Method for soil improvement and vegetation recovery of abandoned white sandstone in open pit coal mine in northern high and cold grassland mining area

Abstract

The invention belongs to the technical field of ecological restoration, and particularly relates to a soil improvement and vegetation restoration method for abandoned white sandstone in open pit coal mines in northern alpine grassland mining areas. The invention provides a northern high and cold steppe mining area open pit coal mine waste white sandstone soil improvement and vegetation recovery method. The method comprises the following steps: (1) performing field management and waste white sandstone soil fertilization and rejuvenation for one year before sowing; (2) in the second year, applying fertilizer, then performing rotary tillage once at the depth of 14-16 cm, and watering thoroughly; then carrying out secondary rotary tillage with the depth of 6-8cm, and sowing the seed composition; the seed composition comprises oat, awnless brome, festuca rubra, elytrigia intermedium, new wheat straw, puccinellia divaricata and Russian medicago sativa; and (3) performing maintenance management after sowing.

Description

Technical Field

[0001] The invention belongs to the technical field of ecological restoration, and in particular relates to a method for improving abandoned white sandstone soil in open-pit coal mines in northern alpine grassland mining areas and restoring vegetation. Background Art

[0002] Coal plays an important role in my country's national economy. However, with the rapid development of my country's economy and the increasing demand for coal resources, the continuous expansion of mineral resource mining has had a considerable negative impact on the ecology and environment of grassland areas. For example, the quality and yield of grassland forage have declined, the biodiversity of plant communities has been lost, the groundwater level has dropped, the soil and vegetation structure has changed, and soil erosion and sandstorms have occurred frequently, leading to the deterioration of grassland ecology and seriously affecting the normal functioning of grassland ecosystem services. The mining of coal resources is a complex and long-term project. With the destruction of grassland ecological environment by mining, the geological environment has also been severely damaged, which is easy to cause pollution of soil, air, water and other bodies in the surrounding areas, which will not only cause ecological imbalance, but also bring harm to the workers and surrounding residents in the mining area. Therefore, soil and water conservation work and ecological restoration in the mining area are particularly important.

[0003] In order to build an important ecological security barrier in northern my country and reduce the pollution of atmospheric dust, water bodies, soil and other ecological environments, it is a top priority to realize the ecological environment protection and utilization of the northern alpine grassland mining areas, and to do a good job in ecological restoration of the northern alpine grassland mining areas and restore the agricultural and animal husbandry production capacity of the mining areas.

[0004] Therefore, the ecological restoration of abandoned white sandstone dumps in open-pit coal mines in northern alpine grassland mining areas has received increasing attention. Summary of the invention

[0005] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0006] In recent years, my country has launched green mines, mine parks, land reclamation and other projects in the ecological management of mining areas in the northern alpine grasslands. The implementation of these projects has greatly promoted the improvement of the ecological environment of the grasslands in the mining areas and the improvement of the quality of life of the people in the mining areas, and the vegetation and biodiversity have also been restored. However, in the ecological restoration and vegetation restoration of open-pit coal mine dumps in the northern alpine grassland mining areas, there are some shortcomings, especially in the coldest Hulunbuir area in my country, where the extreme cold temperature is minus 36℃ or even lower. Plant varieties that perform well, safely overwinter, and have excellent production performance in most parts of the country cannot survive the severe winter here, and either freeze to death in winter or die in large numbers during the late spring cold. In addition, due to the tight use of land resources and insufficient funds, many areas of the spoil dump are not covered with soil, and ecological management is carried out directly. The types of managed varieties are few, the varieties are single, the cold resistance is poor, and most of them are purchased from outside. The pure yellow mudstone and white sandstone soil spoil dump areas with poor soil conditions are basically barren. For example, in the open-pit coal mine in Yiminhe Town, Ewenki Autonomous Banner, Hulunbuir City, Inner Mongolia, more than 20 plant varieties were planted for ecological restoration of the mine spoil dump. In the second year, only 5 to 6 varieties turned green again, and they continued to degenerate and decrease. In the third year, only about 3 varieties were left, forming large areas of bald spots, which needed to be reseeded.

