Response method for tree age and tending by longibrachia longipedunculata community characteristics and stoichiometry

Abstract

The invention discloses a response method of longibrachia longipedunculata community characteristics and stoichiometry to tree age and tending, and belongs to the field of plant community research, and the method comprises the following steps: S1, researching longibrachia longipedunculata population characteristics; s2, performing stoichiometric research on stems and leaves of the long-handle double-flower trees of different ages; s3, performing stoichiometric research on the long-handle double-flower tree plants and the soil in different tending manners; s4, analyzing indexes; s5, data analysis; and S6, carrying out data visualization processing. The geographical distribution characteristics of the longibrachia longibrachiata community reveal that the longibrachia longibrachiata has a remarkable ancient origin and a wide interrelation in classification. Reasonable application of the phosphatic fertilizer in the growing area of the long-handle double-flower trees is helpful for promoting the growth and development of the long-handle double-flower trees. The tending and intermediate cutting plays a positive role in increasing the height and the ground diameter of the long-handle double-flower tree. The lower-layer tending is beneficial to accumulation of nitrogen, phosphorus and potassium contents of the leaves of the long-handle double-flower trees, and the total phosphorus and total potassium contents of the soil are increased. In order to promote nutrient accumulation of the long-stalk double-flower trees, lower-layer tending can be properly adopted in the future.

Description

Technical Field

[0001] The invention relates to the technical field of plant community research, and in particular to a method for studying the response of Disanthus longipes community characteristics and chemical measurements to tree age and tending. Background Art

[0002] Rare and endangered plants refer to those plant species with limited distribution areas, small populations, relatively rare plants, and very limited geographical distribution, facing extinction or being seriously threatened. Rare and endangered plants often only survive in special habitats or limited places. Once these habitats are destroyed or lost, their survival will face great threats.

[0003] Disanthus longipes is a deciduous shrub of the genus Disanthus in the family Hamamelidaceae. Its distribution range is mainly limited to parts of Zhejiang, Jiangxi and Hunan in China. This distribution area is relatively narrow, and the number of plants in the area is also extremely rare. Therefore, Disanthus longipes is listed as a Class II endangered tree species under national key protection. The twigs of Disanthus longipes are curved, and the leaves are distinctive, with the width significantly greater than the length. The leaves are brightly colored, and the leaves often turn red in autumn. This unique color change makes Disanthus longipes have a high ornamental value and adds rich colors and layers to garden plants. However, Disanthus longipes has a weak sexual reproduction ability and a low seed germination rate under natural conditions, resulting in a relatively narrow distribution area in nature. The remaining number is also extremely rare, and it is often distributed at the edge of the forest, which is very susceptible to human interference or destruction.

[0004] In order to cope with this severe situation, ecologists have been committed to the study of rare and endangered plant communities and have achieved a series of far-reaching research results. These studies mainly focus on the succession process of the community, the flora characteristics of the community, species diversity, and the regeneration status of the population. However, current researchers' research on the long-petaled Disanthus tends to focus on three aspects: reproductive biology, seed physiology, and population ecology. There are few reports on the effects of different tending measures on its soil, branches and leaves, and forest growth. Summary of the invention

[0005] In order to solve the technical problem of the influence of different tending measures on the soil, branches and leaves and tree growth in the above-mentioned prior art, the present invention provides a method for the response of the community characteristics and chemical measurement of Disanthus longipes to tree age and tending.

[0006] To achieve the above technical solution, the present invention provides a method for measuring the response of community characteristics and chemical stoichiometry of Disanthus longipes to tree age and tending, comprising the steps of:

[0007] S1: Study on the population characteristics of Disanthus longipes. Select a typical plant community plot with Disanthus longipes and use the plant community ecology sampling method to conduct field surveys and sampling of the plant resources and habitats of Disanthus longipes communities.

