Biomass self-heating cultivation material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of agricultural waste resource utilization and biological agriculture, and particularly relates to a biomass self-heating cultivation material and a preparation method and application thereof. The biomass self-heating cultivation material comprises the following components in percentage by weight: 81-96% of a biomass raw material, 2-8% of quick lime, 1-6% of a water-retaining agent and 1-5% of plant ash. The preparation method comprises the following steps: (1) uniformly mixing quick lime, a water-retaining agent and plant ash to obtain a chemical slow-release heating material; (2) adjusting the moisture content of the biomass raw material to be 50-60% to obtain a biomass fermentation material; and (3) uniformly mixing the chemical slow-release heating material with the biomass fermentation material to obtain the biomass self-heating cultivation material. By adopting the chemical slow-release heating material containing the quick lime, the water-retaining agent and the plant ash, the purpose of slow release of heat can be achieved, the heat release stability and heating duration of the cultivation material are remarkably improved, and the yield of edible mushrooms is remarkably increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of resource utilization of agricultural waste and biological agriculture, and particularly relates to a biomass self-heating cultivation material, a preparation method thereof, and an application thereof. Background Art

[0002] The optimum growth temperature of most edible fungi is 28-38 °C. The mycelium has poor resistance to low temperature and is mainly cultivated in summer, which limits its yield. Artificial temperature control is an effective method to increase the yield of edible fungi. The existing artificial temperature control methods generally use physical heating to maintain the temperature of the mushroom house. For example, the invention patent with the publication number CN 103477866A records that heating wires are arranged in the culture material to achieve the purpose of temperature increase. However, the cost of physical heating is relatively high, the operation is cumbersome, and there are also certain safety hazards in heating through methods such as coal stoves and electric heaters.

[0003] Utilizing the heat generated by the natural fermentation of biomass and the chemical reaction of quicklime is a feasible alternative way to increase the temperature in edible fungi cultivation. For example, the invention patent with the publication number CN 112913574A records a self-heating cultivation bottom material for straw mushrooms, which includes the following raw materials in weight percentages: 85-90% Chinese herbal medicine residues, 5-8% soybean meal, and 2-8% quicklime, adopting a biological self-heating method to supply heat to meet the heat demand during the entire growth period of straw mushrooms. The invention patent with the publication number CN 102173949A records a cultivation substrate for straw mushrooms, which is prepared from Chinese herbal medicine residues, rice straw, and a yield-increasing agent containing quicklime, calcium source, etc. The invention patent with the publication number CN106396948A records a substrate for producing edible fungi with low energy consumption using waste such as mushroom residues, which consists of 50-68% mushroom residues, 20-30% cow dung, 2-4% quicklime, and 10-20% peanut shells added. Agricultural wastes such as the mushroom residues of Flammulina velutipes and Pleurotus eryngii and cow dung are fully utilized as cultivation substrates, and the bioheat generated by the fermentation of these substrates is used as a heat source, reducing energy consumption.

[0004] However, the existing self-heating cultivation materials generally have problems such as unstable heat release from the reaction of quicklime, short heat release duration, and the high calcium ion concentration and high alkalinity after the reaction of quicklime affecting the heat production of fermenting bacteria and the growth of edible fungi, resulting in unstable temperature control and reduced yield of edible fungi. Summary of the Invention

[0005] Aiming at the above-mentioned drawbacks and deficiencies existing in the prior art, the purpose of the present invention is to provide a biomass self-heating cultivation material, a preparation method thereof, and an application thereof.

[0006] The purpose of the present invention is achieved through the following technical solutions: A biomass self-heating cultivation material, comprising the following components in weight percentage: Biomass raw materials: 81 - 96%, quicklime: 2 - 8%, water retainer: 1 - 6%, plant ash: 1 - 5%.

[0007] Preferably, the biomass raw material is a mixture of at least one plant biomass such as Chinese herbal medicine residue, sawdust, plant straw, peanut shell, rice husk, cottonseed hull, wheat bran, soybean meal and dehydrated livestock and poultry manure.

[0008] More preferably, the mass ratio of the plant biomass to the dehydrated livestock and poultry manure is 3 - 5:1. The plant biomass can provide sufficient carbon source and growth carrier, and the dehydrated livestock and poultry manure provides rich nitrogen source, phosphorus source, sulfur source and microbial flora. Through the mixing and preparation of the plant biomass and the dehydrated livestock and poultry manure, while achieving a good effect of natural fermentation and heat generation of biomass, it has a good nutritional and structural ratio, and promotes the rapid growth of edible fungi.

