A method for ex situ plant conservation based on soil ball model

Abstract

The present invention provides a plant ex situ conservation method based on a soil ball model, comprising: determining a plant migration zone that matches a plant migration zone; performing root distribution detection on a target plant that needs to be transplanted in the plant migration zone; establishing a root system configuration model of the target plant according to the root system distribution detection result; determining the soil ball specifications of the target plant according to the root system configuration model of the target plant; excavating the target plant with the soil ball according to the obtained soil ball specifications of the target plant to obtain the target plant with the soil ball; transporting the target plant with the soil ball to the determined plant migration zone; and planting the target plant with the soil ball in the plant migration zone. The present invention provides a plant ex situ conservation method based on a soil ball model, which quantifies a fine determination method of soil ball specifications, and can effectively improve the survival rate of transplanted plants by determining the soil ball specifications of the target plant and assisting other plant ex situ conservation measures.

Description

Technical Field

[0001] The invention belongs to the technical field of plant ex situ conservation, and in particular relates to a plant ex situ conservation method based on a soil ball model. Background Art

[0002] As human development and construction activities continue to advance, many rare and protected plants are affected by engineering construction, and ex situ conservation is an important plant protection measure. Ex situ conservation can move rare and endangered plants and ancient trees that are affected by development and construction activities and cannot be avoided to other places for planting, protection and management. During ex situ conservation, the integrity of the plant root system is the key to affecting the survival rate. Most plants should be transplanted with soil balls to effectively protect the tree root system.

[0003] At present, the ex situ conservation method of plants with soil balls mainly has the following problems:

[0004] The differences in plant root systems and growth areas are not fully considered: the morphology of plant root systems is affected by many factors such as plant species and soil type. The root distribution structure of different plant species varies greatly. Some plants have deep root systems, well-developed taproots, and more lateral roots, but the entire root system is distributed in a deeper soil layer to obtain nutrients and water from the deep soil, such as Masson pine and walnut; some plants have a wider root system, underdeveloped taproots, and lateral roots or adventitious roots extending along the horizontal axis below the ground. The entire root system is distributed in the upper layer of the soil layer to expand the area for obtaining nutrients and water, such as spruce, willow, and locust. Plants in different growth areas often grow according to the soil's water retention capacity and thickness due to different soil types and cover layer thickness.

[0005] The soil ball specifications are not refined enough: Currently, the soil ball specifications are only roughly determined through experience, and the degree of refinement is insufficient. The integrity of the plant root systems obtained is often low, which affects the survival rate of transplanted plants. Summary of the invention

[0006] In view of the defects of the prior art, the present invention provides a plant ex situ conservation method based on a soil ball model, which can effectively solve the above problems.

[0007] The technical solution adopted by the present invention is as follows:

[0008] The present invention provides a method for ex situ plant conservation based on a soil ball model, comprising the following steps:

[0009] Step S1, determining a plant migration zone that matches a plant migration zone;

[0010] Step S2, performing root distribution detection on the target plants to be transplanted in the plant migration zone to obtain root distribution detection results; establishing a root system configuration model of the target plants according to the root system distribution detection results; and determining the soil ball specifications of the target plants according to the root system configuration model of the target plants;

[0011] Step S3, excavating the target plant with the soil ball according to the obtained soil ball specifications of the target plant to obtain the target plant with the soil ball;

[0012] Step S4, transporting the target plant with the soil ball to the plant migration area determined in step S1;

[0013] Step S5, planting the target plant with the soil ball into the plant migration area.

[0014] Preferably, step S2 specifically comprises:

[0015] Step S2.1, select multiple target sample plants in the plant migration area; for each target sample plant, measure the biological indicators, including underground root system parameters and aboveground biological indicators; wherein the underground root system parameters include the average root length L ave , obtained by detecting root distribution through ground penetrating radar; aboveground biological indicators include plant height H, breast diameter DBH and crown area W;

[0016] Step S2.2, for the average root length L ave Pearson correlation analysis was performed on plant height H, DBH and crown area W. The results showed that the average root length L ave and plant height H, average root length L ave and DBH, average root length L ave There were significant correlations between crown area W, plant height H and DBH, and between plant height H and crown area W.

[0017] Step S2.3, for the average root length L ave and plant height H, average root length L ave and DBH, average root length L ave The crown area W, plant height H and DBH, as well as plant height H and crown area W were fitted respectively, and five fitting curves were obtained;

[0018] After analyzing the fitting curves, the following conclusions were obtained:

[0019] Average root length L ave There is an exponential function fitting relationship between L and plant height H: ave =a×H b ; Average root length L ave There is a logarithmic function fitting relationship with plant height H and crown area W: Lave =a×lnH+b×lnW+c; where a, b and c are fitting coefficients respectively; average root length L ave There is a binomial distribution function relationship with DBH;

[0020] Taking the above three relationships into comprehensive consideration, the three-variable nonlinear regression was used to fit the average root length Lave, plant height H, breast diameter DBH and crown area W, and the fitting equation was obtained as follows:

[0021] L ave =a1×ln H+a2×ln W+a3×DBH 2 +a4×DBH+a5

[0022] Among them: a1, a2, a3, a4 are fitting coefficients respectively; a5 is a constant term;

[0023] Step S2.4, establish the constraint conditions: a1≥0, a2≥0, a3≥0, a4≥0, a5≥0; set the initial values ​​of a1, a2, a3, a4 to be 1, and set the initial value of a5 to be 0; perform nonlinear regression analysis on the fitting equation, and when the residual sum of squares reaches the minimum value, obtain the values ​​of the fitting coefficient and the constant term, thereby obtaining the final fitting curve equation;

[0024] Step S2.5, simplifying the root system configuration of each target sample plant into a cone, performing root system distribution detection by ground penetrating radar, and obtaining the root system configuration volume VOL of each target sample plant; and obtaining the ground diameter GD of each target sample plant by ground measurement;

[0025] Pearson correlation analysis was performed on root volume VOL and ground diameter GD, and the results showed that there was a significant correlation between root volume VOL and ground diameter GD.

[0026] The root system volume VOL and the ground diameter GD were fitted with a curve. The results showed that there was a linear relationship between the root system volume VOL and the ground diameter GD: VOL = a6 × GD + a7; where a6 is the fitting coefficient; a7 is the constant term; by analyzing the linear relationship between the root system volume VOL and the ground diameter GD, the final fitting equation between the root system volume VOL and the ground diameter GD was obtained;

[0027] Step S2.6, for each target plant to be transplanted, measure its plant height H, diameter at breast height DBH, crown area W and ground diameter GD respectively;

[0028] According to the fitting equation obtained in step S2.3, the average root length L of the target plant is obtained. ave ; According to the fitting equation obtained in step S2.5, the root configuration volume VOL of the target plant is obtained;

[0029] The average root length L ave 4 times as the soil ball diameter; simplify the root system configuration of the target plant into a cone, and obtain the soil ball depth through the soil ball diameter and the root system configuration volume VOL;

[0030] The soil ball specifications of the target plants are determined accordingly, including the soil ball diameter and soil ball depth.

