0084] The lignin content was determined using the 72% sulfuric acid hydrolysis method.

[0085] Degradation rate % = (initial content - remaining content) / initial content × 100%.

[0086] The degradation rates of cellulose, hemicellulose, and lignin in litter from different groups under different incubation days are shown in Table 1.

[0087] Table 1. Degradation of cellulose and hemicellulose in litter by different biological agents

[0088] Table 1 shows that the biopharmaceuticals described in Examples 1-3 can improve the degradation rate of cellulose, hemicellulose, and lignin in litter. The main function of the microbial agents in the biopharmaceuticals is to degrade cellulose, hemicellulose, and lignin in litter. Other components in the biopharmaceuticals, such as porous carriers, humic substances, and slow-release agents, can slow down the release of microbial content and provide nutrients for the growth of the strain in the later stages, thereby improving the utilization rate of the strain.

[0089] Experiment Example 2

[0090] The experiment used litter from larch forests in Mulan Weichang, Hebei Province. The litter was randomly divided into six groups: Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and a blank control group. Except for the blank control group, each group received 1 kg of the corresponding biological agent, which was then mixed thoroughly, piled into a 1 cubic meter heap, and water was added to maintain a humidity of 60%, followed by covering with a film. The blank control group was also piled into a 1 cubic meter heap, water was added to maintain a humidity of 60%, covered with a film, and allowed to decompose naturally. The experiment was conducted outdoors from November to February of the following year, with outdoor temperatures below zero degrees Celsius. After 3 months of fermentation, the fermented material from each group was collected, and the contents of lignin, cellulose, and hemicellulose were determined according to the method in Example 1. The degradation rate was calculated. Soil samples were taken from 1 cm of the vicinity of the fermentation pile before and after 3 months of fermentation to detect the organic matter content, available phosphorus content, total nitrogen content, and total potassium content.

[0091] The organic matter content in soil was determined using the potassium dichromate bulk density method; total nitrogen was determined using the Kjeldahl method; available phosphorus was determined using the sodium bicarbonate extraction-molybdenum antimony colorimetric method; and total potassium was determined using the flame photometry method.

[0092] Before composting and fermentation, the soil contained 12.3 g / kg of organic matter, 0.75 g / kg of total nitrogen, 0.81 g / kg of total potassium, and 8.2 mg / kg of available phosphorus.

[0093] The degradation rates of larch litter by different biological agents are shown in Table 2, and the soil nutrient composition is shown in Table 3.

[0094] Table 2 Effects of different biological agents on the degradation rate of larch litter

[0095] As shown in Table 2, under low temperature conditions, the bio-agent prepared in Example 1 can still achieve a degradation rate of 36.2% to 45.8% for cellulose, hemicellulose and lignin in litter, indicating that the bio-agent of the present invention has the characteristic of low temperature resistance.

[0096] Table 3. Changes in soil nutrient composition after treatment with different biological agents.

[0097] Table 3 shows that the biological agent in Example 1 can increase the content of organic matter, total nitrogen, total potassium and available phosphorus in the soil compared with other groups. Organic matter increased by 56.1%, total nitrogen by 44%, total potassium by 44.4% and available phosphorus by 69.5%.

[0098] Experimental Example 3

[0099] The experiment was conducted using litter collected from birch forests in Mulan Weichang, Hebei Province, in a greenhouse at a temperature of 22±2℃.

[0100] The litter was mixed with 1 kg of the biological agent from Example 1 per cubic meter of litter, and water was added to maintain a stack humidity of 60%. After fermentation for 2 months, the contents of cellulose, hemicellulose, and lignin in the litter were measured, and the degradation rate was calculated. The results are shown in Table 4.

[0101] Table 4. Degradation rate of cellulose in birch litter

[0102] It can be seen that the biological agent of the present invention degrades cellulose, hemicellulose and lignin in birch litter by 42.7-52.4% in 2 months.

[0103] As can be seen from the above embodiments, the present invention provides a biological agent for accelerating litter decomposition and improving soil fertility, its preparation method, and its application. The biological agent of the present invention comprises 20-35 parts of microbial inoculant, 15-25 parts of humus, 10-18 parts of porous carrier, 3-8 parts of citrate chelate, and 2-5 parts of slow-release agent. The biological agent prepared according to the components of the present invention can degrade the content of cellulose, hemicellulose, and lignin in litter, and increase the content of organic matter, total nitrogen, total potassium, and available phosphorus in the soil, providing a basis for the effective degradation of litter.

[0104] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A biological agent that accelerates the decomposition of litter and improves soil fertility, characterized in that, The components include the following parts by mass: 20-35 parts microbial inoculant, 15-25 parts humus, 10-18 parts porous carrier, 3-8 parts citric acid chelate, and 2-5 parts slow-release agent.

2. The biological agent according to claim 1, characterized in that, The microbial agent comprises the following components in parts by weight: 2-4 parts of Bacillus subtilis inoculant, 1-3 parts of Trichoderma longifolia inoculant, 3-5 parts of Bacillus licheniformis inoculant, and 1-2 parts of Pseudomonas aeruginosa inoculant; The initial viable cell concentration of the Bacillus subtilis inoculant is ≥1.0×10¹. 0 CFU / g; The initial viable cell concentration of the *Trichoderma longifolia* agent is ≥1.0 × 10¹. 0 CFU / g; The initial viable cell concentration of the Bacillus licheniformis inoculant is ≥1.0×10¹. 0 CFU / g; The initial viable bacterial concentration of the *Pseudomonas aeruginosa* inoculum is ≥1.0 × 10¹. 0 CFU / g.

3. The biological agent according to claim 1, characterized in that, The humus comprises the following components in parts by weight: 5-8 parts biochar, 3-5 parts humic acid; The biochar is prepared by placing litter at a temperature of 350~450℃ for 1~2 hours to obtain the biochar.

4. The biological agent according to claim 1, characterized in that, The porous carrier comprises components in the following mass ratio: The ratio of diatomaceous earth to attapulgite is 1~3:0.5~1.

5.

5. The biological agent according to claim 1, characterized in that, The citric acid chelate contains iron, zinc, copper, manganese, boron, and molybdenum.

6. The biological agent according to claim 1, characterized in that, The sustained-release agent comprises the following components in parts by weight: 10-20 parts glycerol, 10-15 parts sucrose, 1-2 parts sodium alginate, 1-3 parts sodium chloride, 60-78 parts water; The sustained-release agent is prepared by mixing glycerol, sucrose, sodium alginate, sodium chloride, and water to obtain the sustained-release agent.

7. A method for preparing a biological agent that accelerates the decomposition of litter and improves soil fertility, characterized in that, Includes the following steps: (1) Weigh each component according to the mass fractions of the biological agent according to any one of claims 1 to 6; (2) Mix humic substances, porous carriers, and citric acid chelate salts to obtain mixture 1; (3) Mix the mixture 1 with the microbial agent, granulate, and dry to obtain granules; (4) The particles are mixed with the sustained-release agent to obtain a biological agent.

8. The preparation method according to claim 7, characterized in that, The drying process is vacuum drying; The drying temperature is 40~50℃, and the drying pressure is 5~10kPa.

9. The use of the biological agent according to any one of claims 1 to 6 or the biological agent prepared by the preparation method according to any one of claims 7 to 8 in the degradation of cellulose and / or hemicellulose in litter.

10. The application of the biological agent according to any one of claims 1 to 6 or the biological agent prepared by the preparation method according to any one of claims 7 to 8 in accelerating the decomposition of litter and improving soil fertility.

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