Application of trichoderma decomposition agent in preparation of compost and method for preparing compost

Abstract

The invention discloses application of a trichoderma decomposition agent in preparation of compost and a method for preparing the compost, belongs to the technical field of biological compost, and provides application of the trichoderma decomposition agent in preparation of the compost, the trichoderma decomposition agent comprises trichoderma longibrachiatum T6, trichoderma viride P6 and trichoderma longibrachiatum Lu3; the trichoderma longibrachiatum T6 is preserved in the China General Microbiological Culture Collection Center, the preservation address is No.3, No.1 yard, Beichen West Road, Chaoyang District, Beijing, the preservation number is CGMCC NO.13183, and the preservation date is November 14, 2016. According to the method, the activity of trichoderma in compost is greatly improved by utilizing the trichoderma decomposition agent and adopting an aerobic composting method, and the decomposition speed of straw and cow dung is greatly accelerated by regular ventilation and constant-temperature composting.

Description

Technical Field

[0001] The invention belongs to the technical field of biological composting, and in particular relates to the application of a trichoderma decomposition agent in compost preparation and a method for preparing the compost. Background Art

[0002] Most of the straw in my country is used as fuel, and only a small part is used for composting. Crop straw is an important type of biomass, and its resource utilization is a hot topic in contemporary scientific research. Common agricultural wastes include livestock and poultry manure and crop straw. Livestock and poultry manure refers to solid waste generated in livestock and poultry farming, which contains a large amount of macromolecular organic matter that is not fully utilized, such as about 40% of cellulose in cow dung that is not utilized, and about 30% of crude protein in pig manure. Crop straw refers to the general term for the stem part of mature crops, which is rich in cellulose and lignin. At present, aerobic composting is a treatment process that is used frequently, widely used, and has less harm to the environment in the treatment of livestock and poultry manure and straw tails. The basic technical route of aerobic composting is to first quantitatively mix animal manure, effective microbial populations, and the corresponding conditioning agents of effective microorganisms according to the specified carbon-nitrogen ratio. Secondly, by manipulating the moisture content of the material, the ambient temperature, the pH value of the environment, the carbon-nitrogen ratio, and the oxygen concentration, the target microorganisms in the research object can multiply in large quantities. Finally, the biological characteristics of the target microorganisms are used to transform and decompose macromolecular substances that are difficult to absorb and utilize. Aerobic fermentation is an important method for reducing the amount of straw and recycling it. Through aerobic fermentation, the lignocellulose in the straw can be effectively degraded and humus can be generated at the same time. The products obtained by aerobic fermentation contain a large amount of nutrients and humus, which can be used as fertilizers for agricultural and forestry crops and soil conditioners. Therefore, it is urgent to provide a stable and well-decomposed aerobic composting method. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes the application of Trichoderma decomposition agent in compost preparation and a method for preparing compost. The activity of Trichoderma in compost is greatly increased by using Trichoderma decomposition agent and aerobic composting method. Regular ventilation and constant temperature composting greatly accelerate the decomposition speed of straw and cow dung, and optimize the cellulose degradation rate in cow dung and straw.

[0004] To achieve the above-mentioned object, the present invention provides the use of a Trichoderma decomposition agent in preparing compost, wherein the Trichoderma decomposition agent comprises Trichoderma longibrachiatum T6, Trichoderma viride P6 and Trichoderma longibrachiatum Lu3; the Trichoderma longibrachiatum T6 is deposited in the General Microbiological Center of China National Committee for the Preservation of Microbiological Cultures, with a preservation address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, a preservation number of CGMCCNO.13183, and a preservation date of November 14, 2016.

[0005] Preferably, the preparation method of the Trichoderma decomposition agent is:

[0006] Long branch Trichoderma T6, green Trichoderma P6 and long branch Trichoderma Lu3 were mixed in a volume ratio of 2:1:1 to obtain a seed mixture, and then the seed mixture was inoculated into microcrystalline cellulose culture medium with an inoculum amount of 2% by volume, and cultured at 26°C, light for 12h / d, and 180rpm for 3d to obtain the Trichoderma decomposition agent.

