Ecological restoration method for vegetation in saline-alkali soil in lake atrophy area

Abstract

The invention discloses a method for ecological restoration of saline-alkali soil vegetation in a lake atrophy area. The method comprises the following steps: S1, dividing a restoration area: S1-1, arranging sampling points; s1-2, collecting and detecting a sample; s1-3, analyzing a detection result; s2, repairing the near lake bare area; s3, repairing the suaeda salsa repairing area; and S4, restoring the wetland restoration area. According to the method, the lake atrophy area is subjected to detailed block division, so that the restoration policy is made more specifically, the block meeting the fertility requirement is subjected to cultivated land transformation, and the other blocks are subjected to ecological restoration by adopting corresponding methods, so that the ecological utilization of the lake atrophy area is improved, and the purpose of adjusting measures to local conditions is achieved; the method has certain guiding significance and economic value for ecological management of the lake atrophy area.

Description

Technical Field

[0001] The invention relates to the technical field of lake management, and in particular to a method for ecological restoration of saline-alkali land vegetation in a lake shrinking area. Background Art

[0002] Affected by global change, many regions are facing the risk of water shortage. Rising temperatures and changes in precipitation have led to dramatic changes in many inland lakes. Inland lakes, especially smaller ones, are more vulnerable to climate change and human activities than outflowing lakes. The shrinkage of lakes can easily cause a series of ecological problems such as water ecological imbalance, land salinization, and reduced biodiversity. Under certain extreme climate conditions, they may face the risk of disappearing completely.

[0003] The saline-alkali land generated by the shrinkage of lakes in arid areas is a new difficult site, which urgently needs to implement forest and grass vegetation restoration and adaptive management of climate change risks. Studies have shown that vegetation restoration, as a key measure to enhance the resilience of the ecosystem in lake shrinking areas, plays an important role in maintaining habitats, conserving soil, and protecting water quality. On the one hand, different vegetation restoration measures can affect the soil organic carbon pool, physical and chemical properties, microbial community composition, carbon and nitrogen cycle, etc. around the lake; on the other hand, changes in soil pH and nutrient content have positive feedback on the vegetation restoration process. Therefore, vegetation restoration and soil conservation are mutually reinforcing processes and play an important role in maintaining the stability of lake ecological functions. Different vegetation restoration patterns can promote changes in bacterial and fungal communities in the soil, thereby greatly promoting the soil nutrient transformation process; there are also reports that vegetation restoration can cause soil crust and soil surface microbial communities to undergo succession, triggering changes in soil microbial community functions and physical and chemical properties.

[0004] At present, the comprehensive management of shrinking lake areas is still imperfect. Generally, a large number of plants are planted along the lake shores. However, this not only fails to alleviate the continued shrinkage of the lakes, but also fails to make good use of the shrinking areas. Therefore, a scientific and reasonable comprehensive management method is needed to improve the ecological protection of shrinking lake areas. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention provides a method for ecological restoration of saline-alkali land vegetation in lake shrinking areas.

[0006] The technical solution of the present invention is:

[0007] A method for ecological restoration of saline-alkali land vegetation in a lake shrinking area comprises the following steps:

[0008] S1. Repair area division:

[0009] S1-1. Sampling point layout: a number of sampling point strips are laid out in a direction perpendicular to the lake shoreline in the lake shrinking area, and a number of sampling points are laid out at equal intervals on each of the sampling point strips to collect soil;

[0010] S1-2. Sample collection and testing: pH value and soil fertility testing of the soil collected at the sampling points;

[0011] S1-3. Analysis of test results: As the pH value increases gradually from the alkalinity of the soil perpendicular to the lake shrinking area to the outside, the pH values ​​of each sampling point on a sampling point strip are summarized and divided into three equal parts from low to high to obtain two threshold points. The first threshold point is close to the lake shoreline, and the second threshold point is far from the lake shoreline. The first threshold point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the near-lake bare area. The second threshold point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the alkali sedge restoration area. The outermost sampling point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the wetland restoration area.

[0012] S2. Restoration of bare areas near the lake:

[0013] S2-1. Block division: The near-lake bare area is divided into several first sub-blocks according to the sampling point strips;

[0014] S2-2, fertility judgment: If more than half of the sampling points in the first sub-block have soil fertility that meets the soil fertility standard of Level 1 of the national soil census, the first sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding;

[0015] S2-3, Ecological Restoration: If the fertility of the first sub-block does not meet the standard, the vegetation coverage rate of the first sub-block is optimized and the vegetation coverage rate of the first sub-block is calculated. If the vegetation coverage rate is greater than 30%, some vegetation is removed to ensure that the vegetation coverage rate is ≤30%. If the vegetation coverage rate is ≤20%, aquatic plants are planted in the first sub-block to ensure that the vegetation coverage rate is 20% < ≤30%;

[0016] S3. Restoration of Suaeda salsa restoration area:

[0017] S3-1. Block division: Divide the sampling point strips in the Suaeda salsa restoration area into several second sub-blocks;

[0018] S3-2, fertility judgment: If more than half of the sampling points in the second sub-block have soil fertility that meets the soil fertility standard of Level 2 of the national soil census, the second sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding;

