A saline-alkali soil conditioner and a preparation method thereof

Abstract

The application discloses a novel saline-alkali soil conditioner and a preparation method thereof, and belongs to the technical field of soil remediation. The soil conditioner is prepared from the following raw materials in parts by weight: modified chitosan 10-20 parts, rice husk carbon 20-30 parts, gamma-aminobutyric acid 3-6 parts, polyacrylamide 1-5 parts, activator 1-3 parts, humic acid 20-40 parts, blast furnace slag 10-20 parts and compound microbial agent 1-3 parts. The modified chitosan used in the soil conditioner can effectively improve the physicochemical properties of soil and jointly act with the compound microbial agent of the application, so that the soil biological activity is increased. The special network and pore structure of the modified chitosan can provide a suitable ecological environment for microorganisms in the soil, promote the growth of various beneficial microorganisms, reduce the number of harmful microorganisms, promote the growth of crops, improve the yield and disease resistance of crops, and truly realize the improvement and full utilization of saline-alkali soil.

Description

TECHNICAL FIELD

[0001] The present application relates to a saline-alkali soil conditioner and a preparation method thereof, and belongs to the technical field of soil improvement. BACKGROUND

[0002] Soil salinization is a soil degradation process in which easily soluble salts in soil or groundwater accumulate in large quantities on the soil surface, and is one of the important problems that limit agricultural production development and threaten ecological environment safety. When the salt content of the soil surface exceeds 0.3%, the yield of crops will decrease significantly; when the salt content of the soil surface exceeds 0.6%, most plants cannot grow; and when the salt content of the soil surface exceeds 1.0%, only some special plants adapted to saline soil can grow. At present, soil salinization is still on the rise worldwide, and more than 100 countries have been affected by soil salinization, with a saline-alkali land area of 1.1 x 10 9 hm 2 , which greatly limits the global crop yield and ecological environment safety, and causes serious economic losses and ecological crisis. Saline-alkali land is still the main low-yield farmland resource in China, but the high concentration of exchangeable sodium in the soil causes soil compaction, resulting in poor soil structure and decreased fertility. In addition, soil salinity reduces the acquisition and transport of plant nutrients, leading to nutrient imbalance, causing the production capacity to decrease and the surrounding environment to degrade, which seriously restricts the improvement of local land use efficiency and ecological environment safety. Therefore, it is of great significance to study the improvement measures of saline-alkali soil and improve the production capacity in ensuring the stability of arable land and ecological safety.

[0003] Current methods for improving saline-alkali land mainly include physical and water conservancy engineering regulation, biological improvement, and chemical conditioning. Among them, physical improvement and water conservancy measures such as guest soil, construction of drainage, irrigation, and leaching system, although have strong operability and remarkable effect on saline-alkali land improvement, are expensive and the regulation effect is affected by soil texture, weather, water quality, etc., which is not sustainable and difficult to be widely applied; biological improvement improves saline-alkali land by planting and cultivating salt-tolerant microorganisms of selected salt-tolerant plants, but its time efficiency for soil quality improvement is poor and the stability and long-term effect of its influence on the ecological system still need to be observed. Chemical improvement mainly reduces the concentration of soil soluble sodium ions and soil salinity through ion exchange, acid-base neutralization, and ion balance principles. The commonly used chemical conditioning improvement materials are gypsum, desulfurized gypsum, ferrous sulfate, humic acid, and furfural residue, etc., which have the advantages of economy, quick effect, and strong operability, but also have the disadvantages of low efficiency or secondary pollution, which limits the improvement effect of saline-alkali land. Therefore, there is an urgent need for a new type of soil conditioner with high efficiency and low cost to improve the saline-alkali land soil environment and increase crop yield. SUMMARY

[0004] The application aims to provide a novel soil conditioner. The soil conditioner combines chemical and biological modification techniques, effectively improves the physical and chemical properties of soil, increases soil biological activity, promotes crop growth, improves crop yield and disease resistance, and truly realizes the improvement and full utilization of saline-alkali soil.