[0007] Further preferably, the effective viable bacteria count of the long-branch Trichoderma T6 bacterial liquid in the Trichoderma decomposition agent is 1×10 5 cfu / mL, the effective viable count of Trichoderma viride P6 bacterial solution was 5×10 3 cfu / mL, the effective viable count of Trichoderma longifolia Lu3 liquid was 5×10 3 cfu / mL.

[0008] Preferably, the compost is prepared using livestock manure and crop straw as raw materials.

[0009] The present invention also provides a method for preparing compost using the Trichoderma decomposition agent, comprising the following steps:

[0010] (1) Mixing livestock manure and crop straw to obtain compost matrix;

[0011] (2) inoculating the Trichoderma decomposition agent into the compost substrate obtained in step (1), and aerobically fermenting the compost to obtain decomposed compost.

[0012] Preferably, the livestock manure and crop straw in step (1) are mixed at a C / N mass ratio of 27:1; and the initial moisture content of the compost matrix in step (1) is 50-60%.

[0013] Preferably, the livestock manure in step (1) is cow manure, and the crop straw in step (1) is corn straw.

[0014] Preferably, the inoculation amount of the Trichoderma decomposition agent in step (2) is calculated based on 3-4% of the volume of the compost substrate.

[0015] Preferably, the temperature of the aerobic fermentation in step (2) is 20-35° C., the aeration time of the aerobic fermentation is 1-2 h / d, and the time of the aerobic fermentation is 18-22 d.

[0016] The invention also provides the method for preparing compost and the obtained mature compost.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects:

[0018] The invention proposes the application of a Trichoderma decomposition agent in compost preparation and a method for preparing compost. The Trichoderma decomposition agent is used to greatly increase the activity of Trichoderma in the compost by adopting an aerobic composting method. Regular ventilation and constant temperature composting greatly accelerate the decomposition speed of straw and cow dung, optimize the cellulose degradation rate in cow dung and straw, and aerobic fermentation is an important method for straw reduction and resource utilization. Through aerobic fermentation, the wood cellulose in the straw can be effectively degraded and humus can be generated at the same time. The product obtained by aerobic fermentation contains a large amount of nutrients and humus, which can be used as fertilizer for agricultural and forestry crops and soil conditioner.

[0019] The present invention reflects the degree of maturity of the substrate by measuring the content of cellulose in the compost substrate of cow dung straw. The composting fermentation conditions of cow dung straw are optimized, and the mixing ratio of cow dung straw is mixed and loaded according to the C / N ratio of 27:1. The optimal composting conditions are: the inoculation amount of Trichoderma decomposition agent is 3.9%, the initial water content is 59.78%, and the ventilation time is 1.48h / d. The cellulose content of the substrate is 173.19mg / g when the fermentation is 20d, and the cellulose degradation rate is increased by 29.81% compared with that before optimization.

[0020] Description of biological deposit of Trichoderma longibrachiatum T6:

[0021] Depository: General Microbiology Center, China Microbiological Culture Collection Administration;

[0022] Deposit number: CGMCC NO.13183;

[0023] Deposit date: November 14, 2016;

[0024] Taxonomic name: Trichoderma longibrachiatum. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 is the glucose standard curve;

[0027] Figure 2 The effect of the amount of Trichoderma decomposition agent added on the cellulose content in the compost substrate, a, b, c and d in the figure represent significant differences;

[0028] Figure 3 The effect of initial water content on the cellulose content in the compost substrate, a, b, c and d in the figure represent significant differences;

[0029] Figure 4 The effect of aeration time on the cellulose content in compost substrate, a, b, c, d and e in the figure represent significant differences;

[0030] Figure 5 The effect of ambient temperature on the cellulose content in compost substrate, a, b and c in the figure represent significant differences;

[0031] Figure 6 It is the contour diagram of the interaction between the inoculum amount of Trichoderma decomposition agent and the initial water content;

[0032] Figure 7 It is a three-dimensional surface diagram of the interaction between the inoculation amount of Trichoderma decomposition agent and the initial water content;

[0033] Figure 8 This is the contour diagram of the interaction between the inoculum amount of Trichoderma decomposition agent and the aeration time;

