An acid-resisting and board-breaking high-activity super-micro composite mineral conditioner as well as a preparation method and application thereof

Abstract

The application discloses an acid-resisting and hardening-breaking high-activity super-micro composite mineral conditioner and a preparation method and application thereof, and relates to the technical field of soil improvement. The preparation method comprises the following steps: super-micro processing of magnesium oxide, calcium silicate, phosphate rock powder and shell powder respectively, mechanical force chemical reaction of the magnesium oxide and the calcium silicate to generate Mg-Si-Ca compound, mechanical force chemical reaction of the phosphate rock powder, nano silicon dioxide and potassium hydroxide to be converted into P-Si-K compound, and finally, mixing of the Mg-Si-Ca compound, the P-Si-K compound and the super-micro shell powder in a high-speed stirrer to prepare the acid-resisting and hardening-breaking high-activity super-micro composite mineral conditioner. The prepared acid-resisting and hardening-breaking high-activity super-micro composite mineral conditioner can neutralize acid consumption, produce gas to increase pore and break hardening, supplement calcium, magnesium, phosphorus and silicon nutrients, fix soil heavy metals and inhibit soil desiliconization and aluminum enrichment, so that the acid-resisting and hardening-breaking and soil nutrient improvement can be synergistically improved.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, and in particular to an acid-resistant, plate-breaking, highly active ultra-micro composite mineral conditioner, its preparation method, and its application. Background Technology

[0002] Against the backdrop of global food production facing arable land shortages and high inputs of fertilizers and pesticides, soil acidification and compaction are common soil quality degradation problems in current agricultural production. Long-term excessive application of fertilizers and continuous cropping practices lead to the concentration of free H+ in the soil solution. + Increased levels of heavy metals disrupt soil aggregate structure, leading to soil compaction and poor aeration. Simultaneously, soil acidification exacerbates the activation of heavy metal ions and the process of soil desilication and aluminum enrichment, reducing the availability of essential nutrients for crops such as calcium, magnesium, phosphorus, and silicon. This, in turn, affects crop root growth and nutrient absorption, resulting in a decline in agricultural yield and quality, and has become a significant factor restricting sustainable agricultural development.

[0003] pH improvement can independently increase soil organic carbon storage by 18%–20%, mineral-bound organic carbon (MAOC) by 11%–15%, and microbial residual carbon (MNC) by 12%–19%. pH optimization also improves clay colloid flocculation and particle cementation, significantly enhancing aggregate stability and encapsulating carbon within the pores of micro-aggregates, thus isolating it from microbial and enzymatic decomposition. This process is jointly dominated by pH-driven changes in microbial biomass and enhanced aggregate stability. By strengthening both physical and mineral protection according to local conditions, this approach provides a quantifiable pathway for the construction of sustainable carbon sinks in farmland.

[0004] Existing technologies often use alkaline mineral materials such as quicklime, hydrated lime, and calcium carbonate as soil conditioners. These conditioners neutralize soil acidity through acid-base reactions, and some are combined with silicate and phosphate components to replenish soil nutrients. However, traditional soil conditioners generally suffer from insufficient raw material fineness and low component activity. Conventionally ground mineral particles are relatively large, limiting their contact area with acidic soil components, resulting in low acid-base neutralization efficiency and difficulty in fully binding with soil particles, thus failing to effectively improve soil aggregate structure. Furthermore, traditional conditioners only neutralize acidity or replenish nutrients, making it difficult to simultaneously achieve the comprehensive effects of acid depletion, soil loosening and breaking up compaction, enhancing nutrient activity, and inhibiting soil desilication and aluminum enrichment.

[0005] In addition, existing soil conditioner preparation processes mostly employ simple physical mixing methods, with each component only surface-bonded and failing to form a stable composite structure. These components are easily lost with water in the soil and have a short duration of action. Some preparation processes use chemical modification methods to enhance the activity of the components, which introduces additional chemical reagents, posing a risk of secondary pollution. Furthermore, these processes have high energy consumption and do not meet the sustainable development requirements of green agriculture.

[0006] Therefore, ultramicrotechnology and micro / nanomaterials offer new opportunities to address these challenges. Combining advanced techniques such as electron microscopy, transmission electron microscopy, and X-ray CT tomography, while introducing pore structure analysis to reveal the characteristics of soil microstructure under root action, is crucial. Developing a comprehensive, highly active ultramicro composite mineral soil conditioner that combines high specific surface area, efficient acid consumption, soil loosening and breaking up compacted soil, nutrient activation, inhibition of soil degradation, and disease and stress resistance, while meeting the requirements of green environmental protection, energy saving, and high efficiency in its preparation process, and achieving the activation and stable composite of mineral components through physical processing to form micro-aggregates, has become a pressing technical challenge in the field of soil improvement. Summary of the Invention