[0019] S3-3, Ecological restoration: If the fertility of the second sub-block does not meet the standard, the vegetation coverage rate of the second sub-block is optimized and the vegetation coverage rate of the second sub-block is counted. If the vegetation coverage rate is greater than 50%, the vegetation of the second sub-block is allowed to grow naturally. If the vegetation coverage rate is ≤40%, alkali canopy is planted in the second sub-block to ensure that the vegetation coverage rate is less than 40%;

[0020] S4. Wetland restoration area restoration:

[0021] S4-1. Block division: Divide the sampling point strips in the wetland restoration area into several third sub-blocks;

[0022] S4-2, fertility judgment: If more than half of the sampling points in the third sub-block have soil fertility that meets the soil fertility standard of level 3 of the national soil census, the third sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding;

[0023] S4-3. Ecological restoration: If the fertility of the third sub-block does not meet the standard, the vegetation coverage rate of the third sub-block will be optimized and the vegetation coverage rate of the third sub-block will be counted. If the vegetation coverage rate is greater than 70%, the vegetation in the third sub-block will be allowed to grow naturally. If the vegetation coverage rate is ≤60%, aquatic plants will be planted in the third sub-block to ensure that the vegetation coverage rate is less than 60%.

[0024] Furthermore, the number of sampling point strips in S1 is 5 to 20, the number of sampling points on each sampling point strip is 9 to 30, the spacing between sampling point strips is 50 to 5000 m, the spacing between sampling points is 10 to 100 m, and the depth of soil collection is 5 to 20 cm.

[0025] Note: By setting up sampling points for sampling, we can understand the degree and trend of salinization in the entire shrinking area of ​​the lake, thus providing a theoretical basis for the subsequent formulation of relevant measures.

[0026] Furthermore, the aquatic plants in S2-3 and S4-3 are reed, reed, cattail, water candle, thorn grass, water plantain, etc.

[0027] Description: Planting aquatic plants can preserve species diversity in shrinking lake areas.

[0028] Furthermore, in S2-2, the soil fertility levels are divided as follows:

[0029] Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 1 of the national soil census are: organic matter>40g / kg, total nitrogen>2g / kg, total phosphorus>1g / kg, available phosphorus>40g / kg, total potassium>25g / kg. In step S2-2, when any two indicators at the sampling point reach level 1, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 1 of the national soil census.

[0030] Note: For bare areas near lakes, since they are relatively close to lakes, a higher fertility level is required to be worth developing into arable land. The purpose of selecting two fertility indicators is to choose suitable crops for planting based on the fertility corresponding to the indicators.

[0031] Furthermore, in S3-2, the soil fertility levels are classified as follows:

[0032] Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 2 of the national soil census are: 30g / kg<organic matter≤40g / kg, 1.5g / kg<total nitrogen≤2g / kg, 0.8g / kg<total phosphorus≤1g / kg, 20g / kg<available phosphorus≤40g / kg, 20g / kg<total potassium≤25g / kg. In step S3-2, when any 3 indicators at the sampling point reach level 2, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 2 of the national soil census.

[0033] Note: For the alkali sedge restoration area, the main planting is alkali sedge, supplemented by crops, so the number of fertility indicators required is more than that in the bare area near the lake.

[0034] Furthermore, in S4-2, the soil fertility levels are classified as follows:

[0035] Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 3 of the national soil census are: 20g / kg<organic matter≤30g / kg, 1g / kg<total nitrogen≤1.5g / kg, 0.6g / kg<total phosphorus≤0.8g / kg, 10g / kg<available phosphorus≤20g / kg, 15g / kg<total potassium≤20g / kg. In step S4-2, when any 4 indicators at the sampling point reach level 3, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 3 of the national soil census.

[0036] Note: For wetland restoration areas, which are far away from lakes, more arable land can be developed, but salinization is higher. The requirements for fertility indicators can be appropriately lowered, but more fertility indicators that meet the requirements should be selected, and the fertility of each block should be kept similar as much as possible, so that the same crops can be planted for easy management.

[0037] Furthermore, in S2-2, S3-2 and S4-2, after leveling and weeding, it is necessary to apply an enzyme for arable land to the soil, and the preparation method of the enzyme for arable land is as follows:

[0038] Mix fruits, stems and leaves of aquatic plants and water in a weight ratio of 1:2-3:10-15, place in a sealed container for fermentation for 90-100 days, and take the upper liquid to obtain enzyme for arable land;

[0039] The fruit is one or more of sea buckthorn, sand apple, apple pear, blueberry, plum, apricot, crisp date, and cantaloupe, and the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3;

[0040] In S2-2, after leveling and weeding, water is first added to the soil to keep the soil moisture content in the first sub-block at 50-60%, and then the arable land enzyme is mixed with animal manure and water in a weight ratio of 1:2:50 and added to the soil to increase the soil moisture content by 1-3%. Then, it is applied every 5-7 days, each time to increase the soil moisture content by 0.2-0.4%, and this is repeated for 5 times;

[0041] In S3-2, after leveling and weeding, water is first added to the soil to keep the soil moisture content in the second sub-block at 45-55%, and then the arable land enzyme is mixed with animal manure and water in a weight ratio of 1:2:80 and added to the soil to increase the soil moisture content by 2-4%. Then, it is applied every 5-7 days, each time to increase the soil moisture content by 0.5-1%, and this is repeated for 5 times;

[0042] In S3-2, after leveling and weeding, water is first added to the soil to keep the soil moisture content inside the third sub-block at 40-50%. Then, the arable land enzyme is mixed with animal manure and water in a weight ratio of 1:2:100 and added to the soil to increase the soil moisture content by 3-5%. Then, it is applied every 5-7 days, each time increasing the soil moisture content by 0.6-1.2%, and this is repeated for 5 times.

