An ecological afforestation method for abandoned mining areas

Abstract

The present invention provides an ecological afforestation method for abandoned mining areas, belonging to the technical field of heavy metal contaminated soil treatment. The ecological afforestation method of the present invention includes afforesting on the abandoned mining area according to the configuration ratio of 4 cypress trees + 1 catalpa tree. Through the afforestation mode configuration and transformation of the technical scheme of the present invention, the soil fertility of the abandoned mining area is increased by 10%, the soil enzyme activity is increased by 15%, the soil and water conservation ability is increased by 12%, and the total amount of heavy metals in the soil of the abandoned mining area is reduced by 10%, and the afforestation and restoration effect is very remarkable.

Description

Technical Field

[0001] The present invention belongs to the technical field of heavy metal contaminated soil treatment, and particularly relates to an ecological afforestation method for abandoned mine areas. Background Art

[0002] An abandoned mine area refers to land that has been damaged due to mining activities and cannot be used without treatment.

[0003] Regarding restoration or treatment methods, those currently mainly involved are tailings utilization, soil remediation, vegetation restoration, and microbial remediation. Among them, people can use the method of artificially planting vegetation to improve and restore the ecological system of abandoned mine areas. Abandoned mine areas are one of the main heavy metal pollution sources. Reducing soil and water loss and blocking the migration and diffusion of heavy metals through phytoremediation are effective pollution source control approaches. However, in practical applications, vegetation restoration usually faces the problem of difficult vegetation restoration caused by poor physical and chemical properties of the soil and heavy metal stress. Therefore, systematic research and development of ecological afforestation and phytoremediation technologies for difficult-to-establish sites contaminated by heavy metals in mining areas have important theoretical and practical values. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an ecological afforestation method for abandoned mine areas, which uses selected heavy metal-resistant and drought-tolerant tree species for pattern configuration to improve the soil of abandoned mine areas and reduce the heavy metal content.

[0005] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] An ecological afforestation method for abandoned mine areas, in which afforestation is carried out in the abandoned mine area according to the configuration ratio of 4 cypress trees + 1 catalpa tree.

[0007] Preferably, the abandoned mine area is an abandoned antimony mine area.

[0008] Preferably, before afforestation, the forest land is cleared to remove miscellaneous shrubs, weeds, and vine plants that affect afforestation and the growth of forest trees on the afforestation land.

[0009] Preferably, land preparation is carried out in November - December before afforestation, fish-scale pits are dug to plant tree seedlings, and the planting density is 80 - 100 plants per mu.

[0010] More preferably, the specifications of the fish-scale pits are 45 - 55 cm × 45 - 55 cm × 35 - 45 cm.

[0011] More preferably, the tree seedlings are container seedlings or bare-root seedlings over 2 years old.

[0012] More preferably, the container seedlings are planted after rain in April - May, and the bare-root seedlings are planted after rain in February - March.

[0013] More preferably, during the planting, first backfill a part of the topsoil, apply organic fertilizer, then backfill another part of the topsoil and mix well. After transplanting the saplings, apply a water-retaining agent, cover the soil and compact the root ball, and cover with a weed-proof cloth.

[0014] More preferably, the application rate of the organic fertilizer is 2 - 3 kg per hole, and the application rate of the water-retaining agent is 40 - 100 g per hole.

[0015] Preferably, after afforestation, tending management is carried out, including topdressing in the second and third years after planting; checking the forest land in the first three years after planting for replanting; and removing weeds around the saplings.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention provides an ecological afforestation method for mining wasteland. Through the afforestation mode configuration and afforestation method of the technical solution of the present invention, the soil fertility of the mining wasteland is increased by 10%, the soil enzyme activity is increased by 15%, the soil and water conservation ability is increased by 12%, and the total amount of heavy metals in the soil of the mining wasteland is reduced by 10%. The afforestation and restoration effect is very remarkable. Description of the Drawings

[0018] Figure 1 : Flow chart of the ecological afforestation method for mining wasteland; In the figure: A Site preparation and digging fish-scale pits, B Backfill topsoil and organic fertilizer, C Plant saplings and apply water-retaining agent, D Cover with weed-proof cloth;

