Soil conditioner for improving soil hardening and preparation method thereof

Abstract

The invention provides a soil conditioner for improving soil hardening and a preparation method thereof, and relates to the technical field of soil conditioning. The soil conditioner is prepared by combining nano silicon dioxide, a straw retting material, a straw composite fermentation material, biochar, a water-retaining agent and modified starch. The straw composite fermented material is prepared by the following steps: crushing straws, mixing with sweet water, stirring, drying, carrying out microwave treatment, mixing with bacillus thuringiensis, fermenting, sterilizing, subsequently adding a composite microbial agent of bacillus subtilis, trichoderma and bacillus mucilaginosus, continuously fermenting, and drying. The modified starch is prepared by semi-gelatinizing corn starch and then carrying out microwave drying and shaping. According to the present invention, the defects in the prior art are overcome, the soil hardening phenomenon can be rapidly improved with the small addition amount, the soil porosity is increased, the activity and the diversity of the soil microorganisms are ensured, and the soil fertility is improved.

Description

Technical Field

[0001] This invention relates to the field of soil conditioning technology, specifically to a soil conditioner for improving soil compaction and its preparation method. Background Technology

[0002] Soil compaction refers to the phenomenon where the surface layer of soil becomes structurally damaged, porosity is reduced, and texture hardens due to various factors, thus losing its original looseness, permeability, and good tillage performance. The main cause of soil compaction is the reduction in the use of organic fertilizers and the increase in dependence on chemical fertilizers in current agricultural planting, which leads to the destruction of soil aggregate structure and the occurrence of compaction.

[0003] Soil compaction reduces microbial activity and diversity, affects plant root development and growth, hinders the absorption of nutrients, leads to nutrient deficiency symptoms in crops, reduces crop yields, and affects farmers' income. Therefore, it is necessary to develop corresponding solutions to address this phenomenon.

[0004] Currently, conventional methods for improving soil compaction mainly include deep tillage, mixing in sand and gravel, and applying additional bio-organic fertilizers. However, deep tillage damages the surface layer of soil, leading to soil erosion, and the entire process requires a large investment of manpower and machinery, resulting in high costs and limited applicability. Applying additional bio-organic fertilizers can improve soil compaction to some extent and increase soil fertility to promote crop growth, but in practice, the overall effect is slow, and the improvement effect on compacted soil is negligible when the amount of organic fertilizer applied is small. Furthermore, different crops require different organic fertilizer compositions and amounts, so simply applying organic fertilizers is not widely applicable. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a soil conditioner for improving soil compaction and its preparation method. This conditioner can rapidly improve soil compaction with a small amount of additive, while increasing soil porosity, ensuring the activity and diversity of soil microorganisms, and improving soil fertility.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A soil conditioner for improving soil compaction, comprising the following components by weight: 10-20 parts nano-silica, 30-40 parts composted straw, 20-30 parts straw compound fermentation material, 8-10 parts biochar, 1-2 parts water-retaining agent, and 4-6 parts modified starch; wherein the composted straw is prepared by crushing straw, mixing it with manure water, composting and fermenting, and then drying; the straw compound fermentation material is prepared by crushing straw, mixing it with sugar water, drying it, microwave-treating it, fermenting it with Bacillus thuringiensis, sterilizing it, adding a compound inoculant of Bacillus subtilis, Trichoderma, and Bacillus mucilaginosa, continuing fermentation, and then drying it; and the modified starch is prepared by semi-gelatinizing corn starch and then microwave-drying and shaping it.

[0007] Preferably, the particle size of the nano-silica is 3-80 nm.