[0007] Lime is a traditional acidic soil conditioner. While it can increase pH and reduce active aluminum, it cannot fix or passivate aluminum ions. When leached by heavy rain, aluminum ions are reactivated, still harming roots. Its effectiveness is limited in strongly acidic soils with high aluminum toxicity. It induces the fixation of nutrients such as phosphorus, magnesium, boron, and zinc, resulting in short-lived improvement, easy re-acidification, soil compaction, structural damage, and easy over-application leading to alkali damage. Uneven application can cause localized excessive alkalinity and fails to improve soil organic matter and fertility. The purpose of this invention is to overcome the technical shortcomings of existing and traditional soil conditioners, such as low component activity, limited soil improvement function, pollution-prone and energy-intensive preparation processes, and poor improvement effects. This invention provides an acid-inhibiting, plate-breaking, highly active ultrafine composite mineral powder conditioner, its preparation method, and its application. Since pores and aggregates are not mutually exclusive but rather "two sides of the same coin" in soil structure... Pores are the "stage" where processes occur, dominating short-term reaction rates; aggregates are the "products" of these processes, recording the history of soil evolution. Organic matter is the "actor," and microorganisms are the "director." The energy required to bind basic soil particles and micro-aggregates is several orders of magnitude higher than that required to cement large aggregates, addressing the most critical agricultural production issues at the "pore-aggregate-organic matter" level. Optimization of pore structure depends on the stable existence of aggregates, while the formation of aggregates, in turn, reshapes the pore network. Organic matter maintains the stability and diversity of aggregates through cementation. This invention aims to achieve the goals of improving soil quality, enhancing crop nutrient absorption efficiency, and increasing agricultural yield and quality through a green, all-physical preparation method, avoiding the introduction of chemical reagents, reducing production energy consumption and environmental pollution, improving the reaction efficiency of conditioners with soil acidic components and nutrient availability, extending the soil improvement cycle, and ultimately providing an efficient and environmentally friendly soil improvement solution for healthy soil and sustainable green agriculture.

[0008] To achieve the above objectives, in a first aspect, the present invention provides an acid-resistant, plate-breaking, highly active ultra-micro composite mineral conditioner, comprising magnesium oxide, natural calcium silicate, phosphate rock powder, nano-silica, potassium hydroxide, and shell powder.

[0009] Secondly, a method for preparing an acid-resistant, plate-breaking, highly active ultrafine composite mineral conditioner is provided, comprising the following steps: (1) Dry MgO is ultra-finely pulverized and sieved to obtain MgO micro-nano powder; (2) Natural CaSiO3 was mechanically activated to obtain ultrafine CaSiO3 powder; (3) Use high-speed airflow to shoot MgO micro-nano powder to ultrafine CaSiO3 powder, so that MgO is embedded in CaSiO3 or attached to the surface of CaSiO3 to obtain MgO-CaSiO3 mixture; (4) The MgO-CaSiO3 mixture undergoes a mechanochemical reaction under the action of a rolling equipment to obtain a Mg-Si-Ca composite. (5) After mechanically activating the phosphate rock powder, it is mixed with nano-silica and potassium hydroxide, and a mechanochemical reaction is carried out under the action of a rolling equipment to obtain a P-Si-K composite. (6) Mechanically activate the shell powder to obtain ultrafine shell powder; (7) The Mg-Si-Ca complex, P-Si-K complex and shell ultrafine powder are mixed at high speed to obtain a highly active ultrafine composite mineral conditioner.

[0010] Preferably, the equipment used for ultra-micro machining in steps (1), (2), (5), and (6) is one of a ball mill, a vibratory mill, a Raymond mill, or a vertical mill.

[0011] Preferably, the particle size D of the MgO ultrafine powder in step (1) is... 50 ≤5μm, the particle size D of the CaSiO3 ultrafine powder in step (2) 50 ≤9μm.

[0012] Preferably, in step (3), the device that generates high-speed airflow is one of fluidized bed airflow mill, airflow jet coating machine, jet-type airflow mill and fluidized coating machine, and the mass ratio of MgO micro-nano powder to CaSiO3 ultrafine powder is 10:25~30.

[0013] Preferably, in step (4), the crushing equipment is one of a double roll crusher, a high-pressure roller mill, a wheel mill, or a disc mill, and the mechanochemical reaction includes CaSiO3+MgO = MgSiO3+CaO and CaO+CO2=CaCO3.

[0014] Preferably, in step (5), the particle size D of the phosphate rock powder after mechanical activation is... 50≤5μm, the particle size of nano-silica is 10~50nm, and the mass ratio of phosphate rock powder, nano-silica, and potassium hydroxide is 10~30:4:1; the P-Si-K composite includes hydroxyapatite and potassium nickel fluorosilicate as new phases, obtained by the mechanochemical reaction of fluorapatite, the main component of phosphate rock powder, with nano-SiO2 and KOH, as shown in the following equation: Ca5(PO4)3F + OH - Ca5(PO4)3(OH) + F - SiO2 + F - + K + + H2O K Ni2Si4O 10 F2 + OH - (Weakly alkaline conditions) Preferably, in step (6), the particle size D of the shell ultrafine powder is... 50 ≤10μm.

