A multifunctional acidic soil conditioner and its preparation and application method

Abstract

The invention relates to the technical field of preparation of acidic soil conditioners, and in particular to a multifunctional acidic soil conditioner and a preparation and application method thereof. The multifunctional acidic soil conditioner is composed of potassium feldspar, alkaline residue and a synergist in a mass ratio of 1:1.3-1.7:1-2; the preparation method of the multifunctional acidic soil conditioner comprises: S1', pretreatment and S2', preparation of the soil conditioner; the application method is to apply the soil conditioner in the field; the invention prepares a high-activity acid-changing and fertilizing multifunctional novel conditioner by optimizing material ratio and alkali-heat activation conditions, the conditioner can effectively balance the content of alkaline substances and active nutrients such as potassium, calcium and magnesium, significantly improve the effective K, Ca and Mg content of the soil while improving the soil acidity, and realize the simultaneous improvement of pH value and fertility of acidic soil.

Description

Technical Field

[0001] The invention relates to the technical field of acidic soil conditioner preparation, and in particular to a multifunctional acidic soil conditioner and a preparation and application method thereof. Background Art

[0002] Acidic soil conditioner is a substance used to improve the properties of acidic soil. It mainly adjusts the pH of the soil to make it more neutral or close to the ideal state, so as to provide a more favorable environment for plant growth. Acidic soil conditioners are usually composed of natural or synthetic substances, such as lime substances (such as limestone powder, quicklime, slaked lime, etc.), and other mineral source conditioners such as zeolite, diatomaceous earth, etc. The main functions of acidic soil conditioners include: neutralizing soil acidity, increasing soil pH, replenishing active calcium and magnesium and other trace elements in the soil; helping the reproduction of beneficial microorganisms in the soil and the activation of nutrients; promoting the formation of soil aggregate structure, preventing soil compaction, enhancing enzyme activity, accelerating photosynthesis, and improving the utilization rate of chemical fertilizers; improving crop resistance, promoting early flowering and fruiting of crops, and extending the fruiting period. When used, acidic soil conditioners are generally applied as base fertilizers, and the specific amount needs to be increased or decreased according to the acidity of the soil.

[0003] In addition to soil acid damage, the low content of nutrients such as K, Ca, and Mg in acidic soils also limits the growth of crops. The traditional lime improvement method has a significant effect on improving soil acidity, but it will also aggravate the loss of nutrients such as K and Mg in the soil, causing nutrient imbalance. The multifunctional acidic soil conditioners currently on the market for acidification and nutrient supplementation are usually prepared by a simple compounding method of mineral raw materials such as lime or potassium feldspar. The alkaline substances and nutrient activity are limited, especially the activity of K. The demand for potassium in the early stage of crop growth is relatively high, and low-activity K sources are difficult to meet the crop's demand for K nutrition in the current season. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a multifunctional acidic soil conditioner and a preparation and application method thereof.

[0005] The technical scheme of the invention is: a multifunctional acidic soil conditioner, which is composed of potassium feldspar, alkali residue and synergist in a mass ratio of 1:1.3-1.7:1-2.

[0006] Furthermore, the active potassium enhancer is Suaeda salsa straw, and the alkalinity enhancer is oyster shell powder;

[0007] Description: The addition of Suaeda salsa straw to acidic soil conditioners can further increase the active K content in the soil conditioner, enhance soil fertility and structural stability, and promote the healthy growth of crops. Through experiments, we found that the addition of oyster shell powder can significantly increase the alkalinity of the conditioner while ensuring the activation of K in the conditioner. While increasing the effective K in the soil, it also plays a further synergistic role in improving the acidity of acidic soils, thereby improving soil quality.

[0008] Furthermore, it also includes sepiolite and a calcium lignosulfonate solution with a mass concentration of 4-6%, wherein the mass ratio of the sepiolite, the calcium lignosulfonate solution and potassium feldspar is 0.1-0.2:0.2-0.3:1;

[0009] Description: Mineral source conditioners such as sepiolite can neutralize acidic substances in the soil through their own alkaline substances, increase the pH value of the soil, and can also effectively adsorb harmful ions such as heavy metals, active Al, etc., reducing the impact of harmful substances on plant growth. This adsorption performance plays a key role in soil conditioning, helping to create a healthier and more suitable soil environment for crop growth and reduce the adverse effects of soil acidification.

[0010] Calcium lignosulfonate solution is a multi-component high molecular polymer anionic surfactant with strong dispersibility, adhesion and chelation. It can effectively improve the binding force of each component in the soil conditioner and enhance the stability and durability of the soil conditioner. At the same time, calcium lignosulfonate can also adjust the pH of the soil, help improve the environment of acidic soil, promote the reproduction and activity of soil microorganisms, and promote the growth and development of plants. In addition, calcium lignosulfonate can enhance the binding force between the soil conditioner and soil particles, so that the conditioner is more evenly distributed in the soil, thereby improving the utilization rate and effect of the conditioner.

