Sand covering-peat layered improved structure for saline-alkali soil and improved regulation and control method

Abstract

The invention relates to the technical field of saline-alkali soil improvement, in particular to a saline-alkali soil sand-peat layered improvement structure and an improvement regulation and control method.The saline-alkali soil sand-peat layered improvement structure sequentially comprises a dry branch and fallen leaf covering layer, a sand-peat mixed layer, a peat layer and a mineral gleying layer from top to bottom, and an irrigation pipeline layer is arranged in the sand-peat mixed layer and / or the peat layer; the mixing mass ratio of the sandy soil to the peat soil in the sand-peat mixing layer is (3-5): 1, the particle size of the sandy soil is 0.1-0.5 mm, and the content of organic matters in the peat soil is 30-50%. According to the sand covering-peat layered improved structure for the saline-alkali soil and the improved regulation and control method, through the design of the sand covering-peat layered structure, the dry branch and fallen leaf covering layer, the sand-peat mixed layer, the peat layer and the mineral gleying layer are arranged, water and salt migration and organic matter distribution are optimized, the local microbial activity of soil is induced to be improved, and the soil quality is improved. The improvement effect is dynamically evaluated by combining an enzyme activity threshold value in a CASH system.

Description

Technical Field

[0001] This invention relates to the field of saline-alkali land improvement technology, and in particular to a layered improvement structure and improvement control method for saline-alkali land covered with sand and peat. Background Technology

[0002] Saline-alkali land, a global soil degradation problem, is characterized by excessively high salt content (such as sodium and calcium salts) and alkaline substances, often resulting in a pH value exceeding 8.5. This severely damages soil structure, leading to soil compaction, poor aeration, and weak water and fertilizer retention capacity. It also inhibits plant root absorption of water and nutrients, causing crop growth stunts and even death. Currently, saline-alkali land improvement technologies mainly include water-based improvement, chemical improvement, biological improvement, and physical improvement. However, existing technologies generally have limitations: water-based improvement consumes a large amount of water and easily triggers secondary salinization; chemical improvement is costly and long-term use may damage the soil micro-ecology; biological improvement has a long cycle and limited effectiveness on severely saline-alkali land; and physical improvement relies on scarce topsoil resources, making large-scale application difficult.

[0003] Furthermore, single soil improvement techniques struggle to achieve the synergistic effects of salinity reduction, soil improvement, and fertility enhancement. Existing sand-covering techniques create a sand-clay interlayer that easily forms a "sand on top, clay underneath" water-blocking layer under drought conditions, exacerbating the upwelling of lower-level salts. While peat application can regulate soil pH, its loose structure easily leads to nutrient loss. However, existing methods such as drip irrigation only alleviate surface water shortages and do not address deep-seated moisture retention. Therefore, there is an urgent need for a soil improvement structure and method that can achieve stratified synergy and dynamic regulation, efficiently reducing salinity while simultaneously improving soil fertility, thus enabling the sustainable improvement of saline-alkali land. Summary of the Invention

[0004] The purpose of this invention is to provide a sand-peat stratified improvement structure and improvement regulation method for saline-alkali land. Through the design of the sand-peat stratified structure, a dead leaf cover layer, a sand-peat mixed layer, a peat layer and a mineral gleyed layer are set up respectively to optimize water and salt transport and organic matter distribution, induce the improvement of soil native microbial activity, and dynamically evaluate the improvement effect in combination with enzyme activity threshold in the CASH system.

[0005] To achieve the above objectives, the present invention provides a layered improvement structure for saline-alkali land covered with sand and peat, which includes, from top to bottom, a layer of dead branches and fallen leaves, a mixed sand-peat layer, a peat layer and a mineral gleyed layer, with an irrigation pipe layer disposed in the mixed sand-peat layer and / or the peat layer.

[0006] The mass ratio of sand and peat in the sand-peat mixed layer is 3-5:1, the particle size of the sand is 0.1-0.5 mm, and the organic matter content of the peat is 30-50%.

[0007] The irrigation pipeline layer includes a main water supply pipe and an auxiliary pipe. The main water supply pipe is connected to the auxiliary pipe, and a microbial modifier solution or humic acid solution is applied to the auxiliary pipe.

[0008] Preferably, the fallen leaves and branches covering the ground includes naturally fallen or artificially laid plant debris, with a thickness of 5-8 cm.

[0009] Preferably, the thickness of the sand-peat mixture layer is 6-12cm, the peat soil is Altai Mountain herbaceous peat, the peat soil is in 10-20cm blocks, and the pH is 5.5-7.0.

