Seedling raising method for promoting perpendicular root system extended growth of haloxylon ammodendron

Abstract

The invention belongs to the technical field of forestry cultivation, and particularly relates to a seedling raising method for promoting perpendicular root system extended growth of haloxylon ammodendron. Comprising the steps that S1, sandy soil, a soil moisture preserving agent and a water retaining agent are mixed to serve as a seedling raising substrate, and the seedling raising substrate is loaded in a seedling raising container with the height being 30-50 cm and the diameter being 5-10 cm; s2, seedling containers are orderly arranged and placed in strip-shaped containers, 3-5 haloxylon ammodendron seeds are sown and covered with a seedling substrate, and an initial watering mode penetrates through the germination period and the initial growth period; s3, after the seedlings are stable, first-class watering is used for cultivation, and after 3-5 pairs of true leaves and stems of the haloxylon ammodendron seedlings grow to be lignified, second-class watering is carried out till the seedling raising period ends; s4, performing shading and seedling hardening on the haloxylon ammodendron seedlings with the height of 15-20 cm before outplanting. By means of the method, the root damage risk of field bare-rooted seedlings and the packing phenomenon caused by plastic nutrition bowl seedling raising can be avoided, the vertical roots of the seedlings are long, the quality is high, and high-quality seedling technical guarantee capable of achieving mechanical operation is provided for desert afforestation engineering.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of forestry cultivation, and particularly relates to a seedling raising method for promoting the elongation growth of vertical root systems of Haloxylon ammodendron. BACKGROUND

[0002] Haloxylon ammodendron, as a xerophytic shrub, has important value in desert ecosystem restoration, and its drought resistance is suitable for sand afforestation.

[0003] Current common seedling raising methods mainly adopt field bare-root seedling raising methods, which need to be field dug before seedling transportation, and are prone to root mechanical damage; before transplanting, the seedlings after transportation need to be implemented with false planting treatment, and the survival rate is controlled by the root integrity. When mechanical planting is adopted, the single plant separation is difficult due to the entanglement of bare-root seedling root systems, and still relies on manual seedling separation. In addition, some technologies adopt plastic nutrient pot seedling raising, which can alleviate the transplanting damage problem, but is prone to abnormal development of seedling root systems, such as spiral, lateral growth or rotting in the container, and forms the root coiling phenomenon. After such pot seedling transplanting, artificial water supplement is still needed until the root system penetrates into the underground water layer. Since the afforestation land of Haloxylon ammodendron is mostly located in the desert hinterland, the later water supplement is difficult to implement, and it is urgent to optimize the root system structure from the seedling raising stage, especially to promote the vertical root deep penetration to enhance the self-watering capacity after transplanting. SUMMARY

[0004] The application aims to provide a seedling raising method capable of synchronously improving the survival rate and root vertical development quality of Haloxylon ammodendron seedling raising, which can avoid the root damage risk of field bare-root seedlings and the root coiling phenomenon caused by plastic nutrient pot seedling raising, and has important significance for promoting the wet sand layer to carry out irrigation-free afforestation technology in desert areas.

[0005] To achieve the above-mentioned purpose, the application provides a seedling raising method for promoting the elongation growth of vertical root systems of Haloxylon ammodendron, comprising the following steps: S1, loading a seedling raising substrate into a seedling raising container to obtain a to-be-seeded seedling raising container; The seedling raising substrate comprises sand, soil moisture preservation agent and water retention agent; the soil moisture preservation agent accounts for 7-10% by mass fraction, the water retention agent accounts for 0.3-0.5‰ by mass fraction, and the sand accounts for the balance; The seedling raising container has a height of 30-50 cm and a diameter of 5-10 cm; S2, sequentially arranging the to-be-seeded seedling raising container in a strip-shaped container with a height greater than or equal to 30 cm, filling nursery soil into the strip-shaped container, making the to-be-seeded seedling raising container stand upright, sowing 3-5 Haloxylon ammodendron seeds in the to-be-seeded seedling raising container, then covering the Haloxylon ammodendron seeds with the seedling raising substrate, and using initial watering mode throughout the germination period of the Haloxylon ammodendron seeds and the initial growth period of Haloxylon ammodendron seedlings; S3, when the Haloxylon ammodendron seedlings enter the stable growth period, a first type of watering mode is used for watering cultivation, and when the Haloxylon ammodendron seedlings grow to 3-5 pairs of true leaves and the stems are preliminarily lignified, a second type of watering mode is used for watering cultivation until the end of the seedling raising period; S4, 10-15 days before the planned field, the Haloxylon ammodendron seedlings with a seedling length of 15-20 cm are moved to an outdoor shaded environment for seedling hardening to obtain Haloxylon ammodendron nursery stock.

