Partitioning method suitable for phenology of plant root systems in alpine grassland

Abstract

The invention discloses a method for dividing plant root system phenology in alpine grassland. The method comprises the steps of test sample plot design, micro root canal installation, plant root system observation, soil layer root system growth dynamic acquisition and calcination, image analysis and root system growth variation calculation. According to the method, on the basis of the monitored change of the root length and the root growth cumulant in the growing season (April to October), the phenology of the root of the alpine meadow is divided into three stages, namely the germination stage, the growth stage, the squaring stage, the flowering stage and the fruiting stage) and the dormancy stage (the withered and yellow stage), which are conventionally observed in combination with the phenology stage (the germination stage), the growth stage (the fruiting stage) and the dormancy stage (the withered and yellow stage) of the overground part of the plant. The method aims at providing a theoretical basis and technical support for research of research on the overground-underground phenological synchronism of a grassland ecosystem by researchers at home and abroad.

Description

Technical Field

[0001] The present invention relates to the technical field of plant root phenological period division, and in particular to a method for dividing the root phenology of alpine grassland plants, and is specifically applied to the impact of climate warming on the root systems of alpine grassland plants. Background Art

[0002] Phenology is the growth and development rhythm formed by plants in response to changes in climatic conditions. The root system is an important organ for plants to absorb and utilize nutrient resources in the soil, especially for alpine meadows where productivity is mainly concentrated in the underground part. At present, most studies on the impact of climate warming and human disturbance on grassland ecosystem phenology are focused on the aboveground part. However, as the main carbon source storage of alpine meadow plants, the root system is not directly observable and is complex and fragile, so the growth dynamics and phenology of the underground root system have received little attention. There are also relatively few studies on underground phenology, especially in the Qinghai-Tibet Plateau, a special alpine region. Therefore, the study of root phenology can more comprehensively grasp the response mechanism of grassland ecosystem productivity to climate warming, provide ideas and references for the study of aboveground-underground phenological synchronization, and provide theoretical support for better prediction and mastering the research on adaptation strategies of alpine grassland vegetation and the restoration and management of degraded grasslands under the background of future global change.

[0003] At present, most studies have only focused on the phenological characteristics of the aboveground parts of plants, while a large part of the resource acquisition of plants in grassland ecosystems is completed underground. It is difficult to fully grasp the changing laws of plant community phenology under climate change and human interference by relying solely on the changing trends of aboveground phenology. Therefore, the study of root phenology has important theoretical and application value for the development of root ecology. Most of the existing studies use the method of dividing underground phenology by root growth rate, and most of them are applied to forest ecosystems, which is not suitable for the study of roots in grassland ecosystems on the Qinghai-Tibet Plateau. Therefore, this patent combines the micro-root window root observation system to develop a method for dividing root phenology.

[0004] Micro-root window technology is a non-destructive, fixed-point direct observation and research method for plant roots. It is the main method for monitoring living roots and dynamic root growth. Its biggest advantage is that it can continuously monitor the changes from birth to death of a single fine root without interfering with the growth process of fine roots. It can also record the growth, production and phenology of fine roots and even root hairs and mycorrhizae. It is an effective method for estimating the underground C distribution and N balance of ecosystems. Combined with the provided root analysis software (micro-root window root observation system), it can quantify root-related data, including root length, area, number of root tips, diameter distribution pattern, number of dead roots and surviving roots, etc. It can also monitor soil moisture conditions according to user needs, so as to study the physiological changes caused by solute migration and water stress in the root area. It is widely used in seedling cultivation, crop growth model research, root pathology analysis, insect behavior ecology and other fields. The BTC-100 root growth dynamic monitoring system is a specific application of this technology.

[0005] In summary, based on the data obtained by tracking root growth using the micro-root window root observation system, a method for dividing the root phenology of alpine grassland plants was introduced. Summary of the invention

[0006] In order to solve the above technical problems, the present invention is based on a micro-root window root observation system, which tracks the data obtained from root growth, based on the changes in the monitored root length and the cumulative amount of root growth during the growing season (April-October), and combined with the conventionally observed phenological periods of the aboveground parts of plants (germination period (greening period), growth period (budding period, flowering period and fruiting period), dormancy period (withering period)). Its purpose is to provide a method for dividing the root phenology of alpine grassland plants.