[0011] The present invention also provides a method for preparing a multifunctional acidic soil conditioner, which is used to prepare a multifunctional acidic soil conditioner, comprising the following steps:

[0012] S1', preprocessing

[0013] Grind potash feldspar powder, alkali residue powder and synergist with a particle size of less than 0.15 mm respectively, then mix the three to obtain a mixed powder, add clean water at a solid-liquid mass ratio of 1:1-2, soak and stir for 0.5-2h, then treat at a microwave power of 600-650W for 0.5-1h until the water content of the mixed powder is 8-10%, and obtain a material powder for standby use;

[0014] S2', Preparation of soil conditioner

[0015] The material powder is added into a calcining furnace and calcined at 850-950° C. for 1.5-2.5 hours to obtain a mixture; sepiolite is then added into the mixture for mixing, and after mixing, a calcium wood sulfonate solution is sprayed at a rate of 30-50 mL / min through a disc granulator, and dried at a temperature of 45-50° C. to a water content of 4-6%, and then granulated and sieved to obtain particles with a particle size of 4-6 mm, which is a soil conditioner;

[0016] Description: Water treatment can promote effective functional elements such as Na + , Ca 2+ , Cl- soluble components are fully mixed with mineral phases such as potassium feldspar to promote K activation during the calcination process. Since water vapor generated by excessive moisture during the calcination process damages the furnace heating elements, the microwave function can further promote mixing and remove excess moisture, thereby protecting the calcination furnace; the addition of sepiolite can reduce the permeability of the soil, help reduce the loss of water and nutrients, and improve the soil's water retention capacity and fertilizer efficiency. In addition, the addition of sepiolite can also promote the stability of organic matter, which can have a positive effect on the formation of soil aggregate structure, further promoting the preparation efficiency and effectiveness of acidic soil conditioners.

[0017] Furthermore, a method for applying a multifunctional acidic soil conditioner comprises the following steps:

[0018] S1. Determine the acid buffer capacity of the soil to be treated, recorded as pHBC, in mmol / kg / pH; determine the initial pH of the soil to be treated, recorded as pH ini ; Determine the acid neutralization capacity at the corresponding temperature, denoted as C, in mol / kg; denoted as pH the expected pH of the soil after treatment tar , the value is 5.0~6.0;

[0019] S2. Then, the estimated field dosage M of the multifunctional acidic soil conditioner is calculated according to formula (1), in kg / mu;

[0020] M=pHBC×[(pH tar -pH ini -0.1307) / 0.6346]×173.16 / C (1)

[0021] S3. Calculate the amount of potassium fertilizer N based on the estimated field dosage M of the acidic soil conditioner and formula (2), in kg / mu;

[0022] N=(conventional potassium fertilizer K 2 O dosage -M×0.021) ×149 / 94 (2)

[0023] S4, then evenly applying M kg / mu of multifunctional acidic soil conditioner and N kg / mu of potash fertilizer to the soil to be treated, and turning over the 0-20 cm surface soil to obtain treated soil, thereby achieving conditioning of the acidic soil;

[0024] Among them, conventional potassium fertilizer K 2 The amount of O is the amount of fertilizer that local farmers are used to applying, which is generally 7-10 kg / mu;

[0025] Note: The above calculation method can accurately calculate the dosage of acidic soil conditioner to maximize its effectiveness, while reducing the dosage of potassium fertilizer to achieve cost savings and increase efficiency.

[0026] Furthermore, a soil conditioner is loaded on the surface of the modified biochar and then put into use, wherein the loading amount of the soil conditioner is 50-70%;

[0027] The loading method is:

[0028] The soil conditioner powder is added to water at a concentration ratio of 1 g: 8-12 mL, stirred and mixed to obtain a dispersion, and then the modified biochar is added at a ratio of 20 g: 240-360 mL of the modified biochar: dispersion, and ultrasonic-assisted treatment is performed for 30 minutes. After the treatment is completed, the modified biochar loaded with the soil conditioner is placed in a drying oven at 50-60° C. to dry, thereby obtaining the modified biochar with the soil conditioner loaded on the surface;

[0029] Among them, in the ultrasonic-assisted treatment process, the ultrasonic treatment time is 25 to 45 minutes, the ultrasonic frequency is 25 to 35 kHz, and the power is 80 to 100 W;

[0030] Note: The effect of acidic soil conditioner can be further optimized by loading the soil conditioner on the surface of biochar under ultrasonic conditions before application. Ultrasonic treatment can improve the bonding between soil particles and biochar, so that the conditioner can not only increase the active K content in the soil and improve the soil acidity, but also enhance the soil's ability to retain fertilizer by increasing the amount of negative charge on the surface.