[0007] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, an embodiment of the present invention proposes a method for improving the soil and restoring vegetation of abandoned white sandstone in open-pit coal mines in northern alpine grassland mining areas. The method selects drought-resistant, cold-resistant, and salt-alkali-resistant plants for planting to improve the soil and restore vegetation. Through scientific and reasonable on-site investigation, statistics, analysis, and measurement, the best modifier, fertilization, plant planting combination, and maintenance method are obtained to improve the soil of the loose white sandstone dump with strong alkaline soil to form a soil aggregate structure, which is conducive to the survival and growth of most cold-resistant plants.

[0008] The method for improving soil and restoring vegetation in abandoned white sandstone of open-pit coal mines in northern alpine grassland mining areas according to the embodiment of the present invention comprises the following steps:

[0009] (1) Field management and fertilization of abandoned white sandstone soil for one year before sowing;

[0010] (2) In the second year, the soil is tilled once after applying fertilizer to a depth of 14 to 16 cm and watered thoroughly; then, the soil is tilled a second time to a depth of 6 to 8 cm and a seed composition is sown; the seed composition includes oats, awnless brome, red fescue, intermediate wheatgrass, new wheatgrass, alkali grass and Russian miscellaneous clover;

[0011] (3) Carry out maintenance management after sowing.

[0012] The advantages and technical effects brought by the method for improving and restoring vegetation of abandoned white sandstone soil in open-pit coal mines in northern alpine grassland mining areas according to the embodiment of the present invention are as follows: 1. The method of the embodiment of the present invention uses oats that grow rapidly, have strong stress resistance, and have economic value. The ecological restoration effect can appear in the same year and can provide a basis for ecological restoration in the early stage; the selected awnless brome, intermediate wheatgrass, alkali grass, etc. are suitable for establishing communities on poor, strongly alkaline, loose white sandstone soils, and at the same time, the associated new wheatgrass and miscellaneous alfalfa with excellent tolerance and resistance are selected to grow well in the community; 2. The method of the embodiment of the present invention uses plant species that can adapt to the harsh natural environment and soil conditions of coal mines in northern alpine grassland mining areas and the abandoned white sandstone soil in open-pit coal mines in alpine grassland areas, and can overcome the extremely harsh conditions of vegetation restoration, soil and water conservation, and living environment in strongly alkaline, loose white sandstone soils. In terms of ecological restoration and soil improvement, the community establishment and the associated plant varieties have been tested. The data accumulated by experience are scientifically and reasonably matched, and perennial plants with excellent qualities such as drought resistance, cold resistance, salt-alkali resistance, and strong stress resistance, and which can safely overwinter under extreme conditions of minus 36°C and below, are selected. Considering the perfect combination of artificial planting and natural growth, a near-native, natural and long-lasting vegetation ecological restoration community is finally created to give full play to the advantages of plants; 3. The method of the embodiment of the present invention takes into account plant species, community structure and economic value, and selects plant varieties with strong overwintering ability, salt-alkali resistance, drought resistance, strong adaptability and superior stress resistance, which can ensure the emergence rate, survival rate and overwintering rate, and achieve ideal restoration effects; 4. The method of the embodiment of the present invention applies high-efficiency water-soluble chelated humic acid fertilizer while sowing the seed combination, which can improve the strongly alkaline white sandstone soil and supplement the nutrients required for plant growth, so that the vegetation grows strong and the root system is well developed, so as to achieve the purpose of deep improvement of the white sandstone soil.

[0013] In some embodiments, in the step (1), the field management and fertilization and rejuvenation of abandoned white sandstone soil for one year includes: watering once in early May to dilute the salt and alkali of the white sandstone; in mid-May, applying 3.6-3.8 t / mu of farmer's decomposed cattle and sheep manure, 35-45 kg / mu of organic fertilizer, 28-34 kg / mu of mineral potassium humate, and 20-26 kg / mu of granular microbial fertilizer with trace elements, and rotary tilling once after fertilization to a depth of 18-20 cm, and then watering thoroughly and maintaining the land for one year.

[0014] In some embodiments, the organic matter content in the organic fertilizer is greater than 52wt%; the mineral source potassium humate contains fulvic acid ≥52wt%, humic acid ≥34wt%, and organic matter ≥12wt%; the medium and trace element bacterial fertilizer granules contain boron, zinc, manganese, sulfur, magnesium, molybdenum, copper, iron, calcium, silicon and selenium, and the number of effective live bacteria is ≥1 billion / g.

