Method for improving fermentation quality of silage based on biochar regulation and control

Abstract

The invention relates to the technical field of agriculture, in particular to a method for improving silage fermentation quality based on biochar regulation and control, which comprises the following steps: fermenting a silage raw material added with biochar and cane sugar in a closed environment, the addition amount of the biochar being not less than 2% of the fresh weight of the silage raw material; the addition amount of the sucrose is not less than 2% of the fresh weight of the silage raw material; the fermentation days are more than or equal to 30 days, the pH value of the silage is less than or equal to 4.35, and the total content of lactic acid, acetic acid, propionic acid and butyric acid in the silage is more than or equal to 7.99% of the dry weight of the silage. When the biochar and the cane sugar are used as additives to prepare the silage through fermentation, on one hand, the pH value can be balanced through the addition of the biochar, the situation that the pH value is rapidly reduced possibly due to independent use of the cane sugar is avoided, further production of lactic acid in the later period is inhibited, the acidification process is effectively buffered, and continuous and stable lactic acid generation is promoted; on the other hand, the problems of increase of nutrient substance loss, promotion of generation of byproducts such as acetic acid, reduction of generation of lactic acid and the like when the biochar is independently added are avoided.

Description

Technical Field

[0001] The present invention relates to the field of agricultural technology, and in particular to a method for improving the fermentation quality of silage based on biochar regulation. Background Art

[0002] The storage and transportation process of silage is essentially a secondary processing process of silage raw materials through fermentation to form silage. The core of this process lies in the reproduction and metabolism of microorganisms. The quality and safety of silage are highly dependent on the activities of microorganisms during the fermentation process, which are significantly affected by the formulation of silage additives.

[0003] Silage additives play an important role in improving the preservation quality of silage, and are mainly divided into six categories: homologous fermentation lactic acid bacteria, heterologous fermentation lactic acid bacteria, preparations of the combination of the two, other microbial inoculants, chemical additives and enzyme preparations. At present, the fermentation quality is usually improved by adding the above-mentioned biological and chemical additives, as well as exogenous substrates (such as molasses, etc.) during silage processing. However, these additives have the following disadvantages: 1. The production cost of silage is significantly increased, which in turn affects the overall economic benefits of animal husbandry; 2. The addition of chemical additives or exogenous substrates will significantly change the silage fermentation process, resulting in rapid accumulation of lactic acid in a short period of time, causing a sharp drop in pH, thereby inhibiting the further proliferation of lactic acid bacteria, hindering the continuous production of lactic acid, resulting in a decrease in lactic acid content or prompting lactic acid bacteria to turn to isolactic fermentation, increasing nutrient loss, promoting the production of by-products such as acetic acid, and reducing the production of lactic acid; 3. Due to the immature processing technology and limited types of commercial preparations, the fermentation stability is poor, and its application in silage is still limited. It is necessary to further optimize the processing and application of microbial preparations to achieve continuous improvement in silage quality.

[0004] Therefore, there is an urgent need to develop a low-cost and efficient silage processing method to reduce production costs while maintaining or improving feed quality and promote the sustainable development of animal husbandry. Summary of the invention

[0005] In view of the above analysis, the present invention aims to provide a method for improving the fermentation quality of silage based on biochar regulation, so as to improve the fermentation quality of silage and solve at least one of the problems existing in the prior art, such as large nutrient loss, poor fermentation stability and high production cost.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions:

[0007] A method for improving the fermentation quality of silage based on the regulation of biochar additives comprises: fermenting silage raw materials added with biochar and sucrose in a closed environment.

[0008] Preferably, the added amount of the biochar is not less than 2% of the fresh weight of the silage raw material; and the added amount of the sucrose is not less than 2% of the fresh weight of the silage raw material.

[0009] Preferably, the added amount of the biochar is 2% to 4% of the fresh weight of the silage raw material.

[0010] Preferably, the ratio of the amount of biochar added to the amount of sucrose added satisfies: 2:0.8-1.2.

[0011] Preferably, the biochar has a particle size of 0.11 to 0.45 mm and is in powder form.

[0012] Preferably, the specific surface area of ​​the biochar is 20.33 to 85.10 m 2 / g.

[0013] Preferably, the porosity of the biochar is 18.55-25.10%.

[0014] Preferably, the biochar can be prepared by the following process: heating the biochar raw material at 300-600° C. in an inert atmosphere for 1-2 hours, with a heating rate of 5-15° C. / min.

[0015] Preferably, the biochar raw material is woody feed.

[0016] A high-quality silage is prepared by the above-mentioned method for improving the fermentation quality of silage based on biochar regulation, the fermentation days are ≥30 days, the pH of the silage is ≤4.35, and the total acid content of lactic acid + acetic acid + propionic acid + butyric acid in the silage is ≥7.99% of the dry weight of the silage.

