Acid-adjusting and stabilizing functional organic fertilizer for red soil and preparation method thereof

Abstract

The application provides a red soil acid-adjusting and stabilizing functional organic fertilizer and a preparation method thereof, and relates to the technical field of acid red soil improvement. The organic fertilizer is composed of lime, potassium fulvic acid, tobacco waste root fermentation material, rotten straw manure, modified diatomite and graded particle size zeolite. The tobacco waste root fermentation material is obtained by roasting tobacco waste roots, grinding into powder, inoculating penicillium for fermentation, sterilizing treatment and subsequent inoculation of kluyveromyces marxianus for fermentation treatment. The modified diatomite is obtained by mixing diatomite with an ethanol solution of lauryl glucoside after acid washing, fully mixing and drying. The application overcomes the shortcomings of the prior art, designs efficient and stable improvement materials suitable for red soil, and provides scientific basis and technical support for red soil acidification improvement practice.

Description

Technical Field

[0001] This invention relates to the field of acid red soil improvement technology, specifically to a functional organic fertilizer for red soil that adjusts and stabilizes acidity and its preparation method. Background Technology

[0002] Red soil acidification is one of the main problems of soil degradation in the red soil region of southern my country. Increased soil acidity damages soil structure, reduces soil fertility, inhibits crop growth, and seriously restricts sustainable agricultural development. Applying alkaline amendments is a key technical measure to regulate red soil acidity and improve soil quality. Its core function is to neutralize soil acidity, improve soil acid buffering capacity, and improve soil physical and chemical properties.

[0003] The main existing method for adjusting soil acidification is to apply lime for improvement. Although lime can quickly adjust acidification, it is prone to compaction, phosphorus fixation, acid reversion, and has no fertilization effect. Therefore, it is generally necessary to use a combination of multiple raw materials to improve the overall soil acidification adjustment effect. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a functional organic fertilizer for regulating and stabilizing acidity in red soil and its preparation method. It designs a highly efficient and stable improvement material suitable for red soil, providing a scientific basis and technical support for the practice of red soil acidification improvement.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A functional organic fertilizer for red soil that adjusts and stabilizes acidity, the organic fertilizer is composed of the following raw materials in parts by weight: 30-45 parts lime, 15-25 parts potassium humate, 10-12 parts fermented tobacco waste root material, 18-25 parts decomposed straw manure, 5-10 parts modified diatomite, and 5-8 parts graded zeolite. The fermented tobacco waste root material is prepared by roasting the waste tobacco roots, grinding them into powder, inoculating them with Penicillium mold for fermentation, sterilizing them, and then inoculating them with Kluyveromyces yeast, which is obtained by fermentation for 4-7 days and then drying. The modified diatomaceous earth is prepared by acid washing of diatomaceous earth, mixing it thoroughly with an ethanol solution of lauryl glucoside, and then drying it. The graded particle size zeolite is obtained by mixing zeolite with a particle size ≤100μm and zeolite with a particle size of 1.5-3mm at a mass ratio of 1:3-5.

[0006] Preferably, the potassium fulvic acid content in the potassium fulvic acid is ≥50%, and the K2O content is ≥10%.

[0007] Preferably, the specific preparation method of the fermented tobacco waste root material includes the following steps: S1-1. Dry the waste tobacco roots until the moisture content is ≤18%, then bake them at 60-75℃ for 15-20 minutes, then grind them into powder and pass them through a 20-mesh sieve to obtain waste tobacco root powder for later use. S1-2. Add 1-2 times the volume of clean water to the waste root powder of flue-cured tobacco, then inoculate with 0.2%-0.3% of the total mass of waste root powder of flue-cured tobacco with Penicillium, ferment for 24-48 hours, and then steam sterilize to obtain sterilized material for later use. S1-3. Inoculate 0.1%-0.2% of the total mass of waste tobacco root powder with Pichia pastoris into the sterilized material, maintain the moisture content at 80%-120%, ferment for 4-7 days, and then dry at 30-40℃ to obtain the fermented waste tobacco root material.