[0006] In the above method, the soil conservation agent in S1 is 10%, and the water retention agent is 0.5 ‰.

[0007] In the above method, the covering thickness of the seedling substrate on the Haloxylon ammodendron seed is 0.5-1 cm.

[0008] In the above method, the seedling container in S1 is a non-woven fabric seedling bag.

[0009] In the above method, the initial watering mode in S2 is to uniformly water by spraying or a fine-hole watering can until the water seeps out of the bottom of the seedling container, and the seedling substrate humidity is 60±5% during the seed germination period and the initial growth period of the Haloxylon ammodendron seedlings.

[0010] In the above method, the strip-shaped container in S2 is 50 cm long, 20 cm wide, and 30 cm high.

[0011] In the above method, the first type of watering mode in S3 is to inject water 2-3 times per week, and the water injection position is the bottom of the strip-shaped container, and the water level height is 3-5 cm.

[0012] In the above method, the second type of watering mode in S3 is a “watering period-watering interruption period” cycle method for periodic water control. The watering period is that the bottom tray of the strip-shaped container keeps water for 2-3 days. The water interruption period is that when the remaining water in the bottom tray of the strip-shaped container is completely drained and the seedling substrate naturally loses water for 1-2 days and the leaves appear wilting, clear water is injected to a water level height of 3-5 cm.

[0013] Compared with the prior art, the technical scheme provided by the present application at least has the following beneficial effects or advantages: 1, the present application adopts an ultra-long seedling bag with a diameter of 5-10 cm and a height of 30-50 cm, and the narrow diameter design significantly limits the lateral growth space of the root system, effectively avoids the abnormal development phenomena such as root spiral and root entanglement that easily occur in conventional nutrient pots, and forces the taproot to grow vertically downward along the longitudinal direction of the seedling container, forming dominant vertical roots. This directional induction of the root system structure optimizes the subsequent self-tapping of deep underground water capacity when transplanted in sandy soil.

[0014] 2. The Haloxylon ammodendron seedlings obtained in this application can retain the narrow root ball formed in the seedling container in the bag transplanting mode, and the natural form of root tip growth downward is not damaged; the Haloxylon ammodendron seedlings can adapt to the sandy environment in advance in the seedling substrate, and can integrate with the natural sand layer more quickly when transplanted to desert areas. The vertical roots induced to grow can also continue to extend into the deep water layer at an accelerated pace, shortening the time required for transplanted seedlings to achieve water self-sufficiency.

[0015] 3. Thanks to the longer vertical roots after induction and the enhanced ability of vertical roots to penetrate deeply after transplanting, the Haloxylon ammodendron seedlings provided in this application can reach stable underground water sources more quickly and deeply, and their ability to absorb water independently and resist drought is qualitatively improved. This greatly reduces the dependence on, frequency and total water demand for high-intensity artificial watering at the transplanting site, and significantly reduces the difficulty and cost of later maintenance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0017] Figure 1 The Haloxylon ammodendron seedlings obtained in experimental group B; Figure 2 The seedlings of Haloxylon ammodendron obtained from control group B. Detailed Implementation

[0018] The technical solution of the present invention will be described below with reference to embodiments. However, the present invention is not limited to the following embodiments. Unless otherwise specified, the test methods and detection methods described in each embodiment are conventional methods; the reagents and materials described are commercially available unless otherwise specified. Unless otherwise specified, all percentages in the following embodiments refer to mass percentages. Unless otherwise specified, all proportions in the following embodiments refer to mass ratios.