[0015] Preferably, in step (7), the mass ratio of Mg-Si-Ca complex, P-Si-K complex and shell ultrafine powder is 50~60:25~10:25~30, and the equipment used for high-speed mixing is selected from one of high-speed dispersion mixer, high-shear mixer, vertical high-speed mixer, horizontal plow high-speed mixer and double planetary high-speed mixer.

[0016] Thirdly, an application of a method for preparing an acid-resistant, plate-breaking, highly active ultrafine composite mineral conditioner is provided.

[0017] The alkaline magnesium oxide, shell powder, and calcium carbonate contained in the highly active ultra-fine composite mineral conditioner can be fully mixed with soil particles during tillage, and can quickly react with free H+ in the soil solution. + An acid-base neutralization reaction occurs, consuming acidic substances in the soil and reducing soil acidity; calcium carbonate reacts with H+ in the soil. +During reactions with other minerals, carbon dioxide gas is released, forming numerous micropores in the soil. This effectively breaks up soil compaction and improves soil permeability. The ultra-fine particles in the highly active ultra-fine composite mineral conditioner fill soil gaps and form an isolation layer, reducing the adhesion between soil particles, promoting soil aggregate formation, and maintaining a loose soil condition. The calcium and magnesium ions released after the reaction of ultra-fine alkaline minerals work synergistically with the phosphates and silicates converted from phosphate rock powder. This not only replenishes essential nutrients for crops such as calcium, magnesium, phosphorus, and silicon in the soil, but also reduces the solubility and activity of heavy metal ions in the soil by utilizing the alkaline environment. At the same time, it reduces the activity of aluminum, manganese, and iron ions in the soil, inhibits the desilication and aluminum enrichment process in the soil, reduces the problem of soil acidification caused by mineral loss, blocks the intrinsic causes of soil acidification, and ensures the long-term stability of soil acidity.

[0018] Beneficial effects

[0019] The acid-resistant, plate-breaking, highly active ultra-micro composite mineral conditioner and its green preparation method of the present invention have multiple significant beneficial effects compared with existing soil conditioner technologies.

[0020] (1) The raw materials are activated by mechanical force, which on the one hand increases the contact area between the minerals and the acidic components of the soil, and significantly improves the reaction of free H+ in the soil. + On the one hand, the neutralization efficiency is high. On the other hand, the isolation effect of micro-nano and ultra-micro components, combined with the soil pores formed by gas generation during the preparation process, can effectively inhibit soil acidification, break up soil compaction, and simultaneously improve soil permeability and aggregate structure.

[0021] (2) Constructing a lasting carbon sink through mineral stabilization and aggregate protection. With the help of cutting-edge technologies such as X-ray micro-computed tomography, it is possible to see how pores of different sizes "recruit" very different microbial communities, which can significantly increase the sanctuary of anaerobic bacteria—small pores, which silently seal carbon elements.

[0022] (3) By using physical means such as high-speed air jetting and compaction to trigger a series of mechanochemical reactions, the inherent activity of minerals such as magnesium oxide and calcium silicate is activated, and a stable composite structure is formed. This can effectively prevent the conditioner components from being lost in the soil with water and greatly extend the soil improvement cycle. (4) The entire preparation process adopts physical processing methods without the addition of chemical reagents, avoiding secondary pollution. It is green and environmentally friendly, energy-saving and efficient, with simple procedures and easy to scale up production, which meets the needs of sustainable agricultural development. (5) The highly active ultra-micro composite mineral conditioner of the present invention is a natural mineral composite system with good compatibility with soil. Long-term application has no secondary harm. It optimizes the crop growth environment from the soil source, reduces the amount of heavy metals absorbed by crops, and improves the quality and safety of agricultural products. It has broad application prospects in agricultural production.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 Here is a scanning electron microscope image of the CaSiO3 ultrafine powder in Example 1; Figure 2 EDS image of CaSiO3 ultrafine powder in Example 1; Figure 3 The image shows the TEM-EDS image of the MgO-CaSiO3 mixture in Example 1. Figure 4 The image shows the TEM-EDS pattern of the P-Si-K composite in Example 1. Figure 5 This is the XRD pattern of the P-Si-K composite in Example 1; Figure 6 This is a particle size distribution diagram of soil aggregates during the early rice harvest period in an application example; Figure 7 These are three-dimensional images (a: 0~15m; b: 20~35cm; c: 40~55cm) of particulate organic matter (red) and porosity (blue) in the soil at different depths during the late rice harvest period in the X12 group of the application example. Figure 8 This is a two-dimensional image analysis cross-section of soil spatial variables during the late rice harvest period in the X12 group of the application example (a: original image; b: segmented image of pores and granular organic matter; c: image of pores and granular organic matter). Figure 9 This is a three-dimensional image of the soil pore size distribution during the late rice harvest period in group X12 of the application examples; Figure 10 Fourier transform infrared (FTIR) spectra of particulate organic matter and mineral-bound organic matter in the soil during the late rice harvest period of group X12 in the application example; Figure 11 The diagram shows the pore surface area distribution of soil aggregates at different depths in groups X1 and X12 during the late rice harvest period in the application example. Figure 12 The porosity distribution of soil aggregates at different depths in groups X1 and X12 during the late rice harvest period in the application example; Figure 13 The volume distribution of soil aggregates at different depths in groups X1 and X12 during the late rice harvest period in the application example is shown. Figure 14 The effects of different conditioner products on soil organic matter during the early rice harvest period in the application example; Figure 15 This study examines the effects of different conditioner products on soil organic matter during the late rice harvest period in an application example. Detailed Implementation

