Soil purifying agent and preparation method thereof

Abstract

The invention relates to the technical field of soil purification, in particular to a soil purifying agent and a preparation method thereof. The soil purifying agent is prepared from the following raw materials in parts by mass: 10 to 15 parts of desulfurized gypsum, 1 to 7 parts of perlite, 1 to 7 parts of vermiculite, 1 to 7 parts of montmorillonite, 1 to 7 parts of limestone, 1 to 7 parts of dolomite, 1 to 7 parts of diatomite, 1 to 7 parts of bentonite, 1 to 7 parts of attapulgite, 1 to 7 parts of zeolite, 1 to 7 parts of illite, 1 to 7 parts of medical stone and 20 to 25 parts of a nano composite material, the invention discloses a soil purifying agent and a preparation method thereof.The prepared soil purifying agent can adjust the pH value of soil, make the soil loose and not hardened, improve the water retention effect of the soil and make crop roots free of bacteria, meanwhile, the prepared soil purifying agent adsorbs elements such as nitrogen, phosphorus and potassium, and the soil purifying agent has the advantages that the soil purifying agent is environmentally friendly and has a good application prospect. The growth environment of crops is improved, and the emergence rate and yield are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil purification, and in particular to a soil purification agent and a preparation method thereof. BACKGROUND

[0002] Soil, as the core carrier of the terrestrial ecosystem and the basic resource of agricultural production, its health status directly affects crop yield, agricultural product safety and ecological environment sustainability. In recent years, with the excessive use of pesticides and fertilizers, the penetration of industrial waste and the aggravation of continuous cropping obstacles, soil pollution, compaction degradation, fertility decline and frequent soil-borne disease problems have become increasingly prominent, which seriously restricts the development of modern agriculture. Under this background, as a key technical means to repair degraded soil, soil purification agent has played a role in pollution control, but the existing products generally have the defects of single function and poor synergy, which is difficult to meet the comprehensive demand.

[0003] Therefore, it has become a technical problem to be solved in the current agricultural technology field to develop a soil purification agent which can adjust the pH value of soil, make the soil loose and not compacted, improve the water retention effect of soil and enhance the disease resistance of crops. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a soil purification agent and a preparation method thereof.

[0005] In a first aspect, the present application provides a soil purification agent, which adopts the following technical solution: A soil purification agent, comprising the following raw materials in parts by mass: desulfurized gypsum 10-15 parts, perlite 1-7 parts, vermiculite 1-7 parts, montmorillonite 1-7 parts, limestone 1-7 parts, dolomite 1-7 parts, diatomite 1-7 parts, bentonite 1-7 parts, attapulgite 1-7 parts, zeolite 1-7 parts, illite 1-7 parts, medical stone 1-7 parts and nano composite material 20-25 parts.

[0006] By adopting the above technical solution, in the present application, the raw materials are improved by adding natural active minerals such as perlite, vermiculite, montmorillonite, limestone, dolomite, diatomite, bentonite, attapulgite, zeolite, illite and medical stone. The added natural active minerals have environmental protection and sustainability, and have a comprehensive improvement effect on soil structure and fertility. The added natural active minerals adjust the air permeability, water retention, pH value and nutrient availability of soil through physical adsorption, chemical neutralization and ion exchange mechanisms, so that the soil is loose and not compacted, thereby improving soil fertility and crop growing environment and enhancing the disease resistance of crops.

[0007] In the present application, the desulfurized gypsum added by improving the raw materials can reduce the alkalinity of soil.

[0008] Preferably, the nanocomposite comprises the following raw materials in mass fraction: 3-8 parts of chitosan, 0.3-0.8 parts of cellulase, 2-6 parts of cumengite and 1-2 parts of surfactant.

[0009] Preferably, the surfactant is a cationic surfactant.

[0010] By adopting the technical scheme, the chitooligosaccharide and the cumengite are used as raw materials to synthesize the nanocomposite containing chitooligosaccharide and cumengite, the nanocomposite is added to the soil purifying agent, and the performance of the soil purifying agent is further improved through the synergistic effect between the nanocomposite and other raw materials.

[0011] The soil purifying agent containing the nanocomposite can effectively improve the soil physical structure, enhance the water and fertilizer retention capacity, adjust the soil chemical properties, optimize the nutrient availability, make the soil loose and not compacted, improve the soil ecology, enhance the long-term effectiveness of soil fertility, and enhance the disease resistance of crops.