[0007] The present invention protects a method for dividing the root phenology of plants in alpine grasslands, which specifically comprises the following steps:

[0008] Step 1, experimental plot design: select plant communities and well-growing alpine natural grasslands, arrange the plots, design 5 treatments, 10 replicates for each treatment, and a total of 50 experimental plots. In each experimental plot, use a soil drill and its matching fixing tool to drill a hole with an angle of 45° to the horizontal plane, a depth of 70-75 cm, and a diameter of 7 cm for standby use;

[0009] Step 2, installation of micro root canals: 50 sets of micro root canals with a length of 100 cm and a diameter of 6.4 cm are installed in the above holes for later use;

[0010] Step 3, plant root system observation: plant root system observation is carried out when the space colonization and nutrient level around the root micro-tubes are restored to the level before the disturbance as much as possible; the observation is carried out once a month throughout the year, and the observation frequency is appropriately reduced in winter, and the growth dynamics of the roots in the 0-55cm soil layer throughout the year are obtained at the same time;

[0011] Step 4, dynamic collection of root growth in the soil layer: first, open the tin foil wrapped around the aboveground part of the micro-root tube, remove the black buckle cover on the top of the micro-root tube, wait for 10 to 15 minutes, so that the temperature and humidity in the micro-root tube are fully exchanged with the external environment to achieve a balance between the internal and external environments of the micro-root tube, and then use the equipped detection rod to go deep into the bottom of the micro-root tube to detect whether there is water accumulation, and wipe the water vapor on the inner wall of the micro-root tube to ensure the clarity of the scanned image, align the scanner with the fixed initial position marked for sampling, slide the probe into the bottom of the micro-root tube, and connect the computer to the root scanner software equipped with the CI-600 root observation system (CI-600 Root Scanning System, CID Bio-Science Inc, Camas, WA, USA) for image acquisition, and collect 4 slope-deep images for each micro-root tube;

[0012] Step 5, image analysis: After collecting images through the micro-root window, the root analysis software WinRHZIO Tron MF (CIDBio-Science Inc, Camas, WA, USA) was used to analyze the images, and the root growth characteristic information of root length, root diameter, root surface area and root projection area was obtained, and the root growth change was calculated; images were collected once a month, 5 treatments * 5 repetitions for each treatment * 4 scanned images for each repetition, 100 scanned images can be obtained, and continuous sampling obtained a total of more than 800 root scanned images;

[0013] Step 6, calculation of root growth change:

[0014] (1) Root growth RG

[0015] The root growth amount is the root length of the existing roots and the new roots appearing during the increase interval between two samplings of each tube, and the unit is cm;

[0016] (2) Root growth percentage RGP

[0017] The root growth ratio in each stage was calculated as the percentage (%) of the root growth in that stage to the root growth observed in the entire growing season. The calculation formula is as follows:

[0018]

[0019] Where RGi is the root growth observed at the i-th time; ∑RGi…n is the sum of the root growth observed in all observation stages;

[0020] (3) Cumulative root growth percentage CRGP

[0021]

[0022] Where, CRGPi is the percentage of cumulative root growth up to the i-th observation, and RGPi is the percentage of root growth at the i-th observation;

[0023] The calculated CRGP ranged from 0 to 20% for root germination, from 20 to 80% for root growth, and from 80 to 100% for root dormancy.

[0024] Furthermore, the experimental plot design selected a natural plot with an area of ​​50m×50m, and used a random block design to simulate four gradient warming treatments, which were A red, B yellow, C black and D green in order of the warming amplitude from small to large, with 10 replicates for each treatment; a full random design was used for one control treatment CK, with a total of 10 replicates, and each replicate was surrounded by a PVC pipe with an area of ​​2m 2 The control test plot was set up and protected by fences, and the spacing between the above 50 replications was kept at 2m.

[0025] Optimized, the simulated gradient temperature increase treatment uses conical polyester fiber plastic rings of the same height but different top and bottom diameters buckled on the ground to increase the temperature inside the area; among them, treatment A has a top diameter of 1.6m, a bottom diameter of 2.05m, and a height of 4m; treatment B has a top diameter of 1.3m, a bottom diameter of 1.75m, and a height of 4m; treatment C has a top diameter of 1m, a bottom diameter of 1.45m, and a height of 4m; treatment D has a top diameter of 0.7m, a bottom diameter of 1.15m, and a height of 4m.

[0026] Furthermore, the soil drill is a spiral soil drill with a spiral blade as the drill bit, a total length of 120 cm, and a spiral blade with a diameter of 7 cm; the matching fixing tool is the fixing tool described in the publication number CN217543026U, entitled "A fixing tool for auxiliary installation of micro-root tubes in grassland ecosystems".

