Method for treating moderate and severe saline-alkali soil

Abstract

The invention discloses a moderate-severe saline-alkali soil treatment method which comprises the following steps: soil prediction and pretreatment: predicting the depth of an impermeable interlayer, digging out heavy clay outside the soil, discharging water and standing, and determining the position of the impermeable interlayer through a measuring marker post; precisely measuring and scribing the treatment area, controlling the scribing interval size, and laying white powder marks; soil plowing and purification liquid application: deeply plowing a lineation area by a soil plowing machine, and breaking hardening of a plowing ground layer in combination with deep scarification; the water is mixed with the gypsum and the ardealite to obtain purified liquid, and the purified liquid is conveyed to the ploughing area; the saline-alkali soil conditioner has the beneficial effects that the saline-alkali soil quality can be remarkably improved, the salt content is reduced, the soil acidity and alkalinity are improved, and the soil fertility and crop growth conditions are improved; by introducing novel materials such as iron-based biochar, the heavy metal adsorption capacity and pollution remediation capacity of the soil are further enhanced, and powerful support is provided for sustainable utilization of the saline-alkali soil.

Description

Technical Field

[0001] The invention belongs to the technical field of saline-alkali land treatment, and specifically relates to a method for treating moderate to severe saline-alkali land. Background Art

[0002] Salt-alkali land directly harms crops and causes crop yield reduction; salinized soil is due to high soluble salt content, excessive soil solution concentration, and high osmotic pressure, which prevents crops from growing normally and causes crop yield reduction; the reason is that crops absorb water with the help of the osmotic effect of plant root hairs. When the soil contains more soluble salt, the soil solution concentration increases, so the osmotic pressure increases accordingly, making it difficult for crop root hairs to absorb water, or even unable to absorb enough water, causing crops to become dehydrated or wither. At the same time, some salt in saline-alkali soil directly poisons or corrodes the root system of crops, which also affects the normal growth or death of crops, causing crop yield reduction or crop failure; the presence of salt and alkali can have an adverse effect on the physical properties and fertility of cultivated soil, cause great damage to the land, and seriously affect the development and improvement of soil productivity; salt-alkali land not only damages crops and soil, but also damages the production, life and ecological environment of people in the irrigation area.

[0003] A method for treating moderate to severe saline-alkali land with publication number CN113575013B is disclosed, which includes the following steps: excavating the heavy clay outside the soil and recording the depth of the excavation, then draining water in the excavated area, letting it stand for a period of time, and using an external measuring rod to detect the depth of the impermeable interlayer; measuring and distinguishing the land to be treated, controlling the spacing of the markings within a specified interval, and laying white powder in the area where the markings are required; using an external high-horsepower locomotive to plow the marked area, the plowing depth is the measured depth, and deep loosening is combined to break the compaction of the plowing layer; according to the land to be purified, prepare an appropriate amount of water and desulfurized gypsum, the ratio of desulfurized gypsum to water is set to 1:15, and use an external mixing device to mix the purified liquid so that the gypsum is fully mixed in the water source; using an external pumping device to transport the purified liquid to the pre-plowed excavated area in turn, so that the purified liquid runs through the entire saline-alkali land, let it stand for a period of time, and then use an external pumping device to pump out the water source.

[0004] Existing technologies, such as the patent with publication number CN113575013B, have proposed a method for treating saline-alkali land, but there is still room for improvement in terms of improving soil fertility, enhancing soil buffering capacity, and maintaining soil improvement effects for a long time. Summary of the invention

[0005] The purpose of the present invention is to provide a method for treating moderate to severe saline-alkali land, so as to solve the problems existing in the existing saline-alkali land treatment methods, such as insufficient soil fertility, limited soil pH regulation effect, and difficulty in sustaining the improvement effect.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for treating moderate to severe saline-alkali land, comprising the following steps:

[0007] Soil prediction and pretreatment: predict the depth of the impermeable interlayer, remove the heavy clay outside the soil, drain water and let it stand, and determine the position of the impermeable layer by measuring the benchmark; accurately measure and mark the treatment area, control the marking interval size, and lay white powder markers;

[0008] Soil tillage and application of purification liquid: The tiller deeply tills the marked area, combined with deep loosening to break up the compacted plowed soil layer; water is mixed with gypsum and phosphogypsum to obtain purification liquid, which is then transported to the tilled area to evenly penetrate the saline-alkali land, and then left to stand to extract excess water;

[0009] Drainage and fertilization optimization: bury drainage pipes around the hard layer to ensure effective drainage of water in the treatment area, prepare mixed fertilizers, and increase the organic matter content and buffering capacity of the soil; apply the mixed fertilizers evenly in the tillage area and till and mix them evenly;

[0010] Agricultural planting and soil maintenance: Before planting crops, open a water trough around the fertilizer and fill it with water, and control the distance between the water trough and the crops; implement crop rotation, intercropping, and interplanting methods; regularly check the soil condition, add mixed fertilizers in time, and maintain the balance of soil fertility and pH.

