A precise vegetation configuration method for preventing and controlling soil and water loss on slopes

Abstract

The present invention relates to a method for precise vegetation configuration for preventing and controlling soil and water loss on slopes, which includes collecting undisturbed root-soil complex samples on natural grassland slopes and bare slopes, measuring the relative soil detachment rate to characterize the slope erosion characteristics; simultaneously measuring the corresponding soil physical and chemical properties to characterize the soil texture; then measuring the root length density contained in the undisturbed root-soil complex; analyzing the relationship between the relative soil detachment rate and the root length density, analyzing the influence of soil texture on the relationship between the two, distinguishing high-texture soil and low-texture soil, and respectively exploring the relationship between the relative detachment rate and the root length density of high-texture soil and low-texture soil; wherein, the root length density corresponding to high-texture soil is 58.02 - 160.00 km·m<supgt;-3< / supgt>; the estimated corresponding herb cover is 32.02% - 51.56%; the root length density of low-texture soil ≥ 184.57 km·m<supgt;-3< / supgt>, and the corresponding herb cover is 55.14%; for low-texture soil, 3.3 kg·m<supgt;-3< / supgt> - 3.5 kg·m<supgt;-3< / supgt> of straw with a length of 8 - 10 cm is mixed in the 0 - 10 cm soil layer before sowing.

Description

Technical Field

[0001] The present invention relates to the technical field of soil and water conservation, and more particularly to a method for accurately configuring vegetation for preventing and controlling soil and water loss on slopes. Background Art

[0002] Plants can effectively reduce soil erosion and increase the stability of slope structures, and have become a commonly used measure in the process of slope ecological restoration in my country. In the process of slope greening, herbaceous plants are often laid out in the form of sowing grass seeds. Before germination and in the early stage of plant growth, the reduction of soil erosion by vegetation is difficult to achieve the expected goal, and even promotes erosion, which is very likely to cause soil and water loss, thus affecting the quality of the main project and the stability of the slope. Therefore, the prevention and control of slope soil erosion in the early stage of plant measures is one of the key points of ecological restoration. In addition, the underlying soil conditions of different slopes vary greatly. How to identify different types of slopes and accurately configure corresponding plant measures has become the key to current ecological restoration and soil and water conservation work.

[0003] At present, the layout of herbaceous plants in the process of slope ecological restoration mostly adopts uniform density and coverage. However, different soil textures have different anti-erosion properties. Therefore, the vegetation coverage required for slopes with different soil textures is different. For slopes with better texture, only fewer vegetation measures are needed to prevent and control slope soil erosion. However, how to define slopes with different soil textures and how to achieve accurate configuration of measures for various slopes are problems that technical personnel in this field urgently need to solve. Summary of the invention

[0004] To this end, the purpose of the present invention is to propose a method for accurately configuring vegetation for preventing and controlling soil erosion on slopes, which can define slopes with different soil textures and achieve accurate configuration of measures for various slopes.

[0005] The technical solution of the present invention is a method for accurately configuring vegetation for preventing and controlling soil erosion on slopes, comprising the following steps:

[0006] S1. Collect original root-soil complex samples on natural grassland slopes and bare land slopes, and measure the relative soil separation rate (RSD) to characterize the slope erosion characteristics; at the same time, measure the corresponding soil physical and chemical properties to characterize the soil texture;

[0007] S2. On the basis of completing S1, determine the root length density contained in the original root-soil complex;

[0008] S3. Analyze the relationship between relative soil separation rate and root length density, analyze the influence of soil texture on the relationship between the two, distinguish high-texture soil from low-texture soil, and explore the relationship between relative separation rate and root length density of high-texture soil and low-texture soil respectively;

[0009] Among them, the relative soil detachment rate adopts RSD ≤ 0.016, and the corresponding root length density for high-texture soil is 58.02 - 160.00 km·m -3 ; According to the functional relationship between herbaceous coverage and root length density, the corresponding estimated herbaceous coverage is 32.02% - 51.56%;

[0010] The root length density of low-texture soil ≥ 184.57 km·m -3 , and the corresponding herbaceous coverage is 55.14%;

[0011] For low-texture soil, before sowing, 3.3 kg·m -3 -3.5 kg·m -3 of straw with a length of 8 - 10 cm needs to be incorporated into the soil layer of 0 - 10 cm.