[0027] Furthermore, the specific installation of the micro root tube is: slowly put the micro root tube with a sealed bottom tube mouth into the hole, the underground part is 70 to 75 cm, and the tube mouth part exposed on the ground is 25 to 30 cm. It is first wrapped with black tape and then wrapped with a layer of tin foil, and covered with an opaque black buckle cover; then, the drilled soil is filled around the micro root tube, so that the micro root tube is in close contact with the soil, and the photometric test shows that there is basically no influence of light in the micro root tube.

[0028] Furthermore, the micro root tube is made of polycarbonate material.

[0029] Furthermore, in step 3, the observation and sampling times are from November of the first year to October of the second year. According to the Julian calendar, January 1 is the first day, and the other sampling dates are: the 85th day, the 116th day, the 150th day, the 182nd day, the 215th day, the 248th day, the 273rd day, and the 302nd day.

[0030] Furthermore, in step 4, the underground part of the micro-root tube is 70-75 cm, and the root system at a depth of 0-55 cm on the vertical slope of the soil can be observed. The size of each scanned image is 21.59 cm × 19.56 cm, the data accuracy is 600 dpi, and it is saved in jpg format on a portable laptop.

[0031] Compared with the existing technology, the present invention has the following beneficial effects:

[0032] The method of the present invention is based on the monitored changes in root length and the cumulative amount of root growth during the growing season (April-October), and combined with the phenological periods of the aboveground parts of plants (germination period (greening period), growth period (budding period, flowering period and fruiting period), dormancy period (withering period)), the root phenology of the alpine meadow is divided into three stages, namely, germination period, growth period and dormancy period, aiming to provide a theoretical basis and technical support for domestic and foreign scientific researchers to study the synchronization of aboveground and underground phenology of grassland ecosystems. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the design diagram of the sample site of the present invention;

[0034] Figure 2 A growth variation view of the root system is obtained for the present invention;

[0035] Figure 3 RGP is the percentage of root growth at each stage of the present invention i Seasonal variation chart;

[0036] Figure 4 The cumulative root growth percentage CRGP of the present invention is i Seasonal variation chart;

[0037] Figure 5 This is a scene diagram of the installation of the micro-root canal of the present invention. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] 1. Basis for experimental plot design

[0041] (1) Sample site selection

[0042] The research site was selected at the National Field Scientific Observation and Research Station of Alpine Grassland Ecosystem in Haibei Tibetan Autonomous Prefecture, Qinghai Province (Haibei Station for short). An alpine meadow with flat terrain and evenly distributed vegetation was selected as the experimental plot. The experimental station is distributed with typical alpine meadow vegetation types with Kobresia plants as the dominant species, and is representative in the study of root characteristics of alpine meadows.

[0043] Select plant communities and well-growing alpine natural grasslands, arrange sample plots, and prepare

[0044] (2) Sample plot design

[0045] A natural plot with an area of ​​50 m × 50 m was selected, and four simulated gradient warming treatments were designed by random block design. The temperature increase range was from small to large, namely A (red), B (yellow), C (black) and D (green), with 10 replicates for each treatment, for a total of 40 replicates. A control treatment CK was designed by full randomization, for a total of 10 replicates, and each replicate was surrounded by a PVC pipe with an area of ​​2 m 2 The control test plots were protected with wide-meshed solid fences to effectively prevent cattle and sheep from damaging them. The spacing between the 50 replicates was kept at 2m. A hole with a depth of 70-75cm and a diameter of 7cm was drilled in each test plot with an angle of 45° to the horizontal plane using a soil drill and its matching fixing tools (see Appendix for details). Figure 1 ).

[0046] The soil drill is a spiral soil drill with a spiral blade as the drill bit, with a total length of 120 cm and a spiral blade with a diameter of 7 cm; the matching fixing tool is the fixing tool described in the publication number CN217543026U, entitled "A fixing tool for auxiliary installation of micro-root tubes in grassland ecosystems".

[0047] Among them, in order to simulate the gradient warming treatment, conical polyester fiber plastic rings of the same height but different top and bottom diameters were buckled on the ground to increase the temperature inside the area; among them, the top diameter of treatment A was 1.6m, the bottom diameter was 2.05m, and the height was 4m; the top diameter of treatment B was 1.3m, the bottom diameter was 1.75m, and the height was 4m; the top diameter of treatment C was 1m, the bottom diameter was 1.45m, and the height was 4m; the top diameter of treatment D was 0.7m, the bottom diameter was 1.15m, and the height was 4m.

