Water and soil conservation and ecological restoration method of high and steep, abandoned slag piles at high elevation with large temperature difference in dry, hot valley

Abstract

A water and soil conservation and ecological restoration method of high and steep, abandoned slag piles at high elevation with large temperature differential in xerothermic drought valleys, comprises: preparing a mixed material; collecting and cutting a plant to obtain a plant ingredient; preparing a treated material; digging tree holes; planting; spreading the treated material, and watering. The water and soil conservation method adds gelling material for cover soil, and stirs to allow fine particles in the cover soil to be uniformly coated on the coarse particles to realize coherence, thus effectively avoiding water erosion and wind erosion on the loose cover soil on a slope and slag pile, reducing the cover soil falling into gaps of large slag pieces on the slope surface, thus controlling the water and cover soil conservation of a slag pile, and the scale of fill earth, and ensuring the survival rate and preservation rate of planted trees.

Claims

1. A water and soil conservation and ecological restoration method, comprising: preparing a uniformly mixed material by taking a soil on a construction site as a cover soil, uniformly mixing a cement with water, and then adding the cover soil into the cement according to a weight ratio of cement to cover soil at 3:100, and stirring, thereby acquiring the uniformly mixed material; collecting and cutting a plant to obtain a plant ingredient by collecting a fresh, non-dry plant, and then cutting the plant into sections of 5-10 cm in length, thereby acquiring the plant ingredient; preparing a treated material by mixing the plant ingredient, the uniformly mixed material and a grass seed, and uniformly stirring, thereby acquiring the treated material, wherein the weight ratio of the grass seed to the cover soil is 3:100 and the weight ratio of the plant ingredient to the cover soil is 4:100; digging tree holes by digging a number of vertical deep holes as the tree holes at 3 m*3 m intervals on a slope, wherein the diameters of the tree holes are 60 cm-80 cm and the depth is 60 cm; covering a cement mortar layer at a bottom of the tree holes, wherein the cement mortar layer has a thickness of 4-6 mm; and lastly covering a clay mud layer on a side wall of each tree hole, wherein the clay mud layer has a thickness of 3-5 mm and a slot is arranged on a place where the clay mud layer is at altitude away from the bottom of each tree hole; planting trees in the tree holes and then backfilling the cover soil; uniformly spreading the treated material in a thickness of 10 cm on the slope on which the trees are planted, and then manually flattening the treated material; and watering the slope covered with the treated material.

2. The water and soil conservation and ecological restoration method according to claim 1, wherein said plants comprise grass clippings.

3. The water and soil conservation and ecological restoration method according to claim 1, wherein said plants comprise straw.

4. The water and soil conservation and ecological restoration method according to claim 1, wherein said plants include grass clippings and straw in a weight ratio of grass clippings to straws of 1:1, and the grass clippings and the straw are cut together and are uniformly mixed.

5. The water and soil conservation and ecological restoration method according to claim 1, wherein spreading the treated material comprises: arranging a number of rows of barriers on the slope, wherein said barriers are inserted at a depth of 40-60 cm into the slope along a direction vertical to the slope, and the barriers have a length of 60-80 cm; and spreading the treated material on the slope after the barriers are completely arranged.

6. The water and soil conservation and ecological restoration method according to claim 5, wherein each of the barriers comprises a branch, and the method further comprises allowing the branches to rot and form organic fertilizer when the trees come into leaf.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is the flow chart of a method provided by the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(2) In order to make the purpose, technical scheme and advantages of the invention be more clear and explicit, the invention is further described in details by combining the figures with the embodiments as below. It should be understood that the described embodiments here are only used for explaining the invention but not for limiting the invention.

(3) A slag disposal pit which is used for stacking the abandoned slag while tunneling and is located on the drought river valley on the upper reaches of the Minjiang River is taken as an experimental area, wherein this area is located in the western Sichuan highland climate area, features a monsoon climate in mountainous regions; in winter, this area is cold and dry, and features strong sunlight, sunny weather, few rainfall and large daily temperature difference; in summer, this area is hot and wet, and features obvious rainy season and has such disasters as strong wind, summer drought, and the like; the average annual rainfall for many years is respectively 507.4 mm; the average temperature for many years is at 13.5 C.; the extreme maximum temperature is at 35.6 C.; the extreme minimum temperature is at 7.4 C.; the maximum rainfall in one day is 66.7 mm; the average annual evaporation capacity for many years is about 1,600 mm. The slags in the slag disposal pit of the experimental area mainly comprise the tunneling digging rock blocks; the geological rocks mostly are sericite phyllite, sandstone, crystalline limestone, and the like; the gradient of the slag disposal pit of the experimental area is at 35-57 degrees.