[0010] Preferably, the peat layer comprises unbroken Altai herbaceous peat, the pores of which are filled with a sand-peat mixture, the carbon-nitrogen ratio of which is 20-30, and the thickness is 40-60 cm.

[0011] Preferably, the mineral gleyed layer is obtained by mixing peat soil and native soil layer, with a thickness of 20-30cm.

[0012] The above-mentioned method for improving and regulating the structure of saline-alkali land with sand-peat stratification includes the following steps:

[0013] S1. Crush the Altai Mountain herbaceous peat into 10-20cm blocks. After sieving the sand, check the particle size until it meets the standard and set it aside. Spread the plant residue evenly and spray with wood vinegar to promote decomposition.

[0014] S2. Place the blocky Altai Mountain herbaceous peat on top of the original soil layer, and use a deep tillage machine to mix the Altai Mountain herbaceous peat with the original soil layer to obtain a mineral gleyed layer.

[0015] S3. Arrange the unbroken Altai Mountain herbaceous peat in an alternating pattern on the mineral gleyed layer to obtain a peat layer. The irrigation pipe layer is partially located in the peat layer.

[0016] S4. Mix the blocky Altai Mountain herbaceous peat and sand in a mixer according to the mass ratio, and spread it evenly on top of the peat layer and the irrigation pipe layer. While spreading, compact it to a porosity of 45-50% to obtain a sand-peat mixed layer.

[0017] S5. Based on the Cornell Soil Health Assessment System, conduct health diagnosis of the improved structure, and adjust the thickness of the sand-peat mixture layer according to the porosity score. When the porosity score is below 55, increase the thickness of the sand-peat mixture layer by 1-2 cm. When the enzyme activity score is below 80, add microbial amendments through the irrigation pipe layer.

[0018] S6. Evenly spread the decomposed plant residues on top of the sand-peat mixture layer to obtain a layer of dead branches and fallen leaves.

[0019] Preferably, in S1, the plant residue includes straw, dead branches and leaves with a particle size of less than 3 cm, and the concentration of wood vinegar is 0.1%.

[0020] Preferably, in S1, the influent swelling rate of Altai Mountain herbaceous peat is 5-15%, the soluble organic carbon (DOC) of Altai Mountain herbaceous peat is 80-120 mg / kg, and the DOC of sandy soil is 1-5 mg / kg.

[0021] Preferably, in S5, the microbial modifier includes microbial synergistic nitrogen-fixing bacteria and phosphorus lysing agent mixed in a mass ratio of 2-3:1.

[0022] Preferably, in S5, before planting crops in the improved structure, the improved structure is assessed for health using the Cornell Soil Health Assessment System, and porosity and enzyme activity are tested.

[0023] Therefore, the present invention employs the above-mentioned method for improving the structure and regulating the layering of sand-peat on saline-alkali land, and its beneficial effects are as follows:

[0024] 1. This invention achieves salt retention, water conservation and nutrient regulation through a sand-peat mixed layer. At the same time, it combines the Cornell Soil Health Assessment System (CASH) to dynamically optimize the thickness of the sand-peat mixed layer, which can be extended to ecological restoration projects (such as vegetation reconstruction in desertification edge areas) and precision agricultural management.

[0025] 2. This invention optimizes water and salt transport and organic matter distribution by designing a layered structure of sand-peat, which includes a dead leaf cover layer, a sand-peat mixed layer, a peat layer and a mineral gleyed layer. This induces an increase in the activity of native soil microorganisms, and the improvement effect is dynamically evaluated by combining the enzyme activity threshold in the CASH system.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a layered improvement structure for saline-alkali land covered with sand and peat, according to the present invention.

[0028] Figure label:

[0029] 1. Dead leaves and branches cover layer; 2. Sand-peat mixed layer; 3. Peat layer; 4. Mineral gleyed layer. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0031] Example 1

[0032] like Figure 1 As shown (arrows indicate water transport paths, dashed arrows indicate water infiltration directions; the sand-peat mixture layer infiltrates rapidly, while the peat layer stores water slowly), this invention provides a sand-peat layered improvement structure for saline-alkali land, suitable for arid saline-alkali land with annual precipitation ≤50mm. The improvement structure, from top to bottom, includes a fallen leaf and twig cover layer 1, a sand-peat mixture layer 2, a peat layer 3, and a mineral-rich gleyed layer 4. An irrigation pipe layer is located at the interface between the sand-peat mixture layer 2 and the peat layer 3. The fallen leaf and twig cover layer 1 reduces evaporation and lowers the salt return pressure of the sand-peat mixture layer 2. The sand-peat mixture layer 2 adsorbs surface salts, which infiltrate through pores into the peat layer 3 and are discharged through the large pores of the peat layer 3. The organic acids produced by the decomposition of peat layer 3 are slowly released through the mineral-rich gleyed layer 4, neutralizing the alkalinity of the underlying soil. The solution from the irrigation pipe layer diffuses through the pores of the sand-peat mixture layer 2 and the peat layer 3, acting simultaneously on each layer and improving the improvement efficiency.