[0015] In some embodiments, in step (2), the volume ratio of oats, awnless brome, red fescue, thinlyleaved elytris, new wheatgrass, alkaligrass and Russian miscellaneous alfalfa in the seed composition is 1:0.6~1.0:0.4~0.8:0.6~1.0:0.4~0.8:0.4~0.8:0.2~0.6.

[0016] In some embodiments, in step (2), the volume ratio of oats, awnless brome, red fescue, thinlyleaved elytris, new wheatgrass, alkaligrass and Russian miscellaneous alfalfa in the seed composition is 1:0.8:0.6:0.8:0.6:0.6:0.4.

[0017] In some embodiments, in step (2), the sowing rate of the seed composition is 18-22 g / m 2 The sowing time is from mid-May to mid-August, and the sowing depth is 1cm to 3cm.

[0018] In some embodiments, in step (2), the fertilizers applied include: 0.8-1.2 t / mu of farm-composted cattle and sheep manure, 28-32 kg / mu of organic fertilizer, 22-27 kg / mu of mineral potassium humate, and 16-20 kg / mu of medium and trace element bacterial fertilizer granules.

[0019] In some embodiments, the pH of the white sandstone soil is 9-11.

[0020] In some embodiments, in step (3), the maintenance management includes:

[0021] (a) Water after sowing and cover with straw mats;

[0022] (b) Monitor the surface humidity and temperature within half a month after sowing, and control the surface humidity at 65-75% RH and the surface temperature at 18-28°C;

[0023] (c) After the seedlings emerge and reach the tillering stage, apply 20-26 kg / mu of organic fertilizer, 12-16 kg / mu of mineral potassium humate and 8-12 kg / mu of microbial fertilizer granules with trace elements, and water until they are dissolved;

[0024] (d) In the third year, water the seedlings in early May. When the seedlings reach the jointing stage, apply 20-26 kg / mu of organic fertilizer, 12-16 kg / mu of potassium humate from mineral sources, and 8-12 kg / mu of micro-element fertilizer granules. Water until all the fertilizers are dissolved. When the plants reach the transition period between vegetative growth and reproductive growth, apply 18-22 kg / mu of organic fertilizer, 8-12 kg / mu of potassium humate from mineral sources, and 6-12 kg / mu of micro-element fertilizer granules. Water until all the fertilizers are dissolved.

[0025] (e) In the fourth year, water the plants in early May and apply top dressing fertilizer at the same time and in the same way as in the third year.

[0026] In some embodiments, the maintenance management further includes: watering with antifreeze water around mid-October after sowing in the first year. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below. The embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0028] The method for improving soil and restoring vegetation in abandoned white sandstone of open-pit coal mines in northern alpine grassland mining areas according to the embodiment of the present invention comprises the following steps:

[0029] (1) Field management and fertilization of abandoned white sandstone soil for one year before sowing;

[0030] (2) In the second year, the soil is tilled once after applying fertilizer to a depth of 14 to 16 cm and watered thoroughly; then, the soil is tilled a second time to a depth of 6 to 8 cm and a seed composition is sown; the seed composition includes oats, awnless brome, red fescue, intermediate wheatgrass, new wheatgrass, alkali grass and Russian miscellaneous clover;

[0031] (3) Carry out maintenance management after sowing.

[0032] The method for improving and restoring vegetation in abandoned white sandstone soil of open-pit coal mines in northern alpine grassland mining areas according to the embodiment of the present invention uses oats that grow rapidly, have strong stress resistance, and have economic value, can produce ecological restoration effects in the same year, and can provide a basis for ecological restoration in the early stage; the selected awnless brome, intermediate wheatgrass, alkali grass, etc. are suitable for establishing communities on poor, strongly alkaline, loose white sandstone soils, and at the same time, associated new wheatgrass and mixed flower alfalfa with excellent tolerance and resistance qualities are selected to grow well in the community; the method according to the embodiment of the present invention selects plant species that can adapt to the harsh natural environment and soil conditions of coal mines in northern alpine grassland mining areas and the white sandstone soil of waste gas from open-pit coal mines in alpine grassland areas, can overcome the extremely harsh conditions of vegetation restoration, soil and water conservation, and living environment in strongly alkaline, loose white sandstone soils, and in ecological restoration and soil improvement, the establishment of communities and associated plant varieties are scientifically and reasonably combined through experimentally accumulated data. The method of the embodiment of the present invention comprehensively considers aspects such as plant species, community structure and economic value, and selects plant varieties with strong overwintering ability, salt-alkali tolerance, drought resistance, strong adaptability and excellent stress resistance, which can ensure the emergence rate, survival rate and overwintering rate, and achieve ideal restoration effect; the method of the embodiment of the present invention applies high-efficiency water-soluble chelated humic acid fertilizer while sowing the seed combination, which can improve the strongly alkaline white sandstone soil and supplement the nutrients required for plant growth, so that the vegetation grows strong and the root system is well developed, thereby achieving the purpose of deep improvement of the white sandstone soil.

