A soil conditioner for soil acidification control and its preparation and application

Abstract

The present invention provides a soil conditioner for soil acidification control and its preparation and application. The preparation method of the soil conditioner is as follows: S1, prepare AEB nanocomposite material, specifically as follows: first prepare modified nano carbon black: specifically, modify nano carbon black to obtain carboxyl modified nano carbon black; then prepare nano lignin solution: mix nano lignin, ethanol and water, and stir well to obtain; finally, add attapulgite and the prepared modified nano carbon black to the prepared nano lignin solution, stir well and ultrasonically treat, and then dry and grind to obtain AEB nanocomposite material; S2, mix the AEB nanocomposite material with dolomite powder in proportion to obtain. The soil conditioner prepared by the present invention has a fast onset of action and a high soil pH buffering capacity. It can fundamentally and comprehensively control acidified soil, and is not prone to re-acidification and soil compaction. The yield-increasing effect is more significant when combined with the application of organic fertilizer.

Description

Technical Field

[0001] The present invention relates to the technical field of soil acidification control, and in particular to a soil conditioner for soil acidification control and a preparation and application thereof. Background Art

[0002] Soil acidification has become one of the most serious land degradation problems in the global agricultural system, with up to 30% of the world's arable land affected by acidification. Soil acidification first affects the effectiveness of soil nutrients; at the same time, soil acidification will accelerate the weathering of primary and secondary aluminum-containing minerals in the soil and release a large amount of aluminum ions, forming aluminum compounds that can be absorbed by plants. Long-term and excessive absorption of aluminum ions by plants will cause crop poisoning or death, resulting in a large reduction in crop yields or even crop failure; secondly, soil acidification will affect the activity of soil enzymes, thereby affecting the absorption of nutrients by crops; finally, soil acidification will also lead to a large loss of alkaline base ions such as calcium and magnesium, which will lead to the deterioration of soil physical and chemical properties, change soil structure, and reduce soil buffering performance.

[0003] At present, many scholars in my country have carried out research on soil acidification improvement. For example, some studies have adopted measures such as returning straw to the fields, planting green manure, and increasing organic fertilizer to increase soil buffering capacity and effectively alleviate the decline in soil pH. They also use chemical improvers such as lime, fly ash and other industrial by-products to improve soil acidification.

[0004] The existing Chinese patent document CN111233571A discloses a soil conditioner, which is a mixture of seaweed residue fermented by microorganisms, carbonized bagasse, carbonized sugarcane leaves, bone char, sugar factory filter mud, silicon potash fertilizer and attapulgite, and then dried, crushed and stirred. The soil conditioner can solve the soil acidification caused by the long-term use of chemical fertilizers and acid rain deposition and other types of acidification problems.

[0005] Existing Chinese patent document CN118085878A provides a conditioner for targeted repair of acidified black soil. The particles of the conditioner include a core layer and a shell layer. The core layer includes alginate, biochemical fulvic acid and lignin, and the shell layer includes a KH2PO4 solution and low-temperature roasted oyster shell powder. The acidified black soil can be targetedly repaired through the interaction of the components.

[0006] The existing Chinese patent document CN106116939A discloses a soil acidification repair agent, which is composed of raw materials in mass ratio: 40%-80% calcium cyanamide, 5%-30% humic acid, 5%-20% calcium magnesium phosphate fertilizer, 5%-20% dolomite powder, 1%-10% silicon dioxide, and 1%-8% boron fertilizer. The soil repair agent can increase the soil pH value to above 1.0 and can be used for soil acidification conditioning, soil disinfection, and continuous cropping obstacle control of facility vegetables.

[0007] However, all of the above-mentioned soil acidification remediation agents have problems to some extent, such as slow onset of effect, poor expansion of acid buffer capacity, re-acidification, and frequent soil compaction.

[0008] Therefore, there is an urgent need to develop a soil acidification remediation agent that has a fast onset of action, a high soil pH buffering capacity, can fundamentally and comprehensively treat acidified soil, and is not prone to re-acidification and soil compaction. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a soil conditioner for soil acidification control and its preparation and application. The purpose is to solve the problems of existing soil conditioners, such as slow onset of action, small soil pH buffering capacity, easy occurrence of re-acidification and soil compaction after application, and inability to fundamentally and comprehensively control acidified soil.