[0008] Preferably, the preparation method of the straw compound fermentation material includes the following steps: S1-1. Crush the straw and pass it through a 20-mesh sieve. Then, prepare a 12%-15% sucrose aqueous solution and mix it with the straw in an equal proportion. After stirring thoroughly, air dry the mixture to obtain a ready-made mixture. S1-2. After spreading the mixture evenly, microwave it with 700-800W power for 30-40 seconds to obtain the pretreated mixture for later use. S1-3. Add the above pretreated mixture to twice the volume of water, stir evenly, inoculate with Bacillus thuringiensis, ferment for 2-3 days, then sterilize to obtain the first fermented material for later use. S1-4. Mix Bacillus subtilis, Trichoderma and Bacillus mucilaginosus in a mass ratio of 2-3:1-2:1 as a compound microbial agent and inoculate it into the first fermentation material. Ferment for 10-12 hours, then air dry and crush it through an 80-mesh sieve to obtain the straw compound fermentation material for later use.

[0009] Preferably, the inoculation amount of Bacillus thuringiensis in steps S1-3 is 0.1%-0.2% of the total mass of the pretreated mixture; and the inoculation amount of the compound microbial agent in steps S1-4 is 0.2%-0.3% of the total mass of the first fermentation material.

[0010] Preferably, the specific preparation method of the modified starch includes the following steps: S2-1. Add corn starch to 5-8 times the amount of deionized water and stir at 65±2℃ for 20-30 minutes to obtain semi-gelatinized starch slurry for later use. S2-2. After vacuum concentration of the above semi-gelatinized starch slurry, freeze-dry it and then microwave it for 1-3 minutes at 400-600W to obtain modified starch.

[0011] Preferably, the water-retaining agent is hydroxyethyl cellulose.

[0012] Preferably, the preparation method includes the following steps: (1) Mix the straw composite fermentation material with nano-silica thoroughly and evenly to obtain a mixture for later use; (2) Add 5 times the volume of water to the mixture and then add biochar. Stir at 1200-1400 r / min and then add modified starch and water-retaining agent. Adjust the speed to 180-400 r / min and continue stirring to obtain the stirred material for later use. (3) Dry the above-mentioned mixing material to a moisture content of 80%±5%, then mix it with straw compost, mix evenly and air dry to obtain soil conditioner.

[0013] In step (2), the biochar is ground through a 10-mesh sieve before use.

[0014] Preferably, the high-speed stirring time in step (2) is 10-15 min, and the stirring time is 20-30 min.

[0015] Preferably, the air-drying temperature in step (3) is 30-40℃.

[0016] This invention provides a soil conditioner for improving soil compaction and its preparation method, which has the following advantages compared with the prior art: This invention uses straw and nano-silica as the main raw materials. Nano-silica can improve the physical structure of soil to a certain extent, increase porosity, improve water holding capacity, and adsorb cations to prevent nutrient loss. Straw is widely available and inexpensive. Straw compost can be used as a raw material for organic fertilizer to supplement soil fertility. The straw compound fermentation material provides fertility while rapidly improving soil compaction through fermentation products and retained microorganisms combined with subsequent biochar and modified starch. This shortens the soil improvement time and improves the improvement effect. Moreover, by mixing multiple substances, better improvement effect can be achieved with less usage, thus saving the overall cost of soil improvement. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the Shannon index of microorganisms in the soil of the experimental group and the control group after 6 months of treatment in an embodiment of the present invention; Figure 2 This is a schematic diagram of the Chao1 index of microorganisms in the soil after 6 months of treatment in the experimental and control groups in this embodiment of the invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The Bacillus thuringiensis used in the following examples has the accession number CGMCC No. 13302. This strain has been disclosed in patent application number CN201710107284.8, and its viable count is 10. 9 Bacillus subtilis was purchased from Jinan Jinyuyuan Biotechnology Co., Ltd., and the viable count was 10⁶ cells / g. 10 The viable count of *Bacillus gelatinosa* is 10⁶ cells / g; its accession number is CGMCC NO. 4667. This strain has been disclosed in patent application CN201110124488.5. 9 The Trichoderma species is *Trichoderma harzianum*, with accession number GDMCC NO: 61869. This strain has been disclosed in patent application number CN202111047864.5, and the viable count is 10. 9 pcs / g; The particle size of the nano-silica is 3-80nm; the biochar is coconut shell biochar; and the water-retaining agent is hydroxyethyl cellulose. Example 1:

[0020] I. Raw material preparation: 1. Straw composting (1) Select corn stalks as raw materials, crush them and mix them with manure water at a mass ratio of 3:1 to obtain a mixture; (2) The mixture is piled into long stacks 1.5-2 meters wide and 1-1.5 meters high, and left to stand naturally. The stack is turned over every 5 days, and the moisture content is controlled at 40%-60%. The stacking process lasts for 90 days. After drying at 70℃, the stack is crushed to obtain straw compost.

[0021] 2. Preparation of straw compound fermentation material: 2.1 Preparation of FJ-1: (1) Crush the corn stalks and pass them through a 20-mesh sieve. Then, prepare a 14% sucrose aqueous solution and mix it with the stalks in equal proportions. After stirring thoroughly, air dry the mixture to obtain a ready-made mixture. (2) After spreading the mixture evenly, microwave it for 30 seconds at 800W power to obtain a pretreated mixture for later use; (3) Add the above pretreated mixture to 2 times the volume of water and stir evenly. Then inoculate 0.2% of the total mass of the pretreated mixture with Bacillus thuringiensis. Ferment for 2 days, and then place it in a high-pressure steam environment at 121℃ for 15 minutes for sterilization to obtain the first fermentation material for later use. (4) Mix Bacillus subtilis, Trichoderma and Bacillus mucilaginosus in a mass ratio of 3:2:1 to make a compound microbial agent. Inoculate the compound microbial agent into the first fermentation material at a mass of 0.2% of the total mass of the first fermentation material. Ferment for 11 hours, air dry, crush and pass through an 80-mesh sieve to obtain FJ-1 for later use.

[0022] 2.2 Preparation of FJ-2: (1) Crush the corn stalks and pass them through a 20-mesh sieve. Then, prepare a 14% sucrose aqueous solution and mix it with the stalks in equal proportions. After stirring thoroughly, air dry the mixture to obtain a ready-made mixture. (2) After spreading the mixture evenly, microwave it for 30 seconds at 800W power to obtain a pretreated mixture for later use; (3) Add the above pretreated mixture to 2 times the volume of water and stir evenly. Then inoculate with 0.2% of the total mass of the pretreated mixture with Bacillus thuringiensis and ferment for 2 days to obtain the first fermented material for later use. (4) Mix Bacillus subtilis, Trichoderma and Bacillus mucilaginosus in a mass ratio of 3:2:1 to make a compound microbial agent. Inoculate the compound microbial agent into the first fermentation material at a mass of 0.2% of the total mass of the first fermentation material. Ferment for 11 hours, air dry, crush and pass through an 80-mesh sieve to obtain FJ-2 for later use.

[0023] 2.3 Preparation of FJ-3: (1) Crush the corn stalks and pass them through a 20-mesh sieve. Then, prepare a 14% sucrose aqueous solution and mix it with the stalks in equal proportions. After stirring thoroughly, air dry the mixture to obtain a ready-made mixture. (2) Add the above mixture to 2 times the volume of water and stir evenly. Then inoculate with 0.2% of the total mass of the pretreated mixture with Bacillus thuringiensis. Ferment for 2 days, and then place in a high-pressure steam environment at 121℃ for 15 minutes for sterilization to obtain the first fermentation material for later use. (3) Mix Bacillus subtilis, Trichoderma and Bacillus mucilaginosus in a mass ratio of 3:2:1 to make a compound microbial agent. Inoculate the compound microbial agent into the first fermentation material at a mass of 0.2% of the total mass of the first fermentation material. Ferment for 11 hours, air dry, crush and pass through an 80-mesh sieve to obtain FJ-3 for later use.