[0048] 2. Installation of micro root canal

[0049] (1) Design basis

[0050] The angle between the root tube and the ground is 45°. Compared with the vertical tube, this installation method avoids the root system from extending downward along the tube wall; compared with the horizontal tube, it can obtain the vertical distribution pattern of the root system, which is the best angle for root observation in the alpine grassland ecosystem. In addition, about 80% of the roots of the alpine grassland plant community are mainly concentrated in the 0-30cm soil layer. The 45° buried root tube length is 70-75cm (5cm error). According to the angle between the root tube and the ground, the depth is converted into the vertical soil layer depth, and the distribution of the alpine meadow root system from 0 to 55cm can be observed, which basically achieves full depth coverage, and the roots distributed in the shallow and deep layers can be fully observed.

[0051] (2) Installation

[0052] 50 sets of 100 cm long and 6.4 cm in diameter polycarbonate micro-root tubes were installed in the above holes, so that the root distribution of the grassland ecosystem could be observed to the greatest extent; the micro-root tubes with sealed bottom tube openings were slowly placed into the holes, with the underground part being 70-75 cm and the tube opening part exposed to the ground being 25-30 cm. They were first wrapped with black tape and then with a layer of tin foil to prevent the light and heat conduction of the micro-root window tubes from affecting the root system, and to reduce the impact of external light and temperature on the environment inside the tubes. At the same time, an opaque black cover was applied to prevent plant dead bodies, dust and water vapor in the air and other debris from entering the tubes; then, the drilled soil was filled around the micro-root tubes to make the micro-root tubes in close contact with the soil. The photometric test showed that there was basically no light influence in the micro-root tubes (see Appendix for details). Figure 5 ).

[0053] 3. Time basis for plant root observation

[0054] (1) Basis of observation time

[0055] Combined with the growth characteristics of alpine meadow plants, root scanning is performed once a month during the growing season, which can basically grasp the dynamic changes of root growth. Since the root system basically stops growing in an environment below 5°C, the observation frequency is appropriately reduced in winter, and continuous observation is performed throughout the year to obtain the growth dynamics of the root system in the 0-55cm soil layer throughout the year.

[0056] (2) Plant root system observation

[0057] When the space colonization and nutrition level around the root micro-tubes are restored to the level before the disturbance as much as possible, the plant root system observation is carried out; the observation is carried out once a month throughout the year, and the observation frequency is appropriately reduced in winter, and the growth dynamics of the roots in the 0-55cm soil layer throughout the year are obtained at the same time;

[0058] The survey period is from November 2018 to October 2019, and the sampling time is November 17, 2018, March 25, 2019, April 24, 2019, May 30, 2019, July 1, 2019, August 3, 2019, September 5, 2019, September 30, 2019, and October 29, 2019. The Julian calendar is used for timekeeping. Taking January 1, 2019 as the first day of the year, the sampling dates in 2019 are recorded as: 85th day (March 25), 116th day (April 24), 150th day (May 30), 182nd day (July 1), 215th day (August 3), 248th day (September 5), 273rd day (September 30), 302nd day (October 29). Among them, the sampling on November 17, 2018 and March 25, 2019 was in winter. Although the samples were taken, the roots basically did not grow, so they are invalid data.

[0059] 4. Dynamic collection and image analysis process of soil root growth

[0060] (1) Dynamic collection of root growth in soil layer

[0061] First, the tin foil wrapped around the aboveground part of the micro-root tube was opened, and the black buckle cover on the top of the micro-root tube was removed. Wait for 10 to 15 minutes to allow the temperature and humidity in the micro-root tube to fully exchange with the external environment and achieve a balance between the internal and external environments of the micro-root tube. Then, the equipped detection rod was used to penetrate into the bottom of the micro-root tube to detect whether there was water accumulation, and the water vapor on the inner wall of the micro-root tube was wiped clean to ensure the clarity of the scanned image. After aligning the scanner with the fixed initial position marked for sampling, the probe was slid into the bottom of the micro-root tube. The computer was connected to the root scanner software equipped with the CI-600 Root Scanning System (CI-600 Root Scanning System, CID Bio-Science Inc, Camas, WA, USA) for image acquisition. Four slope-deep images were collected for each micro-root tube. The underground root tube was 70-75 cm, and the root system at a soil depth of 0-55 cm on the vertical slope of the same amount of soil could be observed. The size of each scanned image was 21.59 cm × 19.56 cm, and the data accuracy was 600 dpi. It was saved in jpg format on a portable laptop.

