A composite soil amendment for acidic soils and method of application thereof

Abstract

The present application relates to the technical field of soil improvement, and particularly relates to a composite improver for acid soil and a method for applying the same, which comprises, by weight parts, 40-55 of natural mineral slow-release acid-regulating components, 20-35 of organic buffer components, 12-22 of mineral adsorption components, 4-8 of microbial activation components and 2-4 of auxiliary bonding components; the natural mineral slow-release acid-regulating components are composed of dolomite powder and modified limestone powder, and the modified limestone powder is prepared by high-temperature calcination activation; through multi-component synergistic compounding and specific preparation and application process, the present application realizes comprehensive long-acting improvement of acid soil, and solves the problems of single improvement effect, short-acting and insufficient activity in the prior art.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, specifically to a composite soil conditioner for acidic soils and its application method. Background Technology

[0002] Acidic soil is a common type of soil in arable land. Continuous soil acidification will cause a series of physical, chemical and ecological problems, which will directly affect crop growth and agricultural production. At present, acidic soil improvement mainly uses single acid-adjusting materials, which can only achieve short-term acid-base adjustment and cannot stabilize soil pH in the long term. The improvement effect is prone to rebound.

[0003] Existing soil conditioners generally suffer from the problem of single-component composition, lacking the synergistic configuration of organic buffers, mineral adsorption and microbial activation, making it difficult to simultaneously complete soil fertilization, heavy metal passivation and micro-ecological restoration; most conditioners do not activate and modify the raw materials, resulting in insufficient reactivity of the materials themselves and limited effect on the soil, failing to effectively improve soil compaction, poor porosity and other structural problems.

[0004] Existing soil amendment technologies are applied in a relatively crude manner, often using a single application method. This results in uneven mixing of materials with the soil, making it difficult to precisely control nutrient release and adapt to acidic soils of different textures and pollution levels. Furthermore, existing amendment schemes fail to address the multiple needs of acidification, fertilization, heavy metal fixation, and microbial activation, leading to a one-sided overall amendment effect that cannot meet the amendment requirements of different scenarios such as field production, facility cultivation, and mine reclamation. In addition, some amendment preparation processes do not consider the protection of component activity, which can easily cause the inactivation of functional components, further reducing the amendment effect. Summary of the Invention

[0005] The primary objective of this invention is to provide a composite soil conditioner for acidic soils and its application method.

[0006] A further objective of this invention is to provide a composite soil conditioner for acidic soils, characterized in that, by total weight, it comprises: 40-55 parts of a natural mineral slow-release acid-regulating component, 20-35 parts of an organic buffer component, 12-22 parts of a mineral adsorption component, 4-8 parts of a microbial activation component, and 2-4 parts of an auxiliary binder component; wherein the natural mineral slow-release acid-regulating component is composed of dolomite powder and modified limestone powder, the modified limestone powder being obtained by high-temperature calcination activation; the organic buffer component is composed of humic acid, fulvic acid, and seaweed extract; the mineral adsorption component is composed of modified zeolite and bentonite, the modified zeolite being obtained by soaking and modifying with dilute sulfuric acid and then drying; the microbial activation component is composed of Bacillus subtilis inoculant, Trichoderma inoculant, and trehalose; and the auxiliary binder component is composed of saponins and beeswax.

[0007] Preferably, in the natural mineral slow-release acid-adjusting component, dolomite powder accounts for 30-40 parts and modified limestone powder accounts for 10-15 parts.

[0008] Preferably, in the organic buffer component, humic acid comprises 12-20 parts, fulvic acid comprises 6-12 parts, and seaweed extract comprises 2-3 parts; in the mineral adsorption component, modified zeolite comprises 8-15 parts, and bentonite comprises 4-5.5 parts; in the microbial activation component, Bacillus subtilis inoculant comprises 2-5 parts, Trichoderma inoculant comprises 1-2 parts, and trehalose comprises 1 part; in the auxiliary binder component, saponins comprise 1-2 parts, and beeswax comprises 1-2 parts.

[0009] Preferably, the composite modifier is in granular form, with a particle size of 3mm-3.5mm and a particle moisture content of 3.5%-4%.

[0010] A method for preparing a composite soil conditioner for acidic soils includes the following steps: Dolomite powder was pulverized to 100 mesh, limestone powder to 80 mesh, zeolite to 120 mesh, bentonite to 100 mesh, humic acid and fulvic acid to 80 mesh, and seaweed extract to 100 mesh. The limestone powder was activated by high-temperature calcination, and the zeolite was modified by soaking in dilute sulfuric acid, rinsed until neutral, and dried. The pretreated raw materials were mixed by low-speed stirring, high-speed stirring, medium-speed stirring, and low-speed stirring in sequence. The mixture was extruded and granulated, and then dried at low temperature to obtain granular modifier.

