CN115717076B - Preparation method and application of saline-alkali soil ecological improver - Google Patents

Abstract

The present invention discloses a preparation method and application of a saline-alkali soil ecological improver, belongs to the technical field of soil remediation, and particularly relates to a preparation method and application of a saline-alkali soil ecological improver. The preparation steps of the saline-alkali soil ecological improver include: (1) crushing straw and weeds, adding wine lees and mushroom residues to obtain a mixture, adding composite bacterial powder, fermenting, and obtaining a small molecule organic carbon fertilizer; (2) mixing diatoms, silicates and the small molecule organic carbon fertilizer, continuing fermentation, and obtaining a biological organic fertilizer; (3) preparing a modified composite material by mixing diatomaceous earth, magnesium sulfate solution, and ammonia water; (4) mixing the biological organic fertilizer and the modified composite material to obtain a saline-alkali soil ecological improver. The saline-alkali soil ecological improver provided by the present invention can not only repair saline-alkali soil, but also promote crop growth, increase crop yield, and realize waste resource utilization and high value utilization.

Description

Preparation method and application of saline-alkali soil ecological improver

Technical Field

The present invention relates to the technical field of soil remediation, and in particular to a preparation method and application of a saline-alkali soil ecological improver.

Background technique

Soil is the material basis and ecological environment for human survival and development. Soil pollution directly threatens human health and survival and development. Land salinization is an important issue of concern to the world today. Saline-alkali soil is a very common soil type distributed all over the world. It is a general term for various salinized and saline-alkali soil types affected by salinity. Soil salinization poses a serious threat to agricultural production around the world. The speed of saline-alkali soil quality decline and area increase is getting faster and faster. Globally, saline-alkali land is increasing at a rate of 1.0×10 ⁶ to 1.5×10 ⁶ hm ² per year. According to relevant data from UNESCO (United Nations Educational, Scientific and Cultural Organization) and FAO (United Nations Food and Agriculture Organization), the total area of saline soil in the world has reached 9.5438×10 ⁸ hm ^2. This is inseparable from human activities, such as: long-term and excessive use of chemical fertilizers, overgrazing, improper irrigation and excessive logging, which cause soil fertility to decline, soil compaction, acidification and salinization, resulting in a decrease in soil organic matter, an increase in heavy metals in the soil, and a decrease in the total amount and activity of beneficial microbial flora in the root system of crops, which seriously affects the normal growth of crops. Even good arable land has become secondary salinized soil due to accumulated damage. Salt toxicity and harmful osmotic potential lead to a decrease in vegetation growth rate, a decrease in soil carbon content, and further deterioration of its physical and chemical properties.

At present, there are mainly the following technologies for improving saline-alkali land:

1. Salt control and drainage engineering + imported soil technology

This technology mainly involves the reasonable arrangement of underground pipes and leaching layers under the planting soil layer to "isolate" and "drain" the interference of groundwater levels and deeper soil layers, block the salt source, ensure the safety of the imported soil backfill, and achieve the healthy growth of the green space ecosystem. However, this method is relatively expensive, and the imported soil cannot meet the requirements of arable land, and needs secondary improvement.

2. Concealed pipe salt discharge technology

This technology is a method of controlling salt in the planting layer by burying concealed pipes at fixed or irregular intervals underground. However, it is only applicable to soils with good soil structure and high permeability, and is not applicable to soils with strong viscosity.

3. Chemical improvement technology

This technology utilizes the chemical reaction between exogenous additives and soil colloids to improve saline-alkali land. Although it can achieve relatively good improvement effects within a certain period of time and within a certain planting soil layer, in the long run, it introduces a certain amount of Ca ²⁺ and SO ₄ ^2- into the soil. The ratio of Ca ²⁺ and Na ⁺ has improved, but the total amount of salt ions has not decreased. At the same time, the addition of exogenous substances is likely to cause secondary pollution, destroy the ecological foundation of the soil, and is not conducive to the sustainable development of agriculture.

