Vegetation recovery method for salinized desertification degraded grassland

Abstract

The invention relates to the technical field of saline desertification degraded land treatment, in particular to a vegetation recovery method for saline desertification degraded grassland. Comprising the following steps that S1, a planting pit unit is dug before winter comes, the planting pit unit comprises a plurality of triangular ditches, the trend of the triangular ditches is perpendicular to the perennial prevailing wind of a restored area, and a triangular ridge is formed between every two adjacent triangular ditches; s2, coconut fiber blanket strips are laid in the triangular ditches, and soil is pressed; s3, in the spring of the second year, the middle of the triangular ditch is filled with the improved material mixture, the coconut fiber blanket strips are pressed, the two sides of the coconut fiber blanket strips are tightly attached to the side faces of the triangular ditch, and the edges are exposed in the air; s4, the shrub seeds and the herbal seeds are mixed, soaked and then planted in the improved material mixture; and S5, sprinkling water so that the coconut fiber blanket strips are thoroughly wetted. The landform of the salinized and desertified degraded grassland is subjected to micro-transformation, the cost is low, the plant survival rate is high, and the vegetation recovery effect is good.

Description

Technical Field

[0001] The invention relates to the technical field of saline desertification and degraded land management, in particular to a method for restoring vegetation on saline desertification and degraded grassland. Background Art

[0002] The cold and arid regions have low temperatures, little precipitation, and heavy soil erosion. The grassland ecosystem is fragile and easily disturbed by natural and human factors. The vegetation coverage is low, and the grassland and cultivated land ecosystems are very fragile. The soil is very prone to salinization and sandiness. Soil salinization and desertification have become important obstacles to land productivity and are also one of the main factors of soil degradation and desertification in arid and semi-arid areas.

[0003] Currently, salinization and desertification are common in the Bashang area. The reasons for salinization are: (1) The annual average evaporation in the region is much greater than the annual average precipitation, with a long dry season and a short wet season, resulting in seasonal alternations between wet and dry seasons in rivers and lakes, which provides dynamic conditions for salt to move to the surface and accumulate; (2) The regional terrain is flat, the groundwater level is shallow, the water body is highly mineralized, the runoff is not smooth, the bottom bedrock is stable, and the structure is complete. Evaporation naturally becomes the main discharge channel for groundwater, and the salt in the groundwater continues to accumulate on the surface as the water evaporates; (3) ) Due to the control of the Mongolian high pressure and the influence of atmospheric circulation, northwest winds prevail all year round. Winds greatly promote soil salinization, which is mainly reflected in the fact that winds bring salt crystallized from saline-alkali land to the surface of non-salinized soil, while accelerating the evaporation of soil moisture, making salinization more serious; (4) The bedrock of the Bashang Plateau is mainly alkaline igneous rock, rich in alkaline minerals such as biotite, potassium feldspar, and pyroxene. The soil is rich in calcium carbonate, sodium chloride, sodium sulfate, etc., which provides the material basis for the formation of soil salinization.

[0004] The reasons for desertification are as follows: The soil in the Bashang area is mainly chestnut soil, dark chestnut soil and meadow chestnut soil. The first two types of soil are sandy and sandy loam, with loose structure, poor cohesion and are easily eroded by wind. The dynamic force of land sandy desertification is mainly manifested as the blowing and deflation action of wind, and only in the outfall sections of some rivers is it manifested as hydraulic erosion and scouring and silting action. The texture of the surface layer (tillage layer) of cultivated land soil is relatively coarse, with a large sand content and poor mechanical stability. At the same time, due to the dry, cold and windy climate, the mechanical weathering effect is strong, the calcium carbonate and soil organic matter content are low, and the soil structure stability is poor. The vegetation coverage rate is low in many areas, being low-coverage grasslands. The exposed areas are easily affected by the wind erosion effect, forming sandy desertified land. Traditional tillage methods loosen the soil after plowing, increasing the erodible particles on the soil surface. At the same time, due to the large undulation after tillage and the increase in turbulence, the wind erosion rate is often very high. The overlap of the fallow period and the windy and dry period leads to the fact that tillage activities increase the risk of sandy desertification formation. The windy and dry period in some parts of the Bashang area is from November to May of the following year, and the fallow period is from October to May of the following year, overlapping with each other. After the crops are harvested, the soil is exposed, and the soil moisture quickly dissipates. Coinciding with the windy period, the fine-grained substances in the soil are easily blown away, leaving behind coarser sand and gravel.