[0011] Preferably, the limestone powder is calcined at a temperature of 500℃-650℃ for 2.5h-4h, and then naturally cooled to room temperature; the zeolite is soaked in a dilute sulfuric acid solution with a mass fraction of 4%-8% for 15h-24h, and then dried at 70℃ to a moisture content of 4%.

[0012] Preferably, the stirring speed is 250 r / min, 650 r / min, 450 r / min, and 250 r / min respectively; the stirring time is 20 min, 25 min-30 min, 30 min-35 min, and 18 min-20 min respectively; the stirring ambient temperature is constant at 28℃; and the low-temperature drying temperature is 50℃-52℃.

[0013] A method for applying a compound soil conditioner to acidic soils, wherein the total amount of compound soil conditioner applied is 1.4 t / hm. 2 -2.8t / hm 2 Apply the fertilizer using a layered rotary tillage method, and then apply it in stages after application. After the application, adjust the soil moisture content to 60%-70% of the maximum field capacity.

[0014] Preferably, the rotary tillage is applied in two layers. The first layer is 60%-70% of the total amount, with a tillage depth of 10cm-15cm; the second layer is 30%-40% of the total amount, with a tillage depth of 20cm-30cm.

[0015] Preferably, the phased application includes seedling stage application and application before flowering or jointing stage. The amount of seedling stage application is 10%-15% of the initial total application amount, and the amount of application before flowering or jointing stage application is 10%-15% of the initial total application amount.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention achieves comprehensive and long-term improvement of acidic soil through multi-component synergistic compounding and specific preparation and application processes, solving the problems of single, short-term, and insufficient activity of existing technologies. Furthermore, the combination of natural mineral slow-release acid-regulating components and organic buffer components can stably regulate soil pH and maintain a stable acid-base environment, avoiding adverse effects on soil and crops caused by drastic pH fluctuations. The mineral adsorption components can fix harmful ions in the soil, reduce their migration and transformation capacity, and reduce the risk of toxicity to crops.

[0017] 2. The microbial activation components of this invention can increase the number and activity of soil microorganisms, optimize the soil microecological structure, and promote the transformation and absorption of soil nutrients. After specific modification treatment, the raw materials of this invention have significantly improved reactivity, which can effectively improve soil structure, optimize soil porosity, and increase soil organic matter content. Moreover, the preparation process of segmented stirring and low-temperature drying can retain the activity of each functional component to the greatest extent and ensure the stability of the quality of the amendment.

[0018] 3. The layered rotary tillage and phased application method of this invention allows the soil conditioner to be evenly distributed in the soil tillage layer, achieving continuous and stable nutrient release, and adapting to the growth needs of different types of acidic soils and various crops. This invention integrates the functions of acidification, fertilization, passivation and activation, and the improvement effect is comprehensive and long-lasting, which can effectively improve soil fertility and tillage performance. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0020] All embodiments were conducted at the same standardized testing site, with a uniform testing area of ​​100m². 2 The field management conditions, such as water and fertilizer, light, and plant protection, were completely consistent, and the experimental period was uniformly 120 days.

[0021] Example 1: This embodiment is suitable for strongly acidic red soil and the suitable crop is soybean.

[0022] The composite modifier is composed of the following raw materials by weight: 45 parts of natural mineral slow-release acid-regulating component, consisting of 35 parts of dolomite powder and 10 parts of modified limestone powder; 25 parts of organic buffer component, consisting of 15 parts of humic acid, 8 parts of fulvic acid and 2 parts of seaweed extract; 15 parts of mineral adsorption component, consisting of 10 parts of modified zeolite and 5 parts of bentonite; 5 parts of microbial activation component, consisting of 3 parts of Bacillus subtilis inoculant, 1 part of Trichoderma inoculant and 1 part of trehalose; and 3 parts of auxiliary binder component, consisting of 1.5 parts of saponins and 1.5 parts of beeswax.

[0023] Modification process: Modified limestone powder is prepared by high-temperature calcination activation process, and modified zeolite is prepared by soaking in dilute sulfuric acid for modification and then drying.

[0024] Preparation methods: Dolomite powder is pulverized to 100 mesh, sieved to remove impurities, and set aside. Limestone powder is pulverized to 80 mesh, placed in a calcining furnace and calcined at 550℃ for 3 hours, then naturally cooled to room temperature to obtain modified limestone powder. Zeolite is pulverized to 120 mesh, placed in a 5% dilute sulfuric acid solution and soaked at room temperature for 18 hours, stirred every 4 hours. After soaking, it is repeatedly rinsed with water until neutral, and dried at 70℃ until the material moisture content is 4% to obtain modified zeolite. Bentonite is pulverized to 100 mesh and dried until the moisture content is 4% for use. Humic acid and fulvic acid are pulverized to 80 mesh and impurities are removed for use. Seaweed extract is pulverized to 100 mesh for use. Pretreated dolomite powder and modified limestone powder were added to a mixer and stirred at a low speed of 250 rpm for 20 minutes. Humic acid, fulvic acid, and seaweed extract were then added and stirred at a high speed of 650 rpm for 25 minutes. Modified zeolite and bentonite were then added and stirred at a medium speed of 450 rpm for 30 minutes. Finally, microbial activating components and auxiliary binder components were added and stirred at a low speed of 250 rpm for 18 minutes to obtain a homogeneous mixture. The mixture was fed into an extrusion granulator to produce granules with a diameter of 3 mm, controlling the initial material moisture content to 10%. The granules were then dried at 50°C until the moisture content reached 4%. After sieving to remove impurities, the granules were sealed in packaging with silica gel desiccant and stored in a cool, dry environment at 20°C.