[0031] Furthermore, the preparation method of the modified biochar is as follows: 20g of biochar is immersed in 50mL of KOH solution with a mass concentration of 50g / L to 100g / L for surface treatment, the immersion time is 2 to 5h, stirring once every 1h during the immersion process, and then 1.00 to 1.50g of citric acid solid is weighed and slowly added to 25mL of deionized water, and after it is completely dissolved, the citric acid solution is slowly added to the biochar suspension, mixed and placed in a water bath at 80 to 85°C for heating and stirring for 2h, and then 0.4 to 0.6g of D-fructose 1,6-bisphosphate trisodium salt hydrate is dispersed in 25mL of water, ultrasonically mixed, and then added dropwise to the biochar suspension, heated in a water bath and continued to stir for 30 to 50min, and then dried in a drying oven at 50 to 60°C to obtain the modified biochar;

[0032] Description: D-fructose 1,6-bisphosphate trisodium salt hydrate acts as a template to interact with biochar, promoting the development of the microstructure inside the biochar and forming a multi-level pore structure, including micropores, mesopores and macropores. These pore structures have a positive effect on the adsorption performance of biochar, and can also increase the specific surface area and improve the distribution of surface functional groups, thereby enhancing its adsorption capacity for harmful substances in acidic soils and soil improvement effects. The adsorption performance of modified biochar helps to maintain the effectiveness of the active ingredients in the conditioner and reduce its loss in the soil, thereby improving the soil's acid-base balance and fertility.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The present invention utilizes alkaline industrial and agricultural byproducts such as alkali residue and oyster shells and green and low-cost raw materials such as low-grade potassium feldspar, and optimizes the material ratio and "alkali heat" activation conditions to prepare a highly active acid-changing and fertilizing multifunctional new conditioning agent (FAO 900 ). This conditioner can effectively balance the content of alkaline substances and active nutrients such as potassium, calcium, and magnesium. While improving soil acidity, it can significantly increase the effective K, Ca, and Mg content in the soil, thereby achieving a simultaneous increase in the pH and fertility of acidic soils; the new conditioner FAO 900 Exchangeable K + , Ca 2+ and Mg 2+ They increased by 70%, 882% and 376% respectively. 900 It also significantly improves the soil exchangeability K + , but its exchangeable Ca 2+ and Mg 2+ The improvement effect is limited. 900 Can better reduce soil acidity and effectively balance soil K + , Ca 2+ and Mg 2+content, improving soil fertility levels.

[0035] (2) The present invention further increases the cation exchange capacity (CEC) of the soil by loading D-fructose 1,6-bisphosphate trisodium salt hydrate on the surface of biochar with high porosity and specific surface area, thereby improving the soil's adsorption and retention capacity for cationic nutrients such as potassium ions, and because the stable carbon structure formed by biochar during pyrolysis is not easily decomposed by microorganisms, it can be stored in the soil for a long time, playing a carbon fixation role, while providing a living space for soil microorganisms and promoting the growth of soil microorganisms. In addition, D-fructose 1,6-bisphosphate trisodium salt hydrate as a template interacts with biochar, which can promote the formation of a multi-level pore structure inside the biochar, further improve the effectiveness of the active ingredients in the conditioner, reduce its loss in the soil, and thus improve the acid-base balance and fertility of the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the effect of the preparation conditions (ratio, temperature) of potassium feldspar, alkali residue and oyster shell powder on the active K and alkaline substance content of the conditioning agent;

[0037] Figure 2 This is a graph showing the effect of the ratio of potassium feldspar to alkali residue and oyster shell powder and calcination temperature on the acid neutralization capacity;

[0038] Figure 3 is the effect of calcination temperature on the activity K of the improver at the optimal ratio of potassium feldspar, alkali residue and oyster shell powder of 1:1.5:1.5;

[0039] Figure 4 This is the effect of calcination temperature on the acid neutralization capacity of potassium feldspar, alkali residue and oyster shell powder at the optimal ratio of 1:1.5:1.5;

[0040] Figure 5 This is a diagram showing the effect of the acidic soil conditioner prepared by the present invention on improving the pH of the soil;

[0041] Figure 6 This is a diagram showing the effect of the acidic soil conditioner prepared by the present invention on reducing soil exchangeable acid;

[0042] Figure 7 The acidic soil conditioner prepared by the present invention has an effect on the effective state K of the soil under different calcination temperatures and ratio conditions. + The lifting effect diagram;

[0043] Figure 8 The acidic soil conditioner prepared by the present invention has an effect on the effective Ca2+ state of the soil under different calcination temperatures and ratio conditions. 2+ The lifting effect diagram;

[0044] Fig. 9 The acidic soil conditioner prepared by the present invention has an effect on the effective Mg content of the soil under different calcination temperatures and ratios. 2+ The lifting effect diagram;

[0045] Fig.10 For the pretreatment of the present invention, water (FAO 900 ) and without adding water (FAOW 900 ) is a bar graph showing the active K content in the conditioner prepared. DETAILED DESCRIPTION

[0046] In order to further illustrate the method and effect of the present invention, the technical solution of the present invention will be clearly and completely described in combination with experiments.