[0012] Preferably, the preparation method of the nanocomposite comprises the following steps: The chitosan and the cellulase are mixed to obtain chitooligosaccharide; The cumengite and the surfactant are mixed to obtain organic cumengite; The chitooligosaccharide and the organic cumengite are mixed to obtain the nanocomposite.

[0013] By adopting the technical scheme, the cumengite is modified by using the surfactant, and the chitooligosaccharide is strengthened by using the organic cumengite to obtain the nanocomposite with excellent comprehensive performance, the nanocomposite is added to the soil purifying agent, and the comprehensive performance of the soil purifying agent is further improved through the synergistic effect between the nanocomposite and other raw materials.

[0014] Preferably, the soil purifying agent further comprises 30-40 parts of modified chitooligosaccharide complex.

[0015] Preferably, the modified chitooligosaccharide complex comprises the following raw materials in mass fraction: 100-120 parts of attapulgite, 5-15 parts of zinc oxide, 2-15 parts of glyceryl laurate, 4-13 parts of chitooligosaccharide, 1-3 parts of silane coupling agent and 0.5-2 parts of glutaraldehyde.

[0016] Preferably, the preparation method of the modified chitooligosaccharide complex comprises the following steps: The attapulgite is acidified by using an acid; After the acidified attapulgite is mixed with the silane coupling agent, the pH is adjusted to be acidic, the chitooligosaccharide and the zinc oxide are added and mixed, the glyceryl laurate is added and mixed, and then the glutaraldehyde is added and mixed to obtain the modified chitooligosaccharide complex.

[0017] Preferably, when the acid is used to acidize the attapulgite, the mass-volume ratio of the attapulgite to the acid is 1:(5-10).

[0018] Preferably, the pH is adjusted to 3-5.

[0019] By using the technical solution described above, in the present application, attapulgite is used as the core carrier, the active sites are activated through surface modification, the surface charge is adjusted to enhance the adsorption capacity of zinc oxide and chitosan oligosaccharide, and then the zinc oxide and chitosan oligosaccharide are loaded on the surface of the attapulgite through physical / chemical action, and finally the composite structure is stabilized through surface crosslinking to prepare the modified chitosan oligosaccharide composite.

[0020] The modified chitosan oligosaccharide composite is added to the soil purifying agent, and the performance of the soil purifying agent is further improved through the synergistic effect between the modified chitosan oligosaccharide composite and other raw materials. The use of the soil purifying agent containing the modified chitosan oligosaccharide composite can effectively improve the utilization rate of the soil purifying agent, improve the soil structure, balance the chemical properties of the soil, enhance the microbial activity, enhance the disease resistance of crops, and make the soil loose and not compacted.

[0021] In the second aspect, the present application provides a preparation method of a soil purifying agent, which uses the following technical solution: A preparation method of a soil purifying agent, the steps of the preparation method are as follows: The raw materials are weighed according to the formula; The desulfurized gypsum, perlite, vermiculite, montmorillonite, limestone, dolomite, diatomite, bentonite, attapulgite, zeolite, illite, medical stone, nanocomposite, and modified chitosan oligosaccharide composite are mixed and dried to obtain the soil purifying agent.

[0022] By using the technical solution described above, in the present application, the raw materials of the soil purifying agent are improved, and the soil purifying agent is prepared through the synergistic effect between the components. When the soil purifying agent is applied, the soil physical structure can be effectively improved, the water and fertilizer retention capacity can be enhanced, the soil chemical properties can be adjusted, the nutrient availability can be optimized, the soil ecology can be improved, and the long-term effectiveness of soil fertility can be enhanced.

[0023] In summary, the present application has at least one of the following beneficial technical effects: The present application discloses a soil purifying agent and a preparation method thereof. The soil purifying agent prepared by the present application can effectively adjust the pH of the soil, make the soil loose and not compacted, improve the growth environment of crops, effectively improve the disease resistance of crops, and improve the water retention effect of the soil. DETAILED DESCRIPTION

[0024] The technical solutions of this application are further illustrated by specific embodiments below. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0025] All raw materials involved in this application are commercially available products, among which, Chitosan, with a degree of deacetylation of 90% and a weight-average molecular weight of 2.5 × 10⁻⁶. 5 Purchased from Sinopharm Chemical Reagent Co., Ltd.; cellulase purchased from Shanghai Lanji Technology Development Co., Ltd. Ratoxite, calcium-based raptoxite, with a cation exchange capacity of 45 mmol / 100g, was purchased from Hubei Mingliu Ratoxite Technology Co., Ltd. Surfactant, Gemini Surfactant 18-3-18, purchased from Henan Daochun Chemical Technology Co., Ltd.; Attapulgite, Jiangsu Huixin Attapulgite Co., Ltd.; Glyceryl lauryl ester, 1-lauroyl-racemic-glycerol, purchased from Merck; Chitosan oligosaccharide, CAS No. 148411-57-8, Qingdao Bozhi Huili Biotechnology Co., Ltd.; Desulfurized gypsum was purchased from Lingshou Runming Mineral Products Co., Ltd. The present application will be further described in detail below with reference to embodiments and comparative examples.