[0019] Figure 2 : Comparison of the growth differences of Chinese fir in Chinese fir forests with different mixed ratios;

[0020] Figure 3 : Characteristics of heavy metal content in the soil of Chinese fir forests with different mixed ratios;

[0021] Figure 4 : Characteristics of soil nutrients in Chinese fir forests with different mixed ratios;

[0022] Figure 5 : Characteristics of soil enzyme activity in Chinese fir forests with different mixed ratios. Detailed Embodiments

[0023] The present invention provides an ecological afforestation method for mining wasteland, and carries out afforestation in the mining wasteland according to the configuration ratio of 4 Chinese fir trees + 1 Catalpa ovata tree; preferably, the mining wasteland is the waste land of an antimony mining area.

[0024] The present invention preferably conducts forest land cleaning before afforestation to remove miscellaneous shrubs, weeds, and vine plants that affect afforestation and the growth of forest trees on the afforestation land; further preferably, the cleared materials can be covered around young trees or newly planted young trees to keep the young trees warm, retain water, and inhibit weed growth; more preferably, burning of the mountain is not allowed during the forest land cleaning process to maximize the protection of the original vegetation in the antimony mining area and ensure that the afforestation work will not have an adverse impact on the growth of the original vegetation. The present invention preferably conducts forest land cleaning in October to November.

[0025] The present invention preferably conducts land preparation before afforestation from November to December, dig fish-scale pits to plant tree seedlings, and the planting density is 80 - 100 plants / mu. Further preferably, the planting density is 90 plants / mu, and the row spacing is 2.5m × 3m. The fish-scale pits have a certain water storage depth and can store more water, which has the effect of preventing soil erosion. The present invention further preferably has the fish-scale pit specifications of 45 - 55cm × 45 - 55cm × 35 - 45cm, and more preferably 50cm × 50cm × 40cm. As an implementable way, when digging fish-scale pits, stones, tree roots, branches, weeds and other sundries should be picked out.

[0026] The present invention preferably uses container seedlings or bare-root seedlings over two years old for tree planting; further preferably, container seedlings are planted after rain in April to May, and bare-root seedlings are planted after rain in February to March. As an implementable way, if the weather is dry, artificial irrigation is carried out.

[0027] When the present invention preferably plants trees, first backfill a part of the topsoil, apply organic fertilizer and then backfill another part of the topsoil and mix well. After transplanting the tree seedlings, apply water-retaining agent, cover the soil and compact the root ball, and cover with a weed-proof cloth. Covering the weed-proof cloth can not only prevent the growth of weeds, but also keep moisture and preserve soil moisture, reserve growth space and a certain light area for the newly planted plants to improve the survival rate of afforestation and promote the growth of forest trees. Further preferably, the diameter or width of the weed-proof cloth is 1 - 1.5m, and the periphery is compacted with stones or covered with soil.

[0028] The present invention preferably applies 2 - 3kg / hole of organic fertilizer, further preferably 2.5kg / hole, and more preferably the organic fertilizer is well-rotted chicken manure with an organic matter content ≥ 40% and an effective viable bacteria count ≥ 0.2 billion / g. The preferred application rate of the water-retaining agent is 40 - 100g / hole, and further preferably 70g / hole. The present invention does not limit the specific sources of the organic fertilizer and the water-retaining agent, and they can be directly obtained through commercial channels. As an implementable way, the model of the water-retaining agent in the present invention is "Agricultural Fertilizer (2015) Temporary License No. 9067".

[0029] The present invention preferably conducts tending management after afforestation, including:

[0030] Top-dressing is carried out in the second and third years after planting; further preferably, 0.2 - 0.3kg / plant of compound fertilizer is top-dressed once a year, and the nutrient content of the compound fertilizer N:P2O5:K2O ≥ 45%; more preferably, the top-dressing time is from May to June;

[0031] Check the forest land three years before planting and carry out replanting; it is further preferably to check 1 - 2 times a year, especially after heavy rain, carefully check whether there is scouring damage;

[0032] Remove the weeds around the saplings; it is further preferably to remove the weeds and shrubs within a range of 1 m centered on the plant. Generally, there is no grass growth within a range of 1 - 1.5 m around the plant because of the weed control cloth, and only the weeds and shrubs within a range of 0.5 m around the weed control cloth need to be removed; more preferably, the tending time is in June and September every year.