[0019] Seed source: Purchased from Awat County, Aksu Prefecture; Experimental site: Greenhouse of the Xinjiang Branch of the Changji National Germplasm Resource Bank; Ambient temperature: 30℃ at noon, 25℃ in the morning and evening, humidity 20%; Test date: April 27, 2025; Facilities and conditions: The room should be well ventilated and have a stable water supply; if the temperature is too high during the day, the vents can be opened for ventilation and cooling, and if the temperature is too low at night, thermal curtains can be added for insulation and fire can be lit to increase the temperature; the indoor light intensity should reach 26,000 LUX on sunny days.

[0020] Water-retaining agent: agroforestry water-retaining agent; Green Leipu: registration certificate number: agricultural fertilizer (2013) Lin character 6799; Soil conservation agent: agroforestry soil conservation agent with patent application publication number CN109679664A, purchase channel: Shaya County Hengyao Agricultural Service Farmers' Professional Cooperative.

[0021] Example 1 The seedling raising method for promoting the vertical root system of Haloxylon ammodendron to grow is used to cultivate three groups of Haloxylon ammodendron seedlings, 10 seedlings in each group. Time is counted from sowing, and the root system indexes of the Haloxylon ammodendron seedlings cultivated for four months in the example are recorded.

[0022] The seedling raising method for promoting the vertical root system of Haloxylon ammodendron to grow is used to cultivate three groups of Haloxylon ammodendron seedlings, 10 seedlings in each group. Time is counted from sowing, and the root system indexes of the Haloxylon ammodendron seedlings cultivated for four months in the example are recorded. S1, loading the seedling substrate into a non-woven fabric seedling bag with a height of 50 cm and a diameter of 10 cm to obtain a non-woven fabric seedling bag to be sown; The seedling substrate comprises sand, a soil conservation agent and a water-retaining agent. The soil conservation agent accounts for 7%, the water-retaining agent accounts for 0.3‰, and the sand accounts for the balance. S2, orderly arranging the non-woven fabric seedling bag in a strip-shaped flowerpot with a length of 50 cm, a width of 20 cm and a height of 30 cm, and then filling a small amount of nursery soil around the non-woven fabric seedling bag to ensure that the seedling bag is in an upright state. 5 Haloxylon ammodendron seeds are scattered in the non-woven fabric seedling bag to be sown, and then the seedling substrate is covered on the Haloxylon ammodendron seeds with a covering thickness of 1 cm. The seeds are slightly pressed to make the seeds contact with the soil. After sowing, uniform watering is carried out by spraying or a fine-hole watering can until water seeps out from the bottom of the non-woven fabric seedling bag. The moisture of the seedling substrate is kept at about 60% during the period to ensure the smooth germination of the seeds and the initial growth of the seedlings; S3, when the Haloxylon ammodendron seedlings enter the stable growth period, clear water is injected into the bottom of the strip-shaped flowerpot, and the water level height is kept at 3-5 cm during each watering. The water is “absorbed” from the lower part of the container to the upper part by the capillary action of the seedling substrate, so that the container keeps a high soil moisture content in the lower part and a low soil moisture content in the upper part. The plant roots are induced to grow downward actively. After the Haloxylon ammodendron seedlings grow to 3-5 pairs of true leaves and the stems are preliminarily lignified, the “watering period-disconnection period” cycle method is used for periodic water control; The watering period is that the bottom tray of the strip-shaped container keeps water for 2-3 days. The disconnection period is that the remaining water in the bottom tray of the strip-shaped container is completely drained, and when the substrate naturally loses water for 1-2 days and the leaves appear wilting after transplanting, clear water is injected to a water level height of 3-5 cm until the end of the seedling period. S4, 15 days before the nursery is planned, the shuttle shuttle seedlings with a length of 15-20 cm are moved to the outdoor shade environment for seedling training, the flowerpots are moved to the outdoor shade environment during the seedling training period, the tray is completely drained, and no water is added. Let the plant fully adapt to the drought and light environment, and get the shuttle seedling.

[0023] In this embodiment, the root system indexes of the three groups of shuttle seedlings obtained by the above method are averaged, and the final data are shown in Table 1: Table 1: Root system index of shuttle seedlings induced to grow vertically in Example 1 From Table 1, it can be seen that the average number of roots of the shuttle seedlings obtained in this application is 5.67, and the average longest root length reaches 35.67 cm, indicating that through the technology of inducing vertical root growth, the root system of the shuttle seedling develops well, and the rooting ability and main root extension effect are remarkable.

