Method for improving moderate and severe saline-alkali soil

Abstract

The invention discloses a method for improving moderate and severe saline-alkali soil, and belongs to the technical field of saline-alkali soil improvement. The method comprises the following steps: improving the saline-alkali soil by adopting an improvement device; the improved device comprises a sponge layer, a drip irrigation tape, a straw layer, a humidity sensor and a thin film layer. The sponge layer is used for being laid on the saline-alkali soil to be improved, the drip irrigation tape is arranged in the sponge layer or between the sponge layer and the saline-alkali soil, the straw layer is arranged on the surface of the sponge layer, the film layer is arranged on the surface of the straw layer, and the humidity sensor is arranged between the film layer and the straw layer. According to the rule that salt in bottom soil and shallow underground water is easy to migrate upwards through the capillary action and the salt content of surface soil is increased due to the evaporation action, soil moisture is evaporated, meanwhile, the interiors of a sponge layer and a straw layer are kept moist, and salt carried along with moisture evaporation in the soil is absorbed. The method is easy to operate, the saline-alkali soil improvement cost can be effectively reduced, and the productivity and crop yield of moderately severe saline-alkali farmland are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of saline-alkali land improvement, and in particular to a method for improving moderate to severe saline-alkali land. Background Art

[0002] Soil salinization is prone to occur in arid and semi-arid regions, impacting crop growth and yield. Currently, saline-alkali land improvement typically involves chemical, physical, biological, and hydraulic methods. The combination of these four methods offers advantages such as low cost, rapid effectiveness, independence from supporting projects, and flexible formulations. Each measure should be used in concert to achieve comprehensive improvement of saline-alkali land and promote a virtuous cycle of soil water and salt dynamics. Each measure requires the coordination of irrigation and drainage engineering to achieve the desired effect, and sufficient freshwater is crucial for these improvement measures. However, the severe scarcity of freshwater resources in saline-alkali soil areas has limited the implementation of these measures. Consequently, the development and utilization of abundant shallow groundwater and low-quality water in saline areas is gaining increasing attention. For areas with moderate to severe soils, high salt content, and large saline-alkali areas, large-scale engineering projects are costly and ineffective, and there is a lack of cost-effective and feasible improvement technologies.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The object of the present invention is to provide a method for improving moderate to severe saline-alkali land to solve or improve the above technical problems.

[0005] The present invention can be implemented like this: In a first aspect, the present invention provides a method for improving moderate to severe saline-alkali land, wherein an improvement device is used to improve the saline-alkali land to be improved; The improved device includes a sponge layer, a drip irrigation tape, a straw layer, a moisture sensor, and a film layer; Among them, the sponge layer is used to be laid on the saline-alkali land to be improved, the drip irrigation belt is arranged inside the sponge layer or between the sponge layer and the saline-alkali land, the straw layer is set on the surface of the sponge layer, the film layer is set on the surface of the straw layer, and the humidity sensor is set between the film layer and the straw layer.

[0006] In an optional embodiment, the sponge layer is used to be laid on the soil surface or shallow soil area of ​​saline-alkali land.

[0007] In an optional embodiment, before laying the sponge layer, the saline-alkali land to be improved is also leveled.

[0008] In an optional embodiment, the thickness of the straw layer is 2 cm / g to 15 cm / g based on the salt content of the saline-alkali land to be treated; The ratio of the thickness of the sponge layer to the thickness of the straw layer is 1:1 to 1:3.

[0009] In an optional embodiment, the sponge used in the sponge layer is a highly absorbent sponge.

[0010] In an optional embodiment, the sponge is a polyurethane sponge.

[0011] In an optional embodiment, the bottom of the sponge layer has a corrugated structure.

[0012] In an optional embodiment, there are multiple drip irrigation tapes, and the multiple drip irrigation tapes are arranged in the same direction and at intervals.

[0013] In an optional embodiment, the straw layer is formed by crushing and compacting biological straw.

[0014] In an optional embodiment, the biostraw includes at least one of corn straw and rice straw.

[0015] In an optional embodiment, the length of the pulverized biostraw does not exceed 5 cm.

[0016] In an optional embodiment, the film layer is provided with a plurality of evaporation holes.

[0017] In an optional embodiment, the plurality of evaporation holes are divided into a plurality of groups arranged at intervals, and the projections of the evaporation holes in each group and the drip irrigation belts on the same horizontal plane are staggered.

[0018] In an optional embodiment, the diameter of the evaporation hole is 1.5 mm to 2.5 mm.

[0019] In an optional embodiment, in the same group, the distance between two adjacent evaporation holes is 4 cm to 6 cm.

