Application of improvement auxiliary agent in saline-alkali soil improvement

Abstract

The invention belongs to the technical field of saline-alkali soil improvement, and particularly relates to application of an improvement auxiliary in saline-alkali soil improvement. The saline-alkali soil improvement additive is prepared by taking mushroom dreg waste generated in a microbial bacterium culture process and crushed branch residues of common cultivated plants such as switchgrass and cotton in saline-alkali soil as main components, and the saline-alkali soil improvement additive is mixed with to-be-improved saline-alkali soil according to a specific proportion, so that the soil environment of severe saline-alkali soil can also be improved. The saline-alkali soil improvement auxiliary agent has the beneficial effects that the saline-alkali soil improvement auxiliary agent provided by the invention has the advantages of being safe, green and high in resource utilization rate, and the salt content of severely hardened saline-alkali soil is remarkably reduced by application of the saline-alkali soil improvement auxiliary agent.

Description

Technical Field

[0001] The invention belongs to the technical field of saline-alkali land improvement, and particularly relates to the application of an improvement auxiliary agent in saline-alkali land soil improvement. Background Art

[0002] Saline-alkali land is a type of salt accumulation, that is, the salt contained in the soil affects the normal growth of crops. Its causes are relatively complex and are affected by many factors such as climate type, geographical conditions, soil geology, etc., but its essence is that various soluble salts are redistributed horizontally and vertically on the ground, causing salt to gradually accumulate on the soil surface in the salt-accumulating area.

[0003] At present, the methods for improving saline-alkali land mainly include physical, chemical, biological and the combination of the three. For example, the various saline-alkali land soil improvers commonly used in the market mostly use chemical + biological methods to improve saline-alkali land soil. However, the existing saline-alkali land soil improvers have the following problems when they are prepared or used:

[0004] First, most of these soil conditioners contain microbial agents and need to be obtained through complex fermentation processes, such as patent CN111154672A, patent CN110846249A, etc. This operation increases the difficulty of industrialization of soil conditioners;

[0005] On the other hand, in pursuit of soil fertility, a large amount of inorganic salts and other ingredients are added to existing soil conditioners, such as patent CN116286004A, patent CN106010560A, etc. Although such soil conditioners can promote the improvement of soil fertility in a short period of time, long-term use will disrupt the balance of water and salt ions in the local soil, causing excessively high content of certain salt ions in crops, thereby creating some unknown safety hazards to consumers; in addition, the addition of these ingredients also greatly increases the cost of soil conditioners. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides an improvement auxiliary agent and its application in improving saline-alkali soil.

[0007] The improvement auxiliary agent provided by the present invention is used in the improvement of saline-alkali land soil, and the improvement auxiliary agent comprises: raw material I and fungus residue, and the volume ratio of raw material I to fungus residue is 0-2:1-2.

[0008] Preferably, the raw material I is selected from any one of plant crushed slag, fly ash slag, and fly ash fine ash.

[0009] Further preferably, the plant crushed residues include but are not limited to the following: switchgrass crushed residues, cotton stalk crushed residues, corn stalk residues, reed residues, rice straw residues, and wheat straw residues, and the length of the plant crushed residues does not exceed 0.5 cm.

[0010] In addition, the present invention also provides a method for improving saline-alkali soil by using the above-mentioned improvement auxiliary agent, comprising the following steps:

[0011] S1: taking raw material I and fungus residue and mixing them evenly in a volume ratio of 0-2:1-2 to obtain an improved auxiliary agent, wherein the raw material I is selected from any one of plant crushed residue, fly ash residue, and fly ash fine ash;

[0012] S2 obtains saline-alkali soil from the surface of the saline-alkali land to be improved, and mixes the saline-alkali soil with the improvement auxiliary agent prepared in S1, and stirs them evenly to obtain a mixed material for use;

[0013] S3 first digs an upper pit in the saline-alkali land to be improved, then evenly spreads the mixed material obtained in S2 in the square pit, and injects water into the mixed material in the square pit. The amount of water injected is the same as the local medium rainfall in summer. The number of water injections is 2 to 3 times, and the injection interval is 12 to 48 hours.

[0014] Preferably, in the above-mentioned saline-alkali land improvement method, the volume ratio of the saline-alkali soil to the improvement auxiliary agent described in S2 is 1-2:1-2.

[0015] Preferably, the paving thickness of the mixed material in S3 is 10 to 20 cm.

[0016] As further preferred, the thickness of the mixed material in S2 is 12 to 16 cm.