[0034] Fig. 9 It is a three-dimensional surface diagram of the interaction between the inoculation amount of Trichoderma decomposition agent and the aeration time;

[0035] Fig.10 is the contour plot of the interaction between initial water content and aeration time;

[0036] Fig.11 It is a three-dimensional surface diagram of the interaction between initial water content and ventilation time. DETAILED DESCRIPTION

[0037] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0038] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0039] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0040] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0041] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0042] Materials used in the present invention: Avicel culture medium: Avicel 10g, urea 0.3g, peptone 0.75g, (NH 4 ) 2 SO 4 1.4g, KH 2 PO 4 2g, MgSO 4 0.06g, CaCl 2 0.06g, trace elements (CoCl 2 6H 2 O 0.0037g, FeSO 4 7H 2 O0.005g, ZnSO 4 7H 2 O 0.0014g, MnSO 4 ·H 2 O 0.0016g), Tween 80 2mL, pH 6.

[0043] Trichoderma viride P6 and Trichoderma longibrachiatum Lu3 are disclosed in the non-patent literature: Efficacy of Trichoderma longibrachiatum SC5 Fermentation Filtrate in Inhibiting the Sclerotinia sclerotiorum Growth and Development in Sunflower. Enchen Li 1, Na Zhu 1, Shuwu Zhang 1,2,*, Bingliang Xu 1,*, Lilong Liu3,4 and Aiqin Zhang.

[0044] Example 1

[0045] Long-branch Trichoderma T6, green Trichoderma P6 and long-branch Trichoderma Lu3 were mixed in a volume ratio of 2:1:1 to obtain a seed mixture, and then the seed mixture was inoculated into microcrystalline cellulose medium at a volume fraction of 2%, and cultured at 26°C, 12h / d of light, and 180rpm for 3d to obtain a Trichoderma decomposition agent (the effective viable count of the long-branch Trichoderma T6 bacterial solution was 1×10 5 cfu / mL, the effective viable count of Trichoderma viride P6 bacterial solution was 5×10 3 cfu / mL, the effective viable count of Trichoderma longifolia Lu3 liquid was 5×10 3 cfu / mL).

[0046] (1) Cow dung and corn straw were mixed at a C / N mass ratio of 27:1 to obtain a compost matrix, and the initial moisture content of the compost matrix was adjusted to 59.78%;

[0047] (2) The Trichoderma decomposition agent was inoculated into the compost substrate, the inoculation amount was calculated as 3.19% of the volume of the compost substrate, and aerobic fermentation was carried out at 28° C. with an aeration time of 1.48 h / d for 20 days to obtain mature compost.

[0048] Example 2

[0049] Long-branch Trichoderma T6, green Trichoderma P6 and long-branch Trichoderma Lu3 were mixed in a volume ratio of 2:1:1 to obtain a seed mixture, and then the seed mixture was inoculated into microcrystalline cellulose medium at a volume fraction of 2%, and cultured at 26°C, 12h / d of light, and 180rpm for 3d to obtain a Trichoderma decomposition agent (the effective viable count of the long-branch Trichoderma T6 bacterial solution was 1×10 5 cfu / mL, the effective viable count of Trichoderma viride P6 bacterial solution was 5×10 3 cfu / mL, the effective viable count of Trichoderma longifolia Lu3 liquid was 5×103 cfu / mL).

[0050] (1) Cow dung and corn straw were mixed at a C / N mass ratio of 27:1 to obtain a compost matrix, and the initial moisture content of the compost matrix was adjusted to 60%;

[0051] (2) The Trichoderma decomposition agent was inoculated into the compost substrate, the inoculation amount was calculated as 4% of the volume of the compost substrate, and aerobic fermentation was carried out at 28° C. with an aeration time of 1 h / d for 20 days to obtain mature compost.

[0052] Example 3

[0053] Long-branch Trichoderma T6, green Trichoderma P6 and long-branch Trichoderma Lu3 were mixed in a volume ratio of 2:1:1 to obtain a seed mixture, and then the seed mixture was inoculated into microcrystalline cellulose medium at a volume fraction of 2%, and cultured at 26°C, 12h / d of light, and 180rpm for 3d to obtain a Trichoderma decomposition agent (the effective viable count of the long-branch Trichoderma T6 bacterial solution was 1×10 5 cfu / mL, the effective viable count of Trichoderma viride P6 bacterial solution was 5×10 3 cfu / mL, the effective viable count of Trichoderma longifolia Lu3 liquid was 5×10 3 cfu / mL).