(4) Firstly, six experimental plots in same areas are divided side by side along the horizontal direction on the slope of the slag disposal pit of the experimental area, and the experimental plots are numbered one by one, wherein the horizontal length of each experimental plot is 15 m, the length along the slope is 60 m and the distance between the two adjacent experimental plots is 1 m.

Embodiment 1: Successively Executing the Following Steps in No. 1 Experimental Plot

(5) A. Uniformly mixing cement with water, adding cover soil collected from the construction site according to a weight ratio of the cement to the cover soil at 3:100, and uniformly stirring, thereby acquiring mixed material;

(6) B. Collecting fresh and non-dry plants, and then cutting the plants into sections in length of 5-10 cm, thereby acquiring plant ingredients;

(7) C. Mixing the plant ingredients acquired from step B, the mixed materials acquired from step A and grass seeds, and uniformly stirring, thereby acquiring treated material, wherein the weight ratio of the grass seeds to the cover soil is 3:100 and the weight ratio of the plant ingredients to the cover soil is: 4:100;

(8) D. Digging vertical deep holes as the tree holes at 3 m*3 m intervals on the slope, wherein the diameters of the tree holes are 60 cm-80 cm and the depth is 60 cm; covering a cement mortar layer at the bottom of the tree holes, wherein the cement mortar layer is in a thickness of 4-6 mm and at a mixture ratio of 1:0.7; and lastly covering a clay mud layer on a side wall of each tree hole, wherein the clay mud layer is in a thickness of 3-5 mm and at a mixture ratio of 1:0.5; and an annular slot is arranged on a place where the clay mud layer is at altitude away from the bottom of each tree hole;

(9) E. Planting trees in the tree holes acquired from step D and then backfilling soil;

(10) F. Uniformly spreading the treated material acquired from step C in a thickness of 10 cm on the slope on which the trees are planted according to step E, and then manually flattening;

(11) G. Watering the slope covered with the treated material.

(12) On the 30th day after step G is finished, starting to measure the moisture content of the soil at 10 cm below the soil surface of the No. 1 experimental plot for the first time, recording, and then repeating the measurement once per 30 days and recording (see Table 1 for the recorded data); in the 12th month after step G is finished, measuring the content of organic matter and nitrogen in the soil on the soil surface of the No. 1 experimental plot, recording, and then repeating the measurement once per 12 months and recording (see Table 2 for the recorded data).

Embodiment 2: Successively Executing the Following Steps in No. 2 Experimental Plot

(13) A. Uniformly mixing clay with water, adding cover soil collected from the construction site according to a weight ratio of the clay to the cover soil at 5:100, and uniformly stirring, thereby acquiring mixed material;

(14) Executing the following steps identical to steps B, C, D, E, F and G in Embodiment 1.

(15) On the 30th day after step G is finished, starting to measure the moisture content of the soil at 10 cm below the soil surface of No. 1 experimental plot for the first time, recording, and then repeating the measurement once per 30 days and recording (see Table 1 for the recorded data); in the 12th month after step G is finished, measuring the content of organic matter and nitrogen in the soil on the soil surface of No. 2 experimental plot, recording, and then repeating the measurement once per 12 months and recording (see Table 2 for the recorded data).

Embodiment 3: Successively Executing the Following Steps in No. 3 Experimental Plot

(16) A. Uniformly mixing coal ash with water, adding cover soil collected from the construction site according to a weight ratio of the coal ash to the cover soil at 3:100, and uniformly stirring, thereby acquiring mixed material;

(17) Executing the following steps identical to steps B, C, D, E, F and G in Embodiment 1.