[0010] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a method for preparing a soil conditioner for soil acidification control, which specifically comprises the following steps:

[0012] S1. Prepare AEB nanocomposite materials as follows:

[0013] S101, first preparing modified nano carbon black: modifying nano carbon black to obtain carboxyl modified nano carbon black; the modification temperature is 50-80°C, and the time is 2-4h;

[0014] S102, then preparing a nano-lignin solution: mixing and dissolving the nano-lignin, ethanol and water, and stirring them thoroughly; wherein the mass ratio of the nano-lignin, ethanol and water is: 1-2:1-2:6-8;

[0015] S103, finally adding attapulgite and the modified nano carbon black prepared in S101 to the nano lignin solution prepared in S102, the mass ratio of attapulgite, modified nano carbon black and nano lignin solution being 3-4:1-2:5-10; after sufficient stirring and ultrasonic treatment, drying and grinding to obtain the AEB nano composite material;

[0016] S2. According to the mass ratio of AEB nanocomposite material to dolomite powder of 5-7:3-5, the AEB nanocomposite material and dolomite powder are mixed to obtain the soil conditioner for soil acidification control.

[0017] Furthermore, carboxyl-modified nano-carbon black is obtained by mixing and modifying the nano-carbon black with concentrated nitric acid or potassium permanganate or a mixture of concentrated nitric acid and potassium permanganate.

[0018] Preferably, in step S101, the carboxyl-modified nano-carbon black is obtained by mixing and modifying the nano-carbon black with concentrated nitric acid. Preferably, the mass ratio of the nano-carbon black to the concentrated nitric acid is 1-4:4-8.

[0019] Furthermore, in step S101, the particle size of the nano carbon black is 20-70 nm.

[0020] Furthermore, in step S102, the particle size of the nano-lignin is 30-60 nm.

[0021] Furthermore, the conditions of the ultrasonic treatment in step S103 are: the ultrasonic treatment temperature is 30-50° C., and the ultrasonic frequency is 600-800 kHz.

[0022] Furthermore, the drying in step S103 is preferably freeze-drying, and the freeze-drying time is 2 to 4 hours.

[0023] Furthermore, in step S103, the particle size of the attapulgite is 100-200 mesh, and the pH value is ≥9.0.

[0024] Furthermore, in the dolomite powder of step S2: CaO ≥ 30%, MgO ≥ 20%, pH ≥ 10.0, 100-200 mesh.

[0025] In a second aspect, the present invention provides a soil conditioner for soil acidification control obtained by the above preparation method.

[0026] In a third aspect, the present invention also provides the use of the soil conditioner prepared by the above method in soil acidification control.

[0027] Furthermore, the application method is as follows: 10 to 15 days before crop planting, 200 to 400 kg / mu of the soil conditioner is evenly spread on the soil surface, and the soil is tilled and mixed evenly.

[0028] Furthermore, the application also includes applying 50-100 kg / mu of organic fertilizer before spreading the alkaline soil conditioner.

[0029] The present invention has the following beneficial effects:

[0030] The soil conditioner for soil acidification treatment provided by the invention is prepared with nano black carbon, nano lignin, attapulgite and dolomite powder as raw materials.

[0031] (1) Nano-lignin has good cation exchange and complexing properties and has rich functional groups, such as hydroxyl and carboxyl groups, so it can effectively improve the utilization efficiency of soil nutrients by plants, improve soil aggregate structure and soil enzyme activity, and to a certain extent increase soil pH. In the preparation process of the present invention, the nano-lignin is first processed into a nano-lignin solution so that the nano-lignin is well dissolved in ethanol, so that the nano-lignin can be better loaded on attapulgite.

[0032] (2) Nano carbon black can adsorb and fix acidic substances in the soil due to its porosity and high specific surface area, and can increase the soil pH value to a certain extent while increasing the soil's acid-resistant buffering capacity. It also has the functions of providing nutrients, reducing nutrient loss, increasing soil enzyme activity, enhancing plant stress resistance, and promoting plant growth and development. In the preparation method of the present invention, nano carbon black is first modified into carboxyl-modified nano carbon black, which can further increase its surface conservation functional groups, improve surface properties, and improve its adsorption efficiency and stability; at the same time, the modification can reduce the mobility of nano carbon black in the soil.

