Composite soil conditioner for promoting conversion of straw carbon into soil organic carbon and preparation method and application thereof

Abstract

The invention discloses a composite soil conditioner for promoting conversion of straw carbon into soil organic carbon and a preparation method and application thereof. The composite soil conditioner is prepared from the following components in percentage by weight: 5 to 20 percent of microbial powder, 50 to 80 percent of manganese fertilizer and 5 to 45 percent of water. The number of effective viable bacteria in the microbial powder is 10-15 billion / g; the manganese fertilizer is powdery, and the effective content is greater than or equal to 99%. According to the invention, the microbial powder and the manganese fertilizer are combined and applied, so that a greater effect can be exerted through interaction, straw decomposition and soil organic carbon turnover are synchronously accelerated, the soil fertility is further improved, and crop growth is promoted. The preparation and application method is simple to operate, low in cost and capable of being popularized and copied in a large scale.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement, and in particular to a composite soil improver for promoting the conversion of straw carbon into soil organic carbon, and a preparation method and application thereof. Background Art

[0002] As a major agricultural country, China possesses abundant straw resources. Since the 1950s, my country has actively promoted the comprehensive utilization of straw. Returning straw to the fields, as a simple and economical way to utilize straw resources, offers excellent ecological and economic benefits and has been widely adopted in recent years. However, farmland in the middle and lower reaches of the Yangtze River in my country often utilizes a two- or even three-crop system. Under this compact system, straw cannot be fully decomposed after being returned to the fields, hindering land preparation and seedling planting in the next round, fostering the growth of pathogens and pest eggs, and ultimately affecting the yield and quality of the next crop. Therefore, appropriate measures are needed to accelerate straw decomposition and promote soil organic carbon turnover.

[0003] Currently, common soil conditioners are primarily biological agents made from single or multiple microorganisms. However, these agents suffer from limitations such as limited functional strains, poor environmental adaptability, limited decomposition efficiency, and the risk of introducing pests and diseases. Therefore, developing a composite soil conditioner with broad environmental applicability that promotes the conversion of straw carbon into soil carbon is a pressing technical challenge. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art by providing a composite soil conditioner that promotes the conversion of straw carbon to soil organic carbon, as well as its preparation method and application. The composite soil conditioner of the present invention can accelerate straw decomposition and soil organic carbon turnover, thereby improving soil fertility and promoting crop growth.

[0005] To achieve the above purpose, the technical solution designed by the present invention is as follows:

[0006] The invention provides a composite soil conditioner for promoting the conversion of straw carbon into soil organic carbon. The composite soil conditioner consists of 5% to 20% of microbial powder, 50% to 80% of manganese fertilizer and 5% to 45% of water by weight.

[0007] Furthermore, the composite soil conditioner is composed of 5% to 15% of microbial powder, 60% to 75% of manganese fertilizer and 10% to 35% of water in percentage by weight.

[0008] Furthermore, the effective viable bacteria count in the microbial powder is 1 to 1.5 billion / g, and the manganese fertilizer is in powder form with an effective content of ≥99%.

[0009] Furthermore, the microbial powder is Trichoderma harzianum powder, and the manganese fertilizer is any one of manganese sulfate, manganese chloride and manganese nitrate.

[0010] Furthermore, the composite soil conditioner consists of 75% manganese sulfate, 10% water and 15% Trichoderma harzianum powder by weight.

[0011] The present invention also provides a method for preparing the composite soil conditioner, comprising the following steps:

[0012] (1) Weigh manganese fertilizer, water and microbial powder according to the above weight percentages;

[0013] (2) The weighed manganese fertilizer, water and microbial powder are mixed to obtain a composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon.

[0014] The present invention also provides an application of the composite soil conditioner in promoting the conversion of straw carbon into soil organic carbon, characterized in that the composite soil conditioner is added to the soil and straw is added, and after culturing for 70 to 80 days, the conversion of straw carbon into soil organic carbon can be promoted.

[0015] Furthermore, the mass ratio of the composite soil conditioner, straw and soil is 1:4-6:400-600.

[0016] Furthermore, the mass ratio of the composite soil conditioner, straw and soil is 1:5:500.

[0017] Furthermore, the basic physical and chemical properties of the soil are: pH = 6.10, C (%) = 1.32, N (%) = 0.23, organic matter 14.93 g / kg; the straw carbon is cellulose and lignin, and the soil organic carbon is aromatic compounds and lipid compounds.