[0043] Note: Different proportions of enzymes for arable land are used in different areas. This is because the farther away from the lake, the higher the salinization, and the more enzymes are needed for arable land. At the same time, the initial moisture content of the bare area near the lake is high, so the amount applied each time should not be too high. The initial moisture content of the wetland restoration area is not high, and the area is large, so the amount applied each time can be appropriately increased.

[0044] Furthermore, in S3-3 and S4-3, before planting vegetation, a soil conditioner is applied to the soil, and the preparation method of the soil conditioner is:

[0045] The enzyme residue, aquatic plant stems and leaves and clay minerals are mixed in a weight ratio of 1:4-6:7-9, crushed and dried, and then passed through a 30-mesh sieve;

[0046] The enzyme residue is the lower layer residue produced when preparing the enzyme for cultivated land, the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3, and the clay mineral is kaolinite, montmorillonite, illite or sepiolite;

[0047] The application amount of the soil conditioner is 20-25 kg / mu.

[0048] Description: Soil conditioners can effectively improve the soil environment, which is beneficial to the activities of soil microorganisms and other organisms. Clay minerals can also reduce the content of heavy metals in the soil.

[0049] Furthermore, in S3-3, the Suaeda salsa is harvested every 3 to 6 months.

[0050] Note: Harvesting alkali can prevent the high-salt alkali residues from causing salt accumulation in the lake area.

[0051] The beneficial effects of the present invention are:

[0052] (1) The method for ecological restoration of saline-alkali land vegetation in a lake shrinking area of ​​the present invention divides the lake shrinking area into blocks in detail, so as to make a more targeted restoration policy. For blocks that meet the fertility requirements, arable land transformation is carried out, and for other blocks, corresponding methods are used for ecological restoration. This improves the ecological utilization of the lake shrinking area and realizes the principle of adapting measures to local conditions. It has certain guiding significance and economic value for the ecological management of the lake shrinking area.

[0053] (2) The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area of ​​the present invention controls the vegetation coverage rate in each divided area, thereby avoiding further loss of water resources and further shrinkage of the slope protection. In particular, the bare area near the lake needs to control the vegetation at a lower coverage rate to avoid excessive pressure on the water resources in the lake, while the area far away from the lake can choose a higher vegetation coverage rate. This is because the area can generally utilize relatively abundant groundwater resources and surface water resources. Increasing the vegetation coverage rate is conducive to improving the species diversity of the area.

[0054] (3) The method for ecological restoration of saline-alkali land vegetation in a lake shrinking area of ​​the present invention can help further repair and improve the soil that is about to be used as arable land through arable land enzymes, alleviate salinization, increase the organic matter content, and have a certain antibacterial effect. At the same time, part of the enzyme residue used to prepare arable land enzymes can be used as one of the raw materials for soil conditioners. While it is easy to obtain materials, it can also maximize the soil restoration effect in the wetland restoration area, and ultimately achieve the purpose of simultaneously promoting restoration in the near-lake bare area, the Salicornia repair area, and the wetland repair area. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A method for ecological restoration of saline-alkali land vegetation in a lake shrinking area according to the present invention is a schematic diagram of lake shrinking area division;

[0056] Figure 2 It is the correlation coefficient between the vegetation restoration effect and the soil pH value, nutrients, and particle size composition in an experimental example of a method for ecological restoration of saline-alkali land vegetation in a lake shrinking area of ​​the present invention;

[0057] Figure 3 It is a schematic diagram of an alkali canopy restoration area and a wetland restoration area in an experimental example of a method for ecological restoration of saline-alkali land vegetation in a lake shrinking area of ​​the present invention;

[0058] Figure 4 It is a schematic diagram of an alkali canopy restoration area and a bare area near a lake in an experimental example of a method for ecological restoration of saline-alkali land vegetation in a lake shrinking area of ​​the present invention.

[0059] Among them, 1-near lake bare area, 2-alkali canopy restoration area, 3-wetland restoration area. DETAILED DESCRIPTION

[0060] Example 1

[0061] A method for ecological restoration of saline-alkali land vegetation in a lake shrinking area comprises the following steps:

[0062] S1. Repair area division:

[0063] S1-1、Layout of sampling points: Figure 1 As shown, five sampling point strips were arranged perpendicular to the lake shoreline in the lake shrinking area, and 15 sampling points were evenly spaced on each sampling point strip for soil collection. The spacing between sampling point strips was 2000m, the spacing between sampling points was 60m, and the depth of soil collection was 10cm.