[0005] The application adopts the following technical solutions:

[0006] The saline-alkali soil conditioner is prepared from the following raw materials by weight: modified chitosan 10-20 parts, rice husk carbon 20-30 parts, gamma-aminobutyric acid 3-6 parts, polyacrylamide 1-5 parts, activator 1-3 parts, humic acid 20-40 parts, blast furnace slag 10-20 parts, and composite microbial agent 1-3 parts.

[0007] Further, the modified chitosan is prepared by the following method:

[0008] (1) chitosan is dissolved in a 2.5% (v / v) acetic acid solution, an appropriate amount of 10% (w / w) glutaraldehyde solution is added, and stirring is performed for 5 h to obtain a cross-linked chitosan solution;

[0009] (2) a 3% mass percentage citric acid solution is prepared, N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride and N-hydroxysuccinimide are sequentially added to the solution, and stirring is performed for 3 h to obtain an activated citric acid solution;

[0010] (3) the cross-linked chitosan solution obtained in step (1) is mixed with the activated citric acid solution obtained in step (2) and reacted for 3 h, then an appropriate amount of tetrahydrofuran is added and stirring is performed for 2 h, and the mixed solution after reaction is directly freeze-dried into powder to obtain the modified chitosan.

[0011] Further, the mass-volume ratio of the chitosan to the acetic acid solution is 2 g:100 mL; and the mass ratio of the chitosan to the glutaraldehyde is 1:0.3.

[0012] Further, the mass ratio of the citric acid solution, N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride and N-hydroxysuccinimide in step (2) is 100:2.5:3.

[0013] Further, the volume ratio of the cross-linked chitosan solution, the activated citric acid solution and tetrahydrofuran in step (3) is 2:1:0.1.

[0014] Further, the activator is sodium lignosulfonate and KOH in a mass ratio of 2:1.

[0015] Further, the blast furnace slag has a specific surface area of 500 m 2 / kg.

[0016] Further, the composite microbial agent is composed of Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum; and the preparation method of the composite microbial agent is as follows: Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum are inoculated into LB culture medium respectively, and then cultured at 28°C under oscillation until the bacterial content is O.D 600 ≈3.0, and then mixed in a volume ratio of 1:2:1 and dried to obtain the composite microbial agent.

[0017] Further, the Trichoderma viride is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.7339; the Chaetomium globosum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.17184; and the Corynebacterium glutamicum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC1.1886.

[0018] The application further provides a preparation method of the saline-alkali soil conditioner.

[0019] (1) the modified chitosan is prepared by the above method;

[0020] (2) the modified chitosan is added into 10 times of deionized water, ultrasonic dispersion is performed for 10-15 min, then the activator composed of sodium lignosulfonate and KOH in a mass ratio of 2:1 is added, ultrasonic dispersion is continuously performed for 30 min, and then the modified chitosan after activation is obtained by drying at 65°C;

[0021] (3) Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum are inoculated into LB culture medium respectively, and then cultured at 28°C under oscillation until the bacterial content is O.D 600≈3.0, and then mixed in a volume ratio of 1:2:1 and dried to obtain the composite microbial agent;

[0022] (4) the activated modified chitosan, the compound microbial inoculant, rice husk carbon, gamma-aminobutyric acid, polyacrylamide, humic acid and blast furnace slag are mixed according to weight ratio, and then granulated by a granulator to obtain granules with a particle size of 1-3 mm.

[0023] The soil conditioner is used in an amount of 20-30 kg per mu, and the application amount is adjusted according to the actual land conditions.

[0024] The beneficial effects of the present application are:

[0025] (1) The modified chitosan used in the present application has a three-dimensional grid porous structure, and the pores are uniform and dense. The structure has a large specific surface area, can expose more active sites, and can enhance the adsorption capacity of various nutrients in the soil. After the modified chitosan is activated by the activator of the present application, the adsorption performance of the porous structure is activated, the adsorption of salt and alkali in the soil is increased, and the formation of soil aggregate structure is promoted, and the infiltration rate of salt is improved, so as to reduce the salinity, adjust the pH value and reduce the soil hardening.