[0008] According to the samples taken, set up standard sample plots and record the specific location, area, altitude, longitude and latitude, and slope direction of the sample plots;

[0009] The tree layer adopts a tree-by-tree survey to record tree species, DBH, tree height and crown width;

[0010] Set up shrub plots around each standard plot, and set up herb plots in the center of each standard plot;

[0011] S2: Study on the stoichiometry of stems and leaves of Disanthus longipes at different ages. From the healthy standard plants, four representative plants were selected from plants of 2, 4, 6 and 8 years old respectively;

[0012] S3: Study on the chemical measurement of different tending of Disanthus longipes and soil, select 5-year-old, 10-year-old and 15-year-old Disanthus longipes with the same site conditions and forest density and small altitude difference to record their tree height and ground diameter; then carry out upper tending, lower tending, full tending and no tending on the trees; use the plant sample collection method in step S2 to investigate the tree height and ground diameter of Disanthus longipes of different ages in the sample plot;

[0013] S4: index analysis, the index analysis includes soil index determination and plant index determination;

[0014] S5: Data analysis, including important values, species diversity, population diameter class structure, and tree height and ground diameter increment;

[0015] S6: Use software Excel, SPSS and Origin to visualize the results obtained in the above steps.

[0016] Furthermore, in step S1, three standard plots of 20m×20m are set; five shrub plots of 5m×5m are set around each standard plot; and five herb plots of 1m×1m are set in the center of each standard plot.

[0017] Furthermore, in step S2, branches of moderate length and uniform size are cut in the four directions of east, south, west and north and in the three positions of top, middle and bottom using high branch shears, and all the collected branches and leaves are collected using the full harvesting method, weighed and transported back to the laboratory for subsequent analysis.

[0018] Furthermore, in step S3, an infrared altimeter is used to measure the tree height with an accuracy of 0.01 cm; a vernier caliper is used to measure the ground diameter with an accuracy of 0.01 cm; and a 5-point method is used to collect soil samples of 0 cm-20 cm.

[0019] Furthermore, the soil index determination includes the determination of soil pH value, soil organic carbon content, soil total nitrogen content, soil total phosphorus content, soil total potassium content, soil available phosphorus content, soil available potassium content and soil alkaline nitrogen content; after the soil index determination is completed, the collected plant samples are dried in an oven at 105°C for 30 minutes, and then the temperature is adjusted to 70°C, and the samples are continued to be dried for 24 hours for treatment, crushed with a crusher and passed through a 0.149mm nylon sieve, and sealed in a plastic bag for storage.

[0020] Furthermore, the plant index determination includes the determination of the total nitrogen content of the plant, the determination of the total phosphorus content of the plant and the determination of the total potassium content of the plant.

[0021] Furthermore, the calculation formula for the importance value of each species is:

[0022] Tree importance value = (relative dominance + relative frequency + relative density) / 3

[0023] Shrub importance value = (relative coverage + relative density + relative frequency) / 3

[0024] Herb importance value = (relative frequency + relative height + relative cover) / 3.

[0025] Further, in step S5, the technical formula for species diversity includes:

[0026] Species richness S:

[0027] S = number of species present in the quadrat

[0028] Shannon-Wiener Index H:

[0029]

[0030] Simpson Index D:

[0031]

[0032] Pielou uniformity index J:

[0033] J = H / lnS.

[0034] Further, in step S5, the population diameter class structure includes: the population diameter class structure analysis adopts a 5-level standing tree division standard, level I: seedlings, breast diameter <8cm; level II: seedlings, 8cm≤breast diameter <16cm; level III: small trees, 16cm≤breast diameter <24cm; level IV: strong trees, 24cm≤breast diameter <32cm; level V: large trees, breast diameter ≥32cm.

[0035] Furthermore, in step S6, the differences between the soil chemical property indicators were analyzed by single-factor analysis of variance; the Duncan multiple comparison test was used in SPSS to test for significant differences, and a correlation analysis was performed on the growth of Disanthus longipes, plant and soil chemical measurement characteristics.

[0036] The beneficial effects of the present invention are:

[0037] (1) The plant composition of the Disanthus longipes community shows a high degree of complexity and diversity. The tropical component accounts for 50.23% of its geographical composition, slightly higher than the temperate component (49.77%). The geographical distribution characteristics of this community reveal the discontinuous distribution of the Old World tropics and East Asia-North America, and reveal that these genera have a significant ancient origin and extensive mutual connection in taxonomy.