[0005] The saline-alkali and sandy desertified land has small soil moisture content, low fertility, sparse vegetation, few plant species, mostly drought-tolerant and saline-alkali-tolerant grasses and shrubs, and large trees are relatively rare.

[0006] At present, the main vegetation restoration methods for the degraded sandy grasslands with saline-alkalization and desertification are as follows: Mechanical sand barriers (such as straw checkerboards, nylon grids, etc.) can fix sand dunes in the short term, with high costs and easy aging. However, in areas where the loose sand layer of the degraded grassland is relatively thin, its applicability is weak and it is used less; Covering technologies such as straw, plastic film, and ecological blankets can reduce wind erosion, but there is a risk of secondary pollution (such as plastic residues), relatively high costs, and certain damage to the scattered vegetation on the grassland during laying; Directly spreading mixed improvement materials or plant seeds wrapped in capsules requires a large amount of improvement materials, with a low vegetation survival rate and uncertain restoration.

[0007] Therefore, the present invention is proposed. Summary of the Invention

[0008] The purpose of the present invention is to provide a vegetation restoration method for saline-alkali desertified degraded grasslands, which can utilize the terrain of the saline-alkali desertified degraded grasslands for micro-transformation, with low costs, high plant survival rate and good vegetation restoration effect.

[0009] The present invention provides a vegetation restoration method for saline-alkali desertified degraded grasslands, including the following steps:

[0010] S1. Before winter comes, dig planting pit units, where each planting pit unit includes a plurality of triangular ditches arranged. The direction of each triangular ditch is perpendicular to the perennial prevailing wind in the area to be restored, and a triangular ridge is formed between two adjacent triangular ditches;

[0011] S2. Lay coir fiber blanket strips inside the triangular ditches and press soil on them;

[0012] S3. In the second spring, mix sand: carbon source: water-retaining agent: potassium fulvate: agricultural waste in a mass ratio of 50:(20 - 30):(5 - 10):(3 - 6):(5 - 8) to obtain a modified material mixture. Spray water to keep the humidity of the modified material mixture at 30% - 40%, and fill the middle of the triangular ditch with the modified material mixture, pressing down the coir fiber blanket strips so that both sides of the coir fiber blanket strips are closely attached to the side of the triangular ditch, and the edges on both sides of the coir fiber blanket strips are exposed to the air;

[0013] S4. Mix shrub seeds and herb seeds, soak and germinate them, and then plant them in the modified material mixture;

[0014] S5. Sprinkle water in the small ditch formed between the modified material mixture and the side of the triangular ditch to soak the coir fiber blanket strips.

[0015] Further, the planting pit units are in an X shape, and the directions of each triangular ditch are the same.

[0016] Further, in step S1, the length of the triangular ditch is 30 - 40 cm and the depth is 25 - 35 cm.

[0017] Further, in step S1, the length of the triangular ridge is the same as that of the triangular ditch, and the ridge height is 10 - 15 cm; the side of the triangular ditch or / and the triangular ridge is quadrilateral, more preferably rhombic.

[0018] Further, in step S2, the width of the coir fiber blanket strip is 20 - 25 cm, and the pore diameter of the coir fiber blanket strip is 2 - 3 cm.

[0019] Further, the carbon source in step S3 is peat soil or biochar.

[0020] Further, the agricultural waste in step S3 is wood chips or bagasse.

[0021] The improved material mixture provided by the present invention uses peat soil or biomass charcoal to increase the organic matter content of the soil. According to the later test data, the average organic matter content of the soil at the roots of plants in the triangular gully has increased by 2.3%-3.1%. The water-retaining agent largely inhibits soil water evaporation, reduces water leakage, and increases the saturated water content of the soil. After absorbing water and becoming saturated, it swells into hydrogel crystals, which can retain part of the heat energy generated by daytime sunlight, regulate the night temperature, reduce the soil temperature difference between day and night, and is conducive to the stable growth of the roots of plants for planting or cutting, making it easier for plants to grow in clusters. In addition to increasing the air permeability of the soil, wood chips or bagasse mainly cooperate with the water-retaining agent to absorb, store and retain more water and fertilizer, making the soil at the roots of vegetation form lumps in a larger area and preventing the roots of vegetation from being exposed by wind erosion. Potassium humate can improve the soil structure, increase the air permeability and water retention of the soil, reduce soil compaction, and promote root development. It can also combine with minerals in the soil to form stable soil colloids, which have the functions of nitrogen fixation, phosphorus dissolution, and potassium activation, and enhance the fertilizer retention capacity of the soil.

