A method for planting populus euphratica and its companion species by drip irrigation combined with groundwater recharge

Abstract

The application discloses a method for supplementally planting Populus euphratica and its companion species by drip irrigation combined with underground water, and steps are as follows: S1, determining a supplementally planting plot and a water source, and carrying out land preparation; S2, calculating a required Populus euphratica number, and determining a companion species type, a planting mode and a required number; S3, reasonably arranging seedling raising according to a supplementally planting time; S4, carrying out supplementally planting seedling transplanting and seed direct sowing; and S5, reasonably carrying out seedling period management.The method provided by the application has multi-effectiveness, can significantly improve a Populus euphratica forest seed update survival rate, simultaneously fully utilizes topographic advantages and residual flood storage of a previous year, improves water utilization efficiency, and plays a good water-saving role; the method is good in economic practicability, is simple in technical operation and easy to master, is good in material economy and practicability, greatly reduces an ecological forest protection and repair input cost, and is suitable for wide range of popularization and application.

Description

Technical Field

[0001] This invention relates to the field of vegetation restoration technology, and in particular to a method for replanting Populus euphratica and its associated species using drip irrigation combined with groundwater. Background Technology

[0002] Populus euphratien (Populus euphratien) is the oldest and most primitive tree species in the Populus genus. It has strong drought resistance, salt tolerance, wind protection, and sand fixation capabilities, making it a very valuable germplasm resource of resilient forest trees. It has been listed by the Food and Agriculture Organization of the United Nations as a priority forest resource for protection.

[0003] China's poplar forests account for 61% of the world's total poplar forest area, mainly distributed in Inner Mongolia, Gansu, Xinjiang, Ningxia, and Qinghai. Among them, Xinjiang's poplar forests account for 91% of China's total poplar forest area, concentrated in the Tarim River Basin in southern Xinjiang. They are the dominant and leading species in the Tarim River Basin's desert riparian forest ecosystem, playing a crucial role in the ecological balance of the Tarim River Basin. Due to the impact of climate change and human activities, poplar forests face problems such as difficulty in population regeneration and a trend towards simpler community composition and structure. Not only is the area of ​​poplar forests gradually decreasing, but their ecological functions are also gradually weakening. Therefore, strengthening the protection of poplar forest ecosystems to leverage their ecological functions of windbreak and sand fixation and oasis stabilization is of paramount importance to ensuring the safety of agricultural and pastoral production in oases.

[0004] Populus euphratica population regeneration occurs through two methods: seed propagation and root sucker propagation. Seed propagation relies on surface water, and its success depends on the duration of contact between the seeds and the moist surface, as well as the duration of surface water exposure. Root sucker propagation can utilize both groundwater and surface water. Currently, ecological restoration of large-scale natural poplar forests primarily involves raising the groundwater level in the water conveyance area through ecological water transfer projects, or promoting population regeneration and increasing community biodiversity through flood irrigation or natural overflow. These methods have yielded some positive results in poplar forest protection.

[0005] However, during the investigation in the ecological water conveyance area of ​​the Populus euphratica forest, it was found that large areas of overwintering seedlings formed the previous year were rarely seen, reflecting that the existing ecological water conveyance method consumes a large amount of water, but still has some problems in terms of regeneration success rate. The reasons are as follows: First, although the ecological water conveyance project raises the groundwater level in the water conveyance area and effectively promotes root sucker reproduction and Populus euphratica growth, it cannot realize the seed reproduction of Populus euphratica and other associated species. The species diversity of Populus euphratica forest is still very low, and the community structure is difficult to improve. Second, although the water conveyance method of flood irrigation or natural flood overflow provides surface water, which is conducive to the seed reproduction of Populus euphratica and associated species, the water may not meet the seeds if it arrives too early, or the surface water may not be able to germinate and form seedlings if it meets the seeds and the surface water lasts for too long, or the seedlings may not be able to survive the winter due to the short growth period after the surface water recedes.

[0006] This invention provides a new technology for saving water and effectively improving the survival rate of poplar population regeneration and community structure by adopting a method of spring seedling raising, summer transplanting or direct seeding, early drip irrigation followed by groundwater replanting of poplar and its associated species. Summary of the Invention

[0007] The purpose of this invention is to provide a method for replanting Populus euphratica and its associated species by drip irrigation combined with groundwater, in order to solve the problems of large water consumption, low overwintering survival rate, low species diversity, and difficulty in improving community structure in the ecological restoration of large areas of natural Populus euphratica forests by existing technologies.