[0033] (3) Attapulgite has strong adsorption, ion exchange and high cation exchange capacity, which can react with hydrogen ions (H + ) and aluminum ions (Al 3+ ) to exchange, releasing alkaline ions (such as calcium ions Ca 2+ 、Magnesium ion Mg 2+ etc.), thereby neutralizing the acidic substances in the soil and increasing the pH value of the soil.

[0034] At the same time, as an environmentally friendly natural clay material, attapulgite has a nano-network structure and contains a large number of micro-nanopores. In the preparation method of the present invention, attapulgite and modified nano-carbon black are stirred with a nano-lignin solution, ultrasonically treated and dried to obtain an AEB nano-composite material. In this process, attapulgite can provide a stable carrier environment for nano-lignin and nano-carbon black, effectively preventing the agglomeration of nano-lignin and nano-carbon black in the soil and thus causing inactivation. The prepared attapulgite loaded with nano-lignin and nano-carbon black, the three materials synergize and interact with each other, and can achieve the effect of 1+1+1>3 in terms of improving soil pH and soil acid-base buffer capacity (pHBC), reducing soil exchangeable hydrogen and aluminum, improving soil enzyme activity, reducing nutrient loss, and promoting nutrient effectiveness.

[0035] (4) Dolomite powder is mainly composed of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3), both of which have strong alkalinity. When dolomite powder is applied to acidic soil, the carbonate ions (CO3 2- ) will react with acidic ions in the soil (such as H +) to produce carbon dioxide (CO2) and water (H2O), thereby consuming the acidic substances in the soil and increasing the pH value of the soil. 2+ ) and magnesium ions (Mg 2+ ) can replace the acid-causing ions adsorbed on the soil colloid (such as aluminum ions Al 3+ 、H + This cation exchange not only helps to increase the pH value of the soil, but also improves the physical and chemical properties of the soil and promotes the recovery of soil fertility.

[0036] In summary, the soil conditioner provided by the present invention has the following technical advantages:

[0037] Firstly, the soil conditioner provided by the present invention has the advantages of being able to comprehensively treat acidified soil, from directly and significantly increasing soil pH, to indirectly increasing soil pH buffering capacity, and to fundamentally reducing the content of acidogenic ions such as exchangeable hydrogen and aluminum in the soil.

[0038] Secondly, in terms of soil improvement, the present invention can increase soil enzyme activity, reduce nutrient loss, and improve nutrient effectiveness. In terms of crops, it can promote crop nutrient absorption, improve crop stress resistance, and promote plant growth and development. It can exert force from soil to crops in a three-dimensional manner to eliminate the adverse effects of soil acidification.

[0039] Furthermore, the raw materials used in the soil conditioner provided by the present invention are all good environmentally friendly materials, especially nano-lignin and nano-black carbon, which have good biodegradability, leave little residue in the soil, and cause little secondary pollution to the environment.

[0040] In summary, the soil conditioner provided by the present invention, based on the principle and harm of soil acidification, can effectively alleviate a series of problems caused by soil acidification by improving soil pH, soil acid-base buffer capacity (pHBC), soil nutrient effectiveness and soil enzyme activity, and reducing soil aluminum activation, and can provide strong support for soil acidification control. Compared with traditional control methods, it has the advantages of fast effect, comprehensive effect, good buffer capacity and nutrient expansion effect, and is not prone to re-acidification and soil compaction. DETAILED DESCRIPTION

[0041] As used herein:

[0042] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0043] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0044] When each parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0045] In these examples, parts and percentages are by mass unless otherwise indicated.

[0046] "Weight parts" / "mass parts" refers to the basic measurement unit that indicates the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2g. If we say that the mass parts of component A are a parts and the mass parts of component B are b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0048] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0049] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0050] The raw materials and their sources used in the following examples are as follows:

[0051] Attapulgite: purchased from Hongcheng Ore Powder Co., Ltd., 100~200 mesh, pH value ≥9.0.

[0052] Nano-lignin: Hunan Wanmufeng Agricultural Technology Co., Ltd., particle size is 30~60nm.

[0053] Nano carbon black: purchased from Jinan Tiancheng Carbon Black Factory, with a particle size of 20~70nm.

