A method for improving saline-alkali land in semi-arid areas to enhance plant diversity

Abstract

This invention discloses a method for improving saline-alkali land in semi-arid regions to enhance plant diversity, comprising the following steps: S1, construction of treatment units; S2, arrangement of treatment units; S3, preliminary soil treatment; S4, planting of plants; and S5, intensive soil treatment. This invention addresses the problems of high salinity and species scarcity in saline-alkali land in semi-arid regions, providing a complete treatment method. By deploying multiple treatment units to form a treatment system, combined with the soil conditioner specifically designed for this invention, the high salinity of saline-alkali soil in semi-arid regions can be alleviated. Simultaneously, by incorporating a phytoremediation system primarily composed of alkali plantations, the biodiversity of exposed saline-alkali land in semi-arid regions can be effectively enhanced. Furthermore, considering seasonal factors and other factors such as rainfall, a one-year treatment plan is ultimately developed. After treatment, the land can be selectively developed into ornamental wetlands or agricultural land, possessing significant economic value.

Description

Technical Field

[0001] This invention relates to the field of soil ecological improvement technology, specifically to a method for improving saline-alkali land in semi-arid areas to enhance plant diversity. Background Technology

[0002] Saline-alkali land is a type of salt accumulation, referring to soil where the salt content affects the normal growth of crops. The formation of alkaline soil and alkalized soil is mostly related to the accumulation of carbonates in the soil, resulting in a generally high degree of alkalization. In severe saline-alkali land, plants can hardly survive.

[0003] The main methods for managing saline-alkali land include physical management, chemical management, biological management, and integrated management measures.

[0004] Physical remediation measures: These involve physical methods to improve saline-alkali soil, such as sand covering, deep plowing and tilling, and surface mulching. Sand covering involves covering saline-alkali land with loose, porous materials such as blast furnace slag or coal ash to reduce soil salinity and alkalinity, thereby improving soil fertility. Deep plowing and tilling deepen the soil layers, promote the formation of soil aggregates, increase soil porosity, and enhance soil permeability.

[0005] Chemical remediation measures: Using soil conditioners such as gypsum and ferrous sulfate to reduce or eliminate soil alkalinity and improve soil physical and chemical properties. These chemical conditioners can improve soil structure and promote plant growth.

[0006] Biological management measures: Improve soil fertility, improve soil structure, improve farmland microclimate, reduce surface water evaporation, and inhibit salt return by planting salt-tolerant plants, afforestation, and applying microbial fertilizers.

[0007] Comprehensive management measures: Combining physical, chemical, and biological methods, and using various measures in a comprehensive manner according to specific circumstances to achieve the best improvement effect. For example, establishing a complete irrigation and drainage system, strengthening water management, strictly controlling the groundwater level, and leaching and removing salts from the soil through irrigation flushing, flood diversion and silt removal.

[0008] These treatment methods typically need to be selected and combined based on specific circumstances to achieve the best improvement results. Seasonal changes also have a significant impact on the salinity of saline-alkali land, but currently there is a lack of comprehensive treatment methods that take into account seasonal influences. Patent publication number CN108966718A discloses a method for improving saline-alkali land, including the following steps: A) deep plowing and leveling the saline-alkali land; B) implementing underground drainage of salt from the leveled saline-alkali land; C) irrigating the saline-alkali land after laying the underground drainage pipes; D) applying a soil conditioner to the treated saline-alkali land; E) planting salt-tolerant rice varieties. This method can significantly improve the physical structure of saline-alkali soil, reduce the total salt content, activate the soil, retain water and fertilizer, increase the organic matter content of the soil, and change the physicochemical properties of saline-alkali soil, thereby achieving a long-term virtuous cycle for saline-alkali soil. However, it does not consider the seasonal impact; for different seasons and salinity levels, actual treatment measures are unlikely to achieve the described effects, and there is also a lack of research on the plant diversity of saline-alkali land. Summary of the Invention

[0009] To address the aforementioned problems, this invention provides a method for improving saline-alkali land soil in semi-arid areas to enhance plant diversity.

[0010] The technical solution of this invention is:

[0011] A method for improving saline-alkali land in semi-arid areas to enhance plant diversity includes the following steps:

[0012] S1. Construction of treatment units: The bare land to be treated is divided into several treatment units. Within each treatment unit, from upstream to downstream, there are terrestrial plant planting areas, alkali-covered plant planting areas, and aquatic plant planting areas. A first drainage ditch is excavated on both sides and inside the terrestrial plant planting area, and a second drainage ditch is excavated on both sides and inside the alkali-covered plant planting area. The second drainage ditch is connected to the aquatic plant planting area.