[0047] Embodiment 1: A multifunctional acidic soil conditioner, comprising potassium feldspar, alkali residue and oyster shell powder in a mass ratio of 1:

[0048] 1.5:1.5 composition;

[0049] This embodiment also provides a method for preparing a multifunctional acidic soil conditioner, which is used to prepare the multifunctional acidic soil conditioner, comprising the following steps:

[0050] S1', preprocessing

[0051] Grind potassium feldspar powder, oyster shell powder and alkali residue powder respectively to prepare a particle size of 0.15 mm, then mix the three to obtain a mixed powder for later use;

[0052] S2', Preparation of soil conditioner

[0053] The mixed powder is added into a calcining furnace and calcined at 900°C for 2 hours to obtain a mixture, which is a powdered conditioning agent, denoted as FAO. 900 ;

[0054] The application of a multifunctional acidic soil conditioner comprises the following steps:

[0055] S1. Determine the acid buffer capacity of the soil to be treated, recorded as pHBC, in mmol / kg / pH; determine the initial pH of the soil to be treated, recorded as pH ini ; Determine the acid neutralization capacity at the corresponding temperature, denoted as C, in mol / kg; denoted as pH the expected pH of the soil after treatment tar , the value is 5.1;

[0056] S2. Then, the estimated field dosage M of the multifunctional acidic soil conditioner is calculated according to formula (1), in kg / mu;

[0057] M=pHBC×[(pH tar-pH ini -0.1307) / 0.6346]×173.16 / C (1)

[0058] S3. Calculate the estimated amount of potassium fertilizer N based on the estimated field amount of acidic soil conditioner M and formula (2), in kg / mu;

[0059] N=(conventional potassium fertilizer K 2 O dosage -M×0.021) ×149 / 94 (2)

[0060] S4, then applying M kg / mu of multifunctional acidic soil conditioner and N kg / mu of potash fertilizer to the soil to be treated, and turning over 10 cm of the surface soil to obtain treated soil, thereby achieving conditioning of the acidic soil;

[0061] In this example, the initial soil pH ini =4.63, target pH tar =5.10, soil pHBC=27.82mmol / kg / pH; FAO 900 The C under is 13.09 mol / kg;

[0062] According to M = 27.82 × (5.1-4.63-0.1307) / 0.6346 × 173.16 / 13.09 = 196.77 kg / mu;

[0063]

[0064] Based on FAO 900 The field usage can be further calculated as follows: Estimated KCl usage N (kg / mu) = (10-196.77×0.021)×149 / 94 = 9.30kg / mu.

[0065] Example 2: Different from Example 1, a multifunctional acidic soil conditioner is composed of potassium feldspar, alkali residue and oyster shell powder in a mass ratio of 1:1.3:1.

[0066] Example 3: Different from Example 1, a multifunctional acidic soil conditioner is composed of potassium feldspar, alkali residue and oyster shell powder in a mass ratio of 1:1.7:2.

[0067] Example 4: Different from Example 1, in step S1', the mixed powder is added to clean water at a solid-liquid mass ratio of 1:1 and stirred for 0.5 h, and then treated at a microwave power of 600 W for 0.5 h until the water content of the mixed powder is 10%, thereby obtaining a material powder for standby use.

[0068] Example 5: Different from Example 4, in step S1', the mixed powder is added to clean water according to the solid-liquid mass ratio of the mixed powder to water being 1:1.5, soaked and stirred for 1.2 hours, and then treated at a microwave power of 625 W for 0.7 hours until the water content of the oyster shell powder is 9%, and then set aside.

[0069] Example 6: Different from Example 4, in step S1', the mixed powder is added to clean water according to a solid-liquid mass ratio of the mixed powder to water of 1:2, soaked and stirred for 2 hours, and then treated at a microwave power of 650 W for 2 hours until the water content of the oyster shell powder is 8%, and then set aside.

[0070] Example 7: Different from Example 5, in step S2', the material powder is added into the calcining furnace and calcined at 850°C for 2.5h to obtain a mixture, which is a powdered conditioner.

[0071] Example 8: Different from Example 5, in step S2', the material powder is added into the calcining furnace and calcined at 950°C for 1.5h to obtain a mixture, which is a powdered conditioning agent.

[0072] Example 9: Different from Example 5, this example further comprises sepiolite and a calcium lignosulfonate solution with a mass concentration of 5%, and the mass ratio of sepiolite, calcium lignosulfonate solution and potassium feldspar is 0.15:0.25:1;

[0073] This embodiment also provides a method for preparing a multifunctional acidic soil conditioner, which is used to prepare the multifunctional acidic soil conditioner, comprising the following steps:

[0074] S1', preprocessing

[0075] Grind potassium feldspar powder, oyster shell powder and alkali residue powder with a particle size of 0.15 mm respectively, then mix the three to obtain a mixed powder, add clean water at a solid-liquid mass ratio of 2:3, soak and stir for 1.2 hours, and then treat at a microwave power of 625 W for 0.7 hours until the water content of the mixed powder is 9%, to obtain a material powder for standby use;

[0076] S2', Preparation of soil conditioner

[0077] The material powder is added into a calcining furnace and calcined at 900°C for 2 hours to obtain a mixture; sepiolite is then added into the mixture for mixing, and after mixing, the calcium wood sulfonate solution is sprayed at a rate of 40 mL / min through a disc granulator, and dried at a temperature of 47°C to a moisture content of 5%, and then granulated and sieved to obtain particles with a particle size of 5 mm, which is a soil conditioner.

[0078] Example 10: Different from Example 9, the mass ratio of sepiolite, calcium lignosulfonate solution with a mass concentration of 4%, and potassium feldspar is 0.1:0.2:1.