[0017] Preferably, after the mixed material is laid in the pit of the saline-alkali land to be improved in S3, its height must be higher than the height of the surrounding unimproved saline-alkali land.

[0018] More preferably, after the mixed material described in S3 is laid, crushed stones are laid around the edges of the square pit to be improved. The laying width of the crushed stones is 5 to 10 cm and the thickness is 2 to 3 cm. The crushed stones are compacted after laying.

[0019] The inventors found in the long-term research process that mushroom residue has a good effect on improving saline-alkali soil (see patent CN118648405A). However, if the mushroom residue is only covered on the surface of the saline-alkali soil, the mushroom residue layer is easily washed away by heavy rain or rainstorm and lost, causing the mushroom residue layer to become thinner, affecting the improvement effect.

[0020] Based on this, the inventors mixed the improvement aid, including raw material I and fungus residue and other components, with the surface soil of the saline-alkali land, and the obtained mixture was fully combined with the soil, which greatly avoided the loss of the soil improvement aid caused by rain erosion; in addition, in order to further improve the preservation rate of the improvement aid, the present invention first dug a square pit of a certain depth on the surface of the saline-alkali land to be improved, and backfilled the mixture obtained by mixing the improvement aid and saline-alkali soil into the square pit of the saline-alkali land, which further avoided its loss rate under the action of external forces such as wind or rain.

[0021] In addition, because the surface soil of saline-alkali land is compacted and the soil gaps are narrow, the internal structure of the surface soil of saline-alkali land becomes capillary, allowing water containing soluble salts to reach the soil surface under capillary action. After the water evaporates, the soluble salts remain on the soil surface, thus maintaining the salinity. When it rains, although the salinity on the soil surface decreases briefly, the salinity continues to increase after the rain stops, repeating the cycle and maintaining it for a long time.

[0022] In the present invention, after the improvement auxiliary agents including fungus residue, plant residue and the like are fully mixed with the saline-alkali soil, the upper surface layer of the saline-alkali soil is no longer compacted, the air permeability is increased, the gaps between soil particles are enlarged, the capillary structure is destroyed, the water flow in the mixed layer on the soil surface loses the capillary action it can rely on, and can no longer flow from bottom to top in a liquid state, but can only escape from the soil gaps in the form of water vapor, the water-soluble salt loses the rising carrier, and can only stay in the compacted layer below the mixed layer, thereby maintaining the salt washing effect of the mixed layer, and the soil is improved and suitable for crop growth.

[0023] The beneficial effects of the present invention are:

[0024] Provided is a soil improvement additive for use in improving saline-alkali soil environments. The improvement additive is mainly composed of fungus residue waste generated during the microbial culture process and stalk crushed residue of common cultivated plants in saline-alkali lands, such as switchgrass and cotton, and has the advantages of being safe, green, and having a high resource utilization rate.

[0025] In addition, by mixing the improvement adjuvant with the surface soil of saline-alkali land of a certain depth that has been compacted in a certain proportion, and using artificial simulated rainfall to inject water into the saline-alkali soil, the salt content of the saline-alkali soil is significantly reduced, which is beneficial to providing a more suitable soil environment for crop growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is an experimental operation diagram of improving saline-alkali soil using an improvement auxiliary agent in the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in conjunction with specific implementation methods.

[0028] Example 1

[0029] The invention discloses a method for improving saline-alkali soil by using an improvement auxiliary agent. The improvement auxiliary agent comprises a single component, namely, fungus residue, and the saline-alkali soil and the improvement auxiliary agent fungus residue are mixed in a volume ratio of 1-2:1-2 to obtain a mixed material.

[0030] First, on a flat plot with the same salinity (salt content is above 2%), 15 square pits with a length, width and depth of 50 cm × 50 cm × 15 cm were dug, 3 in each row, a total of 5 rows, and the spacing between the square pits was 40 cm. Every 3 square pits in the above 15 square pits formed an experimental group, and a total of 5 groups were set up. For ease of understanding, the inventors hereby attach experimental photos of the improvement of saline-alkali land in the present invention, as shown in the attached Figure 1 shown.

[0031] The above-mentioned method for improving saline-alkali soil is as follows:

[0032] S1: adding 15 cm of mixed materials into the above-mentioned square pits, wherein the volume ratios of the improved auxiliary agent fungus residue and saline-alkali soil in the mixed materials are 1:2, 2:1, 1:1.5, 1.5:1, and 1:1 respectively;

[0033] S2 injects the same weight of water into the square pits where S1 adds the mixed materials. The water injection volume is the same as the local average summer rainfall. During this water injection, 5 cm of water is injected first, and then 5 cm of water is injected after 48 hours.