[0033] The fallen leaves and branches mulch layer 1 consists of naturally fallen or artificially laid plant debris, with a thickness of 5-8 cm. The fallen leaves and branches mulch layer 1 reduces surface evaporation through physical shading, thereby lowering the evaporation rate and preventing the underlying salts from rising with the moisture. After decomposition, it provides an organic carbon source.

[0034] The thickness of the sand-peat mixed layer 2 is 6-12cm. The peat soil is Altai Mountain herbaceous peat, and the peat soil is in 10-20cm lumps with a pH of 5.5-7.0.

[0035] In the sand-peat mixed layer 2, the mass ratio of sand to peat is 3-5:1. The sand particle size is 0.1-0.5 mm, and the organic matter content of the peat is 30-50%. The sand particles encapsulate the peat fibers, forming a granular structure with a porosity ≥45%. Peat significantly optimizes water retention, acidifies the soil, increases the organic carbon pool, and improves desalination efficiency.

[0036] Sandy soil provides aeration, while peat moss adsorbs salts and releases nutrients through colloids. When mixed, they form a balanced structure of aeration and fertilizer retention, allowing irrigation water to penetrate quickly and adsorbing salt ions. With a porosity of 45%-50%, this avoids the anaerobic environment caused by insufficient aeration in peat layer 3, while also preventing the problem of poor fertilizer retention in sandy soil.

[0037] The peat layer 3 consists of unbroken Altai herbaceous peat, and the pores of the Altai herbaceous peat are filled with a sand-peat mixture layer 2. The carbon-nitrogen ratio of the Altai herbaceous peat is 20-30, and the thickness is 40-60 cm.

[0038] Unbroken Altai Mountain herbaceous peat moss is arranged in an interwoven pattern, forming a macropore-micropore composite structure. The macropores facilitate drainage and salt removal, while the micropores retain water through capillary action. The carbon-to-nitrogen ratio of Altai Mountain herbaceous peat moss is 20-30, providing an ideal environment for microorganisms. Its organic acids neutralize soil alkalinity while slowly releasing nutrients. It continuously releases nitrogen, phosphorus, and potassium, regulating the pH of the buffered saline-alkali soil to 6.5-7.5.

[0039] Mineral gleyed layer 4 is formed by mixing peat soil and native soil, with a thickness of 20-30 cm. After the Altai Mountain herbaceous peat is mixed with the native soil, the colloidal action of the Altai Mountain herbaceous peat binds the native soil particles, improving the compaction of the native soil. At the same time, this layer has a higher density than peat layer 3, promoting capillary fracture and blocking the upward infiltration of salts carried by the underlying groundwater.

[0040] The irrigation pipeline layer includes a main water supply pipe and auxiliary pipes, which are connected. The auxiliary pipes are spaced 30-50 cm apart, and a microbial amendment solution or humic acid solution is applied to them. The irrigation pipeline layer uses pressure-compensated drippers spaced 30 cm apart. The main water supply pipe provides irrigation water (EC value ≤ 1.2 dS / m). A microbial amendment or humic acid solution is injected into the main water supply pipe via a fertilizer pump, and then sprayed through the auxiliary pipes into the root zone of the plants within the improved structure. The microbial amendment activates soil enzyme activity, while the humic acid solution (concentration 1%-3%) enhances the colloidal adsorption capacity of peat, achieving synergistic improvement through water, chemical, and biological processes.

[0041] Example 2

[0042] Example 1 describes a method for improving and regulating the structure of saline-alkali land with sand-peat stratification, which includes the following steps:

[0043] S1. Crush the Altai Mountain herbal peat into 10-20cm blocks. After sieving the sand, check the particle size until it meets the standards before use. The water expansion rate of Altai Mountain herbal peat is 5-15%, and the DOC of Altai Mountain herbal peat is 80-120mg / kg, while the DOC of sand is 1-5mg / kg. Crushing the peat into 10-20cm blocks preserves its porous structure and facilitates mixing. Sieving the sand controls the particle size and ensures aeration.