[0008] To achieve the above objectives, this invention provides a method for replanting Populus euphratica and its associated species using drip irrigation combined with groundwater, the steps of which are as follows:

[0009] S1. Determine the replanting plots and water sources, and level the plots;

[0010] S2. Calculate the required number of poplar trees and determine the species, planting pattern, and required number of associated species;

[0011] S3. Arrange seedling cultivation reasonably according to the replanting time;

[0012] S4. Perform replanting and transplanting of seedlings and direct seeding;

[0013] S5. Reasonable seedling management.

[0014] Preferably, in step S1, the replanting plot is an open space without tree cover; the water source is floodwater accumulated in the low-lying area last year; leveling the plot means that there are no large ditches or depressions so that the water can flow smoothly when drip irrigation is applied, and there is no need to treat weeds.

[0015] Preferably, in step S2, the number of poplar trees is calculated with a plant spacing of 50-60cm and a row spacing of 80cm; the associated species should include shrubs and herbaceous species, and the planting pattern is poplar, shrubs and herbaceous plants planted alternately.

[0016] Preferably, the replanting time in step S3 is one month before the summer flood season; the seedling time of Populus euphratica is from February to April, and the seeds are Populus euphratica seeds collected in the previous year, which are dried and stored at 4°C until the seedling stage; the companion species can be raised as seedlings or sown directly, and the appropriate choice should be made according to the different types of companion species. For seeds with dormancy, dormancy should be broken by conventional methods before sowing or raising seedlings.

[0017] Preferably, in step S3, the seedling raising method is to mix peat moss and river sand evenly at a volume ratio of 4:1, soak them thoroughly with water, scatter the poplar seeds on the surface, and place them in an environment with a temperature of 30-35℃ and a photoperiod of 16h light / 8h darkness to germinate and grow.

[0018] Preferably, in step S4, the poplar seedlings are transplanted with soil attached, the roots are buried 9-13cm deep, the soil is covered and compacted, and the above-ground parts are all retained; the companion species that are sown by seed are sown by trenching, the trenches are 2-3cm deep, and the soil is covered and compacted after sowing.

[0019] Preferably, after transplanting the seedlings and sowing the seeds in step S4, a shade shed 100cm above the ground is built in the replanting area and removed in the afternoon after the seedlings have grown steadily. Before transplanting the seedlings, a main pipeline is set up according to the water source conditions, and drip irrigation tape is laid vertically on both sides of the main pipeline. Then, a pit is dug on one side of the drip irrigation tape drip outlet for transplanting.

[0020] Preferably, in step S5, reasonable seedling management refers to drip irrigation once every 1 day after transplanting and direct seeding, for a total of 3 times, then drip irrigation once every 2 days, for 2 times, then drip irrigation once every 5 days, then drip irrigation once every 7 days, and then drip irrigation once every 10 days until the flood arrives. Then, drip irrigation is carried out twice in mid-June and mid-July of the following year, with an interval of 30 days, and each drip irrigation lasts for 7-8 hours.

[0021] Therefore, the present invention provides a method for replanting Populus euphratica and its associated species using drip irrigation combined with groundwater, the specific technical effects of which are as follows:

[0022] (1) The method provided by the present invention has multiple benefits. In response to the problem of low seed regeneration survival rate of Populus euphratica and its associated species after irrigation by digging ditches or natural flood overflow, the planting technology of flood irrigation, drip irrigation and groundwater combined with seedling raising and transplanting to replant Populus euphratica and its associated species can significantly improve the seed regeneration survival rate of Populus euphratica forest. At the same time, it makes full use of the terrain advantages and the residual flood storage of the previous year, improves water use efficiency, and plays a good water-saving role.

[0023] (2) The method provided by the present invention is economical and practical. From seedling raising, transplanting, setting up drip irrigation facilities and shade protection devices, the technical operation is simple and easy to master. Moreover, the materials are economical and practical, which greatly reduces the investment cost of ecological forest protection and restoration, and is suitable for large-scale promotion and application.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 These are the selected replanted forest areas, with part A showing the water source near the forest area; parts B and C are photos of the replanted area after it has been leveled.

[0027] Figure 2 These are photos of the replanting site before preparation and after irrigation. Part A shows photos after preparation; Parts B and C show photos after irrigation.

