Method for optimizing water use strategy of populus euphratica clone seedlings based on osmosis

Abstract

The application discloses a Populus euphratica clonal daughter plant water utilization strategy optimization method based on split infiltration wheel irrigation, and relates to the technical field of desert plant ecological restoration, and the specific steps of the optimization method are as follows: a split infiltration wheel irrigation ecological restoration test area is selected, a root breaking area is divided and a root breaking ditch is excavated, and three irrigation modes are adopted for treatment; after three years, a clonal daughter plant-mother plant pair is determined as a research object in September; multiple types of samples are synchronously collected and stored in a low temperature state; samples are treated and indexes are determined; the water contribution proportion is quantified by comparison and a model, the optimal irrigation mode is determined, and the water utilization strategy is optimized; by combining the multi-mode irrigation and the isotope analysis technology, the application accurately analyzes the water source of the Populus euphratica clonal daughter plant, breaks through the traditional experience-driven mode, improves the water resource utilization efficiency, simultaneously, the Bayesian model is used to quantize the water absorption difference of the clonal daughter plants of different ages, a theoretical basis is provided for formulating a differentiated irrigation scheme, and the sustainable restoration of the ecological system is promoted.

Description

Technical Field

[0001] This invention relates to the field of desert plant ecological restoration technology, specifically to an optimization method for water use strategy of Populus euphratica clones based on infiltration and rotational irrigation. Background Technology

[0002] Ecological restoration in arid regions is a key area of ​​global ecological environment governance, with water management for vegetation restoration being a core challenge. Populus euphratica, as a key species in inland river basins, is an ideal choice for ecological restoration due to its clonal reproduction characteristics. However, under the extreme climate conditions of arid regions, the spatial and temporal distribution of surface water and groundwater resources is extremely uneven, making it difficult for traditional irrigation methods to accurately match the water requirements of Populus euphratica clones. In recent years, the development of isotope tracing technology has provided a new tool for analyzing plant water sources. By measuring the stable isotope ratio of xylem water to potential water sources, the contribution of different water sources to plant water absorption can be quantified. Combined with infiltration rotation irrigation technology, how to optimize irrigation patterns to guide Populus euphratica clones to efficiently utilize surface water and reduce dependence on water stored by the mother plant has become a key scientific issue for improving the effectiveness of ecological restoration.

[0003] Traditional irrigation management in ecological restoration has several limitations: First, the irrigation model is too simplistic, often employing a one-size-fits-all approach with fixed intervals and water volumes, failing to consider the differentiated water needs of Populus euphratica clones at different developmental stages. For example, two-year-old seedlings may rely more on surface water, while four-year-old individuals may already be able to utilize deep soil water. However, traditional models cannot dynamically adjust the water supply structure. Second, the analysis of water sources is crude, often inferring indirectly through apparent growth indicators, lacking precise location of the actual water absorption layer of the plant. Although some studies utilize isotope technology, they only qualitatively determine the water absorption layer, failing to quantify the specific contribution ratios of the mother plant, surface water, and soil water at each layer, resulting in a lack of scientific basis for irrigation optimization. Furthermore, traditional methods rarely consider the water relationship between the mother plant and the daughter plant in cloned plants, which may lead to irrigation schemes failing to accurately match the needs of the daughter plant's developmental stage. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an optimization method for water use strategy of Populus euphratica clones based on infiltration rotation irrigation. By setting up a multi-mode irrigation experiment in the ecological restoration experimental area of ​​the lower reaches of the Tarim River, and combining liquid water isotope tracking and Bayesian mixture model, the water contribution ratio of the mother tree, surface water and soil water in each layer to the clones is accurately quantified. This method breaks through the limitations of traditional irrigation relying on experience and extensive water source analysis, reveals the differences in water use of clones of different ages, and screens out the optimal irrigation mode that can reduce dependence on the mother tree and improve surface water utilization, providing a scientific and efficient water resource management solution for ecological restoration in arid areas.