[0024] Example 2 The seedling raising method for promoting the vertical root system of shuttle to extend and grow provided in this embodiment raises three groups of shuttle seedlings, 10 plants in each group. From the time of sowing, the root system indexes of the shuttle seedlings raised for four months in this embodiment are recorded.

[0025] The seedling raising method for promoting the vertical root system of shuttle to extend and grow provided in this embodiment comprises: S1, loading the seedling substrate into a non-woven fabric seedling bag with a height of 30 cm and a diameter of 5 cm to obtain a non-woven fabric seedling bag to be sown; The seedling substrate comprises sand, soil conservation agent and water retention agent; the soil conservation agent is 8%, the water retention agent is 0.4‰, and the sand is the balance; S2, arrange the non-woven fabric seedling bags in a strip-shaped flowerpot with a length of 50 cm, a width of 20 cm and a height of 30 cm, and then fill a small amount of nursery soil around the non-woven fabric seedling bags to ensure that the seedling bags are in an upright state. Sow 3 shuttle seed seeds in the non-woven fabric seedling bag to be sown, and then cover the seedling substrate on the shuttle seed seeds with a thickness of 0.5 cm, and slightly press to make the seeds contact with the soil. After sowing, uniform watering is carried out by spraying or fine hole watering can, until water seeps out from the bottom of the non-woven fabric seedling bag. The humidity of the seedling substrate is kept between 55-65% at all times to ensure the smooth germination of the seeds and the initial growth of the seedlings; S3, when the Haloxylon ammodendron seedlings enter the stable growth period, inject clean water into the bottom of the strip-shaped flowerpot, and keep the water level at 3-5 cm during each watering. The water is "absorbed" upward from the lower part of the container by the capillary action of the seedling substrate, so that the container maintains a high soil moisture content in the lower part and a low soil moisture content in the upper part. The plant roots are induced to grow downward actively. After the Haloxylon ammodron seedlings grow to 3-5 pairs of true leaves and the stems are preliminarily lignified, a "watering period-water interruption period" cycle method is used for periodic water control; The watering period is that the bottom tray of the strip-shaped container keeps water for 2-3 days; the water interruption period is that the remaining water in the bottom tray of the strip-shaped container is completely drained, and when the seedlings naturally lose water for 1-2 days and the leaves appear wilting, clean water is injected to a water level of 3-5 cm until the end of the seedling period; S4, 10 days before the planned nursery, the Haloxylon ammodron seedlings with a seedling length of 15-20 cm are moved to an outdoor shaded environment for seedling hardening. During the seedling hardening period, the flowerpots are moved to an outdoor shaded environment and the tray is completely drained without adding water. The plants are fully adapted to the dry and light environment, and Haloxylon ammodron seedlings are obtained.

[0026] In this embodiment, the root system indexes of the three groups of Haloxylon ammodron seedlings obtained by the above method are averaged, and the final data are shown in Table 2: Table 2: Root system indexes of Haloxylon ammodron seedlings induced to grow vertically in Example 2 From Table 2, it can be seen that the average number of roots of the Haloxylon ammodron seedlings obtained in this application is 4.67, and the average longest root length reaches 31.67 cm, indicating that by the technology of inducing vertical root growth, the root system of Haloxylon ammodron seedlings develops well, and the rootability and main root extension effect are significantly improved.

[0027] Example 3 A seedling raising method for promoting the vertical root system of Haloxylon ammodron to extend and grow is provided in this embodiment. Three groups of Haloxylon ammodron seedlings, each group of 10, are raised, and the root system indexes of the Haloxylon ammodron seedlings raised for four months in this embodiment are recorded from the time of sowing.