[0017] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0018] (1) The present invention uses biochar and sucrose as additives when preparing silage, which has a significant synergistic enhancement effect when fermenting to prepare silage: on the one hand, the addition of biochar can balance the pH value, avoid the rapid decrease in pH value caused by the use of sucrose alone, inhibit the further production of lactic acid in the later stage, and effectively buffer the acidification process. Under the premise of not inhibiting the activity of lactic acid bacteria, sufficient alkaline buffer can be provided to keep the pH value of the fermentation environment within an ideal range, thereby promoting continuous and stable lactic acid production; on the other hand, it avoids the problem that when biochar is added alone, lactic acid bacteria turn to isolactic fermentation, increase nutrient loss, promote the production of by-products such as acetic acid, and reduce the production of lactic acid.

[0019] (2) The silage fermentation of the present invention does not require the addition of additional lactic acid bacteria species. The lactic acid bacteria species that naturally survive on the surface of the silage raw materials are used as the fermentation bacteria species. Different silage raw materials are selected for experiments (there are certain differences in the spontaneous lactic acid bacteria species on the surface of different silage raw materials). The fermentation quality of the silage can achieve a good improvement effect: the biochar pH value detection value is ≥9.93, the silage pH is ≤4.35, and the total acid content is above 7.99% DM (dry weight of silage); compared with the method of adding lactic acid bacteria preparations in the prior art, it can significantly reduce the acetic acid production and the relative lactic acid ratio, and obtain a higher total acid content and lactic acid ratio, the lactic acid content accounts for more than 80% of the total acid, the acetic acid content accounts for less than 15% of the total acid, the lactic acid / acetic acid ratio is 7.2-9.0, and no butyric acid is contained or the butyric acid content accounts for less than 10% of the total acid.

[0020] (3) The present invention uses woody feed as the raw material of biochar. The biochar generated after carbonization of woody feed usually has a higher carbon content and aromatic hydrocarbon components. These characteristics give the biochar higher chemical stability and durability. During the silage fermentation process, wood biochar can provide a stable microenvironment, effectively control humidity and acidity, reduce adverse reactions during the fermentation process, and extend the shelf life of silage products. In addition, the biochar generated from woody feed has a strong structure and rich pores, which is conducive to the adsorption of moisture and volatile organic compounds, inhibiting the growth of harmful microorganisms, and ultimately improving the fermentation quality of silage.

[0021] Other features and advantages of the present invention will be described in the following description, and some advantages may become apparent from the description, or may be understood by practicing the present invention. The purpose and other advantages of the present invention may be realized and obtained through the contents particularly pointed out in the embodiments of the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 These are the infrared characterization spectra of biochars of Example 1 and Comparative Examples 6-8 of the present invention. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0024] About the definition of terms

[0025] Silage additives: Various substances added during the fermentation process of silage to promote the growth of lactic acid bacteria, inhibit harmful microorganisms, improve fermentation quality and feed preservation. Common silage additives include lactic acid bacteria additives, soluble carbohydrates and enzyme preparations.

[0026] Biochar: A carbon-rich material produced by the pyrolysis of organic matter (such as plant residues, crop waste or wood) under anaerobic or oxygen-free conditions.

[0027] On the one hand, the present invention discloses a method for improving the fermentation quality of silage feed based on biochar regulation, comprising: fermenting silage raw materials added with biochar and sucrose in a closed environment.

[0028] It should be noted that the applicant's research found that biochar and sucrose have a significant synergistic enhancing effect as additives when fermenting and preparing silage: on the one hand, the addition of biochar can balance the pH value, avoid the rapid drop in pH value caused by the use of sucrose alone, inhibit the further production of lactic acid in the later stage, and effectively buffer the acidification process. It can provide sufficient alkaline buffer without inhibiting the activity of lactic acid bacteria, so that the pH value of the fermentation environment is maintained within an ideal range, thereby promoting continuous and stable lactic acid production; on the other hand, it avoids the problem that when biochar is added alone, lactic acid bacteria turn to isolactic fermentation, increase nutrient loss, promote the production of by-products such as acetic acid, and reduce the production of lactic acid.

[0029] It should be noted that biochar, as a porous, carbon-rich material, has strong adsorption capacity and good physical and chemical properties. It can improve the physical and chemical environment of silage raw materials and is a key factor in ensuring the microbial safety and stability of biological materials such as forage, feed, and food. By regulating the amount of biochar added, the reproduction and metabolic activities of microorganisms during the fermentation process can be directly affected, thereby regulating the quality of the product. High-quality silage fermentation is the result of the activity of microbial communities dominated by lactic acid bacteria. Therefore, the addition of biochar can effectively regulate the balance of moisture, pH and nutrients in the silage environment, affect the reproduction and metabolism of lactic acid bacteria, and thus improve the quality of fermentation.