[0012] According to the technical solution of the present invention, the physical and chemical properties of the soil in S1 include bulk density and organic matter.

[0013] According to the technical solution of the present invention, the high-texture soil in S3 has a bulk density greater than or equal to 1.30 g·cm -3 , or an organic matter content greater than or equal to 11.76 g·kg -1 ; when this is the case, only a small amount of roots in the soil can achieve a low detachment rate; for low-texture soil with a bulk density less than 1.30 g·cm -3 , or an organic matter content less than 11.76 g·kg -1 , a large number of roots in the soil are required to achieve a low detachment rate.

[0014] According to the technical solution of the present invention, in S1, undisturbed root-soil complex samples are collected on natural grassland slopes and bare slopes, the soil detachment rate is measured by a soil detachment test, and the relative soil detachment rate RSD is obtained by using the ratio of the soil detachment rate of grassland SDR 草 and bare slope SDR 裸 , which is expressed by formula (1) and is used to characterize the erosion characteristics of the slope. The lower the relative soil detachment rate, the stronger the erosion resistance;

[0015]

[0016] At the same time, the soil bulk density is measured by the drying method, the soil organic matter is measured by the external heating method with potassium dichromate, and the soil texture is characterized by the bulk density and organic matter.

[0017] According to the technical solution of the present invention, after the soil detachment test in S1 is completed, in S2, the root-soil complex samples are washed and collected, and the root length density is obtained by scanning.

[0018] According to the technical solution of the present invention, the root length density is the ratio of the root length to the volume of the sampling ring cutter, and is expressed by formula (2);

[0019]

[0020] In the formula, RLD is the root length density (km·m -3 ), RL is the root length parameter (km), and V 刀 is the volume of the circular ring cutter (m 3 ).

[0021] According to the technical solution of the present invention, the functional relationship between the herbaceous coverage and the root length density is expressed by formula (3):

[0022]

[0023] In the formula: V is the herbaceous coverage (m 2 ), and RLD is the root length density (km·m -3 ).

[0024] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following technical effects:

[0025] By analyzing the influence of soil properties on the erosion reduction effect of plant roots, the present invention proposes a classification standard for different texture soils, and then provides different vegetation configuration schemes for slopes of different texture soils, which can provide support for the precise configuration of vegetation in the process of slope ecological restoration and is beneficial to saving engineering costs.

[0026] For low-texture soil, before sowing grass seeds, about 3.5 kg·m of straw with a length of about 9 cm is mixed into the 0-10 cm soil layer to prevent slope erosion in the initial stage of plant growth; then a herbaceous coverage of more than 55.14% is configured to achieve the purpose of erosion reduction in the whole cycle of ecological restoration. -3 BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a relationship diagram of the relative soil detachment rate and the root length density of the present invention;

[0028] Figure 2 is a relationship diagram of the relative soil detachment rate and the root length density in high-texture soil of the present invention;

[0029] Figure 3 is a schematic diagram of the straw erosion reduction test;

[0030] Figure 4 is a schematic diagram of the ecological restoration configuration of different texture soils. DETAILED DESCRIPTION OF THE INVENTION

[0031] ​In the prior art, during the slope ecological restoration process, the layout of herbaceous plants usually adopts a unified density and coverage. However, due to different soil textures, the anti-erosion properties of the soil itself vary, and the vegetation coverage required for slopes with different soil textures is different. For slopes with better textures, only a few vegetation measures are needed to achieve the purpose of preventing slope soil erosion, while the unified density and coverage increase unnecessary engineering costs.

[0032] In view of this, the present invention provides a precise vegetation configuration method for preventing soil and water loss on slopes, which measures the relative soil detachment rate to characterize the slope erosion characteristics, and determines the corresponding root length density and soil texture (bulk density and organic matter); further, analyzes the influence of soil texture on the relationship between the relative soil detachment rate and the root length density, and finds that when the bulk density is higher than or equal to 1.30 g·cm -3 , or the organic matter is higher than or equal to 11.76 g·kg -1 in the soil, the addition of a small amount of roots can also achieve good erosion reduction effects. The slopes are divided into two categories: high-texture soil and low-texture soil through the above soil parameters; further, for the high-texture soil slopes, when the herb coverage reaches 32.02 - 51.56%, a relatively low detachment rate can be achieved to meet the erosion reduction requirements; for the low-texture soil slopes, before sowing grass seeds, wheat straw with a length of about 9 cm is mixed in the 0 - 10 cm soil layer, and the mixing amount is about 3.5 kg·m -3 to prevent large erosion during the initial growth stage, and then a herb coverage of more than 55.14% is configured to achieve full-cycle erosion reduction of the slope.