[0022] Further, in the step S3, the filling depth of the improved material mixture in the triangular gully is 5-8 cm.

[0023] Further, in the step S4, the mass ratio of shrub seeds to herb seeds is 1:(1-1.5); the shrub seeds are two or more of Haloxylon ammodendron, Atriplex canescens, Hedysarum scoparium, and Hedysarum mongolicum, and the herb seeds are two or more of Agropyron desertorum, Achnatherum splendens, and Suaeda glauca.

[0024] The bottom of the triangular gully provided by the present invention is relatively low-lying, and the soil and water conditions are relatively good, which is suitable for the growth of drought-tolerant, salt-tolerant, and sand-resistant plants such as Haloxylon ammodendron, Atriplex canescens, Hedysarum scoparium, Hedysarum mongolicum, Agropyron desertorum, Achnatherum splendens, and Suaeda glauca. Moreover, the roots of Haloxylon ammodendron, Atriplex canescens, and Achnatherum splendens are developed, which can firmly fix the sandy soil and at the same time adapt to the relatively barren soil environment at the bottom of the triangular gully.

[0025] Further, the specific process of the step S4 is as follows: After mixing the shrub seeds and herb seeds, soak them in warm water for 1-2 days, then evenly sprinkle the soaked seeds in the middle of the improved material mixture, and then bury the seeds with the improved material mixture on both sides in the triangular gully. The planting depth of the seeds is kept at 2-3 cm, and the improved material mixture in the triangular gully forms a triangular bulge and is compacted.

[0026] In summary, the present invention has the following advantages:

[0027] The technical solution of the present invention utilizes the microtopography of the degraded grassland affected by saline desertification for transformation. By connecting the triangular ditches and triangular ridges excavated before winter, it can play the role of wind sheltering, soil accumulation, snow storage, water accumulation and soil moisture conservation. In arid areas with strong winds, reducing the wind speed can effectively reduce soil erosion and reduce the flow of the saline layer enriched on the surface, creating a stable environment for plant growth. The regularly undulating terrain can effectively reduce the flow and accumulation of the saline layer on the soil surface layer, reduce the soil salt content, increase the soil organic matter content, and increase the contents of nitrogen, phosphorus and potassium in the soil. After the terrain shaping is completed, the mixture of improvement materials placed in the triangular ditches can improve the organic matter content, saturated water content, air permeability, water retention capacity and fertilizer retention capacity of the soil. The coconut coir fiber blanket strips set have a natural porous structure and hygroscopicity. At night, the water vapor in the air is easily condensed due to the temperature difference, and can adsorb and retain water, intensifying the soil moisture at the bottom of the triangular ditches. Therefore, the bottom of the triangular ditches set in the present invention is relatively low-lying, and the soil and water conditions are relatively good. By planting drought-tolerant, salt-tolerant and sand-resistant shrub vegetation and grass vegetation that can fix sandy soil, the grassland affected by saline desertification can achieve good restoration effects, and the whole method is simple to operate and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a partial structural schematic diagram of the planting pit unit in the embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of the spatial distribution of the planting pit unit in the embodiment of the present invention;

[0031] Figure 3 It is the effect diagram after vegetation restoration in the embodiment of the present invention;

[0032] Figure 4 It is the effect diagram after vegetation restoration in Comparative Example 1 of the present invention.

[0033] Explanation of the reference numerals: 1 - triangular ditch; 2 - coconut coir fiber blanket strip; 3 - quadrilateral side of the triangular ditch; 4 - vegetation; 5 - mixture of improvement materials; 6 - small ditch; 7 - triangular ridge; 8 - prevailing wind throughout the year. SPECIFIC EMBODIMENTS

[0034] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0036] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined. In addition, the terms "mounted", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] Embodiment

[0038] A method for vegetation restoration of saline-desertified degraded grassland is as follows:

[0039] Taking a certain Bashang grassland area as an example, the northwest wind prevails in this area all year round. According to statistics, the number of days with strong winds above level 6 is 57 - 130 days per year, and the maximum wind speed reaches 38 m / s. There are many saline-alkali and sandy desertified degraded grasslands.