[0013] S2. Arrangement of treatment units: Several treatment units are arranged in sequence in the longitudinal direction to form treatment unit strips. Several treatment unit strips are arranged in sequence in the transverse direction. At the same time, the alkali-covered canopy planting area and the aquatic plant planting area in two adjacent treatment unit strips are aligned with each other. Under the alkali-covered canopy planting area and the aquatic plant planting area, underground pipes perpendicular to the treatment unit strips are laid below.

[0014] S3. Preliminary soil treatment: From March to May, water is injected into the first drainage ditch of the upstreammost treatment unit in each treatment unit strip, so that the water depth of the aquatic plant planting area in each treatment unit is not less than 40%. Then, soil conditioner is mixed into the terrestrial plant planting area at a rate of 60-80 kg / mu.

[0015] S4. Planting: From March to May, and within 10 to 15 days after the completion of the preliminary soil treatment in S3, terrestrial plants are planted in the terrestrial plant planting area, alkali grass is planted in the alkali grass planting area, and aquatic plants are planted in the aquatic plant planting area. After 15 to 20 days, water is injected into the first drainage ditch of the upstream treatment unit in each treatment unit strip, so that the water depth in the aquatic plant planting area in each treatment unit is not less than 60%.

[0016] S5. Soil Enhancement Management: From June to September, local water replenishment and drainage, combined with rainfall, are used to maintain the water depth of the aquatic plant planting area in each management unit at 60-70%. From October to March of the following year, local water replenishment and drainage, combined with rainfall, are used to maintain the water depth of the aquatic plant planting area in each management unit at 20-30%.

[0017] While S3 to S5 are being carried out, the collected saline solution is discharged through underground pipes.

[0018] Furthermore, within one of the treatment units, the first drainage ditch located on both sides and the second drainage ditch located on both sides are connected to each other. There are 2 to 4 first drainage ditches inside the terrestrial plant planting area and 3 to 6 second drainage ditches inside the alkali-covered plant planting area, and the first drainage ditches and the second drainage ditches are arranged in an intersecting manner.

[0019] Explanation: By optimizing the number and direction of the first and second drainage ditches, the irrigation of the treatment unit is made more uniform, effectively carrying salt and facilitating subsequent salt accumulation and leaching.

[0020] Furthermore, the area ratio of the terrestrial plant planting area, the alkali grass planting area, and the aquatic plant planting area is 1:1 to 1.5:2 to 3, and the depth of the aquatic plant planting area is 30 to 40 cm.

[0021] Explanation: By optimizing the area of ​​each planting zone, the types and quantities of crops to be planted can be allocated more rationally.

[0022] Furthermore, each governance unit strip includes 5 to 20 governance units, and the number of governance unit strips is 3 to 10.

[0023] Explanation: By optimizing the number of treatment strips and the number of treatment units, irrigation and desalination effects can be guaranteed, and the transformation of subsequent treatment units can be facilitated.

[0024] Furthermore, the soil conditioner in S3 is a mixture of desulfurized gypsum, sheep manure, and modified biochar in a mass ratio of 1:1:2 to 3.

[0025] Note: Soil conditioners can be used to investigate the physical and chemical properties of soil, which is beneficial to crop growth.

[0026] Furthermore, the preparation method of the biochar is as follows: The reeds harvested in S5 are used as the biomass raw material for biochar. The harvesting period is divided into two phases: the first phase is the growth period from March to April, and the second phase is the end of the maturity period. The reeds harvested in both phases are mixed in a 1:1 mass ratio, cut into 1-3 cm segments, and soaked in a 30-40% sulfuric acid solution for 48±1 hours. After removal, they are washed with deionized water until the pH reaches 7±0.2, obtaining acidified reed segments. The acidified reed segments are dried in an oven at 50-60℃, and then pulverized. Acidified reed powder was obtained by sieving through a 0-120 mesh sieve. The acidified reed powder was then soaked in a Fe(NO3)3 solution with a molar concentration of 0.3-0.5, and the mass ratio of acidified reed powder to pure iron in the Fe(NO3)3 solution was adjusted to 20-25:1. After soaking for 12 hours, the mixture was placed in a high-pressure reactor and kept at 220-260°C for 4-6 hours under continuous N2 purging. The solid-liquid mixture was then removed, washed with anhydrous ethanol, and filtered to obtain solid powder. The solid powder was then dried in an oven at 45-55°C to obtain biochar.