[0031] Preferably, step S3 specifically comprises:

[0032] Step S3.1, comprehensively determining the transplanting time based on the growth habits of the target plants to be transplanted, the climate characteristics of the plant migration area, and the engineering construction conditions;

[0033] Step S3.2, statistically record the spatial layout and characteristics of all target plants to be transplanted in the plant migration area, including: recording the geographical location coordinates, altitude, tree orientation, ownership, protection level and endangered level of each target plant in the plant migration area;

[0034] Step S3.3, determine the number of target plants that need to be transplanted:

[0035] Step S3.3.1, use the following formula to obtain the minimum population size Pro of the target plant to be protected:

[0036] Pro=L f ×E e ×A m

[0037] in:

[0038] L f , the number of protected plants required by the life form to which the target plant belongs;

[0039] E e , the number of identified ecotypes of target plants, calculated as the number of habitat types;

[0040] A m , the reproductive parameters of the target plants are 1.2 for monoecious plants regardless of self- or cross-pollination, 1.0 for dioecious plants, and 0.8 for apomictic species;

[0041] Step S3.3.2, determining the number of target plants to be transplanted this time according to the determined minimum population number Pro of the target plants to be protected;

[0042] Step S3.4, marking each target plant to be transplanted this time according to the spatial layout and characteristics of the target plants in the plant migration zone recorded in step S3.2 and the number of target plants to be transplanted determined in step S3.3;

[0043] Step S3.5, pruning and digging with soil balls of each marked target plant before digging according to the soil ball specifications of the target plant.

[0044] Preferably, step S3.5 is specifically as follows:

[0045] Step S3.5.1, according to the tree potential balance principle, determine the pruning plan before digging the target plant: Specifically, in order to keep the water and nutrients in the above-ground and underground parts of the target plant balanced, the water balance inside the transplanted plant is maintained mainly by using anti-transpiration agents and light pruning;

[0046] Step S3.5.2, selecting an excavation method based on the growth trend, site conditions, root distribution, and soil conditions of the target plant to be transplanted, and performing excavation with a soil ball;

[0047] The digging methods include: using a large vehicle-mounted tree digger to dig and transplant plants, which is suitable for flat land and large-diameter plants; and using a small handheld tree digger to dig and transplant plants: which is suitable for mountainous areas.

[0048] Preferably, step S4 is specifically:

[0049] Step S4.1, Packaging:

[0050] Use biodegradable rope to tie and fix the soil ball of the target plant with soil ball; then put it into a breathable and water-permeable planting bag;

[0051] Step S4.2, lifting and transportation:

[0052] The plant lifting plan is determined according to the weight, spatial volume, breast diameter, lifting process protection requirements and safety regulations of the target plants with soil balls, and the planting bags containing the target plants with soil balls are lifted one by one onto the air suspension of the transport vehicle; then, the transport vehicles are used to transport them to the plant migration area.

[0053] Preferably, during the transportation of the planting bags containing the target plants with soil balls, an intelligent monitoring system and an intelligent maintenance system are used to perform seedling maintenance on the target plants in the planting bags:

[0054] The intelligent monitoring system monitors the environmental indicators of the planting bag in real time, including soil moisture content, light intensity, temperature and humidity, and feeds back the monitored environmental indicators to the intelligent maintenance system in real time;

[0055] The intelligent maintenance system compares the deviation between the environmental indicators of the planting bag and the environmental indicators of the plant migration area, generates a maintenance strategy, and adjusts the environmental indicators of the planting bag according to the maintenance strategy, so that the deviation between the environmental indicators of the planting bag and the environmental indicators of the plant migration area is less than a set threshold, thereby allowing the target plants in the planting bag to gradually adapt to the growth environment of the plant migration area in advance.

[0056] Preferably, step S5 is specifically:

[0057] Step S5.1, land preparation:

[0058] In the plant migration area, the size of the planting pit and the spacing between transplanted plants are determined according to the breast diameter of the target plant to be transplanted, so as to determine the position of each target plant in the plant migration area; at the corresponding position, a planting pit of corresponding size is dug using an excavation tool, and stones, residual tree roots and broken soil in the pit are removed to make the soil fine, uniform, broken and loose; if the gravel content is high and the soil in the pit is insufficient, foreign soil is used to supplement it;

[0059] Step S5.2, colonization:

[0060] Keep the original north-south direction of the transplanted target plant unchanged, and plant it upright in the planting pit: put the soil ball directly into the planting pit, remove the planting bag, fill the soil in layers and tamp it down, tamping it once for each 30cm thick layer; the backfill soil should be the original soil of the transplanted target plant; the planting depth should be higher than the ground;

[0061] Step S5.3, maintenance:

[0062] Management and protection measures are adopted to manage the target plants, including: setting up a support and protection frame to fix the tree trunk; and adopting a decision-making method for irrigation after plant transplanting based on physical processes to determine the irrigation amount in real time, so as to irrigate the target plants.

[0063] Preferably, step S5.3 specifically includes:

[0064] Step S5.3.1, establish a comprehensive equation for the dynamic change of soil moisture content θ with time t:

[0065]

[0066] in:

[0067] θSoil moisture content, volume fraction, m 3 / m 3 ;

[0068] t time, s;

[0069] z soil depth, m;

[0070] Ks Saturated hydraulic conductivity, cm / s;

[0071] ψ matrix potential, kPa;

[0072] ψ s Reference matrix potential, kPa;

[0073] η exponential factor, dimensionless;

[0074] P(t) precipitation time function, m / s;

[0075] C1 empirical constant, m / s·℃;

[0076] C2 empirical constant, m / s·%RH;

[0077] T a Air temperature, °C;

[0078] T0 reference temperature, °C;

[0079] H sat (T a ) The saturated humidity of air at a given temperature, %RH;

[0080] H a Relative humidity of air, %RH;

[0081] Step S5.3.2, therefore, select the time step, and obtain the soil moisture content θ in real time through step S5.1; if θ<θ target , then the irrigation amount Q = α(θ target -θ)A;

[0082] in:

[0083] θ target Target moisture content, volume fraction, m 3 / m 3 ;

[0084] Q irrigation volume, m 3 ;

[0085] α irrigation coefficient, dimensionless;

[0086] A irrigation area, m 2 ;

[0087] The value of irrigation quantity Q is determined accordingly.

[0088] The plant ex situ conservation method based on the soil ball model provided by the present invention has the following advantages:

[0089] The present invention provides a plant ex situ conservation method based on a soil ball model, which quantifies a method for finely determining soil ball specifications. By determining the soil ball specifications of target plants and assisting other plant ex situ conservation measures, the survival rate of transplanted plants can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 A schematic flow chart of a plant ex situ conservation method based on a soil ball model provided by the present invention;

[0091] Figure 2 A flow chart for preliminary screening of the immigration area provided by the present invention;

[0092] Figure 3 A schematic diagram of root system detection provided by the present invention;

[0093] Figure 4 A volume schematic diagram of the root system configuration provided by the present invention;

[0094] Figure 5 This is a graph showing the effects of environmental factors on growth conditions provided by the present invention. DETAILED DESCRIPTION

[0095] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0096] See also Figure 1 The present invention provides a method for plant ex situ conservation based on a soil ball model, comprising the following steps:

[0097] Step S1, determining a plant migration zone that matches a plant migration zone;

[0098] Step S2, performing root distribution detection on the target plants to be transplanted in the plant migration zone to obtain root distribution detection results; establishing a root system configuration model of the target plants according to the root system distribution detection results; and determining the soil ball specifications of the target plants according to the root system configuration model of the target plants;

[0099] Step S3, excavating the target plant with the soil ball according to the obtained soil ball specifications of the target plant to obtain the target plant with the soil ball;

[0100] Step S4, transporting the target plant with the soil ball to the plant migration area determined in step S1;

[0101] Step S5, planting the target plant with the soil ball into the plant migration area.