[0064] S1-2. Sample collection and testing: pH value and soil fertility testing of the soil collected at the sampling points;

[0065] S1-3. Analysis of test results: As the pH value increases gradually from the lake shrinking area to the outside due to the increased alkalinity of the soil, the pH value of each sampling point on a sampling point strip is summarized and divided into three equal parts from low to high to obtain two threshold points. The first threshold point is close to the lake shoreline, and the second threshold point is far from the lake shoreline. The first threshold point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the near-lake bare area 1. The second threshold point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the alkali sedge restoration area 2. The outermost sampling point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the wetland restoration area 3. Figure 1 As shown;

[0066] S2, restoration of bare area near the lake 1:

[0067] S2-1. Block division: The near-lake bare area 1 is divided into several first sub-blocks according to the sampling point strips;

[0068] S2-2, fertility judgment: If more than half of the sampling points in the first sub-block have soil fertility that meets the soil fertility standard of Level 1 of the national soil census, the first sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding;

[0069] Soil fertility levels are classified as follows:

[0070] Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 1 of the national soil census are: organic matter>40g / kg, total nitrogen>2g / kg, total phosphorus>1g / kg, available phosphorus>40g / kg, total potassium>25g / kg. In step S2-2, when any two indicators at the sampling point reach level 1, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 1 of the national soil census;

[0071] S2-3, Ecological Restoration: If the fertility of the first sub-block does not meet the standard, the vegetation coverage rate of the first sub-block will be optimized and the vegetation coverage rate of the first sub-block will be calculated. If the vegetation coverage rate is greater than 30%, some vegetation will be removed to ensure that the vegetation coverage rate is 30%. If the vegetation coverage rate is ≤20%, aquatic plants such as reeds, reeds, cattails, and water candles will be planted in the first sub-block to ensure that the vegetation coverage rate is 24%;

[0072] S3, Suaeda salsa restoration area 2 restoration:

[0073] S3-1, block division: divide the sampling point strip of Suaeda salsa restoration area 2 into several second sub-blocks;

[0074] S3-2, fertility judgment: If more than half of the sampling points in the second sub-block have soil fertility that meets the soil fertility standard of Level 2 of the national soil census, the second sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding;

[0075] Soil fertility levels are classified as follows:

[0076] Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 2 of the national soil census are: 30g / kg<organic matter≤40g / kg, 1.5g / kg<total nitrogen≤2g / kg, 0.8g / kg<total phosphorus≤1g / kg, 20g / kg<available phosphorus≤40g / kg, 20g / kg<total potassium≤25g / kg. In step S3-2, when any 3 indicators at the sampling point reach level 2, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 2 of the national soil census;

[0077] S3-3, Ecological restoration: If the fertility of the second sub-block does not meet the standard, the vegetation coverage rate of the second sub-block is optimized and the vegetation coverage rate of the second sub-block is counted. If the vegetation coverage rate is greater than 50%, the vegetation of the second sub-block is allowed to grow naturally. If the vegetation coverage rate is ≤40%, alkali sedge is planted in the second sub-block to ensure that the vegetation coverage rate reaches 45%, and the alkali sedge is harvested every 3 months.

[0078] S4, Wetland Restoration Area 3 Restoration:

[0079] S4-1, block division: divide the 3 sampling point strips in the wetland restoration area into several third sub-blocks;

[0080] S4-2, fertility judgment: If more than half of the sampling points in the third sub-block have soil fertility that meets the soil fertility standard of level 3 of the national soil census, the third sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding;

[0081] Soil fertility levels are classified as follows:

[0082] Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 3 of the national soil census are: 20g / kg<organic matter≤30g / kg, 1g / kg<total nitrogen≤1.5g / kg, 0.6g / kg<total phosphorus≤0.8g / kg, 10g / kg<available phosphorus≤20g / kg, 15g / kg<total potassium≤20g / kg. In step S4-2, when any 4 indicators at the sampling point reach level 3, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 3 of the national soil census;

[0083] S4-3, Ecological restoration: If the fertility of the third sub-block does not meet the standard, the vegetation coverage rate of the third sub-block will be optimized and the vegetation coverage rate of the third sub-block will be counted. If the vegetation coverage rate is greater than 70%, the vegetation of the third sub-block will be kept growing naturally. If the vegetation coverage rate is ≤60%, aquatic plants such as reeds, reeds, cattails and water candles will be planted in the third sub-block to ensure that the vegetation coverage rate reaches 65%;

[0084] In S2-2, S3-2 and S4-2, after leveling and weeding, it is necessary to apply the arable land enzyme to the soil. The preparation method of the arable land enzyme is as follows:

[0085] Mix fruits, aquatic plant stems and leaves and water in a weight ratio of 1:2.5:13, place in a sealed container and ferment for 95 days, and take the upper liquid to obtain enzyme for arable land;

[0086] The fruits are sea buckthorn and sand apple, and the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3;