[0027] Note: By optimizing the preparation method of biochar, not only can we utilize the reeds planted in the aquatic plant planting area to achieve on-site material sourcing, but also improve the biochar preparation method according to the characteristics of reeds and the needs of saline-alkali land management. Through acidification and iron-modified hydrothermal methods, the adsorption capacity and activity of biochar can be effectively improved for the high-salt environment in saline-alkali land.

[0028] Furthermore, in S4, the terrestrial plants are one or more of Siberian quinoa, saltwort, sedge, and reed, and the aquatic plants are reeds. The seed quantity for planting terrestrial plants, saltwort, and aquatic plants is 7-8 kg / mu, and the plant spacing between terrestrial plants and saltwort is maintained at 5-6 cm.

[0029] Note: By using Suaeda salsa as the main crop for soil improvement, supplemented by other terrestrial and aquatic plants, the environment of bare saline-alkali land can be effectively improved, thereby playing a positive role in improving plant diversity.

[0030] Furthermore, the underground pipe has a diameter of 100-120mm, the pipe body has micropores of 0.5-1mm, the material of the underground pipe is PVC or PE, the burial depth of the underground pipe is 1-2m, and filter material is laid on top of the underground pipe.

[0031] Note: By optimizing the characteristics of underground pipes, we can ensure that they can effectively collect water and have a sufficient service life.

[0032] Furthermore, each of the underground pipes extends beyond the treatment unit strips located on both sides at both ends, and a water pump is provided at one end of the underground pipe.

[0033] Note: By optimizing the length of the underground pipes, we can ensure that they can effectively collect the water from the accumulated salt.

[0034] The beneficial effects of this invention are:

[0035] (1) The present invention provides a method for improving soil in saline-alkali land in semi-arid areas to enhance plant diversity. This method addresses the problems of high salinity and lack of plant species in saline-alkali land in semi-arid areas. It provides a complete treatment method. By deploying multiple treatment units to form a treatment system, and using the soil conditioner of the present invention, it can alleviate the high salinity of soil in saline-alkali land in semi-arid areas. At the same time, it is equipped with a plant remediation system based on alkali plantations, which can further effectively improve the biodiversity of bare saline-alkali land in semi-arid areas. Based on the influence of seasonal factors and taking into account other factors such as rainfall, a treatment plan with a duration of one year is finally formed. After the treatment is completed, it can be selectively developed into ornamental wetlands or agricultural land, which has great economic value.

[0036] (2) The present invention provides a method for improving soil in saline-alkali land in semi-arid areas to enhance plant diversity. By using Suaeda salsa as the main crop and supplementing it with other terrestrial and aquatic plants, it can effectively improve the environment of bare saline-alkali land and thus play a good role in improving the plant diversity of subsequent plants. Furthermore, by optimizing the preparation method of biochar, it can not only utilize the reeds planted in the aquatic plant planting area to achieve on-site material sourcing, but also improve the biochar preparation method according to the characteristics of reeds and the needs of saline-alkali land management. Through acidification and iron-modified hydrothermal methods, the adsorption capacity and activity of biochar can be improved. Two harvests of reeds can ensure high cellulose content and control the growth rate of reeds in the aquatic plant planting area, which can effectively improve the high-salt environment in saline-alkali land. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the treatment unit strip distribution of a method for improving saline-alkali land in semi-arid areas to enhance plant diversity, according to the present invention.

[0038] Figure 2 This is a schematic diagram of the internal structure of the treatment unit of a method for improving saline-alkali land in semi-arid areas to enhance plant diversity, according to the present invention.

[0039] Figure 3 This is a schematic diagram of vegetation cover and plant diversity in various comparative experiments in an experimental example of a method for improving saline-alkali land in semi-arid areas to enhance plant diversity according to the present invention.

[0040] Figure 4This is a schematic diagram of soil physicochemical indicators from multiple comparative experiments in an experimental example of a method for improving saline-alkali land in semi-arid areas to enhance plant diversity, according to the present invention.

[0041] Figure 5 This invention relates to an experimental example of a method for improving soil in saline-alkali land in semi-arid areas to enhance plant diversity. The method described in Example 1 was used to treat the bare land condition of saline-alkali land in semi-arid areas before the soil was cleared.