[0025] Application method: The test soil was strongly acidic red soil with an initial pH of 4.2, an organic matter content of 1.1%, and a bulk density of 1.58 g / cm³. 3 The cadmium content was 0.32 mg / kg, and the aluminum content was 86 mg / kg. The total amount of compound amendment applied was 2.0 t / hm². 2 The application method is to use a layered rotary tillage method. The first layer is applied with 70% of the total amount and a rotary tillage depth of 12cm, and the second layer is applied with 30% of the total amount and a rotary tillage depth of 25cm.

[0026] Apply 12% of the initial total amount during the seedling stage and 12% of the initial total amount before the flowering stage. After each application, irrigate with clean water to bring the soil moisture content to 65% of the field capacity.

[0027] Example 2: This embodiment is suitable for strongly acidic red soil and is suitable for planting corn.

[0028] The composite modifier, by weight, comprises the following raw materials: 50 parts of natural mineral slow-release acid-regulating component, consisting of 38 parts dolomite powder and 12 parts modified limestone powder; 30 parts of organic buffer component, consisting of 18 parts humic acid, 10 parts fulvic acid, and 2 parts seaweed extract; 12 parts of mineral adsorption component, consisting of 8 parts modified zeolite and 4 parts bentonite; 6 parts of microbial activation component, consisting of 4 parts Bacillus subtilis inoculant, 1 part Trichoderma inoculant, and 1 part trehalose; and 2 parts of auxiliary binder component, consisting of 1 part saponin and 1 part beeswax. The raw material modification process is completely consistent with that of Example 1.

[0029] Preparation method: The overall process is the same as in Example 1, except that the high-speed stirring time after mixing the organic and mineral components is adjusted to 30 min.

[0030] Application method: The test soil type and initial physicochemical indicators were consistent with those of Example 1, but the crop planted was replaced with corn.

[0031] The total amount of compound amendment applied was 2.2 t / hm. 2 The layered application ratio and rotary tillage depth are consistent with those in Example 1.

[0032] The amount of supplementary application in stages is adjusted to 15% during the seedling stage and 15% before flowering. Before flowering, the frequency of watering should be increased appropriately to stabilize the soil moisture content in the range of 65% to 70%.

[0033] Example 3: This embodiment is suitable for strongly acidic red soil with high heavy metal content, and the suitable crop is soybean.

[0034] The composite modifier is composed of the following raw materials by weight: 50 parts of natural mineral slow-release acid-regulating component, consisting of 38 parts of dolomite powder and 12 parts of modified limestone powder; 30 parts of organic buffer component, consisting of 18 parts of humic acid, 10 parts of fulvic acid and 2 parts of seaweed extract; 18 parts of mineral adsorption component, consisting of 14 parts of modified zeolite and 4 parts of bentonite; 6 parts of microbial activation component, consisting of 4 parts of Bacillus subtilis inoculant, 1 part of Trichoderma inoculant and 1 part of trehalose; and 2 parts of auxiliary binder component, consisting of 1 part of saponin and 1 part of beeswax.

[0035] Modification process: The modified zeolite was soaked in a 7% dilute sulfuric acid solution for 22 hours, with stirring every 3 hours. The modification process for the remaining raw materials was the same as in Example 1.

[0036] Preparation method: The overall process is basically the same as in Example 1, except that the pretreatment and mixing parameters of the mineral adsorption components are adjusted accordingly, and the stirring time of the mineral adsorption components at medium speed is extended to 35 min.

[0037] Application method: The test soil was a highly acidic red soil with excessive heavy metals, an initial soil pH of 4.1, an organic matter content of 1.0%, and a soil bulk density of 1.60 g / cm³. 3 The cadmium content is 0.38 mg / kg, and the aluminum content is 92 mg / kg.

[0038] The layered application ratio is the same as in Example 2. The depth of the second layer of rotary tillage is adjusted to 30cm. An additional 25% of the initial total application amount is applied after the crop is harvested.

[0039] Example 4: This embodiment is suitable for strongly acidic red soil with high heavy metal content, suitable for planting corn, and suitable for large-scale field production scenarios.