[0102] The following is a detailed description of steps S1 to S5:

[0103] Step S1, determining a plant migration zone that matches a plant migration zone;

[0104] When determining the plant immigration area that matches the plant outbound area, three steps may be included: preliminary screening of the plant immigration area, investigation of ecological factors, and matching of the plant immigration area:

[0105] (1) Preliminary screening of plant migration areas

[0106] Taking into account the regional overview, species distribution, habitat conditions, traffic conditions, operating conditions, cost and other factors, a preliminary selection of several proposed relocation areas is made. The regional overview includes geographical location, area, ownership, administrative jurisdiction and other general information. Traffic conditions include route, transport distance, road width, turning radius, bridge and culvert load and other information. Figure 2 Shown is the flowchart for the preliminary screening of the incoming area.

[0107] (2) Ecological factor survey

[0108] Investigate the current status of target plants to be transplanted, habitat conditions of the plant migration areas and the areas to be migrated to, etc.

[0109] The current status of the target plants to be transplanted refers specifically to their growth status, including: ① plant species, distribution area, quantity, stock volume, plant age, plant height, breast diameter or base diameter, crown width, growth status, etc. ② The current status of the main companion and epiphytic plants of the transplanted plants, and insects with a co-evolutionary relationship with the transplanted plants.

[0110] The habitat conditions of the plant migration area and the planned migration area include: ① Topographic and geological data such as altitude, landform, slope and aspect, groundwater level, and geological disasters. ② Meteorological characteristics such as light, temperature, accumulated temperature, humidity, precipitation, wind speed, wind direction, evaporation, and meteorological disasters. ③ Soil data such as soil type, physical and chemical properties, and fertility. ④ Vegetation data such as current vegetation type, plant species, community structure, and distribution characteristics. ⑤ Habitat stability, the number of existing similar populations in the area and the trend of change, and external interference factors and degree.

[0111] (3) Plant migration area matching

[0112] The habitat conditions of the plant migration area were taken as the independent variable, and the growth status of the transplanted plants was taken as the dependent variable. The quantitative relationship between the two was established, and the dominant factors affecting the transplanted plants were extracted. The proposed migration area with the optimal value of the above dominant factors was selected, and it was considered that the habitat suitability of this area was the highest, and it was determined as the migration area.

[0113] The present invention does not limit the specific algorithm for plant migration zone matching. As a preferred embodiment, the present invention provides a method for plant migration zone matching, comprising the following steps:

[0114] Step S1.1, divide the plant migration area into n monitoring areas, collect plant growth indicators in each monitoring area to form a sample; thereby constructing the Y response variable matrix of the plant migration area:

[0115]

[0116] in:

[0117] y ij represents the value of the jth response variable of the i-th sample; where i = 1, 2, ..., n; j = 1, 2, ..., 5;

[0118] y i1 represents the Shannon-Wiener diversity index of the i-th sample;

[0119] y i2 represents the Simpson diversity index of the i-th sample;

[0120] y i3 represents the Pielou uniformity index of the i-th sample;

[0121] y i4 represents the accumulation of the i-th sample;

[0122] y i5 represents the number of target plants in the i-th sample;

[0123] y i1 ,y i2 ,y i3 ,y i4 ,y i5 , forming the plant growth status index of the i-th sample; Y is the centralization matrix.

[0124] Step S1.2, for each monitoring area of ​​the plant migration zone, collect ecological environment indicators to form a sample; thereby constructing the X explanatory variable matrix of the plant migration zone:

[0125]

[0126] in:

[0127] x ik represents the value of the kth explanatory variable of the i-th sample; where i = 1, 2, ..., n; k = 1, 2, ..., 11;

[0128] x i1 represents the pH value of the i-th sample; x i2 represents the moisture content of the i-th sample; x i3 represents the total nitrogen of the i-th sample; x i4represents the total phosphorus of the i-th sample; x i5 represents the total potassium of the i-th sample; x i6 represents the hydrolyzed nitrogen of the i-th sample; x i7 represents the available phosphorus of the ith sample; x i8 represents the available potassium of the ith sample; x i9 represents the organic matter of the i-th sample; x i10 represents the organic carbon of the i-th sample; x i11 represents the gravel content of the ith sample;

[0129] x i1 ,x i2 ,…,x i11 , forming the ecological environment index of the i-th sample; X is the centralization matrix.

[0130] Step S1.3, construct the covariance matrix:

[0131]

[0132] Where: C XY is the covariance matrix between the response variable matrix Y and the explanatory variable matrix X; C XX is the covariance matrix of the explanatory variable matrix X itself;

[0133] Step S1.4, establish the characteristic equation as:

[0134] Where: C YY is the covariance matrix of the response variable matrix Y itself; It is C XX The square root inverse matrix of ; v is the eigenvector; λ is the eigenvalue;

[0135] Step S1.5, solve the characteristic equation established in step S1.4, obtain a set of eigenvalues ​​λ and the eigenvector v corresponding to each eigenvalue λ; use the eigenvector v to linearly combine the explanatory variable matrix X, and use the following formula to obtain the RDA axis:

[0136] RDA=Xv

[0137] Thus, multiple RDA axes are obtained, each of which represents the direction in the explanatory variable matrix X that is most relevant to the response variable matrix Y; Figure 5 As shown, it is a schematic diagram of a specific plurality of RDA axes obtained, that is, the result of explaining the effect of environmental factors on growth conditions.

[0138] The above steps can be implemented in a variety of ways, including but not limited to direct mathematical operations or the use of statistical software.

[0139] Among the RDA axes, two directions that are most relevant to the response variable matrix Y are selected, expressed as: RDA f and RDA g , and its corresponding explanatory variable is x f and x g , is the dominant factor determined;

[0140] Step S1.6: For the n monitoring areas in the plant migration zone, calculate the explanatory variable x f The average and the explanatory variable x g The average

[0141] Determine the proposed immigration area at M; for the proposed immigration area w, w=1,2,…,M, monitor its explanatory variables x respectively f The value of x fw and the explanatory variable x g The value of x gw , using the following formula, ω1, ω2 are weight constants, and the weighted difference Z is obtained w :

[0142]

[0143] Therefore, for the M proposed immigration areas, a total of M weighted differences are obtained; the proposed immigration area with the smallest weighted difference is the final plant immigration area that best matches the plant migration area, thereby determining the plant migration area.