[0087] In S2-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content in the first sub-block at 55%, and then the arable land enzyme was mixed with animal manure and water in a weight ratio of 1:2:50 and added to the soil to increase the soil moisture content by 2%. Subsequently, it was applied every 6 days, each time to increase the soil moisture content by 0.3%, and continued for 5 times;

[0088] In S3-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content in the second sub-block at 50%, and then the arable land enzyme was mixed with animal manure and water in a weight ratio of 1:2:80 and added to the soil to increase the soil moisture content by 3%. Subsequently, it was applied every 6 days, each time to increase the soil moisture content by 0.7%, and continued for 5 times;

[0089] In S3-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content in the third sub-block at 45%, and then the arable land enzyme was mixed with animal manure and water in a weight ratio of 1:2:100 and added to the soil to increase the soil moisture content by 4%. Subsequently, it was applied every 6 days, each time to increase the soil moisture content by 1%, and this was repeated for 5 times;

[0090] In S3-3 and S4-3, before planting vegetation, a soil conditioner is applied to the soil. The preparation method of the soil conditioner is as follows:

[0091] The enzyme residue, aquatic plant stems and leaves and clay minerals are mixed in a weight ratio of 1:5:8, crushed and dried, and then passed through a 30-mesh sieve;

[0092] The enzyme residue is the lower residue produced when preparing the enzyme for cultivated land, the aquatic plant stems and leaves are the aquatic plant stems and leaves harvested in S2-3 and S4-3, and the clay minerals are kaolinite and sepiolite;

[0093] The application amount of soil conditioner is 23kg / mu.

[0094] Example 2

[0095] The difference between this embodiment and embodiment 1 is that:

[0096] In S1-1, 10 sampling point strips were arranged perpendicular to the lake shoreline in the lake shrinkage area. Nine sampling points were evenly spaced on each sampling point strip for soil collection. The spacing between sampling point strips was 5000m, the spacing between sampling points was 100m, and the depth of soil collection was 20cm.

[0097] Example 3

[0098] The difference between this embodiment and embodiment 1 is that:

[0099] In S1-1, 20 sampling point strips were arranged perpendicular to the lake shoreline in the lake shrinkage area, and 30 sampling points were evenly spaced on each sampling point strip for soil collection. The spacing between sampling point strips was 50m, the spacing between sampling points was 10m, and the depth of soil collection was 5cm.

[0100] Note: According to the size of the shrinking area of ​​the lake to be repaired, just choose appropriate parameters.

[0101] Example 4

[0102] The difference between this embodiment and embodiment 1 is that:

[0103] In S2-3, if the vegetation coverage rate is ≤20%, aquatic plants such as reeds, trifoliate thorns and water plantain are planted in the first sub-block to ensure that the vegetation coverage rate is 30%.

[0104] Example 5

[0105] The difference between this embodiment and embodiment 1 is that:

[0106] In S3-3, if the vegetation coverage rate is ≤40%, then Suaeda salsa is planted in the second sub-block to ensure that the vegetation coverage rate reaches 50%, and the Suaeda salsa is harvested every 6 months.

[0107] Example 6

[0108] The difference between this embodiment and embodiment 1 is that:

[0109] In S4-3, if the vegetation coverage rate is ≤60%, aquatic plants such as reed, trifoliate thorn and water plantain are planted in the third sub-block to ensure that the vegetation coverage rate reaches 70%.

[0110] Example 7

[0111] The difference between this embodiment and embodiment 1 is that:

[0112] In S2-2, S3-2 and S4-2, after leveling and weeding, it is necessary to apply the arable land enzyme to the soil. The preparation method of the arable land enzyme is as follows:

[0113] Mix fruits, stems and leaves of aquatic plants and water in a weight ratio of 1:2:10, place in a sealed container and ferment for 90 days, and take the upper liquid to obtain enzyme for arable land;

[0114] The fruits are apples, pears and blueberries, and the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3;

[0115] In S2-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content in the first sub-block at 60%, and then the arable land enzyme was mixed with animal manure and water in a weight ratio of 1:2:50 and added to the soil to increase the soil moisture content by 1%. Subsequently, it was applied every 5 days, each time to increase the soil moisture content by 0.2%, and this was repeated for 5 times;

[0116] In S3-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content in the second sub-block at 55%, and then the arable land enzyme was mixed with animal manure and water in a weight ratio of 1:2:80 and added to the soil to increase the soil moisture content by 2%. Subsequently, it was applied every 5 days, each time to increase the soil moisture content by 0.5%, and continued for 5 times;

[0117] In S3-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content inside the third sub-block at 50%. Then, the arable land enzyme was mixed with animal manure and water in a weight ratio of 1:2:100 and added to the soil to increase the soil moisture content by 3%. Subsequently, it was applied every 5 days, each time increasing the soil moisture content by 0.6%, and this was repeated for 5 times.