4. Agricultural measures

It mainly includes land preparation, deep plowing and drying, returning straw to the field, planting green manure, crop rotation and intercropping, but the use of this technology alone cannot effectively improve saline-alkali soil.

The existing improvement methods generally have problems such as long treatment cycle, easy to cause secondary pollution, poor improvement of soil physical and chemical properties and fertility, and unsatisfactory comprehensive treatment effects.

Summary of the invention

In order to solve the above problems, the present invention provides a preparation method and application of a saline-alkali soil ecological improver.

To achieve the above object, the present invention provides the following technical solutions:

One of the technical solutions of the present invention is to provide a method for preparing a saline-alkali soil ecological improver, comprising the following steps:

(1) crushing straw and weeds, adding distiller's grains and mushroom residues to obtain a mixture, and then adding composite bacterial powder and fermenting to obtain a small molecule organic carbon fertilizer;

(2) mixing diatom, silicate and the small molecule organic carbon fertilizer, and continuing fermentation to obtain bio-organic fertilizer;

(3) preparing a modified composite material by mixing diatomaceous earth, magnesium sulfate solution and ammonia water;

(4) mixing the bio-organic fertilizer and the modified composite material to prepare a saline-alkali soil ecological improver;

The bacterial species in the composite bacterial powder in step (1) include: Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis.

The lees added in the present invention has a high crude protein content (up to about 25%), which is beneficial to the reproduction of microorganisms and thus improves the fermentation effect.

The bacterial species used in the present invention include Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis. The bacterial species can cooperate with each other after being combined to effectively decompose the fermentation raw materials used in the present invention to obtain small molecular organic matter, and there is no antagonism between the bacterial species. At the same time, the bacterial species used in the present invention have good nitrogen fixation and carbon fixation effects, and can be applied to planting to greatly increase crop products, and the yield-increasing effect is very significant.

Preferably, the carbon-nitrogen ratio of the mixture in step (1) is 22-30.

Preferably, the composite bacterial powder in step (1) accounts for 3-7% of the mass of the mixture; the mass ratio of Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis is 1-3:2-4:5-8:2-4.

Preferably, the fermentation temperature in step (1) is 20-40° C. and the fermentation time is 24-76 hours.

Preferably, the mass ratio of the diatom, silicate and small molecule organic carbon fertilizer in step (2) is 2-5:6-12:18-48; the diatom includes Navicula ruvalis, Nitzschia marina and Frustulia vulgaris in a mass ratio of 2-5:2-5:3-8.

Preferably, the silicate is sodium silicate or potassium silicate.

Preferably, the fermentation temperature in step (2) is 25-35° C. and the fermentation time is 48-76 hours.

Preferably, the solid-to-liquid ratio of diatomaceous earth, magnesium sulfate solution and ammonia water in step (3) is 1-3 g: 0.5-0.8 mL: 2-4 mL, wherein the mass fraction of ammonia water is 25% and the concentration of magnesium sulfate is 1 mol/L.

Preferably, the preparation steps of the modified composite material include: drying, crushing and grinding diatomaceous earth, adding magnesium sulfate solution, mixing, adding ammonia water dropwise, filtering and washing, calcining at a temperature of 500-600°C, cooling and sieving to obtain the modified composite material.

Preferably, the modified composite material in step (4) accounts for 5-9% of the mass of the bio-organic fertilizer.

The second technical solution of the present invention is to provide a saline-alkali soil ecological improver prepared according to the preparation method of the above-mentioned saline-alkali soil ecological improver.

The third technical solution of the present invention is to provide an application of the above-mentioned saline-alkali soil ecological improver in saline-alkali soil improvement, and the specific application method is: in the saline-alkali land, the soil tillage layer is plowed by 0 to 60 cm manually or mechanically, and the saline-alkali soil ecological improver is applied in an amount of 50 to 200 kg/mu.