[0030] It should be noted that the silage fermentation of the present invention does not require the addition of additional lactic acid bacteria strains. The lactic acid bacteria strains that naturally survive on the surface of the silage raw materials are used as the fermentation strains. Different silage raw materials are selected for experiments (there are certain differences in the spontaneous lactic acid bacteria strains on the surfaces of different silage raw materials). The fermentation quality of the silage can achieve a good improvement effect.

[0031] Specifically, the added amount of the biochar is not less than 2% of the fresh weight of the silage raw material; and the added amount of the sucrose is not less than 2% of the fresh weight of the silage raw material.

[0032] Fresh weight: Fresh weight, referred to as FW, is hereinafter expressed as %FW based on the fresh weight of silage raw materials.

[0033] Dry weight: DW for short. In the following text, the percentage of substances based on the fresh weight of silage raw materials is expressed as %DW.

[0034] It should be noted that the addition of biochar can significantly promote the growth of beneficial bacteria such as Lactobacillus and Enterococcus, thereby increasing the production of lactic acid and inhibiting harmful bacteria such as Pantotheca and Proteus; the addition of sucrose can serve as an easily fermentable carbon source, significantly improving the activity of lactic acid bacteria and accelerating the fermentation process; if the amount of biochar and sucrose added is too small, it is difficult to play the above role.

[0035] Preferably, the biochar is added in an amount of 2% FW to 4% FW.

[0036] Specifically, the added amount of the biochar can be 2.0% FW, 2.2% FW, 2.4% FW, 2.5% FW, 2.6% FW, 2.8% FW, 3.0% FW, 3.2% FW, 3.4% FW, 3.5% FW, 3.6% FW, 3.8% FW or 4.0% FW.

[0037] Preferably, the ratio of the amount of biochar added to the amount of sucrose added satisfies: 2:0.8-1.2.

[0038] Specifically, the ratio of the amount of biochar added to the amount of sucrose added can be: 2:0.8, 0.82, 0.84, 0.85, 0.86, 0.88, 0.9, 0.92, 0.94, 0.95, 0.96, 0.98, 1.0, 1.02, 1.05, 1.06, 1.08, 1.1, 1.12, 1.15, 1.16, 1.18, 1.19 or 1.2.

[0039] It should be noted that the applicant has found that: on the one hand, the ratio of the addition of biochar to the addition of sucrose within a limited range can optimize the fermentation process: sucrose can quickly start fermentation and increase the initial lactic acid production, while the slow-release effect provided by biochar during the fermentation process can extend the fermentation time and ensure that the lactic acid bacteria are still sufficiently active in the later stage. Therefore, the above-mentioned limited ratio of biochar and sucrose can take into account both the early and late stages of fermentation, achieving an overall fermentation optimization effect.

[0040] On the other hand, the ratio of the amount of biochar added to the amount of sucrose added is within a limited range, which can improve the efficiency of resource utilization: this ratio makes the amount of biochar used high enough to give full play to its buffering capacity, while also making the most of sucrose as a fermentation substrate to ensure the efficient reproduction of lactic acid bacteria and the continuous production of lactic acid. This ratio can achieve the best fermentation effect without wasting resources. Specifically, the fermentation is anaerobic fermentation under air-isolated conditions after sealing, and the fermentation temperature is 20 to 30°C.

[0041] Preferably, the fermentation temperature is 20-25°C.

[0042] It should be noted that different temperatures have different effects on the metabolic capacity of anaerobic lactic acid bacteria, and different temperature selections have significant effects on the fermentation quality of silage:

[0043] Under low temperature conditions (below 20°C), the metabolic activity of anaerobic lactic acid bacteria slows down significantly, and the rate of enzymatic reactions decreases, especially affecting metabolic pathways such as arginine and proline, resulting in a decrease in the growth of lactic acid bacteria and the rate of lactic acid production. In this case, the fermentation process becomes slower and may extend the fermentation time of silage. In addition, low temperatures limit the activity of lactic acid bacteria, which may allow other non-lactic acid bacteria microorganisms such as molds and yeasts to dominate, thereby affecting the fermentation quality and resulting in insufficient acidity, poor aroma, and loss of nutrients in silage.

[0044] In the medium temperature range (20℃ to 30℃), the metabolic activity of lactic acid bacteria reaches the best state, producing a large amount of lactic acid, which can quickly reduce the pH value, inhibit the growth of harmful microorganisms, and ensure the quality of silage. For example, at 20℃ and 25℃, the dominant genus is Lactobacillus, while at 30℃, Lactobacillus and Pediococcus coexist. This temperature range not only promotes rapid fermentation, but also helps to retain nutrients and the long-term stability of feed. It is the optimal temperature range for silage fermentation.