[0033] In some embodiments, preferably, in the step (1), the field management and fertilization and rejuvenation of abandoned white sandstone soil for one year includes: watering thoroughly before sowing in early May to dilute the salinity and alkali of the white sandstone; in mid-May, applying 3.6-3.8 t / mu of farmer's decomposed cattle and sheep manure, 35-45 kg / mu of organic fertilizer, 28-34 kg / mu of mineral potassium humate, and 20-26 kg / mu of granular microbial fertilizer with trace elements, rotary tilling once after fertilization to a depth of 18-20 cm, and cultivating the land for one year after watering thoroughly.

[0034] In some embodiments, preferably, the organic matter content in the organic fertilizer is greater than 52wt%; the mineral source potassium humate contains fulvic acid ≥52wt%, humic acid ≥34wt%, and organic matter ≥12wt%; the medium and trace element bacterial fertilizer granules contain boron, zinc, manganese, sulfur, magnesium, molybdenum, copper, iron, calcium, silicon and selenium, and the number of effective live bacteria is ≥1 billion / g.

[0035] In some embodiments, preferably, in step (2), the volume ratio of oats, awnless brome, red fescue, thin wheatgrass, new wheatgrass, alkaligrass and Russian miscellaneous lucerne in the seed composition is 1: 0.6-1.0: 0.4-0.8: 0.6-1.0: 0.4-0.8: 0.4-0.8: 0.2-0.6. Further preferably, the volume ratio of oats, awnless brome, red fescue, thin wheatgrass, new wheatgrass, alkaligrass and Russian miscellaneous lucerne in the seed composition is 1: 0.8: 0.6: 0.8: 0.6: 0.6: 0.4.

[0036] In the embodiment of the present invention, the proportion of each variety in the seed composition is based on the botanical characteristics of the variety, and the proportion of the variety in the native vegetation community of the northern alpine natural grassland and the size of the seed and the plant varieties with similar functions are planted in combination. The seed composition is most suitable for soil improvement and vegetation restoration of abandoned white sandstone in open-pit coal mines in northern alpine grassland mining areas.

[0037] In some embodiments, preferably, in step (2), the sowing amount of the seed composition is 18-22 g / m 2 The sowing time is from mid-May to mid-August, and the sowing depth is 1cm to 3cm. The appropriate sowing amount can achieve the effect of fine sowing, with low cost investment, and no need to cover the soil and apply farmyard manure under irrigation conditions.

[0038] In some embodiments, preferably, in step (2), the fertilizers applied include: 0.8-1.2 t / mu of farm-rotted cattle and sheep manure, 28-32 kg / mu of organic fertilizer, 22-27 kg / mu of mineral potassium humate and 16-20 kg / mu of medium and trace element bacterial fertilizer granules.

[0039] The composition of the fertilizer applied in the embodiment of the present invention is designed based on the test and analysis results of the soil and moisture in the white sandstone soil dumping ground with poor soil conditions in the open-pit coal mine in the alpine grassland area. It is adapted to local conditions, more suitable for the growth of vegetation in the area, and conducive to the restoration of the ecosystem.

[0040] In some embodiments, the pH of the white sandstone soil is 9 to 11. White sandstone soil is the abandoned soil of open-pit coal mines in the northern alpine grassland mining area. It is a strongly alkaline loose soil with a particularly poor ability to retain moisture and fertilizer. It contains a large amount of toxic and harmful substances and cannot be used for agricultural and animal husbandry production. Vegetation cannot grow and it is dry and rainless.