[0040] The raw material ratio of the composite modifier is completely consistent with that of Example 3. The specific components by weight are as follows: 50 parts of natural mineral slow-release acid-regulating component, composed of 38 parts dolomite powder and 12 parts modified limestone powder; 30 parts of organic buffer component, composed of 18 parts humic acid, 10 parts fulvic acid, and 2 parts seaweed extract; 18 parts of mineral adsorption component, composed of 14 parts modified zeolite and 4 parts bentonite; 6 parts of microbial activation component, composed of 4 parts Bacillus subtilis inoculant, 1 part Trichoderma inoculant, and 1 part trehalose; and 2 parts of auxiliary binder component, composed of 1 part saponin and 1 part beeswax. The raw material modification process is completely consistent with that of Example 3.

[0041] Preparation method: Based on the process in Example 3, the parameters were optimized. The calcination temperature of the modified limestone powder was adjusted to 600℃ and the calcination time was adjusted to 2.5h. After the addition of the microbial activation component, the low-speed stirring time was extended to 20min and the stirring environment temperature was kept constant at 28℃. The granulation particle size was adjusted to 3.5mm and the material drying temperature was adjusted to 52℃. Finally, the material was dried to a moisture content of 3.5%.

[0042] Application method: The soil type and initial physicochemical properties were the same as in Example 3. The crop planted was maize, and the total amount of compound soil conditioner applied was 2.2 t / hm. 2 The remaining application parameters and supplementary application plan are completely consistent with those in Example 3.

[0043] Example 5: This embodiment is suitable for sandy, strongly acidic soil, and the suitable crop is soybean.

[0044] The raw material ratio of the composite modifier is completely consistent with that of Example 4. The specific components by weight are as follows: 50 parts of natural mineral slow-release acid-regulating component, composed of 38 parts dolomite powder and 12 parts modified limestone powder; 30 parts of organic buffer component, composed of 18 parts humic acid, 10 parts fulvic acid, and 2 parts seaweed extract; 18 parts of mineral adsorption component, composed of 14 parts modified zeolite and 4 parts bentonite; 6 parts of microbial activation component, composed of 4 parts Bacillus subtilis inoculant, 1 part Trichoderma inoculant, and 1 part trehalose; and 2 parts of auxiliary binder component, composed of 1 part saponin and 1 part beeswax. The raw material modification process and overall preparation method are completely consistent with Example 4.

[0045] Application method: The test soil was sandy, strongly acidic red soil with an initial pH of 4.3, an organic matter content of 0.9%, and a bulk density of 1.62 g / cm³. 3 The cadmium content is 0.30 mg / kg, and the aluminum content is 88 mg / kg.

[0046] The total amount of compound amendment applied was 2.3 t / hm. 2 The application ratio for the first layer is adjusted to 65% and the second layer to 35%.

[0047] The phased application plan has been adjusted to apply 10% during the seedling stage and 15% before flowering. During the application, a 0.5% seaweed extract diluted solution will be sprayed simultaneously, and after application, the soil will be covered with 5cm of straw to retain moisture.

[0048] Example 6: This embodiment is suitable for acidic soil in mine reclamation, and the suitable crop is soybean.

[0049] The composite modifier is composed of the following raw materials by weight: 55 parts of natural mineral slow-release acid-adjusting component, consisting of 40 parts of dolomite powder and 15 parts of modified limestone powder; 35 parts of organic buffer component, consisting of 20 parts of humic acid, 12 parts of fulvic acid and 3 parts of seaweed extract; 20 parts of mineral adsorption component, consisting of 15 parts of modified zeolite and 5 parts of bentonite; 8 parts of microbial activation component, consisting of 5 parts of Bacillus subtilis inoculant, 2 parts of Trichoderma inoculant and 1 part of trehalose; and 4 parts of auxiliary binder component, consisting of 2 parts of saponins and 2 parts of beeswax.

[0050] Modification process: Modified zeolite was soaked in 8% dilute sulfuric acid solution for 24 hours, and modified limestone powder was calcined at 650℃ for 4 hours. The rest of the pretreatment process was the same.

[0051] Preparation method: The overall process is basically the same as in Example 4, except that the soaking time of zeolite and the calcination parameters of limestone powder are adjusted accordingly.

[0052] Application method: The test soil was acidic soil from a reclaimed mine, with an initial pH of 4.0, organic matter content of 0.8%, and bulk density of 1.65 g / cm³.3 The cadmium content is 0.42 mg / kg, and the aluminum content is 95 mg / kg.

[0053] The total amount of compound amendment applied was 2.8 t / hm. 2 The application ratio for the first layer is 60% and the second layer is 40%, corresponding to rotary tillage depths of 15cm and 30cm, respectively.

[0054] Apply the fertilizer in stages: 15% during the seedling stage, 15% before flowering, and 25% after crop harvest. After application, cover with 8cm of straw to retain moisture and water until the soil moisture content reaches 70% of the field capacity.

[0055] Example 7: This embodiment is suitable for conventional slightly acidic soil and is suitable for planting wheat.