[0144] Step S2, performing root distribution detection on the target plants to be transplanted in the plant migration zone to obtain root distribution detection results; establishing a root system configuration model of the target plants according to the root system distribution detection results; and determining the soil ball specifications of the target plants according to the root system configuration model of the target plants;

[0145] Select several transplanted plants that are easy to measure as sample plants. Use ground penetrating radar to scan the root distribution of sample plants, establish a root morphology model, calculate the root index of each transplanted plant, and determine the specifications of the excavated soil ball based on the root index of each transplanted plant. The specific steps include:

[0146] Step S2.1, select multiple target sample plants in the plant migration area; for each target sample plant, measure the biological indicators, including underground root system parameters and aboveground biological indicators; wherein the underground root system parameters include the average root length L ave , obtained by detecting root distribution through ground penetrating radar; aboveground biological indicators include plant height H, breast diameter DBH and crown area W;

[0147] In this step, when the ground penetrating radar detects the root distribution, it circles the tree several times with the trunk as the center to detect the root distribution of multiple plants with different radii and different depths. Figure 3 The root system detection schematic diagram is shown; the root distribution conditions at different radii and depths are summarized to obtain the basic root system morphology.

[0148] In the present invention, the average root length L ave It is defined as: the arithmetic mean of the length of all the roots of the plant with a diameter of more than 1 cm;

[0149] Then, the quantitative relationship between the above-ground part (branches and trunks) and the underground part (root system) of the plant is established, see steps S2.2 to S2.5.

[0150] Step S2.2, for the average root length L ave Pearson correlation analysis was performed on plant height H, DBH and crown area W. The results showed that the average root length L ave and plant height H, average root length L ave and DBH, average root length L ave There were significant correlations between crown area W, plant height H and DBH, and between plant height H and crown area W.

[0151] Step S2.3, for the average root length L ave and plant height H, average root length L ave and DBH, average root length L ave The crown area W, plant height H and DBH, as well as plant height H and crown area W were fitted respectively, and five fitting curves were obtained;

[0152] After analyzing the fitting curves, the following conclusions were obtained:

[0153] Average root length L ave There is an exponential function fitting relationship between L and plant height H: ave =a×H b ; Average root length L ave There is a logarithmic function fitting relationship with plant height H and crown area W: L ave =a×lnH+b×lnW+c; where a, b and c are fitting coefficients respectively; average root length L ave There is a binomial distribution function relationship with DBH;

[0154] Taking the above three relationships into consideration, the average root length L was calculated by using ternary nonlinear regression. ave , plant height H, breast diameter DBH and crown area W, the fitting equation is:

[0155] L ave=a1×ln H+a2×ln W+a3×DBH 2 +a4×DBH+a5

[0156] Among them: a1, a2, a3, a4 are fitting coefficients respectively; a5 is a constant term;

[0157] Step S2.4, establish the constraint conditions: a1≥0, a2≥0, a3≥0, a4≥0, a5≥0; set the initial values ​​of a1, a2, a3, a4 to be 1, and set the initial value of a5 to be 0; perform nonlinear regression analysis on the fitting equation, and when the residual sum of squares reaches the minimum value, obtain the values ​​of the fitting coefficient and the constant term, thereby obtaining the final fitting curve equation;

[0158] Step S2.5, simplify the root system configuration of each target sample plant into a cone, perform root distribution detection by ground penetrating radar, and obtain the root system configuration volume VOL of each target sample plant; obtain the ground diameter GD of each target sample plant by ground measurement; wherein the root system configuration volume VOL is defined as: the volume of the nearly cone-shaped plant root morphology, such as Figure 4 The figure shows the volume diagram of the root system configuration.

[0159] Pearson correlation analysis was performed on root volume VOL and ground diameter GD, and the results showed that there was a significant correlation between root volume VOL and ground diameter GD.

[0160] The root system volume VOL and the ground diameter GD were fitted with a curve. The results showed that there was a linear relationship between the root system volume VOL and the ground diameter GD: VOL = a6 × GD + a7; where a6 is the fitting coefficient; a7 is the constant term; by analyzing the linear relationship between the root system volume VOL and the ground diameter GD, the final fitting equation between the root system volume VOL and the ground diameter GD was obtained;

[0161] Step S2.6, for each target plant to be transplanted, measure its plant height H, diameter at breast height DBH, crown area W and ground diameter GD respectively;

[0162] According to the fitting equation obtained in step S2.3, the average root length L of the target plant is obtained. ave ; According to the fitting equation obtained in step S2.5, the root configuration volume VOL of the target plant is obtained;

[0163] The average root length L ave 4 times as the soil ball diameter; simplify the root system configuration of the target plant into a cone, and obtain the soil ball depth through the soil ball diameter and the root system configuration volume VOL;

[0164] The soil ball specifications of the target plants are determined accordingly, including the soil ball diameter and soil ball depth.

[0165] Step S3, excavating the target plant with the soil ball according to the obtained soil ball specifications of the target plant to obtain the target plant with the soil ball;

[0166] Step S3 is specifically as follows:

[0167] Step S3.1, comprehensively determining the transplanting time based on factors such as the growth habits of the target plants to be transplanted, the climate characteristics of the plant migration area, and the engineering construction conditions;

[0168] For example, the time of relocation in southern China is from late February to early March, and in northern China it is from early spring when the soil thaws to germination. The time of relocation is also closely related to the type of plant. For deciduous trees, it is during the dormant period, and for coniferous trees, it is during spring, summer (rainy season), and autumn. In summer, it is best to avoid the period of vigorous growth of new shoots.

[0169] Step S3.2, statistically record the spatial layout and characteristics of all target plants to be transplanted in the plant migration area, including: recording the geographical location coordinates, altitude, tree orientation, ownership, protection level and endangered level of each target plant in the plant migration area;

[0170] Step S3.3, determine the number of target plants that need to be transplanted:

[0171] In order to avoid the lack of sufficient genetic representation of the species being conserved, the size of the ex situ conservation population should meet the minimum limit, that is, the minimum population. It is determined by the following methods:

[0172] Step S3.3.1, use the following formula to obtain the minimum population size Pro of the target plant to be protected:

[0173] Pro=L f ×E e ×A m

[0174] in:

[0175] L f , the number of protected plants required by the life form of the target plant; such as 10 to 20 trees, 40 to 50 shrubs, and 100 to 200 herbs;

[0176] E e , the number of ecotypes of the identified target plants (ecotype number), calculated as the number of habitat types;

[0177] A m , the reproductive parameters of the target plants are 1.2 for monoecious plants regardless of self- or cross-pollination, 1.0 for dioecious plants, and 0.8 for apomictic species;

[0178] Step S3.3.2, determining the number of target plants to be transplanted this time according to the determined minimum population number Pro of the target plants to be protected;

[0179] Step S3.4, marking each target plant to be transplanted this time according to the spatial layout and characteristics of the target plants in the plant migration zone recorded in step S3.2 and the number of target plants to be transplanted determined in step S3.3;

[0180] Step S3.5, pruning and digging with soil balls of each marked target plant before digging according to the soil ball specifications of the target plant.

[0181] Step S3.5 is specifically as follows:

[0182] Step S3.5.1, according to the tree potential balance principle, determine the pruning plan before digging the target plant: Specifically, in order to keep the water and nutrients of the above-ground and underground parts of the target plant balanced, thereby ensuring the survival rate of the plant transplantation, it is not advisable to use heavy pruning methods such as cutting branches and cutting trunks. It is advisable to use anti-transpiration agents and light pruning to maintain the water balance inside the transplanted plant;

[0183] Step S3.5.2, selecting an excavation method based on the growth trend, site conditions, root distribution, soil conditions and other factors of the target plant to be transplanted, and performing excavation with a soil ball;

[0184] The digging methods include: large-scale vehicle-mounted tree diggers dig and transplant plants, which are suitable for flat land and large-diameter plants and have high efficiency, but are bulky, have high requirements for the opposite site, are inconvenient to use in mountainous areas, and are extremely expensive; small handheld tree diggers dig and transplant plants: suitable for mountainous areas and portable, but require manual holding of the machine during use, which consumes a lot of physical energy.