[0054] (1) Cow dung and corn straw were mixed at a C / N mass ratio of 27:1 to obtain a compost matrix, and the initial moisture content of the compost matrix was adjusted to 50%;

[0055] (2) The Trichoderma decomposition agent was inoculated into the compost substrate, the inoculation amount was calculated as 3% of the volume of the compost substrate, and aerobic fermentation was carried out at 20° C. with an aeration time of 1 h / d for 18 days to obtain mature compost.

[0056] Example 4

[0057] Long-branch Trichoderma T6, green Trichoderma P6 and long-branch Trichoderma Lu3 were mixed in a volume ratio of 2:1:1 to obtain a seed mixture, and then the seed mixture was inoculated into microcrystalline cellulose medium at a volume fraction of 2%, and cultured at 26°C, 12h / d of light, and 180rpm for 3d to obtain a Trichoderma decomposition agent (the effective viable count of the long-branch Trichoderma T6 bacterial solution was 1×10 5 cfu / mL, the effective viable count of Trichoderma viride P6 bacterial solution was 5×10 3 cfu / mL, the effective viable count of Trichoderma longifolia Lu3 liquid was 5×10 3 cfu / mL).

[0058] (1) Cow dung and corn straw were mixed at a C / N mass ratio of 27:1 to obtain a compost matrix, and the initial moisture content of the compost matrix was adjusted to 60%;

[0059] (2) The Trichoderma decomposition agent was inoculated into the compost substrate, the inoculation amount was calculated as 4% of the volume of the compost substrate, and aerobic fermentation was carried out at 35° C. with an aeration time of 2 h / d for 22 days to obtain mature compost.

[0060] Example 5

[0061] Long-branch Trichoderma T6, green Trichoderma P6 and long-branch Trichoderma Lu3 were mixed in a volume ratio of 2:1:1 to obtain a seed mixture, and then the seed mixture was inoculated into microcrystalline cellulose medium at a volume fraction of 2%, and cultured at 26°C, 12h / d of light, and 180rpm for 3d to obtain a Trichoderma decomposition agent (the effective viable count of the long-branch Trichoderma T6 bacterial solution was 1×10 5 cfu / mL, the effective viable count of Trichoderma viride P6 bacterial solution was 5×10 3 cfu / mL, the effective viable count of Trichoderma longifolia Lu3 liquid was 5×10 3 cfu / mL).

[0062] (1) Cow dung and corn straw were mixed at a C / N mass ratio of 27:1 to obtain a compost matrix, and the initial moisture content of the compost matrix was adjusted to 55%;

[0063] (2) The Trichoderma decomposition agent was inoculated into the compost substrate, the inoculation amount was calculated as 3.5% of the volume of the compost substrate, and aerobic fermentation was carried out at 26° C. with an aeration time of 1.5 h / d for 20 days to obtain mature compost.

[0064] Experimental example

[0065] 1 Materials and methods

[0066] 1.1 Test materials

[0067] Long-branch Trichoderma T6, green Trichoderma P6 and long-branch Trichoderma Lu3 were mixed in a volume ratio of 2:1:1 to obtain a seed mixture, and then the seed mixture was inoculated into microcrystalline cellulose medium at a volume fraction of 2%, and cultured at 26°C, 12h / d of light, and 180rpm for 3d to obtain a Trichoderma decomposition agent (the effective viable count of the long-branch Trichoderma T6 bacterial solution was 1×10 5 cfu / mL, the effective viable count of Trichoderma viride P6 bacterial solution was 5×10 3 cfu / mL, the effective viable count of Trichoderma longifolia Lu3 liquid was 5×10 3 cfu / mL).

[0068] Cow dung (collected from a dairy farm in Honggu District, Lanzhou City) and corn stalks.

