A desertification soil improvement agent and a preparation method thereof

Abstract

The application belongs to the technical field of soil improvement, and relates to a sandy soil improver and a preparation method thereof.A soil temperature adjusting particle is prepared first, the particle is prepared by loading a phase change material on bentonite and then coating the particle with degradable resin, the particle can adjust the temperature of sandy soil, can reduce the soil temperature during the day, can improve the soil temperature at night, and can avoid the problem that the temperature difference between day and night of sandy soil is too large.Further, the sandy soil improver is prepared for improving sandy soil, a straw charcoal adsorbs a microbial agent, conditions for growth and metabolism of microorganisms are provided by humic acid and the like, the structure of sandy soil can be improved, the soil aggregation capacity can be improved, meanwhile, the metabolism of microorganisms, the straw charcoal, the humic acid and the composite polymer can all increase the organic matter content of soil, the soil fertility can be improved, and the water retention capacity and the air permeability can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of soil improvement, and more particularly to a sandy soil improver and a preparation method thereof. BACKGROUND

[0002] Sandy soil is a kind of land with poor fertility, drought, instability and low productivity. Due to its poor water retention capacity, insufficient nutrients, poor stability, large temperature fluctuation, low biological activity and lack of granular structure, the growth of plants planted thereon is limited. At present, although there are some soil improvers, they often cannot solve the above problems at the same time. Therefore, it is necessary to develop a sandy soil improver that can comprehensively solve these problems. SUMMARY

[0003] The purpose of the present application is to provide a sandy soil improver and a preparation method thereof to solve the problems existing in the prior art.

[0004] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0005] One of the technical solutions of the present application: a soil temperature regulating particle is provided, which is a shell-core structure particle with bentonite as a carrier, dodecahydrate disodium hydrogen phosphate as a load, and degradable resin as a coating material.

[0006] Further, the degradable resin includes one of poly-3-hydroxyalkanoate (PHA), poly-beta-hydroxybutyrate (PHB), polylactic acid (PLA) and poly-epsilon-caprolactone (PCL).

[0007] Preferably, the molecular weight of the polylactic acid is 10,000-200,000; the molecular weight of the poly-epsilon-caprolactone is 10,000-100,000; the molecular weight of the poly-3-hydroxyalkanoate is 1,000-100,000; and the molecular weight of the poly-beta-hydroxybutyrate is 50,000-100,000.

[0008] The coating material in the present application is not limited to the four types described in the present application, but can also be a material that can form a degradable film that is insoluble in water and soluble in organic solvents, but since it is applied to soil improvement, the degradable material should not pollute the soil.

[0009] Further, the particle size of the bentonite is 5-10 mm, the porosity is 40-60%, the pore volume is 0.4-0.6 cm 3 / g, and the cation exchange capacity is 50-150 meq / 100g.

[0010] The limitation of porosity, pore volume and cation exchange capacity can enable good loading of dodecahydrate disodium hydrogen phosphate and guarantee the phase change performance of dodecahydrate disodium hydrogen phosphate.

[0011] The granules prepared by loading the phase change material on bentonite and then coating with the degradable resin can adjust the temperature of the desertification soil, can reduce the soil temperature during the day, can improve the soil temperature at night, can avoid the problem of large temperature difference between day and night of the desertification soil, and can provide a suitable growth and metabolism temperature range for microorganisms, and further improve the microorganism population structure of the desertification soil.

[0012] The second technical scheme of the present application provides a preparation method of the soil temperature adjusting granules, and the steps include:

[0013] The di-sodium hydrogen phosphate dodecahydrate is dissolved in water to obtain a di-sodium hydrogen phosphate dodecahydrate aqueous solution, and then bentonite particles are added, and after slow stirring for 30-60 min, solid-liquid separation is performed to obtain a solid product;

[0014] The solid product is air-dried at room temperature to obtain bentonite loaded with di-sodium hydrogen phosphate dodecahydrate;

[0015] The degradable resin is dissolved in chloroform at room temperature to prepare a saturated solution of the degradable resin, and then the bentonite loaded with di-sodium hydrogen phosphate dodecahydrate is added to the saturated solution, and stirred uniformly, and then the chloroform is removed to obtain the soil temperature adjusting granules.