[0041] In some embodiments, preferably, in step (3), the maintenance management includes:

[0042] (a) Watering after sowing and covering with straw mats to ensure the surface temperature and moisture conditions are suitable for plant germination and growth, and to avoid soil erosion and seed exposure;

[0043] (b) Monitor the surface humidity and temperature within half a month after sowing, control the surface humidity at 65-75% RH, and the surface temperature at 18-28°C, and water in time to increase moisture and reduce temperature to avoid the phenomenon of bud drying and seedling death during seed germination and seedling growth;

[0044] (c) After the seedlings emerge and reach the tillering stage, apply 20-26 kg / mu of organic fertilizer, 12-16 kg / mu of mineral potassium humate, and 8-12 kg / mu of medium and trace element fertilizer granules, and water until they are dissolved;

[0045] (d) In the third year, water the seedlings in early May. When the seedlings reach the jointing stage, apply 20-26 kg / mu of organic fertilizer, 12-16 kg / mu of mineral potassium humate and 8-12 kg / mu of medium and trace element fertilizer granules. Water until all the fertilizers are dissolved. When the plants reach the transition period between vegetative growth and reproductive growth, apply 18-22 kg / mu of organic fertilizer, 8-12 kg / mu of mineral potassium humate and 6-10 kg / mu of medium and trace element fertilizer granules. Water until all the fertilizers are dissolved. This ensures that the plants complete flowering and fruiting and a complete growth period.

[0046] (e) In the fourth year, water the plants in early May and apply topdressing fertilizer at the same time and in the same manner as in the third year. This can effectively degrade the dead branches and leaves of the vegetation and convert them into humus on the ground surface, greatly increasing the organic matter content of the white sandstone soil. After that, maintenance measures will be taken after monitoring factors such as climate conditions, vegetation growth, plant diversity and yield to avoid ineffective cost investment and waste of materials.

[0047] In some embodiments, preferably, the maintenance management further comprises: watering with antifreeze water around mid-October after sowing in the first year. The open-pit coal mine in the alpine grassland area is located in the high-latitude cold area of ​​my country, and the winter comes early. Watering with antifreeze water around mid-October, the antifreeze water must be poured thoroughly.

[0048] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0049] Example 1

[0050] (1) Select abandoned white sandstone soil with flat ground, little rain, strong alkaline and loose pH value of 9.5 for ecological restoration and soil improvement. First, carry out field management and fertilization of abandoned white sandstone soil for one year: in mid-May 2021, apply 3.6-3.8t / mu of decomposed cattle and sheep manure, 40kg / mu of organic fertilizer (organic matter content > 52%), 32kg / mu of mineral potassium fulvic acid (fulvic acid ≥ 52%, humic acid ≥ 34%, organic matter ≥ 12%), and 24kg / mu of medium and trace element bacterial fertilizer granules (containing boron, zinc, manganese, sulfur, magnesium, molybdenum, copper, iron, calcium, silicon and selenium, and effective live bacteria count ≥ 1 billion / g). After fertilization, rotary tillage once to a depth of 18-20cm, and water thoroughly to dissolve;

[0051] (2) In mid-May 2022, apply 0.8-1.2 t / mu of decomposed cattle and sheep manure, 30 kg / mu of organic fertilizer, 25 kg / mu of mineral potassium humate and 18 kg / mu of medium and trace element fertilizer granules. After fertilization, till the soil once to a depth of 14-16 cm and water thoroughly. In early June, perform a second tillage to a depth of 6-8 cm and sow a seed composition, wherein the seed composition comprises oats, awnless brome, red fescue, intermediate wheatgrass, new wheatgrass, alkali grass and Russian miscellaneous alfalfa in a volume ratio of 1:0.8:0.6:0.8:0.6:0.6:0.4;

[0052] (3) Water after sowing and cover with straw mats to ensure the surface temperature and moisture conditions are suitable for plant germination and growth, and to avoid soil erosion and seed exposure;

[0053] (4) Within half a month after sowing, the surface humidity and temperature need to be carefully monitored to ensure that the surface humidity is controlled at 70% RH and the surface temperature is controlled at 20°C. Watering should be done in a timely manner to increase moisture and reduce temperature to avoid the phenomenon of bud drying and seedling death during seed germination and seedling growth;