[0028] The seedling raising method for promoting the vertical root system of Haloxylon ammodron to extend and grow provided in this embodiment comprises: S1, loading the seedling substrate into a non-woven fabric seedling bag with a height of 40 cm and a diameter of 7 cm to obtain a non-woven fabric seedling bag to be sown; The seedling substrate comprises sand, soil conservation agent and water retention agent; the soil conservation agent is 10%, the water retention agent is 0.5‰, and the sand is the remainder; S2, arrange the non-woven fabric seedling bags in a strip-shaped flowerpot with a length of 50 cm, a width of 20 cm and a height of 30 cm in order, and then fill a small amount of nursery soil around the non-woven fabric seedling bags to ensure that the seedling bags are in an upright state. 4 seeds of the Haloxylon ammodendron seeds are scattered in the non-woven fabric seedling bags to be sown, and then the seedling substrate is covered on the Haloxylon ammodendron seeds, with a covering thickness of 0.8 cm, and the seeds are slightly pressed to make contact with the soil; after sowing, uniform watering is performed by spraying or a fine-hole watering can until water seeps out from the bottom of the non-woven fabric seedling bag. The humidity of the seedling substrate is kept between 55% and 65% at all times to ensure the smooth germination of the seeds and the initial growth of the seedlings; S3, when the Haloxylon ammodendron seedlings enter the stable growth period, inject clean water into the bottom of the strip-shaped flowerpot, and the water level is kept at 3-5 cm each time. The water is "absorbed" from the lower part of the container to the upper part by the capillary action of the seedling substrate, so that the container keeps the lower soil with a high water content and the upper soil with a low water content. The plant roots are induced to grow downward actively. After the Haloxylon ammodendron seedlings grow to 3-5 pairs of true leaves and the stems are preliminarily lignified, the "watering period-disconnection period" cycle method is used for periodic water control; The watering period is that the bottom tray of the strip-shaped container keeps water for 2-3 days; the disconnection period is that the remaining water in the bottom tray of the strip-shaped container is completely drained, and when the substrate naturally loses water for 1-2 days and the leaves appear wilting, clean water is injected to a water level of 3-5 cm until the end of the seedling period; S4, 12 days before the planned nursery, the Haloxylon ammodendron seedlings with a seedling length of 15-20 cm are moved to an outdoor shaded environment for hardening. During the hardening period, the flowerpots are moved to an outdoor shaded environment, and the tray is completely drained without adding water. The plants are fully adapted to the dry and light environment, and Haloxylon ammodendron nursery stock is obtained.

[0029] In this embodiment, the root system indexes of the three groups of Haloxylon ammodendron seedlings obtained by the above method are averaged, and the final data are shown in Table 3: Table 3: Root system indexes of Haloxylon ammodendron seedlings induced to grow vertically in Example 3 From Table 3, it can be seen that the average number of roots of the Haloxylon ammodendron nursery stock obtained in this application is 5.33, and the average longest root length reaches 33.67 cm, indicating that by the technology of inducing vertical root growth, the root system of the Haloxylon ammodendron seedlings develops well, and the rooting ability and main root extension effect are remarkable.

[0030] Example 4 The applicant found that the contradictions of large-scale planting efficiency, transplanting survival rate and root system of shuttle seedling were always the technical bottleneck in the long-term practice of promoting shuttle seedling afforestation project. The operation of artificial root separation is time-consuming and the root damage is difficult to avoid when transplanting conventional bare-root seedlings. Although plastic nutrient pot seedling avoids damage during seedling, more than 80% of the root system is coiled in the pot, which leads to continuous artificial water supply after transplanting. The applicant continuously compares the transplanting cultivation containers and studies the systematic solution, and finally confirms that only the transplanting scheme of non-woven fabric seedling bag can meet the needs of mechanized operation and vertical root development. In order to clearly show the technical differences, the following test is provided for illustration: The three groups of shuttle seedlings with induced vertical root growth obtained in example 1 are taken as experimental group A; The three groups of shuttle seedlings with induced vertical root growth obtained in example 2 are taken as experimental group B; The three groups of shuttle seedlings with induced vertical root growth obtained in example 3 are taken as experimental group C; Three groups of shuttle seedlings are cultivated by conventional method and ordinary seedling pot (10x15cm) for four months, 10 seedlings in each group, to obtain control group A, control group B and control group C.

[0031] A shuttle seedling is randomly selected from experimental group B, as shown in Figure 1 , it can be seen that the number of roots is 5, and the root length is relatively long, which is measured as 32.05cm. A shuttle seedling is randomly selected from control group B, as shown in Figure 2 , it can be seen that the number of roots is 1, and the root length is relatively short, which is measured as 18.63cm.