[0025] The present invention will be further described below. It should be noted that this embodiment is based on the present technical solution and provides detailed implementation methods and specific operation processes, but the present invention is not limited to this embodiment.

[0026] Example 1

[0027] This embodiment provides a method for preparing an acid-resistant, plate-breaking, highly active ultrafine composite mineral conditioner, including the following steps: (1) Use a ball mill to ultrafine grind the dried MgO to a particle size D 50 =5μm, thus obtaining MgO micro / nano powder; (2) Use Raymond mill to mechanically activate natural CaSiO3 to a particle size D 50 =9μm, thus obtaining ultrafine CaSiO3 powder; (3) Add MgO micro-nano powder and CaSiO3 ultrafine powder in a fluidized bed air jet mill at a mass ratio of 10:28. Use high-speed air jet to shoot MgO micro-nano powder toward ultrafine CaSiO3 powder, so that MgO is embedded in the interior of CaSiO3 or attached to the surface of CaSiO3 to obtain MgO-CaSiO3 mixture. (4) The MgO-CaSiO3 mixture undergoes a mechanochemical reaction under the action of a high-pressure roller mill to obtain a Mg-Si-Ca composite. (5) Use a ball mill to mechanically activate the phosphate rock powder to a particle size D. 50 =5μm, mixed with nano-silica with a particle size of 15±5nm and potassium hydroxide at a mass ratio of 10:4:1, and subjected to a mechanochemical reaction under the action of a ball mill to obtain a P-Si-K composite containing a new phase of hydroxyapatite and potassium nickel fluorosilicate. (6) Use a ball mill to ultrafine grind the shell powder to a particle size D. 50 =10μm, thus obtaining ultrafine seashell powder; (7) The Mg-Si-Ca complex, P-Si-K complex and ultrafine shell powder were thoroughly mixed in a high-speed dispersing mixer at a mass ratio of 55:20:25 to obtain a highly active ultrafine composite mineral conditioner, named Conditioner-1.

[0028] Example 2

[0029] This embodiment provides a method for preparing an acid-resistant, plate-breaking, highly active ultrafine composite mineral conditioner, including the following steps: (1) Use a ball mill to ultrafine grind the dried MgO to a particle size D. 50 =3μm, thus obtaining MgO micro / nano powder; (2) Use Raymond mill to mechanically activate natural CaSiO3 to a particle size D 50=7μm, thus obtaining ultrafine CaSiO3 powder; (3) Add MgO micro-nano powder and CaSiO3 ultrafine powder in a fluidized bed air jet mill at a mass ratio of 10:30. Use high-speed air jet to shoot MgO micro-nano powder toward ultrafine CaSiO3 powder, so that MgO is embedded in CaSiO3 or attached to the surface of CaSiO3 to obtain MgO-CaSiO3 mixture. (4) The MgO-CaSiO3 mixture undergoes a mechanochemical reaction under the action of a high-pressure roller mill to obtain a Mg-Si-Ca composite. (5) Use a ball mill to mechanically activate the phosphate rock powder to a particle size D. 50 =3μm, mixed with nano-silica with a particle size of 15±5nm and potassium hydroxide at a mass ratio of 30:4:1, and subjected to a mechanochemical reaction under the action of a ball mill to obtain a P-Si-K composite containing a new phase of hydroxyapatite and potassium nickel fluorosilicate. (6) Use a ball mill to ultrafine grind the shell powder to a particle size D. 50 =8μm, thus obtaining ultrafine seashell powder; (7) The Mg-Si-Ca complex, P-Si-K complex and ultrafine shell powder were thoroughly mixed in a high-speed dispersing mixer at a mass ratio of 55:15:30 to obtain a highly active ultrafine composite mineral conditioner, named Conditioner-2.