[0040] S1. Dig planting pit units in the shape of an X in October before the arrival of winter, as Figure 2As shown in the figure, this embodiment is provided with 6 triangular grooves 1. One side of the planting pit unit has 4 triangular grooves, and the other side has 2 triangular grooves. A triangular ridge 7 is formed between two adjacent triangular grooves 1. A triangular ridge 7 is also provided on the side of the outermost triangular groove 1. The center position of the planting pit unit is the triangular ridge 7, and all the areas adjacent to the periphery of the triangular ridge 7 at the center position are triangular grooves 1. The orientation of each triangular groove 1 is perpendicular to the prevailing wind 8 in this restored area. The orientation of the triangular groove 1 is southwest-northeast (perpendicular to the northwest wind direction); the triangular groove 1 is 30 cm long and about 25 - 30 cm deep, the triangular ridge 7 is 30 cm long and about 10 - 15 cm high. The sides of both the triangular groove 1 and the triangular ridge 7 are rhomboid, and the four-sided inclined plane of the triangular ridge 7 should be patted and compacted with a shovel.

[0041] S2. Lay coir fiber blanket strips 2 (as shown in the figure) inside the triangular groove 1, with a width of about 25 cm. The coir fiber blanket strips 2 are woven from relatively thick coir fibers and have holes on them, with the hole size being about 2 - 3 cm. Continuously press a small amount of planting soil in the middle of the coir fiber blanket strips 2 to keep both sides of the coir fiber blanket strips 2 closely attached to the side of the triangular groove 1. Figure 1 As shown in the figure.

[0042] S3. At the end of April in the spring of the second year, mix sand: peat soil: water-retaining agent: potassium fulvate: sugarcane bagasse (the sugarcane bagasse needs to be crushed to less than 3 cm) in a mass ratio of 50:30:8:6:8, and spray water to keep its humidity at about 30 - 40%, maintaining a loose state to obtain a modified material mixture; fill the modified material mixture 5 into the middle of the triangular groove 1, with the filling depth kept at about 6 - 8 cm, pressing down the coir fiber blanket strips 2, and ensuring that the fiber filaments on both sides of the coir fiber blanket strips 2 are exposed (exposed to the air).

[0043] S4. Collect seeds of shrubs (Haloxylon ammodendron and Atriplex canescens) and herbs (Achnatherum splendens and Suaeda glauca) and mix them in a mass ratio of 1:1.5. After soaking them in warm water for 1 - 2 days, mix the soaked seeds and fine sand with a humidity of about 40% in a volume ratio of 3:2, and evenly sprinkle them in the middle of the modified material mixture 5. Then bury the seeds with the modified material mixture 5 on both sides in the groove. The planting depth of the seeds is kept at about 3 cm. Finally, the modified material mixture 5 in the triangular groove 1 forms a triangular raised shape and is compacted.

[0044] S5. Sprinkle water in the two small grooves 6 formed between the raised part of the modified material mixture and the side surfaces of both sides of the triangular groove 1 to ensure that the coir fiber blanket strips 2 are thoroughly soaked. The vegetation restoration structure is as shown in the figure. Figure 1 As shown in the figure.

[0045] After 1 - 2 weeks, the grass germinated evenly, and some shrubs germinated. The growth of Achnatherum splendens and Suaeda glauca was good. By July - August, the triangular gully was submerged at the root of the vegetation, and sporadic Haloxylon ammodendron and Atriplex canescens appeared. In April of the third year, healthy Haloxylon ammodendron branches were used for certain cuttage and replanting among the Achnatherum splendens clusters. In July - August, the grass - shrub ratio was good, and the regional vegetation recovered well (as shown in Figure 3 ), with the vegetation coverage rate reaching over 65%. There was no triangular gully without vegetation in the planting area. Soil performance tests were conducted on the soil taken from 10 different triangular gullies, and the test results are shown in Table 1. The average pH value of the triangular gully soil was 8.19, the average organic matter content reached 4.55%, and the water content reached 9.46%. In the fourth year, stable vegetation clusters in the shape of strips gradually formed in multiple triangular gullies. In the larger vegetation clusters, plants such as Allium mongolicum were seen, plant diversity increased, and there were also nests of some small animals. The vegetation coverage in the experimental area was good, presenting a grassland patch landscape.