[0028] Figure 3 This is a schematic diagram of the drip irrigation tape layout in replanted forest land;

[0029] Figure 4 These are photos of seedlings grown in plug trays. Part A shows poplar, part B shows licorice, part C shows black goji berry, part D shows large-leaved white hemp, part E shows tamarisk, and part F shows plug tray seedlings of bitter bean.

[0030] Figure 5 These are photos of replanted seedlings transplanted and in the field after transplanting. Part A shows the transplanting day and a distant view of the shade structure; Part B shows the transplanted poplar and licorice seedlings; Part C shows the poplar seedlings one month after transplanting; and Part D shows the licorice seedlings one month after direct seeding. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] To make the objectives, technical solutions, and advantages of this application clearer, more thorough, and more complete, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The following detailed descriptions are all illustrations of embodiments, intended to provide further detailed explanation of the present invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0033] Example 1

[0034] A method for replanting Populus euphratica and its associated species using drip irrigation and groundwater includes the following steps:

[0035] S1. Determine the replanting plots and water sources, and level the plots.

[0036] The experimental site was a poplar forest in Awat County, Xinjiang. An open area within the forest, with nearby low-lying land and accumulated floodwater from the previous year, was selected as the drip irrigation water source (see...). Figure 1 The vacant land in Part A of the middle section will be used as replanting plots (see...). Figure 1 (Parts B and C). The replanted areas should be leveled. Strict leveling requirements are not necessary; the goal is to avoid large depressions to ensure smooth water flow for irrigation and drip irrigation. See the image below for the leveled land. Figure 1 Part B and Part C Figure 2 Part A. If weeds are present, no special treatment is required. Allowing weeds to grow, as long as it does not affect seedling growth, is beneficial for maintaining forest biodiversity and wind erosion resistance.

[0037] S2. Calculate the required number of poplar trees, and determine the species of associated plants, planting pattern, and required number.

[0038] The planting pattern involves alternating planting of poplar, shrubs, and herbaceous species, with specific companion species identified. These companion species include tamarisk, saltwort, black goji berry, bell thorn, oleaster, sea buckthorn, licorice, bitter bean, camel thorn, and large-leaved white hemp. The spacing between transplanted poplar, shrubs, and herbaceous species is 50cm, and the row spacing is 80cm. The spacing between directly planted herbaceous species is 0.5cm. The types of companion species are determined based on the plot size, and the required number of poplar and each companion species are calculated separately.

[0039] S3. Arrange seedling cultivation reasonably according to the replanting time.

[0040] Replanting should be done during the summer flood season—one month before August—either early July or late June, following the principle of planting as early as possible.

[0041] After naturally drying the seeds of Populus euphratica and its associated species (Tamarix chinensis, Salicylum indicum, Lycium barbarum, Rhododendron simsii, Elaeagnus angustifolia, Hippophae rhamnoides, Glycyrrhiza uralensis, Sophora flavescens, Alpaca thorn, and Hemp styrax) collected in the previous year, store the Populus euphratica seeds in a refrigerator at 4°C, and store the seeds of the associated species in a paper bag in a dry place at room temperature.

[0042] Populus euphratica seedlings were cultivated in greenhouses from late February to early March using seedling trays. The trays were 6cm × 6cm × 10cm, 21-cell timber seedling trays. Peat moss and river sand were mixed at a volume ratio of 4:1 and then poured into the seedling trays. The bottom of the trays was filled with tap water until the soil was thoroughly moistened. Populus euphratica seeds, stored in a refrigerator, were then scattered onto the moist soil surface and allowed to germinate and grow in an environment with a temperature of 30–35℃ and a photoperiod of 16 hours of light / 8 hours of darkness.

[0043] Tamarix, Saltwort, Black Goji Berry, Bellthorn, Elaeagnus angustifolia, Hippophae rhamnoides, Licorice, Sophora flavescens, and Camel Thorn were raised in seedling trays from late May to early June. Tamarix and Saltwort seeds are small and can be sown directly onto the surface of moist soil without covering. The remaining seeds are covered with 0.5cm of soil after sowing and kept moist. Figure 4 This is a picture of the growth of seedlings in seedling trays of Populus euphratica and some associated species.

[0044] S4. Perform replanting, transplanting seedlings, and direct seeding.

[0045] (1) Replanting seedlings and seed pretreatment: Do not water or water less for one week before transplanting to harden the seedlings and facilitate the separation of soil and seedling tray; For seeds that need to be sown, dormant legume seeds need to break dormancy before sowing, while non-dormant seeds do not need any pretreatment before sowing.

