Liquid soil conditioner for rapid decomposition and carbon sequestration of straws as well as preparation method and application of liquid soil conditioner
By using a liquid soil conditioner prepared from Bacillus subtilis and nano-biochar fermentation liquid, the problems of long decomposition time and poor stability of straw after returning it to the field have been solved, achieving rapid carbon sequestration of straw and improvement of soil structure, thereby increasing soil organic carbon content and plant growth.
Patent Information
- Application Number
- CN202511156092.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-18
- Publication Date
- 2025-11-21
AI Technical Summary
In existing technologies, the decomposition time of straw after returning it to the field is long, and the efficiency of decomposition into organic matter is low. This is especially unfavorable for planting subsequent crops in areas with high multiple cropping indices. Furthermore, the colonization effect of exogenous decomposing bacteria in the soil is not good, and the conversion of straw carbon into soil stable organic carbon is not effective.
A liquid soil conditioner composed of Bacillus Zn-B strain and nano-biochar fermentation broth was used. By preparing a nano-biochar-zinc mixture and mixing it with the bacterial solution, the rapid decomposition of straw and carbon fixation were promoted, thereby improving soil structure and stability.
It significantly improves the degradation rate of straw, increases the content of stable organic carbon in soil, promotes the formation of soil aggregates, and enhances plant growth, thus having significant economic, ecological, and social benefits.
Smart Images
Figure CN120987709A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of soil carbon sequestration and straw return to the field, and in particular to a liquid soil conditioner for rapid decomposition and carbon sequestration of straw, its preparation method and application. Background Technology
[0002] Straw contains essential nutrients for crop growth, such as carbon, nitrogen, phosphorus, and potassium, and its return to the field has become an important agronomic measure for the reuse of straw resources. However, after straw is returned to the soil, it takes a long time to decompose under natural conditions, and the efficiency of decomposition into organic matter is low, especially in the south where the multiple cropping index is high, which is not conducive to the planting of subsequent crops.
[0003] Currently, some technologies exist to promote the rapid decomposition and return of straw to the field, often using fungi, actinomycetes, yeasts, cellulase, and chemical fertilizers to prepare decomposition-promoting agents to accelerate straw decomposition. However, these decomposition agents or technologies rarely consider the stable colonization of exogenous decomposition bacteria in the soil, resulting in minimal decomposition-promoting effects. Furthermore, even if decomposition-promoting agents accelerate straw decomposition, their effect on converting straw carbon into stable organic carbon in the soil is poor.
[0004] Therefore, in response to the difficulties in returning straw to the field and the low efficiency of soil carbon sequestration in areas with high multiple cropping, developing products that promote the rapid decomposition and carbon sequestration of straw is an urgent technical challenge to be solved in this field. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a liquid soil conditioner for rapid decomposition and carbon fixation of straw, its preparation method and application.
[0006] This invention is implemented as follows:
[0007] First, this invention provides a liquid soil conditioner for rapid decomposition and carbon fixation of straw, which is fermented from bacterial solution and biochar fermentation broth. The bacterial strain in the bacterial solution is Bacillus sp. Bacillus Zn-B, which is deposited at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, on April 12, 2019, with accession number CGMCC No. 17563.
[0008] Furthermore, the biochar fermentation broth is composed of the following raw materials: biochar, carbon source, organic nitrogen source, inorganic nutrients, and distilled water.
[0009] Furthermore, the biochar is nano-biochar.
[0010] Furthermore, the inorganic nutrient includes zinc sulfate.
[0011] Preferably, the biochar fermentation broth is composed of the following raw materials in the following mass ratio: 1-5% biochar, 2-8% carbon source, 0.5-1.5% organic nitrogen source, 0.3-0.5% zinc sulfate, 0.1-0.5% other inorganic nutrients, and the balance being distilled water.
[0012] More specifically, the carbon source includes glucose.
[0013] More specifically, the other inorganic nutrients include sodium nitrate and potassium phosphate.