[0016] Further, the mass ratio of the di-sodium hydrogen phosphate dodecahydrate to water is 1:1.

[0017] Further, the addition amount of the bentonite is not more than the liquid level of the di-sodium hydrogen phosphate dodecahydrate aqueous solution.

[0018] Further, the addition amount of the bentonite loaded with di-sodium hydrogen phosphate dodecahydrate is not more than the liquid level of the saturated solution.

[0019] The degradable resin can form a dense film on the surface of the bentonite particles, thereby protecting the di-sodium hydrogen phosphate dodecahydrate from phase separation during phase change, and providing nutrients for crops after the degradation of the dense film.

[0020] The third technical scheme of the present application provides an application of the above-mentioned soil temperature adjusting granules in a desertification soil improver.

[0021] The fourth technical scheme of the present application provides a desertification soil improver, and the raw materials include, by mass fraction:

[0022] The above-mentioned soil temperature adjusting granules 50-100 parts, straw charcoal 100-120 parts, fly ash 40-60 parts, humic acid 20-40 parts, composite polymer 20-30 parts, and composite microbial agent 2-5 parts.

[0023] Further, the composite polymer is composed of polyethyleneimine and polyvinylamine, and the mass ratio is 1:1.

[0024] Preferably, the molecular weight of the polyethyleneimine is 20000-25000; and the molecular weight of the polyvinylamine is 10000-15000.

[0025] The polyethyleneimine in the composite polymer has good water solubility and biological activity, can be degraded by microorganisms, and releases organic matter and nutrients, providing energy and nutrients for the growth and metabolism of microorganisms. Meanwhile, the polyethyleneimine can be combined with soil particles to form a stable complex, increasing the soil aggregation and water retention capacity, and improving the soil structure and fertility. The polyvinylamine can be combined with soil particles to form a stable complex, increasing the soil organic matter content, improving the soil aggregation and water retention capacity, and promoting the absorption and utilization of water and nutrients by plants, and improving the stress resistance and adaptability of plants.

[0026] Further, the composite microbial agent is composed of Azotobacter chroococcum, Bacillus mycoides, Bacillus megaterium and arbuscular mycorrhizal fungi, and the mass ratio is equal.

[0027] The strains with the functions of phosphorus and potassium solubilization and nitrogen fixation can provide nutrients for the growth and metabolism of crops, and also improve the microecological structure of the desertified soil. The arbuscular mycorrhizal fungi can form a symbiotic relationship with the plant roots, helping the plants to absorb water and nutrients, and promoting the growth and development of the plants.

[0028] Further, the straw carbon is corn straw carbon, the particle size is 10-20mm, and the aspect ratio is 3-4.

[0029] The fifth technical scheme of the present application provides a preparation method of the desertified soil improver, and the steps include:

[0030] The composite microbial agent, humic acid and straw carbon are mixed and stirred uniformly, and then are placed for 2-3h. Then, the fly ash, composite polymer and soil temperature adjusting particles are added and mixed uniformly to obtain the desertified soil improver.

[0031] The sixth technical scheme of the present application provides an application of the desertified soil improver in the repair and improvement of the desertified soil.

[0032] Further, the application method is that the desertified soil improver is uniformly scattered on the surface of the desertified soil, and then is subjected to rotary tillage treatment. After the rotary tillage treatment, the land is leveled, and the conventional crop planting can be performed after 10-15 days.

[0033] Preferably, the depth of the rotary tillage is 25-30cm.

[0034] Preferably, the application amount of the desertified soil improver is 600-1200kg / acre.