[0042] Figure 6 This invention relates to an experimental example of a method for improving soil in saline-alkali land in semi-arid areas to enhance plant diversity. The bare land condition in the saline-alkali land in the semi-arid area was treated according to the method in Example 1.

[0043] Among them, 1-terrestrial plant planting area, 11-first drainage ditch, 2-alkali tar plant planting area, 21-second drainage ditch, 3-aquatic plant planting area, 4-underground pipe. Detailed Implementation

[0044] Example 1

[0045] A method for improving saline-alkali land in semi-arid areas to enhance plant diversity includes the following steps:

[0046] S1. Construction of Governance Units: The bare land to be treated is divided into several governance units, such as... Figure 2 As shown, within each treatment unit, from upstream to downstream, there are terrestrial plant planting area 1, alkali-covered plant planting area 2, and aquatic plant planting area 3. A first drainage ditch 11 is excavated on both sides and inside the terrestrial plant planting area 1, and a second drainage ditch 21 is excavated on both sides and inside the alkali-covered plant planting area 2. The second drainage ditch 21 is connected to the aquatic plant planting area 3. Within one treatment unit, the first drainage ditch 11 and the second drainage ditch 21 on both sides are connected to each other. There are two first drainage ditches 11 inside the terrestrial plant planting area 1 and three second drainage ditches 21 inside the alkali-covered plant planting area 2. The first drainage ditches 11 and the second drainage ditches 21 are arranged in an intersecting manner.

[0047] S2, Layout of governance units: such as Figure 1 As shown, 10 treatment units are arranged longitudinally to form treatment unit strips, and 5 treatment unit strips are arranged transversely. At the same time, the alkali plant planting area 2 and the aquatic plant planting area 3 in two adjacent treatment unit strips are aligned with each other. Under the alkali plant planting area 2 and the aquatic plant planting area 3, underground pipes 4 perpendicular to the treatment unit strips are laid. The area ratio of terrestrial plant planting area 1, alkali plant planting area 2 and aquatic plant planting area 3 is 1:1.3:2.5, and the depth of aquatic plant planting area 3 is 35cm.

[0048] S3. Preliminary Soil Treatment: In March, water is injected into the first drainage ditch 11 of the upstream treatment unit in each treatment unit strip to make the water depth of the aquatic plant planting area 3 in each treatment unit 50%. Then, soil conditioner is mixed into the terrestrial plant planting area 1 at a rate of 75 kg / mu. The soil conditioner is a mixture of desulfurized gypsum, sheep manure and modified biochar in a mass ratio of 1:1:2.

[0049] The preparation method of biochar is as follows: Reeds from S5 are harvested as biomass raw materials for biochar. The harvesting period is divided into two phases: the first phase is the growth period in March, and the second phase is at the end of the maturity period. The reeds harvested in both phases are mixed in a 1:1 mass ratio, cut into 2cm segments, and soaked in a 35% sulfuric acid solution for 48 hours. After removal, they are washed with deionized water until the pH reaches 7, yielding acidified reed segments. These acidified reed segments are then dried in an oven at 55℃ and subsequently pulverized through a 110-mesh sieve. The acidified reed powder was obtained by sieving. The acidified reed powder was soaked in a Fe(NO3)3 solution with a molar concentration of 0.4. The mass ratio of acidified reed powder to pure iron in Fe(NO3)3 solution was adjusted to 23:1. After soaking for 12 hours, the two were placed in a high-pressure reactor and kept at 240°C for 5 hours under continuous N2 purging. The solid-liquid mixture was removed, washed with anhydrous ethanol, and filtered to obtain solid powder. The solid powder was dried in an oven at 50°C to obtain biochar.

[0050] S4. Planting: In March, and within 10 days after the completion of the initial soil treatment in S3, terrestrial plants are planted in terrestrial plant planting area 1, alkali grass is planted in alkali grass planting area 2, and aquatic plants are planted in aquatic plant planting area 3. After 15 days, water is injected into the first drainage ditch 11 of the upstream treatment unit in each treatment unit strip, so that the water depth of aquatic plant planting area 3 in each treatment unit is 70%. The terrestrial plants are sedge and reed, and the aquatic plants are reeds. The seed usage for terrestrial plants, alkali grass, and aquatic plants is 7 kg / mu. The plant spacing of terrestrial plants and alkali grass is maintained at 5 cm.