[0054] Dolomite powder: purchased from Hongcheng Ore Powder Co., Ltd., CaO ≥ 30%, MgO ≥ 20%, pH ≥ 10.0, 100~200 mesh.

[0055] 1. Preparation of AEB nanocomposites

[0056] Example 1

[0057] This embodiment provides a method for preparing an AEB nanocomposite material, comprising the following steps:

[0058] (1) First prepare modified nano-carbon black: according to the mass ratio of nano-carbon black to concentrated nitric acid (3 mol / L) of 1:2, mix nano-carbon black and concentrated nitric acid to obtain carboxyl-modified nano-carbon black; the modification temperature is 60 ° C and the time is 4 h.

[0059] (2) Then prepare the nano-lignin solution: according to the mass ratio of nano-lignin, ethanol and water being 2:2:6, mix the nano-lignin, ethanol and water and stir them thoroughly.

[0060] (3) Finally, attapulgite and the modified nano carbon black prepared in (1) were added to the nano lignin solution prepared in (2), and the mass ratio of attapulgite, modified nano carbon black and nano lignin solution was 3:2:10; after sufficient stirring and ultrasonic treatment, the AEB nanocomposite material was obtained by freeze drying and grinding. The ultrasonic treatment temperature was 50°C, the ultrasonic frequency was 800 kHz, and the freeze drying time was 4 hours.

[0061] Example 2

[0062] This embodiment provides a method for preparing an AEB nanocomposite material, comprising the following steps:

[0063] (1) First prepare modified nano-carbon black: according to the mass ratio of nano-carbon black to concentrated nitric acid (3 mol / L) of 1:4, nano-carbon black and concentrated nitric acid are mixed and modified to obtain carboxyl-modified nano-carbon black; the modification temperature is 50°C and the time is 4 h.

[0064] (2) Then prepare the nano-lignin solution: according to the mass ratio of nano-lignin, ethanol and water being 1:1:6, mix the nano-lignin, ethanol and water and stir them thoroughly.

[0065] (3) Finally, attapulgite and the modified nano carbon black prepared in (1) were added to the nano lignin solution prepared in (2), and the mass ratio of attapulgite, modified nano carbon black and nano lignin solution was 3:1:5; after sufficient stirring and ultrasonic treatment, the AEB nanocomposite material was obtained by freeze drying and grinding. The ultrasonic treatment temperature was 30°C, the ultrasonic frequency was 600 kHz, and the freeze drying time was 2 h.

[0066] Example 3

[0067] This embodiment provides a method for preparing an AEB nanocomposite material, comprising the following steps:

[0068] (1) First prepare modified nano-carbon black: according to the mass ratio of nano-carbon black to concentrated nitric acid (3 mol / L) of 2:6, mix nano-carbon black and concentrated nitric acid to obtain carboxyl-modified nano-carbon black; the modification temperature is 80 °C and the time is 2 h.

[0069] (2) Then prepare the nano-lignin solution: according to the mass ratio of nano-lignin, ethanol and water being 2:2:8, mix the nano-lignin, ethanol and water and stir them thoroughly.

[0070] (3) Finally, attapulgite and the modified nano carbon black prepared in (1) were added to the nano lignin solution prepared in (2), and the mass ratio of attapulgite, modified nano carbon black and nano lignin solution was 4:2:8; after sufficient stirring and ultrasonic treatment, the AEB nanocomposite material was obtained by freeze drying and grinding. The ultrasonic treatment temperature was 40°C, the ultrasonic frequency was 700 kHz, and the freeze drying time was 3 h.

[0071] 2. Preparation of soil conditioner

[0072] Example 4

[0073] This embodiment provides a method for preparing a soil conditioner, specifically, the AEB nanocomposite material prepared in Example 1 is mixed with dolomite powder to obtain the soil conditioner. The mass ratio of the AEB nanocomposite material to the dolomite powder is 7:3.

[0074] Example 5

[0075] This embodiment provides a method for preparing a soil conditioner, specifically, the AEB nanocomposite material prepared in Example 1 is mixed with dolomite powder to obtain the soil conditioner. The mass ratio of the AEB nanocomposite material to the dolomite powder is 5:5.