[0079] Example 11: Different from Example 9, the mass ratio of sepiolite, calcium lignosulfonate solution with a mass concentration of 6%, and potassium feldspar is 0.2:0.3:1.

[0080] Example 12: Based on Example 1, soil conditioner powder is loaded on the surface of modified biochar and then put into use, and the loading amount of soil conditioner powder is 60%;

[0081] The loading method is as follows: adding soil conditioner powder into water at a concentration ratio of 1 g: 10 mL, stirring and mixing to obtain a dispersion, then adding modified biochar at a ratio of 20 g: 300 mL of modified biochar: dispersion, and performing ultrasonic-assisted treatment. After the treatment, the modified biochar loaded with the soil conditioner is placed in a 55°C oven for drying to obtain modified biochar with the soil conditioner loaded on the surface; wherein, during the ultrasonic-assisted treatment, the ultrasonic treatment time is 35 min, the ultrasonic frequency is 30 kHz, and the power is 90 W;

[0082] The preparation method of modified biochar is as follows: 20g of biochar is immersed in 50mL of KOH solution with a mass concentration of 50g / L for surface treatment. The immersion time is 3h, and the mixture is stirred once every 1h during the immersion process. Then 1.25g of citric acid solid is weighed and slowly added to 25mL of deionized water. After it is completely dissolved, the citric acid solution is slowly added to the biochar suspension, mixed and placed in a water bath at 80°C for heating, stirring and ultrasonication for 2h, and then 0.5g of D-fructose 1,6-bisphosphate trisodium salt hydrate is dispersed in 25mL of water, ultrasonically mixed, and then added dropwise to the biochar suspension. After heating and stirring in a water bath for 40min, the mixture is dried in a drying oven at 55°C to obtain modified biochar.

[0083] Example 13: Different from Example 12, the soil conditioner is added to water at a concentration ratio of 1g:8mL, stirred and mixed to obtain a dispersion, and then the modified biochar is added at a ratio of modified biochar: dispersion of 20g:240mL, and ultrasonic-assisted treatment is performed. After the treatment, the modified activated carbon loaded with the soil conditioner is placed in a drying oven at 50°C to obtain the modified biochar with the soil conditioner loaded on the surface.

[0084] Example 14: Different from Example 12, the soil conditioner is added to water at a concentration ratio of 1 g: 12 mL, stirred and mixed to obtain a dispersion, and then the modified biochar is added at a ratio of 20 g: 360 mL of modified biochar: dispersion, and ultrasonic-assisted treatment is performed. After the treatment, the modified activated carbon loaded with the soil conditioner is placed in a drying oven at 60°C to obtain the modified biochar with the soil conditioner loaded on the surface.

[0085] Example 15: Different from Example 12, during the ultrasonic-assisted treatment, the ultrasonic treatment time is 45 min, the ultrasonic frequency is 25 kHz, and the power is 80 W.

[0086] Example 16: Different from Example 12, during the ultrasonic-assisted treatment, the ultrasonic treatment time is 25 min, the ultrasonic frequency is 35 kHz, and the power is 100 W.

[0087] Example 17: Different from Example 12, 20g of biochar was immersed in 50mL of KOH solution with a mass concentration of 50g / L for surface treatment. The immersion time was 2h. The solution was stirred every 1h during the immersion process. Then 1.00g of citric acid solid was weighed and slowly added to 25mL of deionized water. After it was completely dissolved, the citric acid solution was slowly added to the biochar suspension. The mixture was placed in a water bath at 80°C and heated with stirring and ultrasound for 2h. Then 0.4g of D-fructose 1,6-bisphosphate trisodium salt hydrate was dispersed in 25mL of water. After ultrasonic mixing, the mixture was added dropwise to the biochar suspension. The mixture was heated in a water bath and continued to be stirred and ultrasounded for 50min. Then, the mixture was dried in a drying oven at 60°C to obtain modified biochar.

[0088] Example 18: Different from Example 12, 20g of biochar was immersed in 50mL of KOH solution with a mass concentration of 100g / L for surface treatment. The immersion time was 5h. The solution was stirred every 1h during the immersion process. Then, 1.50g of citric acid solid was weighed and slowly added to 25mL of deionized water. After it was completely dissolved, the citric acid solution was slowly added to the biochar suspension. The mixture was mixed and placed in a water bath at 85°C for heating and stirring for 2h. Then, 0.6g of D-fructose 1,6-bisphosphate trisodium salt hydrate was dispersed in 25mL of water. After ultrasonic mixing, the mixture was added dropwise to the biochar suspension. After heating and stirring in a water bath for 50min, the mixture was dried in a drying oven at 50°C to obtain modified biochar.