[0026] (2) The present application combines chemical improvement technology and biological improvement technology. The modified chitosan used in the present application can effectively improve the physical and chemical properties of the soil, and can also work with the compound microbial inoculant of the present application to increase the biological activity of the soil. The special network and pore structure of the modified chitosan of the present application provides a suitable ecological environment for microorganisms in the soil, promotes the growth of various beneficial microorganisms, reduces the number of harmful microorganisms, promotes crop growth, improves crop yield and disease resistance, and truly realizes the improvement and full utilization of saline-alkali soil.

[0027] (3) The soil conditioner of the present application can significantly reduce the soil acidity and alkalinity, salt content and bulk density after being applied to the soil, promote the formation of soil aggregate structure, greatly improve the soil organic matter content and thus improve the soil fertility, regulate crop growth, and ultimately improve the crop yield and quality by improving the physical and chemical properties of the soil. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The TEM diagram of the modified chitosan prepared in the present application. DETAILED DESCRIPTION

[0029] The present application will be further described in detail below in combination with specific examples.

[0030] Example 1

[0031] A saline-alkali soil conditioner is prepared from the following raw materials in parts by weight: modified chitosan 10 parts, rice husk carbon 20 parts, gamma-aminobutyric acid 3 parts, polyacrylamide 1 part, activator 1 part, humic acid 20 parts, blast furnace slag 10 parts and compound microbial inoculant 1 part.

[0032] The complex microbial agent is composed of Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum; the Trichoderma viride is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.7339; the Chaetomium globosum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.17184; and the Corynebacterium glutamicum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC1.1886.

[0033] The activator is sodium lignosulfonate and KOH with a mass ratio of 2:1.

[0034] The blast furnace slag has a specific surface area of ≥500 m 2 / kg.

[0035] The preparation method of the saline-alkali soil conditioner comprises the following steps:

[0036] (1) preparing modified chitosan: a) dissolving 2 g of chitosan in 100 ml of 2.5% (v / v) acetic acid solution, adding 6 g of 10% (mass fraction) glutaraldehyde solution, and stirring for 5 h to obtain a cross-linked chitosan solution; b) preparing a 3% (mass fraction) citric acid solution, and then adding 2.5 g of N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC.HCl) and 3 g of N-hydroxysuccinimide (NHS) into 100 ml of the citric acid solution in sequence, and stirring for 3 h to obtain an activated citric acid solution; c) mixing 100 ml of the cross-linked chitosan solution obtained in step a) with 50 ml of the activated citric acid solution obtained in step b) and reacting for 3 h, and then adding 5 g of tetrahydrofuran and stirring for 2 h, and directly freeze-drying the mixed solution after the reaction into powder to obtain the modified chitosan;

[0037] (2) adding the modified chitosan into 10 times of deionized water, ultrasonically dispersing for 10-15 min, adding an activator composed of sodium lignosulfonate and KOH with a mass ratio of 2:1 into the solution, continuing to ultrasonically disperse for 30 min, and then drying at 65°C to obtain the activated modified chitosan;

[0038] (3) inoculating the Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum into LB culture medium respectively, and oscillating and culturing at 28°C until the bacterial content is O.D 600≈3.0, then mixing and drying the three bacteria according to a volume ratio of 1:2:1 to obtain the complex microbial agent;

[0039] (4) The obtained activated modified chitosan, compound microbial inoculant, rice husk carbon, gamma-aminobutyric acid, polyacrylamide, humic acid and blast furnace slag are mixed according to the weight ratio, and granulated by a granulator to obtain granules with a particle size of 1-3 mm.

[0040] Example 2

[0041] A saline-alkali soil conditioner is prepared from the following raw materials by weight: modified chitosan 15 parts, rice husk carbon 25 parts, gamma-aminobutyric acid 5 parts, polyacrylamide 3 parts, activator 2 parts, humic acid 30 parts, blast furnace slag 15 parts, and compound microbial inoculant 2 parts.

[0042] The compound microbial inoculant is composed of Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum; the Trichoderma viride is purchased from the China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.7339; the Chaetomium globosum is purchased from the China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.17184; and the Corynebacterium glutamicum is purchased from the China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC1.1886.