[0026] Preparation Example 1: Preparation of nanocomposite materials: The nanocomposite material includes the following raw materials: 5 kg chitosan, 0.5 kg cellulase, 4 kg attapulgite, and 1.5 kg surfactant.

[0027] The surfactant is Gemini surfactant 18-3-18.

[0028] The preparation method of nanocomposite materials includes the following steps: Cellulase, water, and acetic acid were mixed to obtain a 0.8% (w / w) aqueous solution of cellulase. Chitosan and cellulase aqueous solution were enzymatically hydrolyzed at 45°C for 2.5 hours, centrifuged, and washed successively with anhydrous ethanol and deionized water to obtain chitosan oligosaccharide; chitosan oligosaccharide was added to water to obtain a 1% (w / w) chitosan oligosaccharide aqueous solution. Add rapasite to water to obtain a suspension with a mass fraction of 2%, allow it to swell for 50 hours, place it in a microwave radiation instrument, set the microwave radiation power to 800W and the radiation temperature to 80℃, and obtain a rapasite suspension. The surfactant is dissolved in 100 mL of isopropyl alcohol (50% by volume) and added dropwise to the attapulgite suspension under microwave radiation. After microwave reaction for 1 hour, centrifugal separation is performed, and the organic attapulgite is obtained by washing with isopropyl alcohol (50% by volume). The organic attapulgite is added to water to obtain a 1% by mass organic attapulgite suspension. The organic attapulgite suspension is placed in a microwave radiation instrument, and chitosan oligosaccharide aqueous solution is added dropwise to the organic attapulgite suspension under the conditions of 800 W and 85°C. Microwave reaction is performed for 85 minutes, and the nanocomposite is obtained by freeze-drying after the reaction.

[0029] Preparation Example 2 Preparation of the nanocomposite The nanocomposite comprises the following raw materials: chitosan 3 kg, cellulase 0.3 kg, attapulgite 2 kg, and surfactant 1 kg.

[0030] The surfactant is Gemini surfactant 18-3-18.

[0031] The preparation method of the nanocomposite comprises the following steps: The cellulase, water, and acetic acid are mixed to obtain a 0.8% by mass cellulase aqueous solution. The chitosan and the cellulase aqueous solution are subjected to enzymatic hydrolysis at 45°C for 2.5 hours, centrifugal separation is performed, and the chitosan oligosaccharide is obtained by washing with anhydrous ethanol and deionized water in sequence. The chitosan oligosaccharide is added to water to obtain a 1% by mass chitosan oligosaccharide aqueous solution. The attapulgite is added to water to obtain a 2% by mass suspension, and swelling is performed for 50 hours. The attapulgite suspension is obtained by placing it in a microwave radiation instrument and setting the microwave radiation power to 800 W and the radiation temperature to 80°C. The surfactant is dissolved in 100 mL of isopropyl alcohol (50% by volume) and added dropwise to the attapulgite suspension under microwave radiation. After microwave reaction for 1 hour, centrifugal separation is performed, and the organic attapulgite is obtained by washing with isopropyl alcohol (50% by volume). The organic attapulgite is added to water to obtain a 1% by mass organic attapulgite suspension. The organic attapulgite suspension is placed in a microwave radiation instrument, and chitosan oligosaccharide aqueous solution is added dropwise to the organic attapulgite suspension under the conditions of 800 W and 85°C. Microwave reaction is performed for 85 minutes, and the nanocomposite is obtained by freeze-drying after the reaction.

[0032] Preparation Example 3 Preparation of the nanocomposite The nanocomposite comprises the following raw materials: chitosan 8 kg, cellulase 0.8 kg, attapulgite 6 kg, and surfactant 2 kg.

[0033] The surfactant is Gemini surfactant 18-3-18.