[0008] Preferably, the drying temperature in step S1-1 is 30-35℃.

[0009] Preferably, the steam sterilization temperature in step S1-2 is 121°C and the time is 15-20 min.

[0010] Preferably, the composted straw manure is prepared by mixing animal manure and plant straw in a mass ratio of 1-3:1, composting for 50-60 days, and then drying. During the composting period, the humidity is maintained between 60% and 70%, and the compost is turned over every 10-15 days.

[0011] Preferably, the specific preparation method of the modified diatomite includes the following steps: S2-1. Add diatomaceous earth to a 15% sulfuric acid solution and treat in a water bath at 55-65℃ for 1-2 hours. Then wash with clean water until neutral to obtain pretreated diatomaceous earth. S2-2. Dissolve lauryl glucoside in ethanol to prepare a lauryl glucoside ethanol solution with a concentration of 5%-15%. S2-3. Place the pretreated diatomaceous earth in 3-5 times its volume of lauryl glucoside ethanol solution, stir thoroughly, filter, and then dry at 30-40℃ to obtain modified diatomaceous earth.

[0012] Preferably, in steps S2-3, the stirring speed is 800-1200 r / min and the stirring time is 15-20 min.

[0013] The preparation method of the above-mentioned acid-adjusting and acid-stabilizing functional organic fertilizer for red soil includes the following steps: (1) Mix and grind lime, tobacco waste root fermentation material and modified diatomaceous earth through a 100-mesh sieve to obtain a premix for later use; (2) Mix the premixed material with potassium humate and well-rotted straw manure thoroughly, then add graded zeolite, adjust the moisture content to 80%-100%, continue to mix evenly, granulate, and then dry to obtain organic fertilizer.

[0014] Preferably, the drying method in step (2) is to dry at 55-65℃ until the moisture content is ≤12%.

[0015] This invention provides a functional organic fertilizer for red soil that adjusts and stabilizes acidity, and its preparation method. Compared with the prior art, its advantages are as follows: This invention addresses the problems of severe acidification, weak acid buffering, easy acid reversion, and low organic matter in southern red soil. It utilizes components such as lime, potassium humate, fermented tobacco waste roots, decomposed straw manure, modified diatomaceous earth, and graded zeolite to achieve rapid acid neutralization, long-term pH stabilization, enhanced acid buffering, and integrated carbon increase and soil improvement. Furthermore, it can effectively promote crop growth and further improve soil quality. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the CF experimental field before harvest in an embodiment of the present invention; Figure 2 This is a schematic diagram of the CK experimental field before harvest in an embodiment of the present invention; Figure 3 This is a schematic diagram of the OG experimental field before harvest in an embodiment of the present invention; Figure 4 This is a schematic diagram of the YO experimental field before harvest in an embodiment of the present invention; Figure 5 This is a schematic diagram of the OC experimental field before harvest in an embodiment of the present invention; Figure 6 This is a schematic diagram comparing mature maize plants of OG, YO, and OC in an embodiment of the present invention; Figure 7 This is a comparative schematic diagram of corn ears (three in each group) of CF, CK, OC, YO, and OG according to the present invention. Detailed Implementation

[0017] 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.

[0018] The Penicillium used below is Penicillium ochreae, purchased from Shanghai Xuanya Biotechnology Co., Ltd., and the Kluyveromyces yeast is ATCC64299 Kluyveromyces yeast, purchased from Wuhan Huanna Biotechnology Co., Ltd.