[0185] Traditional manual excavation often causes the root soil to be broken and scattered, which in turn affects the survival rate. Therefore, traditional manual excavation methods are not suitable.

[0186] Step S4, transporting the target plant with the soil ball to the plant migration area determined in step S1;

[0187] Step S4 is specifically as follows:

[0188] Step S4.1, Packaging:

[0189] Use biodegradable rope to tie and fix the soil ball of the target plant with soil ball; then, put it into a breathable and water-permeable planting bag.

[0190] Specifically, a reasonable packaging form is selected according to factors such as the growth characteristics of the transplanted plants, the tightness of the soil, the size of the soil ball, and the transportation distance, and the transplanted plants are packaged to facilitate subsequent lifting and transportation. The packaging form should fully consider ensuring that the soil ball is intact and does not scatter. The present invention uses a non-woven bag as a packaging method for planting bags, and uses a soil consolidator when necessary. It is not advisable to use a straw rope wrapping method.

[0191] Step S4.2, lifting and transportation:

[0192] The plant lifting plan is determined according to the weight, spatial volume, breast diameter, lifting process protection requirements and safety regulations of the target plants with soil balls, and the planting bags containing the target plants with soil balls are lifted one by one onto the air suspension of the transport vehicle; then, the transport vehicles are used to transport them to the plant migration area.

[0193] Specifically, the plant transportation plan is determined according to the number, weight, space volume, transportation maintenance requirements and transportation conditions of the transplanted plants, and the transplanted plants are transported from the plant exit area to the plant entry area. Shock absorption measures should be fully considered during the hoisting and transportation process to ensure that the soil ball is intact and does not fall apart during the hoisting and transportation process. The present invention uses an air suspension to support the planting bag.

[0194] In the process of transporting the planting bags containing the target plants with soil balls, an intelligent monitoring system and an intelligent maintenance system are used to perform seedling maintenance on the target plants in the planting bags:

[0195] The intelligent monitoring system monitors the environmental indicators of the planting bag in real time, including soil moisture content, light intensity, temperature and humidity, and feeds back the monitored environmental indicators to the intelligent maintenance system in real time;

[0196] The intelligent maintenance system compares the deviation between the environmental indicators of the planting bag and the environmental indicators of the plant migration area, generates a maintenance strategy, and adjusts the environmental indicators of the planting bag according to the maintenance strategy, so that the deviation between the environmental indicators of the planting bag and the environmental indicators of the plant migration area is less than a set threshold, thereby allowing the target plants in the planting bag to gradually adapt to the growth environment of the plant migration area in advance.

[0197] Step S5, planting the target plant with the soil ball into the plant migration area.

[0198] Step S5 is specifically as follows:

[0199] Step S5.1, land preparation:

[0200] In the plant migration area, the size of the planting pit and the spacing between transplanted plants are determined according to the breast diameter of the target plant to be transplanted, so as to determine the position of each target plant in the plant migration area; at the corresponding position, a planting pit of corresponding size is dug using an excavation tool, and stones, residual tree roots and broken soil in the pit are removed to make the soil fine, uniform, broken and loose; if the gravel content is high and the soil in the pit is insufficient, foreign soil is used to supplement it;

[0201] Specifically, according to the number of transplanted plants and the size of the soil ball, dig the corresponding number and size of the planting pits. The size of the planting pit should be slightly larger than the size of the soil ball. The shape and size of the planting pit are determined according to the distribution of plant roots, the size of the soil ball and soil conditions. The depth of the planting pit is determined according to the ecological characteristics and distribution of the plant roots, as well as the topography, landform, soil texture, groundwater level and drainage conditions of the planting site.

[0202] Land preparation design should consider the overall layout, habitat creation, community construction, terrain preparation and meet the following requirements:

[0203] 1 The overall layout design should follow the planning principle of adapting to local conditions, carry out the overall layout according to the classification of transplanted plant species and their biological characteristics, and reasonably determine the overall plane layout.

[0204] 2 Habitat creation design should be based on the ecological habits of transplanted plants and the characteristics of their natural habitats, and should adopt methods such as terrain shaping, soil improvement and community construction to provide suitable site conditions and succession space for plant growth.

[0205] 3. Community construction and design should follow the principle of imitating nature, comprehensively consider the coordination and stability of interspecies relationships, and reasonably determine the plant species combination, planting scale and density.

[0206] 4. The terrain preparation design should focus on determining the terrain preparation plan in combination with the natural drainage direction of the resettlement area. Local land preparation should determine the appropriate land preparation method based on site conditions and plant species.

[0207] Step S5.2, colonization:

[0208] Place the transplanted plants into the planting pit. Determine the location and orientation of the planting in accordance with the principle of transplanting plants in the original place. Fill the soil and tamp it down.

[0209] Specifically, keep the original north-south direction of the transplanted target plant unchanged, and plant it upright in the planting pit: put the soil ball directly into the planting pit, remove the planting bag, fill the soil in layers and compact it, and compact it once for each layer of 30cm thick; the backfill soil should be the original soil of the transplanted target plant; the planting depth should be higher than the ground;

[0210] Step S5.3, maintenance:

[0211] Management and protection measures are adopted to manage the target plants, including: setting up a support and protection frame to fix the tree trunk; and adopting a decision-making method for irrigation after plant transplanting based on physical processes to determine the irrigation amount in real time, so as to irrigate the target plants.

[0212] Specifically, considering that the root system of plants has been damaged after transplanting, the irrigation timing and amount need to be carefully controlled during the maintenance stage to prevent water shortage or root rot from affecting the survival rate. Therefore, the present invention provides a decision method for irrigation after plant transplanting based on physical processes, and the specific steps are as follows:

[0213] Step S5.3.1, establish a comprehensive equation for the dynamic change of soil moisture content θ with time t:

[0214]

[0215] in:

[0216] θSoil moisture content, volume fraction, m 3 / m 3 ;

[0217] t time, s;

[0218] z soil depth, m;

[0219] K s Saturated hydraulic conductivity, cm / s;

[0220] ψ matrix potential, kPa;

[0221] ψ s Reference matrix potential, kPa;

[0222] η exponential factor, dimensionless;

[0223] P(t) precipitation time function, m / s;

[0224] C1 empirical constant, m / s·℃;

[0225] C2 empirical constant, m / s·%RH;

[0226] T a Air temperature, °C;

[0227] T0 reference temperature, °C;

[0228] H sat (T a ) The saturated humidity of air at a given temperature, %RH;

[0229] H a Relative humidity of air, %RH;

[0230] In the above equation, matrix potential ψ is an important indicator, reflecting the water potential reduction value caused by the attraction of soil matrix to water. It can be measured by negative pressure gauge, pressure membrane instrument, capacitance sensor, etc., or calculated by existing data. Time t can be selected according to the need for precise control. In view of the fact that precipitation P(t) comes from public weather forecasts, the time step should be 3h to 48h.