[0033] The present invention solves the problem of precise configuration of plant measures during the slope ecological restoration process of soils with different textures. Taking natural grasslands as the research object, using the influence of soil properties on the root erosion reduction effect, it proposes the classification criteria for high-texture and low-texture soils, then configures measures for each type of texture slope, and proposes the herb coverage of the corresponding slope to achieve precise layout. On the one hand, according to the differences in soil properties, it precisely configures the vegetation measures on the slope during the ecological restoration process, effectively saving the ecological restoration cost and providing stronger guidance for the project. On the other hand, it proposes the prevention technology for soil erosion during the initial growth stage of plants on low-texture soil slopes, and obtains the minimum herb coverage to achieve soil erosion prevention of the slope, realizing full-cycle soil erosion prevention.

[0034] Specifically, the method includes the following steps:

[0035] S1. Collect undisturbed root-soil complex samples on natural grassland slopes and bare lands, measure the relative soil detachment rate to characterize the slope erosion characteristics; at the same time, measure the physical and chemical properties (bulk density, organic matter) of the corresponding soil to characterize the soil texture;

[0036] S2. On the basis of completing Step 1, measure the root length density in the undisturbed root-soil complex;

[0037] S3. Analyze the relationship between the relative soil detachment rate and the root length density, identify the influence of soil properties on this relationship, propose the classification criteria for different soil textures, and classify soils with a bulk density greater than or equal to 1.30 g·cm -3 , or an organic matter content greater than or equal to 11.76 g·kg -1 as high-texture soils, and the remaining soils as low-texture soils;

[0038] Under high-texture soil conditions, a relatively low relative soil detachment rate ≤ 0.016 can be achieved with fewer plant roots, corresponding to a root length density of 58.02 - 160.00 km·m -3 , and a corresponding herbaceous coverage of 32.02% - 51.56%.

[0039] Under low-texture soil conditions, when the root length density exceeds 184.57 km·m -3 , that is, when the herbaceous coverage reaches 55.14%, can its relatively low relative soil detachment rate be maintained;

[0040] Since under low-texture soil conditions, a good anti-erosion effect cannot be exerted in the initial stage of plant growth, about 9 cm long straw with a quantity of 3.5 kg·m -3 should be incorporated into the 0 - 10 cm soil layer before sowing to prevent significant soil erosion on the slope surface during the initial growth stage.

[0041] More specifically, in S1, natural grasslands with taproots and fibrous roots, and bare lands are taken as the research objects. Six 1×1 m quadrats are randomly arranged on each slope surface. Using a circular knife with a diameter of 10 cm and a height of 5 cm, root-soil complex samples within the quadrats are collected. The soil detachment rate is measured using the soil detachment test. The relative soil detachment rate RSD (Equation 1) is obtained by taking the ratio of the SDR of the grassland 草 and the SDR of the bare land 裸 to characterize the erosion characteristics of the slope surface. The lower the relative detachment rate, the higher the soil anti-erosion ability; at the same time, undisturbed soil samples are collected using a circular knife with a diameter of 5.5 cm and a height of 5 cm, and the soil bulk density is measured by the oven-drying method; additional soil samples are collected around the root-soil complex sampling points, and the soil organic matter is measured using the external heating method with potassium dichromate. The soil texture is characterized based on the two parameters of bulk density and organic matter;

[0042]

[0043] After the soil separation test, the root length density in a circular ring cutter with a diameter of 10 cm and a height of 5 cm was obtained. The root-soil complex sample was placed on a 2-mm sieve for rinsing and then collected. The root length was obtained using WinRHIZO software, and the ratio of the root length to the volume of the circular ring cutter was the root length density (Equation 2).

[0044]

[0045] In the formula, RLD is the root length density (km·m -3 ), RL is the root length parameter (km), and V 刀 is the volume of the circular ring cutter (m 3 ).