[0019] Example 1: I. Preparation of each raw material: 1. Preparation of fermentation material: 1.1 Fermentation Material A: (1) Dry the waste tobacco roots at 30°C until the moisture content is ≤18%, then bake them at 65°C for 20 minutes, and then grind them into powder and pass them through a 20-mesh sieve to obtain waste tobacco root powder; (2) Add twice the volume of clean water to the waste root powder of flue-cured tobacco, then inoculate with 0.2% of the total mass of the waste root powder of flue-cured tobacco with Penicillium, ferment for 40 hours, and then sterilize with steam at 121℃ for 20 minutes to obtain sterilized material for later use. (3) Inoculate 0.2% of the total mass of waste tobacco root powder with Kluyveromyces yeast into sterilized material, keep the moisture content at 80%-120%, ferment for 6 days, and then dry at 35℃ to obtain fermented material A.

[0020] 1.2 Fermentation Material B: The preparation method of fermentation material B is basically the same as that of fermentation material A, except for step (1). The specific operation of step (1) is as follows: dry the waste roots of flue-cured tobacco at 30°C and grind them into powder and pass them through a 20-mesh sieve to obtain pretreated waste root powder of flue-cured tobacco.

[0021] 1.3 Fermentation material C: The preparation method of fermentation material C is basically the same as that of fermentation material A. The difference is that the fermentation process of Penicillium is omitted. The specific steps are as follows: after step (1), the waste root powder of flue-cured tobacco is directly added to 2 times the volume of water, and then 0.2% of the total mass of waste root powder of flue-cured tobacco is inoculated with Kluyveromyces yeast for 6 days of fermentation treatment, and then dried at 35°C to obtain fermentation material C.

[0022] 2. Preparation of well-rotted straw manure: Mix sheep manure and corn stalks (crushed) at a mass ratio of 2:1 and compost for 60 days. During composting, maintain the humidity between 60% and 70%. Turn the pile over every 10-15 days. After composting, dry the pile to obtain well-rotted straw manure.

[0023] 3. Diatomaceous earth material: 3.1 Diatomaceous earth material A: Ordinary diatomaceous earth is not treated.

[0024] 3.2 Diatomaceous Earth Material B: (1) Add diatomaceous earth to a 15% sulfuric acid solution, treat with a 60°C water bath for 2 hours, and then wash with water until neutral to obtain pretreated diatomaceous earth; (2) Dissolve lauryl glucoside in ethanol to prepare a 10% lauryl glucoside ethanol solution; (3) Place the pretreated diatomite in 5 times the volume of lauryl glucoside ethanol solution, stir at 1000 r / min for 20 min, filter and dry at 35℃ to obtain diatomite material B.

[0025] 3.3 Diatomaceous earth material C: (1) Add diatomite to a 15% sulfuric acid solution, treat with a 60°C water bath for 2 hours, then wash with water until neutral, and dry at 35°C to obtain diatomite material C.

[0026] 4. Zeolite material: 4.1 Zeolite Material A: Zeolite particle size ≤ 100μm.

[0027] 4.2 Zeolite Material B: Zeolite particle size is 1.5-3mm.

[0028] 4.3 Zeolite C: Zeolite with a particle size ≤100μm and zeolite with a particle size of 1.5-3mm are mixed at a mass ratio of 1:4. 5. Lime: CaCO3 content ≥90%.

[0029] 6. Potassium humate: humic acid ≥ 50%, K2O ≥ 10%.

[0030] II. Preparation of different fertilizers: Prepare the ingredients according to the following weight proportions: 38 parts lime, 20 parts potassium humate, 11 parts fermented material, 22 parts decomposed straw manure, 8 parts diatomaceous earth, and 7 parts zeolite. The lime, fermentation material, and diatomaceous earth are mixed and ground through a 100-mesh sieve to obtain a premix for later use. The premixed material is mixed with potassium humate and well-rotted straw manure and stirred thoroughly. Then, zeolite is added, the moisture content is adjusted to 90%, and the mixture is stirred evenly again. After granulation, it is dried at 60℃ until the moisture content is ≤12% to obtain organic fertilizer.