(18) On the 30th day after step G is finished, starting to measure the moisture content of the soil at 10 cm below the soil surface of No. 3 experimental plot for the first time, recording, and then repeating the measurement once per 30 days and recording (see Table 1 for the recorded data); in the 12th month after step G is finished, measuring the content of organic matter and nitrogen in the soil on the soil surface of No. 3 experimental plot, recording, and then repeating the measurement once per 12 months and recording (see Table 2 for the recorded data).

Contrasting Embodiment 1: Successively Executing the Following Steps in No. 4 Experimental Plot

(19) A. Collecting fresh and non-dry plants, and then cutting the plants into sections in length of 5-10 cm, thereby acquiring plant ingredients;

(20) B. Taking the soil on the construction site as cover soil, mixing the cover soil, grass seeds, the plant ingredients acquired from step A and water, and uniformly stirring, thereby acquiring treated material, wherein the weight ratio of the grass seeds to the cover soil is 3:100 and the weight ratio of the plant ingredients to the cover soil is 4:100;

(21) C. Spreading the treated material on the slope and manually flattening, wherein the thickness of the treated material is 10 cm;

(22) D. Watering the slope covered with the treated material.

(23) On the 30th day after step D is finished, starting to measure the moisture content of the soil at 10 cm below the soil surface of No. 4 experimental plot for the first time, recording, and then repeating the measurement once per 30 days and recording (see Table 1 for the recorded data); in the 12th month after step G is finished, measuring the content of organic matter and nitrogen in the soil on the soil surface of No. 4 experimental plot, recording, and then repeating the measurement once per 12 months and recording (see table 2 for the recorded data).

Contrasting Embodiment 2: Successively Executing the Following Steps in No. 5 Experimental Plot

(24) A. Taking the soil on the construction site as cover soil, adding grass seeds into the cover soil, adding water, and uniformly stirring, thereby acquiring treated material, wherein the weight ratio of the grass seeds to the cover soil is 3:100;

(25) Executing the following steps identical to steps C and D in contrasting embodiment 1.

(26) On the 30th day after step D is finished, starting to measure the moisture content of the soil at 10 cm below the soil surface of No. 5 experimental plot for the first time, recording, and then repeating the measurement once per 30 days and recording (see table 1 for the recorded data); in the 12th month after step G is finished, measuring the content of organic matter and nitrogen in the soil on the soil surface of No. 5 experimental plot, recording, and then repeating the measurement once per 12 months and recording (see table 2 for the recorded data).

(27) The above Embodiments 1, 2 and 3, and contrasting embodiments 1 and 2 are started on the same day in April, 2010 and ended on the same day.

Contrasting Embodiment 3: Uniformly Scattering Grass Seeds as Heavy as the Grass Seeds in Embodiment 1 on the Slope Under the Natural State in No. 6 Experimental Plot

(28) And measuring the moisture content of the soil at 10 cm below the soil surface at the time of measuring the moisture content in other experimental plots and recording in Table 1; measuring the content of organic matter and nitrogen in the soil on the soil surface at the time of measuring the content in other experimental plots and recording in Table 2.

(29) TABLE-US-00001 TABLE 1 the moisture content (%) of the soil at 10 cm below the soil surface of the abandoned slag slope Month No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 May 10.2 10.8 10.5 9.9 9.6 7.8 June 10.9 11.7 11.2 10.6 10.0 8.3 July 12.2 12.9 11.5 11.9 11.5 9.7 August 11.9 12.6 12.0 11.6 11.4 9.4 September 11.2 11.8 11.6 10.8 10.7 8.9 October 10.5 11.1 10.7 10.3 10.1 8.0

(30) After the vegetation on the slope grows up, on the slope of the same slag disposal pit, the areas, in which the vegetation grows more excellent, are higher in moisture content of soil and higher in water retaining capacity, so that the good and bad conditions of the growth of the vegetation on the slope in each experimental plot can be measured by measuring and comparing the moisture content of the soil in each experimental plot.