[0038] (2) Analysis of the nitrogen-phosphorus stoichiometric ratio of stems and leaves of different ages revealed that phosphorus is the main limiting factor for the growth of D. longipes. Therefore, in areas where D. longipes grows, the rational application of phosphorus fertilizer will help promote the growth and development of the plant.

[0039] (3) Tending thinning has a positive effect on the growth of tree height and ground diameter of Disanthus longipes. Lower layer tending is conducive to the accumulation of nitrogen, phosphorus and potassium content in the leaves of Disanthus longipes, and increases the total phosphorus and total potassium content in the soil. In order to promote nutrient accumulation of Disanthus longipes, lower layer tending can be appropriately adopted in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0041] Figure 1 A flow chart of the method for responding the community characteristics and chemical measurements of Disanthus longipes to tree age and tending provided by the present invention. DETAILED DESCRIPTION

[0042] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0044] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0045] See also Figure 1 As shown, the present invention provides a method for measuring the response of community characteristics and chemical measurements of Disanthus longipes to tree age and tending, characterized in that it includes the steps of:

[0046] S1: Study on the population characteristics of Disanthus longipes. Select a typical plant community plot with Disanthus longipes and use the plant community ecology sampling method to conduct field surveys and sampling of the plant resources and habitats of Disanthus longipes communities.

[0047] According to the samples taken, set up standard sample plots and record the specific location, area, altitude, longitude and latitude, and slope direction of the sample plots;

[0048] The tree layer adopts a tree-by-tree survey to record tree species, DBH, tree height and crown width;

[0049] Set up shrub plots around each standard plot, and set up herb plots in the center of each standard plot;

[0050] S2: Study on the stoichiometry of stems and leaves of Disanthus longipes at different ages. From the healthy standard plants, four representative plants were selected from plants of 2, 4, 6 and 8 years old respectively;

[0051] S3: Study on the chemical measurements of Disanthus longipes with different tending conditions and soil. Select 5-year-old, 10-year-old and 15-year-old Disanthus longipes with the same site conditions and tree density and small altitude difference to record their tree height and ground diameter; then carry out upper tending, lower tending, full tending and no tending on the trees; investigate the tree height and ground diameter of Disanthus longipes of different ages in the sample plots;

[0052] S4: index analysis, the index analysis includes soil index determination and plant index determination;

[0053] S5: Data analysis, including important values, species diversity, population diameter class structure, and tree height and ground diameter increment;

[0054] S6: Use software Excel, SPSS and Origin to visualize the results obtained in the above steps.

[0055] As a preferred method, in step S1, three 20m×20m standard plots are set; five 5m×5m shrub plots are set around each standard plot; and five 1m×1m herb plots are set in the center of each standard plot. That is to say, in the actual operation process, a typical plant community plot with long-stalked disanthus is selected, and the plant community ecology sampling method is used to conduct field surveys and sampling of the plant resources and habitats of the long-stalked disanthus community. Three 20m×20m standard plots are set in the plot according to the actual situation, and the specific location, area, altitude, longitude and latitude, slope and other related factors of the plot are recorded in detail. The tree layer adopts a tree-by-tree survey to record the tree species, breast diameter, tree height, crown width, etc. in detail; five 5m×5m shrub plots and five 1m×1m herb plots are set around and in the center of each standard plot. There are climbing woody or herbaceous plants with vine characteristics in the community. Due to their botanical characteristics, these plants are also classified as shrub layer for analysis.

[0056] As a preferred method, in step S2, high branch shears are used to cut branches of moderate length and uniform size in the four directions of east, south, west and north and the three positions of upper, middle and lower. All branches and leaves collected are collected by the full harvest method, and are weighed and transported back to the laboratory for subsequent analysis. That is to say, in the actual operation process, 4 representative plants are selected from the healthy standard plants according to different ages (2 years, 4 years, 6 years, and 8 years). High branch shears are used to cut branches of moderate length and uniform size in the four directions of east, south, west and north and the three positions of upper, middle and lower. All branches and leaves collected are collected by the full harvest method, and are weighed and transported back to the laboratory for subsequent analysis.