[0051] S5. Soil Enhancement Management: From June to September, local water replenishment and drainage, combined with rainfall, are used to maintain the water depth of aquatic plant planting area 3 in each management unit at 62%. From October to March of the following year, local water replenishment and drainage, combined with rainfall, are used to maintain the water depth of aquatic plant planting area 3 in each management unit at 24%.

[0052] While S3 to S5 are being carried out, the collected saline solution is discharged through underground pipe 4. The underground pipe 4 has a diameter of 110mm, and the pipe body has 0.7mm micropores. The underground pipe 4 is made of PVC or PE and is buried at a depth of 1.5m. Filter media, which is 5mm ceramsite, is laid on top of the underground pipe 4. Both ends of each underground pipe 4 extend out of the treatment unit strips located on both sides. A water pump is installed at one end of the underground pipe 4.

[0053] Example 2

[0054] The difference between this embodiment and Embodiment 1 is that:

[0055] There are 3 first drainage ditches 11 inside the terrestrial plant planting area 1, and 4 second drainage ditches 21 inside the alkali plant planting area 2. The area ratio of terrestrial plant planting area 1, alkali plant planting area 2, and aquatic plant planting area 3 is 1:1:2. The depth of aquatic plant planting area 3 is 30cm. Each treatment unit strip includes 5 treatment units, and the number of treatment unit strips is 3.

[0056] Example 3

[0057] The difference between this embodiment and Embodiment 1 is that:

[0058] There are 4 first drainage ditches 11 inside the terrestrial plant planting area 1, and 6 second drainage ditches 21 inside the alkali-covered plant planting area 2. The area ratio of terrestrial plant planting area 1, alkali-covered plant planting area 2, and aquatic plant planting area 3 is 1:1.5:3. The depth of aquatic plant planting area 3 is 40cm. Each treatment unit strip includes 20 treatment units, and the number of treatment unit strips is 10.

[0059] Note: In the actual treatment process, the number of treatment strips and treatment units should be reasonably allocated according to the area size and salinity of the bare saline-alkali land. When the area of ​​bare saline-alkali land is large, the number and size of treatment units should be appropriately increased. When the salinity of the bare saline-alkali land is high, the area size of the alkali plantation area 2 and the aquatic plant planting area 3 should be appropriately increased, and the number of the first drainage ditch 11 and the second drainage ditch 21 should be appropriately increased to promote drainage effect and improve the salt leaching rate.

[0060] Example 4

[0061] The difference between this embodiment and Embodiment 1 is that:

[0062] The soil conditioner is a mixture of desulfurized gypsum, sheep manure, and modified biochar in a mass ratio of 1:1:3.

[0063] The preparation method of biochar is as follows: Reeds from S5 are harvested as biomass raw materials for biochar. The harvesting period is divided into two phases: the first phase is during the third month of growth, and the second phase is at the end of the maturity period. The reeds harvested from both phases are mixed in a 1:1 mass ratio, cut into 1cm segments, and soaked in a 30% sulfuric acid solution for 47 hours. After removal, they are washed with deionized water until the pH reaches 6.8, obtaining acidified reed segments. The acidified reed segments are dried in an oven at 50℃, and then pulverized over 100... The acidified reed powder was obtained by sieving through a mesh screen. The acidified reed powder was then soaked in a Fe(NO3)3 solution with a molar concentration of 0.3. The mass ratio of the acidified reed powder to the pure iron in the Fe(NO3)3 solution was adjusted to 20:1. After soaking for 12 hours, the mixture was placed in a high-pressure reactor and kept at 220°C for 4 hours under continuous N2 purging. The solid-liquid mixture was then removed, washed with anhydrous ethanol, and filtered to obtain solid powder. The solid powder was dried in an oven at 45°C to obtain biochar.

[0064] Example 5

[0065] The difference between this embodiment and Embodiment 1 is that:

[0066] The soil conditioner is a mixture of desulfurized gypsum, sheep manure, and modified biochar in a mass ratio of 1:1:3.

[0067] The biochar preparation method is as follows: Reeds from S5 are harvested as biomass raw materials for biochar. The harvesting period is divided into two phases: the first phase is during the fourth month of growth, and the second phase is at the end of the maturity period. The reeds harvested from both phases are mixed in a 1:1 mass ratio, cut into 3cm segments, and soaked in a 40% sulfuric acid solution for 49 hours. After removal, they are washed with deionized water until the pH reaches 7.2, yielding acidified reed segments. These acidified reed segments are then dried in an oven at 60℃, and subsequently pulverized using 120... The acidified reed powder was obtained by sieving through a mesh screen. The acidified reed powder was then soaked in a Fe(NO3)3 solution with a molar concentration of 0.5. The mass ratio of the acidified reed powder to the pure iron in the Fe(NO3)3 solution was adjusted to 25:1. After soaking for 12 hours, the mixture was placed in a high-pressure reactor and kept at 260°C for 6 hours under continuous N2 purging. The solid-liquid mixture was then removed, washed with anhydrous ethanol, and filtered to obtain solid powder. The solid powder was dried in an oven at 55°C to obtain biochar.