[0231] Step S5.3.2, decision rule: select the time step, and obtain the soil moisture content θ in real time through step S5.1; if θ<θ target , then the irrigation amount Q = α(θ target -θ)A;

[0232] in:

[0233] θ target Target moisture content, volume fraction, m 3 / m 3 ;

[0234] Q irrigation volume, m 3 ;

[0235] α irrigation coefficient, dimensionless;

[0236] A irrigation area, m 2 ;

[0237] The value of irrigation quantity Q is determined accordingly.

[0238] In practical applications, transplanted plants are managed, maintained and monitored.

[0239] Management and maintenance measures meet the following requirements:

[0240] 1 Maintenance should include post-planting management and later maintenance and management, and it is advisable to adopt maintenance methods such as hanging, supporting, shading, irrigation, pruning, lightning protection, cold and frost protection, pest and disease control, and disaster prevention.

[0241] 2 If rare and endangered plants and ancient trees are involved, records of the management and protection of rare and endangered plants and ancient trees should be kept.

[0242] The monitoring measures shall meet the following requirements:

[0243] 1. According to the ecological habits of transplanted plants and their environmental factors, specific monitoring requirements should be put forward, and the monitoring content, methods, time periods, and frequencies should be clarified, and monitoring records of rare and endangered plants and ancient and famous trees should be carried out. Transplanted rare and endangered plants and ancient and famous trees should be the focus of monitoring, and the monitoring content should include monitoring of transplanted plants and environmental factors.

[0244] 2. Monitoring of transplanted plants usually refers to the monitoring of the number, growth conditions and change trends of transplanted plants; monitoring of environmental factors usually refers to the monitoring of habitat factors, natural interference factors and human interference factors of transplanted plants.

[0245] 3. The monitoring period and frequency should be relatively fixed, and the monitoring frequency should be increased for transplanted plants that are easily disturbed by the surrounding environment. The monitoring agency should regularly analyze and evaluate the monitoring data to understand the changes in transplanted plants and habitats.

[0246] To facilitate understanding of the present invention, the present invention lists the following embodiments. Those skilled in the art should be aware that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0247] The principle of this embodiment is: evaluate the ecological environment indicators of the plant migration area and obtain the dominant factors. According to the suitability of the dominant factors, match and select the plant migration area. Use ground penetrating radar to detect the root distribution of the sample plants, perform model fitting, and establish the quantitative relationship between the above-ground part (ground diameter) and the underground part (root volume) of the plant. Calculate the specifications of the transplanting soil ball for each plant to be transplanted, and use the method of digging and planting with the soil ball to retain the root system to the maximum extent, thereby improving the survival rate.

[0248] To transplant a Cupressaceae plant, follow the steps below.

[0249] 1. Selection of plant migration area

[0250] 1.1. Preliminary screening of plant migration areas

[0251] By retrieving satellite remote sensing images for interpretation, combined with on-site investigation, and analyzing the images within the range, considering that the object of this analysis is Cupressaceae, coniferous forests in the vegetation type map are selected as the main analysis target, with an area greater than 0.5hm 2 The continuous distribution area is considered to be a concentrated distribution area. Remote sensing interpretation shows that there are about 100 concentrated coniferous forests within the range.

[0252] DEM was extracted within the scope, slope maps were made, roads were superimposed, and areas with a slope of less than 45° within 100m on both sides of the road were identified as accessible areas. After screening, the accessible area within the work area was about 1000hm 2

[0253] By superimposing the remote sensing image interpretation results and the accessible area, we can obtain Figure 2 , the coniferous forests in the accessible area were verified, and finally 7 areas to be relocated were preliminarily selected.

[0254] 1.2. Ecological Factor Investigation

[0255] The plant migration area was divided into 11 monitoring areas, and the following ecological environment indicators were collected in each monitoring area: pH, moisture, total nitrogen, total phosphorus, total potassium, hydrolyzed nitrogen, available phosphorus, available potassium, organic matter, organic carbon, and gravel content, thereby constructing the X explanatory variable matrix;

[0256] Diversity indices were collected in each monitoring area, including Shannon-wiener, Simpson and Pielou evenness index, as well as stock volume and target plant number, to construct the Y response variable matrix.

[0257] By using the method of step S1.3 to step S1.5 provided by the present invention, available phosphorus and organic matter are determined as the dominant factors. The explanation rates of available phosphorus and organic matter are 23.3% and 10.2% respectively.

[0258] The above-mentioned dominant factors were matched among the seven proposed migration areas, and one migration area was selected as the final plant migration area.

[0259] 2. Transplantation design

[0260] 2.1 Transplanting time

[0261] According to the biological and ecological characteristics of a certain Cupressaceae plant, the altitude of the migration area and the immigration area (2500m) and the regional climate characteristics, April to May was chosen for transplanting.

[0262] 2.2 Spatial Layout

[0263] Before transplanting, the orientation and position of the plants were marked. To ensure the genetic representativeness of the transplanted plants, about 200 plants were selected for transplanting according to the population size and grouped according to plant height and breast diameter. Plant height H≤1m, 1m<H≤3m、H> The 3m plant ratio is 30:5:1.

[0264] 2.3. Soil ball specifications

[0265] To ensure a high survival rate, the soil ball specifications should retain most of the root system. 26 plants with less obstruction and easy to measure were selected as sample plants. The root system of the sample plants was detected using ground penetrating radar. The soil ball specifications of each plant to be transplanted were calculated using the method of steps S2.1 to S2.6 of the present invention.

[0266] 3. Excavation and transportation

[0267] 3.1. Mining and Packaging

[0268] The transplanting area is located in the mountains, where the soil moisture content is low, the gravel content is high, and the soil ball is easily scattered. A small handheld tree digger is used to dig and transplant plants according to the following steps.

[0269] ① Select plants and define the soil ball area; ② Clear the surface branches and weeds; ③ Dig with a small handheld tree digger; ④ Put the plants and soil balls into non-woven planting bags.

[0270] During the plant excavation process, if the soil ball is partially scattered or falls off as a whole, immediately use methods such as making mud and using polymer moisturizers to deal with it, and then tie it up with nylon ropes, wet straw bags, wet sacks, etc. for rapid transportation.

[0271] The incision of the plant root system should be flat and smooth to facilitate the formation of callus tissue and restore the rooting function of the tissue as soon as possible.

[0272] 3.2. Hoisting and transportation

[0273] The plants packed in the planting bags are loaded one by one. The planting bags of plants with a plant height of H≤1m are loaded manually. The planting bags of plants with a plant height of>1m are hoisted and transported by a 10t crane. When loading and transporting, first load them with a locomotive with a lifting and carrying capacity greater than the total weight of the transplanted plants, and then fix the trunks to prevent damage to the bark and the soil ball. During loading and transportation, pay attention to loading and placing lightly to prevent roots and branches from breaking and soil from being lost at the roots, and prevent other obstacles from destroying and damaging the plants. Each vehicle is allowed to transport about 20 plants, and air bags, straw, etc. are used to tighten between different planting bags, and between the planting bags and the vehicle. The escort personnel carry insulating wooden poles with them to support overhead wires on the way. The steps for unloading plants are the same as hoisting, and loading and unloading boards are used. Strive to be light, slow and stable to protect the plants and the soil ball.