[0046] Table 1 Soil Performance Test

[0047] Sampling point pH Organic matter content % Water content % 1 7.9 3.5 8.9 2 8.6 3.62 7.5 3 7.6 4.32 9.2 4 8.4 4.55 8.4 5 8.2 4.34 9.2 6 7.6 7.63 8.8 7 8.6 5.34 9.1 8 8.7 3.98 11.9 9 8.2 4.32 12.1 10 8.1 3.9 9.5 Average value 8.19 4.55 9.46

[0048] Comparative Example 1

[0049] A method for vegetation restoration of saline - desertified degraded grassland. The area to be restored selected in this comparative example is the same as that in Example 1, and the technical solution is also basically the same as that in the example. The only difference is that: in step S1 of this Comparative Example 1, the direction of the triangular gully is northwest - southeast (along the northwest wind direction).

[0050] After treating the restoration area with the method of this comparative example, after 1 - 2 weeks, the herbs germinated evenly, some shrubs germinated, and the growth of Achnatherum splendens and Suaeda glauca was good. Subsequently, after 1 - 2 months, some roots of Achnatherum splendens were exposed and died. By July - August, some triangular gullies were submerged at the root of the vegetation, and sporadic Haloxylon ammodendron and Atriplex canescens appeared. In April of the third year, healthy Haloxylon ammodendron branches were used for certain cuttage and replanting among the Achnatherum splendens clusters. In July - August, the grass - shrub ratio was good, and the vegetation in some areas recovered well (as shown in Figure 4 ), with the vegetation coverage rate reaching about 45%, and about 55% of the triangular gullies had no vegetation or sporadic Achnatherum splendens and Suaeda glauca. The average pH value of the soil in the triangular gullies with good vegetation growth (10 sampling points were set) was 8.38, the average organic matter content reached 3.31%, and the water content was 9.43%. The pH values were tested at 5 sampling points in the triangular gullies without vegetation, ranging from 8.5 - 9.7, and the organic matter content was 0.3% - 2% (some of the collected samples contained the improved material mixture).

[0051] Table 2 Soil Performance Test in Comparative Example 1

[0052] Sampling point pH Organic matter content % Water content % 1 8.4 3.3 8.4 2 8.2 3.5 10.2 3 8.6 3.7 11.2 4 7.9 2.3 10.5 5 8.6 4.1 10.2 6 8.7 3.2 8.2 7 7.8 2.8 7.4 8 8.8 3.5 8.9 9 8.5 4.1 9.2 10 8.3 2.6 10.1 Average value 8.38 3.31 9.43

[0053] Comparative Example 2

[0054] A method for vegetation restoration of saline desertified degraded grassland. The area to be restored selected in this comparative example is the same as that in the example. The specific process is as follows:

[0055] S1. Dig conical pits in October before winter comes. The diameter of the conical pits is about 20 - 25 cm, and the depth is about 25 cm. The distance between conical pits is between 3 - 5 cm. The sides of the conical pits are compacted with a spade.

[0056] S2. Lay coir fiber blanket strips around the bottom of the cone at the bottom of the conical pit, with a width of about 25 cm. The coir fiber blanket strips are woven from relatively thick coir fibers and have holes on them, with the hole size of about 2 - 3 cm. Continuously press a small amount of planting soil in the middle of the coir fiber blanket strips, and keep both sides closely attached to the sides of the conical pit.

[0057] S3. At the end of April in the coming spring, mix sand: peat soil: water - retaining agent: potassium fulvate: sugarcane bagasse (crushed to less than 3 cm) in a mass ratio of 50:30:8:6:8, spray water to keep its humidity at about 30 - 40%, and keep it in a loose state to obtain a modified material mixture; fill the modified material mixture into the bottom of the conical pit, with the filling depth kept at about 8 cm, press down the coir fiber blanket strips, and keep the fiber filaments of the coir fiber blanket strips exposed, closely attached to the sides of the conical pit.