[0068] Example 6

[0069] The difference between this embodiment and Embodiment 1 is that:

[0070] The soil conditioner is a mixture of desulfurized gypsum, sheep manure, and modified biochar in a mass ratio of 1:1:2.

[0071] The preparation method of biochar is as follows: Reeds from S5 are harvested as biomass raw materials for biochar. The harvesting period is divided into two phases: the first phase is during the growth period in April, and the second phase is at the end of the maturity period. The reeds harvested in both phases are mixed in a 1:1 mass ratio, cut into 3cm segments, and soaked in a 33% sulfuric acid solution for 48 hours. After removal, they are washed with deionized water until the pH reaches 7, resulting in acidified reed segments. These acidified reed segments are then dried in an oven at 58℃ and subsequently pulverized through a 100-mesh sieve. The acidified reed powder was obtained by sieving. The acidified reed powder was then soaked in a Fe(NO3)3 solution with a molar concentration of 0.3. The mass ratio of the acidified reed powder to the pure iron in the Fe(NO3)3 solution was adjusted to 21:1. After soaking for 12 hours, the mixture was placed in a high-pressure reactor and kept at 250°C for 5 hours under continuous N2 purging. The solid-liquid mixture was then removed, washed with anhydrous ethanol, and filtered to obtain solid powder. The solid powder was dried in an oven at 47°C to obtain biochar.

[0072] Note: In Examples 4-6, the proportion of soil conditioner was adjusted according to the amount of reeds harvested in the aquatic plant planting area 3. When there were more reeds harvested, the amount of reeds used could be increased appropriately, that is, the content of modified biochar could be increased. However, the content of modified biochar should not be too high, otherwise it would lead to increased costs and waste of resources. At the same time, when preparing biochar, N2 was introduced at a flow rate of 100 mL / min for 30 min to keep the hydrothermal carbonization reaction process under an anaerobic state.

[0073] Example 7

[0074] The difference between this embodiment and Embodiment 1 is that:

[0075] S3. The initial soil treatment will be carried out in April, so that the water depth of aquatic plant planting area 3 in each treatment unit is 40%. Then, soil conditioner will be mixed into terrestrial plant planting area 1 at a rate of 60 kg / mu.

[0076] S4. Planting time is in April and May, and within 15 days after the completion of the initial soil treatment in S3, terrestrial plants are planted in terrestrial plant planting area 1, alkali grass is planted in alkali grass planting area 2, and aquatic plants are planted in aquatic plant planting area 3. After 20 days, water is injected into the first drainage ditch 11 of the upstream treatment unit in each treatment unit strip, so that the water depth of aquatic plant planting area 3 in each treatment unit is 60%. The terrestrial plants are Siberian quinoa and salt-clawed vine, and the aquatic plants are reeds. The seed usage for terrestrial plants, alkali grass, and aquatic plants is 8 kg / mu. The plant spacing of terrestrial plants and alkali grass is maintained at 6 cm.

[0077] S5. Soil enhancement treatment will be carried out from June to September. Local water replenishment and drainage will be combined with rainfall to maintain the water depth of aquatic plant planting area 3 in each treatment unit at 70%. From October to March of the following year, local water replenishment and drainage will be combined with rainfall to maintain the water depth of aquatic plant planting area 3 in each treatment unit at 30%.

[0078] Note: For S3 to S5, the month to start treatment should be reasonably selected according to the geographical location of the saline-alkali land. For example, in warmer climates, treatment can start earlier, while in colder climates, treatment can start later. In areas with high annual precipitation, treatment can also start earlier to avoid the impact of precipitation on plant cultivation.

[0079] Example 8

[0080] The difference between this embodiment and Embodiment 1 is that:

[0081] While S3 to S5 are being carried out, the collected saline solution is discharged through underground pipe 4. The underground pipe 4 has a diameter of 100mm, and the pipe body has 0.5mm micropores. The underground pipe 4 is made of PVC or PE and is buried at a depth of 1m. Filter media is laid on top of the underground pipe 4. Both ends of each underground pipe 4 extend out of the treatment unit strips located on both sides. A water pump is installed at one end of the underground pipe 4.