[0011] As a preferred technical solution of the present invention, the mixed fertilizer includes inorganic fertilizer, mineral fertilizer and iron-based biochar.

[0012] As a preferred technical solution of the present invention, the preparation method of the iron-based biochar is as follows:

[0013] Choose organic waste as raw material;

[0014] The selected organic waste is pyrolyzed in a high temperature oxygen-free or low oxygen environment;

[0015] The iron is introduced into the biochar during or after pyrolysis;

[0016] Conduct nitrification and reduction chemical treatment;

[0017] The iron-based biochar is washed to remove impurities, and then dried to remove moisture; and ground to obtain an iron-based biochar product of a desired particle size.

[0018] As a preferred technical solution of the present invention, the organic waste includes crop straw, wood residues, and animal feces.

[0019] As a preferred technical solution of the present invention, during or after pyrolysis, iron is introduced into biochar by mixing biomass with iron-containing substances before pyrolysis, or by loading iron onto the surface or inside of biochar by impregnation or adsorption after pyrolysis.

[0020] As a preferred technical solution of the present invention, the white powder is talcum powder.

[0021] As a preferred technical solution of the present invention, intercropping adopts a combination of plant heights.

[0022] As a preferred technical solution of the present invention, intercropping is one or a combination of at least two of early intercropping and late intercropping, deep intercropping and shallow intercropping, and rack within rack.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] It can significantly improve the quality of saline-alkali soil, reduce salt content, improve soil pH, and improve soil fertility and crop growth conditions;

[0025] By introducing new materials such as iron-based biochar, the soil's heavy metal adsorption capacity and pollution remediation capabilities have been further enhanced, providing strong support for the sustainable utilization of saline-alkali land. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the treatment method of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] See also Figure 1 , which is the first embodiment of the present invention, provides a method for treating moderate to severe saline-alkali land, comprising the following steps:

[0030] Soil prediction and pretreatment: predict the depth of the impermeable interlayer, remove the heavy clay outside the soil, drain water and let it stand, and determine the position of the impermeable layer by measuring the benchmark; accurately measure and mark the treatment area, control the marking interval size, and lay white powder marks; the white powder is talcum powder;

[0031] Soil tillage and application of purification liquid: The tiller deeply tills the marked area, combined with deep loosening to break up the compacted plowed soil layer; water is mixed with gypsum and phosphogypsum to obtain purification liquid, which is then transported to the tilled area to evenly penetrate the saline-alkali land, and then left to stand to extract excess water;

[0032] Drainage and fertilization optimization: bury drainage pipes around the hard layer to ensure effective drainage of water in the treatment area, prepare mixed fertilizers, and increase the organic matter content and buffering capacity of the soil; apply the mixed fertilizers evenly in the tillage area and till and mix them evenly;

[0033] Agricultural planting and soil maintenance: Before planting crops, open a water trough around the fertilizer and fill it with water, and control the distance between the water trough and the crops; implement crop rotation, intercropping, and interplanting methods; regularly check the soil condition, add mixed fertilizers in time, and maintain the balance of soil fertility and pH.

[0034] In this embodiment, preferably, the mixed fertilizer includes inorganic fertilizer, mineral fertilizer and iron-based biochar; iron-based biochar is a new type of biomass material, which is made by high-temperature pyrolysis and then nitrification, reduction and other treatments, and its main component is iron-containing biochar; iron-based biochar has good chemical stability and biological activity, and can be used as an environmentally friendly and efficient material to be widely used in various fields, such as wastewater treatment, soil remediation, biomass energy, etc.; compared with traditional biochar, iron-based biochar has higher adsorption and catalytic properties, can more effectively remove heavy metal ions and organic pollutants, and can also improve soil fertility and improve soil environment; in the future, with the improvement of environmental awareness and the continuous advancement of technology, iron-based biochar is expected to become an important environmentally friendly material and make greater contributions to the sustainable development of mankind; product features: rich in stable organic carbon and huge specific surface area, can adsorb and passivate soil heavy metals and pesticide residues, and repair damaged soil; improve soil quality, adjust soil pH, improve fertilizer efficiency, and restore soil vitality; can be combined with cadmium and arsenic in the soil to form a residual state, and the passivation state is stable and lasting;

[0035] In this embodiment, preferably, the preparation method of iron-based biochar is as follows:

[0036] Select organic waste as raw material; organic waste includes crop straw, wood residues, and animal manure;

[0037] The selected organic waste is pyrolyzed in a high temperature oxygen-free or low oxygen environment;

[0038] Introducing iron into biochar during or after pyrolysis; by mixing biomass with iron-containing substances before pyrolysis, or by loading iron onto the surface or inside of biochar by impregnation or adsorption after pyrolysis;

[0039] In order to further improve the performance of iron-based biochar, chemical treatments such as nitrification and reduction are also required; these treatments can change the valence and existence form of iron, improve its stability and activity in biochar, and thus enhance its adsorption and catalytic properties;

[0040] The iron-based biochar is washed to remove impurities, and then dried to remove moisture; and ground to obtain an iron-based biochar product of a desired particle size.