[0043] The activator is sodium lignosulfonate and KOH in a mass ratio of 2:1.

[0044] The specific surface area of the blast furnace slag is ≥500 m 2 / kg.

[0045] The preparation method of the saline-alkali soil conditioner comprises the following steps:

[0046] (1) Preparation of modified chitosan: a) 2 g of chitosan is dissolved in 100 ml of 2.5% (v / v) acetic acid solution, 6 g of 10% mass fraction glutaraldehyde solution is added, and stirring is performed for 5 h to obtain a cross-linked chitosan solution; b) a 3% mass percentage citric acid solution is prepared, 2.5 g of N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC.HCl) and 3 g of N-hydroxysuccinimide (NHS) are sequentially added to 100 ml of the citric acid solution, and stirring is performed for 3 h to obtain an activated citric acid solution; c) 100 ml of the cross-linked chitosan solution obtained in step a) is mixed with 50 ml of the activated citric acid solution obtained in step b) for reaction for 3 h, then 5 g of tetrahydrofuran is added, stirring is performed for 2 h, and the mixed solution after reaction is directly freeze-dried into powder to obtain the modified chitosan;

[0047] (2) The modified chitosan is added into 10 times of deionized water, and ultrasonic dispersed for 10-15 min, then the activator composed of sodium lignosulfonate and KOH with a mass ratio of 2:1 is added, and ultrasonic dispersed for 30 min, and then dried at 65℃ to obtain the activated modified chitosan;

[0048] (3) The Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum are inoculated into LB medium respectively, and cultured at 28℃ until the bacterial content is O.D 600≈3.0, then mixed with a volume ratio of 1:2:1, and dried to obtain the composite microbial inoculant;

[0049] (4) The activated modified chitosan, the composite microbial inoculant, rice husk charcoal, gamma-aminobutyric acid, polyacrylamide, humic acid and blast furnace slag are mixed uniformly according to the weight ratio, and then granulated by a granulator to obtain particles with a particle size of 1-3 mm.

[0050] Example 3

[0051] A saline-alkali soil conditioner is prepared from the following raw materials by weight: modified chitosan 20 parts, rice husk charcoal 30 parts, gamma-aminobutyric acid 6 parts, polyacrylamide 5 parts, activator 3 parts, humic acid 40 parts, blast furnace slag 20 parts, and composite microbial inoculant 3 parts.

[0052] The composite microbial inoculant is composed of Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum; the Trichoderma viride is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.7339; the Chaetomium globosum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.17184; and the Corynebacterium glutamicum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 3, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC1.1886.

[0053] The activator is composed of sodium lignosulfonate and KOH with a mass ratio of 2:1.

[0054] The specific surface area of the blast furnace slag is ≥500 m 2 / kg.

[0055] The preparation method of the above saline-alkali soil conditioner comprises the following steps:

[0056] (1) Preparation of modified chitosan: a) 2g of chitosan is dissolved in 100ml of 2.5% (v / v) acetic acid solution, 6g of 10% mass fraction glutaraldehyde solution is added, and the reaction is stirred for 5h to obtain a cross-linked chitosan solution; b) a 3% mass percentage citric acid solution is prepared, 2.5g of N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC.HCl) and 3g of N-hydroxysuccinimide (NHS) are sequentially added to 100ml of the citric acid solution, and stirred for 3h to obtain an activated citric acid solution; c) 100ml of the cross-linked chitosan solution obtained in step a) is mixed with 50ml of the activated citric acid solution obtained in step b) and reacted for 3h, then 5g of tetrahydrofuran is added and stirred for 2h, and the mixed solution after reaction is directly freeze-dried into powder to obtain the modified chitosan;

[0057] (2) The modified chitosan is added to 10 times the amount of deionized water, ultrasonically dispersed for 10-15min, then the activator composed of sodium lignosulfonate and KOH in a mass ratio of 2:1 is added, and ultrasonically dispersed for another 30min, and then dried at 65℃ to obtain the activated modified chitosan;

[0058] (3) Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum are inoculated into LB medium respectively, and cultured at 28℃ under shaking until the bacterial content is O.D 600≈3.0, then mixed according to a volume ratio of 1:2:1 and dried to obtain a composite microbial inoculant;

[0059] (4) The activated modified chitosan, the composite microbial inoculant, and the rice husk charcoal, gamma-aminobutyric acid, polyacrylamide, humic acid, and blast furnace slag are mixed uniformly according to the weight ratio, and then granulated by a granulator to obtain particles with a particle size of 1-3mm.

