CN108575710B

CN108575710B - Method for cultivating poplar seedlings by using water sand

Info

Publication number: CN108575710B
Application number: CN201810167203.8A
Authority: CN
Inventors: 陈志凡; 郭瑞超; 张成丽; 王岩松; 刘鹏飞
Original assignee: Henan University
Current assignee: Henan University
Priority date: 2018-02-28
Filing date: 2018-02-28
Publication date: 2020-03-31
Anticipated expiration: 2038-02-28
Also published as: CN108575710A

Abstract

The invention belongs to the technical field of environmental pollution plant restoration, and relates to a method for cultivating poplar seedlings by using water sand, which comprises the following steps: (1) preparing a water culture nutrient solution; (2) taking poplar cuttings; (3) storing the poplar cutting slips in a wide-mouth container filled with a water culture nutrient solution for later use; (4) inserting the cutting into a flowerpot filled with coarse sand; (5) putting the flowerpot into an open tray filled with the water culture nutrient solution; (6) adjusting and keeping the pH value of the water culture nutrient solution in the open tray between 6.5 and 6.8; (7) a small submersible pump is arranged in the open tray; (8) carrying out twice spraying treatment on the cuttings every day for about two weeks; (9) and taking out the poplar seedlings when the root systems and branches and leaves of the poplar cuttings grow out and enter a rapid growth period. The method not only considers the conditions of root respiration and cutting and ground establishing, but also considers the requirements of moisture balance and nutrients, and provides convenience for the application research and practice of the poplar in the sewage ecological engineering.

Description

Method for cultivating poplar seedlings by using water sand

Technical Field

The invention belongs to the technical field of plant restoration for environmental pollution, and particularly relates to a method for cultivating poplar seedlings by using water sand.

Background

With the acceleration of the urbanization process and the rapid development of economy, the amount of municipal sewage derived from domestic wastewater and enterprise wastewater is increasing. Although a large amount of sewage can enter the urban sewage treatment plant through the urban sewage pipe network to be treated in a centralized way, a certain amount of heavy metals, boron and substances such as nitrogen, phosphorus and the like which easily cause eutrophication of water bodies still exist in the treated urban tail water. Therefore, the urban tail water after centralized treatment is directly discharged into a clear water area closely related to human beings, and still has great danger. The problem of trace toxic pollution in urban tail water is increasingly emphasized in developed countries. Therefore, before the sewage is discharged into a clean water environment, the treatment of urban tail water mainly comprising the effluent of a sewage treatment plant is enhanced, and the treatment is very important for eliminating conventional organic pollutants or trace toxic pollutants. The comprehensive ecological sewage engineering based on land treating system or wet land and mainly comprising soil percolation, microbe absorption, plant root absorption, etc. is ideal tail water treating technology.

Phytoremediation technology is considered to be a promising green and environment-friendly approach to remediation. Poplar is increasingly applied to the research in the technical field of environmental pollution remediation because of its fast growth speed, large biomass, developed root system, wide distribution and strong adaptability. However, how to well cultivate a large amount of poplar cutting seedlings for water culture simulation experiments directly affects the repair effect of poplar on polluted water and experimental results. The existing common direct-cutting soil or matrix seedling raising method is easy to cause low survival rate of seedlings due to the fact that the seedlings lose moisture balance, weak stress resistance and the like, or is inconvenient to be directly used for water culture simulation experiments or water environment restoration. Therefore, a more suitable method for raising seedlings of poplar by cutting is needed to be explored.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides the method for cultivating the poplar seedlings by the water sand, which considers the conditions of root respiration and ear-cutting and ground-setting, also considers the requirements of moisture balance and nutrients, and provides convenience for the application research and practice of the poplar in the sewage ecological engineering.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for cultivating poplar seedlings by using water sand comprises the following steps:

step 1: mixing water-soluble fertilizer Peters Professional General Purpose pure apple 20-20-20 and water according to the mass ratio of 1:2000, and then adding NaCl and CaCl₂Obtaining water culture nutrient solution; the NaCl and CaCl₂The total concentration in the water culture nutrient solution is 7.97 mM/L;