[0056] The composite modifier is composed of the following raw materials by weight: 40 parts of natural mineral slow-release acid-regulating component, consisting of 30 parts of dolomite powder and 10 parts of modified limestone powder; 20 parts of organic buffer component, consisting of 12 parts of humic acid, 6 parts of fulvic acid and 2 parts of seaweed extract; 20 parts of mineral adsorption component, consisting of 15 parts of modified zeolite and 5 parts of bentonite; 4 parts of microbial activation component, consisting of 2 parts of Bacillus subtilis inoculant, 1 part of Trichoderma inoculant and 1 part of trehalose; and 2 parts of auxiliary binder component, consisting of 1 part of saponin and 1 part of beeswax.

[0057] Modification process: The modified zeolite was soaked in a 4% dilute sulfuric acid solution for 15 hours, and the modified limestone powder was calcined at a constant temperature of 500℃ for 2.5 hours.

[0058] Preparation method: The overall process is basically the same as in Example 4, and the raw material modification parameters can be adjusted accordingly.

[0059] Application method: The test soil was a slightly acidic red soil with an initial pH of 5.8, an organic matter content of 1.5%, and a bulk density of 1.45 g / cm³. 3 The cadmium content is 0.20 mg / kg, and the aluminum content is 65 mg / kg.

[0060] The total amount of compound amendment applied was 1.5 t / hm. 2 The application ratios in the layers are 65% and 35%, and the rotary tillage depths are 12cm and 25cm, respectively.

[0061] Apply the fertilizer in stages: 10% during the seedling stage, 10% before flowering, and 20% after crop harvest. After application, water the soil until the soil moisture content reaches 65% of the field capacity.

[0062] Example 8: This embodiment is suitable for clayey, slightly acidic soil, and the suitable crop is wheat.

[0063] The composite modifier is composed of the following raw materials by weight: 40 parts of natural mineral slow-release acid-regulating component, consisting of 30 parts of dolomite powder and 10 parts of modified limestone powder; 20 parts of organic buffer component, consisting of 12 parts of humic acid, 6 parts of fulvic acid and 2 parts of seaweed extract; 22 parts of mineral adsorption component, consisting of 16.5 parts of modified zeolite and 5.5 parts of bentonite; 4 parts of microbial activation component, consisting of 2 parts of Bacillus subtilis inoculant, 1 part of Trichoderma inoculant and 1 part of trehalose; and 2 parts of auxiliary binder component, consisting of 1 part of saponin and 1 part of beeswax.

[0064] Modification process: The modified zeolite was soaked in a 5% dilute sulfuric acid solution for 18 hours, and stirred once every 4 hours. The remaining modification process was the same as in Example 7.

[0065] Preparation method: Based on the process in Example 7, the stirring time of the mineral adsorption component at medium speed was extended to 30 min, while the other process parameters remained unchanged.

[0066] Application method: The test soil was a clayey, slightly acidic soil with an initial pH of 5.7, an organic matter content of 1.6%, and a bulk density of 1.50 g / cm³. 3 The cadmium content is 0.18 mg / kg, and the aluminum content is 62 mg / kg.

[0067] The total amount of compound amendment applied was 1.4 t / hm. 2 The application ratios were 70% and 30% in layers, with rotary tillage depths of 10cm and 20cm, respectively.

[0068] Apply the fertilizer in stages: 10% during the seedling stage and 10% before flowering. After application, water the soil until the soil moisture content reaches 60% of the field capacity.

[0069] Example 9: This embodiment is suitable for cultivating acidified soil in facilities, and the suitable crops are vegetables.

[0070] The composite modifier is composed of the following raw materials by weight: 40 parts of natural mineral slow-release acid-regulating component, consisting of 30 parts of dolomite powder and 10 parts of modified limestone powder; 25 parts of organic buffer component, consisting of 15 parts of humic acid, 8 parts of fulvic acid and 2 parts of seaweed extract; 20 parts of mineral adsorption component, consisting of 15 parts of modified zeolite and 5 parts of bentonite; 6 parts of microbial activation component, consisting of 3.5 parts of Bacillus subtilis inoculant, 1.5 parts of Trichoderma inoculant and 1 part of trehalose; and 2 parts of auxiliary binding component, consisting of 1 part of saponin and 1 part of beeswax.

[0071] Modification process: The modified zeolite was soaked in a 6% dilute sulfuric acid solution for 16 hours, and the remaining modification process was the same as in Example 7.

[0072] Preparation method: Based on the process in Example 7, the ambient temperature was kept constant at 28°C during the addition of the microbial activation component, while the other process parameters remained unchanged.

[0073] Application method: The test soil was acidified soil from greenhouse cultivation, with an initial pH of 5.6, organic matter content of 1.4%, and bulk density of 1.48 g / cm³. 3 The cadmium content is 0.22 mg / kg, and the aluminum content is 68 mg / kg.