[0058] S4. Mix the collected shrub (Haloxylon ammodendron and Atriplex canescens) and herb (Achnatherum splendens and Suaeda glauca) seeds in a mass ratio of 1:1.5, soak them in warm water for 1 - 2 days, then mix the soaked seeds and fine sand with a humidity of about 40% in a volume ratio of 3:2, evenly sprinkle them in the middle of the modified material mixture, and then bury the seeds with the modified material mixture on both sides of the ditch. The depth of the seeds is kept at about 3 cm. Finally, the mixture at the bottom of the conical pit forms a small conical bulge and is compacted.

[0059] S5. Sprinkle water in the circular small ditch formed between the small conical bulge and the side of the conical pit to ensure that the coir fiber blanket strips are thoroughly soaked.

[0060] After 1 - 2 weeks, the herbs germinated evenly, and the shrubs began to germinate. The growth of Achnatherum splendens and Suaeda glauca was relatively good. By July - August, the bottom of the conical pit was already submerged in the roots of the vegetation. The shrubs Haloxylon ammodendron and Atriplex canescens appeared sporadically. In the following July - August, the grass - shrub ratio was relatively good, and the vegetation recovery was relatively good in some areas, with the vegetation coverage rate reaching about 50%. In the planting area, the vegetation coverage on the upper side of the conical pit and between the conical pits was insufficient. There was no vegetation in about 40% - 45% of the area. The average soil pH of the conical pits with good vegetation growth (6 sampling points were set) was 8.13, the average organic matter content reached 4.1%, and the water content was 7.15%. The pH values of 10 sampling points in the triangular gully without vegetation were 8.3 - 10, and the organic matter content was 0.12% - 2.1%. The sand mobility between the conical pits was relatively large, and the plant clusters in the conical pits were relatively small. After the 4th year of restoration, most of the circular - dot - shaped vegetation clusters became smaller compared with the 3rd year, and the trend of degradation was relatively obvious. The predicted long - term sustainability was weak.

[0061] Table 3 Soil performance test in Comparative Example 2

[0062] Sampling point pH Organic matter content % Water content % 1 8.2 3.5 6.2 2 8.1 3.9 8.4 3 7.9 3.2 6.3 4 8.3 4.6 6.7 5 7.8 4.6 8.2 6 8.5 4.8 7.1 Average value 8.13 4.1 7.15