step 2: cutting to obtain 24.5-25.5 cm cuttings, and storing the cuttings in a wide-mouth container filled with a water culture nutrient solution for later use; the diameter of the cross section of the cutting is 1.5-2 cm, and the distance between the lower end shearing opening and the nearest bud point is 6 cm;

and step 3: filling coarse sand with the particle size of 0.5-2 mm into a flowerpot with the height of 10cm and the caliber of 10cm, wherein the upper surface of the coarse sand is 1cm lower than the edge of the pot opening, and then inserting the cutting slips into the flowerpot filled with the coarse sand;

and 4, step 4: placing the flowerpot with the cutting slips into an open tray filled with water culture nutrient solution, wherein the liquid level of the water culture nutrient solution in the open tray is 1/2-2/3 of the height of the flowerpot; meanwhile, good ventilation and illumination conditions of the cuttings are kept, and in order to prevent the liquid level of the water culture nutrient solution from being reduced due to evaporation, purified tap water is added into the open tray every day to keep the liquid level at 1/2-2/3 of the height of the flowerpot.

And 5: dropwise adding a proper amount of nitric acid to adjust and keep the pH value of the water culture nutrient solution in the open tray to be 6.5-6.8;

step 6: the gaps of each row of flowerpots in the open tray are sequentially U-shaped and inverted U-shaped, 2-3 water pipes are arranged in a crossed mode, a small submersible pump is installed on each water pipe to maintain the circulation of the water culture nutrient solution, further maintain the uniform concentration of the water culture nutrient solution and the aeration of oxygen, and provide continuous nutrient conditions and proper oxygen for the development of the poplar root system.

And 7: uniformly spraying the cuttings twice every day for two weeks; the uniform spray treatment adopts distilled water or purified tap water.

And 8: and taking out the poplar seedlings when the roots and branches and leaves of the poplar cuttings grow out and enter a rapid growth period, and washing the roots of the poplar seedlings with distilled water to be clean, so that the poplar seedlings can be used for a poplar water culture simulation experiment or large-area planting.

Further, NaCl and CaCl are described in step 1₂In a molar ratio of 1: 4.

Further, the liquid level height of the water culture nutrient solution in the step 2 does not exceed 1/3 of the length of the cutting, and the cutting is preserved for no more than 4 days through the step.

Further, in the step 3, 4-6 layers of fine-hole abrasive cloth are laid on the pot bottom pad before coarse sand is filled into the flowerpot to prevent sand from leaking out, and the aperture of the fine-hole abrasive cloth is smaller than 0.5 mm; the bottom of the cutting is 1-2 cm away from the bottom of the pot, and the number of the bud points reserved on the cutting above the upper surface of the coarse sand is 2-3.

Further, the method also comprises the step 3-8 that the temperature for culturing the cutting shoots is 22-25 ℃.

The invention has the beneficial effects that:

1. the survival rate of the poplar seedlings cultivated by the method can reach 100 percent at most, which is higher than that of the existing cutting seedling technology.

2. The method fully considers the problems of water retention and balance and oxygen maintenance during the rooting and leaf-expanding period of the cutting slips of the poplar, wherein the period from the cutting to the rooting and leaf-expanding period of the cutting slips generally needs 2-4 weeks, and the cutting slips are most easy to lose water balance and have weak stress resistance. The method can lead the poplar to adapt to the aquatic environment in advance, and is convenient to be used in a water culture simulation experiment or cultivated in a wetland for assisting the restoration of the polluted water body in the later period.

3. The pH value of the water culture nutrient solution is kept in a weak acid state of 6.5-6.8, so that the biological effectiveness of the water culture nutrient solution is enhanced, and the absorption and utilization of nutrient elements in the water culture nutrient solution by poplar are facilitated.

4. The small submersible pumps are distributed in the open tray, so that the water culture nutrient solution can be in a circulating flowing state, the concentration uniformity of the water culture nutrient solution and the aeration of oxygen are further kept, continuous nutrient conditions and proper oxygen are provided for the development of the root system of the poplar, the adaptability of the poplar seedling to the water environment is enhanced, and the poplar seedling can be kept in a good growing state.