The beneficial technical effects of the present invention are as follows:

The surface of the modified composite material component contained in the saline-alkali soil ecological improver provided by the present invention is uniformly distributed with MgO, which can enhance the adsorption of cations such as heavy metal Cd in the environment by the saline-alkali soil ecological improver. The silicate in the component can be used by diatoms, and the diatomaceous earth in the component serves as a colonization home for the growth of diatoms. At the same time, the diatomaceous earth can also be dissolved and converted into silicate, forming a "diatom-diatomaceous earth-silicate" equilibrium system, creating a perfect closed loop, and the three complement each other, so that the improvement effect of the saline-alkali soil ecological improver is enhanced.

The saline-alkali soil ecological improver provided by the present invention can not only repair the saline-alkali soil, but also promote the growth of crops, increase crop yields, and simultaneously realize the resource and high-value utilization of waste.

Detailed ways

Now, various exemplary embodiments of the present invention are described in detail, which should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the invention.

The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

The Rhodopseudomonas palustris used in the present invention was purchased from the General Microbiology Center of China National Microbiological Culture Collection Administration, with a preservation number of CGMCC No.18929; the Lactococcus plantarum used was purchased from the General Microbiology Center of China National Microbiological Culture Collection Administration, with a preservation number of CGMCC No.16487; the Bacillus subtilis used was purchased from the China Industrial Microbiological Culture Collection Administration Center, with a preservation number of CICC 20445; and the Candida utilis used was purchased from the China Industrial Microbiological Culture Collection Administration Center, with a preservation number of CICC 1768.

Cultivation of Rhodopseudomonas palustris cells: inoculate Rhodopseudomonas palustris into a culture medium (1L distilled water + 4.2g sodium acetate + 0.8g yeast extract + 1mL trace element solution, the formula of the trace element solution is: 5mg ferric chloride, 5mg copper sulfate, 1mg boric acid, 0.05mg manganese chloride, 1mg zinc sulfate, 0.5mg cobalt nitrate, add water to 1000mL) at a ratio of 5%, culture at 30°C with shaking for 72h, then expand the culture using the same culture medium, centrifuge, filter, and obtain Rhodopseudomonas palustris cells for standby use;

Cultivation of plant lactococcus cells: inoculate plant lactococcus into MRS medium (pH=6.4) at a ratio of 3%, culture at 30° C. with shaking for 24 h, then expand the culture using the same medium, centrifuge, filter, and obtain plant lactococcus cells for standby use;

Cultivation of Bacillus subtilis cells: inoculate Bacillus subtilis into a culture medium (culture medium formula: 1L distilled water + 20g glucose + 15g peptone + 5g sodium chloride + 0.5g beef extract + 20g agar, pH = 7.0) at a ratio of 5%, culture at 36°C with shaking for 14h, then expand the culture using the same culture medium, centrifuge, filter, and obtain Bacillus subtilis cells for standby use;

Cultivation of Candida utilis cells: inoculate Candida utilis into a culture medium (1L distilled water + 50g glucose + 20g yeast powder + 2g potassium dihydrogen phosphate + 1g magnesium sulfate + 1g ammonium sulfate, pH = 5.5) at a ratio of 1%, culture at 30°C with shaking for 24h, then expand the culture using the same culture medium, centrifuge, filter, and obtain Candida utilis cells for standby use.

Example 1

The preparation steps of saline-alkali soil ecological conditioner are as follows:

(1) Preparation of small molecule organic carbon fertilizer

The corn stalks and weeds are crushed, and distiller's grains and mushroom residues are added and mixed, wherein the mass ratio of the corn stalks, weeds, distiller's grains and mushroom residues is 5:3:9:6, and composite bacterial powder consisting of Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis that have been acclimated and cultured in the early stage and have a mass ratio of 2:3:6:3 is added, and fermented at 25°C for 76 hours to prepare a small molecule organic carbon fertilizer; wherein the composite bacterial powder accounts for 3wt% of the mixture of the corn stalks, weeds, distiller's grains and mushroom residues.

(2) Preparation of bio-organic fertilizer

By weight, 3 parts of diatoms, 10 parts of sodium silicate and 30 parts of small molecule organic carbon fertilizers were mixed and continued to ferment at a fermentation temperature of 30°C for 48 hours to obtain biological organic fertilizer; wherein the diatoms were composed of snow boat algae, costal nitzschia and common costal algae in a mass ratio of 3:3:7.