[0030] Example 3

[0031] This embodiment provides a method for preparing an acid-resistant, plate-breaking, highly active ultrafine composite mineral conditioner, including the following steps: (1) Dry MgO was ultra-finely pulverized using a ball mill and then sieved to obtain a particle size D. 50 MgO micro / nano powder with a diameter of 1μm; (2) Use Raymond mill to mechanically activate natural CaSiO3 to a particle size D 50 =5μm, thus obtaining ultrafine CaSiO3 powder; (3) Add MgO micro-nano powder and CaSiO3 ultrafine powder in a fluidized bed air jet mill at a mass ratio of 10:25. Use high-speed air jet to shoot MgO micro-nano powder toward ultrafine CaSiO3 powder, so that MgO is embedded in CaSiO3 or attached to the surface of CaSiO3 to obtain MgO-CaSiO3 mixture. (4) The MgO-CaSiO3 mixture undergoes a mechanochemical reaction under the action of a high-pressure roller mill to obtain a Mg-Si-Ca composite. (5) Use a ball mill to mechanically activate the phosphate rock powder to a particle size D. 50=1μm, mixed with nano-silica with a particle size of 15±5nm and potassium hydroxide at a mass ratio of 20:4:1, and subjected to a mechanochemical reaction under the action of a ball mill to obtain a P-Si-K composite containing a new phase of hydroxyapatite and potassium nickel fluorosilicate. (6) Use a ball mill to ultrafine grind the shell powder to a particle size D. 50 =6μm, thus obtaining ultrafine seashell powder; (7) The Mg-Si-Ca complex, P-Si-K complex and ultrafine shell powder were thoroughly mixed in a high-speed dispersing mixer at a mass ratio of 50:25:25 to obtain a highly active ultrafine composite mineral conditioner, named Conditioner-3.

[0032] Results Analysis The scanning electron microscope (SEM) and electronic spectrometer (EDS) images of the CaSiO3 ultrafine powder in Example 1 were determined using a ZEISS Gemini SEM 500 (SEM, Carl Zeiss Microscopy GmbH). The results are as follows: Figures 1-2 As shown; the TEM-EDS images of the MgO-CaSiO3 mixture and P-Si-K complex in Example 1 were determined using a JEM-2100F transmission electron microscope (TEM, HORIBA LabRAM HR Evolution). The results are shown below. Figure 3 and Figure 4 As shown; the phase composition of the P-Si-K composite was determined using X-ray powder diffraction (Smart Lab), and the results are as follows. Figure 5 As shown.

[0033] Scanning electron microscope image of CaSiO3 ultrafine powder ( Figure 1 As can be seen, the surface of CaSiO3 ultrafine powder has a rich porous structure. From Figure 2 The EDS image shows that natural CaSiO3 ultrafine powder contains not only Ca, Si, and O elements, but also Al and trace amounts of Mg. From the TEM-EDS image of the MgO-CaSiO3 mixture (…),… Figure 3 As can be seen, a large amount of Mg elements are distributed inside the MgO-CaSiO3 mixture, proving that some MgO is embedded into the pores of CaSiO3.

[0034] TEM-EDS image of the P-Si-K complex ( Figure 4 It can be observed that P, Si, K, and Ca elements are uniformly distributed inside the particles, combined with XRD patterns ( Figure 5 The presence of characteristic peaks in the hydroxyapatite and nickel potassium fluorosilicate phases indicates that apatite underwent a mechanochemical reaction with nano-SiO2 and KOH, generating the hydroxyapatite and nickel potassium fluorosilicate phases.

[0035] Application Example 1 This application example provides an application of an acid-resistant, plate-breaking, highly active ultrafine composite mineral conditioner.

[0036] Experimental Location: Innovation Experimental Base of Jinggangshan Red Soil Research Institute, Jiangxi Academy of Agricultural Sciences. The physicochemical properties of the basic soil samples are shown in Table 1. The experimental area is located in Xingqiao Town, Jizhou District, Ji'an City, Jiangxi Province. The multi-year average temperature is 17.1–18.6℃, with an annual average temperature of 18.3℃. The climate is relatively pleasant, with four distinct seasons: mild spring and autumn, hot summer, and relatively warm winter. Rainfall is abundant: the total annual precipitation is 1409 mm, with a multi-year average of 1487 mm. Rainfall is concentrated in spring and summer, providing sufficient water for agricultural production and vegetation growth.

[0037] Table 1. Physicochemical properties of soil samples from the early rice planting site

[0038] Experimental Design: Field plot experiments were conducted on early rice-late rice rotation using the acid-resistant, plate-breaking, highly active ultra-micro composite mineral conditioners prepared in Examples 1-3. A total of six groups were conducted, with three parallel experimental plots in each group. Each experimental plot covered an area of ​​20 m². 2 The experiment was conducted according to the fertilization method in Table 2, with a blank control group, a conventional fertilization control group, and a lime control group set up. Among them, the chemical fertilizer used for conventional fertilization was purchased from Jiangxi Shuaida Biotechnology Co., Ltd., with N, P2O5, and K2O contents of 15wt% each, and a total nutrient content of ≥45wt%.