[0057] As a preferred method, in step S3, an infrared altimeter is used to measure the tree height with a measurement accuracy of 0.01 cm; a vernier caliper is used to measure the ground diameter with a measurement accuracy of 0.01 cm; and a 5-point method is used to collect soil samples of 0 cm-20 cm. That is to say, in the actual operation process, artificial tending is carried out, and 5-year-old, 10-year-old and 15-year-old long-stalked double-flowered trees with roughly the same site conditions and forest density and small differences in altitude are selected to record their tree height and ground diameter. Use an infrared altimeter to measure the tree height with a measurement accuracy of 0.01 cm; use a vernier caliper to measure the ground diameter with a measurement accuracy of 0.01 cm.

[0058] Upper layer tending: mainly felling trees, sprouts, large shrubs, vines, etc. that are located in the upper layer of the canopy or provide shade on the sides;

[0059] Bottom layer tending: Remove weeds, vines and bushes around young trees that affect the normal growth of trees, young trees and seedlings through manual removal, while retaining young trees with growth potential and appropriately retaining shrubs between plants.

[0060] Full care: covers both upper care and lower care.

[0061] Uncultivated: The control group without any treatment. The area of ​​the different treatment plots is 600m 2 , and repeat 3 times. Investigate the tree height and ground diameter.

[0062] In the standard sampling area with different tending conditions, ground hole objects and herbaceous plants were removed, and soil samples of 0-20 cm were collected by the 5-point method. Five samples from the same plot were mixed into one sample. A total of 12 samples were obtained from three different tending measures plus three replicates of the control group. The soil samples were brought back to the laboratory in a refrigerator for subsequent processing and analysis. The plant sample collection method in step S2 was used to investigate the tree height and ground diameter of the long-stalked Disanthus chinensis of different ages in the plot.

[0063] As a preferred method, in step S4, the soil index determination includes the determination of soil pH value, soil organic carbon content, soil total nitrogen content, soil total phosphorus content, soil total potassium content, soil available phosphorus content, soil available potassium content and soil alkaline nitrogen content; after the soil index determination is completed, the collected plant samples are dried in a 105°C oven with air blast for 30 minutes, then the temperature is adjusted to 70°C, and the samples are dried for 24 hours, crushed with a pulverizer and passed through a 0.149mm nylon sieve, and sealed in a plastic bag for storage. That is to say, in the actual operation process, the plant index determination includes the determination of plant total nitrogen content, plant total phosphorus content and plant total potassium content.

[0064] That is to say, in actual operation, indicator analysis includes the following contents:

[0065] (1) Determination of soil indicators

[0066] The soil samples were naturally air-dried in a ventilated place without direct sunlight, and stones were picked out and coarse plant and animal residues (dead branches and leaves, roots, insect eggs and other non-soil components) were removed; the soil samples were ground and passed through 2 mm and 0.149 mm nylon sieves respectively.

[0067] Determination of soil pH value: During the determination, weigh 5g of soil sample that has passed through a 2mm sieve and place it in a 50ml plastic bottle, then add 25ml of distilled water to the plastic bottle to prepare a soil solution with a soil-water ratio of 1:5. Oscillate at 20℃~25℃ for 30min (oscillator speed is 150~180 times / min), stop shaking and let it stand to clarify, then use a pH meter to determine the soil pH value (temperature correction of pH value during measurement is automatically completed by the instrument).

[0068] Determination of soil organic carbon content: Potassium dichromate volumetric method was used to determine the soil organic carbon content. During the determination, accurately weigh 0.10g (accurate to 0.0001g) of soil sample that has passed through a 0.149mm sieve and pour it into a dry hard test tube, add 5ml of 0.8mol / L potassium dichromate, shake carefully and add 5ml of concentrated sulfuric acid. Boil at 180℃ for 5min, then cool at room temperature and transfer to a 250ml conical flask, add 3 to 5 drops of o-phenanthroline indicator and mix evenly, and titrate with 0.2mol / L ferrous sulfate standard solution. The solution changes from yellow-green to brown-red, which is the end point. During the titration, a control is set for each group, and digestion and titration are carried out according to the above steps, and the volume of standard solution consumed in this process is recorded.