[0069] 1.2 Test methods

[0070] 1.2.2 Compost preparation

[0071] The compost material (Table 1) was prepared according to the C / N ratio of 27:1, the base material moisture content was set to 60%, and the Trichoderma decomposition agent was mixed with the compost base according to 2% of the volume of the compost, and the control was added with the same amount of sterile water. The initial composting condition was 20℃, and the aeration time was 1h / d.

[0072] Table 1 Properties of compost raw materials

[0073] Material Total nitrogen Full Carbon C / N Cow dung 2.17 39 15.4 Corn stalks 0.84 37.74 46

[0074] 1.2.3 Determination of cellulose content in compost matrix

[0075] The cellulose content in the compost matrix was determined using the Solebow cellulose content detection kit.

[0076] 1.2.3.1 Extraction of sample cellulose

[0077] Refer to the instructions of the Solebow cellulose content detection kit to extract the sample cellulose.

[0078] 1.2.3.2 Determination of standard curve

[0079] Preheat the spectrophotometer for more than 30 minutes, adjust the wavelength to 620nm, and adjust the zero with distilled water. Dilute the 10mg / mL standard solution with distilled water to 0.09, 0.08, 0.07, 0.05, 0.025, 0.0125, and 0.00625mg / mL standard solutions for use. Add 300μL of the prepared standard solution, 70μL of the working solution (included in the Leybold Cellulose Content Detection Kit), and 630μL of concentrated sulfuric acid to a 1.5mL centrifuge tube, and add 300μL of distilled water as a control. Mix well, place in a 95℃ water bath for 10 minutes (cover tightly to prevent water loss), take out and cool to room temperature, measure the absorbance at 620nm, and use a blank tube as a control.

[0080] 1.2.3.3 Determination of sample cellulase

[0081] Add 300 μL of the sample solution extracted in 1.2.3.1, 70 μL of working solution and 630 μL of concentrated sulfuric acid into a 1.5 mL centrifuge tube. The determination method is the same as 1.2.3.2.

[0082] Cellulose (mg / g) = 22.52X÷W3, X: glucose content (mg / mL), W3: mass of cell wall material (CWM) weighed when extracting cellulose (g).

[0083] 1.3 Single factor optimization of composting conditions on cellulose content

[0084] 1.3.1 Effect of Trichoderma humus composting agent addition on cellulose content of cow dung straw

[0085] In each treatment group of Experimental Design 5, the inoculum amount of the composting agent was 1%, 2%, 3%, 4% and 5% by volume respectively. The other conditions were the same as those in 1.2.2 of this chapter. Compost samples were collected on the 20th day of composting fermentation and their cellulose content was determined.

[0086] 1.3.2 Effect of initial moisture content on cellulose content of cow dung straw

[0087] Composting was carried out according to the conditions in 1.2.2, with the initial moisture content set to 30%, 40%, 50%, 60% and 70% respectively. Compost samples were collected on the 20th day of composting and their cellulose content was determined.

[0088] 1.3.3 Effect of different aeration times on cellulose content of cow dung straw

[0089] Composting was carried out according to the conditions in 1.2.2, with the time periods set to 0.5 h / d, 1 h / d, 1.5 h / d, 2 h / d and 2.5 h / d. Compost samples were collected on the 20th day of composting and their cellulose content was determined.

[0090] 1.3.4 Effect of different temperatures on the cellulose content of cow dung straw

[0091] Composting was carried out according to the conditions in 1.2.2. The temperatures of the composting bins were set to 20°C, 28°C and 35°C respectively. Compost samples were collected on the 20th day of composting and their cellulose content was determined.

[0092] 1.4 Optimization of composting fermentation conditions by response surface analysis

[0093] The response surface optimization was performed using Design-Expert 10 software, with the addition amount of Trichoderma decomposition agent, temperature, and initial moisture content as independent variables, and cellulose content as the response value. A total of 17 experimental treatments were designed using the Box-Behnken response surface method to prepare the Trichoderma decomposition agent, establish the optimal fermentation condition simulation equation, and verify it.

[0094] 2. Results and Analysis

[0095] 2.1 Determination of the standard curve and the content of cellulose in the compost matrix under initial conditions

[0096] Composting was carried out according to the culture conditions in 1.2.2. Compost samples were collected after 20 days. Figure 1 According to the glucose standard curve shown, the cellulose content was determined to be 246.73 mg / g.