[0009] Preferably, the water retainer is any one of polyacrylamide water retainer, acrylamide - acrylate copolymer water retainer, polyacrylate water retainer, acrylate - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer water retainer.

[0010] The main purpose of adding the water retainer in the present invention is to utilize its high water absorption and the performance characteristics of forming hydrogel after water absorption, which can significantly reduce the heat release rate of the reaction between quicklime and water, so as to achieve the purpose of slow heat release, and significantly improve the heat release stability and heat generation duration of the cultivation material.

[0011] More preferably, the water retainer is a polyacrylate water retainer or an acrylate - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer water retainer with a neutralization degree of 30 - 70%.

[0012] Most preferably, the water retainer is an acrylate - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer water retainer with the content of 2 - acrylamide - 2 - methylpropanesulfonic acid monomer being 30 - 70% (molar ratio), which is prepared by the following method: Add acrylic acid into water and neutralize it with alkali to a neutralization degree of 90 - 100% to obtain an acrylate solution, then add 2 - acrylamide - 2 - methylpropanesulfonic acid monomer and stir to mix evenly. The addition amount of 2 - acrylamide - 2 - methylpropanesulfonic acid monomer is 30 - 70% of the total molar amount of acrylic acid and 2 - acrylamide - 2 - methylpropanesulfonic acid. After deoxidizing with nitrogen, add redox initiator and crosslinking agent for copolymerization reaction. After the reaction is completed, spray drying is carried out to obtain acrylate - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer water retainer.

[0013] Preferably, the alkali is ammonia water, potassium hydroxide solution or sodium hydroxide solution.

[0014] Preferably, the redox initiator is a redox initiator composed of ammonium persulfate solution and sodium bisulfite solution.

[0015] Preferably, the crosslinking agent is N,N-methylenebisacrylamide, and the dosage of the crosslinking agent is 0.05% - 0.1% of the total molar amount of acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid.

[0016] Preferably, the temperature of the copolymerization reaction is controlled at 50 - 70 °C, and the time is controlled at 3 - 6 h.

[0017] Water-retaining agents with different monomer compositions and degrees of neutralization have a significant impact on the performance of the self-heating cultivation material of the present invention. The water absorption efficiency of the water-retaining agent depends on the high-concentration hydrophilic groups in its structure. In addition, for polyacrylate water-retaining agents, the degree of neutralization also has a significant impact on the water absorption efficiency. When the degree of neutralization is low, the molecular chain is helical, and the hydrophilic groups are wrapped and cannot be effectively extended, resulting in a low water absorption rate. After neutralization, the carboxylate ions can effectively promote the extension of the molecular chain due to electrostatic repulsion, and the hydrophilic groups are released, thus significantly increasing the water absorption rate. In the present invention, in order to achieve the purpose of slow-release of the heat generated by the chemical reaction of quicklime and water, it is necessary to increase the water absorption rate of the water-retaining agent. In addition, in order to further delay the increase in alkalinity and calcium ion concentration after the reaction of quicklime and water in the cultivation material, the water-retaining agent selected in the present invention needs to further contain acidic groups that react with calcium hydroxide and bind to calcium ions. By screening different types of water-retaining agents on the market, the polyacrylamide water-retaining agent has a good water absorption rate and can achieve a good slow-release effect of the heat generated by the chemical reaction, but it cannot delay the increase in alkalinity and calcium ion concentration of the cultivation material, resulting in poor stability of the heat generated by the natural fermentation of biomass and affecting the growth of edible fungi. The acrylamide-acrylate copolymer water-retaining agent also has a poor effect on delaying the increase in alkalinity and calcium ion concentration of the cultivation material. The polyacrylate water-retaining agent can simultaneously have a good slow-release effect of the heat generated by the chemical reaction and the effect of delaying the increase in alkalinity of the cultivation material when the degree of neutralization is 30 - 70%, but the binding property between the carboxylate group and calcium ion is slightly poor, and its effect of delaying the increase in calcium ion concentration is slightly poor. By further using an acrylate-2-acrylamido-2-methylpropanesulfonic acid copolymer water-retaining agent with a 2-acrylamido-2-methylpropanesulfonic acid monomer content of 30 - 70% (molar ratio), the sulfonic acid groups contained in it have a higher binding stability with calcium ions, and the carboxylate structure contained in it can ensure a good water absorption rate, so it has the best application effect in the self-heating cultivation material of biomass of the present invention.

[0018] The preparation method of the above-mentioned self-heating cultivation material of biomass includes the following steps: (1) Mix quicklime, water-retaining agent and plant ash evenly to obtain a chemically slow-release heat-generating material; (2) Adjust the moisture content of the biomass raw material to 50 - 60% to obtain a biomass fermentation material; (3) Mix the chemical slow-release heating material and the biomass fermentation material evenly to obtain a biomass self-heating cultivation material.