[0031] Following the preparation method described above, different organic fertilizers can be prepared by selecting different raw materials, referring to Table 1 below: Table 1

[0032] III. Red Soil Acid Titration Experiment Red soil from the same region was collected, and impurities such as stones and plant residues were removed. After air drying, the soil was sieved through a 2mm sieve. The sieved soil was mixed with different organic fertilizers to prepare samples (the organic fertilizer content in the samples was set to 5%). Since lime is more effective in soil acidification, a lime control group and a blank control group were set up. The lime content in the samples of the lime control group was 5%, and the samples of the blank control group were pure sieved red soil.

[0033] 10g of sample was mixed with 25 mL of deionized water to prepare a soil suspension. 0.01mol / L HCl was used as the acid titrant and pH=3.5 was used as the acid titration endpoint. Each treatment group was repeated 3 times. By conducting acid titration experiments, the soil pH values ​​corresponding to different acid consumption volumes were recorded, and the acid buffer capacity (ABC) and acid neutralization capacity (ANC, which was neutralized by back titration using NaOH solution) were calculated. ABC reflects the soil's ability to resist changes in acidity, while ANC reflects the total amount of external acid neutralized by the soil. Both are core indicators for evaluating the effectiveness of alkaline amendment materials; the higher the value, the better the amendment effect.

[0034] The specific results are shown in Table 2 below: Table 2

[0035] The higher the ABC value, the stronger the soil's ability to resist pH decline and the better the long-term effectiveness of the amendment material. ANC reflects the total amount of external acid neutralized by the soil, directly reflecting the immediate acidification improvement effect of the amendment material. The higher the ANC value, the stronger the material's ability to neutralize soil acidity. Based on this, organic fertilizer groups with ABC ≥ 200 and ANC ≥ 60 were selected, namely experimental groups 1, 2, and 3, which can effectively improve the soil's buffering acidification capacity. In experimental groups 4-5, diatomaceous earth material A and diatomaceous earth material C will reduce the soil's buffering acidification capacity to a certain extent. At the same time, zeolite with a single particle size will also lead to a significant reduction in the soil's buffering acidification capacity, seriously affecting the effect of organic fertilizer.

[0036] IV. Crop Planting Experiment: Based on the above experiment, the organic fertilizers (i.e., organic fertilizer A, organic fertilizer B and organic fertilizer C) of experimental groups 1, 2 and 3 were selected as experimental fertilizers for field experiments. Organic fertilizers A, B and C were named OG, YO and OC respectively for the experiment. Five experimental plots of red soil were selected. Before the experiment, the soil pH of each plot was measured to be between 5.0 and 5.2. Three plots were then treated with OG, YO, and OC organic fertilizers as base fertilizer (60 kg / mu), respectively. The other two plots served as a conventional control group (CF) and a blank control group (CK). The blank control group received no fertilizer. The experimental control groups received a total of 60 kg / mu of compound fertilizer (N-P2O5-K2O: 20-7-7) and urea at a mass ratio of 5:1. Maize (Dunyu 810) was sown on April 20, 2025. Subsequently, 15 kg / mu of urea was applied as topdressing during the jointing stage and again during the tasseling stage.

[0037] Harvesting took place on September 30, 2025. The plant height (5 plants randomly selected, average value calculated), yield, and 100-kernel weight of maize in each experimental field were measured. Soil pH was also measured after planting. The specific results are shown in Table 3 below. Table 3

[0038] The specific experimental field conditions before corn planting and harvest are as follows: Figure 1-5 As shown, the maturity status of OG, YO, and OC maize plants is as follows. Figure 6 As shown, the harvested corn ears in each group are as follows: Figure 7 As shown in Table 3 above, applying conventional compound fertilizers and urea to the soil will exacerbate soil acidification. Without fertilizer application, the soil pH remains basically unchanged. Organic fertilizer A can effectively promote corn yield and increase the weight of 100 grains. On this basis, it can also effectively alleviate soil acidity and achieve partial soil restoration.