[0034] S3 tests the conductivity of the soil on the top of each pit in S2 at 8 a.m. every day for at least 15 consecutive times until the deviation of the average conductivity of the same group for two consecutive tests does not exceed 2%. Based on the ratio of conductivity to salt content, the salt content of the top soil after improvement of the saline-alkali land in each experimental group is calculated.

[0035] The change in soil electrical conductivity after improvement using the method of this embodiment is shown in Table 1 below.

[0036] Table 1 Changes in electrical conductivity of saline-alkali soil after improvement

[0037]

[0038] Note: K1, K2, K3 in the table represent the 1st, 2nd, and 3rd pits with the same proportion of slag and soil, respectively, and P represents the average conductivity of the three pits with the same proportion of slag and soil. The same below.

[0039] It should be noted that in this embodiment and the following embodiments, water injection is performed according to the above steps during the experiment, and the conductivity of the soil is regularly tested. However, if it rains on the day of conductivity measurement, the conductivity will not be measured on that day. For example, August 13 and September 7 in the above table are rainy days, and no conductivity measurement was performed.

[0040] The results in Table 1 show that after the saline-alkali soil was improved by mixing the above-mentioned various soil improvement additives with saline-alkali soil in different proportions, the soil environment of each experimental group was improved from super-severe saline-alkali land to medium-light saline-alkali land, and it can be seen from the soil conductivity data that with the increase of the proportion of fungus residue in the soil improvement additives, the improvement effect of salinity and alkalinity gradually increased.

[0041] Example 2

[0042] The difference from Example 1 is that the saline-alkali land soil improvement additive is a single component, namely raw material I (including: crushed switchgrass residue, cotton stalk residue, fly ash residue, fly ash fine ash, etc.). The above-mentioned soil improvement additive is mixed with saline-alkali soil in a volume ratio of 2:1 to obtain a mixed material to improve the saline-alkali land soil, and fungus residue is used as an improvement additive for comparison.

[0043] The change in soil electrical conductivity after improvement using the method of this embodiment is shown in Table 2 below.

[0044] Table 2 Changes in electrical conductivity of saline-alkali soil after improvement

[0045]

[0046] Table 2 shows the changes in soil salinity after the saline-alkali soil was improved with different types of saline-alkali soil improvement additives. After the improvement additives such as switchgrass residue, cotton stalk residue, mushroom residue, fly ash, fly ash residue, etc. were mixed with saline-alkali soil and spread on the surface of saline-alkali land, the salt improvement effect on the saline-alkali soil showed an overall decreasing trend (i.e., the salt content gradually increased).

[0047] Example 3

[0048] A method for improving saline-alkali soil using a soil improvement additive, wherein the improvement additive comprises two components, namely, fungus residue + raw material I, and the fungus residue and raw material I are mixed in a volume ratio of 1:1, and the saline-alkali soil and the improvement additive are mixed in a volume ratio of 1:1 to obtain a mixed material.

[0049] First, on a flat plot of land with the same salinity (salt content was above 2%), square pits with a length, width and depth of 50cm×50cm×15cm were dug, with 3 pits in each row, for a total of 4 rows. The spacing between the square pits was 40cm. Among the above 12 square pits, every 3 square pits formed an experimental group, for a total of 4 groups.

[0050] The above-mentioned method for improving saline-alkali soil is as follows:

[0051] S1: Add 15 cm of the mixture into the above-mentioned square pits. The ratio of the saline-alkali soil improvement additive to the saline-alkali soil in each experimental group is as follows:

[0052] Experimental group I: fungus residue: switchgrass crushed residue: saline-alkali soil = 1:1:1;

[0053] Experimental group II: fungus residue: cotton stalk crushed residue: saline-alkali soil = 1:1:1;

[0054] Experimental group III: fungus residue: fly ash residue: saline-alkali soil = 1:1:1;

[0055] Experimental group IV: fungus residue: fly ash fine ash: saline-alkali soil = 1:1:1;

[0056] S2-S3 are the same as in Example 1.

[0057] The change in soil conductivity after improvement using the soil improvement additive of this embodiment is shown in Table 3 below.