[0097] 2.2 Single factor optimization of composting conditions on cellulose content

[0098] 2.2.1 Effect of Trichoderma humus composting agent addition on cellulose content of cow dung straw

[0099] The results are as follows Figure 2 As shown in the figure, the addition of Trichoderma decomposition agent can have a significant effect on the degradation of cellulose. With the increase of the inoculation dose of Trichoderma decomposition agent, the degradation rate of cellulose in the compost gradually increases. When the inoculation amount is 5%, the cellulose content in the compost substrate is 180.69 mg / g. However, when the inoculation amount is greater than 4%, the synergistic effect on the degradation of cellulose is no longer significant. This may be because the growth space of the Trichoderma strain has reached saturation at 4%, so increasing the inoculation amount will only increase the economic cost.

[0100] 2.2.2 Effect of initial moisture content on cellulose content of cow dung straw

[0101] The results are as follows Figure 3 As shown in the figure, the initial moisture content in the substrate directly affects the degradation rate of cellulose. As the moisture content increases, the degradation of cellulose in the substrate gradually accelerates. When the initial moisture content is 60%, the cellulose content in the substrate is the lowest, which is 192.2 mg / g, and it is significantly different from other treatment groups. However, when the moisture content is greater than 60%, the degradation of cellulose in the substrate begins to slow down again.

[0102] 2.2.3 Effect of different aeration times on cellulose content of cow dung straw

[0103] The results are as follows Figure 4 As shown in the figure, the aeration time of composting has a significant effect on the cellulose content in the substrate. With the increase of aeration time, the degradation rate of cellulose in the substrate increases first and then decreases. When the aeration time is 1h / d, the cellulose content in the substrate is the lowest, indicating that the degradation rate of cellulose is also the highest at this time.

[0104] 2.2.4 Effect of different temperatures on cellulose content of cow dung straw

[0105] The results are as follows Figure 5 As shown in the figure, controlling the ambient temperature has a significant effect on the degradation of cellulose during composting. The optimal ambient temperature is 28°C. When the temperature is 35°C, the cellulose content is higher than that at 28°C. This may be because the high temperature environment in the early stage limits the reproduction of the Trichoderma strain, which in turn affects the secretion of cellulase in the strain, resulting in a slower degradation of cellulose. However, since the ambient temperature is difficult to control and the number of constant temperature composting reactors is limited, the response surface optimization test cannot meet the requirements. Therefore, the influence of ambient temperature is eliminated in the response surface design, and the composting conditions are optimized at 20°C.

[0106] 2.3 Optimization of response surface conditions for straw and cow dung composting

[0107] 2.3.1 Response surface design of significant influencing factors

[0108] According to the principle of single factor experiment and Box-Benhnken design, the software Design expert 8.0 was used to conduct response surface analysis experiment. The initial moisture content, inoculation amount of Trichoderma decomposition agent and aeration time were selected as independent variables. 3 factors and 3 levels with a total of 17 center combinations were designed for response surface analysis. The cellulose content in the compost substrate was used as the response value. The center value experiment was repeated 5 times. The design and experimental analysis results are shown in (Tables 2 and 3).

[0109] Table 2 Box-Benhnken test factor level design

[0110]

[0111] Table 3 Optimization design of composting fermentation conditions

[0112]

[0113]

[0114] 2.3.2 Analysis of variance of regression model

[0115] The variance analysis of the predictive regression model showed that the model regression level reached significant, and the inoculation amount of Trichoderma decomposition agent (A), initial water content (B) and aeration time (C) and the interaction of the inoculation amount of Trichoderma decomposition agent (A) and initial water content (B), the inoculation amount of Trichoderma decomposition agent (A) and aeration time (C), and the initial water content (B) and aeration time (C) had the most significant effects on the cellulase activity of Trichoderma decomposition agent (P<0.0001). At the same time, the coefficient of determination of the regression model equation and the correlation between the coefficient of determination of the prediction and the coefficient of determination were good, indicating that the predictive regression model equation had a good fitting and could better predict the optimal fermentation conditions of composting and the cellulose content under the optimal composting conditions. At the same time, among the three significant factors of Trichoderma inoculum (A), initial moisture content (B) and aeration time (C), initial moisture content and Trichoderma inoculum had the most significant effects on compost vitality, followed by aeration time. However, the interaction terms of Trichoderma inoculum (A)-initial moisture content (B) and Trichoderma inoculum (A)-aeration time (C) were not significant (Table 4), and the sum of squares of AB and AC items were small, so they needed to be eliminated and the best prediction equation was obtained for the second regression model fitting analysis (Table 5).

