Ecological restoration method for alpine meadow

Abstract

The invention provides an alpine meadow ecological restoration method, which comprises the following steps: evaluating the optimal vegetation coverage range of a target area, and obtaining the optimal vegetation coverage range according to the soil moisture vegetation bearing capacity; and acquiring the current vegetation coverage of the target area, and if the current vegetation coverage is not in the optimal vegetation coverage range, regulating and controlling the vegetation coverage to be in the optimal vegetation coverage range by manually changing the underlying surface. According to the method, firstly, whether the current coverage of a meadow steppe target area exceeds the optimal vegetation coverage range or not is evaluated, the meadow coverage is reduced to be within the optimal vegetation coverage range by changing the underlying surface, and the vegetation coverage is properly reduced on the premise of guaranteeing the ecological function, so that excessive consumption of soil moisture by vegetation is reduced; the soil structure and infiltration capacity are improved by manually changing the underlying surface, the supply amount of rainfall to soil water is increased, and the soil water balance of the meadow steppe is improved, so that the soil water storage amount is increased, and the drought is effectively relieved.

Description

TECHNICAL FIELD

[0001] The present application relates to an ecological restoration method, in particular to a vegetation ecological restoration method. BACKGROUND

[0002] At present, the meadow steppe in the arid and semi-arid region is facing a serious drought problem. The annual precipitation in this region is less than 400 mm, and the precipitation is unevenly distributed in the year, with distinct dry and wet seasons, which makes it difficult for the soil moisture condition to meet the normal growth needs of the vegetation. At the same time, the excessive consumption of soil moisture by the vegetation aggravates the soil drought.

[0003] In the prior art, in order to improve the ecological condition of the meadow steppe in the semi-arid region, it is generally believed that the coverage of the meadow should be increased as much as possible, because the increase of the coverage will increase the green area, and if the coverage continues to decrease, the degree of drought will increase and the desertification will be aggravated. Therefore, in the prior art, plowing machinery is usually used to turn over the target grassland at the beginning of the growing season, and artificial water supplement and grass seed sowing are also used. The water seeps into the deep soil, and after the soil water content is increased, the sown pasture will grow more luxuriantly. Although this method can supply soil moisture and increase vegetation biomass to a certain extent, it has the problems of large investment of manpower and material resources, and significant disturbance to the original ecological environment.

[0004] Secondly, the alpine meadow region located in the semi-arid zone has sensitive and fragile vegetation ecology, so if the ecological restoration work is not accurate enough, it will have the opposite effect of damaging the ecology. SUMMARY

[0005] The present application provides an alpine meadow ecological restoration method, which is simple and easy to operate, and has moderate intervention.

[0006] Technical scheme: The present application provides an alpine meadow ecological restoration method,

[0007] The optimal vegetation coverage range of the target region is evaluated, and the optimal vegetation coverage range is obtained according to the soil moisture vegetation carrying capacity;

[0008] The current vegetation coverage of the target region is obtained, and if the current vegetation coverage is not within the optimal vegetation coverage range, the vegetation coverage is adjusted to be within the optimal vegetation coverage range by changing the underlying surface artificially.

[0009] In one implementation, the optimal vegetation coverage range is set to be not more than the soil moisture vegetation carrying capacity.

[0010] In one implementation, the optimal vegetation coverage range is set to be not more than 80% of the coverage value calculated according to the soil moisture vegetation carrying capacity.

[0011] In one implementation, the optimal vegetation coverage range is set to a level of vegetation coverage that does not exceed a coverage value of the target area within a set time.

[0012] In one implementation, the calculation of the soil water vegetation carrying capacity includes the following steps:

[0013] S101, calculate the effective soil water storage capacity:

[0014] According to the soil effective depth, the soil profile is divided into K layers, and the soil profile is divided into K layers according to a mm interval, and the soil profile is divided into K layers. k The soil volume water content of the kth layer is Wk, and the soil water storage capacity of the kth layer is Wk. k

[0015] W k = θ k ×a (1)

[0016] S102, calculate the average soil water storage capacity ASWS in the effective soil depth:

[0017]

[0018] In the formula, the unit of the average soil water storage capacity ASWS is mm;

[0019] S103, calculate the minimum value of the average soil water storage capacity:

[0020] Record the total number of n times of the average soil water storage capacity ASWS measured in the entire growing season, and the time from early to late is W1, W2…, Wn. n MVASWS is the minimum value of the average soil water storage capacity:

[0021] MVASWS = min (W1, W2…, Wn) (3) n

[0022] S104, calculate the soil water vegetation carrying capacity:

[0023] The optimal fitting model F(x) is obtained by fitting the vegetation coverage in different sample plots and the corresponding minimum value of the average soil water storage capacity MVASWS, and the independent variable is the soil water storage capacity W i , and the dependent variable is the vegetation coverage C, that is:

[0024] C = F(W i ) (4)

[0025] If W m is the soil water storage capacity corresponding to the wilting point, substitute the above fitting model, then the soil water vegetation carrying capacity SWCCV is

[0026] SWCCV = F(W m ) (5).​​

[0027] In one implementation, the method of adjusting the vegetation coverage to the optimal vegetation coverage range by changing the underlying surface includes:

[0028] calculating the difference Δ between the optimal vegetation coverage S and the current vegetation coverage C, and when the difference Δ is less than 0, intervening by human; when the difference Δ is not less than 0, no need to adjust:

[0029] Δ = S - C (6)

[0030] In the formula, S is the optimal vegetation coverage, and C is the current vegetation coverage.

[0031] In one implementation, the method of adjusting the vegetation coverage to the optimal vegetation coverage range by changing the underlying surface includes:

[0032] calculating the difference Δ between the optimal vegetation coverage S and the current vegetation coverage C, and the ratio of the current vegetation coverage C, thereby calculating the area ratio of the underlying surface to be changed:

[0033] δ = Δ / C (7).

[0034] In one implementation, the method of changing the underlying surface by human includes: plowing and turning over the soil in the target area, and paving the gravel blocks on the surface of the furrow to form a gravel belt, and calculating the distance L between adjacent gravel belts:

[0035] L = B / δ (8)

[0036] In the formula, B is the width of the gravel belt.

[0037] The gravel belt is plowed along the contour direction of the meadow steppe, and the length of the furrow is consistent with the length of the meadow of the target area.

[0038] In one implementation, the plowing and turning over of the soil is performed by a micro tiller or by a yak.

[0039] Beneficial effects: 1. The present application first evaluates whether the current coverage of the target area of the meadow steppe is beyond the optimal vegetation coverage range, and reduces the meadow coverage to the optimal vegetation coverage range by changing the underlying surface, which is different from the method of blindly increasing the coverage to promote the growth of vegetation in the prior art. The present application mainly includes two core measures: one is to appropriately reduce the vegetation coverage under the premise of guaranteeing the ecological function, so as to reduce the excessive consumption of soil moisture by the vegetation; the other is to improve the soil structure and infiltration capacity by changing the underlying surface by human, to increase the amount of rainfall to the soil water, and to improve the soil water balance of the meadow steppe, thereby increasing the soil water storage capacity and effectively alleviating the drought;

[0040] 2、The application obtains the area ratio of the underlying surface that needs to be changed by calculating the ratio of the difference between the optimal vegetation coverage and the current vegetation coverage and the current vegetation coverage, so as to accurately perform the artificial intervention of reducing the coverage, quantitatively restore the ecological index of the alpine meadow and steppe in a targeted manner, and avoid ecological damage caused by blind restoration, so as to overcome the sensitive problems of the meadow and steppe;

[0041] 3、The application changes the underlying surface by plowing and laying a gravel layer, reduces the direct evaporation of soil water, and uses the small specific heat capacity of gravel to obtain condensed water to supplement soil water, so as to be a more scientific and adaptive ecological restoration strategy, and to guarantee the long-term stability and sustainable development of the ecological system;

[0042] 4、In the arid and semi-arid region, water resources of the meadow and steppe are limited, the application improves the soil infiltration capacity by plowing, and can naturally supplement water to the vegetation after precipitation, compared with artificial water supplement, the method can improve the meadow ecology in a large area, coordinate the water use contradiction between soil water and vegetation growth, reduce the evaporation of surface water, increase the soil water storage capacity, and promote the sustainable development of the soil water and vegetation ecological system. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a schematic diagram of a plowing area;

[0044] Figure 2 It is a schematic diagram of a plowing process. DETAILED DESCRIPTION

[0045] In order for those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0046] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0047] In the traditional meadow prairie ecological restoration practice, the conventional approach generally focuses on maximizing vegetation coverage and biomass in order to quickly achieve the effect of land greening and soil and water conservation. These methods mainly include but are not limited to: full plowing and large-area sowing of grass seeds in the early growing season, high-density supplemental seeding by air seeding, and irrigation to maintain high biomass. However, the above methods significantly disturb the original ecological environment, and the alpine meadow is located in the semiarid zone, with sensitive and fragile vegetation ecology, therefore, the ecological restoration work must be accurate to avoid adverse effects and cause ecological damage.