[0035] The deeper the sandification soil layer, the smaller the temperature change, therefore, the soil temperature regulation particle acts on the soil surface layer by rotary tillage treatment of 25-30cm, and the purpose of standing for 10-15 days after rotary tillage treatment is to make the microbial flora grow and metabolize, and activate the microbial flora of the sandification soil.

[0036] The present application discloses the following technical effects:

[0037] The soil conditioner prepared by the present application is applied to the sandification soil, the straw carbon adsorbs the microbial agent, the conditions for the growth and metabolism of the microorganism are provided by humic acid and the like, the structure of the sandification soil can be improved, the soil aggregation capacity is improved together with the fly ash and the composite polymer, the organic matter content of the soil is increased by the metabolism of the microorganism, the straw carbon, the humic acid and the composite polymer, the soil fertility is improved, and the water retention capacity and the aeration are improved. DETAILED DESCRIPTION

[0038] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present application.

[0039] It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the stated range, and any other stated value or intermediate value in the stated range, is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, preferred methods and materials are described. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the content of the specification and that of any document incorporated herein by reference, the content of the specification prevails.

[0041] Various modifications and changes can be made to the specific embodiments of the present application described in the specification without departing from the scope or spirit of the application. Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application. The specification and examples are illustrative only.

[0042] As used herein, "comprise", "comprising", "having", "including", "contain", "containing", "include" and the like are open-ended terms that are intended to mean including but not limited to.

[0043] The Rhizobium rhizospherum was purchased from the China Center for Type Culture Collection, with a preservation number of CCTCC JB 2008159, and the bacterial content was not less than 10 9 cfu / g.

[0044] The Paenibacillus mucilaginosus was purchased from the China General Microbiological Culture Collection Center, with a preservation number of CGMCC1.16094, and the bacterial content was not less than 10 9 cfu / g.

[0045] The Paenibacillus mucilaginosus was purchased from the China General Microbiological Culture Collection Center, with a preservation number of CGMCC1.16094, and the bacterial content was not less than 10 9 cfu / g.

[0046] The arbuscular mycorrhizal fungi was purchased from the China General Microbiological Culture Collection Center, with a preservation number of CGMCC NO.12157.

[0047] Unless otherwise specified, the room temperature and the normal temperature described in the present application both refer to 25℃.

[0048] In the specific embodiments of the present application:

[0049] The poly-3-hydroxyalkanoate (PHA), the poly-beta-hydroxybutyric acid (PHB), the polylactic acid (PLA) and the poly-ε-caprolactone (PCL) in the degradable resin are all aimed at coating the bentonite to form a dense film impermeable to water, so as to protect the phase change performance of the phase change material sodium phosphate dibasic dodecahydrate, and therefore, in the present application, the selection of the limited degradable resin does not affect the realization of the technical effect, and therefore, the four kinds of degradable resins can be equally replaced.

[0050] The molecular weight of the polylactic acid is 10,000-200,000; the molecular weight of the poly-ε-caprolactone is 10,000-100,000; the molecular weight of the poly-3-hydroxyalkanoate is 1,000-100,000; and the molecular weight of the poly-beta-hydroxybutyric acid is 50,000-100,000.

[0051] The particle size of the bentonite is 5mm-10mm, the porosity is 40%-60%, the pore volume is 0.4-0.6cm 3 / g, and the cation exchange capacity is 50-150meq / 100g.

[0052] The addition amount of the bentonite is not more than the liquid level of the sodium phosphate dibasic dodecahydrate aqueous solution.

[0053] The addition amount of the bentonite loaded with the sodium phosphate dibasic dodecahydrate is not more than the liquid level of the saturated solution.

[0054] The mass ratio of the dodecahydrate disodium hydrogen phosphate and water is 1:1.

[0055] The molecular weight of the polyethylene imine is 20000-25000; and the molecular weight of the polyvinylamine is 10000-15000.

[0056] The straw charcoal is corn straw charcoal, and the particle size is 10-20mm, and the aspect ratio is 3-4.