(31) According to Table 1, the water contents of the surface soil in No. 1, No. 2, No. 3, No. 4 and No. 5 experimental plots are all far higher than that of the surface soil in No. 6 experimental plot, that is to say, as long as the cover soil is mixed with water, the water content of the surface soil is far higher than the water content of the original land surface soil, the cover soil after being mixed with water has excellent water retaining capacity, and the vegetation growing on the cover soil is better than that on the original and under natural state; the water contents of the surface soil in No. 1, No. 2 and No. 3 experimental plots are higher than the water contents of the surface soil in No. 4 and No. 5 experimental plots, that is to say, the vegetation growing on the cover soil added with the gelling material is better than that on the cover soil without the gelling material. The test proves that the vegetation on the cover soil added and mixed with the gelling material can grow well and the root system of the vegetation has an excellent water conservation function.

(32) TABLE-US-00002 TABLE 2 Conditions of Soil Nutrients on the Soil Surface of the Abandoned Slag Slope No. Measuring Year Organic Matter Nitrogen Percentage (%) No. 1 2011 2.34 0.128 2012 2.50 0.135 2013 2.58 0.126 No. 2 2011 2.36 0.091 2012 2.48 0.088 2013 2.54 0.082 No. 3 2011 2.36 0.091 2012 2.48 0.088 2013 2.54 0.082 No. 4 2011 2.25 0.081 2012 2.37 0.087 2013 2.51 0.091 No. 5 2011 2.01 0.105 2012 2.26 0.088 2013 2.38 0.079 No. 6 2011 1.57 0.154 2012 1.81 0.147 2013 1.73 0.165

(33) After the plants grow up, the dead leaves will rot into organic matters under the presence of water, following the alternation of seasons, and meanwhile, the organic matters also can be served as nutrient for supporting the growth of the plants, so that a local ecological system is formed, and thus, the contents of the organic matters of the soil on the soil surfaces of the experimental plots can be utilized to measure whether the vegetation in the experimental plots grow well.

(34) While growing, the plants will consume the nitrogen in soil, so that the growth condition of the plants also can be measured by detecting the change in nitrogen in soil.

(35) Thus, on the slope of the same slag disposal pit, the area, in which the vegetation grow well, is higher in organic matter content on the soil surface and is large in change in nitrogen in the soil.

(36) Therefore, Table 2 shows that the vegetation growing condition on the slope covered with the cover soil mixed with water and grass seeds is better than that of the vegetation which grow from the grass seeds directly scattered on the slope of the original land; furthermore, the vegetation on the treated material mixed with the gelling material are better than that growing on the treated material without the gelling material.

(37) According to the water and soil conservation and ecological restoration method of high and steep, abandoned slag piles at high elevation with large temperature difference in xerothermic drought valley provided by the invention, the gelling material is added into the cover soil, so that the treated material is prevented from falling into the gap of the slope, the quantity of the required cover soil is greatly reduced, the scale of taking the local cover soil is reduced, and the degree of damage to the local original ecological environment caused by taking the local cover soil is reduced; furthermore, the test proves that the growth of the vegetation on the cover soil which is mixed with water and then is mixed with the grass seeds is better than that of the vegetation on the slope on which the grass seeds are directly scattered under natural state, that is to say, after the cover soil is mixed, the growth of the vegetation will be benefited, and meanwhile, the root system has a water-retaining and soil-fixing function after the vegetation grow up, thus, the soil on the slope is kept wet, and the dead leaves of the plants will be rotten under the humid environment following the increasing of the year, thereby being capable of increasing the proportion of the organic matters in the soil year by year, and besides, the organic matters can supply nutrients for the growth of the plants, thereby being capable of forming an excellent ecological cycle, causing the growth of the vegetation on the treated slope to be better and better and further achieving the purpose of keeping the water and soil on the slope.

(38) The comparison of tests proves that the vegetation growing on the cover soil mixed with the gelling material are better than that growing on the cover soil without the gelling material, therefore adding the gelling material into the cover soil, mixing with water and then spreading the acquired treated material on the slope, and furthermore, in the preferred scheme, the soil on the slope can be effectively prevented from falling off and the growth of the vegetation on the slope can be benefited, by arranging multiple rows of barriers at intervals on the slope, thus, such a water and soil conservation method is suitable for the water and soil conservation of high and steep, abandoned slag piles at high elevation with large temperature difference in xerothermic drought valley.