5. The fertilizer Peters Professional General Purpose apple 20-20-20 in the water culture nutrient solution contains N, P and K which are main nutrient components required by plants, and also contains Mg, B, Cu, Fe, Mn, Mo, Zn and the like which are trace elements required by the plants, and the nutrient state required by the growth of poplar trees can be met by a solution obtained by mixing the fertilizer and water according to the mass ratio of 1: 2000; NaCl and CaCl₂The salinity of the water culture nutrient solution is close to but slightly higher than the normal range of the salinity of fresh water, which is beneficial to promoting the growth of the poplar rhizome. Proper amount of CaCl₂The addition of the NaCl salt is beneficial to relieving the toxicity of pure NaCl on the growth of poplar, and simultaneously, the salinity component is closer to the natural water state. The water culture nutrient solution is more commonThe Hoagland nutrient solution is more convenient to prepare, is beneficial to large-scale use, and is easy to be absorbed by plants compared with the traditional chemical fertilizer.

6. Coarse sand with the thickness of 0.5 mm-2 mm is adopted, so that the method is favorable for meeting the field conditions required by the growth of the poplar cutting slips; but also is beneficial to water and air permeation, and is convenient for root respiration and absorption of nutrient elements.

Drawings

Fig. 1 is a schematic diagram of the arrangement of a small submersible pump and a water pipe in an open tray in embodiment 1.

FIG. 2 shows the survival rate of water sand seedlings of different poplar varieties in example 2.

Fig. 3 is a schematic diagram of the arrangement of a small submersible pump and a water pipe in the open tray in embodiment 2.

In the drawings are labeled: 1 is open tray, 2 is small-size immersible pump, and 3 is first water pipe, and 4 are the second water pipe, and 5 are the flowerpot, and 6 are the third water pipe.

Detailed Description

The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

6 poplar varieties used in the examples: 195- & ltSUB & gt 529 (P.trichocarpa. times.P.delids), DTAC-1 (P.trichocarpa. times.P.delids), NE-222 (P.delids. times.P.nigra cv. Caudina), DN-34 (P.delids. times.P.nigra), OP-367 (P.delids. times.P.nigra), and 57-276 (P.trichocarpa. times.P.delids) were all purchased from Segal Ranch, USA.

Example 1

The method for cultivating the young seedlings of the poplar DTAC-1 by using the water sand comprises the following steps:

step 1: a water-soluble fertilizer Peters Professional General Purpose apple 20-20-20 (formula is detailed in Table 1) is prepared by mixing the following components in a proportion of 1: 10 (mass ratio of water-soluble fertilizer to water) to prepare a fertilizer concentrated solution, diluting the fertilizer concentrated solution according to the mass ratio of 1:200, and then adding NaCl and CaCl₂Obtaining water culture nutrient solution; the NaCl and CaCl₂The total concentration in the water culture nutrient solution is 7.97 mM/L;

step 2: selecting a poplar variety DTAC-1(P.trichocarpa multiplied by P.deltoids), shearing to obtain 100 cuttings of 24.5cm, and storing the cuttings in a wide-mouth container filled with a water culture nutrient solution for later use; the diameter of the cross section of the cutting is 1-1.5 cm, and the distance between the lower end shearing opening and the nearest bud point is 6 cm;

and step 3: filling coarse sand with the particle size of 0.5-2 mm into a flowerpot 5 with the height of 10cm and the caliber of 10cm, wherein the upper surface of the coarse sand is 1cm lower than the edge of a pot opening, and then inserting the cutting slips into the flowerpot 5 filled with the coarse sand;

and 4, step 4: putting the flowerpot 5 with the cutting slips into an open tray 1 filled with water culture nutrient solution, wherein the liquid level of the water culture nutrient solution in the open tray 1 is 1/2-2/3 of the height of the flowerpot 5, keeping good ventilation and illumination conditions of the cutting slips, and adding purified tap water into the open tray 1 every day to keep the liquid level at 1/2-2/3 of the height of the flowerpot 5 in order to prevent the liquid level from being reduced due to evaporation of the water culture nutrient solution;

and 5: adjusting and keeping the pH value of the water culture nutrient solution in the open tray 1 to be 6.5 by dripping nitric acid;