[0046] (2) Pre-planting irrigation treatment of forest land: Water the forest land for 2-3 days before replanting, and flood water for 6-7 hours every day, thoroughly watering the soil of the replanting forest land until the soil layer 50cm from the ground surface is moist. Figure 2 Sections B and C show photos of watering the replanted areas.

[0047] (3) Replanting seedlings and direct seeding:

[0048] Transplanting takes place in early July. Four-month-old poplar seedlings are 20-25cm tall with root lengths of over 25cm. The seedlings of other associated species are one-month-old and are 10-15cm tall with root lengths of over 10cm.

[0049] a. The species configuration for replanting is mainly poplar trees, followed by shrubs such as black wolfberry, bell thorn, salt spike, tamarisk, and herbaceous plants such as licorice, sparse-leaved camel thorn, sophora, and large-leaved white hemp.

[0050] b. The planting pattern for supplementary plant species is to plant trees, shrubs and herbaceous species alternately, with two rows of each type of poplar planted alternately with one row of each type of shrub and herbaceous species.

[0051] c. Determine the spacing between seedlings of trees, shrubs, and herbaceous plants to be 50cm × 80cm. For herbaceous plants, broadcast sowing should be carried out simultaneously with drip irrigation during transplanting, with a plant spacing of approximately 0.5cm. Figure 5Field photos of replanted seedlings and seed-directed seedlings.

[0052] d. Seedling transplanting: Populus euphratica seedlings grow in seedling trays for 3.5 to 4 months and are transplanted when they are 15 to 25 cm tall; Tamarix chinensis, Salicyces cerevisiae, Lycium barbarum, Glycyrrhiza uralensis and Sophora flavescens grow in seedling trays for 20 days to 1 month.

[0053] The main pipeline is installed according to the water source conditions. Drip irrigation tape is laid vertically on both sides of the main pipeline, with the spacing of the drip irrigation tape consistent with the row spacing of the poplar seedlings. The drip irrigation installation is as follows: Figure 3 As shown in the diagram. Dig holes along one side of the drip irrigation line's drip outlet with a hoe, spacing them 50cm apart. When transplanting replanted seedlings, transplant them as a whole seedling from the seedling tray. Remove the seedling from the tray along with its soil and place it in the hole. Bury the roots of the poplar seedlings 9-13cm deep, cover with soil and compact, leaving the above-ground parts intact. For other accompanying seedlings, choose an appropriate burial depth based on the species. See the field transplanting instructions for details. Figure 5 Part A, Part B, and Part C.

[0054] e. Direct seeding: Use a hoe to dig furrows 5cm deep along the drip irrigation tape. Broadcast the seeds of the associated species along the furrows. For black goji berry, licorice, and bitter bean seeds, broadly broadcast them and cover with 2-4cm of soil, then compact. For tamarisk and saltwort seeds, which are smaller, broadcast them along the furrows without covering with soil. Keep the soil in the furrows moist through drip irrigation (see...). Figure 5 Part D).

[0055] S5. Reasonable seedling management

[0056] a. Immediately after transplanting, erect a shade structure 100cm above the ground (see...). Figure 5 The shade structure was removed 4 weeks after the replanted seedlings were transplanted, and no further shading measures were taken in the replanted area the following year.

[0057] b. During the first week after transplanting and direct seeding, drip irrigate once every day for 7-8 hours each time; after 3 consecutive times, drip irrigate once every 2 days, and repeat 2 times; then extend the interval to drip irrigate once every 5 days, then once every 7 days, and then drip irrigate once every 10 days thereafter, until floods arrive and the groundwater level in the forest rises to about 100cm, at which point drip irrigation should be stopped.

[0058] Before winter, the survival rate of replanted and direct-seeded seedlings reached over 95%, and the vegetation coverage of the replanted areas increased to over 85%.

[0059] c. In June of the following year and again in mid-July when the groundwater level is lowest before the flood season, drip irrigation is applied twice consecutively to both overwintered transplanted seedlings and direct-seeded seedlings. Each drip irrigation lasts 7-8 hours. In August, when the groundwater level rises significantly, drip irrigation is discontinued. This ensures a smooth transition between drip irrigation and the increased soil moisture brought by the rising groundwater level, guaranteeing the growth of overwintered transplanted or direct-seeded seedlings. Before winter of the following year, the survival rate of transplanted seedlings is estimated to be over 90%, and the vegetation coverage over 75%.