[0045] When the temperature rises above 30℃, although the metabolic activity of lactic acid bacteria may be enhanced in a short period of time, producing a large amount of lactic acid, the continuous high temperature environment will bring adverse consequences. High temperature will cause the enzyme activity of lactic acid bacteria to decrease, even leading to bacterial death, and promote the growth of thermophilic microorganisms such as acetogenic bacteria and spoilage bacteria. The metabolites of these microorganisms may cause the silage to be too acidic, produce odor, and even cause corruption, thus seriously affecting the fermentation quality.

[0046] Specifically, before fermentation, the biochar and sucrose in the silage raw materials are added to the target ratio, mixed evenly and then fermented to ensure the best fermentation effect.

[0047] Preferably, the silage raw materials include one or more of woody feed and processed by-products thereof, leguminous forage and processed by-products thereof, gramineous forage and processed by-products thereof, leguminous crops and crops other than gramineous crops and processed by-products thereof, wetland plants and processed by-products thereof, and aquatic plants and processed by-products thereof.

[0048] Preferably, the woody feed is one or more of apple branches, Caragana korshinskii, and Broussonetia pavers; the Gramineae forage is one or more of sweet sorghum and buckwheat straw.

[0049] Preferably, the woody feed is Broussonetia papyrifera L.

[0050] It should be noted that paper mulberry leaves are non-toxic, highly safe, grow rapidly, have excellent production efficiency, and can grow in a variety of soil environments, including poor and arid soil conditions. Therefore, they have wide applicability and are suitable for large-scale development and utilization. Their efficient nutrient conversion and growth-promoting effects make them a potential high-quality resource for solving the shortage of protein raw materials in animal husbandry, and have good economic development prospects.

[0051] At the same time, paper mulberry leaves are rich in nutrients such as protein, calcium, and iron, and can replace traditional feed resources such as alfalfa meal and soybean meal. It has a significant positive effect on the growth performance of non-ruminant animals (such as pigs and chickens), can increase nitrogen deposition rate and the biological value of protein, improve meat quality and immune function; it also shows a high feed utilization efficiency in ruminants.

[0052] It should be noted that the quality of silage fermentation is affected not only by its own chemical content and structure but also by the degree of crushing.

[0053] Preferably, the silage raw material is chopped into 1-2 cm before fermentation.

[0054] Preferably, the particle size of the biochar is 0.11-0.45 mm, and the biochar is in powder form; the specific surface area of ​​the biochar is 20.33-85.10 m 2 / g; the porosity of the biochar is 18.55-25.10%.

[0055] It should be noted that the particle size, properties (porous, fibrous, flaky characteristics), specific surface area and porosity of biochar have a significant impact on the quality of silage fermentation by regulating water adsorption, microbial activity and fermentation environment. Biochar with small particle size, high specific surface area and high porosity can effectively adsorb water, volatile organic compounds and harmful gases, stabilize the fermentation environment, promote the reproduction of lactic acid bacteria, and inhibit the growth of undesirable microorganisms, thereby improving fermentation efficiency and product quality.

[0056] In addition, the alkaline functional groups (such as hydroxyl groups) in biochar can absorb hydrogen ions, alleviate the inhibition of lactic acid bacteria by initial acidification, and optimize the acidity balance. The high stability of the aromatic hydrocarbon components ensures that the biochar can maintain its effect during and after fermentation, providing long-term environmental stability.

[0057] Specifically, the biochar can be prepared by the following process: heating the biochar raw material at 300-600° C. in an inert atmosphere for 1-2 hours, with a heating rate of 5-15° C. / min.

[0058] Preferably, the biochar raw material is paper mulberry.

[0059] It should be noted that woody feed, as a raw material for biochar, has a significant impact on the quality of silage fermentation. The biochar generated after carbonization of woody feed usually has a high carbon content and aromatic hydrocarbon components. These characteristics give the biochar higher chemical stability and durability. During the silage fermentation process, wood biochar can provide a stable microenvironment, effectively control humidity and acidity, reduce adverse reactions during the fermentation process, and extend the shelf life of silage products. In addition, the biochar generated from woody feed has a strong structure and rich pores, which is conducive to the adsorption of moisture and volatile organic matter, inhibiting the growth of harmful microorganisms, and ultimately improving the fermentation quality of silage.

[0060] On the other hand, the present invention discloses high-quality silage prepared by the above method, with the fermentation period being greater than 30 days.

[0061] The pH of the prepared silage is ≤4.35, and the total acid content is above 7.99% DM.

[0062] Preferably, the lactic acid content accounts for more than 80% of the total acid, the acetic acid content accounts for less than 15% of the total acid, the lactic acid / acetic acid ratio is 7.2-9.0, and no butyric acid is contained or the butyric acid content accounts for less than 10% of the total acid.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] Lactic acid content, acetic acid content, lactic acid / acetic acid ratio, pH value and butyric acid content are important indicators for evaluating the quality of silage fermentation. The present invention can significantly improve the fermentation quality of silage by adding biochar to the raw materials for silage fermentation. Compared with silage without the addition of biochar, the addition of biochar can significantly increase the lactic acid content, acetic acid content and total acid content, adjust the lactic acid / acetic acid ratio within the range that can effectively inhibit aerobic exposure, and maintain the pH value of the silage, propionic acid and butyric acid content to meet the requirements of high-quality silage. The feed obtained by silage fermentation of the present invention has the characteristics of high lactic acid content, moderate lactic acid / acetic acid ratio, and low propionic acid and butyric acid content.