[0034] The preparation method of the nanocomposite is as follows: The cellulase, water and acetic acid are mixed to obtain a cellulase aqueous solution with a mass concentration of 0.8%; The chitosan and the cellulase aqueous solution are subjected to enzymolysis at 45°C for 2.5 hours, centrifuged, and sequentially washed with anhydrous ethanol and deionized water to obtain chitooligosaccharide; the chitooligosaccharide is added to water to obtain a chitooligosaccharide aqueous solution with a mass fraction of 1%; The luctite is added to water to obtain a suspension with a mass fraction of 2%, and is subjected to swelling for 50 hours; the luctite suspension is placed in a microwave irradiation instrument, a microwave irradiation power of 800 W is set, and a radiation temperature of 80°C is set to obtain the luctite suspension; The surfactant is dissolved in 100 mL of isopropyl alcohol (50% by volume), and is added dropwise to the luctite suspension under microwave irradiation; after microwave reaction for 1 hour, centrifugation is performed, and the luctite is washed with isopropyl alcohol (50% by volume) to obtain organic luctite; the organic luctite is added to water to obtain an organic luctite suspension with a mass fraction of 1%; The organic luctite suspension is placed in a microwave irradiation instrument, the chitooligosaccharide aqueous solution is added dropwise to the organic luctite suspension under conditions of 800 W and 85°C, microwave reaction is performed for 85 minutes, and after the reaction, freeze-drying is performed to obtain the nanocomposite.

[0035] Preparation Example 4: Preparation of the modified chitooligosaccharide complex: The modified chitooligosaccharide complex comprises the following raw materials: 110 kg of attapulgite, 10 kg of zinc oxide, 8 kg of glyceryl laurate, 9 kg of chitooligosaccharide, 2 kg of silane coupling agent, and 0.9 kg of glutaraldehyde.

[0036] The preparation method of the modified chitooligosaccharide complex is as follows: The attapulgite is crushed to 100 mesh, and the attapulgite is placed in dilute hydrochloric acid with a concentration of 2 mol / L; after acid immersion treatment at 70°C for 3 hours, filtration is performed; the mass-volume ratio of the attapulgite to the acid is 1:7; The attapulgite after acid immersion treatment is washed with deionized water until neutral, and the silane coupling agent KH-550 is added; after stirring at 70°C for 3 hours, vacuum drying is performed at 100°C for 4 hours to remove water, to obtain the activated attapulgite; The activated attapulgite is dispersed in 100 mL of deionized water, and the pH is adjusted to 4 with dilute hydrochloric acid (1 mol / L) to obtain an attapulgite solution; The chitooligosaccharide is dissolved in water to obtain a chitooligosaccharide aqueous solution with a mass fraction of 2%; The zinc oxide is dispersed in the chitosan aqueous solution, glacial acetic acid is added to adjust the pH to 4, after stirring for 1 hour, the attapulgite solution is added, stirring is performed for 2 hours, then centrifugal separation is performed, washing is performed with deionized water, and drying is performed at 40°C for 20 min to obtain a composite carrier; the composite carrier is mixed with glyceryl laurate for 20 min, then glutaraldehyde is added and mixed for 2 hours, and then filtration is performed to obtain the modified chitosan composite.

[0037] Preparation Example 5: Preparation of the modified chitosan composite: The modified chitosan composite comprises the following raw materials: 100 kg of attapulgite, 5 kg of zinc oxide, 2 kg of glyceryl laurate, 4 kg of chitosan, 1 kg of silane coupling agent, and 0.5 kg of glutaraldehyde.

[0038] The preparation method of the modified chitosan composite comprises the following steps: The attapulgite is crushed to 100 mesh, and the attapulgite is placed into dilute hydrochloric acid with a concentration of 2 mol / L, and then acid immersion treatment is performed at 70°C for 3 hours, followed by filtration; the mass-volume ratio of the attapulgite to the acid is 1:5; The attapulgite after the acid immersion treatment is washed with deionized water until neutral, and then the silane coupling agent KH-550 is added, stirring is performed at 70°C for 3 hours, and then vacuum drying is performed at 100°C for 4 hours to remove water, thereby obtaining the activated attapulgite; The activated attapulgite is dispersed in 100 mL of deionized water, and dilute hydrochloric acid (1 mol / L) is used to adjust the pH to 4, thereby obtaining the attapulgite solution; The chitosan is dissolved in water to obtain a 2 wt% chitosan aqueous solution; The zinc oxide is dispersed in the chitosan aqueous solution, glacial acetic acid is added to adjust the pH to 4, after stirring for 1 hour, the attapulgite solution is added, stirring is performed for 2 hours, then centrifugal separation is performed, washing is performed with deionized water, and drying is performed at 40°C for 20 min to obtain a composite carrier; the composite carrier is mixed with glyceryl laurate for 20 min, then glutaraldehyde is added and mixed for 2 hours, and then filtration is performed to obtain the modified chitosan composite.