[0039] Table 2 Fertilizer application rate for rice in experimental fields in Ji'an, Jiangxi Province

[0040] The field plot experiment of early rice-late rice rotation was carried out according to the experimental plan in Table 2. The physicochemical properties of soil pH, soil microbial biomass, enzyme activity and other data at the early rice harvest period are shown in Table 3.

[0041] Table 3 Soil physicochemical properties at early rice harvest period

[0042] Table 3 shows that during the early rice harvest period, there were significant differences in soil physicochemical properties among the groups treated with the acid-inhibiting and plate-breaking high-activity conditioner (X11, X12, X13), and between these groups and the control group (X0, X1, X2) (P<0.05). At the early rice harvest period, the pH values ​​of groups X2, X11, X12, and X13 increased by 0.30, 0.05, 0.19, and 0.48 units respectively compared to group X0, and by 0.71, 0.46, 0.6, and 0.89 units respectively compared to the conventional fertilization group (X1). This indicates that both lime and the acid-inhibiting and plate-breaking high-activity conditioner can increase soil pH, with group X13 showing the greatest increase. Therefore, conditioner-3 had the best acid-inhibiting effect on soil during the early rice harvest period, followed by the lime control group (X2) and conditioner-2 (X12).

[0043] Table 3 also shows that, during the early rice harvest period, compared with group X1, soil AP enzyme activity increased by 12.27% and 9.18% in groups X0 and X2, respectively, while soil AP enzyme activity decreased by 8.30%, 1.06%, and 45.50% in groups X11, X12, and X13, respectively. Compared with the conventional fertilization (X1) group, soil BG enzyme activity increased by 56.55%, 42.64%, 131.21%, and 132.85% in groups X0, X2, X11, and X12, respectively, while BG enzyme activity decreased in group X13. Compared with the X1 group, the soil CBH enzyme activity in the X0, X2, X11 and X12 groups increased by 61.68%, 47.51%, 19.45% and 47.96% respectively, while the soil CBH enzyme activity in the X13 group decreased by 29.88%. Compared with the conventional fertilization (X1) group, the soil LAP enzyme activity in the X2 and X13 groups increased by 12.34% and 9.41% respectively, while the activity in the X0, X11 and X12 groups decreased by 14.61%, 22.41% and 48.77% respectively.

[0044] Tables 4 and 5 show the yield composition of early rice and late rice in different conditioner test groups, respectively.

[0045] Table 4. Yield composition of early rice in different conditioner test groups

[0046] As shown in Table 4, lime (X2), conditioner-1 (X11), conditioner-2 (X12), and conditioner-3 (X13) all increased dry grain yield compared to conventional fertilization (X1). Compared with conventional fertilization (X1), X2 resulted in a slight decrease of 7.30% in the number of effective ears, an increase of 5.90% in the number of filled grains, and a dry grain yield of 5689 kg / ha, representing a yield increase of 1.81%; X11 resulted in a slight decrease of 11.06% in the number of effective ears, a decrease of 8.48% in the number of filled grains, and a dry grain yield of 6150 kg / ha, representing a yield increase of 10.06%; X12 resulted in a significant decrease of 26.67% in the number of effective ears, a decrease of 13.08% in the number of empty grains, a decrease of 20.88% in the number of filled grains, and a dry grain yield of 6576 kg / ha, representing a yield increase of 17.68%, the largest increase in yield; X13 resulted in a decrease of 17.18% in the number of effective ears, a decrease of 20.44% in the number of filled grains, and a dry grain yield of 6406 kg / ha, representing a yield increase of 14.64%.

[0047] Table 5. Yield composition of late-season rice in different conditioner test groups

[0048] Table 5 shows that the dry grain weight of late-season rice in groups X2, X11, X12, and X13 was higher than that in the blank control group (X0) and the conventional fertilization group (X1). Compared with the conventional fertilization group (X1), the effective panicle number in group X2 (lime control group) decreased slightly by 7.30%, the number of filled grains increased by 5.90%, and the stalk weight increased significantly by 132.14%, with a final dry grain yield of 9504.75g, an increase of 10.90% compared with group X1. This indicates that alkaline substances can optimize the yield composition of late-season rice. Compared with the conventional fertilization group (X1), the X11 group showed a significant increase in the number of effective panicles of early rice (18.38%), the number of empty grains (32.68%), the weight of filled grains (10.53%), and the weight of the stalk (74.40%), with a final dry grain yield of 8987.84 kg / ha, an increase of 4.81% compared with X1. The X12 group showed an increase in the number of effective panicles (5.79%), the number of filled grains (4.91%), and the weight of the stalk (129.75%), with a final dry grain yield of 9538.12 kg / ha, a significant increase of 11.22% compared with X1. The X13 group showed an increase in the number of effective panicles of late rice (10.32%), the number of filled grains (19.35%), the weight of filled grains (16.15%), and the weight of the stalk (108.81%), with a final dry grain yield of 9071.18 kg / ha, an increase of 5.81% compared with X1.