[0048] Based on this, the present application provides an alpine meadow ecological restoration method:

[0049] S100, evaluate the optimal vegetation coverage range of the target area, the optimal vegetation coverage range is obtained according to the soil moisture vegetation carrying capacity.

[0050] The optimal vegetation coverage range is set to not exceed the soil moisture vegetation carrying capacity, so as to avoid excessive consumption of water in the soil by vegetation. For example, the optimal vegetation coverage range of the meadow is not more than 80% of the soil moisture vegetation carrying capacity.

[0051] As a prerequisite for this scheme, the soil moisture vegetation carrying capacity of the target area needs to be calculated first. Specifically, the process of calculating the soil moisture vegetation carrying capacity includes the following steps:

[0052] S101, calculate the effective soil water storage capacity:

[0053] First, layer according to the effective depth of soil, the effective depth of soil refers to the maximum soil depth that the root system can obtain water when the plant grows normally. In an example, in order to improve the calculation accuracy, layering is performed at an interval of a mm, and the soil profile is divided into K layers, θ k The soil volume water content of the kth layer is θ k, and therefore the soil water storage capacity W k of the kth layer is W k = θ k × a (1≤k≤K, k K is an integer set):

[0054] W k = θ k ×a (1)

[0055] In the formula, the smaller the value of a, the more accurate the calculation result of the soil water storage capacity. Usually a is 100 or 200;

[0056] S102, calculate the average soil water storage capacity ASWS within the effective depth of soil:

[0057] ​

[0058] In the formula, the unit of the average soil water storage ASWS is mm;

[0059] S103, calculate the minimum value of the average soil water storage:

[0060] Record the total of n times of the average soil water storage ASWS measured in the entire growing season, in order of time from early to late, W1, W2…, Wn. n (n≥3, ), MVASWS is the minimum value of the average soil water storage:

[0061] MVASWS = min(W1, W2…, Wn) (3) n

[0062] S104, calculate the soil water vegetation carrying capacity:

[0063] The optimal fitting model F(x) is obtained by fitting the vegetation cover in different sample plots and the corresponding minimum value of the average soil water storage MVASWS. In order to ensure the uniqueness of the fitting model, F(x) must be a monotonic function. Wherein, the independent variable of the model is the soil water storage W i , and the dependent variable is the vegetation cover C, that is:

[0064] C = F(W i ) (4)

[0065] If W m is the soil water storage corresponding to the wilting point, substitute it into the above fitting model, then the soil water vegetation carrying capacity SWCCV is:

[0066] SWCCV = F(W m ) (5)

[0067] Wherein, the soil water storage W m corresponding to the wilting point is measured by biological method, that is, by planting barley seedlings, the soil water content when the barley seedlings wilt due to water shortage and cannot be recovered by watering is measured. When the soil water content of different soil layers is this value, then the soil water storage at this time is W m .

[0068] In addition, as another alternative for evaluating the optimal vegetation cover range of the target area, the optimal vegetation cover range is set to be the level value of the vegetation cover in the target area set time, that is, the result of ecological environment succession. The optimal vegetation cover range is determined according to the actual growth of different regions of meadow steppe, which has spatial difference and needs to be determined according to specific circumstances. The set time here refers to all the years from the beginning of obtaining observation data to now, which should be at least more than 5 years, and the longer the time, the more accurate the mean value.

[0069] ​S200, obtaining the current vegetation coverage of the target area, and if the current vegetation coverage is not within the optimal vegetation coverage range, changing the underlying surface to regulate the vegetation coverage to be within the optimal vegetation coverage range.

[0070] Based on the above setting of the optimal vegetation coverage range, the method for determining whether the current vegetation coverage is within the optimal vegetation coverage range is not limited, as long as the relationship between the soil moisture vegetation carrying capacity and the vegetation coverage under the current state can be obtained through the determination, and whether human intervention is needed to adjust the vegetation coverage to be within the optimal vegetation coverage range is determined based on the relationship.

[0071] Firstly, whether ecological restoration is needed can be preliminarily determined by human judgment. During the period when the soil water storage reaches the minimum value in the growing season, the meadow does not show the phenomenon of yellowing leaves and stopping growth, and the vegetation state is evaluated as healthy state, without human intervention; otherwise, if the meadow shows the phenomenon of yellowing leaves and stopping growth during this period, the vegetation state is set as unhealthy state, and human intervention is needed.