(3) Preparation of modified composite materials

The diatomaceous earth is dried, crushed and ground, and then a 1 mol/L magnesium sulfate solution is added and mixed. A 25 wt% ammonia water is added dropwise (0.05 mL/s). After filtering and washing, the mixture is calcined in a muffle furnace at 550° C., and finally cooled and sieved to obtain a modified composite material. The solid-liquid ratio of the diatomaceous earth, the magnesium sulfate solution and the ammonia water is 1 g: 0.6 mL: 2 mL.

(4) Preparation of saline-alkali soil ecological improver

The bio-organic fertilizer is mixed with the modified composite material to obtain a saline-alkali soil ecological improver; wherein the modified composite material accounts for 8wt% of the bio-organic fertilizer.

Example 2

The preparation steps of saline-alkali soil ecological conditioner are as follows:

(1) Preparation of small molecule organic carbon fertilizer

The corn stalks and weeds are crushed, and distiller's grains and mushroom residues are added and mixed, wherein the mass ratio of the corn stalks, weeds, distiller's grains and mushroom residues is 5:3:9:6, and composite bacterial powder consisting of Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis that have been acclimated and cultured in the early stage and have a mass ratio of 2:3:6:3 is added, and fermented at 25°C for 76 hours to prepare a small molecule organic carbon fertilizer; wherein the composite bacterial powder accounts for 6wt% of the mixture of the corn stalks, weeds, distiller's grains and mushroom residues.

(2) Preparation of bio-organic fertilizer

By weight, 3 parts of diatoms, 10 parts of sodium silicate and 30 parts of small molecule organic carbon fertilizers were mixed and continued to ferment at a temperature of 30°C for 48 hours to obtain biological organic fertilizer; wherein the diatoms were composed of snow boat algae, costal nitzschia and common costal algae in a mass ratio of 3:3:7.

(3) Preparation of modified composite materials

The diatomaceous earth is dried, crushed and ground, and then a 1 mol/L magnesium sulfate solution is added and mixed. A 25 wt% ammonia water is added dropwise (0.05 mL/s). After filtering and washing, the mixture is calcined in a muffle furnace at 550° C., and finally cooled and sieved to obtain a modified composite material. The solid-liquid ratio of the diatomaceous earth, the magnesium sulfate solution and the ammonia water is 1 g: 0.6 mL: 2 mL.

(4) Preparation of saline-alkali soil ecological improver

The bio-organic fertilizer is mixed with the modified composite material to obtain a saline-alkali soil ecological improver; wherein the modified composite material accounts for 8wt% of the bio-organic fertilizer.

Example 3

The preparation steps of saline-alkali soil ecological conditioner are as follows:

(1) Preparation of small molecule organic carbon fertilizer

The corn stalks and weeds are crushed, and distiller's grains and mushroom residues are added and mixed, wherein the mass ratio of the corn stalks, weeds, distiller's grains and mushroom residues is 5:3:9:6, and composite bacterial powder consisting of Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis that have been acclimated and cultured in the early stage and have a mass ratio of 2:3:6:3 is added, and fermented at 25°C for 76 hours to prepare a small molecule organic carbon fertilizer; wherein the composite bacterial powder accounts for 6wt% of the mixture of the corn stalks, weeds, distiller's grains and mushroom residues.

(2) Preparation of bio-organic fertilizer

By weight, 3 parts of diatoms, 10 parts of sodium silicate and 30 parts of small molecule organic carbon fertilizers were mixed and continued to ferment at a fermentation temperature of 30°C for 48 hours to obtain biological organic fertilizer; wherein the diatoms were composed of snow boat algae, costal nitzschia and common costal algae in a mass ratio of 2:3:5.