[0076] Example 6

[0077] This embodiment provides a method for preparing a soil conditioner, specifically, the AEB nanocomposite material prepared in Example 1 is mixed with dolomite powder to obtain the soil conditioner. The mass ratio of the AEB nanocomposite material to the dolomite powder is 4:6.

[0078] Example 7

[0079] This embodiment provides a method for preparing a soil conditioner, specifically, the AEB nanocomposite material prepared in Example 2 is mixed with dolomite powder to obtain the soil conditioner. The mass ratio of the AEB nanocomposite material to the dolomite powder is 7:3.

[0080] Example 8

[0081] This embodiment provides a method for preparing a soil conditioner, specifically, the AEB nanocomposite material prepared in Example 3 is mixed with dolomite powder to obtain the soil conditioner. The mass ratio of the AEB nanocomposite material to the dolomite powder is 7:3.

[0082] 3. Comparative test on application of soil conditioners

[0083] 1. Application Example 1

[0084] To verify the effects of each component, the present invention conducted the following soil cultivation test: Soil from a paddy field in Ningxiang, Hunan was selected, naturally air-dried and then passed through a 10-mesh sieve, the pH was adjusted to 4.5 by using a 1 mol / L HCl solution, then naturally air-dried, and then packaged into plastic barrels at 2 kg / barrel.

[0085] The experiment set up 13 treatments:

[0086] Treatment 1: attapulgite, 2% addition of soil mass;

[0087] Treatment 2: nano-lignin, 2% of soil mass added;

[0088] Treatment 3: modified nano carbon black, 2% of soil mass added;

[0089] Treatment 4: AEB nanocomposite prepared in Example 1, added in an amount of 2% by mass of soil;

[0090] Treatment 5: AEB nanocomposite prepared in Example 2, added in an amount of 2% by mass of soil;

[0091] Treatment 6: AEB nanocomposite prepared in Example 3, added in an amount of 2% by mass of soil;

[0092] Treatment 7: dolomite powder, 2% of soil mass;

[0093] Treatment 8: alkaline soil conditioner prepared in Example 4, added in an amount of 2% of soil mass;

[0094] Treatment 9: alkaline soil conditioner prepared in Example 5, added in an amount of 2% of soil mass;

[0095] Treatment 10: alkaline soil conditioner prepared in Example 6, added in an amount of 2% of soil mass;

[0096] Treatment 11: alkaline soil conditioner prepared in Example 7, added in an amount of 2% by weight of the soil;

[0097] Treatment 12: alkaline soil conditioner prepared in Example 8, added in an amount of 2% of soil mass;

[0098] Treatment 13: Blank control, no other substances were added.

[0099] After each treatment was mixed evenly, an appropriate amount of water was added until the field water capacity reached 60%. The plastic bucket was placed in a constant temperature and humidity incubator (HWS-150b) for 60 days, during which water was regularly added to maintain soil moisture content.

[0100] Afterwards, soil samples from each treatment were taken for index determination, including soil pH (electrode method), acid-base buffer capacity (pHBC) (pH acidometer method), exchangeable hydrogen and exchangeable aluminum (potassium chloride exchange-neutralization titration method) to evaluate the effects of each component and alkaline conditioner. The specific results are shown in Table 1.

[0101] Table 1 Effects of different treatments on soil acidification indicators in Application Example 1

[0102]

[0103] It can be seen from Table 1 that the AEB nanocomposite material prepared in the present invention can more effectively increase soil pH and pHBC, and reduce soil exchangeable hydrogen and exchangeable aluminum content, compared with the application of its components alone, among which Example 1 has the best effect.

[0104] Compared with dolomite powder, AEB nanocomposite materials have similar effects on the improvement of soil pH and pHBC, but AEB reduces soil exchangeable hydrogen significantly more than dolomite powder, while dolomite powder reduces exchangeable aluminum significantly more than AEB. Therefore, in the subsequent soil acidification control process, the proportion of the two can be adjusted as appropriate according to the actual exchangeable hydrogen and exchangeable aluminum contents in the soil.

[0105] Compared with the application of AEB nanocomposite materials and dolomite powder alone, the soil conditioner prepared in the embodiment of the present invention has a more significant control effect on the acidification index. Therefore, the application effect of each component of the soil conditioner prepared in the embodiment of the present invention in soil acidification control has an effect of 1+1>2.