[0014] Secondly, the present invention also provides a method for preparing the liquid soil conditioner, which specifically includes the following steps:
[0015] (1) Bacillus sp. Bacillus Zn-B strain was incubated in LB liquid medium at 30°C for 150 rpm. -1 Incubate for 12-24 hours under the specified conditions, then at 12000 r·min -1 Centrifuge for 5 min to collect bacterial cells. Wash the bacterial cells three times with sterile water rinse solution and resuspend them in an equal volume of sterile water to prepare seed culture. The effective viable count in the seed culture is >10. 9 cfu / ml;
[0016] (2) Crop straw is pyrolyzed at a temperature of 450-500℃ for 1.5-2 hours to obtain straw biochar; then the straw biochar is ground to obtain nano-biochar.
[0017] (3) Mix 2% nano-biochar, 5% glucose, 1% amino acid powder, 0.3%-0.5% ZnSO4, 0.1% NaNO3, 0.1% K2HPO4 and the remainder distilled water according to the mass ratio, and sterilize under high pressure to prepare nano-biochar-zinc mixture;
[0018] (4) Mix the seed liquid with the nano-biochar-zinc mixture at a volume ratio of 1:10 and place it in a fermentation tank. Let it stand at room temperature and be sealed for 3-5 days to obtain a liquid soil conditioner.
[0019] Finally, the present invention provides the application of the liquid soil conditioner, wherein the liquid soil conditioner is sprayed evenly onto the soil surface at a rate of 10-20 kg / mu or diluted 5-10 times before spraying, wherein the soil contains crop straw.
[0020] The present invention has the following advantages: The liquid soil conditioner prepared by the present invention, when used in conjunction with straw return to the field, can promote the rapid decomposition of straw, improve soil structure and promote the formation of aggregates, increase soil stability, organic carbon content and promote plant growth, and has significant economic, ecological and social benefits. Attached Figure Description
[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0022] Figure 1 The variation of soil organic carbon content in different implementation cases (the determination of soil organic carbon content was carried out in accordance with the standard "HJ 615-2011 Determination of Soil Organic Carbon by Potassium Dichromate Oxidation-Spectrophotometry").
[0023] Figure 2 For different implementation cases, soil aggregates R 0.25 The changes in values (soil aggregates were graded using the wet sieving method, and the values were determined with reference to the literature "Wang Yixiang, Weng Boqi, Huang Yibin, et al. Effects of sod cultivation on soil aggregates and organic carbon distribution in orchards. Journal of Tropical and Subtropical Botany, 2012, 20(4):349-355.").
[0024] Figure 3 The changes in soil mineral-associated organic carbon content in different implementation cases were investigated (the soil mineral-associated organic carbon content was measured with reference to the literature "Zhu E, Liu Z, Ma L, et al. Enhanced mineral preservation rather than microbial residue production dictates the accrual of mineral-associated organic carbon along a weathering gradient. Geophysical Research Letters, 2024, 51, e2024GL108466"). Detailed Implementation
[0025] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings and specific embodiments. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0026] A method for preparing a liquid soil conditioner for rapid decomposition and carbon sequestration of straw, specifically including the following steps:
[0027] (1) Bacillus sp. Bacillus Zn-B strain was incubated in LB liquid medium at 30°C for 150 rpm. -1 Incubate for 12-24 hours under the specified conditions, then at 12000 r·min -1Centrifuge for 5 min to collect bacterial cells. Wash the bacterial cells three times with sterile water rinse solution and resuspend them in an equal volume of sterile water to prepare seed culture. The effective viable count in the seed culture is >10. 9 cfu / ml;
[0028] (2) Crop straws such as corn and rice are pyrolyzed at a temperature of 450-500℃ for 1.5-2 hours to obtain straw biochar. Then, the straw biochar is placed in a ball mill with a ball-to-powder ratio of 18:1, a rotation speed of 400 r / min, and a time of 2-3 hours to obtain nano-biochar (average particle diameter <100 nm).