[0039] Preparation Example 6: Preparation of the modified chitosan composite: The modified chitosan composite comprises the following raw materials: 120 kg of attapulgite, 15 kg of zinc oxide, 15 kg of glyceryl laurate, 13 kg of chitosan, 3 kg of silane coupling agent, and 2 kg of glutaraldehyde.

[0040] The preparation method of the modified chitosan composite comprises the following steps: The attapulgite is crushed to 100 mesh, and the attapulgite is put into dilute hydrochloric acid with a concentration of 2 mol / L, and then filtered after acid immersion treatment at 70℃ for 3 hours; the mass-volume ratio of the attapulgite to the acid is 1:10; The attapulgite after acid immersion treatment is washed with deionized water until neutral, and then silane coupling agent KH-550 is added, and then stirred at 70℃ for 3 hours, and then vacuum dried at 100℃ for 4 hours to remove water, so as to obtain activated attapulgite; The activated attapulgite is dispersed in 100 mL of deionized water, and then diluted hydrochloric acid (1 mol / L) is used to adjust the pH to 4, so as to obtain an attapulgite solution; Chitosan oligosaccharide is dissolved in water to obtain a 2wt% chitosan oligosaccharide aqueous solution; Zinc oxide is dispersed in the chitosan oligosaccharide aqueous solution, and glacial acetic acid is added to adjust the pH to 4, and then stirred for 1 hour, and then the attapulgite solution is added, and then stirred for 2 hours, and then centrifuged, and then washed with deionized water, and then dried at 40℃ for 20 min, so as to obtain a composite carrier; the composite carrier is mixed with glyceryl laurate for 20 min, and then glutaraldehyde is added and mixed for 2 hours, and then filtered, so as to obtain a modified chitosan oligosaccharide composite.

[0041] Example 1: A soil purifying agent, comprising the following raw materials: desulfurized gypsum 13 kg, perlite 4 kg, vermiculite 4 kg, montmorillonite 4 kg, limestone 4 kg, dolomite 4 kg, diatomite 4 kg, bentonite 4 kg, attapulgite 4 kg, zeolite 4 kg, illite 4 kg, medical stone 4 kg, nanocomposite 23 kg, and modified chitosan oligosaccharide composite 35 kg.

[0042] The nanocomposite is prepared by the preparation example 1.

[0043] The modified chitosan oligosaccharide composite is prepared by the preparation example 4.

[0044] A preparation method of a soil purifying agent, and the preparation method comprises the following steps: (1) Pretreatment of raw materials: The perlite, montmorillonite, dolomite, diatomite, bentonite, attapulgite, zeolite, illite, and medical stone are put into dilute hydrochloric acid with a concentration of 3 mol / L (the mass-volume ratio of the solid to the dilute hydrochloric acid is 1:10), and then filtered after acid immersion treatment at 70℃ for 4 hours, and then washed with deionized water until neutral, and then dried, and then crushed to 0.5-2 mm particles; The vermiculite is calcined at 800℃ for 30 min, and then crushed to 0.5-2 mm particles; The limestone is calcined at 1000℃ for 3 h, and then crushed to 0.5-2 mm particles; (2) Preparation of the soil purifying agent The perlite, vermiculite, montmorillonite, limestone, dolomite, diatomite, bentonite, attapulgite, zeolite, illite, and medical stone treated by the above steps are mixed with desulfurization gypsum, nanocomposite, and modified chitosan oligosaccharide compound, 30 kg of deionized water is added, stirred at 40℃ for 40 min, dried and crushed to obtain the soil purification agent.

[0045] Example 2: A soil purification agent includes the following raw materials: desulfurization gypsum 10 kg, perlite 1 kg, vermiculite 1 kg, montmorillonite 1 kg, limestone 1 kg, dolomite 1 kg, diatomite 1 kg, bentonite 1 kg, attapulgite 1 kg, zeolite 1 kg, illite 1 kg, medical stone 1 kg, nanocomposite 20 kg, and modified chitosan oligosaccharide compound 30 kg.

[0046] The nanocomposite is prepared by Preparation Example 2.