[0024] 2.4 Preparation of FJ-4: (1) Crush the corn stalks and pass them through a 20-mesh sieve. Then, prepare a 14% sucrose aqueous solution and mix it with the stalks in equal proportions. After stirring thoroughly, air dry the mixture to obtain a ready-made mixture. (2) After spreading the mixture evenly, microwave it for 30 seconds at 800W power to obtain a pretreated mixture for later use; (3) Mix Bacillus subtilis, Trichoderma and Bacillus mucilaginosus in a mass ratio of 3:2:1 to prepare a compound microbial agent; (4) Add 2 times the volume of water to the pretreated mixture and stir evenly. Then inoculate with 0.2% of the total mass of the pretreated mixture with compound microbial agent, ferment for 11 hours, air dry, crush and pass through an 80-mesh sieve to obtain FJ-4 for later use.

[0025] 3. Preparation of modified starch: (1) Add corn starch to 6 times the amount of deionized water and stir at 65±2℃ for 25 minutes to obtain semi-gelatinized starch slurry for later use. (2) After vacuum concentration of the above semi-gelatinized starch slurry, freeze-dry it and then microwave it for 2 minutes at 500W to obtain modified starch.

[0026] II. Preparation methods of soil conditioners: The specific preparation method is as follows: (1) Prepare materials according to the following mass ratio: 15 parts nano silica, 35 parts straw compost, 25 parts straw compound fermentation material, 9 parts biochar, 1.5 parts water retention agent, and 5 parts starch material; (2) Mix the straw composite fermentation material with nano-silica thoroughly and evenly to obtain a mixture for later use; (3) Add 5 times the volume of water to the mixture and then add biochar (ground through a 10-mesh sieve). Stir at 1200 r / min for 15 min and then add starch and water-retaining agent. Adjust the speed to 300 r / min and continue stirring for 25 min to obtain the stirred material for later use. (4) Dry the above-mentioned mixing material to a moisture content of 80%±5%, then mix it with straw compost, mix it evenly, and then air dry it at 35℃ to obtain soil conditioner.

[0027] Using the above preparation method, different soil conditioners were prepared by selecting different straw compound fermentation materials and starch materials according to Table 1 below: Table 1

[0028] Soil conditioner 6 does not contain straw compound fermented material, and straw compost is used to replace straw compound fermented material, referring to the ratio of soil conditioner 1. Detection:

[0029] Compacted farmland from the same corn-growing region in Qujing City, Yunnan Province, was selected as experimental material. This farmland was divided into 27 zones, each with an area of ​​10 square meters. 2Each zone was spaced 1.2m apart, with three zones forming a group. Different soil conditioners were applied to each group, followed by tilling. Soil properties were tested regularly to assess the relief of compaction. The specific application of soil conditioners is shown in Table 2 below. Table 2

[0030] 1. Soil samples were taken from each group at 30 and 90 days after treatment to test the soil properties (soil samples were taken from each area of ​​each group for testing, and the average value was taken). The sampled soil was air-dried and sieved for testing. The specific results are shown in Tables 3 and 4 below: Table 3. Soil performance test results after 30 days of treatment.

[0031] Table 4. Performance test results of soils in each group after 90 days of treatment.

[0032] As shown in the table above, both experimental groups 1-5 and experimental group 8 effectively reduced soil bulk density and increased soil porosity after 30 days, with experimental group 1 showing the best effect. Although experimental group 8 showed the highest increase in available potassium, the highest application rate in experimental group 8 made experimental groups 1-5 relatively more economical. Overall, the comparison shows that experimental group 1 was more efficient and effective in alleviating soil compaction, and its overall application cost was also lower.

[0033] 2. Following the above testing procedures, soil samples from the control group, experimental groups 1-5, and experimental group 8, after 6 months of treatment, were randomly numbered and their numbers recorded. These samples were then sent to the laboratory for soil microbial community diversity testing. The Chao1 index and Shannon index of the soil microbial community were calculated and statistically analyzed. Specific results are shown in [link to results]. Figure 1 and Figure 2 In the figure, CF-1 is experimental group 2, CF-2 is experimental group 1, CF-3 is experimental group 4, CF-4 is control group, CF-5 is experimental group-8, and CF-6 is experimental group 3. It can be seen that experimental group 1 has a higher microbial diversity index.