[0065] In order to further illustrate the technical solution of the present invention, the following embodiments and comparative examples are further provided:

[0066] Example 1

[0067] This embodiment discloses a high-quality silage, which is prepared by the following method:

[0068] Add biochar regulator and sucrose to the silage raw materials and mix them evenly before fermentation for 30 days;

[0069] Biochar was added at 4% FW.

[0070] The ratio of the amount of biochar added to the amount of sucrose added is 2:1.

[0071] The fermentation is anaerobic fermentation under air-isolation conditions after sealing, and the fermentation temperature is 20-30°C.

[0072] The silage material is Broussonetia papyrifera L.

[0073] Before fermentation, the silage raw materials are chopped into 1-2 cm.

[0074] The particle size of the biochar is 0.22 mm; the property is powder; the specific surface area of ​​the biochar is 57.94 m 2 / g; the porosity of the biochar is 23.34%.

[0075] The biochar can be prepared by the following method: heating 1-2 cm paper mulberry chips at 600° C. in a nitrogen atmosphere for 1-2 hours, with a heating rate of 10° C. / min.

[0076] The pH value of biochar was tested according to the following method: pH value was measured using a pH meter (Mettler FE20 model) at a solid-liquid ratio of 1:20.

[0077] The pH value of the biochar in this example was 9.92.

[0078] The prepared silage has a dry weight of DM=47.60, a pH of 4.27, and a total acid content (mass fraction) of 8.96% DM; the lactic acid content accounts for 85.49% of the total acid, the acetic acid content accounts for 12.28% of the total acid, the lactic acid / acetic acid ratio is 8.18, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0079] Example 2

[0080] This embodiment discloses a high-quality silage, which is prepared by the following method:

[0081] Add biochar regulator and sucrose to the silage raw materials and mix them evenly before fermentation for 30 days;

[0082] Biochar was added at 4% FW.

[0083] The ratio of the amount of biochar added to the amount of sucrose added is 2:0.8.

[0084] The fermentation is anaerobic fermentation under air-isolation conditions after sealing, and the fermentation temperature is 20-30°C.

[0085] The silage material is Broussonetia papyrifera L.

[0086] Before fermentation, the silage raw materials are chopped into 1-2 cm.

[0087] The particle size of the biochar is 0.41 mm; the property is powdery; the specific surface area of ​​the biochar is 20.58 m 2 / g; the porosity of the biochar is 21.17%;

[0088] The biochar can be prepared by the following method: heating 1-2 cm paper mulberry chips at 300° C. in a nitrogen atmosphere for 1-2 hours, with a heating rate of 8° C. / min.

[0089] The biochar index was tested according to the same method as has been disclosed, and the pH value of the biochar in this example was 9.33.

[0090] The prepared silage has a dry weight of DM=45.99, a pH of 4.32, and a total acid content (mass fraction) of 8.05% DM; the lactic acid content accounts for 81.14% of the total acid, the acetic acid content accounts for 13.00% of the total acid, the lactic acid / acetic acid ratio is 7.74, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0091] Example 3

[0092] This embodiment discloses a high-quality silage, which is prepared by the following method:

[0093] Add biochar and sucrose to the silage raw materials and mix them evenly before fermentation for 30 days;

[0094] Biochar was added at 2% FW.

[0095] The ratio of biochar addition to sucrose addition is 2:1.2.

[0096] The fermentation is anaerobic fermentation under air-isolation conditions after sealing, and the fermentation temperature is 20-30°C.

[0097] The silage material is Broussonetia papyrifera L.

[0098] Before fermentation, the silage raw materials are chopped into 1-2 cm.

[0099] The particle size of the biochar is 0.24 mm; the property is powdery; the specific surface area of ​​the biochar is 67.09 m 2 / g; the porosity of the biochar is 21.33%.

[0100] Biochar can be prepared by the following method: 1-2 cm paper mulberry chips are heated at 500°C for 2 hours in a nitrogen atmosphere, with a heating rate of 12°C / min.

[0101] The biochar index was tested according to the same method as has been disclosed, and the pH value of the biochar in this example was 9.41.

[0102] The prepared silage has a dry weight of DM=45.45, a pH of 4.25, and a total acid content (mass fraction) of 8.71% DM; the lactic acid content accounts for 85.65% of the total acid, the acetic acid content accounts for 12.86% of the total acid, the lactic acid / acetic acid ratio is 7.82, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0103] Example 4

[0104] The silage raw material is the woody fodder Caragana korshinskii, which is chopped into 1-2 cm in the same manner as in Example 1, and the other conditions are the same as in Example 1.