[0089] Experimental Example: The description of this experimental example is based on the scheme described in Example 1, and is intended to illustrate the practical application effect of the present invention. 900It represents a multifunctional acidic soil conditioner obtained by calcining potassium feldspar, alkali residue and oyster shell powder at a calcination temperature of 900°C; wherein F is potassium feldspar, A is alkali residue, O is oyster shell powder; ANC is acid neutralization capacity;

[0090] Depend on Figure 1 to Figure 4 By comparison, it can be seen that with the increase of calcination temperature, the acid neutralization capacity of FA complex gradually decreases, and the acid neutralization capacity of FO complex gradually increases. With the increase of the ratio of alkali slag and oyster shell powder, the acid neutralization capacity of the material gradually increases, but the rate of increase is highest between 1:1.5 and 2. With the increase of calcination temperature, the active K content in FA and FO complexes is increased, among which the activation effect of K with alkali slag is better, especially when the calcination temperature reaches 900°C. With the increase of the ratio of alkali slag, the activation amount of K first increases significantly and then gradually decreases. Taking into account the ratio of potassium feldspar to alkali slag and oyster shell powder and the activity and acid neutralization capacity of K at the calcination temperature, the applicant preliminarily proposed that FAO (1:1.5:1.5) ternary complex material be calcined at 900°C to prepare a new conditioning agent FAO 900 .FAO 900 Compared with the simple compound (FAO) of potassium feldspar (F), alkali residue (A) and oyster shell (O), the content of active K in the medium 0 ) increased by 30.64 times, the K activation rate reached 79.5%, and the acid neutralization capacity (ANC) increased significantly by 36.25%.

[0091] Study 1: Study the effects of the mass ratio of potassium feldspar, alkali residue, oyster shell powder and calcination temperature on the performance of multifunctional acidic soil conditioner

[0092] Control Example 1: Different from Example 1, a multifunctional acidic soil conditioner is prepared by mixing potassium feldspar, alkali residue and oyster shell powder in a mass ratio of 1:1.5:1.5 without calcination.

[0093] Comparative Example 2: Different from Example 1, potassium feldspar, alkali slag and oyster shell powder are mixed and added into a calcining furnace, and calcined at 500° C. for 2 h to obtain a mixture A.

[0094] Comparative Example 3: Different from Example 1, potassium feldspar, alkali slag and oyster shell powder are mixed and added into a calcining furnace, and calcined at 700° C. for 2 h to obtain a mixture A.

[0095] Table 1 Performance of the multifunctional acidic soil conditioner prepared in Examples 1 to 8 and Comparative Examples 1 to 3

[0096]

[0097] Conclusion: According to the data in Table 1 and Figure 1 , Figure 2It can be seen that the calcination temperature and the mixing ratio of potassium feldspar, alkali residue and oyster shell will affect the performance of the multifunctional acidic soil conditioner. Under the binary composite system of potassium feldspar and alkali residue, under the condition of constant calcination temperature, as the alkali residue ratio increases (that is, when the ratio of potassium feldspar to alkali residue is greater than 1:1.5), its acid neutralization capacity ANC increases slightly, but the active K content decreases rapidly. Further, from the data comparison of Control Example 1 and Examples 1 to 3, it can be seen that in the ternary composite material, as the relative proportion of potassium feldspar in the three raw materials decreases (that is, when the ratio of potassium feldspar to the total mass of alkali residue and oyster shell is less than 1:3), the alkaline substance increases slightly, while the active K content decreases slightly.

[0098] From the comparison between Example 1 and Examples 4 to 6, it can be seen that the conditioners prepared by adding water in Examples 4 to 6 can slightly increase the active K content, which can be further increased by about 10%, and under the pretreatment conditions of Example 5, the values ​​of active K content and ANC are both good. Therefore, in the actual preparation process, water immersion treatment is selected as a further optimization scheme;

[0099] From the data comparison of Example 1, Example 7 to Example 8 and Comparative Example 2 and Comparative Example 3, it can be obtained that when the mixing ratio is constant, the calcination temperature is calcined at 500°C and 700°C for 2h, which will also cause a decrease in the active K content and the acid neutralization capacity, and the active K content and the acid neutralization capacity are significantly improved at 900°C; therefore, considering the K activity and the acid neutralization capacity of potassium feldspar, alkali slag and oyster shell powder as well as the calcination temperature, the applicant selected FAO (1:1.5:1.5) ternary compound material calcined at 900°C as the optimal ratio and calcination temperature to prepare the new conditioning agent FAO 900 ; and by Fig.10 Available, pre-treated water (FAO 900 ) and without adding water (FAOW 900 ) showed significant differences in the active K content in the conditioners prepared by adding water. The conditioner prepared by adding water could slightly increase the active K content, which could be further increased by about 10%.