[0116] Table 4 Variance analysis table of regression model

[0117]

[0118]

[0119] Table 5 Model quadratic regression fitting analysis

[0120] source sum of squares Degrees of Freedom Mean Square F-number P-value Model 1.262E+005 7 18030.98 892.38 <0.0001 A-Inoculation amount of composting agent 1490.31 1 1490.31 73.76 <0.0001 B- Initial moisture content 37248.12 1 37248.12 1843.46 <0.0001 C-Ventilation duration 492.82 1 492.82 24.39 0.0008 BC 221.27 1 221.27 10.95 0.0091 <![CDATA[A 2 ]]> 22313.89 1 22313.89 1104.34 <0.0001 <![CDATA[B 2 ]]> 20390.90 1 20390.90 1009.17 <0.0001 <![CDATA[C 2 ]]> 35099.95 1 35099.95 1737.14 <0.0001 Residual 181.85 9 20.21 - - Lack of Fit 128.05 5 25.61 1.90 0.2762 Pure Error 53.80 4 13.45 - - Total deviation 1.264E+005 16 - - - Coefficient of determination 0.9986 - - - - Corrected determination coefficient 0.9974 - - - -

[0121] According to the multivariate regression fitting analysis, the regression equation model between the significant influencing factors of the inoculation amount of the compost (A), initial water content (B) and aeration time (C) and the total cellulase activity of the Trichoderma compost was obtained as follows:

[0122] Y=181.62-13.65A-68.23B+7.85C-7.44BC+72.80A 2 +69.59B 2 +91.30C 2 In the equation, Y is the predicted value of cellulose content in the composting reaction substrate. In addition, the optimal composting conditions and the minimum cellulose content were predicted based on the regression model. The results showed that the optimal composting fermentation conditions were: the inoculation amount of Trichoderma decomposition agent was 3.19%, the initial moisture content was 59.78%, the aeration time was 1.48h / d, and after 20 days of composting, the predicted value of the minimum cellulose content in the substrate was 164.07mg / g.

[0123] 2.3.3 Analysis of interaction effects of significant influencing factors

[0124] The response surface optimization 3D surface map and two-dimensional contour map intuitively reflect the relationship between the experimental factors and the response values, and can comprehensively reflect the interaction between the two factors. The steepness of the 3D surface map reflects the sensitivity of the enzyme activity to changes in fermentation conditions. The larger the slope, the more significant the impact on the test results; the response surface contour map intuitively reflects the impact of each factor on the response value. The center point of the smallest ellipse in the contour line is the lowest point of the response surface. In addition, the shape of the contour line can reflect the strength of the interaction effect. The ellipse indicates that the interaction between the two factors is significant, while the circle is the opposite. The analysis results of the two-dimensional contour map and the 3D surface map show that B (initial moisture content)-C (ventilation time) (such as Fig.10 and Fig.11 ) is close to an ellipse with a large slope, indicating that the interaction between the two factors is significant, while A (inoculation amount of composting agent)-B (initial water content) and A (inoculation amount of composting agent)-C (ventilation time) (such as Figure 6 , Figure 7 , Figure 8 and Fig. 9 ) The slope of the three-dimensional graph is small, the interaction is weak, and the effect on the rate of cellulose degradation is not significant.

[0125] 2.3.4 Verification of optimal fermentation conditions by response surface analysis

[0126] The verification results of the optimal fermentation conditions showed that the predicted value of the optimal cellulose content of the compost substrate was 164.07 mg / g, which was slightly different from the measured value of 173.19 mg / g. Therefore, the established prediction model was reliable. The cellulose content of the compost substrate was 246.73 mg / g before the optimization of composting conditions and fermentation culture. After the response surface optimization, the cellulose degradation rate increased by 29.81%.