step 6: the method comprises the following steps that a first water pipe 3 and a second water pipe 4 are sequentially arranged in a U-shaped and inverted U-shaped mode in a crossed mode in gaps of each row of flowerpots 5 in an open tray 1, as shown in figure 1, the water flow direction in the first water pipe 3 is clockwise, the water flow direction in the second water pipe 4 is anticlockwise, and a small submersible pump 2 is respectively installed on the first water pipe 3 and the second water pipe 4 to maintain the circulation of water culture nutrient solution, so that the concentration of the water culture nutrient solution is kept uniform, oxygen is exposed, and continuous nutrient conditions and a proper amount of oxygen are provided for the growth of poplar roots;

and 7: carrying out uniform spraying treatment on the cuttings at nine am and four pm every day for two weeks; the uniform spraying treatment adopts distilled water or purified tap water;

The result shows that the survival rate of the water sand seedling of the poplar variety DTAC-1(P.trichocarpa multiplied by P.deltoids) is 95.92%.

TABLE 1 formula table of water soluble fertilizer Peters Professional General Purpose pure 20-20-20

The content in the table represents the mass percent of the substance in the water-soluble fertilizer Peters Professional General Purpose pure 42 20-20-20.

Example 2

The method for cultivating poplar seedlings by using water sand comprises the following steps:

step 1: a water-soluble fertilizer Peters Professional General Purpose apple 20-20-20 (formula is detailed in Table 1) is prepared by mixing the following components in a proportion of 1: 10 (mass ratio of water-soluble fertilizer to water) to prepare a fertilizer concentrated solution, diluting the fertilizer concentrated solution according to the mass ratio of 1:200, and then adding NaCl and CaCl₂Obtaining water culture nutrient solution; the NaCl and CaCl₂The total concentration in the water culture nutrient solution is 7.97mM/L, NaCl and CaCl₂In a molar ratio of 1: 4.

Step 2: selecting 6 poplar varieties: 195-529(P.trichocarpa x P.deltoids), DTAC-1(P.trichocarpa x P.deltoids), NE-222(P.deltoids x P.nigra cv.Caudina), DN-34(P.deltoids x P.nigra), OP-367(P.deltoids x P.nigra) and 57-276(P.trichocarpa x P.deltoids), cutting to obtain 25cm cuttings, wherein the diameter of the cross section of each cutting is 1.5cm, and the cuttings with the distance of 6cm between the first lateral bud at the upper end, the intact cut at the lower end and the nearest bud point are selected. 50 cutting shoots are selected from each poplar variety, and the total number of the cutting shoots is 300. 25 cuttings of each variety are bundled into a bundle, and the bottom end of each variety is wrapped by a preservative film to temporarily keep moisture. Then removing the preservative film, vertically and dispersedly placing the cutting slips in beakers filled with the water culture nutrient solution, wherein 10 cutting slips are placed in each beaker, and the liquid level height of the water culture nutrient solution does not exceed 1/3 of the length of the cutting slips, so as to ensure that the cutting slips do not lose water.

And step 3: laying 5 layers of fine-hole gauze on the bottom of a flowerpot 5 with the height of 10cm and the caliber of 10cm so as to prevent sand from leaking, wherein the pore diameter of the fine-hole gauze is less than 0.5mm, then filling coarse sand with the particle size of 0.5-2 mm into the flowerpot 5, and the upper surface of the coarse sand is lower than the edge of the flowerpot opening by 1 cm; meanwhile, the poplar cutting slips are inserted into a flowerpot 5 filled with coarse sand, the distance between the bottom of each cutting slip and the bottom of the pot is about 1cm, and the number of the cutting slip reserved buds above the upper surface of the coarse sand is 2.

And 4, step 4: placing the flowerpot 5 with the poplar cutting in the open tray 1 filled with the water culture nutrient solution, keeping the liquid level in the open tray 1 at 1/2 of the height of the flowerpot 5, and keeping good ventilation and illumination conditions of the cutting. To prevent the water-culture nutrient solution from decreasing in level due to evaporation, purified tap water was added daily to open tray 1 to maintain the level at 1/2 of the height of flowerpot 5. The open trays 1 are impervious trays of 70cm (length) x 60cm (width) x 8cm (height), and 16 flowerpots 5 with the height of 10cm and the caliber of 10cm can be placed in each open tray 1 by 4.