[0057] Example 1

[0058] Preparation of the soil temperature adjusting particles:

[0059] The dodecahydrate disodium hydrogen phosphate is dissolved in water to obtain a dodecahydrate disodium hydrogen phosphate aqueous solution, and then the bentonite particles are added, and after slow stirring for 30-60min, the solid-liquid separation is performed to obtain a solid product;

[0060] The solid product is air-dried at room temperature to obtain the bentonite loaded with the dodecahydrate disodium hydrogen phosphate;

[0061] The polylactic acid is dissolved in chloroform at room temperature to prepare a saturated solution of the polylactic acid, and then the bentonite loaded with the dodecahydrate disodium hydrogen phosphate is added into the saturated solution, and after stirring, the chloroform is removed to obtain the soil temperature adjusting particles.

[0062] Example 2

[0063] Preparation of the desertification soil improver:

[0064] The raw materials are: 100 parts of the soil temperature adjusting particles prepared in Example 1, 100 parts of straw charcoal, 40 parts of fly ash, 30 parts of humic acid, 20 parts of a composite polymer, and 4 parts of a composite microbial agent; the composite polymer is composed of polyethylene imine and polyvinylamine, and the mass ratio is 1:1; the composite microbial agent is composed of Azotobacter chroococcum, Bacillus mucilaginosus, Bacillus megaterium, and arbuscular mycorrhizal fungi, and the mass ratio is 1:1.

[0065] The preparation steps are: the composite microbial agent, the humic acid, and the straw charcoal are mixed and stirred uniformly, and then are left to stand for 3h, and then the fly ash, the composite polymer, and the soil temperature adjusting particles are added, and after mixing, the desertification soil improver is obtained.

[0066] Example 3

[0067] Preparation of the desertification soil improver:

[0068] The raw materials are 50 parts of the soil temperature adjusting particles prepared in Example 1, 120 parts of straw charcoal, 60 parts of fly ash, 40 parts of humic acid, 30 parts of a composite polymer, and 5 parts of a composite microbial agent; the composite polymer is composed of polyethyleneimine and polyvinylamine at a mass ratio of 1:1; and the composite microbial agent is composed of Azotobacter chroococcum, Bacillus mycoides, Bacillus megaterium, and arbuscular mycorrhizal fungi at an equal mass ratio.

[0069] The preparation steps are as follows: the composite microbial agent, the humic acid, and the straw charcoal are uniformly mixed and stirred, and then allowed to stand for 2 h; then the fly ash, the composite polymer, and the soil temperature adjusting particles are added and uniformly mixed to obtain the sandy soil improver.

[0070] Example 4

[0071] Preparation of the sandy soil improver:

[0072] The raw materials are 80 parts of the soil temperature adjusting particles prepared in Example 1, 100 parts of straw charcoal, 50 parts of fly ash, 20 parts of humic acid, 30 parts of a composite polymer, and 2 parts of a composite microbial agent; the composite polymer is composed of polyethyleneimine and polyvinylamine at a mass ratio of 1:1; and the composite microbial agent is composed of Azotobacter chroococcum, Bacillus mycoides, Bacillus megaterium, and arbuscular mycorrhizal fungi at an equal mass ratio.

[0073] The preparation steps are as follows: the composite microbial agent, the humic acid, and the straw charcoal are uniformly mixed and stirred, and then allowed to stand for 2 h; then the fly ash, the composite polymer, and the soil temperature adjusting particles are added and uniformly mixed to obtain the sandy soil improver.

[0074] Comparative Example 1

[0075] Compared with Example 2, the only difference is that the soil temperature adjusting particles are replaced by an equal mass of bentonite.

[0076] Comparative Example 2

[0077] Compared with Example 2, the only difference is that the composite polymer is replaced by an equal mass of polyacrylamide.