[0105] The prepared silage has a dry weight of DM=40.82%, a pH of 4.11, and a total acid content (mass fraction) of 8.23% DM; the lactic acid content accounts for 84.56% of the total acid, the acetic acid content accounts for 11.84% of the total acid, the lactic acid / acetic acid ratio is 8.73, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0106] Example 5

[0107] The silage raw material is sweet sorghum, a herbaceous feed, which is chopped into pieces of 1 to 2 cm in the same manner as in Example 1, and the other conditions are the same as in Example 1.

[0108] The prepared silage has a dry weight of DM=30.47%, a pH of 4.13, and a total acid content (mass fraction) of 8.03% DM; the lactic acid content accounts for 80.70% of the total acid, the acetic acid content accounts for 13.92% of the total acid, the lactic acid / acetic acid ratio is 7.28, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0109] Example 6

[0110] The biochar raw material is woody fodder apple branches, which are chopped into 1-2 cm in the same manner as in Example 1, and the other conditions are the same as in Example 1.

[0111] According to the same method as has been disclosed, the biochar index was tested. The pH value of the biochar in this embodiment was 8.26. The particle size of the biochar was 0.32 mm and the property was powder. The specific surface area of ​​the biochar was 63.24 m 2 / g; the porosity of the biochar is 21.28%.

[0112] The prepared silage has a dry weight of DM=46.00, a pH of 4.17, and a total acid content (mass fraction) of 8.25% DM; the lactic acid content accounts for 81.60% of the total acid, the acetic acid content accounts for 12.78% of the total acid, the lactic acid / acetic acid ratio is 7.68, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0113] Comparative Example 1

[0114] Compared with Example 1, no sucrose and biochar were added, and other conditions were the same as Example 1.

[0115] The prepared silage has a dry weight of DM=45.98, a pH of 4.10, and a total acid content (mass fraction) of 7.47% DM; the lactic acid content accounts for 80.13% of the total acid, the acetic acid content accounts for 16.60% of the total acid, the lactic acid / acetic acid ratio is 5.16, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0116] Comparative Example 2

[0117] Relative to Example 1, no sucrose was added, and the other conditions were the same as in Example 1.

[0118] The prepared silage has a dry weight of DM=45.92, a pH of 4.56, and a total acid content (mass fraction) of 8.40% DM; the lactic acid content accounts for 60.95% of the total acid, the acetic acid content accounts for 24.76% of the total acid, the lactic acid / acetic acid ratio is 3.96, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0119] Comparative Example 3

[0120] Relative to Example 1, no biochar was added, and other conditions were the same as Example 1.

[0121] The prepared silage has a dry weight of DM=44.47, a pH of 4.02, and a total acid content (mass fraction) of 7.67% DM; the lactic acid content accounts for 80.88% of the total acid, the acetic acid content accounts for 17.34% of the total acid, the lactic acid / acetic acid ratio is 5.00, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0122] Comparative Example 4

[0123] When preparing silage, the amount of biochar added was 0.5% FW, and the other conditions were the same as in Example 1.

[0124] The prepared silage has a dry weight of DM=45.94, a pH of 4.08, and a total acid content (mass fraction) of 7.54% DM; the lactic acid content accounts for 82.37% of the total acid, the acetic acid content accounts for 15.21% of the total acid, the lactic acid / acetic acid ratio is 5.18, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0125] Comparative Example 5

[0126] When preparing silage, the biochar addition amount was 6% FW, and the other conditions were the same as in Example 1.

[0127] The prepared silage has a dry weight of DM=46.35, a pH of 4.53, and a total acid content (mass fraction) of 9.11% DM; the lactic acid content accounts for 79.35% of the total acid, the acetic acid content accounts for 19.21% of the total acid, the lactic acid / acetic acid ratio is 4.26, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0128] Comparative Example 6

[0129] Biochar was obtained by heating the same paper mulberry raw material in Example 1 for 2 h at 700° C. in a nitrogen atmosphere. The heating rate was 10° C. / min, and the other conditions were the same as in Example 1.

[0130] According to the same method as has been disclosed, the biochar index was tested. The pH value of the biochar in this embodiment was 10.45. The particle size of the biochar was 0.21 mm. The biochar was in powder form. The specific surface area of ​​the biochar was 58.66 m 2 / g; the porosity of the biochar is 23.56%.

[0131] The prepared silage has a dry weight of DM=46.50, a pH of 4.22, and a total acid content (mass fraction) of 9.50% DM; the lactic acid content accounts for 77.47% of the total acid, the acetic acid content accounts for 22.21% of the total acid, the lactic acid / acetic acid ratio is 3.60, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0132] Comparative Example 7

[0133] Biochar was obtained by heating the same paper mulberry raw material in Example 1 for 2 h at 250° C. in a nitrogen atmosphere. The heating rate was 10° C. / min, and the other conditions were the same as in Example 1.