[0058] Table 3 Changes in electrical conductivity of saline-alkali soil after improvement

[0059]

[0060]

[0061] The results in Table 3 show that when the soil improvement agent and saline-alkali soil are mixed in a volume ratio of 1:1:1, the salinity of the soil after soil improvement by each improvement agent is from low to high, respectively, experimental group I, experimental group IV, experimental group II, and experimental group III.

[0062] The above experimental results show that different improvement additives mixed with saline-alkali soil have a good improvement effect on the salt content in saline-alkali soil.

[0063] However, in the actual operation of the above-mentioned Examples 1-3, especially after rain, the problem of increased salt content also occurred. This may be because the surface of the mixed material laid out at the experimental site is lower than the ground of the unimproved saline-alkali land. Figure 1 As shown, after water injection or rain, some of the saline-alkali soil improvement additives in the pit are splashed by salt water or salt mud from the adjacent saline-alkali land, causing the salt content to fluctuate and the conductivity value to rise again.

[0064] In order to avoid the above problems, the inventors have made further improvements.

[0065] Example 4

[0066] Before the experiment in this embodiment, the saline-alkali soil to be improved was first covered with an improvement agent with a thickness of 7 cm and rotary tilled to a depth of 14 cm, so as to achieve a 1:1 mixing of the improvement agent and the saline-alkali soil, and make the saline-alkali land to be improved generally higher than the adjacent land by more than 7 cm, wherein the improvement agent was the same as the improvement agent involved in Experimental Group I and Experimental Group II in Example 3.

[0067] Example 5

[0068] A square pit is dug on the surface of the heavily saline-alkali land to be improved, and the mixed materials are laid in the square pit (the mixed materials are the materials of experimental group I and experimental group II in Example 3). After the mixed materials are laid, crushed stones are laid around the edges of the square pit of the saline-alkali land to be improved. The laying width of the crushed stones is 8 cm and the thickness is 3 cm. The crushed stones are compacted after laying.

[0069] Table 4 Changes in soil conductivity of saline-alkali land in Example 4-5

[0070]

[0071] It can be seen that the physical measures adopted in Examples 4-5 can ensure that the mixed material is above the ground by a certain height to prevent the material from being washed away by rainwater, and can prevent the improved saline-alkali land from being invaded again by salt water or salt mud to cause the phenomenon of salt back.

Claims

1. The application of the improvement adjuvant in saline-alkali soil improvement is characterized in that: The improvement aid comprises: raw material I and fungus residue, and the volume ratio of raw material I to fungus residue is 0~2:1~2; The raw material I is selected from any one of plant crushed slag, fly ash slag and fly ash fine ash.

2. The use according to claim 1, characterized in that The plant crushed residues include but are not limited to the following: switchgrass crushed residues, cotton stalk crushed residues, corn stalk residues, reed residues, straw residues, and wheat straw residues. The length of the plant crushed residues does not exceed 0.5 cm.

3. A method for improving saline-alkali soil using an improvement adjuvant, characterized in that: The steps include: S1: taking raw material I and fungus residue and mixing them evenly in a volume ratio of 0-2:1-2 to obtain an improved auxiliary agent, wherein the raw material I is selected from any one of plant crushed residue, fly ash residue, and fly ash fine ash; S2 obtains saline-alkali soil from the surface of the saline-alkali land to be improved, and mixes the saline-alkali soil with the improvement auxiliary agent prepared in S1, and stirs them evenly to obtain a mixed material for use; S3 first digs a square pit on the surface of the saline-alkali land to be improved, then evenly spreads the mixed material obtained in S2 in the square pit, and injects water into the mixed material in the square pit. The amount of water injected is the same as the local average rainfall in summer. The number of water injections is 2 to 3 times, and the injection interval is 12 to 48 hours.

4. The method according to claim 3, characterized in that In S2, the volume ratio of the saline-alkali soil to the improvement auxiliary agent is 1-2:1-2.

5. The method according to claim 3, characterized in that The thickness of the mixed material in S2 is 10-20 cm.

6. The method according to claim 5, characterized in that The thickness of the mixed material in S2 is 12-16 cm.

7. The method according to claim 3, characterized in that After the mixed material is laid in the pit of the saline-alkali land to be improved in S3, its height must be higher than that of the surrounding unimproved saline-alkali land.

8. The method according to claim 3, characterized in that After the mixed material described in S3 is laid, crushed stones are laid around the edges of the square pit of the saline-alkali land to be improved. The laying width of the crushed stones is 5-10 cm and the thickness is 2-3 cm. The crushed stones are compacted after laying.

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