(39) The key technology of above methods is that various materials are mixed and used for solving the problems of the method and technique for conserving soil and water and restoring the vegetation on the high and steep slope and large slag surface of the construction engineering slag disposal pit. The specific method is as follows: mixing trace gelling materials (cement, coal ash, clay, and the like) with local soil (sand soil or impurity soil), grass clippings, grass seeds, and the like, in different proportions for tens of groups, and then manually spreading on the side slope and steep slope of the slag disposal pit, thereby achieving the soil-fixing, slope-stabilizing, soil-conserving and water-conserving effects. Such a precision work aims to reduce the thickness of the cover soil on the slope and reduce the quantity of the taken or purchased soil (the water and soil conservation and vegetation ecological environment on the digging area will be certainly damaged by the soil taking and soil purchasing in any manner). The said precision work indicates taking the cover soil as the lime and cement mortar paved for a vertical wall of a house and causing the stirred mixed soil to form block or shell, thereby preventing all the cover soils from being shaken into the gaps of imbalanced block slag piles or being eroded by rainwater.

(40) The purpose of adding the trace gelling material into the loosening sand particle soil is to increase the fine particle components or content and to cause the fine particles to be evenly wrapped on the coarse particles in the manner of stirring and have a condensation function, thereby achieving the purposes of fixing the soil and solving the soil erosion problems, such as, the soil particles are loosening, the structural property is poor, the fine dust particles are easily blown away by the strong wind, the slope cannot resist rainwater wash, and the like. The trace mixing indicates that the mixing proportion of the other gelling material should be controlled within the scope of 1%-5%, except for the mixing proportion of the clay as high as 10%; namely, the soil should be conserved while the soil texture and the acid-base property of the soil are not greatly changed.

(41) Mixing the grass clippings indicates cutting the collected or purchased weeds into the 5-10 cm long grass clippings, and then manually dry mixing with a shovel or adding a defined amount of water or mixing with the gelling material, and then paving onto the slope. By mixing the grass clippings, on one hand, the grass clippings have the (connecting and soil-fixing) function of reinforcing ribs in the soil; on the other hand, when the grass seeds grow, the mixed grass clippings are rotten and formed into organic (humus) matters, and after rotting in the soil, the grass clippings are served as fertilizer and are formed into fine cavities, thereby being beneficial to the growth of other plants. The fresh grass clippings are not the unique organic treated material, and while governing the sloping fields around the house, the local farmer can adopt organic refuses, such as, mixed peel, abandoned vegetable leaves, and the like, which have the same function as the grass clippings.

(42) The purpose of adding water and manually mixing is to increase the coagulation of the loosening sand particle soil, cause the soil to be more evenly paved on the slope surface of the steep slope and cause the coarse particles not to easily dissociate, fall and separate. The mixing contains the experimental sets, such as, singly mixing with water, mixing with the gelling material, mixing with the grass clippings and the gelling material, and the like, and the experimental set of mixing the grass clippings without water.

(43) According to the above method, compared with the slope surface soil without mixing, the surface soil on the cover soil after being stirred or mixed contains more nutrients (e.g., organic matters and fertilizer). Furthermore, the proportion of the organic matters is obviously increased with time; the nitrogen fertilizer proportion is gradually reduced with time and the quantity of the mixture, but it is in little fluctuation; and the change in phosphorus containing proportion is not obvious. The change in the content and proportion of the soil fertility indicates that, in the absence of manual fertilization and fertilizing, some element nutrients contained in the soil are consumed by the plant growth. If the surface of the slag disposal pit is used for restoring cultivation, the fertilization and fertilizing applying measures should be taken for increasing the soil fertility. The conversion from ecological restoration under manual intervention to self-adapting, self-regulating and natural growing ecological restoration can be realized.

(44) According to the above method, anyone who is willing to participate in ecological management can adopt the convenient, simple and economical method for positively implementing water and soil conservation and ecological restoration. All the farmers and land contract operators can adopt such a simple and practicable method for improving the slope cropland, hanger, grassland or the vegetation planting environment around the house and turning any lands and slope fields into fertile farmlands and gardens.

(45) Any alteration, equivalent replacement and improvement without departing from the spirit and principle of the invention all should be in the protection scope of the invention.