[0060] Populus euphratica and its associated species are not demanding in terms of soil requirements. They can be planted in aeolian sandy soil, sandy loam, sandy soil, and saline-alkali soil with a soil salinity (total soil salt) of 0.8-1.5% and a pH value below 8.7. However, the soil salinity (total soil salt) must be below 0.6% and the pH value below 7.8 during seed germination and the seedling stage. The suitable area for promotion is the Populus euphratica distribution area in the five northwestern provinces.

[0061] The invention has achieved good results in the ecological restoration project of Populus euphratica forest in Awat County, Xinjiang. It has not only effectively improved the survival rate of Populus euphratica and its associated species, but also provided a technical case for arid areas to replant Populus euphratica and its associated species by drip irrigation using residual floodwater in low-lying terrain without flooding or large-scale flood diversion irrigation measures. It has provided technical support for the protection of the diversity of natural Populus euphratica forests.

[0062] Therefore, the method of replanting Populus euphratica and its associated species by drip irrigation combined with groundwater provided by this invention has multiple benefits. It can significantly improve the seed regeneration survival rate of Populus euphratica forests, while making full use of the terrain advantages and the residual flood storage from the previous year, thus improving water use efficiency and playing a good role in water conservation. The method is economical and practical. From seedling raising, transplanting, and configuring drip irrigation facilities and shade protection devices, the technical operation is simple and easy to master. Moreover, the materials are economical and practical, which greatly reduces the input cost of ecological forest protection and restoration, and is suitable for large-scale promotion and application.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for replanting Populus euphratica and its associated species using drip irrigation combined with groundwater, characterized in that, The steps are as follows: S1. Determine the replanting plots and water sources, and level the plots; S2. Calculate the required number of poplar trees and determine the species, planting pattern, and required number of associated species; S3. Arrange seedling cultivation reasonably according to the replanting time; S4. Perform replanting and transplanting of seedlings and direct seeding; S5. Reasonable seedling management; In step S1, the replanting plot is an open space without tree cover; the water source is floodwater accumulated in the low-lying area last year; leveling the plot means that there are no large ditches or depressions so that the water can flow smoothly when drip irrigation is applied, and there is no need to deal with weeds. In step S2, the required number of poplar trees is calculated with a plant spacing of 50-60cm and a row spacing of 80cm; the companion species must include shrubs and herbaceous species, and the planting pattern is poplar, shrubs and herbaceous plants planted alternately. The replanting time in step S3 is one month before the summer flood season; the seedling time of Populus euphratica is from February to April, and the seeds are Populus euphratica seeds collected in the previous year. After drying, they are stored at 4℃ until the seedling stage; the companion species are transplanted after seedling or sowed directly. The appropriate method is selected according to the different types of companion species. For seeds with dormancy, dormancy is broken by conventional methods before sowing or seedling cultivation. In step S4, the poplar seedlings are transplanted with soil attached, the roots are buried 9-13cm deep, the soil is covered and compacted, and the above-ground parts are all preserved. For companion species that are sown by seed, direct seeding should be done by furrowing, with a furrow depth of 2-3 cm. After sowing, cover with soil and compact. After transplanting the seedlings and sowing the seeds in step S4, a shade shed 100cm above the ground is built in the replanting area. The shade shed is removed in the afternoon after the seedlings have grown steadily. Before transplanting the seedlings, the main pipeline is set up according to the water source. Drip irrigation tape is laid vertically on both sides of the main pipeline. Then, a hole is dug on one side of the drip irrigation tape drip outlet for transplanting. In step S5, reasonable seedling management refers to drip irrigation once every 1 day after transplanting and direct seeding, for a total of 3 times, then drip irrigation once every 2 days, for 2 times, then drip irrigation once every 5 days, then drip irrigation once every 7 days, and then drip irrigation once every 10 days until the flood arrives. Then, drip irrigation is carried out twice in mid-June and mid-July of the following year, with an interval of 30 days. Each drip irrigation lasts for 7-8 hours. In August, the groundwater level rises significantly, and drip irrigation measures are no longer taken.

2. The method for replanting Populus euphratica and its associated species by drip irrigation combined with groundwater according to claim 1, characterized in that: In step S3, the seedling raising method is to mix peat moss and river sand evenly at a volume ratio of 4:1, soak them thoroughly with water, scatter the poplar seeds on the surface, and place them in an environment with a temperature of 30-35℃ and a photoperiod of 16h light / 8h darkness to germinate and grow.

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