[0106] 2. Application Example 2

[0107] A field with a flat terrain and an area of ​​about 1 mu was selected in a township in Qiyang City, Hunan Province for the effect verification test of the soil conditioner of the present invention on soil acidification control. The test was set up with 3 treatments, each treatment was repeated 3 times, and a total of 9 plots were set up. A 2.5-meter-wide protection row was set up around the test area. At the same time, a ridge (20 cm wide and 30 cm high) was set between every two plots, and a plastic film was covered on the ridge to prevent water and fertilizer from flowing into different plots. The plots were arranged in random blocks.

[0108] Treatment 1: Blank (CK), conventional fertilization (application of 51% (26-10-15) compound fertilizer 225 kg / hm 2 As base fertilizer), without applying any soil conditioner;

[0109] Treatment 2: conventional fertilization (application of 51% (26-10-15) compound fertilizer 225 kg / hm 2 As base fertilizer + soil conditioner prepared in Example 4 200 kg / mu;

[0110] Treatment 3: conventional fertilization (application of 51% (26-10-15) compound fertilizer 225 kg / hm 2 As base fertilizer + soil conditioner prepared in Example 4 400 kg / mu;

[0111] 10-15 days before rice planting, after spreading fertilizer, evenly spread soil conditioner on the field surface, then mix the soil conditioner with the soil through plowing, and pour in appropriate amount of water for maturation. Later, transplant Longliangyou 1212 rice varieties uniformly, with a transplanting row spacing of 20 cm × 25 cm, and the field water management and fertilization conditions are consistent with local management conditions.

[0112] Before the experiment, mixed samples of 5 to 6 sampling points were collected from the entire experimental field as the basic soil samples for the experiment and sent to Zhejiang Zhenong Testing and Certification Technology Co., Ltd. to measure the physical and chemical properties including soil pH (electrode method), acid-base buffer capacity (pHBC) (pH acidometer method), exchangeable hydrogen and exchangeable aluminum (potassium chloride exchange-neutralization titration method). The test results are shown in Table 2. After the experiment, mixed samples of 5 to 6 sampling points were collected from each plot and sent to Zhejiang Zhenong Testing and Certification Technology Co., Ltd. to measure soil pH, pHBC, exchangeable hydrogen, exchangeable aluminum, effective nitrogen (acid hydrolysis method), available potassium (NY / T 889), effective phosphorus (NY / T1121.7), soil urease (sodium phenol-sodium hypochlorite colorimetric method), catalase (potassium permanganate titration method), sucrase (3,5-dinitrosalicylic acid colorimetric method), phosphatase (disodium phenyl phosphate colorimetric method) and other indicators. When the rice was harvested, the plots were harvested, dried and weighed separately to calculate the yield.

[0113] Table 2 Soil indexes before the test of Application Example 2

[0114]

[0115] Main results analysis:

[0116] (1) Effects of different treatments on soil pH, pHBC, exchangeable hydrogen and exchangeable aluminum content

[0117] The effects of different treatments on soil pH, pHBC, exchangeable hydrogen and exchangeable aluminum content are shown in Table 3 below.

[0118] Table 3 Effects of different treatments in Application Example 2 on soil acidification indicators

[0119]

[0120] It can be seen from the data in Table 3 that compared with treatment 1, soil pH and pHBC in treatment 2 increased by 10.7% and 41.8%, respectively, and exchangeable hydrogen and exchangeable aluminum contents decreased by 60.9% and 60.3%, respectively. Compared with treatment 1, soil pH and pHBC in treatment 3 increased by 17.7% and 73.5%, respectively, and exchangeable hydrogen and exchangeable aluminum contents decreased by 80.4% and 84.1%, respectively. This shows that the soil conditioner prepared by the present invention can effectively increase soil pH and has a direct treatment effect on acidified soil; it can effectively increase pHBC and reduce the occurrence of re-acidification, and has an indirect treatment effect on acidified soil; at the same time, it can also effectively reduce the exchangeable hydrogen and exchangeable aluminum contents in the soil, thereby reducing the potential acidity of the soil, and has a fundamental treatment effect on acidified soil.

[0121] (2) Effects of different treatments on soil nutrient content

[0122] The effects of different treatments on soil nutrients are shown in Table 4 below.