[0118] Example 8

[0119] The difference between this embodiment and embodiment 1 is that:

[0120] In S2-2, S3-2 and S4-2, after leveling and weeding, it is necessary to apply the arable land enzyme to the soil. The preparation method of the arable land enzyme is as follows:

[0121] Mix fruits, aquatic plant stems and leaves and water in a weight ratio of 1:3:15, place in a sealed container and ferment for 100 days, and take the upper liquid to obtain the enzyme for arable land;

[0122] Among them, the fruits are plums, apricots, crisp dates and cantaloupe, and the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3;

[0123] In S2-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content in the first sub-block at 50%, and then the arable land enzyme was mixed with animal manure and water in a weight ratio of 1:2:50 and added to the soil to increase the soil moisture content by 3%. Subsequently, it was applied every 7 days, each time to increase the soil moisture content by 0.4%, and this was repeated for 5 times;

[0124] In S3-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content in the second sub-block at 45%, and then the arable land enzyme was mixed with animal manure and water in a weight ratio of 1:2:80 and added to the soil to increase the soil moisture content by 4%. Subsequently, it was applied every 7 days, each time to increase the soil moisture content by 1%, and this was repeated for 5 times;

[0125] In S3-2, after leveling and weeding, water was first added to the soil to keep the soil moisture content inside the third sub-block at 40%. Then, arable land enzymes were mixed with animal manure and water in a weight ratio of 1:2:100 and added to the soil to increase the soil moisture content by 5%. Subsequently, it was applied every 7 days, each time increasing the soil moisture content by 1.2%, and this was repeated for 5 times.

[0126] Note: If the initial moisture content in the block is relatively high, then when adding arable land enzymes, avoid increasing the moisture content too much and appropriately shorten the addition interval. If the initial moisture content in the block is relatively low, then when adding arable land enzymes, the moisture content can be further increased and the addition interval can be appropriately extended.

[0127] Example 9

[0128] The difference between this embodiment and embodiment 1 is that:

[0129] In S3-3 and S4-3, before planting vegetation, a soil conditioner is applied to the soil. The preparation method of the soil conditioner is as follows:

[0130] The enzyme residue, aquatic plant stems and leaves and clay minerals are mixed in a weight ratio of 1:4:7, crushed and dried, and then passed through a 30-mesh sieve;

[0131] The enzyme residue is the lower residue produced when preparing the enzyme for cultivated land, the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3, and the clay mineral is montmorillonite;

[0132] The application amount of soil conditioner is 20kg / mu.

[0133] Example 10

[0134] The difference between this embodiment and embodiment 1 is that:

[0135] In S3-3 and S4-3, before planting vegetation, a soil conditioner is applied to the soil. The preparation method of the soil conditioner is as follows:

[0136] The enzyme residue, aquatic plant stems and leaves and clay minerals are mixed in a weight ratio of 1:6:9, crushed and dried, and then passed through a 30-mesh sieve;

[0137] The enzyme residue is the lower residue produced when preparing the enzyme for cultivated land, the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3, and the clay mineral is illite;

[0138] The application amount of soil conditioner is 25kg / mu.

[0139] Experimental example

[0140] Next, we will conduct a field experiment on the method in Example 1 of the present invention with an actual case. The site is selected in the shrinking area of ​​Darinor Lake. The sampling points are arranged and samples are collected according to the method in S1. The near-lake bare area, the salsa alkali restoration area and the wetland restoration area are divided according to the pH value of the sampling points. The information of some points in each area is shown in the following table:

[0141] Table 1 Basic information of different ecological restoration areas

[0142]

[0143] We then calculated the average soil pH and soil nutrient content of the three ecological restoration areas, as shown in the following table:

[0144] Table 2 Average soil pH and soil nutrient content in different ecological restoration areas

[0145]

[0146] Subsequently, we conducted fertility judgments on each point in each ecological restoration area according to the fertility judgment methods in S2-2, S3-2, and S4-2, and found that: one block in the near-lake bare area 1 met the requirements for cultivated land, two blocks in the Suaeda restoration area 2 met the requirements for cultivated land, and one block in the wetland restoration area 3 met the requirements for cultivated land;

[0147] The soil pH value in the lake shrinking area is 10.30-10.68, which is strongly alkaline and severely saline-alkali land. The soil pH values ​​of various types of sample plots are as follows: wetland restoration area > Suaeda salsa restoration area > bare land near the lake, showing a trend of increasing with increasing distance from the lake shoreline and increasing altitude.

[0148] We then carried out restoration work in the corresponding ecological restoration areas according to the restoration methods in S2-3, S3-3 and S4-3, and counted the growth height of vegetation in each area after restoration. The results are shown in the following table:

[0149] Table 3 Vegetation growth status of different ecological restoration plots

[0150]

[0151] The soil pH value in the shrinking area of ​​Darinor Lake was positively correlated with the total carbon content, total nitrogen content, organic matter content, and silt content, with correlation coefficients (R) ranging from 0.26 to 0.47; it was negatively correlated with the sand content and vegetation coverage, with R being -0.26. Figure 2 As shown in the figure, vegetation coverage is positively correlated with soil organic matter content, total carbon content, total nitrogen content, and sand content, with R ranging from 0.22 to 0.63. Soil organic matter and total carbon content have a greater impact on vegetation coverage; it is negatively correlated with soil total sulfur content, total phosphorus content, pH value, and silt content, with correlation coefficients ranging from -0.21 to -0.53. The average plant height is positively correlated with soil total carbon, total nitrogen, organic matter, pH value, and sand content, with R ranging from 0.11 to 0.66. The main influencing factors of overall and vegetation coverage are similar.