[0019] The application of the above-mentioned biomass self-heating cultivation material in edible mushroom cultivation.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention adopts a chemical slow-release heating material containing quicklime, water-retaining agent and plant ash, which can significantly reduce the heat release rate of the reaction between quicklime and water, so as to achieve the purpose of slow heat release, and significantly improve the heat release stability and heat release duration of the cultivation material.

[0021] (2) By further screening the types of water-retaining agents, the present invention can not only achieve the purpose of slow-release chemical reaction heat release, but also react with and combine with calcium hydroxide generated after the chemical reaction heat release, delay the increase of the alkalinity of the cultivation material and the increase of calcium ion concentration, avoid the influence on the growth of biomass fermentation bacteria, and improve the heat production stability of biomass natural fermentation; at the same time, it can also stabilize the pH value of the cultivation material and slow-release calcium source, further promote the growth of edible mushrooms, and thus significantly improve the yield of edible mushrooms. Description of the Drawings

[0022] Figure 1 It is a temperature change curve graph of the biomass self-heating cultivation material obtained in Examples 1 to 4 and Comparative Example 1 at different days after inoculating Volvariella volvacea.

[0023] Figure 2 It is a temperature change curve graph of the biomass self-heating cultivation material obtained by using potassium polyacrylate water-retaining agents with different neutralization degrees in Example 3 at different days after inoculating Volvariella volvacea. Detailed Embodiments

[0024] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto. Example 1

[0025] A biomass self-heating cultivation material, comprising the following components in weight percentage: Biomass raw material 89%, quicklime 5%, water-retaining agent 3%, plant ash 3%.

[0026] The biomass raw material is a mixture of Chinese herbal medicine residues, sawdust, soybean meal and dehydrated livestock and poultry manure in a mass ratio of 2:1:1:1.

[0027] The water-retaining agent adopts a polyacrylamide agricultural water-retaining agent (purchased from the market).

[0028] The preparation method of the biomass self-heating cultivation material comprises the following steps: (1) Mix quicklime, water-retaining agent and plant ash evenly to obtain a chemically slow-release heating material.

[0029] (2) Adjust the moisture content of the biomass raw material to 50 - 60% to obtain a biomass fermentation material.

[0030] (3) Mix the chemically slow-release heating material and the biomass fermentation raw material evenly to obtain a biomass self-heating cultivation material.

[0031] The application of the biomass self-heating cultivation material obtained in this example in straw mushroom cultivation is as follows: Lay the biomass self-heating cultivation material on the small shed planting ridge with a thickness of 10 cm, ventilate and spray water to control the humidity above 85%, and naturally ferment for 3 days. Then inoculate the straw mushroom strain for cultivation, and record the temperature (measured at the bottom of the cultivation material with a thermometer) change of the biomass self-heating cultivation material at different days after inoculating the straw mushroom. The results are as Figure 1 shown.

[0032] The yield of straw mushrooms per square meter after cultivation in this example is 3.2 kg. Example 2

[0033] A biomass self-heating cultivation material. Compared with Example 1, the water-retaining agent used is acrylamide - potassium acrylate copolymer water-retaining agent. The preparation method of the acrylamide - potassium acrylate copolymer water-retaining agent is as follows: Add acrylic acid to water and neutralize it with potassium hydroxide solution to a neutralization degree of 100% to obtain a potassium acrylate solution. Then add acrylamide monomer and stir to mix evenly. The addition amount of acrylamide monomer is 50% of the total molar amount of acrylic acid and acrylamide monomer. After deoxidizing with nitrogen, add ammonium persulfate oxidant solution and cross-linking agent N,N'-methylenebisacrylamide. The addition amount of N,N'-methylenebisacrylamide is 0.08% of the total molar amount of acrylic acid and acrylamide monomer. Heat up to about 60 °C, and then dropwise add sodium bisulfite reductant solution and keep it warm for copolymerization reaction for 4 h. After the reaction is completed, spray dry to obtain acrylamide - potassium acrylate copolymer water-retaining agent.

[0034] The application of the biomass self-heating cultivation material obtained in this example in straw mushroom cultivation is the same as that in Example 1. Record the temperature (measured at the bottom of the cultivation material with a thermometer) change of the biomass self-heating cultivation material at different days after inoculating the straw mushroom. The results are as Figure 1 shown.