[0078] Test Example

[0079] The test site is a sandy soil test field in Tongliao City, Inner Mongolia Autonomous Region, wherein the organic matter content of the sandy soil test field is about 2.35%, the total nitrogen content is about 0.39%, the total phosphorus content is about 0.13%, the total potassium content is about 3.4%, the sand content is 42.35%-46.59%, the physical clay with a particle size of less than 0.01 mm is 8.51%-11.73%, and the physical clay with a particle size of less than 0.001 mm is 1.21%-2.95%.

[0080] The test field was divided into 16 test fields which did not interfere with each other, and each test field had an area of 50 m 2 The sandy soil improver prepared by using Examples 2-4 and Comparative Examples 1-2 was applied to each test field, and each sandy soil improver was set up in triplicate. The blank control group (CK) was 1 test field, and the application amount of the sandy soil improver was 600 kg / acre. The application method was as follows: after being uniformly scattered on the surface of the test field, rotary tillage was performed with a rotary tillage depth of 30 cm. After rotary tillage, the test field was leveled, and corn (Zhengdan 958) was sowed after 15 days. The sowing row spacing was 45 cm, the plant spacing was 30 cm, and the sowing depth was 5 cm. The CK group was only subjected to rotary tillage with a rotary tillage depth of 30 cm, and the sowing parameters were consistent with those of the other test fields. The 16 test fields were sowed in the middle of May, the same field management was adopted, and the diurnal temperature difference of each test field was recorded on the 30th day (in the middle of June), the 60th day (in the middle of July), and the 90th day (in the middle of August) after sowing. The average value was calculated, and the results are shown in Table 1. The properties of the 0-30 cm soil layer of the test field were detected after the corn was harvested, and the results are shown in Table 2. The weight of the harvested corn and the weight of the straw are shown in Table 3.

[0081] Table 1

[0082]

[0083] As can be seen from Table 1, the sandy soil improvers containing the soil temperature adjusting particles of Examples 2-4 and Comparative Example 2 have a smaller diurnal temperature difference, while the diurnal temperature difference of the control group without the sandy soil improver is too large. Among them, the 30th day after sowing is in the middle of June, the 60th day after sowing is in the middle of July, and the 90th day after sowing is in the middle of August, and the air temperature gradually rises. Therefore, the data of the control group and Comparative Example 1 show an upward trend. The temperature difference of 30 d and 60 d of Examples 2-3 and Comparative Example 2 is small, while the temperature difference of 90 d is large. The reason is that the outer degradable resin of the soil temperature adjusting particles gradually degrades, causing the swelling clay to lose part of the crystallization water of the phase change material, and the phase change performance decreases, thereby causing the temperature difference of 90 d to increase. Since the highest daytime temperature in June-August can reach 28-35℃, and the nighttime temperature is generally below 20℃, and the temperature of sandy soil can reach above 40℃ in the daytime, the dodecahydrate disodium hydrogen phosphate with a phase change temperature of 36℃ can well control the soil temperature through phase change.

[0084] Table 2

[0085]

[0086]

[0087] As can be seen from Table 2, the application of the prepared soil improver can improve the physical and chemical properties of the soil. In the comparative example 1, the soil temperature adjusting particles are replaced by ordinary bentonite, which has no effect on adjusting the soil temperature, so that the organic matter, moisture and compactness of the soil are lower than those of the examples 2-3. This is because the microbial population in the soil is not well constructed due to the lack of good growth and metabolism conditions, resulting in a smaller increase in organic matter, moisture and compactness. In the comparative example 2, the composite polymer is replaced by polyacrylamide of the same mass fraction, which only has water retention effect. In the present application, the polyethyleneimine is degraded by microorganisms to release organic matter and nutrients, which provides energy and nutrients for the growth and metabolism of microorganisms, and can also combine with soil particles to form stable complexes. Not only can it increase the aggregation and water retention capacity of the soil, but also can improve the structure and fertility of the soil. The polyethyleneamine can combine with the soil particles to form stable complexes, increase the organic matter content of the soil, improve the aggregation and water retention capacity of the soil, promote the absorption and utilization of water and nutrients by plants, and improve the stress resistance and adaptability of plants.