[0060] Comparative Example 1

[0061] A saline-alkali soil conditioner is prepared from the following raw materials in parts by weight: chitosan 20 parts, rice husk charcoal 30 parts, gamma-aminobutyric acid 6 parts, polyacrylamide 5 parts, activator 3 parts, humic acid 40 parts, blast furnace slag 20 parts, and composite microbial inoculant 3 parts.

[0062] The complex microbial agent is composed of Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum; the Trichoderma viride is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.7339; the Chaetomium globosum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC3.17184; and the Corynebacterium glutamicum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Haidian District, Beijing, with a preservation number of CGMCC1.1886.

[0063] The activator is sodium lignosulfonate and KOH with a mass ratio of 2:1.

[0064] The blast furnace slag has a specific surface area of greater than or equal to 500 m 2 / kg.

[0065] The preparation method of the saline-alkali soil conditioner comprises the following steps:

[0066] (1) chitosan is added into 10 times of deionized water, and an activator composed of sodium lignosulfonate and KOH with a mass ratio of 2:1 is added after ultrasonic dispersion for 10-15 min, and then the mixture is dried after ultrasonic dispersion for another 30 min at 65°C to obtain activated chitosan;

[0067] (2) Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum are inoculated into LB culture medium respectively, and then cultured at 28°C until the bacterial content is O.D 600≈3.0, and then the three kinds of bacteria are mixed in a volume ratio of 1:2:1 and dried to obtain a complex microbial agent;

[0068] (3) the activated chitosan, the complex microbial agent, rice husk charcoal, γ-aminobutyric acid, polyacrylamide, humic acid and blast furnace slag are mixed uniformly according to the weight ratio, and then granulated by a granulator to obtain particles with a particle size of 1-3 mm.

[0069] The soil conditioner of the comparative example 3 is basically the same as that of the example 3 in terms of formula composition and preparation method, except that the chitosan is not modified.

[0070] Comparative example 2

[0071] A saline-alkali soil conditioner is prepared from the following raw materials in parts by weight: modified chitosan 20 parts, rice husk charcoal 30 parts, γ-aminobutyric acid 6 parts, polyacrylamide 5 parts, humic acid 40 parts, blast furnace slag 20 parts and complex microbial agent 3 parts.

[0072] The complex microbial agent is composed of Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum; the Trichoderma viride is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Hua-yuan District, Beijing, with a preservation number of CGMCC3.7339; the Chaetomium globosum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Hua-yuan District, Beijing, with a preservation number of CGMCC3.17184; and the Corynebacterium glutamicum is purchased from China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Beichen West Road, Hua-yuan District, Beijing, with a preservation number of CGMCC1.1886.

[0073] The specific surface area of the blast furnace slag is ≥500 m 2 / kg.

[0074] The preparation method of the saline-alkali soil conditioner comprises the following steps:

[0075] (1) Preparation of modified chitosan: a) 2 g of chitosan is dissolved in 100 ml of 2.5% (v / v) acetic acid solution, 6 g of 10% (mass fraction) glutaraldehyde solution is added, and stirring is carried out for 5 h to obtain a crosslinked chitosan solution; b) a 3% (mass fraction) citric acid solution is prepared, 2.5 g of N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC.HCl) and 3 g of N-hydroxysuccinimide (NHS) are sequentially added to 100 ml of the citric acid solution, and stirring is carried out for 3 h to obtain an activated citric acid solution; c) 100 ml of the crosslinked chitosan solution obtained in step a) is mixed with 50 ml of the activated citric acid solution obtained in step b) for reaction for 3 h, then 5 g of tetrahydrofuran is added, stirring is carried out for 2 h, and the mixed solution after reaction is directly freeze-dried into powder to obtain the modified chitosan;