[0082] Example 9

[0083] The difference between this embodiment and Embodiment 1 is that:

[0084] While S3 to S5 are being carried out, the collected saline solution is discharged through underground pipe 4. The underground pipe 4 has a diameter of 120mm, and the pipe body has 1mm micropores. The underground pipe 4 is made of PVC or PE and is buried at a depth of 2m. Filter media is laid on top of the underground pipe 4. Both ends of each underground pipe 4 extend out of the treatment unit strips located on both sides. A water pump is installed at one end of the underground pipe 4.

[0085] Note: In Examples 8 and 9, the position of the underground pipe 4 is adjusted according to factors such as the rainfall in the area. For example, in areas with high rainfall or large areas of saline-alkali land, the laying depth of the underground pipe 4 is appropriately increased.

[0086] Experimental Example

[0087] Next, we will verify the feasibility of the method of the present invention through field experiments. We selected saline-alkali bare land in the retreat area of ​​inland lakes in a semi-arid plateau. After being arranged according to the S2 treatment units, each treatment unit has a 3m*4m area composed of terrestrial plant planting area 1 and alkali plant planting area 2. The direction of the treatment unit is perpendicular to the local prevailing wind direction (northwest wind). Fresh water is regularly irrigated during the seedling stage to ensure the water requirements for plant survival. After the vegetation cover is formed, the amount of water used for maintenance is gradually reduced. Plants with excessive growth in the planting area are thinned appropriately, and weeds are removed in a timely manner.

[0088] Meanwhile, we conducted horizontal comparisons within multiple independent governance units, as shown in Table 1.

[0089] Table 1 Configuration Method

[0090] Serial Number Configuration T1 Suaeda salsa + Siberian goosefoot T2 Suaeda + salt claw T3 Suaeda salsa + Siberian goosegrass + Reed T4 Suaeda salsa + Siberian quinoa + Salt-cured sedge + Cyperus rotundus T5 Suaeda salsa + Siberian goosefoot + desulfurized gypsum or sheep manure or biochar T6 Suaeda salsa + Siberian goosegrass + Reed + desulfurized gypsum or sheep manure or biochar T7 Example 1

[0091] Regularly investigate the vegetation cover, quantity, and diversity within the sample plots. Simultaneously, collect soil samples from sample plots under different treatments to investigate soil physicochemical properties and compare the differences in soil physicochemical properties under different remediation measures. Compare the remediation results, such as... Figure 3 and Figure 4 As shown, in Example 1, the highest vegetation cover, highest plant diversity, and lowest soil pH were obtained when multiple plants were planted in a mixed manner and desulfurized gypsum, sheep manure, and biochar were applied. This indicates that the method of the present invention can effectively improve the salinity of saline-alkali land and can effectively improve the plant diversity of saline-alkali land after treatment.

[0092] like Figure 5 and Figure 6 As shown in the comparison diagram of the treatment results in Example 1, it can be seen that after one year of treatment according to the method in Example 1, the plant species diversity in the bare saline-alkali land has increased significantly.