[0274] 4. Colonization monitoring

[0275] 4.1 Land preparation

[0276] During land preparation, disc-shaped planting pits are dug according to the afforestation configuration. Different planting pit sizes and transplanting plant spacings are set for plants with a DBH D≤5cm and DBH D>5cm. If there are native trees and shrubs, bare rock land, steep slopes, etc. in the transplanting area, the transplanted plants are adjusted according to the terrain and the distribution of existing trees and shrubs, and embedded land preparation is adopted to reduce the difficulty of construction and damage to native vegetation.

[0277] Specifications of the planting pit for plants with DBH D>5cm: the diameter of the upper part of the pit should be 40-60cm larger than the diameter of the soil ball of the transplanted plant; the diameter of the lower part of the pit should be 20-30cm larger than the diameter of the soil ball of the transplanted plant, and the depth of the pit should be 20cm larger than the depth of the soil ball of the transplanted plant. The row spacing is 3×3m.

[0278] Specifications of the planting pit for plants with DBH D≤5cm: the diameter of the upper part of the pit should be 20-40cm larger than the diameter of the soil ball of the transplanted plant; the diameter of the lower part of the pit should be 20-30cm larger than the diameter of the soil ball of the transplanted plant, and the depth of the pit should be 10cm larger than the depth of the soil ball of the transplanted plant. The row spacing is 2×2m.

[0279] To ensure the effect and timeliness of land preparation, use excavation tools to prepare the land. It is necessary to remove stones, residual tree roots and broken soil in the pit to make the soil fine, uniform, broken and loose. If the gravel content is high and the soil in the pit is insufficient, foreign soil can be used. Land preparation should be carried out before planting to avoid the loss of plant and soil moisture and to improve the survival rate of transplantation.

[0280] 4.2 Colonization

[0281] When planting, keep the plant's original north-south direction unchanged, and plant it upright. Place the soil ball directly into the planting pit and remove the planting bag and other packaging. Fill the soil in layers and tamp it once for each 30cm thick layer. Try to use the soil from the original habitat of the transplanted plant as the backfill soil. The planting depth is slightly higher than the ground by 5cm.

[0282] 4.3. Maintenance

[0283] Set up a supporting protection frame to fix the tree trunk and prevent it from shaking to ensure the transplanting effect.

[0284] After transplanting, water is applied using the method of step S5.3 of the present invention. Depending on the actual situation of the transplanting area, gravity irrigation, pumping irrigation, watering trucks, etc. are used according to local conditions.

[0285] In spring, dig shallow trenches 2 meters away from the trunk and apply mature fertilizer to promote growth; in autumn, apply phosphorus fertilizer and potassium fertilizer to enhance the plant's ability to survive the winter and resist cold. Loosen the soil and remove weeds in spring and autumn.

[0286] In the first two years after transplanting, strengthen the protection of the tree, use shade, spray water on the leaves or use anti-transpiration agents to prevent burning in summer; in winter, use straw curtains to wrap the tree trunks, set up windbreaks and seal with plastic film to prevent wind and frost, so as to improve the survival rate of transplanting. Transplanted large trees should not be pruned, only dead branches, diseased and insect-infested branches and partially frozen branches can be pruned.

[0287] After the plants are transplanted, their growth conditions and ecological environment indicators are monitored in spring and autumn every year.

[0288] 5. Transplantation assessment

[0289] One month after transplanting, except for the death of the saplings with an initial height of H≤1m, the survival rate of the plants with a height of H>1m was 100%, and the overall survival rate was 99.26%; 18 months after transplanting, some saplings with an initial height of H≤1m died, and the survival rate of the plants with a height of H>1m was still 100%, and the overall survival rate was 97.79%, which was at a relatively high level. The results are shown in Table 1:

[0290] Table 1 Survival of certain Cupressaceae plants after transplantation

[0291]

[0292] It can be seen that the plant ex situ conservation method based on the soil ball model provided by the present invention quantifies the method for finely determining the soil ball specifications. By determining the soil ball specifications of the target plants and assisting other plant ex situ conservation measures, the survival rate of transplanted plants can be effectively improved.

[0293] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A method for ex situ plant conservation based on a soil ball model, characterized in that: The following steps are involved: Step S1, determining a plant migration zone that matches a plant migration zone; Step S2, performing root distribution detection on the target plants to be transplanted in the plant migration zone to obtain root distribution detection results; establishing a root system configuration model of the target plants according to the root system distribution detection results; and determining the soil ball specifications of the target plants according to the root system configuration model of the target plants; Step S3, excavating the target plant with the soil ball according to the obtained soil ball specifications of the target plant to obtain the target plant with the soil ball; Step S3 is specifically as follows: Step S3.1, comprehensively determining the transplanting time based on the growth habits of the target plants to be transplanted, the climate characteristics of the plant migration area, and the engineering construction conditions; Step S3.2, statistically record the spatial layout and characteristics of all target plants to be transplanted in the plant migration area, including: recording the geographical location coordinates, altitude, tree orientation, ownership, protection level and endangered level of each target plant in the plant migration area; Step S3.3, determine the number of target plants that need to be transplanted: Step S3.3.1, use the following formula to obtain the minimum population size Pro of the target plant to be protected: Pro=L f ×E e ×A m in: L f , the number of protected plants required by the life form to which the target plant belongs; E e , the number of identified ecotypes of target plants, calculated as the number of habitat types; A m , the reproductive parameters of the target plants are 1.2 for monoecious plants regardless of self- or cross-pollination, 1.0 for dioecious plants, and 0.8 for apomictic species; Step S3.3.2, determining the number of target plants to be transplanted this time according to the determined minimum population number Pro of the target plants to be protected; Step S3.4, marking each target plant to be transplanted this time according to the spatial layout and characteristics of the target plants in the plant migration zone recorded in step S3.2 and the number of target plants to be transplanted determined in step S3.3; Step S3.5, pruning and digging with soil balls of each marked target plant before digging according to the soil ball specifications of the target plant; Step S4, transporting the target plant with the soil ball to the plant migration area determined in step S1; Step S5, planting the target plant with the soil ball into the plant migration area.