[0033] The present invention also includes the prevention and control of diseases and pests in the forest land; highlighting the concept of mainly preventing and controlling by ecological afforestation measures, once it occurs, adhere to the scientific prevention and control mainly by biological and physical methods and supplemented by chemical methods.

[0034] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they cannot be understood as limiting the protection scope of the present invention. Embodiment

[0035] An ecological afforestation method for abandoned mining areas includes the following steps:

[0036] (1) Forest land cleaning: From October to November, remove the shrubs, weeds, and vine plants that affect afforestation and the growth of forest trees on the afforestation land;

[0037] (2) Land preparation: From November to December, dig fish-scale pits with a specification of 50 cm × 50 cm × 40 cm, the hole spacing of the fish-scale pits is 2.5 m × 3 m, 1 hole for 1 plant, ensuring a planting density of 90 plants per mu; when digging the holes, pick out sundries such as stones, tree roots, tree branches, and weeds;

[0038] (3) Planting:

[0039] Determine that the tree species are Chinese cypress and Catalpa ovata, 2-year-old container seedlings or bare-root seedlings, and carry out planting and afforestation according to the configuration of 4 Chinese cypress trees + 1 Catalpa ovata tree; the container seedlings are planted after rain in April - May, and the bare-root seedlings are planted after rain in February - March;

[0040] When planting, first backfill a part of the topsoil in the fish-scale pit, apply 2.5 kg of organic fertilizer and mix well. The organic fertilizer is well-rotted chicken manure, with an organic matter content ≥ 40% and an effective viable bacteria count ≥ 0.2 billion / g. Then backfill another part of the topsoil and mix well. After planting the seedlings, evenly sprinkle a circle of water-retaining agent of 70 g around the seedlings, cover the soil and compact the root ball. After planting, cover a weed control cloth with a diameter of 1 m around the seedlings, and compact the periphery with stones or cover the soil;

[0041] (4) Tending management:

[0042] In the second and third years after planting, top-dress the seedlings once a year, applying 0.25 kg of compound fertilizer per plant. The compound fertilizer has N:P2O5:K2O ≥ 45%. The top-dressing time is from May to June.

[0043] In the second year after planting, in June or September, with the seedling as the center, remove the weeds and shrubs within a range of 1 m.

[0044] In the first three years after planting, conduct 1 - 2 inspections every year. For plots with serious soil erosion, immediately take replanting measures. The replanting method and time are the same as in step (3).

[0045] (5) Pest and disease control: Highlight the concept of mainly using ecological afforestation measures for prevention and control. Once they occur, adhere to scientific control with biological and physical control as the main methods and chemical control as the auxiliary method. Example

[0046] An ecological afforestation method for abandoned mining areas includes the following steps:

[0047] (1) Forest land cleaning: From October to November, remove the shrubs, weeds, and vine plants on the afforestation land that affect afforestation and the growth of forest trees.

[0048] (2) Land preparation: From November to December, dig fish-scale pits with a specification of 45 cm × 45 cm × 35 cm. The spacing between fish-scale pits is about 2.5 m × 2.5 m, with 1 hole for 1 plant, ensuring a planting density of 100 plants per mu. When digging the holes, pick out sundries such as stones, tree roots, branches, and weeds.

[0049] (3) Planting:

[0050] Determine the tree species as Chinese fir and Catalpa ovata. Use 2-year-old container seedlings or bare-root seedlings for planting and afforestation according to the configuration of 4 Chinese fir trees + 1 Catalpa ovata tree. Container seedlings are planted after rain from April to May, and bare-root seedlings are planted after rain from February to March.