[0072] Secondly, whether ecological restoration is needed can be accurately determined by accurate calculation. The method for determining whether the current vegetation coverage is within the optimal vegetation coverage range can be that the difference between the soil moisture vegetation carrying capacity and the current vegetation coverage is calculated, and when the difference is less than 0, human intervention is needed; when the difference is not less than 0, human intervention is not needed.

[0073] Specifically, the current vegetation coverage C of the grassland can be estimated by visual estimation method, and whether the current vegetation coverage is within the optimal vegetation coverage range is determined, and the difference Δ between the optimal vegetation coverage S and the current vegetation coverage C is calculated.

[0074] If Δ≥0, it indicates that the current vegetation growth state is normal, and human intervention is not needed; if Δ<0, it indicates that the vegetation growth state is unhealthy, and the number of vegetation exceeds the carrying limit of soil water, and human intervention is needed to control soil drought. The calculated difference can quantitatively serve the subsequent ecological restoration work, and realize quantitative and accurate ecological restoration work.

[0075] For example, the vegetation coverage is regulated to be within the optimal vegetation coverage range by changing the underlying surface, and the specific method is to calculate the ratio of the difference Δ between the optimal vegetation coverage S and the current vegetation coverage C to the current vegetation coverage C, and thus calculate the area ratio δ of the underlying surface that needs to be changed.

[0076] One of the implementations of the artificial change of the underlying surface is to first plough the target area of the grassland, and then lay a layer of gravel on the surface of the ploughed furrow to change the underlying surface of the meadow and form a gravel belt. The gravel should be laid as soon as possible after ploughing to avoid excessive evaporation of soil moisture. The size of the gravel should be considered for both precipitation infiltration and prevention of soil moisture evaporation, so the gravel cannot be too large or too small, and the gravel with a particle size of about 5-10 cm is preferred. As shown in Figure 1 The gravel belt is along the contour direction of the meadow, the length of the ploughed furrow is consistent with the length of the grassland in the repair area, and the distance L between adjacent gravel belts is determined according to the set ratio δ:

[0077] L = B / δ

[0078] In the formula, B is the width of the gravel belt, which can be regarded as a constant value because the width of the ploughshare is fixed.

[0079] In the natural environment, the stones on the grassland hinder the growth of the meadow below, but the growth of the meadow around the stones is better than that of the normal meadow, and the soil below the stones is more humid and the water condition is better. Based on this natural phenomenon, the present application changes the underlying surface of the meadow and grassland by first ploughing and then laying gravel, and forms a gravel belt on the surface of the ploughed pit. This can increase the supply of soil water and reduce the consumption of soil water. The present application avoids soil drought by reducing the vegetation cover through ploughing in the early stage, increases the soil infiltration and increases the water storage capacity in the middle stage, and increases the economic benefits of the grassland with the increase of the vegetation cover in the later stage. After changing the underlying surface by using the method, the soil water storage capacity is increased, which can meet the needs of more plant growth. According to the law of natural succession, the number of plants will also increase accordingly, and the economic benefits of the grassland will also increase after the increase of the number of forage grasses, which can alleviate the contradiction between grazing and ecological protection.

[0080] In this embodiment, the vegetation cover of the meadow is directly reduced by ploughing and indirectly reduced by covering the soil after ploughing. Considering that it is not convenient for large agricultural machinery to work on the grassland with a certain slope and it is easy to compact the soil, it is recommended to use a micro tiller or a yak to plough the soil. Yaks are common livestock in the local area, and they are gentle and powerful. They often carry heavy loads during the process of the herders moving the grassland. In the case of insufficient funds, yaks can be used for ploughing.

[0081] In some embodiments, as Figure 2As shown, ploughing time is in early growing season (around May), and the soil is ploughed by triangular plough share. Then a layer of gravel is paved on the surface of the ploughed furrow to form a gravel belt. Firstly, after ploughing, the soil changes from compact to soft, the soil porosity increases, and the proportion of preferential flow in the soil infiltration mode increases significantly, which is beneficial to more precipitation recharge to deep soil. Moreover, the gravel belt is parallel to the contour line, which is beneficial to intercepting slope small runoff, and the runoff is recharged to deep soil along the gravel belt. Secondly, after the gravel belt replaces the meadow, not only the soil water consumption of the meadow is reduced, but also the direct evaporation loss of soil water is reduced. Thirdly, due to the lower specific heat capacity of the surface gravel, it is beneficial to water vapor condensation in clear night, and the soil water recharge is increased. In summary, by changing the underlying surface of the meadow steppe, the soil water recharge is increased, the soil water consumption is reduced, and the soil water storage is increased.