[0035] The yield of straw mushrooms per square meter after cultivation in this example is 3.5 kg. Example 3

[0036] A biomass self-heating cultivation material. Compared with Example 1, the water-retaining agent used is a potassium polyacrylate water-retaining agent, and the preparation method of the potassium polyacrylate water-retaining agent is as follows: Acrylic acid was added to water and neutralized with potassium hydroxide solution to neutralization degrees (molar ratio of neutralized acrylate) of 10%, 30%, 50%, 70% and 100% respectively to obtain acrylic acid / potassium acrylate solution. After deoxygenation with nitrogen, ammonium persulfate oxidant solution and crosslinking agent N,N'-methylenebisacrylamide were added. The addition amount of N,N'-methylenebisacrylamide was 0.08% of the molar amount of acrylic acid. The temperature was raised to about 60 °C, and then sodium bisulfite reducing agent solution was added dropwise for heat preservation copolymerization reaction for 4 h. After the reaction was completed, spray drying was carried out to obtain potassium polyacrylate water-retaining agents with different neutralization degrees.

[0037] The application of the biomass self-heating cultivation materials obtained by using potassium polyacrylate water-retaining agents with different neutralization degrees in the cultivation of straw mushrooms in this example. The specific application steps are the same as those in Example 1. Record the temperature (measuring the temperature at the bottom of the cultivation material with a thermometer) changes of the biomass self-heating cultivation material at different days after inoculating straw mushrooms. The results are as Figure 1 (neutralization degree is 50%) and Figure 2 shown.

[0038] The yield per square meter of the straw mushrooms cultivated with the biomass self-heating cultivation materials obtained by using potassium polyacrylate water-retaining agents with different neutralization degrees in this example is as shown in Table 1 below.

[0039] Table 1

[0040] From Figure 2 and the results in Table 1, it can be seen that as the neutralization degree of the potassium polyacrylate water-retaining agent increases, its slow-release heat effect becomes more significant, and the heat release stability and heat release duration increase significantly. The reason is that the higher the neutralization degree, the higher the water absorption rate, so it can delay the heat release of the reaction between slow-release quicklime and water. However, when the neutralization degree reaches 100%, the yield of straw mushrooms decreases significantly. The reason is that when the neutralization degree of the water-retaining agent is too high, it cannot delay the increase in alkalinity and calcium ion concentration after the reaction between quicklime and water in the cultivation material, which destroys the pH value balance and ion balance of the cultivation material and seriously affects the growth of straw mushrooms. Example 4

[0041] A biomass self-heating cultivation material. Compared with Example 1, the water-retaining agent used is an acrylate-2-acrylamide-2-methylpropanesulfonic acid copolymer water-retaining agent, and the preparation method of the acrylate-2-acrylamide-2-methylpropanesulfonic acid copolymer water-retaining agent is as follows: Acrylic acid was added to water and neutralized with potassium hydroxide solution to a neutralization degree of 100% to obtain a potassium acrylate solution. Then, 2-acrylamide-2-methylpropanesulfonic acid monomer was added and stirred to mix evenly. The addition amount of 2-acrylamide-2-methylpropanesulfonic acid monomer was 50% of the total molar amount of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid monomer. After deoxygenation with nitrogen, ammonium persulfate oxidant solution and crosslinking agent N,N'-methylenebisacrylamide were added. The addition amount of N,N'-methylenebisacrylamide was 0.08% of the total molar amount of acrylic acid and acrylamide monomers. The temperature was raised to about 60 °C, and then sodium bisulfite reductant solution was added dropwise and kept warm for copolymerization reaction for 4 h. After the reaction was completed, it was spray-dried to obtain a potassium acrylate-2-acrylamide-2-methylpropanesulfonic acid copolymer water retaining agent.

[0042] The application of the biomass self-heating cultivation material obtained in this example in straw mushroom cultivation is the same as that in Example 1 in specific application steps. Record the temperature (measuring the temperature at the bottom of the cultivation material with a thermometer) changes of the biomass self-heating cultivation material at different days after inoculating straw mushrooms. The results are as Figure 1 shown.

[0043] The yield of straw mushrooms per square meter after cultivation in this example was 5.8 kg.

[0044] Comparative Example 1 A biomass self-heating cultivation material, compared with Example 1, does not add a water retaining agent, and the rest is the same.

[0045] The temperature (measuring the temperature at the bottom of the cultivation material with a thermometer) changes of the biomass self-heating cultivation material in this comparative example at different days after inoculating straw mushrooms are as Figure 1 shown.

[0046] The yield of straw mushrooms per square meter after cultivation in this comparative example was 1.2 kg.