[0018] Beneficial effects of the present invention:

[0019] The composite soil conditioner of the present invention is composed of carefully selected raw materials, with optimized content of each raw material, and an appropriately proportioned microbial powder and manganese fertilizer. These materials leverage the advantages of each, complementing and promoting each other. The resulting composite soil conditioner has the advantage of promoting the conversion of straw carbon into soil organic carbon.

[0020] First, manganese is an important biooxidizing metal element and a common active component in soil. It is sensitive to redox reactions and can interact with organic compounds, influencing ecosystem carbon dynamics by mediating multiple biochemical pathways. Furthermore, manganese is essential for the production of manganese peroxidase, which oxidizes unreacted Mn(II) in plant residues and soil into active Mn(III). This Mn(III), stabilized by organic ligands, can oxidize and degrade aromatic structures in lignin. Trichoderma harzianum is one of the earliest and most widely used Trichoderma species and possesses important biocontrol value.

[0021] Secondly, compared with applying microbial powder or manganese fertilizer separately, applying the two components together can accelerate the decomposition of returned straw to a greater extent, promote the turnover of soil organic carbon, and promote the absorption of macro- and micronutrients by farmland plants, thereby improving the bioavailability of insoluble or sparingly soluble elements.

[0022] In summary, the combined application of microbial powder and manganese fertilizer can enhance their synergistic effects, simultaneously accelerating straw decomposition and soil organic carbon turnover, thereby improving soil fertility and promoting crop growth. Furthermore, the preparation and application methods of the present invention are simple to operate, cost-effective, and can be widely promoted and replicated. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below with reference to specific embodiments so that those skilled in the art can understand.

[0024] Experimental material requirements

[0025] 1. The effective number of live bacteria in microbial powder is 1-1.5 billion / g;

[0026] 2. Manganese fertilizer is in powder form with an effective content of ≥99%.

[0027] Example 1

[0028] A composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon

[0029] The composite soil conditioner of this embodiment is composed of 60% manganese fertilizer, 35% water and 5% microbial powder by weight, wherein the microbial powder is Trichoderma harzianum powder produced by a Hubei Bioengineering Co., Ltd., and the manganese fertilizer is manganese sulfate. The preparation method thereof comprises the following steps:

[0030] 1. At room temperature, weigh manganese sulfate, water, and Trichoderma harzianum powder in percentage by weight;

[0031] 2. Evenly mix the weighed raw materials to obtain a composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon.

[0032] Example 2

[0033] A composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon

[0034] The composite soil conditioner of this embodiment is composed of 75% manganese fertilizer, 20% water and 5% microbial powder by weight, wherein the microbial powder is Trichoderma harzianum powder produced by a Hubei Bioengineering Co., Ltd., and the manganese fertilizer is manganese sulfate. The preparation method thereof comprises the following steps:

[0035] 1. At room temperature, weigh manganese sulfate, water, and Trichoderma harzianum powder in percentage by weight;

[0036] 2. Evenly mix the weighed raw materials to obtain a composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon.

[0037] Example 3

[0038] A composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon

[0039] The composite soil conditioner of this embodiment is composed of 60% manganese fertilizer, 25% water and 15% microbial powder by weight, wherein the microbial powder is Trichoderma harzianum powder produced by a Hubei Bioengineering Co., Ltd., and the manganese fertilizer is manganese sulfate. The preparation method thereof comprises the following steps:

[0040] 1. At room temperature, weigh manganese sulfate, water, and Trichoderma harzianum powder in percentage by weight;

[0041] 2. Evenly mix the weighed raw materials to obtain a composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon.

[0042] Example 4

[0043] A composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon

[0044] The composite soil conditioner of this embodiment is composed of 75% manganese fertilizer, 10% water and 15% microbial powder by weight, wherein the microbial powder is Trichoderma harzianum powder produced by a Hubei Bioengineering Co., Ltd., and the manganese fertilizer is manganese sulfate. The preparation method thereof comprises the following steps:

[0045] 1. At room temperature, weigh manganese sulfate, water, and Trichoderma harzianum powder in percentage by weight;

[0046] 2. Evenly mix the weighed raw materials to obtain a composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon.

[0047] Example 5

[0048] A composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon

[0049] The composite soil conditioner of this embodiment is the same as that of Example 1, except that the manganese fertilizer is manganese chloride.

[0050] Example 5

[0051] A composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon

[0052] The composite soil conditioner of this embodiment is the same as that of Example 1, except that the manganese fertilizer is manganese nitrate.

[0053] Example 6

[0054] Application of composite soil conditioner to promote the conversion of straw carbon to soil organic carbon

[0055] The composite soil conditioners of Examples 1 to 4 were used to promote the conversion of straw carbon into soil organic carbon.