[0069] Determination of total nitrogen content in soil: First accurately weigh 0.50g of soil sample that has passed through a 0.15mm sieve, place it in a Kelvin flask and add a small amount of deionized water to moisten the soil sample, add 1.1g of catalyst (anhydrous potassium sulfate: copper sulfate pentahydrate: selenium powder = 100:10:1, mass ratio) and 5ml of concentrated sulfuric acid, shake well, and place it on a 300W variable temperature electric furnace for digestion. After digestion, cool it down, transfer the digestion solution to a 50ml colorimetric tube, make up to volume, shake well, filter and store. Then take 1ml of the filtrate to a 50ml colorimetric tube, add 2ml of 0.2mol / L sodium hydroxide solution, 5ml of alkaline phenol and 5ml of sodium hypochlorite, let it stand for 1h, then add 1ml of masking agent to make up to 50ml, shake well, and use a spectrophotometer with a wavelength of 625nm for colorimetry.

[0070] Determination of total phosphorus content in soil: Use colorimetry to determine total phosphorus content in soil. When determining, first weigh 0.2g (accurate to 0.0001g) of terroir sample and carefully place it at the bottom of the crucible, add a small amount of anhydrous ethanol to moisten it, and spread 2g of sodium hydroxide on it. Put the crucible into a high-temperature electric furnace, heat it to 400℃, cut off the power supply and pause for 15min, then continue to heat it to 720℃, keep it for 15min, then take it out and cool it. Add 10ml of water at about 80℃, wash the crucible with water several times, and transfer the washing liquid into the volumetric flask, cool it to volume, filter it and save it, and also do a blank experiment. Take 5 ml of the clarified filtrate and transfer it to a 50 ml colorimetric tube. Add 2 drops of 2,6-dinitrophenol indicator, adjust the pH with dilute HCl solution until the test solution is slightly yellow, add 5 ml of molybdenum antimony anti-colorimetric agent, shake well, add water to make up to 50 ml, and place it for 30 minutes. Compare the color at a wavelength of 650 nm on a spectrophotometer (D-8, Feller Instruments, Nanjing). At the same time, perform a reagent blank test.

[0071] Determination of total potassium content in soil: take 2 ml of the filtrate preserved from the soil total phosphorus experiment into a 50 ml colorimetric tube, add 1 ml of 2 mol / L hydrochloric acid to dissolve, shake to volume, and determine on a flame photometer (FP6431, Shanghai Jingke, Shanghai).

[0072] Determination of soil available phosphorus content: Weigh 5.0g of air-dried soil sample that has passed through a 2mm sieve, place it in a 50ml plastic bottle, add 50ml of hydrochloric acid-ammonium fluoride extractant, and oscillate at 20℃~25℃ for 30min (oscillator speed is 150~180 times / min), and immediately filter it into a wide-mouth bottle using a drying funnel and phosphorus-free filter paper. Pipette 5~10ml of the filtrate (containing 5μgP~25μgP) into a 50ml volumetric flask, add 2 drops of 2,6-dinitrophenol indicator, adjust the pH with dilute HCl solution until the test solution is slightly yellow, add 5ml of molybdenum antimony anti-coloring agent, dilute to 50ml, shake well, and compare colors at a wavelength of 650nm on a spectrophotometer (D-8, Feller Instruments, Nanjing) after 30min. Perform a reagent blank test at the same time.

[0073] Determination of soil available potassium content: weigh 5g (accurate to 0.01g) of air-dried potassium that has passed 2mm in a 100ml plastic tube (or a triangular flask or an oscillating flask), add 50ml of 1mol / L neutral ammonium acetate solution, plug the lid tightly, and filter immediately after oscillation for 30min. The filtrate is placed in a small triangular flask and measured together with a series of potassium standard solutions on a flame photometer (FP6431, Shanghai Jingke, Shanghai), and a curve is drawn on graph paper, and then the corresponding ppm number is found.