[0041] Example 2

[0042] See also Figure 1 , which is the second embodiment of the present invention, is based on the previous embodiment, except that:

[0043] Crop rotation refers to the planting of different crops or multiple cropping combinations in the same field in sequence between seasons and years. By rotating the types of crops, the accumulation of specific pests and diseases in the soil can be reduced, thereby reducing the occurrence of pests and diseases. Different crops have different absorption of soil nutrients. Crop rotation can ensure the balanced utilization of soil nutrients and avoid one-sided consumption. Water-land rotation and other methods can also change the ecological environment of the soil, improve soil aeration and organic matter decomposition, and promote the reproduction of beneficial microorganisms in the soil.

[0044] Intercropping refers to the planting method of two or more crops in rows or strips on the same field in the same growing season. Reasonable intercropping can reduce the harm of repeated cropping, inhibit pests and diseases, and promote crop yield and income.

[0045] Specific methods include:

[0046] Plant height matching: For example, intercropping corn with soybeans or mung beans is conducive to ventilation and light transmission, and improves the utilization rate of light energy;

[0047] Different root depths: Deep-rooted crops are paired with shallow-rooted crops to fully utilize nutrients and water in the soil;

[0048] Intercropping is a method of planting or transplanting the next season's crop between plants or rows in the late growth period of the previous season's crop. Intercropping can make full use of the growing season, improve the multiple cropping index, and increase the yield per unit area.

[0049] Specific methods include:

[0050] Early interplanting with late: early-maturing vegetables interplanted with late-maturing vegetables;

[0051] Deep interplanting with shallow: deep root vegetables interplanted with shallow root vegetables;

[0052] Rack within rack: crops on racks are planted intertwined.

[0053] Experimental verification:

[0054] 1.1 Experimental site selection

[0055] Select representative saline-alkali land plots to ensure that the initial soil conditions (such as salt content, pH value, organic matter content, etc.) are similar among the experimental plots to reduce the impact of natural variation on the experimental results;

[0056] 1.2 Experimental Grouping

[0057] A control group (no treatment), a traditional treatment group (using conventional saline-alkali land improvement methods, such as irrigation with fresh water, application of gypsum, etc.) and a new material treatment group (application of iron-based biochar or other new improvement materials) were set up;

[0058] 1.3 Processing Implementation

[0059] Implement corresponding treatment measures on each group of plots to ensure that the treatment amount, frequency and method are consistent;

[0060] Detailed soil parameters and climatic conditions before and after treatment were recorded.

[0061] 2. Monitoring indicators

[0062] 2.1 Soil quality indicators

[0063] Salt content: measured by conductivity meter or drying weighing method;

[0064] pH value: measured using a pH meter;

[0065] Organic matter content: Determined by potassium dichromate oxidation-external heating method;

[0066] Soil fertility: including the content of nutrients such as nitrogen, phosphorus and potassium, measured using corresponding standard methods;

[0067] 2.2 Crop Growth Conditions

[0068] Seed germination rate: sow standard crop seeds on the treated soil and record the germination rate;

[0069] Crop growth status: Regularly measure crop height, leaf area, biomass and other indicators;

[0070] Yield and quality: Determine crop yield and quality parameters (such as nutrient content, taste, etc.) at harvest.

[0071] 2.3 Heavy metal adsorption capacity

[0072] Heavy metal content in soil: The changes in the content of heavy metals (such as lead and cadmium) in the soil before and after treatment were measured by atomic absorption spectroscopy or inductively coupled plasma mass spectrometry (ICP-MS);

[0073] Adsorption test: Under laboratory conditions, simulate heavy metal pollution and evaluate the adsorption efficiency of heavy metals by materials such as iron-based biochar.

[0074] 3. Data Analysis

[0075] 3.1 Use statistical analysis software (such as SPSS, R language, etc.) to process and analyze the experimental data and compare whether the differences between the groups are statistically significant;

[0076] 3.2 Evaluate the effectiveness of new materials in reducing salinity, improving pH, increasing fertility, promoting crop growth and heavy metal adsorption.

[0077] 4. Results

[0078] 4.1 Improved soil quality and reduced salt content

[0079] Changes in salt content: After treatment, the soil salt content in the new material treatment group was significantly reduced. In contrast, the salt content in the traditional treatment group also decreased, but the decrease was smaller. The salt content in the control group remained basically unchanged.