[0100] Study 2: Study the effect of the conditioner prepared in this application on improving soil acidity and increasing the content of effective K, Ca, and Mg in the soil

[0101] The conditioner prepared by the present invention was added to acidic soil with a pH of 3.8, and the final soil pH value, exchangeable acid, and effective K, Ca, and Mg contents were measured. The results are as follows: Figures 5 to 9 As shown;

[0102] in conclusion: Figures 5 to 9 The results showed that FAO 900 The effect of increasing soil pH ranks third among all tested materials, slightly lower than FO900 Its effect on reducing soil exchangeable acid is second only to O 900 , which is significantly better than the materials calcined by potassium feldspar and alkali slag alone or in combination, and is also significantly better than the commercial conditioning agent MTTBC, indicating that FAO 900 Can ensure the improvement effect on soil acidity; FAO 900 While significantly increasing the exchangeable K content of the soil, it effectively supplemented the exchangeable Ca 2+ and Mg 2+ .FAO 900 Exchangeable K + , Ca 2+ and Mg 2+ In terms of improving soil exchangeable K, FAO 900 The most significant difference was FA 900 Other modifiers are 40% to 85% higher than FO 900 , FAO 900 It can significantly increase the effective K and Mg content in the soil. 900 There is no such function. In summary, FAO 900 It has a significant effect on improving soil acidity and can effectively balance soil K + , Ca 2+ and Mg 2+ The content can significantly improve the soil fertility level, and its comprehensive performance in improving acidic soil is better than similar products.

[0103] Study 3: Study the effect of the addition ratio of potassium feldspar and alkali sedge straw on the effect of soil conditioner

[0104] Table 2 Effects of potassium feldspar and alkali sedge straw on the performance of soil conditioners at different addition ratios

[0105]

[0106] Conclusion: From the data in Table 2, it can be seen that the addition ratio of potassium feldspar, alkali sedge straw and alkali residue at 900℃ is 1:2:1.5, which can further increase the active K content of the improver. 900 The active K content in the Figures 5 to 9 In summary, although FA 900 It also significantly improves the soil exchangeability K + , but its exchangeable Ca 2+ and Mg 2+ The improvement effect is limited and the improvement effect on soil acidity is insufficient. Compared with FA 900 For FAO 900 It not only effectively increases the effective K and Ca content in the soil, but also significantly increases the effective Mg content.900 The available Mg content in soil cannot be provided, and FAO 900 The improvement effect on soil acidity is significantly better than FA 900 ;by FAO 900 Compared with the data of 1g potassium feldspar + 2g alkali stalk + 1.5g alkali residue, it can be found that replacing oyster shell powder with alkali stalk can slightly reduce its ANC, but can effectively increase the active K content in the material, thereby further improving the exchangeable K content in the soil. In summary, in actual applications, oyster shell powder or alkali stalk can be selected as the corresponding synergist according to needs.

[0107] Study 4: Study the effect of the addition of sepiolite and binder and the application method of soil conditioner on the effect of soil conditioner

[0108] Control Example 4: Different from Example 12, no ultrasonic assisted treatment was performed.

[0109] Comparative Example 5: The difference from Example 12 is that D-fructose 1,6-bisphosphate trisodium salt hydrate is replaced by chitosan.

[0110] Table 3 Performance of the multifunctional acidic soil conditioner prepared in Example 5, Example 9 to Example 18 and Comparative Example 4 to Comparative Example 5

[0111]

[0112] Conclusion: From the data of Example 5 and Example 9 to Example 11 in Table 3, it can be seen that the addition of sepiolite and a binder calcium wood sulfonate to granulate a soil conditioner and the application in the soil process will not lead to a decrease in the exchange performance of soil potassium, calcium and magnesium ions. The main reason is that the crystal structure of sepiolite gives it a large specific surface area and good adsorption performance, and has a significant adsorption effect on cations. This property enables sepiolite to effectively adsorb and passivate toxic cations such as Al in the soil in an acidic soil conditioner, reducing the risk of toxicity to crops; sepiolite also has a strong ion exchange capacity, heavy metal ion adsorption, and the ability to regulate soil ion balance, which enables it to more effectively regulate the ion balance in the soil during soil conditioning, improve soil fertility and nutrient absorption efficiency of crops; granulation is convenient for application operation, and considering the comprehensive economic point of view, Example 9 is selected as the optimal solution;

[0113] From the data comparison of Example 5 and Examples 12 to 18, it can be seen that in Examples 12 to 18, by loading the soil conditioner on the surface of the modified biochar under ultrasonic conditions before putting it into use, the effect of the acidic soil conditioner can be significantly improved on the basis of Example 5, and the ultrasonic treatment can improve the combination between the conditioner particles and the biochar, increase the adsorption capacity of the biochar, thereby improving the ability of the soil conditioner to retain fertilizer in the soil, and Example 12 has the best effect; and according to the data comparison of Examples 12 to 16 and Control Example 4, it can be seen that the lack of ultrasonic auxiliary treatment will cause the loading effect of the soil conditioner to be weakened, thereby reducing the combination between the soil particles and the biochar, weakening the adsorption capacity of the biochar, and further affecting the ability of the soil conditioner to retain nutrients in the soil; According to the data comparison of Examples 12, Examples 17 to 18 and Control Example 5, it can be seen that the KOH modification treatment further improves the effect of the conditioner on the improvement of the effective K in the soil, and supplements the soil K supply to plants; D-fructose 1,6-bisphosphate trisodium salt hydrate as a template can interact with biochar, promote the development of the microstructure inside the biochar, and form a multi-level pore structure, thereby enhancing its adsorption capacity for harmful substances in acidic soil and soil improvement effect, and also helps to maintain the effectiveness of the active ingredients in the conditioner, reduce their loss in the soil, thereby improving the acid-base balance and fertility of the soil. D-fructose 1,6-bisphosphate trisodium salt hydrate is replaced by chitosan, which can be slowly degraded into small molecular carbohydrates in the soil. This degradation process will change the surface properties of biochar, thereby affecting the loading stability of the soil conditioner. In addition, since chitosan itself is an adsorbent with good adsorption properties, this adsorption will compete with the active potassium, calcium and magnesium metal ions in the soil conditioner for adsorption, thereby affecting the exchangeability of these ions and reducing the effect of the acidic soil conditioner. Therefore, the soil conditioner prepared by Example 12 in this scheme has a better improvement effect on acidic soil.