[0044] After evenly spreading the plant residues, spray with a 0.1% wood vinegar solution to promote decomposition. The plant residues include straw, dead branches, and leaves with a particle size of less than 3 cm. The plant residues decompose under the influence of the wood vinegar solution, releasing organic acids and nutrients, further regulating the pH of the topsoil, and providing a carbon source for microbial activity.

[0045] S2. Place the blocky Altai Mountain herbaceous peat on top of the original soil layer, and use a subsoiler to mix the Altai Mountain herbaceous peat with the original soil layer to obtain the mineral gleyed layer 4. The subsoiler mixes the Altai Mountain herbaceous peat with the original soil layer. The organic matter of the Altai Mountain herbaceous peat can bind the original soil particles and reduce the soil bulk density.

[0046] S3. Unbroken Altai Mountain herbaceous peat blocks are arranged alternately on the mineral gleyed layer 4 to form peat layer 3. The irrigation pipe layer is partially located within peat layer 3. The alternating arrangement of unbroken Altai Mountain herbaceous peat blocks forms a three-dimensional porous network. Large pores are used for drainage, allowing salt to be discharged with the water. Small pores retain water, holding 2-3 times their own weight in water. The high organic matter content of Altai Mountain herbaceous peat provides a habitat for microorganisms, gradually improving soil fertility.

[0047] S4. Mix blocky Altai Mountain herbaceous peat and sand in a mixer at a mass ratio of 3:1, and spread it evenly on top of the peat layer 3 and the irrigation pipe layer. While spreading, compact it to a porosity of 45-50% to obtain the sand-peat mixed layer 2.

[0048] After compaction, the porosity of the mixed sand and Altai Mountain herbaceous peat is stabilized at 45%-50%. The sand ensures air circulation, while the Altai Mountain herbaceous peat adsorbs surface salts and provides near-root nutrients to the plants. The compaction process reduces later settling and maintains structural stability.

[0049] S5. Based on the CASH system, dynamically monitor the improved structure and adjust the thickness of the sand-peat mixture layer 2 according to the porosity score. When the porosity score is below 55, increase the thickness of the sand-peat mixture layer 2 by 1-2 cm. When the enzyme activity score is below 80, add microbial amendments through the irrigation pipe layer. The microbial amendments include nitrogen-fixing bacteria and phosphate-solubilizing agents. The nitrogen-fixing bacteria and phosphate-solubilizing agents in the microbial amendments can improve nutrient conversion efficiency, and humic acid enhances the adsorption capacity of peat.

[0050] The CASH system monitors porosity and aminopeptidase activity in real time. Porosity reflects air permeability, and enzyme activity reflects microbial activity. When the porosity score is low, the thickness of the mixing layer is increased to enhance air permeability; when enzyme activity is low, a microbial modifier is added to activate biological activity.

[0051] S6. Evenly spread decomposed plant residues on top of the sand-peat mixture layer 2 to obtain the fallen leaves and branches cover layer 1. The decomposed plant residues cover the ground surface, reducing evaporation and salt uplift through physical shading. At the same time, the residues continue to decompose, releasing organic acids and nutrients, regulating the surface pH value, and providing a mild growth environment for plant seedlings.

[0052] Example 3

[0053] The difference between this embodiment and embodiment 2 is that the mass ratio of blocky Altai Mountain herbaceous peat and sandy soil is 4:1, while the rest is the same as in embodiment 2.

[0054] Example 4

[0055] The difference between this embodiment and embodiment 2 is that the mass ratio of blocky Altai Mountain herbaceous peat and sandy soil is 5:1, while the rest is the same as in embodiment 2.

[0056] Comparative Example 1

[0057] The difference between this comparative example and Example 2 is that no Altai Mountain herbal peat was added; otherwise, they are the same as in Example 2.

[0058] Test Example 1

[0059] The indices of the improved structures in Example 2 and Comparative Example 1 were analyzed, and the results are shown in Table 1.

[0060] Table 1. Performance indicators of the improved structures in Example 2 and Comparative Example 1

[0061]

[0062]

[0063] As can be seen from the data in Table 1, the addition of Altai Mountain vegetation peat significantly optimizes water retention, acidifies soil, increases organic carbon pool, and improves desalination efficiency, achieving a systematic improvement in physical, chemical, and biological properties.