[0074] The total amount of compound amendment applied was 1.8 t / hm. 2 The application ratios in the layers are 65% and 35%, and the rotary tillage depths are 12cm and 25cm, respectively.

[0075] Apply the fertilizer in stages: 12% during the seedling stage and 12% before flowering. After application, regulate the humidity inside the greenhouse to maintain a suitable environment for crop growth.

[0076] Example 10: This embodiment is suitable for acidic paddy soil and is suitable for planting rice.

[0077] The composite modifier, by weight, comprises the following raw materials: 40 parts of natural mineral slow-release acid-regulating component, consisting of 30 parts dolomite powder and 10 parts modified limestone powder; 30 parts of organic buffer component, consisting of 18 parts humic acid, 10 parts fulvic acid, and 2 parts seaweed extract; 20 parts of mineral adsorption component, consisting of 15 parts modified zeolite and 5 parts bentonite; 4 parts of microbial activation component, consisting of 2 parts Bacillus subtilis inoculant, 1 part Trichoderma inoculant, and 1 part trehalose; and 2 parts of auxiliary binder component, consisting of 1 part saponin and 1 part beeswax. The modification process and preparation method are completely consistent with those in Example 7.

[0078] Application method: The test soil was acidic paddy soil with an initial pH of 5.5, an organic matter content of 1.7%, and a bulk density of 1.42 g / cm³. 3 The cadmium content was 0.19 mg / kg, and the aluminum content was 60 mg / kg. The total amount of compound amendment applied was 1.8 t / hm. 2 The application ratios in the layers are 60% and 40%, and the rotary tillage depths are 10cm and 20cm, respectively.

[0079] Apply the fertilizer in stages: 10% during the seedling stage and 15% during the jointing stage, combined with irrigation operations in paddy fields, to stabilize the soil moisture content at 70%.

[0080] Comparative Example 1: This comparative example retains only the acid-adjusting and binding base components. The composite modifier consists of 45 parts of natural mineral slow-release acid-adjusting components and 3 parts of auxiliary binding components. The natural mineral slow-release acid-adjusting components consist of 35 parts of dolomite powder and 10 parts of modified limestone powder, completely removing organic buffer components, mineral adsorption components, and microbial activation components.

[0081] The methods for raw material pretreatment, mixing and preparation, granulation and drying, and field application are completely consistent with those in Example 1.

[0082] Comparative Example 2: This comparative study retains four types of components: mineral acidification, organic buffer, mineral adsorption, and auxiliary binder, while removing all microbial activation components. At the same time, all raw materials are used directly without any modification or activation pretreatment.

[0083] The proportions of each group, material mixing, granulation and drying, and field application processes are completely consistent with those in Example 1.

[0084] Comparative Example 3: The proportions of each component in this comparative study are adjusted differently. The composite modifier, by weight, consists of 55 parts of natural mineral slow-release acid-regulating component, 10 parts of organic buffer component, 22 parts of mineral adsorption component, 2 parts of microbial activation component, and 5 parts of auxiliary binder component. The proportions of each component deviate from the optimal ratio range of this invention.

[0085] The preparation process and application method are completely consistent with those in Example 1.

[0086] Comparative Example 4: The raw material ratios in this comparative example are completely consistent with those in Example 1. The raw material modification process is simplified by eliminating the high-temperature calcination of limestone powder and the modification of zeolite with dilute sulfuric acid. All raw materials are directly crushed and mixed for granulation. The drying temperature is uniformly adjusted to 70°C. The remaining preparation process and field application methods are completely consistent with those in Example 1.

[0087] Comparative Example 5: The raw material ratio and complete preparation process of this comparative example are completely consistent with those of Example 1. The field application method is simplified, the layered rotary tillage and phased application process are eliminated, the soil conditioner is evenly spread on the soil surface in one go, and the soil is uniformly rotary tilled to 15cm. No subsequent application or watering is carried out throughout the process.

[0088] Comparative Example 6: The raw material ratio, preparation process, and application method of this comparative example are basically the same as those of Example 1, except that the trehalose component in the microbial activation component is removed, while the Bacillus subtilis inoculant and Trichoderma inoculant are retained.

[0089] Comparative Example 7: This comparative model retains the acid-adjusting, microbial activation, and binding base components. The composite modifier consists of 45 parts of natural mineral slow-release acid-adjusting components, 5 parts of microbial activation components, and 3 parts of auxiliary binding components, completely removing organic buffer components and mineral adsorption components.

[0090] The preparation process and field application method are completely consistent with those in Example 1.

[0091] All weight parts mentioned in this invention refer to total weight parts, and the weight parts within each composite component refer to the internal weight parts ratio of that composite component.

[0092] The viable count of Bacillus subtilis inoculant used in this invention is 5.0 × 10⁻⁶. 9 CFU / g - 1.0 × 10¹⁰ CFU / g, Trichoderma viable count is 2.0 × 10¹⁰ 9 CFU / g - 5.0 × 10 9 CFU / g; saponins are food grade with a purity ≥90%; beeswax is natural beeswax with a melting point of 62℃-67℃.