And 5: measuring the pH of the hydroponic nutrient solution in the open tray 1 with a portable pH meter every 2 days, and adding HNO dropwise₃Adjusting and keeping the pH value of the water culture nutrient solution in the open tray 1 to be 6.5-6.8.

Step 6: the first water pipe 3, the second water pipe 4 and the third water pipe 6 are sequentially arranged in a U-shaped and inverted U-shaped manner in the gap of each row of flowerpots 5 in the open tray 1 in a crossed manner, as shown in figure 3, the water flow direction in the first water pipe 3 and the third water pipe 6 is clockwise, the water flow direction in the second water pipe 4 is anticlockwise, and the first water pipe 3, the second water pipe 4 and the third water pipe 6 are respectively provided with a small submersible pump 2 to maintain the circulation of the water culture nutrient solution, further maintain the concentration uniformity of the water culture nutrient solution and the exposure of oxygen, and provide continuous nutrient conditions and proper amount of oxygen for the development of the poplar root system.

And 7: during the cutting cultivation period, the poplar cutting shoots are uniformly sprayed by a spray tap at nine am and four pm every day, and distilled water or purified tap water is adopted for uniform spraying treatment, and the treatment lasts for two weeks.

And 8: when the root system and branches and leaves of the poplar cutting slips grow out and enter a rapid growth period, carefully taking out the poplar seedlings, and washing the roots of the poplar seedlings with distilled water to be clean, so that the poplar water planting simulation experiment can be carried out or large-area planting can be carried out.

The whole experiment process is completed in a greenhouse, and the indoor temperature is kept at 25 ℃.

In this example, the survival rates of the water sand seedlings of the 6 poplar varieties were 96.00%, 98.11%, 100.00%, 97.96%, 96.08%, and 96.15%, respectively, as shown in fig. 2.

Example 3

The method for cultivating seedlings of poplar varieties 57-276 (P.trichocarpa. times.P.deltoids) by using water sand comprises the following steps:

Step 2: selecting a poplar variety 57-276(P. trichocarpa multiplied by P. deltoids), shearing to obtain a cutting slip, wherein the length of the cutting slip is 24.5cm, the diameter of the cross section of the cutting slip is 1.5cm, selecting 100 cutting slips with the first side bud at the upper end of the cutting slip intact and the distance of 6cm between the cutting opening at the lower end and the nearest bud point, bundling every 25 cutting slips into a bundle, and wrapping the bottom end with a preservative film to temporarily keep moisture. Then removing the preservative film, vertically and dispersedly placing the cutting slips in beakers filled with the water culture nutrient solution, wherein 10 cutting slips are placed in each beaker, and the liquid level height of the water culture nutrient solution does not exceed 1/3 of the length of the cutting slips, so as to ensure that the cutting slips do not lose water.

And step 3: laying 4 layers of fine-hole abrasive cloth on the bottom of a flowerpot 5 with the height of 10cm and the caliber of 10cm, wherein the aperture of the fine-hole abrasive cloth is less than 0.5mm so as to prevent sand from leaking out, then filling coarse sand with the particle size of 0.5 mm-2 mm into the flowerpot 5, and the upper surface of the coarse sand is 1cm lower than the edge of the flowerpot opening; meanwhile, the poplar cutting slips are inserted into a flowerpot 5 filled with coarse sand, the distance between the bottom of each cutting slip and the bottom of the pot is about 1-1.5 cm, and the number of the cutting slip retaining buds above the upper surface of the coarse sand is 2.

And 4, step 4: placing the flowerpot 5 with the poplar cutting in the open tray 1 filled with the water culture nutrient solution, keeping the liquid level in the open tray 1 at 2/3 of the height of the flowerpot 5, and keeping good ventilation and illumination conditions of the cutting. To prevent the water-culture nutrient solution from decreasing in level due to evaporation, purified tap water was added daily to open tray 1 to maintain the level at 2/3 of the height of flowerpot 5. The open trays 1 are impervious trays 70cm (length) x 60cm (width) x 8cm (height), and 16 flowerpots 5 with the height of 10cm and the caliber of 10cm can be placed in each open tray 1, wherein the number of the flowerpots is 4 x 4.