[0134] According to the same method as has been disclosed, the biochar index was tested. The pH value of the biochar in this embodiment was 7.47. The particle size of the biochar was 0.51 mm. The biochar was in powder form. The specific surface area of ​​the biochar was 16..14 m 2 / g; the porosity of the biochar is 16.31%.

[0135] The prepared silage has a dry weight of DM=47.91, a pH of 4.16, and a total acid content (mass fraction) of 7.63% DM; the lactic acid content accounts for 78.90% of the total acid, the acetic acid content accounts for 19.92% of the total acid, the lactic acid / acetic acid ratio is 4.38, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0136] Comparative Example 8

[0137] The raw material of biochar is buckwheat straw, which is chopped into 1-2 cm in the same way as in Example 1, and the other conditions are the same as in Example 1.

[0138] According to the same method as has been disclosed, the biochar index was tested. The pH value of the biochar in this embodiment was 9.27. The particle size of the biochar was 0.08 mm. The biochar was in powder form. The specific surface area of ​​the biochar was 92.32 m 2 / g; the porosity of the biochar is 17.88%.

[0139] The prepared silage has a dry weight of DM=47.88, a pH of 4.23, and a total acid content (mass fraction) of 8.42% DM; the lactic acid content accounts for 74.22% of the total acid, the acetic acid content accounts for 24.82% of the total acid, the lactic acid / acetic acid ratio is 3.19, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0140] Comparative Example 9

[0141] The bacterial strain used was homologous fermentative lactic acid bacteria (Lactobacillus plantarum 360) purchased from Sichuan Gaofuji Biotechnology Co., Ltd. on the market, and the biochar and sucrose in Example 1 were replaced with the same mass, and the other conditions were the same as in Example 1.

[0142] The prepared silage has a dry weight of DM=41.16, a pH of 4.13, and a total acid content (mass fraction) of 9.35% DM; the lactic acid content accounts for 84.50% of the total acid, the acetic acid content accounts for 12.94% of the total acid, the lactic acid / acetic acid ratio is 7.63, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0143] Comparative Example 10

[0144] The strain used was a heterologous fermentation-specific lactic acid bacterium (Lactobacillus bushi 225) purchased from Sichuan Gaofuji Biotechnology Co., Ltd. on the market, which replaced the biochar and sucrose in Example 1 with the same mass, and the other conditions were the same as in Example 1.

[0145] The prepared silage has a dry weight of DM=46.33, a pH of 4.55, and a total acid content (mass fraction) of 9.01% DM; the lactic acid content accounts for 66.15% of the total acid, the acetic acid content accounts for 33.85% of the total acid, the lactic acid / acetic acid ratio is 1.95, and does not contain butyric acid or the butyric acid content accounts for less than 10% of the total acid.

[0146] The test results of preparing biochar and silage in the examples and comparative examples are shown in the following table:

[0147] The pH value of the biochar prepared in Examples 1-6 is ≥9.93, the silage pH is ≤4.35, and the total acid content is above 7.99% DM; the lactic acid content accounts for more than 80% of the total acid, the acetic acid content accounts for less than 15% of the total acid, the lactic acid / acetic acid ratio is 7.2-9.0, and no butyric acid is contained or the butyric acid content accounts for less than 10% of the total acid.

[0148] By comparing Example 1 and Comparative Examples 1-3, it can be seen that compared with the preferred embodiment within the limited range of the present invention, the proportion of acetic acid content in the total acid in Comparative Examples 1-3 is significantly increased (from 12.28 to greater than 16.60), and the lactic acid / acetic acid ratio is significantly decreased (from 8.18 to less than 5.16).

[0149] By comparing Example 1, Comparative Examples 4 and 5, it can be seen that compared with the preferred embodiment within the limited scope of the present invention, the proportion of acetic acid content in total acid in Comparative Examples 4 and 5 increased significantly (from 12.28 to greater than 15.21), and the lactic acid / acetic acid ratio decreased significantly (from 8.18 to less than 4.26); too little biochar is difficult to play a corresponding role; too much biochar makes the ratio of biochar and sucrose unbalanced. Although the total organic acid content (9.11) is increased in the early and middle stages, in the later stage, due to the lack of sucrose, the lactic acid bacteria undergo heterotypic fermentation, which reduces the proportion of lactic acid and increases the proportion of acetic acid.