Claims

1. A method for improving saline-alkali land in semi-arid areas to enhance plant diversity, characterized in that, Includes the following steps: S1. Construction of treatment units: The bare land to be treated is divided into several treatment units. In each treatment unit, from upstream to downstream, there are terrestrial plant planting area (1), alkali plant planting area (2), and aquatic plant planting area (3). A first drainage ditch (11) is dug on both sides and inside the terrestrial plant planting area (1). A second drainage ditch (21) is dug on both sides and inside the alkali plant planting area (2). The second drainage ditch (21) is connected to the aquatic plant planting area (3). S2. Arrangement of treatment units: Several treatment units are arranged in sequence in the longitudinal direction to form treatment unit strips. Several treatment unit strips are arranged in sequence in the transverse direction. At the same time, the alkali plant planting area (2) and the aquatic plant planting area (3) in two adjacent treatment unit strips are aligned with each other. Underground pipes (4) perpendicular to the treatment unit strips are laid below the alkali plant planting area (2) and the aquatic plant planting area (3). Each treatment unit strip includes 5 to 20 treatment units. The number of treatment unit strips is 3 to 10. S3. Preliminary soil treatment: In March to May, water is injected into the first drainage ditch (11) of the upstream treatment unit in each treatment unit strip, so that the water depth of the aquatic plant planting area (3) in each treatment unit is not less than 40%. Then, soil conditioner is mixed into the terrestrial plant planting area (1) at a rate of 60-80 kg / mu. The soil conditioner in S3 is a mixture of desulfurized gypsum, sheep manure, and modified biochar in a mass ratio of 1:1:2~3. The biochar is prepared as follows: Reeds from S5 are harvested as biomass raw materials for the biochar. The harvesting period is divided into two phases: the first phase is the growing season (March-April), and the second phase is the end of the maturity period. The reeds harvested in both phases are mixed in a 1:1 mass ratio, cut into 1-3 cm segments, and soaked in a 30-40% sulfuric acid solution for 48±1 hours. After removal, they are washed with deionized water until the pH reaches 7±0.2, resulting in acidified reed segments. These acidified reed segments are then dried in an oven. The reed powder is dried at 50-60℃ and then pulverized through a 100-120 mesh sieve to obtain acidified reed powder. The acidified reed powder is soaked in a Fe(NO3)3 solution with a molar concentration of 0.3-0.5, and the mass ratio of acidified reed powder to pure iron in the Fe(NO3)3 solution is adjusted to 20-25:

1. After soaking for 12 hours, the reed powder is placed in a high-pressure reactor and kept at 220-260℃ for 4-6 hours under continuous N2 purging. The solid-liquid mixture is then removed, washed with anhydrous ethanol, and filtered to obtain solid powder. The solid powder is dried in an oven at 45-55℃ to obtain biochar. S4. Planting: In March to May, and within 10 to 15 days after the completion of the preliminary soil treatment in S3, terrestrial plants are planted in the terrestrial plant planting area (1), alkali grass is planted in the alkali grass planting area (2), and aquatic plants are planted in the aquatic plant planting area (3). After 15 to 20 days, water is injected into the first drainage ditch (11) of the upstream treatment unit in each treatment unit strip, so that the water depth of the aquatic plant planting area (3) in each treatment unit is not less than 60%. S5. Soil Enhancement Management: From June to September, local water replenishment and drainage are combined with rainfall to maintain the water depth of the aquatic plant planting area (3) in each management unit at 60-70%. From October to March of the following year, local water replenishment and drainage are combined with rainfall to maintain the water depth of the aquatic plant planting area (3) in each management unit at 20-30%. While S3~S5 are being carried out, the collected saline solution is discharged through underground pipe (4).

2. The method for improving saline-alkali land in semi-arid areas to enhance plant diversity according to claim 1, characterized in that, Within one of the treatment units, the first drainage ditch (11) located on both sides and the second drainage ditch (21) located on both sides are connected to each other. There are 2 to 4 first drainage ditches (11) inside the terrestrial plant planting area (1) and 3 to 6 second drainage ditches (21) inside the alkali plant planting area (2). The first drainage ditch (11) and the second drainage ditch (21) are arranged in an intersecting manner.

3. The method for improving saline-alkali land soil in semi-arid areas to enhance plant diversity according to claim 1, characterized in that, The area ratio of the terrestrial plant planting area (1), the alkali grass planting area (2), and the aquatic plant planting area (3) is 1:1~1.5:2~3, and the depth of the aquatic plant planting area (3) is 30~40cm.

4. A method for improving saline-alkali land in semi-arid areas to enhance plant diversity according to claim 1, characterized in that, The terrestrial plants in S4 are one or more of Siberian quinoa, saltwort, sedge, and reed, and the aquatic plants are reeds. The seed quantity for terrestrial plants, saltwort, and aquatic plants is 7-8 kg / mu. The plant spacing between terrestrial plants and saltwort should be 5-6 cm.

5. A method for improving saline-alkali land soil in semi-arid areas to enhance plant diversity according to claim 1, characterized in that, The underground pipe (4) has a diameter of 100~120mm, the pipe body of the underground pipe (4) is provided with micropores of 0.5~1mm, the material of the underground pipe (4) is PVC or PE, the burial depth of the underground pipe (4) is 1~2m, and filter material is laid on the top of the underground pipe (4).

6. A method for improving saline-alkali land soil in semi-arid areas to enhance plant diversity according to claim 1, characterized in that, Each of the underground pipes (4) extends beyond the treatment unit strips located on both sides at both ends, and a water pump is provided at one end of the underground pipe (4).

Images