[0054] (5) After germination, during the branching (tillering) period, apply 24kg / mu of organic fertilizer, 14kg / mu of mineral potassium humate, and 10kg / mu of medium and trace element fertilizer granules, and water to dissolve them completely to relieve and reduce the alkali of white sandstone;

[0055] (6) Water with antifreeze water around mid-October, and make sure the water is thoroughly poured;

[0056] (7) In 2023, water the plants in early May. When the seedlings reach the branching (jointing) stage, apply 24kg / mu of organic fertilizer, 14kg / mu of mineral potassium humate, and 10kg / mu of medium and trace element fertilizer granules. Water until all the fertilizers are dissolved. When the plants reach the transition period between vegetative growth and reproductive growth, apply 20kg / mu of organic fertilizer, 10kg / mu of mineral potassium humate, and 8kg / mu of medium and trace element fertilizer granules. Water until all the fertilizers are dissolved. This ensures that the plants complete flowering and fruiting and a complete growth period.

[0057] (8) After watering in early May 2024, the time and method of topdressing shall be the same as in the third year. After that, maintenance measures shall be taken after monitoring factors such as climate conditions, vegetation growth, plant diversity and yield.

[0058] The growth data of the plant varieties in this embodiment were statistically analyzed, and the results are shown in Table 1; the soil was tested and analyzed, and the results are shown in Table 2.

[0059] Table 1. Soil improvement and vegetation restoration of abandoned white sandstone in open-pit coal mines in northern alpine grassland mining areas. Combined planting methods. Planting area. Ecological restoration variety growth data

[0060]

[0061]

[0062] Table 2 Soil test table for improvement and vegetation restoration of abandoned white sandstone soil in open-pit coal mines in northern alpine grassland mining areas

[0063]

[0064] From the data in Table 1, it can be seen that the seed combination for soil improvement and vegetation restoration in abandoned white sandstone soil of open-pit coal mines in the northern alpine grassland mining area has achieved the effect of soil improvement and vegetation restoration after being planted on the alkaline and loose abandoned white sandstone soil of open-pit coal mines in the alpine grassland mining area. In 2024, the average height of the grass group of soil improvement and vegetation restoration varieties is 61cm, the deepest root depth in the soil reaches 158cm, and the branch (tiller) growth ability is well developed, with an average of 59 branches per plant, especially the number of branches of the leguminous Russian flower alfalfa reaches 224 per plant, and the number of plants is 186 plants / m 2 , coverage 88 / m 2 %, and the wintering rate eventually reached 100%.

[0065] From the data in Table 2, we can know that before the improvement of the abandoned white sandstone soil in the open-pit coal mine in the northern alpine grassland mining area, the soil test analysis in 2021 showed that the abandoned white sandstone soil was strongly alkaline, with extremely low organic matter level 6, extremely low effective phosphorus level 6, extremely low available potassium content level 6, and extremely low hydrolyzable nitrogen content level 6. The conductivity exceeds the normal soil conductivity by 0.05-0.7ms / cm, and the value is too large, which proves that if this type of soil accumulates salt substances for a long time, the evaporation rate of soil water will be too fast, which will eventually lead to low soil fertility, greatly affecting the absorption of nutrients and water by plants in the soil, forming soil conditions where most plants cannot grow normally, resulting in the general high content of nitrates, sulfates and chloride ions that cause salt and alkali damage to the soil, so that a large amount of toxic and harmful substances are formed inside the abandoned white sandstone soil, making it impossible for plants to survive. After 4 years of planting and scientific maintenance, soil testing and analysis in 2024 showed that the soil was neutral, with high organic matter content of level 1, extremely high effective phosphorus of level 1, high available potassium content of level 1, and high hydrolyzable nitrogen content of level 1. The salinizing and alkali-causing toxic and harmful substances in the soil were effectively reduced through the restoration of vegetation, using the adsorption, absorption, transportation, enrichment, and decomposition functions of plants in coordination with the mechanical action of the soil. There is no nitrate in the soil, and the sulfate and chloride ion content is extremely low. The conductivity is within the normal soil conductivity range of 0.05-0.7ms / cm, proving that this type of soil now has a good ability to retain moisture and fertilizer. Normal agricultural and animal husbandry production can be carried out, effectively improving the productivity of abandoned white sandstone soil.