[0047] The modified chitosan oligosaccharide compound is prepared by Preparation Example 5.

[0048] A preparation method of a soil purification agent includes the following steps: (1) Pretreatment of raw materials: The perlite, montmorillonite, dolomite, diatomite, bentonite, attapulgite, zeolite, illite, and medical stone are put into dilute hydrochloric acid with a concentration of 3 mol / L (mass-volume ratio of solid to dilute hydrochloric acid is 1:10), and then subjected to acid immersion treatment at 70℃ for 4 hours, filtered, washed with deionized water until neutral, dried, and crushed to 0.5-2 mm particles; The vermiculite is calcined at 800℃ for 30 min, and crushed to 0.5-2 mm particles; The limestone is calcined at 1000℃ for 3 h, and crushed to 0.5-2 mm particles; (2) Preparation of soil purification agent The perlite, vermiculite, montmorillonite, limestone, dolomite, diatomite, bentonite, attapulgite, zeolite, illite, and medical stone treated by the above steps are mixed with desulfurization gypsum, nanocomposite, and modified chitosan oligosaccharide compound, 30 kg of deionized water is added, stirred at 40℃ for 40 min, dried and crushed to obtain the soil purification agent.

[0049] Example 3: A soil purification agent includes the following raw materials: desulfurization gypsum 15 kg, perlite 7 kg, vermiculite 7 kg, montmorillonite 7 kg, limestone 7 kg, dolomite 7 kg, diatomite 7 kg, bentonite 7 kg, attapulgite 7 kg, zeolite 7 kg, illite 7 kg, medical stone 7 kg, nanocomposite 25 kg, and modified chitosan oligosaccharide compound 40 kg. The nanocomposite was prepared according to Preparation Example 3.

[0050] The modified chitooligosaccharide complex was prepared according to Preparation Example 6.

[0051] A preparation method of a soil purifying agent, the preparation method comprising the following steps: (1) Pretreatment of raw materials: The perlite, montmorillonite, dolomite, diatomite, bentonite, attapulgite, zeolite, illite, and medical stone were placed into dilute hydrochloric acid with a concentration of 3 mol / L (mass-volume ratio of solid to dilute hydrochloric acid was 1:10), and subjected to acid immersion treatment at 70°C for 4 hours, followed by filtration, washing with deionized water until neutral, drying, and crushing to 0.5-2 mm particles; The vermiculite was calcined at 800°C for 30 min, and crushed to 0.5-2 mm particles; The limestone was calcined at 1000°C for 3 h, and crushed to 0.5-2 mm particles; (2) Preparation of the soil purifying agent The perlite, vermiculite, montmorillonite, limestone, dolomite, diatomite, bentonite, attapulgite, zeolite, illite, and medical stone treated according to the above steps were mixed with desulfurization gypsum, nanocomposite, and modified chitooligosaccharide complex, and 30 kg of deionized water was added, followed by stirring at 40°C for 40 min, drying and crushing to obtain the soil purifying agent.

[0052] Example 4: The difference from Example 1 is that the amount of nanocomposite added is 20 kg.

[0053] Example 5: The difference from Example 1 is that the amount of nanocomposite added is 25 kg.

[0054] Example 6: The difference from Example 1 is that the amount of modified chitooligosaccharide complex added is 30 kg.

[0055] Example 7: The difference from Example 1 is that the amount of modified chitooligosaccharide complex added is 40 kg.

[0056] Comparative Example 1: The difference from Example 1 is that no nanocomposite is added.

[0057] Comparative Example 2: The difference from Example 1 is that no modified chitooligosaccharide complex is added.

[0058] Comparative Example 3: The difference from Example 1 is that the amount of nanocomposite added is 19 kg.

[0059] Comparative Example 4: The difference from Example 1 is that the amount of the nano-composite added is 26 kg.

[0060] Comparative Example 5: The difference from Example 1 is that the amount of the modified chitooligosaccharide complex added is 29 kg.

[0061] Comparative Example 6: The difference from Example 1 is that the amount of the modified chitooligosaccharide complex added is 41 kg.

[0062] Performance detection: 1. Soil basic physical and chemical property detection The soil purifying agent prepared by the above examples and comparative examples is applied to the same soil with hardened and salinized soil before and after application, and the soil is divided into non-interacting areas. According to the conventional management, 5 months later, the soil hardening and salinization are detected.

[0063] The soil hardening is measured by using a GPS soil tightness tester, model TJSD-750-II, and the measurement depth is 20 cm. The soil hardening is verified by the soil tightness.