[0123] Table 4 Effects of different treatments in Application Example 2 on soil acidification indicators

[0124]

[0125] From the data in Table 4 above, it can be seen that compared with treatment 1 (CK), alkaline-hydrolyzed nitrogen, available potassium and available phosphorus in treatment 2 increased by 12.8%, 13.3% and 42.5% respectively; compared with treatment 1 (CK), alkaline-hydrolyzed nitrogen, available potassium and available phosphorus in treatment 3 increased by 22.6%, 27.2% and 60.1% respectively. This shows that the soil conditioner prepared by the present invention can significantly improve the effectiveness of soil nutrients.

[0126] (3) Effects of different treatments on soil enzyme activities

[0127] The effects of different treatments on soil enzyme activities are shown in Table 5 below.

[0128] Table 5 Effects of different treatments in Application Example 2 on soil enzyme activity

[0129]

[0130] From the data in Table 5, it can be seen that compared with treatment 1 (CK), urease, catalase, sucrase and phosphatase in treatment 2 increased by 50.0%, 20.6%, 21.9% and 11.1%, respectively; compared with treatment 1 (CK), urease, catalase, sucrase and phosphatase in treatment 3 increased by 75.0%, 31.3%, 38.5% and 17.2%, respectively. This shows that the soil conditioner prepared by the present invention can significantly improve the activity of soil enzymes.

[0131] (4) Effects of different treatments on rice yield

[0132] The effects of different treatments on rice yield are shown in Table 6 below.

[0133] Table 6 Effects of different treatments in Application Example 2 on rice yield

[0134]

[0135] From the data in Table 6, it can be seen that compared with treatment 1 (CK), the rice yield of treatment 2 and treatment 3 increased by 7.4% and 8.7% respectively. This shows that the soil conditioner prepared by the present invention can significantly increase the rice yield when applied on acidic soil.

[0136] (5) Effects of different treatments on rice traits

[0137] The effects of different treatments on rice traits are shown in Table 7 below.

[0138] Table 7 Effects of different treatments in Application Example 2 on economic traits of mid-season rice

[0139]

[0140] From the data in Table 7, we can see that compared with treatment 1 (CK), the average plant height of treatments 2 and 3 increased by 4.6-6.2 cm, and the number of effective ears increased by 3,000-4,000 ears / 667 m. 2 The total number of grains per ear increased by 4.4 to 6.7 grains, the number of filled grains increased by 6.3 to 8.0 grains, the fruit setting rate increased by 1.7 to 1.9 percentage points, and the thousand-grain weight was 0.2 g. This shows that the soil conditioner prepared by the present invention can promote the growth and development of crops and improve their stress resistance.

[0141] 3. Application Example 3

[0142] A field with a flat terrain and an area of ​​about 0.5 mu was selected in a township in Ningxiang City, Hunan Province for the verification test of the effect of the soil conditioner prepared by the present invention and the application of organic fertilizer on rice yield increase. The test set up 2 treatments, each treatment was repeated 3 times, and a total of 6 plots were set. A 2.5-meter-wide protection row was set around the test area. At the same time, a ridge (20 cm wide and 30 cm high) was set between every two plots, and a plastic film was covered on the ridge to prevent water and fertilizer from flowing into different plots, and the plots were arranged in random blocks.

[0143] Treatment 1: Blank (CK), conventional fertilization (application of 51% (26-10-15) compound fertilizer 225 kg / hm 2 As base fertilizer + 200 kg / mu of alkaline soil conditioner prepared in Example 4;

[0144] Treatment 2: applying 100 kg of organic fertilizer + 200 kg / mu of alkaline soil conditioner prepared in Example 4;

[0145] 10-15 days before rice planting, after spreading organic fertilizer and chemical fertilizer, evenly spread alkaline soil conditioner on the field surface, then mix the alkaline soil conditioner with the soil through plowing, and pour in appropriate amount of water for maturation. Later, uniformly transplant the Huazhan rice variety, with a transplanting row spacing of 20 cm × 25 cm, and the field water management and fertilization conditions are consistent with the local management conditions.

[0146] When harvesting rice, each rice is harvested separately, dried separately, and weighed separately to calculate the yield.