[0076] (2) The Trichoderma viride, Chaetomium globosum and Corynebacterium glutamicum are respectively inoculated into LB culture medium, and are subjected to oscillation culture at 28°C until the bacterial content is O.D 600≈3.0, then are mixed according to a volume ratio of 1:2:1, and are dried to obtain the complex microbial agent;

[0077] (3) The modified chitosan, the complex microbial agent, rice husk charcoal, γ-aminobutyric acid, polyacrylamide, humic acid and blast furnace slag are uniformly mixed according to weight ratio, and are granulated by a granulator to obtain particles with a particle size of 1-3 mm.

[0078] The formula composition and preparation method of the novel soil conditioner of the comparative example are basically the same as those of example 3, and the only difference is that the novel soil conditioner does not contain an activator component and a corresponding preparation method processing step.

[0079] Comparative example 3

[0080] The formulation and preparation method of the novel soil conditioner in this comparative example are basically the same as those in Example 3, except that the activator component is only sodium lignosulfonate.

[0081] Comparative Example 4

[0082] The formulation and preparation method of the novel soil conditioner in this comparative example are basically the same as those in Example 3, except that the activator component is only KOH.

[0083] Comparative Example 5

[0084] The formulation and preparation method of the novel soil conditioner in this comparative example are basically the same as those in Example 3, except that the compound microbial agent does not contain Trichoderma viride.

[0085] Comparative Example 6

[0086] The formulation and preparation method of the novel soil conditioner in this comparative example are basically the same as those in Example 3, except that the compound microbial agent does not contain *Chaetoceros hygroscopicus*.

[0087] Comparative Example 7

[0088] The formulation and preparation method of the novel soil conditioner in this comparative example are basically the same as those in Example 3, except that the compound microbial agent does not contain Bacillus glutamicum.

[0089] Test case

[0090] The modified chitosan obtained in Example 3 of this invention was observed by scanning electron microscopy, such as... Figure 1 As shown, from Figure 1 It can be seen that the modified chitosan prepared by this invention has a three-dimensional network structure with relatively uniform and dense pores. This structure has a large specific surface area, which exposes more active sites and enhances the adsorption capacity for salinity, alkalinity, various heavy metal ions, and nutrients in the soil. It promotes the formation of soil aggregates, increases the infiltration rate of salts, thereby reducing salinity, regulating pH, and reducing soil compaction. The adsorbed nutrients are slowly released under the action of microorganisms, resulting in good water and fertilizer retention.

[0091] Field application trials

[0092] The experiment was conducted in a saline-alkali experimental field in Dongjian Village, Yitong Manchu Autonomous County, Heilongjiang Province. The average soil pH was 9.6, the surface soil salinity reached 7.15%, and the soil bulk density was 1.33 g / cm³. 3The corn is planted, and the tested variety is Longken 1140. The test field is divided into 11 groups, including examples 1-3, comparative examples 1-7, and a blank control group. Each group has an area of 2 mu, and a 1 m wide protection row is arranged between each group. Different soil conditioners are applied to each group at an application amount of 25 Kg / mu. The blank control group is not applied with any soil conditioner, and the remaining processes are all conventional field management. At the harvest stage, the number of dead seedlings per mu, the plant height (50 randomly selected plants are averaged), the corn hundred-grain weight, and the harvest yield per mu are counted. The specific experimental results are shown in Table 1.

[0093] Table 1: Field planting application test results

[0094]

[0095] As can be seen from the data in Table 1, compared with the blank control, the yield and quality of corn are significantly improved after the saline-alkali soil conditioner prepared by the application is applied to the soil. The average yield per mu of corn applied with the saline-alkali soil conditioner prepared in examples 1-3 is 648.8 Kg, which is 227.9 Kg higher than that of the blank control, an increase of 54.1%, and the grains are more plump, the average hundred-grain weight is 381.9 g, and the number of dead plants is less.

[0096] In order to further test the improvement effect of the soil conditioner of the application on the physical and chemical properties of the saline-alkali soil, the physical and chemical properties of the soil before and after planting in each treatment group are determined. The soil in the range of 0-20 cm in depth of the test field is taken and detected.