[0046] Furthermore, the relationship between the relative soil separation rate and the root length density was analyzed. First, using the empirical frequency method, it was found that when the relative soil separation rate RSD ≤ 0.016, it would not change significantly with the increase in root density. Second, for most sample points, the relative soil separation rate decreased exponentially with the root length density and quickly reached a stable state (RSD ≤ 0.016). However, there were some sample points where, at relatively low root length densities, the soil separation rate was still low, which did not conform to the characteristics of most sample points. By analyzing the root length density, soil bulk density, and organic matter corresponding to each sample point, it was found that these sample points with relatively low root length densities and low separation rates had better soil textures.

[0047] From Figure 1 the relationship diagram between the relative soil separation rate and the root length density in -3 , for fibrous root grasslands, when the root length density was less than 184.57 km·m -3 , but there was soil texture with a bulk density higher than 1.30 g·cm -1 , or an organic matter higher than 10.74 g·kg -3 , the same relatively low separation rate could be achieved; for taproot grasslands, when the root length density was less than 141.502 km·m -3 , but there was soil texture with a bulk density higher than 1.27 g·cm -1 , or an organic matter higher than 11.76 g·kg -1 , or the ratio of root mass density to root length density RMD / RLD higher than 1.17 kg·km -1 , the same relatively low separation rate could be achieved.

[0048] Based on the research results of fibrous root and taproot plots and following the principle of taking the maximum value, when the bulk density was higher than (including) 1.30 g·cm -3 , or the organic matter was higher than (including) 11.76 g·kg -1, only a relatively low root density is required to achieve a low detachment rate, and it is classified as high-texture soil. For other texture soils, it is classified as low-texture soil.

[0049] For high-texture soil, analyze the variation characteristics of its relative soil detachment rate with root length density (see Figure 2 ), and it is found that when the root length density is 58.02 - 160.00 km·m -3 , a relatively low relative soil detachment rate ≤ 0.016 can be achieved. According to the functional relationship between vegetation coverage and root length density (Equation 3), the corresponding herbaceous coverage is estimated to be 32.02% - 51.56%.

[0050] That is, for high-texture soil, only by configuring a herbaceous coverage of 32.02% - 51.56% can a good anti-erosion effect be achieved.

[0051]

[0052] For low-texture soil, the relative soil detachment rate decreases exponentially with the increase of root length density and quickly reaches a stable state (RSD ≤ 0.016). Based on the intersection point of RSD = 0.016 and the curve of the relative soil detachment rate changing with root length density, the corresponding root length density is obtained. When the root length density is higher than this critical value, the relative soil detachment rate RSD ≤ 0.016, reaching a stable state. For fibrous root grasslands, this critical root length density is 141.52 km·m -3 , and for taproot grasslands, the critical root length density is 184.57 km·m -3 . Based on the principle of taking the maximum value, when the root length density is higher than 184.57 km·m -3 , with a corresponding herbaceous coverage of 55.14%, a relatively low relative soil detachment rate and a good anti-erosion effect can be achieved.

[0053] However, herbaceous plants can only exert a stable erosion-reducing performance after growing for 170 days. During the initial stage of plant growth from seeding to 170 days, the vegetation does not play a good role in reducing soil loss;

[0054] See Appendix Figure 3 , combined with relevant wheat straw blending experiments:

[0055] Mix 1.5 kg·m -3 , 2.5 kg·m -3 , 3.5 kg·m -3 and 4.5 kg·m -3 of wheat straw with lengths of 4 cm, 9 cm and 14 cm into the 0 - 10 cm soil layer of the bare slope, and then conduct slope rainfall experiments. It is found that when the straw length is 9 cm and the straw blending amount is 3.5 kg·m -3has the lowest sediment yield at this time, which can reduce the sediment yield on the slope by 63.46%. Therefore, this measure can be used as an anti-erosion measure for the slope during the sowing period and the initial stage of plant growth. Of course, the straw length is 9 cm and the straw mixing amount is 3.5 kg·m -3 is the optimal state. In practice, the straw length can be about 9 cm and the straw mixing amount can be 3.5 kg·m -3 .