[0029] (3) The nano-biochar-zinc mixture was prepared by mixing 2% nano-biochar, 5% glucose, 1% amino acid powder, 0.3%-0.5% ZnSO4, 0.1% NaNO3, 0.1% K2HPO4 and the remainder distilled water according to the mass ratio and sterilizing under high pressure.
[0030] (4) Mix the seed culture liquid with the nano-biochar-zinc mixture at a volume ratio of 1:10 and place it in a fermentation tank. Incubate at room temperature, stand still and in a sealed environment for 3-5 days to obtain a liquid soil conditioner.
[0031] Spray the above-mentioned liquid soil conditioner evenly onto the soil surface at a rate of 10-20 kg / mu, or dilute it 5-10 times before spraying, and then use a rotary tiller to perform rotary tillage and stubble removal operations.
[0032] Application Implementation Cases
[0033] Rice straw was chopped into pieces <3cm, and 10g of rice straw was weighed (denoted as MS). This was then placed into an 8cm x 8cm nylon mesh bag with an 80-mesh aperture. The bag was then buried in a 15cm diameter plastic pot filled with 2kg of air-dried soil at a depth of 5cm. Liquid soil conditioner was then evenly sprayed onto the soil surface, and finally, the soil moisture content was watered until it reached 70% of its field capacity. All pots were placed at 25℃ for 50 days of constant temperature incubation. After incubation, the nylon mesh bags were removed, and the straw residue was collected, rinsed clean, and placed in an oven to constant weight. The weight of the residual straw was measured (denoted as MD). The straw degradation rate was calculated according to the following formula, and the results are shown in Table 1.
[0034] Straw degradation rate (%) = (MS - MD) / MS × 100%;
[0035] MS represents the initial dry weight of straw (g); MD represents the dry weight of straw after decomposition (g).
[0036] The determination of the 50-day degradation rate of rice straw under different soil amendment applications (all other conditions being the same) showed that there was no significant difference in the 50-day degradation rate between the treatment without amendment (CK) and the treatment with only nano-biochar (NB). The degradation rate of rice straw increased by more than 15.6% with the addition of only Bacillus Zn-B bacterial solution (BA). The degradation rate of rice straw with nano-biochar-Bacillus Zn-B liquid soil amendment (JF) was more than 32.7% higher than the treatment without amendment, and 14.8% higher than the single bacterial solution treatment, indicating that liquid soil amendments prepared by fermentation with the addition of biochar and other additives are more effective.
[0037] The degradation rate of rice straw was increased by 10.8% under the application of nano-biochar-zinc sulfate-Bacillus Zn-B liquid soil conditioner (JFZ) compared with the JF treatment. This indicates that the addition of zinc sulfate adjuvant in the fermentation preparation of liquid conditioner enhances the metabolic activity of Bacillus Zn-B through the action of zinc and sulfur elements, thereby improving the degradation efficiency of rice straw.
[0038] Table 1. Straw degradation rate under different amendments
[0039]
[0040] A field experiment based on double-cropping rice was conducted, with three treatments: no liquid soil conditioner (CK), no zinc sulfate liquid soil conditioner (Case 1), and zinc sulfate liquid soil conditioner (Case 2) (ZnSO4 0.4% in Case 2, all other conditions were the same). Each treatment was replicated in three plots. After the early rice harvest, 20 kg / mu of liquid soil conditioner was manually sprayed onto the experimental plots according to the treatment, followed by rotary tillage to remove stubble. Late rice was planted in late August. Two years later, soil samples from the 0-20 cm soil layer were randomly collected from each plot to determine soil organic carbon, aggregate structure, and mineral-bound organic carbon (MAOC) content. The results are as follows: Figures 1-3 As shown.
[0041] In Case Study 1, the soil organic carbon content increased by 11.3% compared to the control, and in Case Study 2, it increased by 14.9% compared to the control. In Case Study 1, soil aggregates R... 0.25 The improvement was 7.0% compared to the control, and in Case 2, the improvement was 9.8% compared to the control.