[0039] 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 functional organic fertilizer for regulating and stabilizing acidity in red soil, characterized in that, The organic fertilizer is composed of the following raw materials in parts by weight: 30-45 parts lime, 15-25 parts potassium humate, 10-12 parts fermented tobacco waste root material, 18-25 parts decomposed straw manure, 5-10 parts modified diatomite, and 5-8 parts graded zeolite. The fermented tobacco waste root material is prepared by roasting tobacco waste roots, grinding them into powder, inoculating with Penicillium mold for fermentation, sterilizing, then inoculating with Kluyveromyces yeast for further fermentation for 4-7 days, and then drying. The modified diatomaceous earth is prepared by acid washing of diatomaceous earth, mixing it thoroughly with an ethanol solution of lauryl glucoside, and then drying it. The graded particle size zeolite is obtained by mixing zeolite with a particle size ≤100μm and zeolite with a particle size of 1.5-3mm at a mass ratio of 1:3-5.

2. The organic fertilizer according to claim 1, characterized in that: The potassium fulvic acid content in the potassium fulvic acid is ≥50%, and the K2O content is ≥10%.

3. The organic fertilizer according to claim 1, characterized in that, The specific preparation method of the fermented waste tobacco root material includes the following steps: S1-1. Dry the waste tobacco roots until the moisture content is ≤18%, then bake them at 60-75℃ for 15-20 minutes, then grind them into powder and pass them through a 20-mesh sieve to obtain waste tobacco root powder for later use. S1-2. Add 1-2 times the volume of clean water to the waste root powder of flue-cured tobacco, then inoculate with 0.2%-0.3% of the total mass of waste root powder of flue-cured tobacco with Penicillium, ferment for 24-48 hours, and then steam sterilize to obtain sterilized material for later use. S1-3. Inoculate 0.1%-0.2% of the total mass of waste tobacco root powder with Pichia pastoris into the sterilized material, maintain the moisture content at 80%-120%, ferment for 4-7 days, and then dry at 30-40℃ to obtain the fermented waste tobacco root material.

4. The organic fertilizer according to claim 3, characterized in that: The drying temperature in step S1-1 is 30-35℃.

5. The organic fertilizer according to claim 3, characterized in that: In step S1-2, the steam sterilization temperature is 121℃ and the time is 15-20 minutes.

6. The organic fertilizer according to claim 1, characterized in that: The decomposed straw manure is prepared by mixing animal manure and plant straw in a mass ratio of 1-3:1, composting for 50-60 days, and then drying. During the composting period, the humidity is maintained between 60% and 70%, and the compost is turned over every 10-15 days.

7. The organic fertilizer according to claim 1, characterized in that, The specific preparation method of the modified diatomite includes the following steps: S2-1. Add diatomaceous earth to a 15% sulfuric acid solution and treat it in a water bath at 55-65℃ for 1-2 hours. Then wash it with water until it is neutral to obtain pretreated diatomaceous earth. S2-2. Dissolve lauryl glucoside in ethanol to prepare a lauryl glucoside ethanol solution with a concentration of 5%-15%. S2-3. Place the pretreated diatomaceous earth in 3-5 times its volume of lauryl glucoside ethanol solution, stir thoroughly, filter, and then dry at 30-40℃ to obtain modified diatomaceous earth.

8. The organic fertilizer according to claim 7, characterized in that, In steps S2-3, the stirring speed is 800-1200 r / min, and the stirring time is 15-20 min.

9. A method for preparing organic fertilizer as described in any one of claims 1-8, characterized in that, The preparation method includes the following steps: (1) Mix and grind lime, tobacco waste root fermentation material and modified diatomaceous earth through a 100-mesh sieve to obtain a premix for later use; (2) Mix the premixed material with potassium humate and well-rotted straw manure thoroughly, then add graded zeolite, adjust the moisture content to 80%-100%, continue to mix evenly, granulate, and then dry to obtain organic fertilizer.

10. The preparation method according to claim 9, characterized in that: In step (2), the drying method is to dry at 55-65℃ until the moisture content is ≤12%.

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