[0049] As can be seen from the above, applying acid-inhibiting and high-activity conditioners to the soil is beneficial to increasing the yield of early and late rice and optimizing the yield composition of early and late rice.

[0050] The particle size distribution of soil aggregates at the early rice harvest period in the six experimental groups in the application example is as follows: Figure 6 As shown in Table 6.

[0051] Table 6. Percentage of soil aggregate size distribution at early rice harvest time in different experimental groups (%) in application examples

[0052] from Figure 6 As shown in Table 6, different experimental groups significantly affected the particle size distribution of soil aggregates. Among aggregates larger than 2 mm, lime (X2) showed the largest increase, followed by conditioner-2 (X12), increasing by approximately 32.8% and 8.9% respectively compared to conventional fertilization (X1); only the control group (X0) showed a decrease of 40.0%. Among aggregates of 2–0.25 mm, only the control group (X0) and conditioner-1 (X11) showed a slight increase in proportion, while conditioner-3 (X13) showed the largest decrease of 45.9%, followed by X12 with a decrease of 41.6%. Among small aggregates of 0.25–0.053 mm, only the control group (X0) showed a significant increase of 84.4%; all other treatments showed a decrease, with X2 and X13 decreasing by 43.3% and 37.3% respectively, and X12 decreasing by 21.6%. Among the total proportion of macroaggregates >0.25mm, X2 increased by 12.0%; although X12 decreased by 15.1% compared to conventional fertilization (X1), it showed balanced performance among conditioner treatments. In summary, although X12 had a lower total proportion of macroaggregates than X1, it could increase the proportion of macroaggregates >2mm and increase the proportion of small aggregates, making it a key research target for conditioner formulation optimization.

[0053] In an application example, soil samples (X12 group) were taken during the late rice harvest period. Three-dimensional images of soil particles and pores at different depths were determined using industrial CT three-dimensional reconstruction methods. The results are as follows: Figure 7 As shown; a two-dimensional image analysis cross-section of soil spatial variables determined by CT two-dimensional cross-sectional imaging and spatial analysis methods, the results are as follows. Figure 8 As shown; the three-dimensional image of soil pore size distribution was determined by CT pore size distribution three-dimensional reconstruction method, and the results are as follows. Figure 9 As shown; Fourier transform infrared spectroscopy was used to determine the Fourier transform infrared spectra of particulate organic matter and mineral-bound organic matter in the soil, and the results are as follows. Figure 10 As shown.

[0054] from Figures 7-10 It can be seen that under the X12 treatment, there is a significant vertical differentiation in the distribution of soil particulate organic matter and pores: the top 0-20cm layer is rich in particulate organic matter and has a well-developed pore structure, and the content of both decreases with increasing soil depth; pores and particulate organic matter have a significant spatial coupling relationship and a high degree of location correlation; X12 can optimize the soil pore size composition and increase the pore ratio; at the same time, it can promote the combination of organic matter and minerals and enhance the stability of soil organic matter.

[0055] During the late rice harvest period, the pore surface area distribution, porosity distribution, and volume distribution of soil aggregates at different depths in group X1 (conventional fertilization) and group X12 (conditioner-2) are as follows: Figures 11-13 As shown.

[0056] Depend on Figures 11-13 It was found that, compared with the conventional fertilization group (X1), the X12 group had a more significant impact on the pore surface area distribution, porosity distribution, and volume distribution of soil aggregates at different depths (P<0.05). In the middle soil layer (20–35 cm) and the deep soil layer (40–55 cm), the pore surface area of ​​the X12 group was >1 mm². 2 1~0.5mm 2 <0.5mm 2 The number of soil aggregates in group X12 was significantly increased compared to group X1; the number of soil aggregates with pore sizes >1mm, 1~0.5mm, and <0.5mm in group X12 was significantly increased compared to group X1; the number of soil aggregates with a volume >1mm in group X12 was significantly increased compared to group X1. 3 1~0.5mm 3 <0.5mm 3 The number of soil aggregates in group X12 was significantly increased compared to group X1. In the shallow soil layer of 0-15cm, all indicators of soil aggregates in group X12 were lower than those in group X1, but the overall level remained relatively stable. Overall, after applying the acid-inhibiting and plate-breaking high-activity conditioner, group X12 can precisely and effectively improve the water retention, fertilizer retention, aeration, and stress resistance of medium and deep soils. In farmland improvement or remediation projects with compacted medium and deep soil structure and low fertility, the effect is significantly better than that of group X1, which uses conventional fertilization.

[0057] The effects of acid-inhibiting and plate-breaking conditioners on soil organic matter content of early rice and late rice are as follows: Figure 14 and Figure 15 As shown.