[0005] To solve the above-mentioned technical problems, this invention provides the following technical solution: an optimization method for water use strategy of Populus euphratica clones based on infiltration and rotational irrigation, the specific steps of which are as follows: S100, Site Selection and Pretreatment: A branch irrigation rotational irrigation ecological restoration experimental area was selected, including root-cutting and suckering, overflow seeding, and ecological carrying capacity experimental areas. The root-cutting and suckering experimental area was divided into three regions, D1, D2, and D3, according to the terrain. When the Populus euphratica mother trees had not yet sprouted, 18 root-cutting trenches, 70-90cm deep, 30-50cm wide, and 15-20m long, were dug at a distance of 5-10m from the trees. Then, three irrigation modes, F1, F2, and F3, were used for treatment. The branch irrigation rotational irrigation ecological restoration experimental area is located in Ruoqiang County and Yuli County in the lower reaches of the Tarim River, between the old Tarim River channel and the Qiwenkuoer River, and is a section of the river controlled by the Kunaste Ecological Gate. S200, Research Subjects Determination: In September three years after the irrigation treatment, healthy poplar root-cutting offspring of different ages were selected from different irrigation modes. The clonal root was used to trace the source of the mother plant connected to it, and the clonal offspring-mother plant pair was determined as the research subjects. S300, multi-type sample collection: plant, soil, surface water and groundwater samples are collected simultaneously for the selected research subjects. All samples are sealed in brown containers and stored at low temperature. S400, Sample Processing and Index Determination: Soil samples were dried, and moisture content and water content were calculated. Liquid water was extracted from plant xylem and soil using a LI-2100 fully automated vacuum condensation extraction system. Liquid water isotopes in groundwater, surface water, soil water at various layers, and plant xylem water were measured using an LWIA-912-0008 liquid water isotope analyzer. O and H; S500, Data Analysis and Strategy Optimization: The water-absorbing soil layers of Populus euphratica clones and mother plants are initially determined by direct comparison method and the influence of precipitation is excluded. Then, the Bayesian mixture model is used to quantify the water contribution ratio of the mother plant, surface water and soil water in each layer to the clones. Based on the analysis results, the optimal irrigation mode is determined and the water use strategy is optimized.

[0006] Furthermore, in S100, during the selection and pretreatment of the test site, the three irrigation modes F1, F2, and F3 are as follows: mode F1 has an irrigation interval of 11 days, an irrigation water volume of 6 m³ / 10 m, and an irrigation duration of 2 days; mode F2 has an irrigation interval of 23 days, an irrigation water volume of 7 m³ / 10 m, and an irrigation duration of 3 days; and mode F3 has an irrigation interval of 33 days, an irrigation water volume of 8 m³ / 10 m, and an irrigation duration of 4 days.

[0007] Furthermore, in S200, the research subjects include two-year-old, three-year-old, and four-year-old trees, and the number of cloned daughter-mother pairs is 16. These 16 cloned daughter-mother pairs are grouped under the three irrigation modes F1, F2, and F3 as follows: F1 mode includes two-year-old D1P7S2, D1P3S3; three-year-old D1P2S5; four-year-old D2P10S1, D3P8S1; F2 mode includes two-year-old D3P... 11S, three-year-old D3P11S1, D3P11S2, four-year-old D3P11S8, B1P1S1; F3 model includes two-year-old D1P10S2, D2P13S14, three-year-old D1P10S1, D2P6S1, four-year-old D2P4S7, D2P13S2, where D represents the root-splitting and suckering research area, P is the adult Populus euphratica number, S is the clone seedling number, and B is the adult Populus euphratica not included in the root-splitting and suckering research area.

[0008] Furthermore, in the S300 multi-type sample collection, the plant samples include xylem stems and clonal roots; the xylem stems have a diameter of 0.3-0.5 mm and a length of 3-5 cm, with 5 stems collected from each poplar tree; 3-5 segments of each pair of clonal roots are collected, with each segment having a length of 3-5 cm; and the poplar ecological indicators recorded before sampling include crown width, height, and diameter at breast height, while also recording the distance between the poplar clone daughter plant and the mother plant, i.e., the length of the clonal root.

[0009] Furthermore, in the S300 multi-type sample collection, the soil samples are collected in layers as follows: 20-100cm from the ground surface, with each layer being 20cm apart; 100-350cm from the ground surface, with each layer being 50cm apart, and 3 sample bottles and 1 self-sealing bag soil samples are collected from each layer.

[0010] Furthermore, in the S300, during the collection of multiple types of samples, when sampling surface water, the brown threaded sampling bottle is first cleaned with surface water, and then the sampling bottle is placed in the water and left to stand for 30 seconds; when sampling groundwater, the Bayle tube and sampling bottle are first cleaned with water, the Bayle tube is placed in the well and left to stand for 30 seconds, and then the groundwater in the Bayle tube is transferred into the sampling bottle, and three duplicate samples are collected for both surface water and groundwater.

[0011] Furthermore, in the S500 data analysis and strategy optimization, when using the direct comparison method, the possible soil layers for water absorption by Populus euphratica clones and mother plants are preliminarily determined by combining the precipitation and strong evaporation fractionation effect in the extremely arid area of ​​the lower reaches of the Tarim River, and this is used to rule out the possibility that precipitation is the main source of water absorption.