[0082] The above detailed description is further detailed for the purpose, technical solutions and beneficial effects of the embodiments of the present application. It should be understood that the above is only a specific implementation of the embodiments of the present application, and is not used to limit the protection scope of the embodiments of the present application. Any modification, equivalent replacement, improvement, etc. made on the basis of the technical solutions of the embodiments of the present application shall be included in the protection scope of the embodiments of the present application.

Claims

1. A method for ecological restoration of alpine meadows, characterized in that, The optimal vegetation cover range for the target area is assessed, and the optimal vegetation cover range is obtained based on soil moisture and vegetation carrying capacity. Obtain the current vegetation cover of the target area. If the current vegetation cover is not within the optimal vegetation cover range, adjust the vegetation cover to the optimal range by artificially changing the underlying surface.

2. The method for ecological restoration of alpine meadows according to claim 1, characterized in that, The optimal vegetation cover range is set to be such that the vegetation cover does not exceed the soil moisture and vegetation carrying capacity.

3. The method for ecological restoration of alpine meadows according to claim 2, characterized in that, The optimal vegetation cover range is set to be such that the vegetation cover does not exceed 80% of the cover value calculated based on soil moisture and vegetation carrying capacity.

4. The method for ecological restoration of alpine meadows according to claim 2, characterized in that, The optimal vegetation cover range is set such that the vegetation cover does not exceed the level value of the cover in the target area within a set time period.

5. The method for ecological restoration of alpine meadows according to claim 1 or 2, characterized in that, Calculating soil moisture and vegetation carrying capacity includes the following steps: S101. Calculate the effective water storage capacity of the soil: Based on the effective soil depth, the soil profile is divided into K layers at intervals of a mm, and θ layers are stratified. k Let W be the volumetric water content of the k-th soil layer, and W be the soil water storage capacity of the k-th layer. k for: W k =θ k ×a (1) S102. Calculate the average water storage capacity (ASWS) within the effective depth of the soil: In the formula, the unit of the average water storage capacity of the soil layer ASWS is mm; S103. Calculate the minimum value of the average water storage capacity of the soil layer: Record the total average soil water storage (ASWS) measured n times during the entire growing season, arranged from morning to night as W1, W2, ..., W n MVASWS is the minimum average water storage capacity of the soil layer. MVASWS=min(W1,W2…,W n ) (3) S104. Calculate soil moisture and vegetation carrying capacity: The optimal fitting model F(x) was obtained by fitting the minimum value of vegetation cover and corresponding average soil water storage in different plots to MVASWS, with the independent variable being soil water storage W. i The dependent variable is vegetation cover C, that is: C= F(W i ) (4) If W m Substituting the soil water storage corresponding to the wilting point into the above fitting model, the soil moisture-vegetation carrying capacity (SWCCV) is: SWCCV=F(W m ) (5)。 6. The method for ecological restoration of alpine meadows according to claim 1, characterized in that, The method of artificially altering the underlying surface to adjust vegetation cover to the optimal range includes: Calculate the difference Δ between the optimal vegetation cover and the current vegetation cover. If the difference Δ is less than 0, human intervention is required; if the difference Δ is not less than 0, no intervention is needed. Δ=SC (6) In the formula, S is the optimal vegetation cover and C is the current vegetation cover.

7. The method for ecological restoration of alpine meadows according to claim 6, characterized in that, The method of artificially altering the underlying surface to adjust vegetation cover to the optimal range includes: Calculate the ratio of the difference Δ between the optimal vegetation cover S and the current vegetation cover C to the current vegetation cover C, and then calculate the percentage of underlying surface area that needs to be changed: δ=Δ / C (7).

8. The method for ecological restoration of alpine meadows according to claim 7, characterized in that, The artificial alteration of the underlying surface includes: tilling and turning the soil in the target area, and laying gravel on the surface of the furrows to form gravel strips, calculating the distance L between adjacent gravel strips: L=B / δ (8) In the formula, B is the width of the gravel zone. The gravel belt is plowed along the contour lines of the meadow steppe, and the length of the furrows is consistent with the length of the meadow in the target area.

9. The method for ecological restoration of alpine meadows according to claim 8, characterized in that, Use a mini tiller or yaks to plow and turn the soil.

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