[0127] 3 Conclusion and discussion

[0128] Aerobic fermentation is an important method for reducing and recycling straw. By aerobic fermentation, the lignocellulose in the straw can be effectively degraded and humus can be generated at the same time. The product obtained by aerobic fermentation contains a large amount of nutrients and humus, which can be used as fertilizer for agricultural and forestry crops and soil conditioner. Therefore, the aerobic composting method adopted in the present invention greatly increases the activity of Trichoderma in composting, and the application of regular ventilation and constant temperature composting box accelerates the maturity of straw cow dung to the greatest extent.

[0129] The present invention reflects the degree of maturity of the substrate by measuring the content of cellulose in the compost substrate of cow dung straw. The composting fermentation conditions of cow dung straw are optimized based on single factor significance analysis and response surface optimization method. The results show that the mixing ratio of cow dung straw is mixed and loaded according to the C / N ratio of 27:1. After optimization by response surface optimization method, the cellulose content in the 20-day composting fermentation substrate is 164.07 mg / g. The optimal composting conditions are: the inoculation amount of Trichoderma decomposition agent is 3.9%, the initial water content is 59.78%, and the ventilation time is 1.48h / d. After the verification test, the cellulose content of the substrate at 20 days of fermentation is 173.19 mg / g, which is close to the predicted value, and the cellulose degradation rate is increased by 29.81% compared with before optimization.

[0130] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. The application of Trichoderma decomposition agent in preparing compost is characterized in that: The Trichoderma decomposition agent includes Trichoderma longibrachiatum T6, Trichoderma viride P6 and Trichoderma longibrachiatum Lu3; the Trichoderma longibrachiatum T6 is preserved in the General Microbiological Center of China Microbiological Culture Collection Administration, the preservation address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, the preservation number is CGMCCNO.13183, and the preservation date is November 14, 2016.

2. The application according to claim 1, characterized in that: The preparation method of the Trichoderma decomposition agent is: Long branch Trichoderma T6, green Trichoderma P6 and long branch Trichoderma Lu3 were mixed in a volume ratio of 2:1:1 to obtain a seed mixture, and then the seed mixture was inoculated into microcrystalline cellulose culture medium with an inoculum amount of 2% by volume, and cultured at 26°C, light for 12h / d, and 180rpm for 3d to obtain the Trichoderma decomposition agent.

3. The application according to claim 2, characterized in that: The effective viable bacteria count of the long-branched Trichoderma T6 bacterial liquid in the Trichoderma decomposition agent is 1×10 5 cfu / mL, the effective viable count of Trichoderma viride P6 bacterial solution was 5×10 3 cfu / mL, the effective viable count of Trichoderma longifolia Lu3 liquid was 5×10 3 cfu / mL.

4. The use according to claim 1, characterized in that: The compost is prepared with livestock excrement and crop straw as raw materials.

5. A method for preparing compost using the Trichoderma decomposition agent as claimed in claim 1, characterized in that: The following steps are involved: (1) Mixing livestock manure and crop straw to obtain compost matrix; (2) inoculating the Trichoderma decomposition agent into the compost substrate obtained in step (1), and aerobically fermenting the compost to obtain decomposed compost.

6. The method for preparing compost according to claim 5, characterized in that: The livestock manure and crop straw in step (1) are mixed at a C / N mass ratio of 27:1; the initial moisture content of the compost matrix in step (1) is 50-60%.

7. The method for preparing compost according to claim 5 or 6, characterized in that: The livestock manure in step (1) is cow manure, and the crop straw in step (1) is corn straw.

8. The method for preparing compost according to claim 5, characterized in that: The inoculation amount of the Trichoderma decomposition agent in step (2) is calculated based on 3-4% of the volume of the compost substrate.

9. The method for preparing compost according to claim 5, characterized in that: The temperature of the aerobic fermentation in step (2) is 20-35° C., the aeration time of the aerobic fermentation is 1-2 h / d, and the time of the aerobic fermentation is 18-22 d.

10. The mature compost prepared by the method for preparing compost according to any one of claims 5 to 9.

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