[0047] From Figure 1 the results, it can be seen that the present invention uses different water retaining agents in combination with quicklime, which can significantly reduce the heat release rate of the reaction between quicklime and water, so as to achieve the purpose of slow heat release, and significantly improve the heat release stability and heat release duration of the cultivation material.

[0048] From the straw mushroom yield data of Examples 1-4 and Comparative Example 1, it can be seen that the addition of the water retainer can significantly increase the straw mushroom yield. Among them, the potassium polyacrylate water retainer with a neutralization degree of 30-70% has a higher yield-promoting effect compared to the polyacrylamide water retainer and the acrylamide-potassium acrylate copolymer water retainer. The reason is that when the neutralization degree is 30-70%, it can simultaneously have a good effect of slow-releasing the heat of chemical reaction and delaying the increase in the alkalinity of the cultivation material. In addition, the yield of the straw mushroom cultivated with the cultivation material obtained by using the acrylate-2-acrylamide-2-methylpropanesulfonic acid copolymer water retainer is further significantly increased compared to the potassium polyacrylate water retainer. The reason is that the sulfonic acid group has a higher binding stability with calcium ions compared to the carboxylic acid group, which can further stabilize the calcium ion concentration in the cultivation material, maintain the calcium ion balance during the growth of the straw mushroom mycelium, and the growth rate is faster, and the yield is significantly increased.

[0049] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A biomass self-heating cultivation material, characterized in that Comprising components with the following weight percentages: biomass raw material 81 - 96%, quicklime 2 - 8%, water retaining agent 1 - 6%, plant ash 1 - 5%.

2. The biomass self-heating cultivation material according to claim 1, characterized in that, The biomass raw material is a mixture of at least one plant biomass such as Chinese herbal medicine residue, sawdust, plant straw, peanut shell, rice husk, cottonseed hull, wheat bran, soybean meal and dehydrated livestock and poultry manure.

3. The biomass self-heating cultivation material according to claim 2, characterized in that, The mass ratio of the plant biomass to the dehydrated livestock and poultry manure is 3 - 5:

1.

4. A biomass self-heating cultivation material according to claim 1, characterized in that, The water retaining agent is any one of polyacrylamide water retaining agent, acrylamide - acrylate copolymer water retaining agent, polyacrylate water retaining agent, acrylate - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer water retaining agent.

5. The self-heating cultivation material made of biomass according to claim 1, characterized in that, The water retaining agent is a polyacrylate water retaining agent or an acrylate - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer water retaining agent with a neutralization degree of 30 - 70%.

6. The self-heating cultivation material made of biomass according to claim 1, wherein The water retaining agent is an acrylate - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer water retaining agent with a 2 - acrylamide - 2 - methylpropanesulfonic acid monomer content of 30 - 70%, which is prepared by the following method: Adding acrylic acid into water and neutralizing it with an alkali to a neutralization degree of 90 - 100% to obtain an acrylate solution, then adding 2 - acrylamide - 2 - methylpropanesulfonic acid monomer and stirring to mix evenly. The addition amount of the 2 - acrylamide - 2 - methylpropanesulfonic acid monomer is 30 - 70% of the total molar amount of acrylic acid and 2 - acrylamide - 2 - methylpropanesulfonic acid. After deoxidizing with nitrogen, adding a redox initiator and a cross - linker to carry out a copolymerization reaction. After the reaction is completed, spray drying is carried out to obtain the acrylate - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer water retaining agent.

7. The biomass self-heating cultivation material according to claim 6, characterized in that, The alkali is ammonia water, potassium hydroxide solution or sodium hydroxide solution.

8. A biomass self-heating cultivation material according to claim 6, characterized in that, The redox initiator is a redox initiator composed of ammonium persulfate solution and sodium bisulfite solution; the cross - linker is N,N - methylenebisacrylamide, and the dosage of the cross - linker is 0.05% - 0.1% of the total molar amount of acrylic acid and 2 - acrylamide - 2 - methylpropanesulfonic acid; the temperature of the copolymerization reaction is controlled at 50 - 70°C and the time is controlled at 3 - 6 h.

9. A method for preparing a biomass self-heating cultivation material according to any one of claims 1 to 8, characterized in that, Including the following steps: (1) Mixing quicklime, water retaining agent and plant ash evenly to obtain a chemical slow - release heating material; (2) Adjusting the moisture content of the biomass raw material to 50 - 60% to obtain a biomass fermentation material; (3) Mixing the chemical slow - release heating material and the biomass fermentation material evenly to obtain a biomass self - heating cultivation material.

10. Use of a biomass self - heating cultivation material according to any one of claims 1 - 8 in edible mushroom cultivation.

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