[0088] Table 3

[0089] Dry weight of grain / kg Dry weight of straw / kg Example 2 677.3 1350.5 Example 3 666.7 1286.0 Example 4 670.5 1315.0 Comparative Example 1 535.4 980.5 Comparative Example 2 589.5 1055.3 CK 420.5 757.0

[0090] As can be seen from Table 3, the application of the soil improver in examples 2-4 and comparative examples 1-2 can effectively increase the dry weight of corn kernels and straw, thereby improving the economic benefit per mu. In examples 2-4 and comparative examples 1-2, the improvement effect of examples 2-4 is more significant.

[0091] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0092] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. Application of soil temperature regulating particles in desertified soil conditioner, characterized in that: The soil temperature regulating particles are core-shell particles with bentonite as a carrier, disodium hydrogen phosphate dodecahydrate as a load, and a degradable resin as a coating material; The degradable resin includes one of poly 3-hydroxyalkanoate, poly β-hydroxybutyrate, polylactic acid and poly ε-caprolactone; the bentonite has a particle size of 5 mm to 10 mm, a porosity of 40% to 60%, and a pore volume of 0.4 to 0.6 cm 3 / g, cation exchange capacity is 50~150meq / 100g; The preparation steps of the soil temperature regulating particles include: dissolving disodium hydrogen phosphate dodecahydrate in water to obtain a disodium hydrogen phosphate dodecahydrate aqueous solution, adding bentonite particles, slowly stirring for 30 to 60 minutes, and performing solid-liquid separation to obtain a solid product; air-drying the solid product at room temperature to obtain bentonite loaded with disodium hydrogen phosphate dodecahydrate; dissolving a degradable resin in chloroform at room temperature to obtain a saturated solution of the degradable resin, then adding the bentonite loaded with disodium hydrogen phosphate dodecahydrate to the saturated solution, stirring evenly, and removing the chloroform to obtain the soil temperature regulating particles; The amount of bentonite added is not more than the liquid level of the sodium hydrogen phosphate dodecahydrate aqueous solution; The amount of bentonite loaded with disodium hydrogen phosphate dodecahydrate added does not exceed the liquid level of the saturated solution.

2. The use according to claim 1, characterized in that The mass ratio of the disodium hydrogen phosphate dodecahydrate to water is 1:

1.

3. A desertified soil conditioner, characterized in that: Calculated by mass, the raw materials include: 50-100 parts of the soil temperature regulating particles according to claim 1 or 2, 100-120 parts of straw charcoal, 40-60 parts of fly ash, 20-40 parts of humic acid, 20-30 parts of composite polymer and 2-5 parts of composite bacterial agent; The composite polymer is composed of polyethyleneimine and polyethyleneamine in a mass ratio of 1:1; The composite bacterial agent is prepared by mixing brown spherical nitrogen-fixing bacteria, jelly-like Bacillus, megaterium and arbuscular mycorrhizal fungi in equal mass ratios; The straw charcoal is corn straw charcoal with a particle size of 10-20 mm and an aspect ratio of 3-4.

4. A method for preparing the desertified soil conditioner according to claim 3, characterized in that the steps include: The composite bacterial agent, humic acid and straw charcoal are mixed and stirred evenly, and allowed to stand for 2 to 3 hours. Fly ash, composite polymer and soil temperature regulating particles are added and mixed evenly to obtain the desertified soil improver.

5. Use of the desertified soil conditioner according to claim 3 in the restoration and improvement of desertified soil.

6. The use according to claim 5, characterized in that The application method is as follows: the desertified soil improver is evenly spread on the surface of the desertified soil, followed by rotary tillage treatment, and the land is leveled after the rotary tillage treatment. Conventional crops can be planted after 10 to 15 days.

7. The use according to claim 6, characterized in that The rotary tillage depth is 25-30 cm; the application amount of the desertified soil conditioner is 600-1200 kg / mu.

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