[0012] Furthermore, in S500, the calculation formula for the Bayesian mixture model in data analysis and strategy optimization is as follows: ,in This indicates the stable isotope ratio of water in the xylem of Populus euphratica clones. It represents the contribution rate of the i-th endmember, i.e., the proportion of a certain water source in the total water absorption of the Populus euphratica clone. It represents the stable isotope ratio of the i-th endmember, referring to the stable isotope ratio of each potential water source. Covariates The effect coefficient, reflecting the degree of influence of environmental variables on the contribution rate of water sources, is calculated through Bayesian statistical inference combined with the MCMC algorithm. The term "covariate" refers to environmental variables that affect the water use of Populus euphratica. It is an observation error. Stable isotope ratios of xylem water in Populus euphratica clones; The method of calculating effect coefficients using Bayesian statistical inference combined with the MCMC algorithm first sets a normal prior distribution with a mean of 0 and a large variance for the effect coefficients. Then, based on the stable isotope ratios of xylem water in Populus euphratica clones, the stable isotope ratios of various potential water sources, and environmental variables affecting water use in Populus euphratica, a likelihood function containing the effect coefficients is constructed. Next, according to Bayes' theorem, the prior distribution and the likelihood function are combined to construct the posterior probability distribution of the effect coefficients. Subsequently, the Markov chain Monte Carlo algorithm is used to sample the posterior probability distribution, generating a large number of effect coefficient samples that conform to the distribution. When the sample size meets the requirements and the sampling process converges, the mean or median of the sample is taken as the optimal estimate of the effect coefficient, and the standard deviation of the sample is used to measure the uncertainty of the estimate.

[0013] Furthermore, in S500, the specific steps of water use strategy optimization in data analysis and strategy optimization are as follows: based on the proportions of water contribution from the mother plant, surface water, and soil water at each layer obtained by the Bayesian mixture model, the changes in the proportions of water contribution from the mother plant, surface water, and deep soil water under different irrigation modes are analyzed and compared. Combined with the water use characteristics of cloned plants of different ages, the irrigation mode that reduces the proportion of water contribution from the mother plant, increases the proportion of water contribution from surface water, and maintains the proportion of water contribution from deep soil water at an effective level is selected and determined as the optimized water use strategy for the cloned plants.

[0014] Compared with existing technologies, this method for optimizing water use strategy for Populus euphratica clones based on infiltration and rotational irrigation has the following advantages: I. This invention, by combining multi-mode irrigation experiments with isotope analysis technology, achieves precise analysis of the water sources of Populus euphratica clones. In traditional ecological restoration, irrigation patterns often rely on experience and lack scientific judgment of the actual water absorption layer of plants, leading to water waste or poor restoration results. This method, through root pruning and sprouting experiments and combined with liquid water isotope tracking technology, quantifies the proportion of water contribution from the mother plant, surface water, and soil water in each layer to the clones. It breaks through the limitations of traditional methods that rely solely on apparent growth indicators, shifting the selection of irrigation patterns from experience-driven to data-driven, improving water resource utilization efficiency, and providing a replicable and quantifiable technical paradigm for ecological restoration in arid areas.

[0015] Second, this invention quantifies the regulatory effect of environmental variables on water sources using a Bayesian mixture model. Traditional studies often focus on single tree ages or the entire community, neglecting the changes in the dependence of clonal plants on water sources at different developmental stages. This method compares the water absorption strategies of two-year-old, three-year-old, and four-year-old clonal plants in groups, and finds that optimizing irrigation patterns can significantly reduce the proportion of water contributed by the mother plant, while improving surface water use efficiency and maintaining an effective supply of deep soil water. This mechanistic discovery provides a theoretical basis for vegetation restoration in arid areas: developing differentiated irrigation schemes for individuals of different ages can avoid excessive consumption of stored water by the mother plant and promote the independent survival ability of clonal plants, ultimately achieving sustainable ecosystem restoration.

[0016] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0018] Figure 1 Flowchart of the method for optimizing water use strategy of Populus euphratica clones based on infiltration rotation irrigation; Figure 2 A schematic diagram of the functional zoning of the ecological restoration experimental area for infiltration irrigation; Figure 3 A schematic diagram showing the location relationship between the cloned poplar plants, the parent plant, and the surrounding water sources; Figure 4 A profile of soil moisture content distribution at different soil depths; Figure 5 A graph showing the contribution ratio of water sources to Populus euphratica clones under different irrigation gradients; Figure 6 A graph showing the contribution ratio of water sources to Populus euphratica clones of different ages; Figure 7 A comparison chart of the proportion of water source utilization by Populus euphratica clones under different irrigation gradients; Figure 8 A comparison chart showing the proportion of water source utilization for cloned poplar trees of different ages. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0020] Example 1: S100, Site selection and pretreatment, such as Figure 1 As shown: The experimental site for this embodiment was also selected in the infiltration and rotational irrigation ecological restoration experimental area located in Ruoqiang County and Yuli County in the lower reaches of the Tarim River. This area is situated between the old Tarim River channel and the Qiwenkuoer River, controlled by the Kunaste ecological gate, and includes a root-cutting and sprouting, overflow seeding, and ecological carrying capacity experimental area. Figure 2 As shown, the area has numerous river networks and ditches, with multiple water sources including shallow soil water, groundwater, and surface water. The water resources exhibit strong spatial heterogeneity, and the poplar trees are concentrated in the area, making it an ideal location for conducting experiments.