[0020] In an optional embodiment, the number of humidity sensors is equal to the number of drip irrigation tapes, and a humidity sensor is correspondingly provided above each drip irrigation tape.

[0021] In an optional embodiment, the straw layer after absorbing salt is fermented to produce biogas or used as livestock feed.

[0022] The beneficial effects of the present invention include: The improvement method provided by the present invention mainly utilizes the principle that when water evaporates from the soil, salt ions are carried upward. A sponge layer and a straw layer are used to cooperate to intercept the salt ions. The sponge layer is laid on the saline-alkali land to be improved to ensure that the sponge layer is in full contact with the saline-alkali land, absorbs soil moisture and transitions to the upper straw layer. The straw layer is covered on the sponge layer as the main carrier for absorbing salt, and is covered with a film layer with holes to prevent the evaporation rate in the sponge layer and the straw layer from being too fast. This method uses straw as the main body, has low cost, can effectively reduce the salt content in saline-alkali soil, meet the planting conditions of crops, and increase the yield of crops. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a schematic diagram of the improved device of the present invention used in conjunction with saline-alkali land; Figure 2 It is a cross-sectional view of the improved device in the present invention.

[0025] Icons: 01-film layer; 02-humidity sensor; 03-straw layer; 04-sponge layer; 05-drip irrigation tape; 06-salt-alkali land; 07-evaporation hole. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0027] The method for improving moderate to severe saline-alkali land provided by the present invention is described in detail below.

[0028] The present invention provides a method for improving moderate to severe saline-alkali land. The method adopts an improvement device to improve the saline-alkali land to be improved.

[0029] Combine Figure 1 and Figure 2 ( Figure 2 The evaporation hole 07 is not shown in the figure), the improved device provided by the present invention includes a sponge layer 04, a drip irrigation belt 05, a straw layer 03, a humidity sensor 02 and a film layer 01.

[0030] Among them, the sponge layer 04 is used to be laid on the saline-alkali land 06 to be improved, the drip irrigation belt 05 is arranged inside the sponge layer 04 or between the sponge layer 04 and the saline-alkali land 06, the straw layer 03 is arranged on the surface of the sponge layer 04, the film layer 01 is arranged on the surface of the straw layer 03, and the humidity sensor 02 is arranged between the film layer 01 and the straw layer 03.

[0031] The above-mentioned "sponge layer 04" and "straw layer 03" can be collectively referred to as "sponge-straw interlayer".

[0032] The improvement method provided by the present invention mainly utilizes the principle that when water evaporates from the soil, it carries salt ions upward. A sponge-straw interlayer is used to intercept the salt ions. A sponge-straw interlayer of a certain thickness is laid on the saline-alkali land 06 to ensure that the sponge layer 04 is in full contact with the saline-alkali land 06, absorbing soil moisture and transitioning to the upper straw layer 03. The straw layer 03 is covered on the sponge layer 04 as the main carrier for absorbing salt. It is covered with a film layer 01 with holes to prevent the evaporation rate in the sponge-straw interlayer from being too fast. This method uses straw as the main component, is low in cost, can effectively reduce the salt content in saline-alkali soil, meet the planting conditions of crops, and increase the yield of crops.

[0033] It should be noted that, with respect to the present invention, when improving the saline-alkali land 06, the improvement device prepared in advance according to the above structure can be directly used; or the various structures of the improvement device can be laid and arranged in sequence on the saline-alkali land 06 to be improved according to the structure of the above-mentioned improvement device. For example, a sponge layer 04 with a drip irrigation tape 05 arranged inside can be laid on the surface of the saline-alkali land 06 to be improved first, and then a straw layer 03 can be laid on the surface of the sponge layer 04, and then a humidity sensor 02 can be set on the surface of the straw layer 03, and then a film layer 01 can be covered. In some optional embodiments, the sponge layer 04 can be laid on the soil surface of the saline-alkali land 06. In other optional embodiments, the sponge layer can also be laid in the shallow soil area of ​​the saline-alkali land 06 to increase the amount of salt intercepted by the straw to a greater extent.

[0034] In some optional embodiments, before laying the sponge layer 04 , the saline-alkali land 06 to be improved is leveled to improve the consistency of evaporation rate at each location.

[0035] In the present invention, the straw layer 03 serves as the main salt retention layer and is the main carrier for absorbing evaporated salt; the sponge layer 04 serves as a moisture transition layer; the sponge layer 04 absorbs the moisture carrying salt and transitions it to the upper straw layer 03. In some optional embodiments, based on the salt content of the saline-alkali land 06 to be treated, the thickness of the straw layer 03 can be 2 cm / g to 15 cm / g, such as 2 cm / g, 5 cm / g, 8 cm / g, 10 cm / g, 12 cm / g or 15 cm / g, etc., or it can be other values ​​within the range of 2 cm / g to 15 cm / g.