[0063] The present invention utilizes the fact that the microtopography of saline-alkali and desertified degraded grasslands is relatively easy to transform and the cost is relatively low. The triangular ditches and ridges excavated before winter are connected, which can play the role of storing wind, soil and snow, and accumulating water to preserve soil moisture. In arid areas with strong winds, reducing the wind speed can effectively reduce soil erosion and reduce the flow of the saline-alkali layer enriched on the surface, creating a stable environment for plant growth. The X-shaped spatial distribution law of undulating terrain can effectively reduce the flow and accumulation of the saline layer on the soil surface, reduce the soil salt content, increase the soil organic matter content, and increase the contents of nitrogen, phosphorus and potassium in the soil. After the terrain shaping is completed, a mixture of improvement materials is placed at the bottom of the pit. Among them, peat soil and biochar increase the soil organic matter content. According to the later test data, the average organic matter content of the soil at the roots of plants in the triangular ditches increases by 2.3%-3.1%; the water-retaining agent greatly inhibits soil water evaporation, reduces water leakage, and increases the soil saturated water content. After absorbing water and becoming saturated, it expands into hydrogel crystals, which can retain part of the heat energy generated by daytime sunlight, regulate the night temperature, reduce the soil day-night temperature difference, and is conducive to the stable growth of the roots of plants for planting or cutting, making it easy for plants to grow in clusters; in addition to increasing the soil air permeability, wood chips and bagasse mainly cooperate with the water-retaining agent to absorb, store and retain more water and fertilizer, making the soil at the roots of the vegetation form lumps in a larger range and preventing the roots of the vegetation from being exposed by wind erosion; potassium humate can improve the soil structure, increase the soil air permeability and water retention capacity, reduce soil compaction, and promote root development. It can also combine with minerals in the soil to form stable soil colloids, which have the functions of nitrogen fixation, phosphorus dissolution and potassium activation, and enhance the soil fertilizer retention capacity. The coconut coir fiber blanket strips pressed with the improved mixture are easy to condense the water vapor in the air due to the temperature difference at night because of their natural porous structure and hygroscopicity. They can adsorb and retain water, intensifying the soil moisture at the bottom of the triangular ditches. Therefore, the bottom of the triangular ditches is relatively low-lying, and the soil and water conditions are relatively good, suitable for planting drought-tolerant, saline-alkali-tolerant and wind-sand-tolerant plants such as Haloxylon ammodendron, Atriplex canescens, Hedysarum scoparium, Hedysarum mongolicum, Agropyron desertorum, Achnatherum splendens, Suaeda glauca, etc. The roots of Haloxylon ammodendron, Atriplex canescens, Achnatherum splendens, etc. are developed and can firmly fix the sandy soil, and at the same time can also adapt to the relatively barren soil environment at the bottom of the pit.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for vegetation restoration of saline-desertified degraded grassland, characterized in that, It includes the following steps: S1. Before winter comes, dig planting pit units, where each planting pit unit includes a plurality of triangular ditches arranged. The orientation of each triangular ditch is perpendicular to the perennial prevailing wind in the area to be restored, and a triangular ridge is formed between two adjacent triangular ditches; S2. Lay coconut coir fiber blanket strips inside the triangular ditches and press soil on them; S3. In the spring of the second year, mix sand: carbon source: water-retaining agent: potassium fulvate: agricultural waste in a mass ratio of 50:(20 - 30):(5 - 10):(3 - 6):(5 - 8) to obtain a modified material mixture. Spray water to keep the humidity of the modified material mixture at 30% - 40%, and fill the middle of the triangular ditch with the modified material mixture, pressing down the coconut coir fiber blanket strips so that both sides of the coconut coir fiber blanket strips are closely attached to the sides of the triangular ditch, and the edges on both sides of the coconut coir fiber blanket strips are exposed to the air; S4. Mix shrub seeds and herb seeds, soak and germinate them, and then plant them in the modified material mixture; S5. Sprinkle water in the small ditch formed between the modified material mixture and the side of the triangular ditch to soak the coconut coir fiber blanket strips thoroughly.

2. The vegetation restoration method according to claim 1, characterized in that The planting pit units are in an X shape, and the orientation of each triangular ditch is the same.

3. The vegetation restoration method according to claim 1, characterized in that, In step S1, the length of the triangular ditch is 30 - 40 cm and the depth is 25 - 35 cm.

4. The vegetation restoration method according to claim 3, characterized in that, In step S1, the length of the triangular ridge is the same as that of the triangular ditch, and the ridge height is 10 - 15 cm; the side of the triangular ditch or / and the triangular ridge is quadrilateral.

5. The vegetation restoration method according to claim 1, characterized in that, In step S2, the width of the coconut coir fiber blanket strip is 20 - 25 cm, and the pore size of the coconut coir fiber blanket strip is 2 - 3 cm.

6. The vegetation restoration method according to claim 1, characterized in that, The carbon source in step S3 is peat soil or biochar.

7. The vegetation restoration method according to claim 1, characterized in that, The agricultural waste in step S3 is wood chips or bagasse.

8. The vegetation restoration method according to claim 1, characterized in that, In step S3, the filling depth of the modified material mixture in the triangular ditch is 5 - 8 cm.

9. The vegetation restoration method according to claim 1, wherein In step S4, the mass ratio of shrub seeds to herb seeds is 1:(1 - 1.5); the shrub seeds are two or more of Haloxylon ammodendron, Atriplex canescens, Hedysarum scoparium, Hedysarum mongolicum, and the herb seeds are two or more of Agropyron desertorum, Achnatherum splendens, Suaeda glauca.

10. The vegetation restoration method according to claim 1, wherein The specific process of step S4 is as follows: After mixing shrub seeds and herb seeds, soak them in warm water for 1 - 2 days, then evenly sprinkle the germinated seeds in the middle of the modified material mixture, and then bury the seeds with the modified material mixture on both sides in the triangular ditch. The planting depth of the seeds is kept at 2 - 3 cm, and the modified material mixture in the triangular ditch forms a triangular bulge and is compacted.

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