[0021] In the root pruning and sprouting experimental area, the terrain was divided into three areas: D1, D2, and D3. From the end of March to the beginning of April 2021, before the mother trees of Populus euphratica sprouted, 18 root pruning trenches were dug 5-10m away from the mother trees in a sunny location, with the soil moisture holding capacity being good and the mother trees growing well. The trenches were 70-90cm deep, 30-50cm wide, and 15-20m long.

[0022] Subsequently, three irrigation modes, F1, F2, and F3, were used for treatment. In mode F1, the irrigation interval was 11 days, the irrigation water volume was 6 m³ / 10 m, and the irrigation duration was 2 days. In mode F2, the irrigation interval was 23 days, the irrigation water volume was 7 m³ / 10 m, and the irrigation duration was 3 days. In mode F3, the irrigation interval was 33 days, the irrigation water volume was 8 m³ / 10 m, and the irrigation duration was 4 days.

[0023] S200, Research Subjects Identified: In September 2024, three years after the irrigation treatment, healthy two-year-old, three-year-old, and four-year-old root-severed poplar plants under three irrigation modes (F1, F2, and F3) were selected. Through clonal root tracing, the study began with clonal poplar plants and continued until their corresponding mother plants were found. Ultimately, 16 pairs of clonal plantlet-mother plantlets were identified as the research subjects. Figure 3 As shown.

[0024] The specific groupings are as follows: F1 mode includes two-year-old D1P7S2 and D1P3S3, three-year-old D1P2S5, and four-year-old D2P10S1 and D3P8S1; F2 mode includes two-year-old D3P11S, three-year-old D3P11S1 and D3P11S2, and four-year-old D3P11S8 and B1P1S1; F3 mode includes two-year-old D1P10S2 and D2P13S14, three-year-old D1P10S1 and D2P6S1, and four-year-old D2P4S7 and D2P13S2. Here, D represents the root-cutting and sprouting research area, P is the adult Populus euphratica number, S is the clone seedling number, and B is the adult Populus euphratica not included in the root-cutting and sprouting research area.

[0025] S300, multi-type sample collection: In September 2024, plant, soil, surface water and groundwater samples were collected simultaneously from 16 selected clone daughter-mother pairs. All samples were sealed in brown containers and stored at low temperature.

[0026] Before sampling, the crown width, height, diameter at breast height (DBH) of the selected Populus euphratica trees were investigated and recorded, as well as the distance between the Populus euphratica clones and the mother trees, i.e., the length of the clone roots.

[0027] Plant samples include xylem stems and clonal roots. For xylem stems, select corky stems with a diameter of 0.3-0.5 mm and a length of 3-5 cm. Collect 5 stems from each Populus euphratica plant. Remove the outer bark and phloem during collection, retaining only the xylem. Collect 3-5 segments of clonal roots from each pair of clonal daughter plants and mother plants, each segment with a length of 3-5 cm. After sampling, quickly place the plant samples into brown glass containers, seal them with cotton, then cover them, and finally seal them with Parafilm. Number and label the samples and store them in an insulated box with ice to avoid evaporation and fractionation affecting the accuracy of stable isotope determination.

[0028] Soil samples were collected at a distance of 50 cm from paired Populus euphratica plants, parallel to the clonal roots connecting the clonal daughter and mother plants, by digging a soil profile to a depth of 4 m. The sampling layers were as follows: 20-100 cm from the ground surface, with each 20 cm layer consisting of 20-40 cm, 40-60 cm, 60-80 cm, and 80-100 cm; and 100-350 cm from the ground surface, with each 50 cm layer consisting of 100-150 cm, 150-200 cm, 200-250 cm, 250-300 cm, and 300-350 cm. Three sample bottles and one self-sealing bag were collected from each layer. The soil samples were sealed and preserved using the same method as the plant samples to avoid mechanical fractionation affecting the test results.

[0029] When collecting surface water and groundwater samples, for surface water sampling, the brown threaded sampling bottle was rinsed with surface water and then placed in the water for 30 seconds. For groundwater sampling, the Bayle tube and sampling bottle were first rinsed with groundwater, the Bayle tube was placed in the well for 30 seconds, and then the groundwater sample in the Bayle tube was transferred into the sampling bottle. Three replicate samples were collected for both surface water and groundwater. The samples were quickly capped and sealed with Parafilm before being placed in an insulated box with ice to avoid mechanical fractionation affecting the experimental results.