[0064] Table 1 Soil hardening and salinization before and after application of soil purifying agent As shown in Table 1, the blank control group has high soil alkalinity and low organic matter content, which is not suitable for general crop growth. After the soil purifying agent prepared by the method of the present application is applied to the soil, the soil pH is reduced and the soil is loose and not hardened. It is shown that the application of the soil purifying agent of the present application can effectively improve the condition of the saline-alkali soil, effectively reduce the soil pH, and make the soil loose and not hardened.

[0065] According to the detection results of Example 1 and Comparative Example 1, the pH of the soil and the soil hardening detection results of Example 1 are better than those of Comparative Example 1, which shows that the addition of the nano-composite can effectively reduce the soil pH and make the soil loose and not hardened.

[0066] According to the detection results of Example 1 and Comparative Example 2, the pH of the soil and the soil hardening detection results of Example 1 are better than those of Comparative Example 2, which shows that the addition of the modified chitooligosaccharide complex can effectively reduce the soil pH and make the soil loose and not hardened.

[0067] From the test results of Example 1, Example 4, Example 5, Comparative Example 3, Comparative Example 4, it can be seen that the addition amount of the nano-composite material has certain influence on the pH of the soil and the soil hardening condition, and the effect is best when the addition amount of the nano-composite material is 20-25 kg.

[0068] From the test results of Example 1, Example 6, Example 7, Comparative Example 5, Comparative Example 6, it can be seen that the addition amount of the modified chitooligosaccharide complex has certain influence on the pH of the soil and the soil hardening condition, and the effect is best when the addition amount of the modified chitooligosaccharide complex is 30-40 kg.

[0069] 2. Determination of plant root rot incidence, emergence rate and yield The improver prepared in the examples and comparative examples was applied to the planting land to adjust and improve the soil of the planting land, 5 kg of soil purifying agent product was doped in every 100 kg of planting soil, and no any conditioner was doped as a blank group, and only base fertilizer was added as a control group. The sunlight greenhouse of the continuous cropping cucumber was planted, and the root rot incidence and underground pest occurrence of the plants in each group, the emergence rate and the yield were determined, and the results were as follows.

[0070] Table 2 test results According to the results in Table 2, it can be seen that the soil purifying agent prepared by the method of the application has high emergence rate and yield, low root rot incidence and less underground pest occurrence, which shows that the soil purifying agent of the application provides suitable nutrients for the growth of cucumber and also has significant disease and pest resistance.

[0071] From the test results of Example 1 and Comparative Example 1, it can be seen that the emergence rate, yield, root rot incidence and underground pest occurrence of Example 1 are better than those of Comparative Example 1, which shows that the addition of the nano-composite material can effectively improve the emergence rate and yield, and reduce the root rot incidence and underground pest occurrence.

[0072] From the test results of Example 1 and Comparative Example 2, it can be seen that the emergence rate, yield, root rot incidence and underground pest occurrence of Example 1 are better than those of Comparative Example 2, which shows that the addition of the modified chitooligosaccharide complex can effectively improve the emergence rate and yield, and reduce the root rot incidence and underground pest occurrence.

[0073] From the test results of Example 1, Example 4, Example 5, Comparative Example 3, Comparative Example 4, it can be seen that the addition amount of the nano-composite material has certain influence on the emergence rate, yield, root rot incidence and underground pest occurrence, and the effect is best when the addition amount of the nano-composite material is 20-25 kg.

[0074] From the test results of Example 1, Example 6, Example 7, Comparative Example 5, and Comparative Example 6, it can be seen that the addition amount of the modified chitooligosaccharide compound has certain influence on the emergence rate, yield, root rot incidence, and occurrence of underground pests, and the effect is best when the addition amount of the modified chitooligosaccharide compound is 30-40 kg.

[0075] 3. Water retention performance test The soil purifying agent prepared in the above examples and comparative examples was mixed with dry soil at a proportion of 0.35 wt%, placed in a PVC tube with a diameter of 5 cm and a length of 15.5 cm, the bottom of the tube was sealed with a nylon mesh and weighed, then the PVC tube was suspended in deionized water for 12 h, the tube was taken out and vertically hung on a rack, and the water was allowed to flow freely, and the weight of the tube was measured, and the maximum water retention rate was calculated.

[0076] The maximum water retention rate = (the total weight of the tube after no more water seepage - the weight of the dry soil and the PVC tube before wetting) / (the weight of the dry soil and the PVC tube before wetting - the weight of the PVC tube) x 100%.