[0066] The method of the present invention was used to carry out ecological restoration and soil improvement of the white sandstone dumping ground of the open-pit coal mine in the northern alpine grassland mining area, and then scientifically and effectively monitored and maintained for the fourth year. The alkalinity of the white sandstone was effectively improved, and the white sandstone soil was changed from white-gray to yellow, gray-black and black, and the effective soil structure micro-aggregates were also formed. The fallen leaves of the vegetation community formed a 1-3 cm humus layer on the surface. More than 86 species of native vegetation were restored, with a coverage of more than 96%, and an average of 268 plants / m 2 After planting on the abandoned white sandstone soil with poor soil conditions in the open-pit mines in the alpine grassland area, except for oats, all crops can safely overwinter in the later period, and their overwintering ability is good. The dry weight of forage yield is about 280kg / mu, the hay can be about 240kg / mu, and the seed yield is about 10kg / mu. Thus, the abandoned strong alkaline loose white sandstone soil with poor soil conditions in the open-pit coal mines in the alpine grassland mining area is turned into treasure, and the utilization rate of white sandstone soil, agricultural and animal husbandry production capacity and ecological function are restored.

[0067] Comparative Example 1

[0068] The restoration method of this comparative example is the same as that of Example 1, except that: in step (2), a traditional seed composition is used for sowing, and the ratio (volume ratio) of traditional seeds: Elymus dahliae: Ice grass: Alfalfa: weed seeds = 1:0.8:0.6:1. In order to increase the emergence rate, survival rate and overwintering rate of the white sandstone soil in the abandoned open-pit coal mine and the vegetation restoration in the northern alpine grassland mining area, the soil is covered with 15-18 cm, and the sowing amount is increased to 84-90 g / m 2 , increase the application of compound fertilizer by 36-42kg / mu, and increase the application of farmyard manure by 3.8-4.2t / mu.

[0069] Table 3 Planting growth data of traditional seed combination planted in improved white sandstone soil

[0070]

[0071]

[0072] From the data of the traditional seed combination planting method in Table 3, it can be concluded that the traditional seed combination planting plant varieties have weak wintering ability. The construction speed of vegetation community in the harsh environment of abandoned white sandstone soil in the open-pit mine in the alpine grassland area is relatively slow, the vegetation is sparse, and a large area of ​​bald spots is formed in the spring of the second year. It requires a large area of ​​soil covering, reseeding and fertilization, which is costly and wastes seeds seriously. Moreover, the community formed in the later period is unstable and the variety is single, which is easily destroyed, and the effect of vegetation restoration is not achieved.

[0073] Comparative Example 2

[0074] The repair method of this comparative example is the same as that of Example 1, except that: in step (2), a modern seed composition is used for sowing, and the seed ratio (volume ratio) of the modern seed composition is 1:0.7:0.6:0.6:0.4:0.4:0.6:0.5:0.8:0.5:0.1:0.6:0.6:1, in order to increase the emergence rate, survival rate and overwintering rate of the white sandstone soil abandoned by open-pit coal mines in the northern alpine grassland mining area and vegetation restoration, the grass varieties and flower varieties that are very suitable for northern ecological greening are used, thereby increasing their ornamental value. Cover the soil with 8-10 cm, and increase the sowing amount to 72-76 g / m 2 , increase the application of mixed compound fertilizer by 26-30kg / mu, and increase the application of farmyard manure by 3-3.6t / mu.

[0075] Table 4 Modern seed combination planting method improved white sandstone soil planting growth data

[0076]

[0077]

[0078]

[0079] From the vegetation growth data of modern seed compositions planted in white sandstone soil in Table 4, it can be concluded that the overwintering ability of plant varieties planted with modern seed compositions is average. The vegetation community built on the abandoned white sandstone soil with poor soil conditions in the Yimin open-pit mine in the alpine grassland area is simple and unstable. As the planting and growth time increases, the species cannot adapt to the soil conditions, nutritional status, irrigation and other reasons of the white sandstone, resulting in the inability of plants to complete the complete life cycle and to bear fruit. The varieties that can safely overwinter in the northern alpine areas also tend to die out and degenerate year by year. Moreover, sporadic bald spots are formed. In the spring of the second year, the bald spots of white sandstone increase in size, and it is necessary to reseed and fertilize, which is a cycle. The cost investment and seed waste will increase year by year. If a long spring drought or late spring cold occurs on the abandoned white sandstone soil, the entire community will be in danger.