[0064] Therefore, this invention adopts the above-mentioned sand-peat stratified improvement structure and improvement regulation method for saline-alkali land. Through the design of the sand-peat stratified structure, a dead leaf cover layer, a sand-peat mixed layer, a peat layer and a mineral gleyed layer are set up respectively to optimize water and salt transport and organic matter distribution, induce the improvement of soil native microbial activity, and dynamically evaluate the improvement effect in combination with the enzyme activity threshold in the CASH system.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A layered improvement structure for saline-alkali land covered with sand and peat, characterized in that: From top to bottom, it includes a layer of dead branches and leaves, a mixed sand-peat layer, a peat layer, and a mineral gleyed layer. The irrigation pipe layer is set in the mixed sand-peat layer and / or the peat layer. The mass ratio of sand and peat in the sand-peat mixed layer is 3-5:1, the particle size of the sand is 0.1-0.5 mm, and the organic matter content of the peat is 30-50%. The irrigation pipeline layer includes a main water supply pipe and an auxiliary pipe. The main water supply pipe is connected to the auxiliary pipe, and a microbial modifier solution or humic acid solution is applied to the auxiliary pipe.

2. The layered improvement structure of saline-alkali land covered with sand and peat as described in claim 1, characterized in that: The fallen leaves and branches mulch layer includes naturally fallen or artificially laid plant debris, with a thickness of 5-8 cm.

3. The layered improvement structure of saline-alkali land covered with sand and peat as described in claim 1, characterized in that: The sand-peat mixture layer is 6-12cm thick, the peat soil is Altai Mountain herbaceous peat, the peat soil is in 10-20cm lumps, and the pH is 5.5-7.

0.

4. The layered improvement structure of saline-alkali land covered with sand and peat as described in claim 1, characterized in that: The peat layer consists of unbroken Altai herbaceous peat, with pores filled by a sand-peat mixture. The carbon-nitrogen ratio of the Altai herbaceous peat is 20-30, and the thickness is 40-60 cm.

5. The layered improvement structure of saline-alkali land covered with sand and peat as described in claim 1, characterized in that: The mineral gleyed layer is formed by mixing peat soil and native soil, and has a thickness of 20-30 cm.

6. The method for improving and regulating the layered structure of saline-alkali land covered with sand and peat as described in any one of claims 1-5, characterized in that: Includes the following steps: S1. Crush the Altai Mountain herbaceous peat into 10-20cm blocks. After sieving the sand, check the particle size until it meets the standard and set it aside. Spread the plant residue evenly and spray with wood vinegar to promote decomposition. S2. Place the blocky Altai Mountain herbaceous peat on top of the original soil layer, and use a deep tillage machine to mix the Altai Mountain herbaceous peat with the original soil layer to obtain a mineral gleyed layer. S3. Arrange the unbroken Altai Mountain herbaceous peat in an alternating pattern on the mineral gleyed layer to obtain a peat layer. The irrigation pipe layer is partially located in the peat layer. S4. Mix the blocky Altai Mountain herbaceous peat and sand in a mixer according to the mass ratio, and spread it evenly on top of the peat layer and the irrigation pipe layer. While spreading, compact it to a porosity of 45-50% to obtain a sand-peat mixed layer. S5. Based on the Cornell Soil Health Assessment System, conduct health diagnosis of the improved structure, and adjust the thickness of the sand-peat mixture layer according to the porosity score. When the porosity score is below 55, increase the thickness of the sand-peat mixture layer by 1-2 cm. When the enzyme activity score is below 80, add microbial amendments through the irrigation pipe layer. S6. Evenly spread the decomposed plant residues on top of the sand-peat mixture layer to obtain a layer of dead branches and fallen leaves.

7. The method for improving and regulating the layered structure of saline-alkali land covered with sand and peat as described in claim 6, characterized in that: In S1, the plant residues include straw, dead branches and leaves with a particle size of less than 3 cm, and the concentration of wood vinegar is 0.1%.

8. The method for improving and regulating the layered structure of saline-alkali land covered with sand and peat as described in claim 6, characterized in that: In S1, the influent swelling rate of Altai Mountain herbaceous peat is 5-15%, the DOC of Altai Mountain herbaceous peat is 80-120 mg / kg, and the DOC of sandy soil is 1-5 mg / kg.

9. The method for improving and regulating the layered structure of saline-alkali land covered with sand and peat as described in claim 6, characterized in that: In S5, the microbial modifier includes microbial synergistic nitrogen-fixing bacteria and phosphorus lysing agents mixed in a mass ratio of 2-3:

1.

10. The method for improving and regulating the layered structure of saline-alkali land covered with sand and peat as described in claim 6, characterized in that: In S5, before planting crops in the improved structure, the improved structure is assessed using the Cornell Soil Health Assessment System, which includes testing porosity and enzyme activity.

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