[0056] The test soil was the 0-20 cm deep plough layer soil in a rice field in Hubei Province. The basic physical and chemical properties of the soil were as follows: pH = 6.10, C (%) = 1.32, N (%) = 0.23, and organic matter 14.93 g / kg.

[0057] The straw used for the test was 13 C-labeled rice straw. The basic physical and chemical properties of the straw are: C (%) = 36.49, indicating that every 100 g of dry rice straw contains 36.49 g of C; N (%) = 2.30, indicating that every 100 g of dry rice straw contains 2.30 g of N; 13 The atomic percentage of C is 3.10%, and the harvest stage is the rice maturity stage. 13 C marked rice straw was air-dried and chopped into 1 cm segments.

[0058] 1. Each bottle contained 80 g of soil and 0.8 g of straw. 0.16 g of the composite soil conditioner of Examples 1 to 4 was added to the soil and straw mixture, respectively. Three replicates were set up and cultured in a constant temperature incubator at 25° C. for 80 days. Changes in soil microbial biomass carbon, dissolved organic carbon, mineral-bound organic carbon, particulate organic carbon, soil dissolved organic carbon ultraviolet spectral parameters, and soil dissolved organic carbon fluorescence components were measured. A blank control group was also used, in which no conditioner was added.

[0059] 2. Table 1 shows the effects of composite soil conditioners on straw carbon ( 13 C) Effect of distribution in different organic carbon components. Compared with the blank group, the 13 C-microbial biomass carbon and 13 The dissolved organic carbon content of C- 13 C-mineral bound organic carbon and 13 The content of C-particulate organic carbon increased significantly. 13 C-microbial biomass carbon content was the highest, and with the application of the modifier (Example 1 to Example 4), its content gradually decreased, with Example 4 reaching the lowest (15.06 mg / kg). 13C-soluble organic carbon was the highest in the blank group, but significantly decreased in the amendment-treated group, especially in Example 4 (10.29 mg / kg). This indicates that the amendment inhibited the short-term utilization of straw carbon by microorganisms or promoted the transformation of carbon to a more stable form. At the same time, the amendment treatment significantly increased the proportion of straw carbon in mineral-bound and particulate organic carbon. 13 The content of C-mineral-bound organic carbon was the lowest, while that of Example 4 was the highest (0.76 g / kg). 13 The C-particulate organic carbon content also increased from 0.5 g / kg in the blank group to 0.73 g / kg in Example 4. These results indicate that the composite soil amendment improves the stability of soil organic carbon by promoting the binding of straw carbon to mineral particles or enhancing their physical protection. Therefore, the composite soil amendment optimizes the distribution of straw carbon, reduces its short-term decomposition loss, and enhances its long-term sequestration capacity in the soil, playing a positive role in improving the stability of the soil carbon pool.

[0060] Table 1 Effect of composite soil conditioners on straw carbon ( 13 C) Impact of distribution

[0061]

[0062]

[0063] 3. SUVA 254 Characterizes the degree of humification of soil dissolved organic carbon (DOC). The larger the value, the stronger the aromaticity of DOC. 260 Characterizes the content of DOC hydrophobic components. The larger the value, the more DOC hydrophobic components. E2 / E3 is used to estimate the relative size of DOC molecular weight. Table 2 shows that the composite soil amendment significantly changed the DOC spectral characteristics. 254 and SUVA 260 The value was highest in the blank group, while it decreased significantly in the amendment-treated groups (Examples 1 to 4), with Example 4 being the lowest. In contrast, the E2 / E3 ratio was lowest in the blank group and increased significantly with amendment treatment, reaching a maximum in Example 4. Therefore, the composite soil amendment optimized the organic carbon conversion process by reducing the aromaticity of DOC and increasing its hydrophilicity, thereby affecting its migration and stability in the soil.

[0064] Table 2 Effects of composite soil conditioners on UV spectral parameters of soil dissolved organic carbon

[0065] <![CDATA[SUVA 254 ]]> <![CDATA[SUVA 260 ]]> E2 / E3 Blank group 5.59±0.43a 5.48±0.97a 2.07±0.26c Example 1 2.38±0.21bc 2.66±0.20b 2.63±0.25c Example 2 2.57±0.04bc 2.34±0.24b 2.79±0.19c Example 3 2.15±0.06c 2.10±0.07b 3.87±0.54b Example 4 1.94±0.06d 1.91±0.06b 5.04±0.13a

[0066] 4. The data in Table 3 show that the composite soil amendment significantly changed the composition of fluorescent components of DOC. Compared with the blank group, the amendment treatment significantly increased the proportion of fulvic acid-like components (from 32.34% to 40.08%) and protein-like components (from 19.20% to 31.41%), while the proportion of humus-like components decreased from 47.77% to 26.85%. These changes indicate that the composite soil amendment promoted the conversion of humus to more active fulvic acid and protein components, enhancing the biological activity of DOC, while the reduction of humus-like components reduced the persistence of DOC. This result is consistent with the trend of changes in DOC molecular characteristics in Table 2, indicating that the amendment optimized the conversion process of organic carbon.