[0030] S400, Sample Preparation and Index Determination: After the field collection of samples is completed, the isotope samples are transferred to a refrigerator for storage.

[0031] Soil samples were dried. A suitable amount of soil sample from each bag was placed into three clean aluminum boxes and labeled. The total weight of the aluminum boxes containing the wet soil was weighed using a high-precision electronic balance and recorded as soil sample numbers -Wwet1, -Wwet2, and -Wwet3. The three aluminum boxes were placed in an oven at 105°C and dried for at least 12 hours or until the sample mass was constant. After drying, the aluminum boxes were removed from the oven and placed in a desiccator to cool to room temperature. The total weight of the aluminum boxes and the dry soil was then weighed and recorded as soil sample numbers -Wdry1, -Wdry2, and -Wdry3. The moisture content of each aluminum box soil sample was calculated by the difference between the wet and dry weights. The average of the three replicates of the same soil sample was used to obtain the soil moisture content, and thus the soil water content. Figure 4 As shown.

[0032] Liquid water in plant xylem and soil was extracted using a LI-2100 fully automated vacuum condensation extraction system. Samples were placed in sample vials and tightly sealed with cotton (to prevent sample debris from entering the instrument during extraction). The heating system heated the sample at 130℃ for 2 hours to ensure complete evaporation. The water vapor was captured by a glass tube after passing through a cold well, achieving an extraction efficiency of up to 99%. An LWIA-912-0008 liquid water isotope analyzer was used to determine the concentrations of liquid water in groundwater, surface water, soil water at various layers, and plant xylem water. O and H.

[0033] S500, Data Analysis and Strategy Optimization: Considering the low precipitation and strong evaporation fractionation effect in the extremely arid region of the lower Tarim River, the direct comparison method was first used to preliminarily determine the soil layers in which Populus euphratica clones and mother plants might absorb water, and the influence of precipitation on plant water absorption was excluded.

[0034] The Bayesian mixture model (MixSIAR) is then used to quantify the proportions of water contributions from the mother plant, surface water, and soil water at each layer to the cloned daughter plants. The Bayesian mixture model (MixSIAR) is a stable isotope mixture model based on a Bayesian framework. The calculation formula for the Bayesian mixture model is as follows: ,in This indicates the stable isotope ratio of water in the xylem of Populus euphratica clones. It represents the contribution rate of the i-th endmember, i.e., the proportion of a certain water source in the total water absorption of the Populus euphratica clone. It represents the stable isotope ratio of the i-th endmember, referring to the stable isotope ratio of each potential water source. Covariates The effect coefficient, reflecting the degree of influence of environmental variables on the contribution rate of water sources, is calculated through Bayesian statistical inference combined with the MCMC algorithm. The term "covariate" refers to environmental variables that affect the water use of Populus euphratica. It is an observation error. The stable isotope ratios of xylem water in Populus euphratica clones are given.

[0035] The effect coefficients are calculated using Bayesian statistical inference combined with the MCMC algorithm. First, a normal prior distribution with a mean of 0 and a large variance is set for the effect coefficients. Then, based on the stable isotope ratios of xylem water in Populus euphratica clones, the stable isotope ratios of various potential water sources, and environmental variables affecting water use in Populus euphratica, a likelihood function containing the effect coefficients is constructed. Next, according to Bayes' theorem, the prior distribution is combined with the likelihood function to construct the posterior probability distribution of the effect coefficients. Subsequently, a Markov chain Monte Carlo algorithm is used to sample the posterior probability distribution, generating a large number of effect coefficient samples that conform to this distribution. When the sample size meets the requirements and the sampling process converges, the mean or median of the sample is taken as the optimal estimate of the effect coefficients, and the standard deviation of the sample is used to measure the uncertainty of this estimate.

[0036] The analysis results show that under different irrigation gradients, the mother plant made a significant contribution to the water supply of the root-pruned Populus euphratica seedlings. Under the F1 and F3 irrigation gradients, the average water contribution rate of the mother plant was the largest, at 20.28% and 18.93% respectively, while the average contribution rate of surface water was second, at 18.72% and 18.10% respectively. Under the F2 irrigation gradient, the average water contribution rate of the mother plant was only 0.04% lower at 18.02%, while the average contribution rate of surface water was the largest at 18.06%. Figure 5 As shown, excluding the mother plant and surface water, the contribution of soil water to the water content of the root-severed Populus euphratica seedlings varied with irrigation gradient: Under the F1 irrigation treatment, the average water contribution rate of each soil layer was highest at 60-80cm (16.12%), followed by 20-40cm at 15.72%, and lowest at 40-60cm (13.98%); under the F3 irrigation treatment, the average water contribution rate of the 60-80cm soil layer was highest at 17.27%, followed by 40-60cm at 17.2%, and lowest at 20-40cm at 14.33%; under the F2 irrigation gradient, the average water contribution rate of the 20-40cm layer was highest at 16.74%, followed by 80-100cm at 16.18%, and lowest at 40-60cm at 15.22%.