2. The method for ex situ conservation of plants based on a soil ball model according to claim 1, characterized in that: Step S2 is specifically as follows: Step S2.1, select multiple target sample plants in the plant migration zone; for each target sample plant, measure the biological indicators, including underground root system parameters and aboveground biological indicators; wherein the underground root system parameters include the average root length L ave , obtained by detecting root distribution through ground penetrating radar; aboveground biological indicators include plant height H, breast diameter DBH and crown area W; Step S2.2, for the average root length L ave Pearson correlation analysis was performed on plant height H, DBH and crown area W. The results showed that the average root length L ave and plant height H, average root length L ave and DBH, average root length L ave There were significant correlations between crown area W, plant height H and DBH, and between plant height H and crown area W. Step S2.3, for the average root length L ave and plant height H, average root length L ave and DBH, average root length L ave The crown area W, plant height H and DBH, as well as plant height H and crown area W were fitted respectively, and five fitting curves were obtained; After analyzing the fitting curves, the following conclusions were obtained: Average root length L ave There is an exponential function fitting relationship between L and plant height H: ave =a×H b ; Average root length L ave There is a logarithmic function fitting relationship with plant height H and crown area W: L ave =a×lnH+b×lnW+c; where a, b and c are fitting coefficients respectively; average root length L ave There is a binomial distribution function relationship with DBH; Taking the above three relationships into consideration, the average root length L was calculated by using ternary nonlinear regression. ave , plant height H, breast diameter DBH and crown area W, the fitting equation is: <h2 style=";text-align:left;direction:ltr">L<h2 style=";text-align:left;direction:ltr"> ave <h2 style=";text-align:left;direction:ltr"> = a1×lnH+a2×lnW+a3×DBH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +a4×DBH+a5 Among them: a1, a2, a3, a4 are fitting coefficients respectively; a5 is a constant term; Step S2.4, establish the constraint conditions: a1≥0, a2≥0, a3≥0, a4≥0, a5≥0; set the initial values ​​of a1, a2, a3, a4 to be 1, and set the initial value of a5 to be 0; perform nonlinear regression analysis on the fitting equation, and when the residual sum of squares reaches the minimum value, obtain the values ​​of the fitting coefficient and the constant term, thereby obtaining the final fitting curve equation; Step S2.5, simplifying the root system configuration of each target sample plant into a cone, performing root system distribution detection by ground penetrating radar, and obtaining the root system configuration volume VOL of each target sample plant; and obtaining the ground diameter GD of each target sample plant by ground measurement; Pearson correlation analysis was performed on root volume VOL and ground diameter GD, and the results showed that there was a significant correlation between root volume VOL and ground diameter GD. The root system volume VOL and the ground diameter GD were fitted with a curve. The results showed that there was a linear relationship between the root system volume VOL and the ground diameter GD: VOL = a6 × GD + a7; where a6 is the fitting coefficient; a7 is the constant term; by analyzing the linear relationship between the root system volume VOL and the ground diameter GD, the final fitting equation between the root system volume VOL and the ground diameter GD was obtained; Step S2.6, for each target plant to be transplanted, measure its plant height H, diameter at breast height DBH, crown area W and ground diameter GD respectively; According to the fitting equation obtained in step S2.3, the average root length L of the target plant is obtained. ave ; According to the fitting equation obtained in step S2.5, the root configuration volume VOL of the target plant is obtained; The average root length L ave 4 times as the soil ball diameter; simplify the root system configuration of the target plant into a cone, and obtain the soil ball depth through the soil ball diameter and the root system configuration volume VOL; The soil ball specifications of the target plants are determined accordingly, including the soil ball diameter and soil ball depth.

3. The method for ex situ plant conservation based on a soil ball model according to claim 1, characterized in that: Step S3.5 is specifically as follows: Step S3.5.1, according to the tree potential balance principle, determine the pruning plan before digging the target plant: Specifically, in order to keep the water and nutrients in the above-ground and underground parts of the target plant balanced, the water balance inside the transplanted plant is maintained mainly by using anti-transpiration agents and light pruning; Step S3.5.2, selecting an excavation method based on the growth trend, site conditions, root distribution, and soil conditions of the target plant to be transplanted, and performing excavation with a soil ball; The digging methods include: digging and transplanting plants with a large vehicle-mounted tree digger, which is suitable for flat land and large-diameter plants; Small hand-held tree digger for digging and transplanting plants: suitable for mountainous areas.

4. The method for ex situ conservation of plants based on a soil ball model according to claim 1, characterized in that: Step S4 is specifically as follows: Step S4.1, Packaging: Use biodegradable rope to tie and fix the soil ball of the target plant with soil ball; then put it into a breathable and water-permeable planting bag; Step S4.2, lifting and transportation: The plant lifting plan is determined according to the weight, spatial volume, breast diameter, lifting process protection requirements and safety regulations of the target plants with soil balls, and the planting bags containing the target plants with soil balls are lifted one by one onto the air suspension of the transport vehicle; then, the transport vehicles are used to transport them to the plant migration area.

5. The method for ex situ plant conservation based on a soil ball model according to claim 4, characterized in that: During the transportation of the planting bags containing the target plants with soil balls, the intelligent monitoring system and intelligent maintenance system are used to perform seedling maintenance on the target plants in the planting bags: The intelligent monitoring system monitors the environmental indicators of the planting bag in real time, including soil moisture content, light intensity, temperature and humidity, and feeds back the monitored environmental indicators to the intelligent maintenance system in real time; The intelligent maintenance system compares the deviation between the environmental indicators of the planting bag and the environmental indicators of the plant migration area, generates a maintenance strategy, and adjusts the environmental indicators of the planting bag according to the maintenance strategy, so that the deviation between the environmental indicators of the planting bag and the environmental indicators of the plant migration area is less than a set threshold, thereby allowing the target plants in the planting bag to gradually adapt to the growth environment of the plant migration area in advance.

6. The method for ex situ plant conservation based on a soil ball model according to claim 1, characterized in that: Step S5 is specifically as follows: Step S5.1, land preparation: In the plant migration area, the size of the planting pit and the spacing between transplanted plants are determined according to the breast diameter of the target plant to be transplanted, so as to determine the position of each target plant in the plant migration area; at the corresponding position, a planting pit of corresponding size is dug using an excavation tool, and stones, residual tree roots and broken soil in the pit are removed to make the soil fine, uniform, broken and loose; if the gravel content is high and the soil in the pit is insufficient, foreign soil is used to supplement it; Step S5.2, colonization: Keep the original north-south direction of the transplanted target plant unchanged, and plant it upright in the planting pit: put the soil ball directly into the planting pit, remove the planting bag, fill the soil in layers and tamp it down, tamping it once for each 30cm thick layer; the backfill soil should be the original soil of the transplanted target plant; Planting depth is above ground level; Step S5.3, maintenance: Adopt management and protection measures to manage and protect the target plants, including: setting up support and protection frames to fix the tree trunks; And, a decision-making method for post-plant irrigation based on physical processes is used to determine the irrigation amount in real time, so as to irrigate the target plants.

7. The method for ex situ conservation of plants based on a soil ball model according to claim 6, characterized in that: Step S5.3 specifically includes: Step S5.3.1, establish a comprehensive equation for the dynamic change of soil moisture content θ with time t: in: θSoil moisture content, volume fraction, m 3 / m 3 ; t time, s; z soil depth, m; K s Saturated hydraulic conductivity, cm / s; ψ matrix potential, kPa; ψ s Reference matrix potential, kPa; η exponential factor, dimensionless; P(t) precipitation time function, m / s; C1 empirical constant, m / s·℃; C2 empirical constant, m / s·%RH; T a Air temperature, °C; T0 reference temperature, °C; H sat (T a ) The saturated humidity of air at a given temperature, %RH; H a Relative humidity of air, %RH; Step S5.3.2, therefore, select the time step, and obtain the soil moisture content θ in real time through step S5.1; if θ<θ target , then the irrigation amount Q = α(θ target -θ)A; in: θ target Target moisture content, volume fraction, m 3 / m 3 ; Q irrigation volume, m 3 ; α irrigation coefficient, dimensionless; A irrigation area, m 2 ; The value of irrigation quantity Q is determined accordingly.

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