[0042] Mineral-bound organic carbon (MAOC) is produced by microbial activity, with microbial carbon accounting for a relatively large proportion and playing a crucial role in soil organic carbon stability. It is also closely related to aggregate-bound carbon, forming an important mechanism for soil organic carbon sequestration. In Case Study 1, the soil mineral-bound organic carbon content increased by 17.8% compared to the control, and in Case Study 2, it increased by 25.4%. In Case Study 2, the addition of zinc sulfate enhanced Bacillus Zn-B metabolic activity and accelerated straw degradation. Both factors, through microbial activity and mineral surface chemistry, increased the accumulation and stability of mineral-bound organic carbon. For example, zinc ions promote the binding of organic carbon to mineral surfaces through bridging, thereby enhancing MAOC stability and consequently increasing the soil's stable organic carbon content and carbon sequestration efficiency.
[0043] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A liquid soil conditioner for rapid decomposition and carbon sequestration of straw, characterized in that: It was prepared by fermentation of bacterial culture and biochar fermentation broth. The bacterial strain in the bacterial culture is Bacillus sp. Bacillus Zn-B, which is deposited at the China General Microbiological Culture Collection Center, Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, on April 12, 2019, with accession number CGMCC No. 17563.
2. The liquid soil conditioner for rapid decomposition and carbon sequestration of straw according to claim 1, characterized in that: The biochar fermentation broth is composed of the following raw materials: biochar, carbon source, organic nitrogen source, inorganic nutrients, and distilled water.
3. A liquid soil conditioner for rapid decomposition and carbon sequestration of straw according to claim 2, characterized in that: The biochar is nano-biochar.
4. A liquid soil conditioner for rapid decomposition and carbon sequestration of straw according to claim 2, characterized in that: The inorganic nutrient includes zinc sulfate.
5. A liquid soil conditioner for rapid decomposition and carbon sequestration of straw according to claim 2, characterized in that: The biochar fermentation broth is composed of the following raw materials in the following mass ratio: 1-5% nano-biochar, 2-8% carbon source, 0.5-1.5% organic nitrogen source, 0.3-0.5% zinc sulfate, 0.1-0.5% other inorganic nutrients, and the balance being distilled water.
6. A liquid soil conditioner for rapid decomposition and carbon sequestration of straw according to claim 5, characterized in that: The carbon source includes glucose.
7. A liquid soil conditioner for rapid decomposition and carbon sequestration of straw according to claim 5, characterized in that: The other inorganic nutrients include sodium nitrate and potassium phosphate.
8. A method for preparing a liquid soil conditioner for rapid decomposition and carbon sequestration of straw, specifically comprising the following steps: (1) Bacillus sp. Bacillus Zn-B strain was incubated in LB liquid medium at 30°C for 150 rpm. -1 Incubate for 12-24 hours under the specified conditions, then at 12000 r·min -1 Centrifuge for 5 min to collect bacterial cells. Wash the bacterial cells three times with sterile water rinse solution and resuspend them in an equal volume of sterile water to prepare seed culture. The effective viable count in the seed culture is >10. 9 cfu / ml; (2) Crop straw is pyrolyzed at a temperature of 450-500℃ for 1.5-2 hours to obtain straw biochar; then the straw biochar is ground to obtain nano-biochar. (3) Mix 2% nano-biochar, 5% glucose, 1% amino acid powder, 0.3%-0.5% ZnSO4, 0.1% NaNO3, 0.1% K2HPO4 and the remainder distilled water according to the mass ratio, and sterilize under high pressure to prepare nano-biochar-zinc mixture; (4) The seed liquid and the nano-biochar-zinc mixture were mixed at a volume ratio of 1:10 and placed in a fermentation tank. The mixture was then allowed to stand at room temperature and cultured in a sealed environment to obtain a liquid soil conditioner.
9. The application of the liquid soil conditioner as described in claims 1-7 or the liquid soil conditioner prepared by the preparation method as described in claim 8 in soil, characterized in that: The liquid soil conditioner is sprayed evenly onto the soil surface at a rate of 10-20 kg / mu, or diluted 5-10 times before spraying, in soil containing crop straw.