Claims

1. A method for preparing a multifunctional acidic soil conditioner, characterized in that: The method comprises potassium feldspar, alkali residue and synergist, sepiolite and calcium lignosulfonate solution with a mass concentration of 4-6% in a mass ratio of 1:1.3-1.7:1-2:0.1-0.2:0.2-0.3; the synergist is alkali sedge straw or oyster shell powder; and the preparation method comprises the following steps: S1', preprocessing Grind potash feldspar powder, alkali residue powder and synergist with a particle size of less than 0.15 mm respectively, then mix the three to obtain a mixed powder, add clean water at a solid-liquid mass ratio of 1:1-2, soak and stir for 0.5-2h, then treat at a microwave power of 600-650W for 0.5-1h until the water content of the mixed powder is 8-10%, and obtain a material powder for standby use; S2', Preparation of soil conditioner The material powder is added into a calcining furnace and calcined at 850-950° C. for 1.5-2.5 hours to obtain a mixture; sepiolite is then added into the mixture for mixing, and after mixing, a calcium wood sulfonate solution is sprayed at a rate of 30-50 mL / min through a disc granulator, and the mixture is dried at a temperature of 45-50° C. to a water content of 4-6%, and then granulated and sieved to obtain particles with a particle size of 4-6 mm, which is a soil conditioner.

2. The application method of the multifunctional acidic soil conditioner prepared by the method according to claim 1, characterized in that: The following steps are involved: S1. Determine the acid buffer capacity of the soil to be treated, recorded as pHBC, in units of mmol / kg / pH; Determine the initial pH of the soil to be treated, recorded as pH ini ; Determine the acid neutralization capacity at the corresponding temperature, denoted as C, in mol / kg; denoted as pH the expected pH of the soil after treatment tar , the value is 5.0~6.0; S2. Then, the estimated field dosage M of the multifunctional acidic soil conditioner is calculated according to formula (1), in kg / mu; M=pHBC×[(pH tar -pH ini -0.1307) / 0.6346]×173.16 / C (1) S3. Calculate the estimated amount of potassium fertilizer KCl N based on the estimated field amount M of the acidic soil conditioner and formula (2), in kg / mu; N = (conventional potassium fertilizer K2O dosage - M × 0.021) × 149 / 94 (2) Among them, the dosage of conventional potassium fertilizer K2O is the amount of fertilizer that local farmers are accustomed to applying, and the general value is 7-10kg / mu; S4. Then, M kg / mu of multifunctional acidic soil conditioner and N kg / mu of potassium fertilizer are evenly applied to the soil to be treated, and the 0-20 cm surface soil is turned over to obtain treated soil, thereby achieving conditioning of the acidic soil.

3. The application method of a multifunctional acidic soil conditioner according to claim 2, characterized in that: The soil conditioner is loaded on the surface of the modified biochar and then put into use, wherein the loading amount of the soil conditioner is 50-70%; The loading method is as follows: adding a soil conditioner to water at a concentration ratio of 1 g: 8-12 mL, stirring and mixing to obtain a dispersion, then adding modified biochar at a ratio of 20 g: 240-360 mL of modified biochar: dispersion, and performing ultrasonic-assisted treatment. After the treatment, the modified biochar loaded with the soil conditioner is placed in a drying oven at 50-60° C. to dry, thereby obtaining modified biochar with the soil conditioner loaded on the surface; Among them, in the ultrasonic-assisted treatment process, the ultrasonic treatment time is 25 to 45 minutes, the ultrasonic frequency is 25 to 35 kHz, and the power is 80 to 100W.

4. The application method of a multifunctional acidic soil conditioner according to claim 3, characterized in that: The modified biochar is prepared as follows: 20 g of biochar is immersed in 50 mL of a KOH solution with a mass concentration of 50 to 100 g / L for surface treatment, the immersion time is 2 to 5 hours, stirring once every 1 hour during the immersion process, then 1.00 to 1.50 g of citric acid solid is weighed and slowly added into 25 mL of deionized water, after being completely dissolved, the citric acid solution is slowly added into the biochar suspension, mixed and placed in a water bath at 80 to 85° C. for heating and stirring for 2 hours, then 0.4 to 0.6 g of D-fructose 1,6-bisphosphate trisodium salt hydrate is dispersed in 25 mL of water, ultrasonically mixed, and then added dropwise into the biochar suspension, heated and stirred in a water bath for 30 to 50 minutes, and then dried in a drying oven at 50 to 60° C. to obtain the modified biochar.

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