[0051] When planting, first backfill a part of the topsoil in the fish-scale pit, apply 2 kg of organic fertilizer and mix well. The organic fertilizer is decomposed chicken manure, with an organic matter content ≥ 40% and an effective viable bacteria count ≥ 0.2 billion / g. Then backfill another part of the topsoil and mix well. After planting the seedlings, evenly sprinkle a circle of 40 g of water-retaining agent around the seedlings, cover the soil and mound it up and compact. After planting, cover a weed-proof cloth with a diameter of 1 m around the seedlings, and compact it with stones or cover the soil on the periphery.

[0052] (4) Cultivation and management:

[0053] In the second and third years after planting, top-dress the seedlings once a year, applying 0.3 kg of compound fertilizer per plant. The compound fertilizer has N:P2O5:K2O ≥ 45%. The top-dressing time is from May to June.

[0054] In the second year after planting, in June or September, taking the seedlings as the center, remove the weeds and shrubs within a range of 1.5 m;

[0055] In the first three years after planting, conduct 1 - 2 inspections every year. For the plots with serious soil erosion, immediately take replanting measures. The replanting method and time are the same as in step (3);

[0056] (5) Pest and disease control: Highlight the concept of mainly using ecological afforestation measures for prevention and control. Once pests and diseases occur, adhere to scientific control with biological and physical control as the main methods and chemical control as the auxiliary method. Example

[0057] An ecological afforestation method for abandoned mining areas includes the following steps:

[0058] (1) Forest land cleaning: In October - November, remove the shrubs, weeds, and vine plants on the afforestation land that affect afforestation and tree growth;

[0059] (2) Land preparation: In November - December, dig fish - scale pits with a specification of 55 cm × 55 cm × 45 cm. The spacing between fish - scale pits is about 3 m × 3 m, with 1 hole for 1 plant, ensuring a planting density of 80 plants per mu; When digging the holes, pick out stones, tree roots, tree branches, weeds and other sundries;

[0060] (3) Planting:

[0061] Determine the tree species as Chinese fir and Catalpa ovata. Use 2 - year - old container seedlings or bare - root seedlings for planting and afforestation according to the configuration of 4 Chinese firs + 1 Catalpa ovata; Container seedlings are planted after rain in April - May, and bare - root seedlings are planted after rain in February - March;

[0062] When planting, first backfill a part of the topsoil in the fish - scale pit, apply 3 kg of organic fertilizer and mix well. The organic fertilizer is decomposed chicken manure, with an organic matter content ≥ 40% and an effective viable bacteria count ≥ 0.2 billion / g. Then backfill another part of the topsoil and mix well. After planting the seedlings, evenly spread a circle of 100 g of water - retaining agent around the seedlings, cover the soil and compact the root ball. After planting, cover a weed - proof cloth with a diameter of 1.5 m around the seedlings and compact it with stones or cover the soil at the periphery;

[0063] (4) Tending management:

[0064] In the second and third years after planting, top - dress the seedlings once a year, with 0.2 kg of compound fertilizer per plant. The compound fertilizer N:P2O5:K2O ≥ 45%. The top - dressing time is in May - June;

[0065] In the second year after planting, in June or September, taking the seedlings as the center, remove the weeds and shrubs within a range of 1.5 m;

[0066] In the first three years after planting, conduct 1 - 2 inspections every year. For the plots with serious soil erosion, immediately take replanting measures. The replanting method and time are the same as in step (3);

[0067] (5)Pest and disease control: Highlight the concept of taking ecological forestation measures as the main prevention and control method. Once pests and diseases occur, adhere to the scientific prevention and control method that mainly uses biological and physical control and supplemented by chemical control. Examples

[0068] Five mixed forest patterns of 9-year-old cypress trees were established in the abandoned land of Qixing Second Group in the Lengshuijiang Antimony Mine Area, Hunan Province. They are: for every 10 mixed vegetation plants, there are 2 cypress trees + 5 catalpa bungei trees + 3 privet trees (B2Q5L3), 6 cypress trees + 4 holly trees (B6D4), 7 cypress trees + 3 choerospondias axillaris trees (B7N3), 8 cypress trees + 2 catalpa ovata trees (B8Z2), and a pure cypress forest of 10 trees (B10). The pure cypress forest (B10) was used as a control.