[0062] (2) Image analysis process

[0063] After the images were collected by the micro-root window, the images scanned by CI-600 were brought back to the laboratory and analyzed using the root analysis software WinRHZIO Tron MF (CID Bio-Science Inc, Camas, WA, USA). The root growth characteristic information of root length, root diameter, root surface area and root projection area was obtained, and the root growth change was calculated (see Appendix for details). Figure 2 ); collect images once a month, 5 treatments * 5 replicates per treatment * 4 scans per replicate, 100 scans can be obtained, and more than 800 root scans can be obtained by continuous sampling.

[0064] 5. Calculation of root growth changes

[0065] (1) Root Growth RG

[0066] The root growth amount is the root length of the existing roots and the new roots appearing during the increase interval between two samplings of each tube, and the unit is cm;

[0067] (2) Root growth percentage RGP i (Root Growth Percentage)

[0068] The root growth ratio in each stage was calculated as the percentage (%) of the root growth in that stage to the root growth observed in the entire growing season. The calculation formula is as follows:

[0069]

[0070] Where RGi is the root growth observed at the i-th time; ∑RGi…n is the sum of the root growth observed in all observation stages;

[0071] (3) Cumulative Root Growth Percentage CRGP

[0072]

[0073] In the formula, CRGPi is the percentage of cumulative root growth observed up to the i-th time, and RGPi is the percentage of root growth observed at the i-th time. The application results are detailed in the attached Figure 3 and attached Figure 4 .

[0074] Table 1 Phenological changes of root growth in the alpine meadow at Haibei Station

[0075]

[0076] Note: i represents the sampling time, which is the month here.

[0077] From the attached Figure 3 and attached Figure 4 As can be seen from Table 1, the change curve of the root system of the alpine meadow at Haibei Station throughout the growing season and the change curve of the cumulative proportion of root growth. Comprehensive observation shows that although the increase in root system from germination to 20% (Julian day 170.33) is not large, the speed is very fast, so this period is divided into the germination period.

[0078] The root growth cumulative proportion enters the growth period from 20% until the cumulative proportion reaches 80% (Julian day 250.91). During this period, the root growth rate is relatively uniform, and the root growth proportion reaches a peak value, so this period is divided into the growth period.

[0079] After the cumulative root growth accounts for 80% (Julian day 250.91), it can be found that the root growth rate begins to slow down and the root growth volume decreases rapidly until the root system stops growing in winter. Therefore, this period is divided into dormancy period.

[0080] In summary, in contrast to the experiment, most studies in the prior art divide the underground phenology into three stages: root germination, vigorous root growth, and root dormancy according to the root growth rate (Radville, 2016). Figure 3 and attached Figure 4), using the root growth amount (based on the length of living roots observed each time) as the basis for division, the 0-20% stage of the cumulative percentage of root growth changing with the month is divided into the germination period, the 20-80% stage is divided into the growth period, and the 80-100% stage is divided into the dormancy period.

[0081] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for dividing the root phenology of alpine grassland plants, characterized in that: The specific steps include: Step 1, experimental plot design: select plant communities and well-growing alpine natural grasslands, arrange the plots, design 5 treatments, 10 replicates for each treatment, and a total of 50 experimental plots. In each experimental plot, use a soil drill and its matching fixing tool to drill a hole with an angle of 45° to the horizontal plane, a depth of 70-75 cm, and a diameter of 7 cm for standby use; Step 2, installation of micro root canals: 50 sets of micro root canals with a length of 100 cm and a diameter of 6.4 cm are installed in the above holes for later use; Step 3, plant root system observation: plant root system observation is carried out when the space colonization and nutrient level around the root micro-tubes are restored to the level before the disturbance as much as possible; the observation is carried out once a month throughout the year, and the observation frequency is appropriately reduced in winter, and the growth dynamics of the roots in the 0-55cm soil layer throughout the year are obtained at the same time; Step 4, dynamic collection of root growth in the soil layer: first, open the tin foil wrapped around the above-ground part of the micro-root tube, remove the black buckle cover on the top of the micro-root tube, wait for 10-15 minutes, so that the temperature and humidity in the micro-root tube are fully exchanged with the external environment to achieve a balance between the internal and external environments of the micro-root tube, and then use the equipped detection rod to go deep into the bottom of the micro-root tube to detect whether there is water accumulation, and wipe the water vapor on the inner wall of the micro-root tube to ensure the clarity of the scanned image, align the scanner with the fixed initial position marked for sampling, slide the probe into the bottom of the micro-root tube, connect the computer to the root scanner software equipped with the CI-600 root observation system for image acquisition, and collect 4 slope-deep images for each micro-root tube; Step 5, image analysis: After the micro-root window collects images, the root system analysis software WinRHZIO Tron MF is used to analyze the images, and the root growth characteristic information of root length, root diameter, root surface area and root projection area is obtained respectively, and the root growth change is calculated; the images are collected once a month, 5 treatments * 5 repetitions for each treatment * 4 scanned images for each repetition, 100 scanned images can be obtained, and continuous sampling obtains a total of more than 800 root system scanned images; Step 6, calculation of root growth change: (1) Root growth RG: The root growth amount is the root length of the existing roots and the new roots appearing during the increase interval between two samplings of each tube, and the unit is cm; (2) Root growth percentage RGP The root growth percentage of each stage was calculated as the percentage of the root growth in that stage to the root growth observed in the entire growing season, and the calculation formula was as follows: Where RGi is the root growth observed at the i-th time; ∑RGi…n is the sum of the root growth observed in all observation stages; (3) Cumulative root growth percentage CRGP Where, CRGPi is the percentage of cumulative root growth up to the i-th observation, and RGPi is the percentage of root growth at the i-th observation; The calculated CRGP ranged from 0 to 20% for root germination, from 20 to 80% for root growth, and from 80 to 100% for root dormancy.