[0036] If the thickness of the straw layer 03 is too thin, it is not conducive to fully absorbing soil salt within the evaporation limit; if the thickness of the straw layer 03 is too thick, it is not conducive to evaporation and wastes straw.

[0037] In some optional embodiments, the thickness of the straw layer 03 is thicker than the thickness of the sponge layer 04. The ratio of the thickness of the sponge layer 04 to the thickness of the straw layer 03 can be 1:1 to 1:3, such as 1:1, 1:1.5, 1:2, 1:2.5 or 1:3, or other values ​​within the range of 1:1 to 1:3.

[0038] In the present invention, the sponge used in the sponge layer 04 is a highly absorbent sponge, such as a polyurethane sponge. In some preferred embodiments, the bottom of the sponge layer 04 has a corrugated structure, such as a spherical corrugated structure, so as to better fit the soil surface.

[0039] In the present invention, the purpose of setting the drip irrigation belt 05 is to ensure that the soil is moist and the evaporation occurs normally. For example, when the soil is dry, the soil is replenished with water in time to ensure that the evaporation occurs normally.

[0040] The number of the drip irrigation belt 05 can be one, or multiple (such as 2, 3 or more). Preferably, the number of the drip irrigation belt 05 is multiple to better adjust the soil moisture.

[0041] When there are multiple drip irrigation belts 05, the multiple drip irrigation belts 05 are preferably arranged in the same direction and at intervals. In some preferred embodiments, the distances between each two adjacent drip irrigation belts 05 are equal.

[0042] In the present invention, the straw layer 03 is formed by crushing and compacting biological straw, wherein the biological straw may illustratively but not limitatively include at least one of corn straw and rice straw.

[0043] In some optional embodiments, the length of the crushed biostraw can be set according to the characteristics of the application site, for example, it can be 0.1 cm, 0.5 cm, 1 cm, 3 cm, 5 cm or 7 cm, etc. In some preferred embodiments, the length of the crushed biostraw does not exceed 5 cm.

[0044] In the present invention, the film layer 01 may be a plastic film layer 01 , and the plastic film layer 01 is provided with a plurality of evaporation holes 07 to ensure the evaporation of water while preventing the evaporation rate from being too fast.

[0045] In some optional embodiments, the plurality of evaporation holes 07 are divided into a plurality of groups arranged at intervals, and the projections of the evaporation holes 07 and the drip irrigation belts 05 on the same horizontal plane are staggered to better increase the evaporation amount in the sponge-straw interlayer.

[0046] In some optional embodiments, the aperture of the evaporation hole 07 may be 1.5 mm to 2.5 mm, such as 1.5 cm, 2 cm or 2.5 cm, or may be other values ​​within the range of 1.5 mm to 2.5 mm.

[0047] In some optional embodiments, in the same group, the distance between two adjacent evaporation holes 07 may be 4 cm to 6 cm, such as 4 cm, 4.5 cm, 5 cm, 5.5 cm or 6 cm, or other values ​​within the range of 4 cm to 6 cm.

[0048] The plastic film layer 01 with the above structure can ensure evaporation and keep the straw moist while also keeping the straw powder in an aggregated shape for easy secondary utilization after collection.

[0049] In the present invention, humidity sensor 02 is used to monitor the humidity of straw layer 03, providing a basis for opening and closing drip irrigation tape 05. For example, if the humidity of straw layer 03 is lower than a preset value, drip irrigation tape 05 is opened; if the humidity of straw layer 03 is higher than the preset value, drip irrigation tape 05 is closed. The opening and closing of drip irrigation tape 05 can be controlled manually or automatically using a common PLC.

[0050] The number of humidity sensors 02 is equal to the number of drip irrigation belts 05. A humidity sensor 02 is correspondingly provided above each drip irrigation belt 05 to ensure that the moisture content at each position in the sponge-straw interlayer meets the standard.

[0051] In some optional embodiments, the straw layer 03 after absorbing salt can also be fermented to generate biogas or used as livestock feed.