[0097] 1.1 Soil physical properties

[0098] The soil physical property determination items include soil bulk density, porosity, aeration porosity, and water-stable large aggregates.

[0099] Soil bulk density and porosity: The bulk density is determined by the cutting ring method, combined with the determination of soil saturated water content and field water capacity, to calculate the total porosity and aeration porosity of the soil, respectively.

[0100] Water-stable large aggregates: The soil aggregate analyzer is used for determination, and the content of water-stable aggregates with a particle size of >0.25 mm is measured.

[0101] 1.2 Soil chemical properties

[0102] Soil pH value: The pH meter (Lei magnet, Shanghai) method is used for determination, and the pure water is boiled in advance to remove carbon dioxide. The water-soil ratio is 2.5:1.0 (volume / mass ratio) according to the recommendation of the International Society of Soil Science.

[0103] Soil organic matter: The potassium dichromate oxidation-external heating method is used for determination.

[0104] Soil salt content: The mass method was used to determine the soil salt content.

[0105] Microbial amount: The fumigation-extraction-capacity analysis method was used for determination.

[0106] The specific test results are shown in Table 2:

[0107] Table 2 Soil improvement effect data

[0108]

[0109] As can be seen from the data in Table 2, after planting, the soil treated with the saline-alkali soil conditioner prepared by the examples 1-3 of the present application was detected, compared with the original soil, the soil salt content and pH were significantly reduced, the average soil bulk density was 1.01 g / cm 3 , decreased by 23.8%; the average total porosity was 61.7%, increased by 39%; the average large aggregate was 38.9%, increased by 39.8%; the average microbial amount was 93.7 million / g, increased by 57.2%; while the blank control group without using any soil conditioner was compared with the original soil, the soil salt content and pH were increased. As can be seen from the data of Comparative Examples 1 and 2, the modified chitosan prepared by the present application as a soil conditioner has a better effect than ordinary chitosan, which is because the modified chitosan has a three-dimensional porous structure with uniform and dense pores, the structure has a large specific surface area, which can expose more active sites and enhance the adsorption capacity of salt and alkali components and various nutrients in the soil; as can be seen from Comparative Examples 3-4, after the modified chitosan is activated by the activator compounded by the present application, the adsorption activity is activated, the adsorption of salt and alkali components in the soil is increased, and at the same time, the formation of soil aggregate structure is promoted, the infiltration rate of salt is increased, so as to reduce the salinity, adjust the pH, and reduce the soil compaction. The two activators are complementary and indispensable. As can be seen from the data of Comparative Examples 5-7, the green wood mold, transparent hairy core and glutamic acid rod-shaped bacteria are respectively cultured and compounded according to the volume ratio of 1:2:1, the synergistic effect of each strain can better treat the saline-alkali soil, can significantly reduce the pH and salt content of the saline-alkali soil, and significantly improve the organic matter content and microbial content. Thus, the saline-alkali soil conditioner of the present application can significantly reduce the pH value and salt content of the soil, improve the soil organic matter content, increase the soil aggregate structure, improve the water and fertilizer retention capacity of the soil, significantly improve the physicochemical properties of the saline-alkali soil, and then improve the yield and quality of crops, and has good application and popularization value.

[0110] It should be noted that the above examples are only part of the preferred modes of implementing the present application, not all. Obviously, based on the above examples of the present application, all other examples obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