[0074] Determination of soil alkaline nitrogen content: Weigh 2.00g of air-dried soil (passed through a 2mm sieve) and place it in the outer chamber of the diffusion dish. Gently rotate the diffusion dish to evenly spread the soil. Take 2ml of boric acid indicator solution and place it in the inner chamber of the diffusion dish. Then apply alkaline glue on the upper edge of the outer chamber of the diffusion dish, cover it with frosted glass, leave a small hole, quickly add 7ml of sodium hydroxide solution, cover it immediately, and then tighten it with a rubber band to fix the frosted glass. Gently shake the diffusion dish to fully mix the alkali solution with the soil. Then put it in a 40℃±1℃ constant temperature box, and take it out after alkaline hydrolysis and diffusion for 24h±0.5h (shake it several times in the middle to increase the diffusion absorption). Titrate the NH3 in the absorption liquid in the inner chamber with a standard sulfuric acid solution. The titration end point is when the solution changes from blue to slightly red. Perform a blank test at the same time as the sample determination to correct the reagent and titration errors.

[0075] The collected plant samples were dried in an oven at 105°C for 30 minutes with forced air, and then the temperature was adjusted to 70°C and dried for 24 hours. The samples were crushed with a grinder and passed through a 0.149 mm nylon sieve, and then sealed in a plastic bag for storage.

[0076] (2) Plant index determination

[0077] Weigh 0.35g (accurate to 0.1000g) of ground and dried plant sample, place it in a 100ml Kjeldahl flask, moisten the sample with water, add 5ml concentrated sulfuric acid, shake gently, place a bent-neck funnel at the mouth of the flask, heat on the circuit until the concentrated sulfuric acid decomposes and emits white smoke and the solution is all brown-black, remove the Kjeldahl flask, cool it slightly, drip 10 drops of 300g / L hydrogen peroxide, and shake it continuously, then heat it to a slight boil, add 5-10 drops of hydrogen peroxide after cooling it slightly, repeat 2 to 3 times until the digestion solution is colorless or cool, then heat it for 5min-10min, and remove excess hydrogen peroxide. Take out the Kjeldahl flask, cool it, pour it into a 50ml volumetric flask, rinse the small funnel with a small amount of water, and wash the washing liquid into the bottle. Filter and save, and also do a blank experiment. The filtrate is used for the determination of N, P, and K elements.

[0078] Determination of total nitrogen content in plants: Pipette 2ml of filtrate and place it in the outer chamber of the diffusion dish, gently rotate the diffusion dish to evenly spread the filtrate. Take 2ml of boric acid indicator solution and place it in the inner chamber of the diffusion dish, then apply alkaline glue on the upper edge of the outer chamber of the diffusion dish, cover it with frosted glass, leave a small hole, quickly add 7ml of sodium hydroxide solution, cover it immediately, and then tighten it with a rubber band to fix the frosted glass, and gently shake the diffusion dish to fully mix the alkali solution with the soil. Then put it in a 40℃±1℃ constant temperature box, and take it out after alkaline hydrolysis and diffusion for 24h±0.5h (shake it several times in the middle to increase the diffusion absorption). Titrate the NH3 in the absorption liquid in the inner chamber with a standard sulfuric acid solution. The titration endpoint is when the solution changes from blue to slightly red. Perform a blank test at the same time as the sample determination to correct the reagent and titration errors.

[0079] Determination of total phosphorus content in plants: pipette 5ml-50ml of the filtrate that has been boiled into a colorimetric tube, add a small amount of distilled water to dilute, add 1 drop of 2,6-dinitrophenol indicator, and then adjust the pH with 2mol / L sodium hydroxide solution until the test solution is slightly yellow, add 5ml of molybdenum antimony anti-colorimetric agent, shake well, add water to make up to 50ml, and place it for 30 minutes before colorimetric analysis at a wavelength of 700nm on a spectrophotometer (D-8, Feller Instruments, Nanjing). At the same time, perform a reagent blank test.