[0032] The root system indexes of experimental group and control group are compared to obtain table 4: Table 4: comparison data table of root system indexes of experimental group and control group From table 4, it can be seen that the directional guiding effect of the seedling cultivation container with a diameter of 5-10cm and a height of 30-50cm on the root system of shuttle seedling is verified: the longest root length of experimental group shuttle seedling all breaks through 30cm, with an average of 33.67cm, while the average longest root length of control group in shallow pot (height≤15cm) is only 19.67cm. This 14cm root length gap directly reflects the decisive influence of container depth on the vertical extension of taproot: the seedling cultivation container blocks the lateral root coiling through physical barrier, forcing the taproot to grow vertically downward to form dominant vertical root. When transplanting, the experimental group retains the vertical root group with a length of 33cm during bagging transplantation, and the natural form of the root tip vertically downward ensures its continuous deep penetration after transplanting in sandy soil, combined with the pre-adapted sandy environment of the seedling substrate, rapid connection with deep water layer. The deep self-watering capacity thus realized significantly reduces the self-sufficient period of water, providing core support for reducing the maintenance cost of desert afforestation project.

[0033] The above description merely illustrates the principles of the application, the preferred embodiments and its advantages. It will be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the application and are included within its spirit and scope.

Claims

1. A seedling cultivation method for promoting the vertical root extension of Haloxylon ammodendron, characterized in that, include: S1. Load the seedling substrate into the seedling container to obtain the seedling container to be sown; The seedling substrate includes sand, a moisture-retaining agent, and a water-retaining agent; by mass fraction, the moisture-retaining agent is 7-10%, the water-retaining agent is 0.3-0.5‰, and the sand is the remainder; The seedling container has a height of 30-50cm and a diameter of 5-10cm; S2. Arrange the seedling containers to be sown in an orderly manner in a strip container with a height of 30cm or more, then fill the strip container with nursery soil so that the seedling containers to be sown are upright, sow 3 to 5 seeds of Haloxylon ammodendron seedlings in the seedling containers to be sown, and then cover the seeds of Haloxylon ammodendron seedlings with the seedling substrate. Use the initial watering method throughout the seed germination period and the early growth period of Haloxylon ammodendron seedlings. S3. After the Haloxylon ammodendron seedlings enter the stable growth period, water them using the first type of watering method. After the Haloxylon ammodendron seedlings grow to 3-5 pairs of true leaves and the stems begin to lignify, water them using the second type of watering method until the end of the seedling period. S4. 10 to 15 days before the planned delivery of the seedlings, move the 15 to 20 cm long Haloxylon ammodendron seedlings to an outdoor shaded environment to harden them off, and obtain Haloxylon ammodendron seedlings.

2. The method according to claim 1, characterized in that, The moisture-retaining agent in S1 is 10%, and the water-retaining agent is 0.5‰.

3. The method according to claim 1, characterized in that, The seedling substrate covering the Haloxylon ammodendron seeds has a thickness of 0.5-1 cm.

4. The method according to claim 1, characterized in that, The seedling container mentioned in S1 is a non-woven fabric seedling bag.

5. The method according to claim 1, characterized in that, The initial watering method described in S2 is to use a sprayer or a fine-nozzle watering can to water evenly until water seeps out from the bottom of the seedling container. During the seed germination period and early growth period of the Haloxylon ammodendron seedlings, the moisture content of the seedling substrate is 60±5%.

6. The method according to claim 1, characterized in that, The strip container described in S2 is 50cm long, 20cm wide, and 30cm high.

7. The method according to claim 1, characterized in that, The watering method described in S3 involves watering 2-3 times per week, with the water being injected at the bottom of the strip-shaped container, and the water level being 3-5 cm.

8. The method according to claim 1, characterized in that, The second type of watering method described in S3 is: periodic water control using the "watering period - water cut-off period" cycle method; The watering period is as follows: the bottom tray of the strip container is kept with water for 2-3 days; The water cut-off period is as follows: when the remaining water in the bottom tray of the strip is completely drained, and the seedling substrate loses water naturally for 1-2 days and the leaves wilt, clean water is injected until the water level reaches 3-5cm.

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