[0069] For each pattern, 3 plots of 20m×30m were set up respectively. Each cypress tree in the plots was measured for its diameter at breast height, and its diameter at breast height and tree height were investigated. For each tree species in each plot, 3 average trees were sampled to collect root, branch, and leaf plant samples for testing the heavy metal contents such as arsenic, cadmium, antimony, and lead. Along the diagonal of each plot, 3 soil profiles were dug in sequence, and 500g of mixed soil samples at a depth of 0-20cm were taken from each soil profile and put into sealed bags and taken back to the laboratory for measuring soil heavy metals, soil nutrients, and soil enzyme activity indicators.

[0070] (1)Comparison of the growth differences of cypress trees in cypress forests with different mixing ratios

[0071] Figure 2 -A The results show that the order of the average diameter at breast height of cypress trees in different patterns is: B8Z2>B7N3>B6D4>B2Q5L3>B10. The average diameter at breast height of cypress trees in the B8Z2 pattern is the largest, which is 2.88cm; the B10 pattern is the smallest, which is 1.37cm; the B7N3, B6D4, and B2Q5L3 patterns are medium, which are 2.35, 2.27, and 1.40cm respectively; except for the B2Q5L3 pattern, there are significant differences in the average diameter at breast height between the pure cypress forest and the other 3 mixed forest patterns. There is no significant difference in the average diameter at breast height of cypress trees between the B7N3 and B6D4 patterns, but the B8Z2 pattern is significantly higher than the other patterns.

[0072] Figure 2The results of -B show that the average tree heights of Chinese fir in different patterns are ranked as follows: B7N3 > B8Z2 > B6D4 > B2Q5L3 > B10. The average tree height of Chinese fir in the B7N3 pattern is the largest, reaching 3.11 m; the B10 pattern is the smallest, with an average tree height of 2.04 cm; the B8Z2, B6D4, and B2Q5L3 patterns are at a medium level, being 3.00, 2.85, and 2.50 m respectively. There are significant differences in the average tree heights between the pure Chinese fir forest and the other four mixed patterns. Among the B7N3, B6D4, and B8Z2 patterns, there is a significant difference in the average tree height of Chinese fir only between B7N3 and B6D4, but these three patterns are all significantly higher than the other patterns.

[0073] (2)Comparison of heavy metal contents in the soil of Chinese fir forests with different mixed ratios

[0074] Figure 3 The results show that except for Pb, there are significant differences in the contents of Sb, As, and Cd in the soil of the pure Chinese fir forest B10 and the other four mixed pattern forestlands. Among them, the ranking of the soil Sb contents in each pattern is: B8Z2 > B6D4 > B7N3 > B10 > B2Q5L3, and there are significant differences between each pattern. The largest is the B8Z2 pattern, with an Sb content reaching 597.33 mg / kg, and the smallest is the B2Q5L3 pattern with 121.00 mg / kg ( Figure 3 -A); the ranking of the soil As contents in each pattern is: B10 > B6D4 > B8Z2 > B7N3 > B2Q5L3. There is no significant difference between the B6D4 pattern and B10, but these two patterns are significantly different from the other three patterns ( Figure 3 -B); the ranking of the soil Cd contents in each pattern is: B2Q5L3 > B10 > B6D4 > B8Z2 > B7N3. There is no significant difference only between B8Z2 and B7N3 in pairwise comparison, and there are significant differences between other patterns ( Figure 3 -D); there are significant differences in the Pb contents of the B7N3 pattern compared with B2Q5L3, B6D4, and B8Z2, while there is no significant difference between the pure Chinese fir forest pattern B10 and other patterns ( Figure 3 -C).

[0075] Overall, according to the Nemerow pollution index evaluation standard, the soil in the study area has extremely strong Sb, As, and Cd pollution and mild Pb pollution. Among them, the highest contents of Sb, As, Cd, and Sb reach 543.03, 20.95, 10.11, and 1.49 times the local (Hunan) soil background values respectively.