[0056] Therefore, to effectively prevent soil erosion in the initial growth stage, it is necessary to mix 3.5 kg·m of straw with a length of 9 cm in the 0-10 cm soil layer -3 , and then configure herbaceous plants with corresponding coverage, see Figure 4 . In addition, the erosion reduction effect of the straw can be maintained for about 300 days, which is longer than the interval period of about 170 days when the erosion reduction function in the initial stage of plant growth cannot be stably exerted. As the plants grow, the erosion reduction effect of the plants gradually increases, and the measure of "vegetation + straw" will have greater erosion reduction potential. As the straw gradually decomposes in the later stage, although the ability to reduce soil erosion weakens, the nutrients released after decomposition further promote the growth of the vegetation, contribute to the exertion of the vegetation's anti-erosion function, and still can achieve the purpose of controlling soil erosion on the slope and achieving the whole-cycle erosion reduction of ecological restoration.

[0057] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A precise vegetation configuration method for preventing and controlling soil and water loss on slopes, characterized in that, Including the following steps: S1. Collect undisturbed root-soil complex samples on the slopes of natural grasslands and bare lands, measure the relative soil detachment rate (RSD) to characterize the slope erosion characteristics; at the same time, measure the corresponding soil physical and chemical properties to characterize the soil texture; S2. On the basis of completing S1, measure the root length density contained in the undisturbed root-soil complex; S3. Analyze the relationship between the relative soil detachment rate and the root length density, analyze the influence of soil texture on this relationship, distinguish high-texture soils and low-texture soils, and respectively explore the relationship between the relative detachment rate and the root length density of high-texture soils and low-texture soils; Among them, the relative soil separation rate adopts RSD ≤ 0.016, and the corresponding root length density for high-texture soil is 58.02 - 160.00 km·m -3 ; According to the functional relationship between herbaceous coverage and root length density, the corresponding herbaceous coverage is estimated to be 32.02% - 51.56%; The root length density of low-quality soil ≥ 184.57 km·m -3 , corresponding to a herbaceous coverage of 55.14%; For low-quality soil, 3.3 kg·m to 3.5 kg·m of straw with a length of 8 - 10 cm needs to be incorporated into the 0 - 10 cm soil layer before sowing. -3 -3.5 kg·m -3 ; The soil physical and chemical properties in S1 include bulk density and organic matter; The high-quality soil in S3 has a bulk density greater than or equal to 1.30 g·cm -3 , or an organic matter content greater than or equal to 11.76 g·kg -1 . When only a small amount of roots are present in the soil, a relatively low separation rate can be achieved; the low-quality soil has a bulk density less than 1.30 g·cm -3 , or an organic matter content less than 11.76 g·kg -1 . When a large amount of roots are present in the soil, a relatively low separation rate can be achieved.

2. The vegetation precise configuration method for preventing and controlling soil and water loss on slopes according to claim 1, characterized in that, In S1, undisturbed root-soil complexes were collected from natural grassland slopes and bare land slopes. The soil detachment rate was measured using the soil detachment test, and the relative soil detachment rate (RSD) was obtained by taking the ratio of the soil detachment rate of the grassland SDR 草 and that of the bare land SDR 裸 as expressed by Equation (1). The RSD was used to characterize the erosion characteristics of the slope. The lower the RSD, the stronger the erosion resistance At the same time, use the oven-drying method to measure the soil bulk density, use the external heating method with potassium dichromate to measure the soil organic matter, and use the bulk density and organic matter to characterize the soil texture.

3. A method for precise vegetation configuration for preventing and controlling soil and water loss on slopes according to claim 1, characterized in that, After the soil detachment test in S1, in S2, the root-soil complex samples are washed and collected, and the root length density is obtained by scanning.

4. A method for precise vegetation configuration for preventing and controlling soil and water loss on slopes according to claim 3, characterized in that, The root length density is the ratio of the root length to the volume of the sampling ring cutter, and is expressed by Equation (2); wherein, RLD is the root length density (km·m -3 ), RL is the root length parameter (km), V 刀 is the volume of the circular cutting ring (m 3 ).

5. A method for precise vegetation configuration for preventing and controlling soil and water loss on slopes, according to claim 4, characterized in that The functional relationship between the herb cover and the root length density is expressed by Equation (3): Where: V is the herb coverage (m 2 ), RLD is the root length density (km·m -3 ).

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