[0037] Mother trees of different ages all made significant contributions to the water supply of root-pruned Populus euphratica seedlings. The average water source for two-year-old, three-year-old, and four-year-old seedlings was the largest proportion of water from the mother tree, at 19.12%, 18.48%, and 19.52%, respectively. Figure 6 As shown; surface water also makes a significant contribution, with 18.02%, 18.48%, and 18.33% of the water in the two-year, three-year, and four-year plants respectively originating from surface water, such as... Figure 6As shown, apart from the mother plant and surface water, the contribution of soil water in each layer to the water content of the root-cut poplar seedlings varies: the soil water at 40-60cm depth has the largest average contribution rate to the water content of two-year-old poplars at 16.52%, followed by 60-80cm at 15.88%, and the smallest at 80-100cm at 14.98%; for three-year-old poplar seedlings, the soil layer with the largest contribution rate is 60-80cm, with an average contribution rate of 16.50%, followed by 40-60cm at 16.08%, and the smallest at 80-100cm at 14.80%; for four-year-old seedlings, the contribution rate is largest at 60-80cm, followed by 80-100cm at 16.83% and 16.37% respectively, and smallest at 40-60cm at 14.37%.

[0038] Based on the contribution ratios of each water source quantified by the Bayesian mixture model mentioned above, the water use characteristics under different irrigation modes are analyzed and compared, such as... Figure 8 As shown, considering the water use characteristics of clones of different ages, the F2 irrigation model represents a moderate irrigation volume, duration, and interval. Figure 7 As shown, under this mode, the proportion of water contribution from the mother plant to the cloned seedlings decreases, the proportion of water contribution from surface water increases, and the proportion of water contribution from deep soil water remains at an effective level. This enables the root-cut poplar seedlings to gradually shift from relying mainly on water from the mother plant to relying mainly on surface water, reducing the water burden on the mother plant. Therefore, the F2 irrigation mode is determined to be the optimized water use strategy for poplar cloned seedlings, thus completing the optimization of the water use strategy.

[0039] In summary, this embodiment uses Populus euphratica clones in the ecological restoration experimental area of ​​the lower reaches of the Tarim River as the research object. By dividing the root-cutting and sprouting experimental area and setting three irrigation modes (F1, F2, and F3), 16 pairs of cloned offspring-mother plants of different ages were selected. Plant, soil, surface water, and groundwater samples were systematically collected. After processing, soil moisture content and hydrogen and oxygen isotopes of various water sources were measured. The water contribution ratio was analyzed by combining the direct comparison method and the Bayesian mixture model. The results show that under the F2 mode (interval of 23 days, water volume of 7 m³ / 10 m, duration of 3 days), the cloned offspring's dependence on surface water increased, the water contribution of the mother plant decreased, and the contribution of deep soil water remained stable. This is the optimal strategy for water utilization of Populus euphratica cloned offspring and provides a scientific basis for irrigation management of Populus euphratica ecological restoration in arid areas.

[0040] Example 2: S100, Test Site Selection and Pretreatment: The experimental site was selected in the infiltration and rotational irrigation ecological restoration experimental area in Ruoqiang County and Yuli County in the lower reaches of the Tarim River. This area is located between the old Tarim River channel and the Qiwenkuoer River, and belongs to the river section controlled by the Kunaste ecological gate. It includes the root-cutting and sprouting, overflow and floating seed and ecological carrying capacity experimental area. It has a water network composed of river network and ditches, strong spatial heterogeneity of water resources, concentrated distribution of poplar, and is replenished by surface water, soil water and groundwater.

[0041] The root pruning and sprouting experimental area was divided into three regions, D1, D2, and D3, according to the terrain. From the end of March to the beginning of April 2021, before the Populus euphratica mother trees sprouted, 18 root pruning trenches, 70-90cm deep, 30-50cm wide, and 15-20m long, were dug in sunny locations 5-10m away from the mother trees, in areas with good soil moisture retention and good growth of the mother trees. Subsequently, three irrigation modes, F1, F2, and F3, were adopted respectively: F1 with an interval of 11 days, a water volume of 6m³ / 10m, and a duration of 2 days; F2 with an interval of 23 days, a water volume of 7m³ / 10m, and a duration of 3 days; and F3 with an interval of 33 days, a water volume of 8m³ / 10m, and a duration of 4 days.