[0150] By comparing Example 1, Examples 6 and 7, it can be seen that compared with the preferred embodiments within the defined scope of the present invention, the pH value of the biochar prepared in Example 7 is significantly lower than that in Example 1 (from 9.92 to 7.74), which indicates that the alkaline functional groups (such as hydroxyl groups) in the biochar are reduced; the pH value of the biochar prepared in Example 6 is not significantly increased compared with that in Example 1 (from 9.92 to 10.45), which indicates that after the carbonization temperature exceeds 600°C, the increase in temperature has no significant effect on the increase in the alkaline functional groups (such as hydroxyl groups) in the biochar. At the same time, the proportion of acetic acid content in total acid in Examples 6 and 7 increased significantly (from 12.28 to greater than 19.92), and the lactic acid / acetic acid ratio decreased significantly (from 8.18 to less than 4.38). Figure 1 It can be seen that the hydroxyl states in the biochars of Comparative Example 7 and Example 1 and Comparative Example 6 are different, and there is no significant difference in the hydroxyl states in the biochars of Example 1 and Comparative Example 6. The hydroxyl groups in the biochars of Example 1 and Comparative Example 6 are more conducive to obtaining a lower pH value than those in Example 7.

[0151] Comparing Example 1 and Example 8, it can be seen that the pH value of the biochar prepared in Example 8 is significantly lower than that in Example 1 (from 9.92 to 9.27), which indicates that the alkaline functional groups (such as hydroxyl groups) in the biochar are reduced; the proportion of acetic acid content in the total acid in Example 8 is significantly increased (from 12.28 to greater than 24.82), and the lactic acid / acetic acid ratio is significantly decreased (from 8.18 to less than 3.19). Figure 1It can be seen that the states of methyl, methylene, and carbon-carbon double bonds in the biochars of Comparative Example 8 and Example 1 are different, and the groups in the biochar of Example 1 are more conducive to obtaining a lower pH value than those of Example 8. The biochar generated after carbonization of woody feed usually has a higher carbon content and aromatic hydrocarbon components. These characteristics give the biochar higher chemical stability and durability. For unknown reasons, during the silage fermentation process, wood biochar can provide a stable microenvironment, effectively control humidity and acidity, reduce adverse reactions during the fermentation process, and extend the shelf life of silage products. In addition, the biochar generated from woody feed has a strong structure and rich pores, which is conducive to the adsorption of moisture and volatile organic matter, inhibiting the growth of harmful microorganisms, and ultimately improving the fermentation quality of silage.

[0152] Comparison of Example 1, Comparative Examples 9 and 10 shows that, compared with the preferred embodiment within the scope of the present invention, the proportion of acetic acid content in the total acid in Comparative Examples 9 and 10 significantly increased (from 12.28 to greater than 16.94), and the lactic acid / acetic acid ratio significantly decreased (from 8.18 to less than 5.63). Compared with the method of adding lactic acid bacteria preparation in the prior art, the present invention can significantly reduce the acetic acid production and the relative lactic acid ratio, and obtain a higher total acid content and lactic acid ratio.

[0153]

[0154] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for improving the fermentation quality of silage based on biochar regulation, characterized in that: include: The silage raw materials added with biochar and sucrose are fermented in a closed environment.

2. The method for improving the fermentation quality of silage based on biochar regulation according to claim 1, characterized in that: The added amount of the biochar is not less than 2% of the fresh weight of the silage raw material; the added amount of the sucrose is not less than 2% of the fresh weight of the silage raw material.

3. The method for improving the fermentation quality of silage based on biochar regulation according to claim 2, characterized in that: The added amount of the biochar is 2% to 4% of the fresh weight of the silage raw material.

4. The method for improving the fermentation quality of silage based on biochar regulation according to claim 3, characterized in that: The ratio of the amount of biochar added to the amount of sucrose added satisfies: 2:0.8-1.

2.

5. The method for improving the fermentation quality of silage based on biochar regulation according to claim 4, characterized in that: The particle size of the biochar is 0.11-0.45 mm, and the biochar is in powder form.

6. The method for improving the fermentation quality of silage based on biochar regulation according to claim 5, characterized in that: The specific surface area of ​​the biochar is 20.33-85.10 m 2 / g.

7. The method for improving the fermentation quality of silage based on biochar regulation according to claim 6, characterized in that: The porosity of the biochar is 18.55-25.10%.

8. The method for improving the fermentation quality of silage based on biochar regulation according to claim 7, characterized in that: The biochar is prepared by the following process: the biochar raw material is heated at 300-600° C. in an inert atmosphere for 1-2 hours, and the heating rate is 5-15° C. / min.

9. The method for improving the fermentation quality of silage based on biochar regulation according to claim 8, characterized in that: The biochar raw material is woody feed.

10. A high-quality silage, characterized in that: The silage is prepared by the method for improving the fermentation quality of silage based on biochar regulation as described in any one of claims 1 to 9, the fermentation days are ≥30 days, the pH of the silage is ≤4.35, and the total acid content of lactic acid + acetic acid + propionic acid + butyric acid in the silage is ≥7.99% of the dry weight of the silage.

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