[0076] (3)Comparison of soil nutrients in Chinese fir forests with different mixed ratios

[0077] Figure 4The results showed that there were significant differences in the available nitrogen, available phosphorus, available potassium, and organic matter content between the pure cypress forest B10 and the other four mixed forest patterns. Among them, there were significant differences in soil available phosphorus between each pattern ( Figure 4 -B); there were significant differences in organic matter between the B10 pattern and the other patterns, but there were no significant differences among the other four patterns ( Figure 4 -D); there were significant differences in available nitrogen between the B10 pattern and the other patterns, but among the other patterns, B7N3 was significantly greater than the other three mixed forest patterns ( Figure 4 -A); there were significant differences in available potassium between the B10 pattern and the other patterns. Among the other patterns, there were no significant differences only between B6D4 and B8Z2, and there were significant differences among the other patterns ( Figure 4 -C). Generally speaking, the available nitrogen, available phosphorus, available potassium, and organic matter content of the pure cypress forest pattern B10 were significantly lower than those of the other four cypress mixed forest patterns, indicating that the mixed forest had a better effect on soil improvement and restoration in the mining area than the pure forest pattern.

[0078] (4) Analysis of soil enzymes in cypress forests with different mixing ratios

[0079] Figure 5 The results showed that there were significant differences in the soil catalase activities among the five patterns, and their order of magnitude was: B2Q5L3 > B8Z2 > B6D4 > B7N3 > B10. Among them, the B2Q5L3 pattern was the highest, reaching 5.89 mg / g, and the B10 pattern was the lowest, only 1.61 mg / g. The catalase activities of the B8Z2, B6D4, and B7N3 patterns were 5.21, 4.64, and 2.76 mg / g respectively ( Figure 5 -A); the order of magnitude of the soil sucrase activities of the five patterns was: B6D4 > B7N3 > B2Q5L3 > B10 > B8Z2, and the corresponding soil sucrase activities were 9.23, 7.33, 6.67, 6.29, and 5.13 mg / g respectively. There were significant differences only between the pure cypress forest B10 pattern and the B6D4 pattern, and there were no significant differences with the other patterns. Moreover, there were significant differences between the B6D4 pattern and the other mixed forest patterns ( Figure 5 -B); the order of magnitude of the soil urease activities of the five patterns was: B8Z2 > B6D4 > B7N3 > B2Q5L3 > B10, and the corresponding soil urease activities were 0.061, 0.048, 0.038, 0.032, and 0.030 mg / g respectively. There were no significant differences only between the pure cypress forest B10 pattern and the B2Q5L3 pattern, and there were significant differences with the other patterns. Moreover, there were significant differences among the other three patterns ( Figure 5-C); The order of the soil phosphatase activities in the five patterns is: B2Q5L3 > B6D4 > B8Z2 > B7N3 > B10, and the corresponding soil phosphatase activities are 15.13, 12.77, 12.27, 8.30, and 6.94 mg / 100 g respectively. There was no significant difference in the B10 pattern of the pure cypress forest only between the B7N3 pattern, and there were significant differences with other patterns, and the other three patterns were significantly greater than the B10 and B7N3 patterns ( Figure 5 -D).

[0080] (5)Comprehensive evaluation of the forest land soil of cypress forests with different mixing ratios

[0081] Based on the principal component analysis of the forest land soil quality of each mixed pattern with 12 indicators of soil heavy metals, soil available nutrients and soil enzymes, the factor analysis results obtained four principal components (Table 1). Among them, the variance contribution rate of principal component 1 was 45.369%, the variance contribution rate of principal component 2 was 24.347%, the variance contribution rate of principal component 3 was 14.301%, the variance contribution rate of principal component 4 was 10.543%, and the cumulative variance contribution rate reached 94.560%. This indicates that these 4 principal components retained most of the information of the evaluation indicators of the mixed forest land soil quality. Therefore, these 4 principal components were selected as the basis for the comprehensive evaluation of the forest land soil quality. Principal component 1 accounted for the largest proportion, and the weight coefficients of available nitrogen, available phosphorus, organic matter, and catalase content were relatively large, all exceeding 0.800, indicating that principal component 1 mainly reflected the forest land soil quality indicators such as available nitrogen, available phosphorus, organic matter, and catalase; while principal component 2 mainly reflected heavy metal indicators such as antimony and cadmium content, and principal components 3 and 4 mainly reflected indicators such as lead, arsenic, and invertase.