[0077] Table 3 Water retention performance test Maximum water holding capacity (%) Blank control 22.5 Example 1 49.2 Example 2 46.1 Example 3 46.4 Example 4 47.2 Example 5 47.3 Example 6 48.5 Example 7 48.4 Comparative Example 1 35.1 Comparative Example 2 33.4 Comparative Example 3 42.9 Comparative Example 4 42.2 Comparative Example 5 40.8 Comparative Example 6 40.1 From the results in Table 3, it can be seen that the soil purifying agent prepared by the method of the present application has good water retention effect on soil.

[0078] From the test results of Example 1 and Comparative Example 1, it can be seen that the water retention rate of Example 1 is better than that of Comparative Example 1, which shows that the addition of the nano-composite material can effectively improve the water retention effect of the soil.

[0079] From the test results of Example 1 and Comparative Example 2, it can be seen that the water retention rate of Example 1 is better than that of Comparative Example 2, which shows that the addition of the modified chitooligosaccharide compound can effectively improve the water retention effect of the soil.

[0080] From the test results of Example 1, Example 4, Example 5, Comparative Example 3, and Comparative Example 4, it can be seen that the addition amount of the nano-composite material has certain influence on the water retention rate of the soil, and the effect is best when the addition amount of the nano-composite material is 20-25 kg.

[0081] From the test results of Example 1, Example 6, Example 7, Comparative Example 5, and Comparative Example 6, it can be seen that the addition amount of the modified chitooligosaccharide compound has certain influence on the water retention rate of the soil, and the effect is best when the addition amount of the modified chitooligosaccharide compound is 30-40 kg.

Claims

1. A soil decontaminant, characterized in that, The soil purifying agent comprises the following raw materials in mass fraction: desulfurization gypsum 10-15 parts, perlite 1-7 parts, vermiculite 1-7 parts, montmorillonite 1-7 parts, limestone 1-7 parts, dolomite 1-7 parts, diatomite 1-7 parts, bentonite 1-7 parts, attapulgite 1-7 parts, zeolite 1-7 parts, illite 1-7 parts, medical stone 1-7 parts, and nano composite material 20-25 parts.

2. A soil remediation agent according to claim 1, characterised in that: The nano composite material comprises the following raw materials in mass fraction: chitosan 3-8 parts, cellulase 0.3-0.8 parts, lectorite 2-6 parts, and surfactant 1-2 parts.

3. A soil remediation agent according to claim 2, characterised in that: The surfactant is a cationic surfactant.

4. A soil remediation agent according to claim 2, characterised in that: The preparation method of the nano composite material comprises the following steps: The chitosan and the cellulase are mixed to obtain chitooligosaccharide; The lectorite and the surfactant are mixed to obtain organic lectorite; The chitooligosaccharide and the organic lectorite are mixed to obtain the nano composite material.

5. The soil remediation agent of claim 1, wherein: The soil purifying agent further comprises modified chitooligosaccharide compound 30-40 parts.

6. A soil remediation agent according to claim 5, characterised in that: The modified chitooligosaccharide compound comprises the following raw materials in mass fraction: attapulgite 100-120 parts, zinc oxide 5-15 parts, glyceryl laurate 2-15 parts, chitooligosaccharide 4-13 parts, silane coupling agent 1-3 parts, and glutaraldehyde 0.5-2 parts.

7. A soil remediation agent according to claim 6, characterised in that: The preparation method of the modified chitooligosaccharide compound comprises the following steps: The attapulgite is acidified by using an acid; After the acidified attapulgite and the silane coupling agent are mixed, the pH is adjusted to be acidic, the chitooligosaccharide and the zinc oxide are added and mixed, the glyceryl laurate is added and mixed, and then the glutaraldehyde is added and mixed to obtain the modified chitooligosaccharide compound.

8. A soil remediation agent according to claim 7, characterised in that: When the attapulgite is acidified by using an acid, the mass-volume ratio of the attapulgite to the acid is 1: (5-10).

9. A soil remediation agent according to claim 7, wherein: The pH is adjusted to be 3-5.

10. A method for preparing the soil amendment according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: The raw materials are weighed according to the formula; The desulfurization gypsum, the perlite, the vermiculite, the montmorillonite, the limestone, the dolomite, the diatomite, the bentonite, the attapulgite, the zeolite, the illite, the medical stone, the nano composite material, and the modified chitooligosaccharide compound are mixed and dried to obtain the soil purifying agent.

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