[0152] As far as the Darinor Basin is concerned, rising temperatures and increased vegetation coverage are believed to have caused the lake to shrink to a certain extent, and the reduction in annual precipitation is consistent with the trend of lake shrinkage. Relevant studies have shown that the underground runoff of Darinor Lake is much greater than the surface runoff. Land evaporation is a key process connecting vegetation and groundwater. The intensity of evaporation increases with the increase of vegetation coverage. After relevant ecological restoration measures have been taken, remote sensing monitoring shows that while the vegetation coverage rate has increased, the trend of lake shrinkage has slowed down, which is also conducive to groundwater recharge. The ecological protection and restoration have achieved remarkable results. The method of the present invention has certain results.

[0153] At the same time, for the areas improved into arable land, taking the bare area 1 near the lake as an example, after applying arable land enzymes for improvement for about one month, the soil pH dropped from 10.3 to 7.76, and the soil salinization was greatly improved. The arable land enzymes contain a large amount of organic acids after fermentation, and also show strong acidic properties. After application to the soil, they can react with the alkaline components in the soil and effectively lower the soil pH. At the same time, the fruits selected for arable land enzymes, such as sea buckthorn and sand apple, are common fruits near the location of Darinor Lake.

[0154] For the soil that has been repaired with soil conditioners, taking wetland restoration area 3 as an example, the average plant height increased by 0.09m compared with the soil plots that have not been repaired with soil conditioners, indicating that the nutrients in the soil can effectively improve the soil environment, reduce the effectiveness of heavy metals, increase the diversity of organisms and microorganisms in the soil, and promote plant growth.

[0155] like Figure 3 and 4 As shown, after restoration, the regional division of the entire lake shrinkage area is very obvious. The vegetation coverage rate of wetland restoration area 3 behind Suaeda restoration area 2 meets the requirements, and the near-lake bare area 1 in front of Suaeda restoration area 2 near the lake is also covered with designated vegetation or improved into arable land.

Claims

1. A method for ecological restoration of saline-alkali land vegetation in lake shrinking areas, characterized in that: The following steps are involved: S1. Repair area division: S1-1. Sampling point layout: a number of sampling point strips are laid out in a direction perpendicular to the lake shoreline in the lake shrinking area, and a number of sampling points are laid out at equal intervals on each of the sampling point strips to collect soil; S1-2. Sample collection and testing: pH value and soil fertility testing of the soil collected at the sampling points; S1-3. Analysis of test results: As the pH value increases gradually from the alkalinity of the soil perpendicular to the lake shrinking area to the outside, the pH values ​​of each sampling point on a sampling point strip are summarized and divided into three equal parts from low to high to obtain two threshold points. The first threshold point is close to the lake shoreline, and the second threshold point is far from the lake shoreline. The first threshold point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the near-lake bare area (1). The second threshold point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the alkali sedge restoration area (2). The outermost sampling point on each sampling point strip is connected in sequence, and the enclosed lake shrinking area is used as the wetland restoration area (3). S2, Bare area near the lake (1) Restoration: S2-1. Block division: The near-lake bare area (1) is divided into several first sub-blocks according to the sampling point strips; S2-2, fertility judgment: If more than half of the sampling points in the first sub-block have soil fertility that meets the soil fertility standard of Level 1 of the national soil census, the first sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding; S2-3, Ecological Restoration: If the fertility of the first sub-block does not meet the standard, the vegetation coverage rate of the first sub-block is optimized and the vegetation coverage rate of the first sub-block is calculated. If the vegetation coverage rate is greater than 30%, some vegetation is removed to ensure that the vegetation coverage rate is ≤30%. If the vegetation coverage rate is ≤20%, aquatic plants are planted in the first sub-block to ensure that the vegetation coverage rate is 20% < ≤30%; S3, Suaeda salsa restoration area (2) Restoration: S3-1, block division: divide the sampling point strip of Suaeda salsa restoration area (2) into a number of second sub-blocks; S3-2, fertility judgment: If more than half of the sampling points in the second sub-block have soil fertility that meets the soil fertility standard of Level 2 of the national soil census, the second sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding; S3-3, Ecological restoration: If the fertility of the second sub-block does not meet the standard, the vegetation coverage rate of the second sub-block is optimized and the vegetation coverage rate of the second sub-block is counted. If the vegetation coverage rate is greater than 50%, the vegetation of the second sub-block is allowed to grow naturally. If the vegetation coverage rate is ≤40%, alkali canopy is planted in the second sub-block to ensure that the vegetation coverage rate is less than 40%; S4. Wetland restoration area (3) Restoration: S4-1, block division: divide the sampling point strip of the wetland restoration area (3) into several third sub-blocks; S4-2, fertility judgment: If more than half of the sampling points in the third sub-block have soil fertility that meets the soil fertility standard of level 3 of the national soil census, the third sub-block is considered to have fertility that meets the standard and can be used as arable land after leveling and weeding; S4-3. Ecological restoration: If the fertility of the third sub-block does not meet the standard, the vegetation coverage rate of the third sub-block will be optimized and the vegetation coverage rate of the third sub-block will be counted. If the vegetation coverage rate is greater than 70%, the vegetation in the third sub-block will be allowed to grow naturally. If the vegetation coverage rate is ≤60%, aquatic plants will be planted in the third sub-block to ensure that the vegetation coverage rate is less than 60%.