[0067] Table 3 Effects of composite soil conditioners on changes in soil dissolved organic carbon fluorescence components

[0068] Fulvic acid (%) Humus-like substances (%) Protein-like protein (%) Blank group 32.34±1.61b 19.20±1.01b 47.77±2.54a Example 1 36.99±1.34a 20.89±1.72b 39.06±2.52b Example 2 37.02±2.22a 22.84±1.30b 36.55±3.52b Example 3 39.67±0.89a 24.78±0.98b 31.08±1.23bc Example 4 40.08±0.15a 31.41±1.87a 26.85±1.99d

[0069] Note: Different letters indicate significant differences among different treatments, P < 0.05.

[0070] 5. The data in Table 4 show that the composite soil amendment significantly affects the chemical composition of straw organic carbon. The functional group composition of straw organic carbon changed significantly with the adjustment of the amendment concentration. The cellulose content decreased from 15.6% to 3.6%, the lignin content decreased from 10.8% to 6.2%, and the polysaccharide carbon content decreased significantly from 41.1% to 14.7%. At the same time, the aliphatic carbon content increased significantly (from 25.4% to 56.9%), and the aromatic carbon content also increased (from 10.3% to 13.9%). Therefore, the composite soil amendment not only accelerated the conversion of easily decomposable components in straw but also promoted the accumulation of aliphatic compounds and increased the degree of aromatization in straw organic carbon. From the perspective of soil carbon cycling, this change in functional group composition means that the chemical stability of organic carbon is enhanced, because aliphatic and aromatic compounds are generally more resistant to decomposition than polysaccharides and cellulose.

[0071] Table 4 Effects of composite soil conditioners on the functional group composition of straw organic carbon

[0072]

[0073] Although the above embodiments have been described in detail, they are only a part of the embodiments of the present invention, not all of them. People can also obtain other embodiments based on this embodiment without inventiveness, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A composite soil conditioner for promoting the conversion of straw carbon into soil organic carbon, characterized by: Calculated by weight percentage, the composite soil improver consists of 5% to 20% of microbial powder, 50% to 80% of manganese fertilizer and 5% to 45% of water.

2. The composite soil conditioner according to claim 1, characterized in that: Calculated by weight percentage, the composite soil improver consists of 5% to 15% of microbial powder, 60% to 75% of manganese fertilizer and 10% to 35% of water.

3. The composite soil conditioner according to claim 2, characterized in that: The effective live bacteria count in the microbial powder is 1 to 1.5 billion / g; the manganese fertilizer is in powder form, and the effective content is ≥99%.

4. The composite soil conditioner according to claim 3, characterized in that: The microbial powder is Trichoderma harzianum powder, and the manganese fertilizer is any one of manganese sulfate, manganese chloride and manganese nitrate.

5. The composite soil conditioner according to claim 4, characterized in that: Calculated by weight percentage, the composite soil conditioner consists of 75% manganese sulfate, 10% water and 15% Trichoderma harzianum powder.

6. A method for preparing the composite soil conditioner according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Weigh manganese fertilizer, water and microbial powder according to the above weight percentages; (2) The weighed manganese fertilizer, water and microbial powder are mixed to obtain a composite soil conditioner that promotes the conversion of straw carbon into soil organic carbon.

7. Use of the composite soil conditioner according to any one of claims 1 to 5 in promoting the conversion of straw carbon into soil organic carbon, characterized in that: The composite soil conditioner is added to the soil and straw is added, and after culturing for 70 to 80 days, the conversion of straw carbon into soil organic carbon can be promoted.

8. The use according to claim 7, characterized in that: The mass ratio of the composite soil improver, straw and soil is 1:4-6:400-600.

9. The use according to claim 8, characterized in that: The mass ratio of the composite soil improver, straw and soil is 1:5:

500.

10. The use according to claim 7, characterized in that: The basic physical and chemical properties of the soil are: pH = 6.10, C = 1.32%, N = 0.23%, organic matter 14.93 g / kg; The straw carbon is cellulose and lignin, and the soil organic carbon is aromatic compounds and lipid compounds.

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