[0052] As mentioned above, the method for improving moderate to severe saline-alkali land provided by the present invention has low cost, simple structure, and is easy to manufacture and implement. Among them, straw can be recycled, which is beneficial to improving the utilization efficiency of biomass materials. The method provided by the present invention is preferably carried out in seasons with high temperature and high evaporation intensity, such as spring or summer. When in use, a sponge layer 04 of appropriate thickness is laid in advance to cover the soil to ensure the basic level of the sponge layer 04. Drip irrigation belts 05 are evenly arranged under or inside the sponge layer 04 to ensure that the soil is moist and evaporation occurs normally. The sponge layer 04 is covered with a properly compacted straw layer 03. The length of the straw is determined by the salinity of the soil in the target area. The straw layer 03 is covered with a film layer 01 to ensure that the salty water fully enters the straw layer 03, and the humidity sensor 02 under the film layer 01 is used for monitoring. The drip irrigation belt 05 is turned on when the moisture content is low. This method can remove soil salt and reduce the soil salt content to reach the threshold for crop planting. At the same time, the straw used can be reused as a raw material for biogas fermentation. Therefore, the present invention provides a new method with low cost and good effect for the treatment of saline-alkali land 06.

[0053] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0054] Example 1 This embodiment provides a method for improving moderate to severe saline-alkali land, the method comprising: The saline-alkali land 06 to be improved is leveled, a sponge layer 04 is laid on its surface, a drip irrigation tape 05 is placed inside the sponge layer 04, and a straw layer 03 is laid on top of the sponge layer 04. A humidity sensor 02 is placed on the straw layer 03, and a film layer 01 is placed over the straw layer 03. If the humidity of the straw layer 03 falls below a preset value, the drip irrigation tape 05 is turned on; if the humidity exceeds the preset value, the drip irrigation tape 05 is turned off accordingly. The opening and closing of the drip irrigation tape 05 is manually controlled. The straw layer 03, which has absorbed salt, is fermented and used to produce biogas.

[0055] Based on the salt content of the saline-alkali land 06 to be treated, the thickness of the straw layer 03 is 5 cm / g, the thickness of the sponge layer 04 is 3 cm, and the ratio of the thickness of the sponge layer 04 to the thickness of the straw layer 03 is 3:5.

[0056] The sponge used in the sponge layer 04 is polyurethane sponge, and the bottom of the sponge layer 04 has a spherical corrugated structure. The number of the drip irrigation belts 05 is 2, and the two drip irrigation belts 05 are arranged in the same direction and at intervals.

[0057] The straw layer 03 is formed by compacting the corn straw after crushing, and the length of the crushed corn straw is 0.5 cm.

[0058] Film layer 01 is a plastic film layer 01, equipped with 48 evaporation holes 07. These 48 evaporation holes 07 are arranged in three spaced groups, each group consisting of two spaced rows, each row containing eight spaced evaporation holes 07. On the same horizontal plane, the projections of two drip irrigation tapes 05 are located between the projections of the first and second groups of evaporation holes 07, and between the projections of the second and third groups of evaporation holes 07, respectively. Each evaporation hole 07 has a diameter of 2 mm; within the same group, the distance between adjacent evaporation holes 07 is 5 cm.

[0059] There are two humidity sensors 02 , and one humidity sensor 02 is correspondingly provided above each drip irrigation belt 05 .

[0060] Example 2 The difference between this embodiment and embodiment 1 is that the drip irrigation tape 05 is arranged between the sponge layer 04 and the saline-alkali land 06 .

[0061] Example 3 The difference between this embodiment and embodiment 1 is that the sponge layer 04 is laid in the shallow soil area of ​​the saline-alkali land 06 .

[0062] Example 4 The difference between this embodiment and embodiment 1 is that the straw layer 03 is formed by crushing and compacting rice straw.

[0063] Example 5 The difference between this embodiment and embodiment 1 is that, based on the salt content of the saline-alkali land 06 to be treated, the thickness of the straw layer 03 is 2 cm / g, and the ratio of the thickness of the sponge layer 04 to the thickness of the straw layer 03 is 1:1.

[0064] Example 6 The difference between this embodiment and embodiment 1 is that, based on the salt content of the saline-alkali land 06 to be treated, the thickness of the straw layer 03 is 15 cm / g, and the ratio of the thickness of the sponge layer 04 to the thickness of the straw layer 03 is 1:3.

[0065] Example 7 The difference between this embodiment and embodiment 1 is that the straw layer 03 after absorbing salt is fermented and used as livestock feed.

[0066] Test Example 1 A 50 cm x 50 cm x 50 cm soil box was filled to a depth of 40 cm to simulate saline-alkali land to be improved. Two of these boxes were equipped with an improvement device according to Example 1 and Comparative Example 1, respectively. A control was also used without the improvement device. The two boxes were treated under the same high-temperature, intense evaporation conditions (temperature > 30°C) (simulating sunlight exposure). Various soil parameters were compared between the two boxes. The results are shown in Table 1. Each value in the table represents the average value of the surface soil.