[0058] Depend on Figure 14 The results showed that different conditioners significantly affected the organic matter content of early rice soil. Compared with X0, X11, X12, and X13 showed significantly higher levels of organic matter, increasing by 21.41%, 19.16%, and 22.49%, respectively. Compared with X1, X11, X12, and X13 increased the organic matter content by 11.42%, 9.17%, and 12.5%, respectively. The study indicates that applying different conditioners to early rice can promote soil organic matter production, with conditioner X13 showing the most significant effect.

[0059] Depend on Figure 15The results showed that different conditioners significantly affected soil organic matter in late-season rice. Compared with the blank control X0, X12 and X13 showed significantly higher levels of organic matter, increasing by 97.88% and 97.39%, respectively. Compared with conventional fertilization (X1), X12 and X13 increased soil organic matter by 15.00% and 25.09%, respectively. The study indicates that applying different conditioners during late-season rice cultivation can promote soil organic matter production, with conditioner X13 showing the most significant effect.

[0060] In summary, among all the above-mentioned treatment experiments with acid-blocking and plate-breaking high-activity conditioners, considering factors such as soil acid-blocking effect, cost, and yield composition, the acid-blocking and plate-breaking high-activity ultra-micro composite conditioner-2 formula is the best, and the dosage of 150 kg / mu is the most suitable. It can not only prevent soil acidification, but also has a good effect on regulating soil enzyme activity and soil porosity, resulting in a significant increase in yield. Although its effect is comparable to that of lime, it solves the bottleneck problem of lime application.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A highly active ultrafine composite mineral conditioner for acid resistance and plate breaking, characterized in that, Including magnesium oxide, natural calcium silicate, phosphate rock powder, nano-silica, potassium hydroxide, and shell powder.

2. The preparation method of the highly active ultrafine composite mineral conditioner for acid-resistant plate breaking as described in claim 1, characterized in that, Includes the following steps: (1) Dry MgO is mechanically activated and then sieved to obtain MgO ultrafine powder; (2) Natural CaSiO3 is mechanically activated to obtain CaSiO3 ultrafine powder; (3) Use a high-speed airflow to shoot MgO ultrafine powder toward CaSiO3 ultrafine powder, so that MgO is embedded in the interior of CaSiO3 or attached to the surface of CaSiO3 to obtain a MgO-CaSiO3 mixture. (4) The MgO-CaSiO3 mixture undergoes a mechanochemical reaction under the action of a rolling equipment to obtain a Mg-Si-Ca composite. (5) After mechanically activating the phosphate rock powder, it is mixed with nano-SiO2 and KOH, and a mechanochemical reaction occurs under the action of a rolling equipment to obtain a P-Si-K composite. (6) Mechanically activate the shell powder to obtain shell ultrafine powder; (7) The Mg-Si-Ca complex, P-Si-K complex and shell ultrafine powder are mixed at high speed to obtain a highly active composite mineral conditioner.

3. The preparation method according to claim 2, characterized in that, The equipment used for ultra-micro machining in steps (1), (2), (5), and (6) is one of the following: ball mill, vibratory mill, Raymond mill, or vertical mill.

4. The preparation method according to claim 2, characterized in that, The particle size D of the MgO ultrafine powder in step (1) 50 ≤5μm, the particle size D of the CaSiO3 ultrafine powder in step (2) 50 ≤9μm.

5. The preparation method according to claim 2, characterized in that, In step (3), the equipment that generates high-speed airflow is one of fluidized bed air mill, air jet coating machine, jet mill and fluidized coating machine, and the mass ratio of MgO micro-nano powder to CaSiO3 ultrafine powder is 10:25~30.

6. The preparation method according to claim 2, characterized in that, In step (4), the crushing equipment is one of a double roll crusher, a high-pressure roller mill, a wheel mill, or a disc mill, and the mechanochemical reactions include CaSiO3+MgO = MgSiO3+CaO and CaO+CO2=CaCO3.

7. The preparation method according to claim 2, characterized in that, In step (5), the particle size D of the phosphate rock powder after mechanical activation is... 50 The particle size of nano-silica is 10~50nm, and the mass ratio of phosphate rock powder, nano-silica and potassium hydroxide is 10~30:4:1; the P-Si-K composite includes hydroxyapatite and potassium nickel fluorosilicate as new phases.

8. The preparation method according to claim 2, characterized in that, In step (6), the particle size D of the shell ultrafine powder 50 ≤10μm.

9. The preparation method according to claim 2, characterized in that, In step (7), the mass ratio of Mg-Si-Ca complex, P-Si-K complex and shell ultrafine powder is 50~60:25~10:25~30. The equipment used for high-speed mixing is selected from one of the following: high-speed dispersing mixer, high-shear mixer, vertical high-speed mixer, horizontal plow-type high-speed mixer, and double planetary high-speed mixer.

10. The application of the acid-resistant, plate-breaking, highly active composite mineral conditioner as described in any one of claims 2 to 9.

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