[0080] Determination of total potassium content in plants: pipette 5 ml of the decocted filtrate into a 50 ml colorimetric tube, dilute to volume with water and shake well, and measure on a flame photometer (FP6431, Shanghai Jingke, Shanghai).

[0081] As a preferred embodiment, in step S5, the calculation formula for the importance value of each species is:

[0082] Tree importance value = (relative dominance + relative frequency + relative density) / 3

[0083] Shrub importance value = (relative coverage + relative density + relative frequency) / 3

[0084] Herb importance value = (relative frequency + relative height + relative coverage) / 3

[0085] In the formula: relative density (%) = number of individuals of a certain plant / total number of plant individuals in the sample plot × 100; relative dominance (%) = sum of diameter at breast height of a certain species / sum of diameters at breast height of all species in the sample plot × 100; frequency (%) = number of sample plots where a certain species appears in the community / total number of sample plots × 100, relative frequency (%) = frequency of a certain species / sum of frequencies of all species × 100; relative cover (%) = sum of cover of a certain species / sum of covers of all species in the sample plot × 100; relative height (%) = height of all individuals of a certain species / sum of heights of all individuals of all species in the sample plot × 100.

[0086] As a preferred method, the technical formula for species diversity includes:

[0087] Species richness S:

[0088] S = number of species present in the quadrat

[0089] Shannon-Wiener Index H:

[0090]

[0091] Simpson Index D:

[0092]

[0093] Pielou uniformity index J:

[0094] J=H / lnS

[0095] As a preferred embodiment, in step S5, the population diameter class structure includes: the population diameter class structure analysis adopts a 5-level standing tree division standard, level I: seedlings, breast diameter <8cm; level II: seedlings, 8cm≤breast diameter <16cm; level III: small trees, 16cm≤breast diameter <24cm; level IV: strong trees, 24cm≤breast diameter <32cm; level V: large trees, breast diameter ≥32cm.

[0096] As a preferred embodiment, in step S6, the differences between the soil chemical property indicators are subjected to variance analysis using a single-factor method; the differences are significant using the Duncan multiple comparison test in SPSS, and a correlation analysis is performed on the growth of Disanthus longipes, plant and soil chemical measurement characteristics.

[0097] (4) Increase in tree height and ground diameter: Compare the survey data and calculate the difference between the tree height and ground diameter data measured twice to obtain the increase in each growth indicator.

[0098] Data analysis and chart processing were performed using Excel 2016, SPSS22.0, and Origin 2024 statistical analysis software. The differences between soil chemical property indicators were analyzed by one-way analysis of variance (ANOVA); the Duncan multiple comparison test was used in SPSS22.0 to test for significant differences, and the correlation analysis (Pearson test) was performed on the growth of D. longipes, plant and soil chemical measurement characteristics.

[0099] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0100] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0101] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for characterizing the community and stoichiometry of Disanthus longipes in response to tree age and tending, characterized in that: Includes steps: S1: Study on the population characteristics of Disanthus longipes. Select a typical plant community plot with Disanthus longipes and use the plant community ecology sampling method to conduct field surveys and sampling of the plant resources and habitats of Disanthus longipes communities. According to the samples taken, set up standard sample plots and record the specific location, area, altitude, longitude and latitude, and slope direction of the sample plots; The tree layer adopts a tree-by-tree survey to record tree species, DBH, tree height and crown width; Set up shrub plots around each standard plot, and set up herb plots in the center of each standard plot; S2: Study on the stoichiometry of stems and leaves of Disanthus longipes at different ages. From the healthy standard plants, four representative plants were selected from plants of 2, 4, 6 and 8 years old respectively; S3: Study on the chemical measurement of different tending of Disanthus longipes and soil, select 5-year-old, 10-year-old and 15-year-old Disanthus longipes with the same site conditions and forest density and small altitude difference to record their tree height and ground diameter; then carry out upper tending, lower tending, full tending and no tending on the trees; use the plant sample collection method in step S2 to investigate the tree height and ground diameter of Disanthus longipes of different ages in the sample plot; S4: index analysis, the index analysis includes soil index determination and plant index determination; S5: Data analysis, including important values, species diversity, population diameter class structure, and tree height and ground diameter increment; S6: Use software Excel, SPSS and Origin to visualize the results obtained in the above steps.