(3) Preparation of modified composite materials

The diatomaceous earth was dried, crushed and ground, and then 1 mol/L magnesium sulfate solution was added and mixed. 25 wt% ammonia water was added dropwise (0.05 mL/s). After filtering and washing, the mixture was calcined in a muffle furnace at 550° C., and finally cooled and sieved to obtain a modified composite material, wherein the solid-liquid ratio of the diatomaceous earth, the magnesium sulfate solution and the ammonia water was 1 g: 0.6 mL: 2 mL.

(4) Preparation of saline-alkali soil ecological improver

The bio-organic fertilizer is mixed with the modified composite material to obtain a saline-alkali soil ecological improver; wherein the modified composite material accounts for 8wt% of the bio-organic fertilizer.

Example 4

The preparation steps of saline-alkali soil ecological conditioner are as follows:

(1) Preparation of small molecule organic carbon fertilizer

The corn stalks and weeds are crushed, and distiller's grains and mushroom residues are added and mixed, wherein the mass ratio of the corn stalks, weeds, distiller's grains and mushroom residues is 5:3:9:6, and composite bacterial powder consisting of Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis, which have been acclimated and cultured in the early stage and have a mass ratio of 2:3:6:3, is added, and fermented at 25°C for 76 hours to prepare a small molecule organic carbon fertilizer; the composite bacterial powder accounts for 6wt% of the mixture of the corn stalks, weeds, distiller's grains and mushroom residues.

(2) Preparation of biological organic fertilizer

By weight, 3 parts of diatoms, 10 parts of sodium silicate and 30 parts of small molecule organic carbon fertilizers were mixed and continued to ferment at a fermentation temperature of 30°C for 48 hours to obtain biological organic fertilizer; wherein the diatoms were composed of snow boat-shaped algae and common costal algae in a mass ratio of 2:5.

(3) Composite material preparation

The diatomaceous earth was dried, crushed and ground, and then 1 mol/L magnesium sulfate solution was added and mixed. 25 wt% ammonia water was added dropwise (0.05 mL/s). After filtering and washing, the mixture was calcined in a muffle furnace at 550° C., and finally cooled and sieved to obtain a modified composite material, wherein the solid-liquid ratio of the diatomaceous earth, the magnesium sulfate solution and the ammonia water was 1 g: 0.6 mL: 2 mL.

(4) Preparation of saline-alkali soil ecological improver

The bio-organic fertilizer is mixed with the modified composite material to obtain a saline-alkali soil ecological improver; wherein the modified composite material accounts for 8wt% of the bio-organic fertilizer.

Comparative Example 1

The preparation steps of saline-alkali soil ecological conditioner are as follows:

30 parts of a mixture of crushed corn stalks, weeds, distiller's grains, and mushroom residues (wherein the mass ratio of corn stalks, weeds, distiller's grains, and mushroom residues is 5:3:9:6) are mixed and fermented with 3 parts of diatoms and 10 parts of sodium silicate at a fermentation temperature of 30°C and a fermentation time of 48 hours to obtain a biological organic fertilizer, wherein the diatoms are composed of snow boat-shaped algae, costal slit Nitzschia algae, and common costal slit algae in a mass ratio of 3:3:7. After the diatomite is dried, crushed, and ground, a 1 mol/L magnesium sulfate solution is added, mixed, and 25 wt% ammonia water is added dropwise (0.05 mL/s), filtered, washed, and calcined in a muffle furnace at 550°C, and finally cooled and sieved to obtain a modified composite material, wherein the solid-liquid ratio of the diatomite, magnesium sulfate solution, and ammonia water is 1 g: 0.6 mL: 2 mL.

The bio-organic fertilizer is mixed with the modified composite material to obtain a saline-alkali soil ecological improver; wherein the modified composite material accounts for 8wt% of the bio-organic fertilizer.

Comparative Example 2

The preparation steps of saline-alkali soil ecological conditioner are as follows:

The corn stalks and weeds are crushed, and distiller's grains and mushroom residues are added and mixed, wherein the mass ratio of the corn stalks, weeds, distiller's grains and mushroom residues is 5:3:9:6, and composite bacterial powder consisting of Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis that have been acclimated and cultured in the early stage and have a mass ratio of 2:3:6:3 is added, and fermented at 25°C for 76 hours to prepare a small molecule organic carbon fertilizer; wherein the composite bacterial powder accounts for 6wt% of the mixture of the corn stalks, weeds, distiller's grains and mushroom residues.