[0093] During the preparation process, natural mineral slow-release acid-adjusting components are added during the low-speed stirring stage, organic buffer components are added during the high-speed stirring stage, mineral adsorption components are added during the medium-speed stirring stage, and microbial activation components and auxiliary binder components are added during the low-speed stirring stage.

[0094] The reactivity of modified limestone powder is enhanced after high-temperature calcination and activation. The adsorption sites of modified zeolite are increased after soaking in dilute sulfuric acid. The segmented stirring and low-temperature drying process can retain the activity of each component. Layered rotary tillage and phased application can make the soil conditioner evenly distributed in the soil tillage layer.

[0095] Performance testing and results analysis: The total performance test period was 120 days. Various soil and crop indicators were tested at 30, 60 and 120 days after the application of the amendment. All testing procedures, equipment and judgment standards strictly followed the national agricultural industry standards. Five random sampling points were set up in each test area. All indicators were tested three times and the average value was taken as the final test result. The specific test indicators and testing methods are as follows.

[0096] Soil pH was measured using the potentiometric method, in accordance with the standard NY / T1121.2-2006. The water-to-soil volume ratio was set to 2.5:1. After magnetic stirring for 2 minutes, the soil was allowed to stand for 30 minutes before measurement.

[0097] Soil bulk density was measured using the ring sampler method, with the sampling depth controlled between 20cm and 30cm, to characterize the degree of soil looseness and the effect of structural improvement.

[0098] Soil organic matter content was determined using the potassium dichromate oxidation external heating method, reflecting the effect of soil fertility improvement.

[0099] Cadmium and lead in soil heavy metal indicators were determined by graphite furnace atomic absorption spectrophotometry, while aluminum was determined by inductively coupled plasma atomic emission spectrometry, to evaluate the passivation effect of soil heavy metals.

[0100] Soil microbial abundance was determined using the plate count method to detect the number of viable Bacillus subtilis and Trichoderma in the soil.

[0101] Crop yield was converted to yield per hectare based on the actual measured yield in the experimental area, reflecting the yield-increasing effect of the amendment.

[0102] The test results are shown in Tables 1, 2, and 3 below: Table 1: ; Table 2: ; Table 3: ; Results analysis: The test data from the examples and comparative examples show that the formulation, raw material modification process, preparation parameters and application method of the acidic soil composite amendment of the present invention have a synergistic effect and none of them can be omitted. The comparative examples, due to the lack of core components, simplified processes or changes in application methods, cannot achieve the improvement effect of the examples.

[0103] Comparative Example 1, by removing the organic buffer, mineral adsorption, and microbial activation components and retaining only the mineral acidification and auxiliary binding components, showed a significantly reduced increase in soil pH, a slow decrease in soil bulk density, no significant increase in organic matter content, poor heavy metal passivation, and, due to the absence of microbial components, zero soil microbial abundance. Crop yield decreased by 31.25% compared to Example 1, demonstrating that multi-component synergy is the core of achieving soil acidification, fertilization, passivation, and activation. Comparative Example 7, by removing the organic buffer and mineral adsorption components, also exhibited insufficient heavy metal passivation and poor soil structure improvement, further verifying the necessity of organic buffer and mineral adsorption components in enhancing soil fertility and fixing heavy metal ions.

[0104] Comparative Example 2 did not modify or activate the raw materials and removed the microbial activation components, resulting in insufficient raw material reactivity, slow acidification rate, low heavy metal passivation efficiency, and lack of soil microbial abundance. All indicators were inferior to those of Example 1. Comparative Example 4 eliminated the limestone powder calcination and zeolite dilute sulfuric acid modification processes and increased the drying temperature, leading to the loss of the activation effect of mineral components and the inactivation of microbial agents. The soil pH increase, microbial survival, and crop yield increase effects all decreased significantly. This fully demonstrates that the raw material modification process and mild preparation parameters can ensure the activity of each component of the amendment, which is the key to achieving long-term amendment.

[0105] Comparative Example 3 deviated from the optimal ratio of the present invention, and the proportions of each component were unbalanced. The effects of acidification, fertilization and passivation could not be synergistically exerted. The improvement of soil physicochemical indicators and crop yield were weaker than those of Example 1, which confirms that the component ratio defined by the present invention is the optimal range for achieving the best improvement effect.

[0106] Comparative Example 5 adopted a simplified application method of one-time broadcasting, non-layered rotary tillage, and phased application. The soil amendment was unevenly mixed with the soil, the nutrient release was out of control, the soil pH could not be maintained stably, and the improvement effect on indicators such as bulk density and organic matter was extremely poor. The crop yield dropped to the lowest among all groups. This shows that the application method of layered rotary tillage and phased application can ensure the uniform distribution and continuous effect of the amendment, which is an important guarantee for giving full play to the performance of the amendment.