[0147] The main results are analyzed as follows:

[0148] (1) Effects of different treatments on rice yield

[0149] The effects of different treatments on rice yield are shown in Table 8 below.

[0150] Table 8 Effects of different treatments in Application Example 3 on rice yield

[0151]

[0152] From the data in Table 8, it can be seen that the rice yield of treatment 2 increased by 12.7% compared with treatment 1 (CK). This shows that the alkaline soil conditioner prepared by the present invention has a more significant effect on increasing rice yield when applied in combination with organic fertilizer on acidic soil.

[0153] In summary, the soil conditioner for acidification control prepared by the present invention has been verified in the above-mentioned application example 1 that each component has a certain effect on acidification control, and through the preparation method of the present invention, the application effect of each component in soil acidification control is achieved to have an effect of 1+1>2. The alkaline soil conditioner prepared by the present invention can effectively increase the soil pH, has a direct control effect on acidified soil, can effectively increase pHBC, reduce the phenomenon of repeated acidification, and has an indirect control effect on acidified soil. At the same time, it can effectively reduce the exchangeable hydrogen and exchangeable aluminum content of the soil, thereby reducing the potential acidity of the soil, and has a fundamental control effect on acidified soil. At the same time, the alkaline soil conditioner prepared by the present invention improves the effectiveness of soil nutrients and enzyme activity, promotes crop nutrient absorption, promotes plant growth and development, etc., and performs soil-plant three-dimensional force to eliminate the adverse effects of soil acidification and increase crop yields.

[0154] In addition, the alkaline soil conditioner prepared by the present invention is applied in combination with organic fertilizer, which has a more significant effect on increasing crop yield.

[0155] The above descriptions are only some preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a soil conditioner for soil acidification control, characterized in that: The specific steps include: S1. Prepare AEB nanocomposite materials as follows: S101, first preparing modified nano carbon black: obtaining carboxyl modified nano carbon black by mixing and modifying nano carbon black with concentrated nitric acid; the mass ratio of nano carbon black to concentrated nitric acid is 1-4:4-8; the modification temperature is 50-80°C, and the modification time is 2-4h; S102, then preparing a nano-lignin solution: mixing and dissolving the nano-lignin, ethanol and water, and stirring them thoroughly; wherein the mass ratio of the nano-lignin, ethanol and water is: 1-2:1-2:6-8; S103, finally adding attapulgite and the modified nano carbon black prepared in S101 to the nano lignin solution prepared in S102, the mass ratio of attapulgite, modified nano carbon black and nano lignin solution is: 3~4:1~2:5~10; after sufficient stirring and ultrasonic treatment, the AEB nano composite material is obtained by drying and grinding; the conditions of ultrasonic treatment are: ultrasonic treatment temperature is 30~50℃, and ultrasonic frequency is 600~800kHZ; S2. According to the mass ratio of AEB nanocomposite material to dolomite powder of 5-7:3-5, the AEB nanocomposite material and dolomite powder are mixed to obtain the soil conditioner for soil acidification control.

2. The method for preparing a soil conditioner for soil acidification control according to claim 1, characterized in that: In step S101, the particle size of the nano carbon black is 20-70 nm; in step S102, the particle size of the nano lignin is 30-60 nm.

3. The method for preparing a soil conditioner for soil acidification control according to claim 1, characterized in that: In step S103, the drying method is freeze drying, and the freeze drying time is 2 to 4 hours.

4. The method for preparing a soil conditioner for soil acidification control according to claim 1, characterized in that: In step S103, the particle size of the attapulgite is 100-200 mesh, and the pH value is ≥9.

0.

5. The method for preparing a soil conditioner for soil acidification control according to claim 1, characterized in that: In the dolomite powder of step S2: CaO ≥ 30%, MgO ≥ 20%, pH ≥ 10.0, 100-200 mesh.

6. A soil conditioner for soil acidification control obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the soil conditioner according to claim 6 in soil acidification control, characterized in that: The application method is as follows: 10 to 15 days before crop planting, 200 to 400 kg / mu of the soil conditioner is evenly spread on the soil surface, and the soil is tilled and mixed evenly.

8. The use according to claim 7, characterized in that The application also includes applying 50-100 kg / mu of organic fertilizer before spreading the alkaline soil conditioner.

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