[0080] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0081] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas, characterized in that: The following steps are involved: (1) Field management and fertilization of abandoned white sandstone soil for one year before sowing; (2) In the second year, the soil is tilled once after applying fertilizer to a depth of 14 to 16 cm and watered thoroughly; then, the soil is tilled a second time to a depth of 6 to 8 cm and a seed composition is sown; the seed composition includes oats, awnless brome, red fescue, intermediate wheatgrass, new wheatgrass, alkali grass and Russian miscellaneous clover; (3) Carry out maintenance management after sowing.

2. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 1, characterized in that: In the step (1), the field management and fertilization and rejuvenation of the abandoned white sandstone soil for one year include: watering once in early May to dilute the salt and alkali of the white sandstone; in mid-May, applying 3.6-3.8 t / mu of farmer's decomposed cattle and sheep manure, 35-45 kg / mu of organic fertilizer, 28-34 kg / mu of mineral potassium humate and 20-26 kg / mu of medium and trace element fertilizer granules, and rotary tilling once after fertilization to a depth of 18-20 cm, and then watering thoroughly to maintain the land for one year.

3. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 2, characterized in that: The organic matter content in the organic fertilizer is greater than 52wt%; the mineral source potassium humate contains fulvic acid ≥52wt%, humic acid ≥34wt%, and organic matter ≥12wt%; the medium and trace element bacterial fertilizer granules contain boron, zinc, manganese, sulfur, magnesium, molybdenum, copper, iron, calcium, silicon and selenium, and the number of effective live bacteria is ≥1 billion / g.

4. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 1, characterized in that: In the step (2), the volume ratio of oats, awnless brome, red fescue, thinlyleaved elytris, new wheatgrass, alkaligrass and Russian miscellaneous alfalfa in the seed composition is 1:0.6-1.0:0.4-0.8:0.6-1.0:0.4-0.8:0.4-0.8:0.2-0.

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5. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 4, characterized in that: In the step (2), the volume ratio of oats, awnless brome, red fescue, thinlyleaved elytris, new wheatgrass, alkaligrass and Russian miscellaneous lucerne in the seed composition is 1:0.8:0.6:0.8:0.6:0.6:0.

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6. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 1, characterized in that: In the step (2), the sowing amount of the seed composition is 18-22 g / m 2 The sowing time is from mid-May to mid-August, and the sowing depth is 1cm to 3cm.

7. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 1 or 6, characterized in that: In the step (2), the fertilizers applied include: 0.8-1.2 t / mu of farm-composted cattle and sheep manure, 28-32 kg / mu of organic fertilizer, 22-27 kg / mu of mineral potassium humate, and 16-20 kg / mu of medium and trace element bacterial fertilizer granules.

8. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 1, characterized in that: The pH value of the white sandstone soil is 9-11.

9. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 1, characterized in that: In the step (3), the maintenance management includes: (a) Water after sowing and cover with straw mats; (b) Monitor the surface humidity and temperature within half a month after sowing, and control the surface humidity at 65-75% RH and the surface temperature at 18-28°C; (c) After the seedlings emerge and reach the tillering stage, apply 20-26 kg / mu of organic fertilizer, 12-16 kg / mu of mineral potassium humate and 8-12 kg / mu of microbial fertilizer granules with trace elements, and water until they are dissolved; (d) In the third year, water the seedlings in early May. When the seedlings reach the jointing stage, apply 20-26 kg / mu of organic fertilizer, 12-16 kg / mu of potassium humate from mineral sources, and 8-12 kg / mu of micro-element fertilizer granules. Water until all the fertilizer is dissolved. When the plants reach the transition period between vegetative growth and reproductive growth, apply 18-22 kg / mu of organic fertilizer, 8-12 kg / mu of potassium humate from mineral sources, and 6-10 kg / mu of micro-element fertilizer granules. Water until all the fertilizer is dissolved. (e) In the fourth year, water the plants in early May and apply top dressing fertilizer at the same time and in the same way as in the third year.

10. The method for improving soil and restoring vegetation in abandoned white sandstone from open-pit coal mines in northern alpine grassland mining areas according to claim 9, characterized in that: The maintenance management also includes: watering with antifreeze water around mid-October after sowing in the first year.

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