[0080] Improved soil structure: The soil structure of the new material treatment group was significantly improved, the soil bulk density was reduced, and the porosity was increased, which was conducive to soil ventilation and water permeability. This was mainly due to the porous structure of iron-based biochar and its ability to promote the formation of soil aggregates.

[0081] 4.2 Improvement of soil pH

[0082] pH value changes: The soil pH value of the new material treatment group shifted toward neutrality, adjusting from the initial alkaline state to a range more suitable for plant growth. This change is of great significance for improving the saline-alkali soil environment and enhancing plant adaptability.

[0083] 4.3 Improved soil fertility

[0084] Increased nutrient content: The soil organic matter content of the new material treatment group increased significantly. At the same time, the nitrogen, phosphorus, potassium and other nutrient contents in the soil also increased, providing more sufficient nutrition for crop growth;

[0085] Enhanced microbial activity: The addition of iron-based biochar promotes the reproduction and activity of soil microorganisms, increases soil enzyme activity, and further enhances soil fertility;

[0086] 4.4 Improved crop growth conditions and increased yields

[0087] Improved growth conditions: Crops planted in the new material treatment group showed better growth conditions, including higher germination rate, faster growth rate and more lush plants, mainly due to improved soil quality and nutrient supply;

[0088] Improved yield and quality: At harvest, the yield of crops in the new material treatment group increased significantly, by 5% and 10% compared with the control group and the traditional treatment group, respectively. At the same time, the quality of crops also improved;

[0089] 4.5 Enhanced heavy metal adsorption capacity

[0090] Reduced heavy metal content: After applying iron-based biochar on saline-alkali land contaminated by heavy metals, the heavy metal content in the soil was significantly reduced; this is mainly due to the strong adsorption capacity of iron-based biochar for heavy metals, which effectively reduces the pollution of heavy metals to soil and crops.

[0091] Although the embodiments of the present invention have been shown and described, as detailed above, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for treating moderate to severe saline-alkali land, characterized in that: The steps include: Soil prediction and pretreatment: predict the depth of the impermeable interlayer, remove the heavy clay outside the soil, drain water and let it stand, and determine the position of the impermeable layer by measuring the benchmark; accurately measure and mark the treatment area, control the marking interval size, and lay white powder markers; Soil tillage and application of purification liquid: The tiller deeply tills the marked area, combined with deep loosening to break up the compacted plowed soil layer; water is mixed with gypsum and phosphogypsum to obtain purification liquid, which is then transported to the tilled area to evenly penetrate the saline-alkali land, and then left to stand to extract excess water; Drainage and fertilization optimization: bury drainage pipes around the hard layer to ensure effective drainage of water in the treatment area, prepare mixed fertilizers, and increase the organic matter content and buffering capacity of the soil; apply the mixed fertilizers evenly in the tillage area and till and mix them evenly; Agricultural planting and soil maintenance: Before planting crops, open a water trough around the fertilizer and fill it with water, and control the distance between the water trough and the crops; implement crop rotation, intercropping, and interplanting methods; regularly check the soil condition, add mixed fertilizers in time, and maintain the balance of soil fertility and pH.

2. A method for treating moderate to severe saline-alkali land according to claim 1, characterized in that: The mixed fertilizer includes inorganic fertilizer, mineral fertilizer and iron-based biochar.

3. A method for treating moderate to severe saline-alkali land according to claim 2, characterized in that: The preparation method of the iron-based biochar is as follows: Choose organic waste as raw material; The selected organic waste is pyrolyzed in a high temperature oxygen-free or low oxygen environment; The iron is introduced into the biochar during or after pyrolysis; Conduct nitrification and reduction chemical treatment; The iron-based biochar is washed to remove impurities, and then dried to remove moisture; and ground to obtain an iron-based biochar product of a desired particle size.

4. A method for treating moderate to severe saline-alkali land according to claim 3, characterized in that: The organic waste includes crop straw, wood residues, and animal excrement.

5. A method for treating moderate to severe saline-alkali land according to claim 3, characterized in that: During or after pyrolysis, iron is introduced into biochar by mixing biomass with iron-containing substances before pyrolysis, or by loading iron onto the surface or inside of biochar by impregnation or adsorption methods after pyrolysis.

6. A method for treating moderate to severe saline-alkali land according to claim 1, characterized in that: The white powder is talcum powder.

7. A method for treating moderate to severe saline-alkali land according to claim 1, characterized in that: Intercropping uses a combination of plant heights.

8. The method for treating moderate to severe saline-alkali land according to claim 1, characterized in that: Intercropping is one or at least two combinations of early and late, deep and shallow, and rack and rack.

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