[0082] Arsenic, lead, cadmium, available nitrogen, available phosphorus, available potassium, organic matter, catalase, invertase, urease, phosphatase. Substitute the relevant indicators of each tree species pattern into the score function, calculate the principal component scores of each pattern, and perform weighted summation according to the corresponding contribution rates to obtain the comprehensive scores of the soil quality of each pattern (Table 2).

[0083] Table 1 Principal component factor matrix of forest land soil quality

[0084]

[0085] Table 2 Scores of forest land soil quality in different mixed patterns

[0086]

[0087] As can be seen from Table 2, the soil quality of the forest land with the mixed planting pattern of 8 cypress trees + 2 catalpa trees is the highest, with a comprehensive score of 87.276. Followed by the mixed planting pattern of 6 cypress trees + 4 holly trees, with a score value of 69.855. The patterns of 7 cypress trees + 3 choerospondias axillaris and 2 cypress trees + 5 catalpa bungei + 3 privet trees rank third and fourth respectively, with score values of 47.225 and 29.707. The pure cypress forest pattern of 10 cypress trees ranks last, with a comprehensive score of 28.797. The overall ranking of the soil quality scores of each pattern is: B8Z2 > B6D4 > B7N3 > B2Q5L3 > B10. Generally speaking, the soil quality of several cypress and broad-leaved tree mixed forests is better than that of the pure cypress forest, and the mixed planting pattern of 8 cypress trees + 2 catalpa trees is the best.

[0088] The above description is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An ecological afforestation method for abandoned mining areas, characterized in that, Afforestation is carried out on the abandoned mining area according to the configuration ratio of 4 cypress trees + 1 catalpa tree; the abandoned mining area is an abandoned antimony mining area; the planting density of the afforestation is 80 - 100 plants per mu.

2. The ecological afforestation method for abandoned mining areas according to claim 1, characterized in that, Land preparation is carried out in November - December before the afforestation, and fish-scale pits are dug to plant saplings.

3. The ecological afforestation method for abandoned mining areas according to claim 2, wherein, The specifications of the fish-scale pits are 45 - 55 cm × 45 - 55 cm × 35 - 45 cm.

4. The ecological afforestation method for abandoned mining areas according to claim 2, characterized in that, The saplings are container seedlings or bare-root seedlings over 2 years old.

5. The ecological afforestation method for abandoned mining areas according to claim 4, characterized in that, The container seedlings are planted after rain in April - May, and the bare-root seedlings are planted after rain in February - March.

6. The ecological afforestation method for abandoned mining areas according to claim 2, characterized in that, During the planting, first backfill a part of the topsoil, apply organic fertilizer and then backfill another part of the topsoil and mix well. After transplanting the saplings, apply water-retaining agent, cover the soil and compact the root ball, and cover with weed-proof cloth.

7. The ecological afforestation method for the abandoned land in the mining area according to claim 6, wherein, The application rate of the organic fertilizer is 2 - 3 kg per hole, and the application rate of the water-retaining agent is 40 - 100 g per hole.

8. The ecological afforestation method for abandoned mining areas according to claim 1, characterized in that, After afforestation, tending management is carried out, including topdressing in the second and third years after planting; checking the forest land in the first three years after planting and carrying out replanting; removing weeds around the saplings.

9. The ecological afforestation method for abandoned mining areas according to claim 1, characterized in that Before the afforestation, the forest land is cleared to remove miscellaneous shrubs, weeds and vine plants that affect afforestation and the growth of forest trees on the afforestation land.

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