2. The method for determining the response of community characteristics and chemical measurements of Disanthus longipes to tree age and tending according to claim 1, characterized in that: In step S1, three standard plots of 20m×20m are set; five shrub plots of 5m×5m are set around each standard plot; and five herb plots of 1m×1m are set in the center of each standard plot.

3. The method for determining the response of community characteristics and chemical measurements of Disanthus longipes to tree age and tending according to claim 1, characterized in that: In step S2, branches of moderate length and uniform size are cut in the four directions of east, south, west and north and in the three positions of top, middle and bottom using high branch shears, and all the collected branches and leaves are collected using the full harvesting method, weighed and transported back to the laboratory for subsequent analysis.

4. The method for determining the response of community characteristics and chemical measurements of Disanthus longipes to tree age and tending according to claim 1, characterized in that: In step S3, the tree height is measured with an infrared altimeter with a measurement accuracy of 0.01 cm; the ground diameter is measured with a vernier caliper with a measurement accuracy of 0.01 cm; and soil samples of 0-20 cm are collected using the 5-point method.

5. The method for determining the response of community characteristics and chemical measurements of Disanthus longipes to tree age and tending according to claim 1, characterized in that: In step S4, the soil index determination includes the determination of soil pH value, soil organic carbon content, soil total nitrogen content, soil total phosphorus content, soil total potassium content, soil available phosphorus content, soil available potassium content and soil alkaline nitrogen content; after the soil index determination is completed, the collected plant samples are dried in an oven at 105°C for 30 minutes, and then the temperature is adjusted to 70°C, and the samples are continued to be dried for 24 hours for treatment, crushed with a crusher and passed through a 0.149mm nylon sieve, and sealed in a plastic bag for storage.

6. The method for determining the response of community characteristics and chemical measurements of Disanthus longipes to tree age and tending according to claim 5, characterized in that: In step S4, the plant index determination includes the determination of the plant total nitrogen content, the determination of the plant total phosphorus content and the determination of the plant total potassium content.

7. The method for determining the response of community characteristics and chemical measurements of Disanthus longipes to tree age and tending according to claim 1, characterized in that: In step S5, the calculation formula for the importance value of each species is: Tree importance value = (relative dominance + relative frequency + relative density) / 3 Shrub importance value = (relative coverage + relative density + relative frequency) / 3 Herb importance value = (relative frequency + relative height + relative cover) / 3.

8. The method for determining the response of community characteristics and chemical measurements of Disanthus longipes to tree age and tending according to claim 7, characterized in that: In step S5, the technical formula for species diversity includes: Species richness S: S = number of species present in the quadrat Shannon-Wiener Index H: Simpson Index D: Pielou uniformity index J: J = H / lnS.

9. The method for determining the response of community characteristics and stoichiometry of Disanthus longipes to tree age and tending according to claim 1, characterized in that: In step S5, the population diameter class structure includes: the population diameter class structure analysis adopts a 5-level standing tree division standard, level I: seedlings, breast diameter <8cm; level II: seedlings, 8cm≤breast diameter <16cm; level III: small trees, 16cm≤breast diameter <24cm; level IV: strong trees, 24cm≤breast diameter <32cm; level V: large trees, breast diameter ≥32cm.

10. The method for determining the response of community characteristics and stoichiometry of Disanthus longipes to tree age and tending according to any one of claims 1 to 9, characterized in that: In step S6, the differences between the soil chemical property indicators were analyzed by single-factor analysis of variance; the Duncan multiple comparison test was used in SPSS to test for significant differences, and the correlation analysis of the growth of Disanthus longipes, plant and soil chemical measurement characteristics was performed at the same time.

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