2. The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area according to claim 1, characterized in that: The number of sampling point strips in S1 is 5 to 20, the number of sampling points on each sampling point strip is 9 to 30, the spacing between sampling point strips is 50 to 5000 m, the spacing between sampling points is 10 to 100 m, and the depth of soil collection is 5 to 20 cm.

3. The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area according to claim 1, characterized in that: The aquatic plants in S2-3 and S4-3 are reed, reed, cattail, water candle, trifoliate thorn, water plantain and the like.

4. The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area according to claim 1, characterized in that: In S2-2, the soil fertility levels are divided as follows: Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 1 of the national soil census are: organic matter>40g / kg, total nitrogen>2g / kg, total phosphorus>1g / kg, available phosphorus>40g / kg, total potassium>25g / kg. In step S2-2, when any two indicators at the sampling point reach level 1, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 1 of the national soil census.

5. The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area according to claim 1, characterized in that: In S3-2, the soil fertility levels are divided as follows: Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 2 of the national soil census are: 30g / kg<organic matter≤40g / kg, 1.5g / kg<total nitrogen≤2g / kg, 0.8g / kg<total phosphorus≤1g / kg, 20g / kg<available phosphorus≤40g / kg, 20g / kg<total potassium≤25g / kg. In step S3-2, when any 3 indicators at the sampling point reach level 2, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 2 of the national soil census.

6. The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area according to claim 1, characterized in that: In S4-2, the soil fertility levels are classified as follows: Soil fertility detection includes 5 indicators: organic matter, total nitrogen, total phosphorus, available phosphorus and total potassium. The standards for the above 5 indicators to reach the soil fertility standard level 3 of the national soil census are: 20g / kg<organic matter≤30g / kg, 1g / kg<total nitrogen≤1.5g / kg, 0.6g / kg<total phosphorus≤0.8g / kg, 10g / kg<available phosphorus≤20g / kg, 15g / kg<total potassium≤20g / kg. In step S4-2, when any 4 indicators at the sampling point reach level 3, it can be considered that the soil fertility of the sampling point reaches the soil fertility standard level 3 of the national soil census.

7. The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area according to claim 1, characterized in that: In S2-2, S3-2 and S4-2, after leveling and weeding, it is necessary to apply an enzyme for arable land to the soil. The preparation method of the enzyme for arable land is as follows: Mix fruits, stems and leaves of aquatic plants and water in a weight ratio of 1:2-3:10-15, place in a sealed container for fermentation for 90-100 days, and take the upper liquid to obtain enzyme for arable land; The fruit is one or more of sea buckthorn, sand apple, apple pear, blueberry, plum, apricot, crisp date, and cantaloupe, and the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3; In S2-2, after leveling and weeding, water is first added to the soil to keep the soil moisture content in the first sub-block at 50-60%, and then the arable land enzyme is mixed with animal manure and water in a weight ratio of 1:2:50 and added to the soil to increase the soil moisture content by 1-3%. Then, it is applied every 5-7 days, each time to increase the soil moisture content by 0.2-0.4%, and this is repeated for 5 times; In S3-2, after leveling and weeding, water is first added to the soil to keep the soil moisture content in the second sub-block at 45-55%, and then the arable land enzyme is mixed with animal manure and water in a weight ratio of 1:2:80 and added to the soil to increase the soil moisture content by 2-4%. Then, it is applied every 5-7 days, each time to increase the soil moisture content by 0.5-1%, and this is repeated for 5 times; In S3-2, after leveling and weeding, water is first added to the soil to keep the soil moisture content inside the third sub-block at 40-50%. Then, the arable land enzyme is mixed with animal manure and water in a weight ratio of 1:2:100 and added to the soil to increase the soil moisture content by 3-5%. Then, it is applied every 5-7 days, each time increasing the soil moisture content by 0.6-1.2%, and this is repeated for 5 times.

8. The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area according to claim 7, characterized in that: In S3-3 and S4-3, before planting vegetation, a soil conditioner is applied to the soil, and the preparation method of the soil conditioner is as follows: The enzyme residue, aquatic plant stems and leaves and clay minerals are mixed in a weight ratio of 1:4-6:7-9, crushed and dried, and then passed through a 30-mesh sieve; The enzyme residue is the lower layer residue produced when preparing the enzyme for cultivated land, the stems and leaves of aquatic plants are the stems and leaves of aquatic plants harvested in S2-3 and S4-3, and the clay mineral is kaolinite, montmorillonite, illite or sepiolite; The application amount of the soil conditioner is 20-25 kg / mu.

9. The method for ecological restoration of saline-alkali land vegetation in a shrinking lake area according to claim 1, characterized in that: In S3-3, the Suaeda salsa is harvested every 3 to 6 months.

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