2. The method for dividing the root phenology of alpine grassland plants according to claim 1, characterized in that: The experimental plot design selected a natural plot with an area of ​​50m×50m, and used a random block design to simulate four gradient warming treatments, which were A red, B yellow, C black and D green in order of the warming amplitude from small to large, with 10 replicates for each treatment; a full random design was used for one control treatment CK, with a total of 10 replicates, and each replicate was surrounded by a PVC pipe with an area of ​​2m 2 The control test plot was set up and protected by fences, and the spacing between the above 50 replications was kept at 2m.

3. The method for dividing the root phenology of alpine grassland plants according to claim 2, characterized in that: The simulated gradient temperature increase treatment uses conical polyester fiber plastic rings of the same height but different top and bottom diameters buckled on the ground to increase the temperature inside the area; among them, the top diameter of treatment A is 1.6m, the bottom diameter is 2.05m, and the height is 4m; the top diameter of treatment B is 1.3m, the bottom diameter is 1.75m, and the height is 4m; the top diameter of treatment C is 1m, the bottom diameter is 1.45m, and the height is 4m; the top diameter of treatment D is 0.7m, the bottom diameter is 1.15m, and the height is 4m.

4. The method for dividing the root phenology of alpine grassland plants according to claim 1, characterized in that: The soil drill is a spiral soil drill with a spiral blade as the drill bit, with a total length of 120 cm and a spiral blade with a diameter of 7 cm; the matching fixing tool is the fixing tool described in the publication number CN217543026U, entitled "A fixing tool for auxiliary installation of micro-root tubes in grassland ecosystems".

5. The method for dividing the root phenology of alpine grassland plants according to claim 1, characterized in that: The specific installation of the micro root tube is: slowly put the micro root tube with a sealed bottom tube mouth into the hole, the underground part is 70 to 75 cm, and the tube mouth part exposed above the ground is 25 to 30 cm. It is first wrapped with black tape and then wrapped with a layer of tin foil, and covered with an opaque black buckle cover; then, the drilled soil is filled around the micro root tube, so that the micro root tube is in close contact with the soil, and the photometric test shows that there is basically no influence of light in the micro root tube.

6. The method for dividing the root phenology of alpine grassland plants according to claim 5, characterized in that: The micro root tube is made of polycarbonate material.

7. The method for dividing the root phenology of alpine grassland plants according to claim 1, characterized in that: In step 3, the observation and sampling time is from November of the first year to October of the second year. According to the Julian calendar, January 1 is the first day, and the other sampling dates are: the 85th day, the 116th day, the 150th day, the 182nd day, the 215th day, the 248th day, the 273rd day, and the 302nd day.

8. The method for dividing the root phenology of alpine grassland plants according to claim 1, characterized in that: In step 4, the underground part of the micro-root tube is 70-75 cm, and the root system at a soil layer depth of 0-55 cm on the vertical slope of the equal amount of soil can be observed. The size of each scanned image is 21.59 cm×19.56 cm, the data accuracy is 600 dpi, and it is saved in a portable notebook computer in jpg format.

Images