After drying, crushing and grinding the diatomite, 1 mol/L magnesium sulfate solution was added, mixed, 25 wt% ammonia water was added dropwise (0.05 mL/s), filtered and washed, and then calcined in a muffle furnace at 550°C, and finally cooled and sieved to obtain a modified composite material, wherein the solid-liquid ratio of the diatomite, magnesium sulfate solution and ammonia water was 1 g: 0.6 mL: 2 mL. 10 parts of sodium silicate and 30 parts of small molecular organic carbon fertilizer were mixed and continued to ferment at a fermentation temperature of 30°C and a fermentation time of 48 hours, and then 8 wt% of the modified composite material was added and mixed to obtain a saline-alkali soil ecological improver.

Comparative Example 3

The preparation steps of saline-alkali soil ecological conditioner are as follows:

The corn stalks and weeds are crushed, and the mixture is added with distiller's grains and mushroom residues, wherein the mass ratio of the corn stalks, weeds, distiller's grains and mushroom residues is 5:3:9:6, and composite bacterial powder consisting of Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis, which have been acclimated and cultured in the early stage and have a mass ratio of 2:3:6:3, is added, and the mixture is fermented at 25°C for 76 hours to prepare a small molecule organic carbon fertilizer, wherein the composite bacterial powder accounts for 6wt% of the mixture of the corn stalks, weeds, distiller's grains and mushroom residues.

3 parts of diatoms, 10 parts of sodium silicate and 30 parts of small molecule organic carbon fertilizer were mixed and continued to ferment at a fermentation temperature of 30°C and a fermentation time of 48h to obtain biological organic fertilizer; wherein the diatoms include snow boat-shaped algae, costal slit Nitzschia and common costal slit algae in a mass ratio of 3:3:10. After the diatomite was dried, crushed and ground, 1 mol/L magnesium sulfate solution was added, mixed, and 25 wt% ammonia water was added dropwise (0.05 mL/s), filtered and washed, and then calcined in a muffle furnace at 550°C, and finally cooled and sieved to obtain a modified composite material, wherein the solid-liquid ratio of diatomite, magnesium sulfate solution and ammonia water was 1g:0.6mL:2mL. The biological organic fertilizer was mixed with the composite material to obtain a saline-alkali soil ecological improver, wherein the modified composite material accounted for 8wt% of the biological organic fertilizer.

Application Examples

The saline-alkali soil ecological improvers prepared in Examples 1-4 and Comparative Examples 1-3 were applied to saline-alkali land restoration and were divided into a blank group, an experimental group 1, an experimental group 2, an experimental group 3, an experimental group 4, a control group 1, a control group 2 and a control group 3. The same fertilization mode (mechanical tillage of the soil by a rotary tiller with a tillage depth of 20 to 60 cm, the soil improver was placed in the rotary tiller, and the soil improver was applied while tilling) and management mode (conventional management methods were used) were adopted, with the following differences:

The blank group was not treated with any improver;

Experimental group 1 applied the saline-alkali soil ecological improver prepared in Example 1 before planting cabbage, 70 kg/mu;

Experimental group 2 applied the saline-alkali soil ecological improver prepared in Example 2 before planting cabbage, 70 kg/mu;

Experimental group 3 applied the saline-alkali soil ecological improver prepared in Example 3 before planting cabbage, 70 kg/mu;

Experimental group 4 applied the saline-alkali soil ecological improver prepared in Example 4 before planting cabbage, 70 kg/mu;

The control group 1 was treated with the saline-alkali soil ecological improver prepared in comparative example 1 before planting cabbage, 70 kg/mu;

The control group 2 was treated with the saline-alkali soil ecological improver prepared in comparative example 2 before planting cabbage, 70 kg/mu;

The control group 3 was applied with the saline-alkali soil ecological improver prepared in comparative example 3 before planting cabbage, 70 kg/mu.