[0042] S200, Research Subjects Identified: In September 2024, under three irrigation modes, healthy two-year-old, three-year-old, and four-year-old poplar root-cutting progeny plants were selected. Through clonal root tracing, connected mother plants were identified, resulting in 16 pairs of clonal progeny-mother plants. The F1 mode included two-year-old D1P7S2, D1P3S3; three-year-old D1P2S5; and four-year-old D2P10S1, D3P8S1. The F2 mode included two-year-old D3P11S and three-year-old D3P10S1. P11S1, D3P11S2, four-year-old D3P11S8, B1P1S1; F3 model includes two-year-old D1P10S2, D2P13S14, three-year-old D1P10S1, D2P6S1, and four-year-old D2P4S7, D2P13S2, where D represents the root-splitting and suckering research area, P is the adult Populus euphratica number, S is the clone seedling number, and B is the adult Populus euphratica not included in the root-splitting and suckering research area.

[0043] S300, multi-type sample collection: Plant, soil, surface water, and groundwater samples were collected simultaneously. For plant samples, five xylem stems (with the outer bark and phloem removed) with a diameter of 0.3-0.5 mm and a length of 3-5 cm and three to five clonal root segments with a length of 3-5 cm were collected, and the crown width, height, and length of the clonal root were recorded. Soil samples were collected in layers of 20 cm at 20-100 cm depth and in layers of 50 cm at 100-350 cm depth, with three sample bottles and one self-sealing bag for each layer. Surface water samples were collected by rinsing brown bottles and allowing them to stand for 30 seconds before sampling. Groundwater samples were collected using Belle tubes, with three replicates for each sample. All samples were sealed in brown containers and stored at low temperature.

[0044] S400, Sample Preparation and Index Determination: Soil samples were dried at 105℃ to constant weight, and their moisture content and water content were calculated. Liquid water was extracted from plant xylem and soil using a LI-2100 system, and the water content of each source was determined using an LWIA-912-0008 analyzer. O and H.

[0045] S500, Data Analysis and Strategy Optimization: Considering the arid characteristics of the lower reaches of the Tarim River, the direct comparison method was used to eliminate the influence of precipitation and determine the water-absorbing layer. Then, the contribution ratio of each water source was calculated using a Bayesian mixture model. The calculation formula for the Bayesian mixture model is as follows: The results showed that the surface water contribution rate of the F2 mode was 18.06%, which was slightly higher than that of the mother plant (18.02%). The contribution of deep soil water was stable, which could reduce the water dependence of the daughter plants on the mother plant. Therefore, it was determined to be the optimal irrigation mode, and the strategy optimization was completed.

[0046] In summary, this embodiment uses Populus euphratica clones in the ecological restoration experimental area of ​​the lower reaches of the Tarim River as the research object. By dividing the root-cutting and sprouting experimental area and setting three irrigation modes (F1, F2, and F3), 16 pairs of cloned daughter-mother plants of different ages were selected. Plant, soil, surface water, and groundwater samples were systematically collected. After processing, soil moisture content and hydrogen and oxygen isotopes of various water sources were measured. The water contribution ratio was analyzed by combining the direct comparison method and Bayesian mixture model. The results show that under the F2 mode (interval of 23 days, water volume of 7 m³ / 10 m, duration of 3 days), the cloned daughter plants' dependence on surface water increased, the water contribution of the mother plants decreased, and the contribution of deep soil water remained stable. This is the optimal water use strategy and can provide scientific support for irrigation management of Populus euphratica ecological restoration in arid areas.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for optimizing water use strategy of Populus euphratica clones based on infiltration and rotational irrigation, characterized in that, The specific steps of this optimization method are as follows: S100, Site Selection and Pretreatment: The ecological restoration experimental area of ​​infiltration rotation irrigation, which includes root-cutting and suckering, overflow seeding and ecological carrying capacity experimental areas, was selected. The root-cutting and suckering experimental area was divided into three areas, D1, D2 and D3, according to the terrain. When the Populus euphratica mother trees had not sprouted, 18 root-cutting trenches with a depth of 70-90cm, a width of 30-50cm and a length of 15-20m were dug at a distance of 5-10m from them. Then, the three irrigation modes, F1, F2 and F3, were used for treatment respectively. S200, Research Subjects Determination: In September three years after the irrigation treatment, healthy poplar root-cutting offspring of different ages were selected from different irrigation modes. The clonal root was used to trace the source of the mother plant connected to it, and the clonal offspring-mother plant pair was determined as the research subjects. S300, multi-type sample collection: plant, soil, surface water and groundwater samples are collected simultaneously for the selected research subjects. All samples are sealed in brown containers and stored at low temperature. S400, Sample Processing and Index Determination: Soil samples were dried, and moisture content and water content were calculated. Liquid water was extracted from plant xylem and soil using a LI-2100 fully automated vacuum condensation extraction system. Liquid water isotopes in groundwater, surface water, soil water at various layers, and plant xylem water were measured using an LWIA-912-0008 liquid water isotope analyzer. O and H; S500, Data Analysis and Strategy Optimization: The water-absorbing soil layers of Populus euphratica clones and mother plants are initially determined by direct comparison method and the influence of precipitation is excluded. Then, the Bayesian mixture model is used to quantify the water contribution ratio of the mother plant, surface water and soil water in each layer to the clones. Based on the analysis results, the optimal irrigation mode is determined and the water use strategy is optimized. The calculation formula for the Bayesian mixture model is as follows: ,in This indicates the stable isotope ratio of water in the xylem of Populus euphratica clones. It represents the contribution rate of the i-th endmember, i.e., the proportion of a certain water source in the total water absorption of the Populus euphratica clone. It represents the stable isotope ratio of the i-th endmember, referring to the stable isotope ratio of each potential water source. Covariates The effect coefficient, reflecting the degree of influence of environmental variables on the contribution rate of water sources, is calculated through Bayesian statistical inference combined with the MCMC algorithm. The term "covariate" refers to environmental variables that affect the water use of Populus euphratica. It is an observation error. Stable isotope ratios of xylem water in Populus euphratica clones; The specific steps for optimizing the water use strategy are as follows: Based on the proportions of water contribution from the mother plant, surface water, and soil water at each layer to the Populus euphratica clone progeny obtained by the Bayesian mixture model, analyze and compare the changing characteristics of the proportions of water contribution from the mother plant, surface water, and deep soil water under different irrigation modes. Combined with the water use characteristics of clone progeny at different ages, select the irrigation mode that reduces the proportion of water contribution from the mother plant, increases the proportion of water contribution from surface water, and maintains the proportion of water contribution from deep soil water at an effective level, and determine it as the optimized water use strategy for Populus euphratica clone progeny.