[0107] In Comparative Example 6, trehalose was removed from the microbial activation component, resulting in a significant reduction in the number of surviving microorganisms and a weakened effect on soil microecological improvement. The various indicators were slightly inferior to those in Example 1, indicating that trehalose can effectively protect the activity of microbial agents and plays an auxiliary role in maintaining soil microbial abundance and improving the improvement effect.

[0108] In summary, this invention, through the organic combination of specific component ratios, raw material modification and activation, precise preparation processes, and scientific application methods, can achieve comprehensive effects such as pH stabilization in acidic soils, soil structure optimization, organic matter enhancement, heavy metal passivation, and increased crop yield.

[0109] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A composite soil conditioner for acidic soils, characterized in that, The product comprises, by total weight, 40-55 parts of natural mineral slow-release acid-regulating component, 20-35 parts of organic buffer component, 12-22 parts of mineral adsorption component, 4-8 parts of microbial activation component, and 2-4 parts of auxiliary binder component; the natural mineral slow-release acid-regulating component is composed of dolomite powder and modified limestone powder, the modified limestone powder being obtained by high-temperature calcination activation; the organic buffer component is composed of humic acid, fulvic acid, and seaweed extract; the mineral adsorption component is composed of modified zeolite and bentonite, the modified zeolite being obtained by soaking and modifying with dilute sulfuric acid and then drying; the microbial activation component is composed of Bacillus subtilis inoculant, Trichoderma inoculant, and trehalose; and the auxiliary binder component is composed of saponins and beeswax.

2. The composite modifier according to claim 1, characterized in that, In the natural mineral slow-release acid-adjusting component, dolomite powder accounts for 30-40 parts, and modified limestone powder accounts for 10-15 parts.

3. The composite modifier according to claim 1, characterized in that, In the organic buffering component, humic acid accounts for 12-20 parts, fulvic acid for 6-12 parts, and seaweed extract for 2-3 parts; in the mineral adsorption component, modified zeolite accounts for 8-15 parts, and bentonite for 4-5.5 parts; in the microbial activation component, Bacillus subtilis inoculant accounts for 2-5 parts, Trichoderma inoculant accounts for 1-2 parts, and trehalose accounts for 1 part. The auxiliary binder components consist of 1-2 parts saponins and 1-2 parts beeswax.

4. The composite modifier according to claim 1, characterized in that, The composite modifier is in granular form with a particle size of 3mm-3.5mm and a moisture content of 3.5%-4%.

5. A method for preparing a composite soil conditioner for acidic soils, used to prepare the composite soil conditioner according to any one of claims 1-4, characterized in that, Includes the following steps: Dolomite powder was pulverized to 100 mesh, limestone powder to 80 mesh, zeolite to 120 mesh, bentonite to 100 mesh, humic acid and fulvic acid to 80 mesh, and seaweed extract to 100 mesh. The limestone powder was activated by high-temperature calcination, and the zeolite was modified by soaking in dilute sulfuric acid, rinsed until neutral, and dried. The pretreated raw materials were mixed by low-speed stirring, high-speed stirring, medium-speed stirring, and low-speed stirring in sequence. The mixture was extruded and granulated, and then dried at low temperature to obtain granular modifier.

6. The preparation method according to claim 5, characterized in that, The limestone powder is calcined at a temperature of 500℃-650℃ for 2.5h-4h, and then naturally cooled to room temperature. The zeolite is soaked in a 4%-8% dilute sulfuric acid solution for 15h-24h, and then dried at 70℃ until the moisture content is 4%.

7. The preparation method according to claim 5, characterized in that, The stirring speeds were 250 r / min, 650 r / min, 450 r / min, and 250 r / min, respectively; the stirring times were 20 min, 25 min-30 min, 30 min-35 min, and 18 min-20 min, respectively; the stirring ambient temperature was kept constant at 28℃; and the low-temperature drying temperature was 50℃-52℃.

8. A method for applying a composite soil conditioner to acidic soils, using the composite soil conditioner according to any one of claims 1-4, characterized in that, The total amount of compound amendment applied was 1.4 t / hm. 2 -2.8t / hm 2 Apply the fertilizer using a layered rotary tillage method, and then apply it in stages after application. After the application, adjust the soil moisture content to 60%-70% of the maximum field capacity.

9. The application method according to claim 8, characterized in that, Layered rotary tillage is applied in two layers. The first layer applies 60%-70% of the total amount, with a tillage depth of 10cm-15cm. The second layer applies 30%-40% of the total amount, with a tillage depth of 20cm-30cm.

10. The application method according to claim 8, characterized in that, According to the application method of claim 8, the staged application includes seedling stage application and application before flowering or jointing stage, the amount of seedling stage application is 10%-15% of the initial total application amount, and the amount of application before flowering or jointing stage application is 10%-15% of the initial total application amount.