One week later, the physical and chemical properties of the improved 0-20 cm soil in each experimental group were measured. The results are shown in Table 1.

Table 1 Physical and chemical properties of soil after being improved by various groups of saline-alkali soil ecological conditioners

It can be seen from Table 1 that the use of the saline-alkali soil ecological modifier provided by the present invention can effectively reduce the salt content and alkalinity of the saline-alkali soil and improve the physical and chemical properties of the saline-alkali soil.

The improved soil was used to carry out a planting experiment of spring king cabbage. The cabbage was harvested after 30 days and its characteristics were measured. The results are shown in Table 2.

Table 2 Yield of Spring King Cabbage Planted in Improved Soil

It can be seen from Table 2 that the soil improved by using the saline-alkali soil ecological improver provided by the present invention can significantly increase the yield of cabbage.

The above results show that the saline-alkali soil ecological improver provided by the present invention can not only repair saline-alkali land, but also promote the growth of crops, increase yields, and at the same time realize the resource and high-value utilization of waste.

The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims (9)

1. A method for preparing a saline-alkali soil ecological modifier, characterized in that it comprises the following steps: (1) Crush straw and weeds, add distiller's grains and mushroom residues to obtain a mixture, then add composite fungus powder and ferment to obtain a small molecule organic carbon fertilizer; (2) mixing diatom, silicate and the small molecule organic carbon fertilizer, and continuing fermentation to obtain biological organic fertilizer; (3) Preparing a modified composite material by mixing diatomaceous earth, magnesium sulfate solution and ammonia water; (4) mixing the bio-organic fertilizer and the modified composite material to prepare a saline-alkali soil ecological improver; The bacterial species in the composite bacterial powder in step (1) include: Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis; The mass ratio of the diatom, silicate and small molecule organic carbon fertilizer in step (2) is 2-5:6-12:18-48; the diatom is composed of Navicula nigrostachya, Nitzschia ribes and common ribes in a mass ratio of 3:3:7. 2. The method for preparing a saline-alkali soil ecological improver according to claim 1, characterized in that the composite bacterial powder in step (1) accounts for 3-7% of the mass of the mixture; and the mass ratio of the Rhodopseudomonas palustris, Lactococcus plantarum, Bacillus subtilis and Candida utilis is 1-3:2-4:5-8:2-4. 3. The method for preparing the saline-alkali soil ecological improver according to claim 1, characterized in that the fermentation temperature in step (1) is 20-40°C and the fermentation time is 24-76 hours. 4. The method for preparing the saline-alkali soil ecological improver according to claim 1, characterized in that the fermentation temperature in step (2) is 25-35°C and the fermentation time is 48-76 hours. 5. The method for preparing the saline-alkali soil ecological improver according to claim 1, characterized in that the solid-to-liquid ratio of diatomaceous earth, magnesium sulfate solution and ammonia water in step (3) is 1-3 g:0.5-0.8 mL:2-4 mL, wherein the mass fraction of ammonia water is 25% and the concentration of magnesium sulfate is 1 mol/L. 6. The method for preparing the saline-alkali soil ecological improver according to claim 5 is characterized in that the preparation steps of the modified composite material include: drying, crushing and grinding diatomaceous earth, adding magnesium sulfate solution, mixing, adding ammonia water dropwise, filtering and washing, calcining at a temperature of 500-600° C., cooling and sieving to obtain the modified composite material. 7. The method for preparing the saline-alkali soil ecological conditioner according to claim 1, characterized in that the modified composite material in step (4) accounts for 5-9% of the mass of the bio-organic fertilizer. 8. A saline-alkali soil ecological improver obtained according to the preparation method of the saline-alkali soil ecological improver according to any one of claims 1 to 7. 9. The use of the saline-alkali soil ecological improver according to claim 8 in saline-alkali soil improvement, characterized in that the soil tillage layer is plowed 0-60 cm in the saline-alkali land by manual or mechanical means, and the saline-alkali soil ecological improver is applied in an amount of 50-200 kg/mu.