Claims

1. A soil conditioner for saline-alkali land, characterized in that, It is made from the following raw materials in parts by weight: 10-20 parts modified chitosan, 20-30 parts rice husk charcoal, 3-6 parts γ-aminobutyric acid, 1-5 parts polyacrylamide, 1-3 parts activator, 20-40 parts humic acid, 10-20 parts blast furnace slag, and 1-3 parts compound microbial agent; the compound microbial agent is composed of Trichoderma viride, Chaetomium hygroscopicum, and Corynebacterium glutamicum. The modified chitosan was prepared by the following method: (1) Dissolve chitosan in 2.5% (v / v) acetic acid solution, add an appropriate amount of 10% (v / v) glutaraldehyde solution, stir and react for 5 h to obtain cross-linked chitosan solution; (2) Prepare a citric acid solution with a mass percentage concentration of 3%, and add N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride and N-hydroxysuccinimide to the solution in sequence, stir for 3 hours to obtain an activated citric acid solution; (3) Mix the cross-linked chitosan solution obtained in step (1) with the activated citric acid solution obtained in step (2) and react for 3 hours. Then add an appropriate amount of tetrahydrofuran and stir for 2 hours. Freeze-dry the mixed solution after reaction into powder to obtain modified chitosan. The preparation method of the saline-alkali soil conditioner includes the following steps: Add modified chitosan to 10 times the amount of deionized water, ultrasonically disperse for 10-15 minutes, then add an activator composed of sodium lignosulfonate and KOH in a mass ratio of 2:1, continue ultrasonication for 30 minutes, and dry at 65℃ to obtain activated modified chitosan; mix the obtained activated modified chitosan, composite microbial agent, rice husk charcoal, γ-aminobutyric acid, polyacrylamide, humic acid, and blast furnace slag evenly according to the weight ratio.

2. The soil conditioner for saline-alkali land according to claim 1, characterized in that, The mass-to-volume ratio of chitosan to acetic acid solution is 2g:100mL; the volume ratio of chitosan acetic acid solution to glutaraldehyde solution is 1:0.

3.

3. The soil conditioner for saline-alkali land according to claim 1, characterized in that, In step (2), the mass ratio of citric acid solution, N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride and N-hydroxysuccinimide is 100:2.5:

3.

4. The soil conditioner for saline-alkali land according to claim 1, characterized in that, In step (3), the volume ratio of cross-linked chitosan solution, activated citric acid solution and tetrahydrofuran is 2:1:0.

1.

5. The soil conditioner for saline-alkali land according to claim 1, characterized in that, The activator is composed of sodium lignosulfonate and KOH in a mass ratio of 2:

1.

6. The soil conditioner for saline-alkali land according to claim 1, characterized in that, The specific surface area of ​​the blast furnace slag is ≥500m². 2 / kg.

7. The soil conditioner for saline-alkali land according to claim 1, characterized in that, The compound microbial agent is composed of *Trichoderma viride*, *Chaetoceros hymenopus*, and *Corynebacterium glutamicum*. The preparation method of the compound microbial agent is as follows: *Trichoderma viride*, *Chaetoceros hymenopus*, and *Corynebacterium glutamicum* are inoculated separately into LB medium and cultured with shaking at 28°C until the bacterial count reaches OD0.

05. 600 The concentration is 3.0, and then the mixture is dried after being mixed in a volume ratio of 1:2:

1.

8. The soil conditioner for saline-alkali land according to claim 7, characterized in that, The preservation number of the *Trichoderma viride* is CGMCC3.7339; the preservation number of the *Chaetoceros hygroscopicus* is CGMCC3.17184; and the preservation number of the *Corynebacterium glutamicum* is CGMCC1.1886.

9. A method for preparing a soil conditioner for saline-alkali land according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Modified chitosan is prepared using the method described in claim 1; (2) Add the modified chitosan to 10 times the amount of deionized water, ultrasonically disperse for 10-15 min, then add the activator composed of sodium lignosulfonate and KOH in a mass ratio of 2:1, continue ultrasonication for 30 min, and then dry at 65℃ to obtain the activated modified chitosan. (3) Inoculate Trichoderma viride, Chaetomium hygroscopicum and Corynebacterium glutamicum into LB medium and culture at 28°C with shaking until the bacterial count reaches OD. 600 The concentration was 3.0, and then the mixture was dried after being mixed at a volume ratio of 1:2:1 to obtain a composite microbial agent; (4) After the activated modified chitosan, composite microbial agent, rice husk charcoal, γ-aminobutyric acid, polyacrylamide, humic acid and blast furnace slag are mixed evenly according to the weight ratio, the mixture is granulated into particles with a particle size of 1-3 mm by a granulator.

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