[0034] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A soil conditioner for improving soil compaction, characterized in that, The soil conditioner is composed of the following components by weight: 10-20 parts nano-silica, 30-40 parts straw compost, 20-30 parts straw compound fermentation material, 8-10 parts biochar, 1-2 parts water-retaining agent, and 4-6 parts modified starch. The straw compost material is prepared by crushing straw, mixing it with manure water, composting and fermenting it, and then drying it. The straw compound fermentation material is obtained by crushing straw, mixing it with sugar water, drying it, microwave treatment, mixing it with Bacillus thuringiensis for fermentation, sterilizing it, adding a compound inoculant of Bacillus subtilis, Trichoderma and Bacillus mucilaginosa for further fermentation, and then drying it. The modified starch was prepared by microwave drying and shaping of semi-gelatinized corn starch.

2. The soil conditioner according to claim 1, characterized in that: The particle size of the nano-silica is 3-80 nm.

3. The soil conditioner according to claim 1, characterized in that, The preparation method of the straw compound fermentation material includes the following steps: S1-1. Crush the straw and pass it through a 20-mesh sieve. Then, prepare a 12%-15% sucrose aqueous solution and mix it with the straw in an equal proportion. After stirring thoroughly, air dry the mixture to obtain a ready-made mixture. S1-2. After spreading the mixture evenly, microwave it with 700-800W power for 30-40 seconds to obtain a pretreated mixture for later use. S1-3. Add the above pretreated mixture to twice the volume of water, stir evenly, inoculate with Bacillus thuringiensis, ferment for 2-3 days, then sterilize to obtain the first fermented material for later use. S1-4. Mix Bacillus subtilis, Trichoderma and Bacillus mucilaginosus in a mass ratio of 2-3:1-2:1 as a compound microbial agent and inoculate it into the first fermentation material. Ferment for 10-12 hours, then air dry and crush it through an 80-mesh sieve to obtain the straw compound fermentation material for later use.

4. The soil conditioner according to claim 3, characterized in that: In steps S1-3, the inoculation amount of Bacillus thuringiensis is 0.1%-0.2% of the total mass of the pretreated mixture; in steps S1-4, the inoculation amount of the compound microbial agent is 0.2%-0.3% of the total mass of the first fermentation material.

5. The soil conditioner according to claim 1, characterized in that, The specific preparation method of the modified starch includes the following steps: S2-1. Add corn starch to 5-8 times the amount of deionized water and stir at 65±2℃ for 20-30 minutes to obtain semi-gelatinized starch slurry for later use. S2-2. After vacuum concentration of the above semi-gelatinized starch slurry, freeze-dry it and then microwave it for 1-3 minutes at 400-600W to obtain modified starch.

6. The soil conditioner according to claim 1, characterized in that: The water-retaining agent is hydroxyethyl cellulose.

7. A method for preparing a soil conditioner as described in any one of claims 1-6, characterized in that, The preparation method includes the following steps: (1) Mix the straw composite fermentation material with nano-silica thoroughly and evenly to obtain a mixture for later use; (2) Add 5 times the volume of water to the mixture and then add biochar. Stir at 1200-1400 r / min and then add modified starch and water-retaining agent. Adjust the speed to 180-400 r / min and continue stirring to obtain the stirred material for later use. (3) Dry the above-mentioned mixing material to a moisture content of 80%±5%, then mix it with straw compost, mix evenly and air dry to obtain soil conditioner.

8. The preparation method according to claim 7, characterized in that: In step (2), the biochar is ground through a 10-mesh sieve before use.

9. The preparation method according to claim 7, characterized in that: In step (2), the high-speed stirring time is 10-15 minutes, and the stirring time is 20-30 minutes.

10. The preparation method according to claim 7, characterized in that: The air-drying temperature in step (3) is 30-40℃.

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