2. The method for optimizing water use strategy of Populus euphratica clones based on infiltration rotational irrigation according to claim 1, characterized in that, In S100, during the selection and pretreatment of the experimental site, the three irrigation modes F1, F2, and F3 are as follows: F1 mode has an irrigation interval of 11 days, an irrigation water volume of 6 m³ / 10 m, and an irrigation duration of 2 days; F2 mode has an irrigation interval of 23 days, an irrigation water volume of 7 m³ / 10 m, and an irrigation duration of 3 days; and F3 mode has an irrigation interval of 33 days, an irrigation water volume of 8 m³ / 10 m, and an irrigation duration of 4 days.

3. The method for optimizing water use strategy of Populus euphratica clones based on infiltration rotational irrigation according to claim 1, characterized in that, In the S200 study, the different tree ages included two-year-old, three-year-old, and four-year-old trees, and the number of cloned daughter-mother pairs was 16.

4. The method for optimizing water use strategy of Populus euphratica clones based on infiltration rotation irrigation according to claim 1, characterized in that, In the S300 sampling process, plant samples include xylem stems and clonal roots. The xylem stems are 0.3-0.5 mm in diameter and 3-5 cm in length, with 5 stems collected from each poplar tree. For each pair of clonal roots, 3-5 segments are collected, each segment being 3-5 cm in length. The ecological indicators of the poplar tree recorded before sampling include crown width, height, and diameter at breast height (DBH). The distance between the clonal daughter tree and the mother tree, i.e., the length of the clonal root, is also recorded.

5. The method for optimizing water use strategy of Populus euphratica clones based on infiltration rotational irrigation according to claim 1, characterized in that, In the S300 multi-type sample collection, the soil samples are collected in layers as follows: 20-100cm from the ground surface, with each layer being 20cm apart; 100-350cm from the ground surface, with each layer being 50cm apart. Three sample bottles and one self-sealing bag of soil samples are collected from each layer.

6. The method for optimizing water use strategy of Populus euphratica clones based on infiltration rotational irrigation according to claim 1, characterized in that, In the S300 multi-type sample collection, when sampling surface water, the brown threaded sampling bottle is first cleaned with surface water, and then the sampling bottle is placed in the water and left to stand for 30 seconds; when sampling groundwater, the Bayle tube and sampling bottle are first cleaned with water, the Bayle tube is placed in the well and left to stand for 30 seconds, and then the groundwater in the Bayle tube is transferred into the sampling bottle, and three duplicate samples are collected for both surface water and groundwater.

7. The method for optimizing water use strategy of Populus euphratica clones based on infiltration rotational irrigation according to claim 1, characterized in that, In the S500 data analysis and strategy optimization, when using the direct comparison method, the possible soil layers for water absorption by Populus euphratica clones and mother plants are preliminarily determined by combining the precipitation and strong evaporation fractionation effect in the extremely arid area of ​​the lower reaches of the Tarim River, and this is used to rule out the possibility that precipitation is the main source of water absorption.

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