[0067] Table 1 Results comparison table

[0068] It can be seen from Table 1 that under the same soil conditions per unit volume, the method provided in Example 1 has a significant desalination effect as a whole.

[0069] Test Example 2 According to the method in Experimental Example 1 (all other conditions of the improved device were the same as those in Example 1), the changes in various data after 144 hours of application of straw interlayers of different mass were studied in three soils with different salinity (respectively recorded as in-situ soil 1, in-situ soil 2, and in-situ soil 3). The results are shown in Tables 2 to 4. The data in the tables are the average values ​​of the surface soil from 0 cm to 40 cm.

[0070] Table 2 Results comparison table

[0071] Table 3 Results comparison table

[0072] Table 4 Results comparison table

[0073] It can be seen from Tables 2 to 4 that soils with different salinity all have a desalination effect after being treated with straw interlayers of different qualities.

[0074] In summary, the method for improving moderate to severe saline-alkali land provided by the present invention has low cost, simple structure, and is easy to manufacture and implement. Among them, straw can be recycled, which is conducive to improving the utilization efficiency of biomass materials. The method provided by the present invention is preferably carried out in seasons with high temperature and high evaporation intensity, such as spring or summer. When in use, a sponge layer 04 of appropriate thickness is laid in advance to cover the soil to ensure the basic level of the sponge layer 04. Drip irrigation belts 05 are evenly arranged below or inside the sponge layer 04 to ensure that the soil is moist and evaporation occurs normally. The sponge layer 04 is covered with a properly compacted straw layer 03. The length of the straw is determined by the salinity of the soil in the target area. The straw layer 03 is covered with a film layer 01 to ensure that the salty water fully enters the straw layer 03, and the humidity sensor 02 under the film layer 01 is used for monitoring. The drip irrigation belt 05 is turned on when the moisture content is low. This method can remove soil salt and reduce the soil salt content to reach the threshold for crop planting. At the same time, the straw used can be reused and used as raw materials for biogas fermentation.

[0075] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for improving moderate to severe saline-alkali land, characterized in that: Improvement equipment is used to improve the saline-alkali land to be improved; The improved device includes a sponge layer, a drip irrigation belt, a straw layer, a humidity sensor and a film layer; The sponge layer is used to be laid on the saline-alkali land to be improved, the drip irrigation belt is arranged inside the sponge layer or between the sponge layer and the saline-alkali land, the straw layer is arranged on the surface of the sponge layer, the film layer is arranged on the surface of the straw layer, and the humidity sensor is arranged between the film layer and the straw layer.

2. The method according to claim 1, characterized in that The sponge layer is used to be laid on the soil surface or shallow soil area of ​​the saline-alkali land; Preferably, before laying the sponge layer, the method further comprises leveling the saline-alkali land to be improved.

3. The method according to claim 1, characterized in that The thickness of the straw layer is 2 cm / g to 15 cm / g based on the salt content of the saline-alkali land to be treated; The ratio of the thickness of the sponge layer to the thickness of the straw layer is 1:1 to 1:

3.

4. The method according to any one of claims 1 to 3, characterized in that The sponge used in the sponge layer is a highly absorbent sponge; Preferably, the sponge is a polyurethane sponge; Preferably, the bottom of the sponge layer has a corrugated structure.

5. The method according to any one of claims 1 to 3, characterized in that There are multiple drip irrigation belts, and the multiple drip irrigation belts are arranged in the same direction and at intervals.

6. The method according to any one of claims 1 to 3, characterized in that The straw layer is formed by crushing and compacting biological straw; Preferably, the biostraw includes at least one of corn straw and rice straw; Preferably, the length of the pulverized biostraw does not exceed 5 mm.

7. The method according to claim 5, characterized in that The film layer is provided with a plurality of evaporation holes.

8. The method according to claim 7, characterized in that The plurality of evaporation holes are divided into a plurality of groups arranged at intervals, and the projections of the evaporation holes in each group and the drip irrigation belts on the same horizontal plane are staggered; Preferably, the evaporation hole has a diameter of 1.5 mm to 2.5 mm; Preferably, in the same group, the distance between two adjacent evaporation holes is 4 cm to 6 cm.

9. The method according to claim 5, characterized in that The number of the humidity sensors is equal to the number of the drip irrigation belts, and one humidity sensor is correspondingly provided above each of the drip irrigation belts.

10. The method according to claim 1, characterized in that The salt-absorbed straw layer is fermented to produce biogas or used as livestock feed.

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