And 5: measuring the pH value of the water culture nutrient solution in the once-opened tray 1 by using a portable pH meter, and dropwise adding HNO₃Adjusting and keeping the pH value of the water culture nutrient solution in the open tray 1 to be 6.5-6.8, wherein the time interval of adjusting the pH value is 2 days.

Step 6: the U-shaped and inverted U-shaped cross arrangement of the first water pipe 3, the second water pipe 4 and the third water pipe 6 is sequentially arranged in the gap of each row of flowerpots 5 in the open tray 1, the water flow direction in the first water pipe 3 and the third water pipe 6 is clockwise, the water flow direction in the second water pipe 4 is anticlockwise, the small submersible pumps 2 are respectively arranged on the first water pipe 3, the second water pipe 4 and the third water pipe 6 to maintain the circulation of the water culture nutrient solution, further the concentration uniformity of the water culture nutrient solution and the exposure of oxygen are maintained, and continuous nutrient conditions and proper oxygen are provided for the development of poplar root systems.

And 7: during the cutting cultivation period, the poplar cutting shoots are uniformly sprayed by a spray water faucet every nine am and four pm every day, and the uniform spraying treatment adopts distilled water or purified tap water and lasts for two weeks.

The whole experimental process is completed in a greenhouse, and the indoor temperature is kept at 22 ℃.

In this example, the survival rate of the water sand seedlings of the poplar variety 57-276 (P.trichocarpa. times.P.deltoids) was 100%.

Example 4

Seedlings of poplar variety DN-34 (p.delids × p.nigra) were cultivated using water sand, in a manner similar to that of example 3, except that:

the poplar variety selected in the step 2 is DN-34 (P.delids multiplied by P.nigra), the length of the cutting shoot is 25.5cm, and the diameter of the cross section of the cutting shoot is 1 cm;

in the step 3, 6 layers of fine-hole abrasive cloth are padded on the bottom of the flowerpot 5, and the number of the cuttings reserved above the upper surface of the coarse sand is 3; the time interval for pH adjustment in step 5 was 3 days.

In this example, the survival rate of the seedling of the poplar variety DN-34 (P.deltoids. times.P.nigra) in the sand mold is 98.60%.

The above-mentioned embodiments are merely preferred embodiments of the present invention, which are merely illustrative and not restrictive, and it should be understood that other embodiments may be easily implemented by those skilled in the art by means of replacement or modification according to the technical contents disclosed in the specification, and therefore, all changes and modifications that come within the spirit and technical conditions of the present invention should be included in the claims of the present invention.

Claims

1. A method for cultivating poplar seedlings by using water sand is characterized by comprising the following steps:

step 1: mixing water-soluble fertilizer Peters Professional General Purpose pure apple 20-20-20 and water according to the mass ratio of 1:2000, and then adding NaCl and CaCl₂Obtaining water culture nutrient solution; the NaCl and CaCl₂The total concentration in the water culture nutrient solution is 7.97 mM/L; the NaCl and CaCl₂In a molar ratio of 1: 4;

and 4, step 4: putting the flower pot with the cutting slips into an open tray filled with water culture nutrient solution, wherein the liquid level of the water culture nutrient solution in the open tray is 1/2-2/3 of the height of the flower pot, and adding purified tap water into the open tray every day to keep the liquid level at 1/2-2/3 of the height of the flower pot;

and 5: adjusting and keeping the pH value of the water culture nutrient solution in the open tray to be 6.5-6.8 by dropwise adding nitric acid;

step 6: 2-3 water pipes are crossly arranged in a U shape and an inverted U shape in sequence in gaps of each row of flowerpots in the open tray, and each water pipe is provided with a small submersible pump;

and 7: uniformly spraying the cuttings twice every day for two weeks; the uniform spraying treatment adopts distilled water or purified tap water;

and 8: and taking out the poplar seedlings when the roots and branches and leaves of the poplar cuttings grow out and enter a rapid growth period, and washing the roots of the poplar seedlings clean by using distilled water, so that the seedlings can be used for a poplar water culture simulation experiment or large-area planting.

2. The method for water-sand cultivation of poplar seedling as claimed in claim 1, wherein the liquid level of said water culture nutrient solution in step 2 is not more than 1/3 of the length of said cutting, and the time for preserving said cutting by said step is not more than 4 days.

3. The method for cultivating poplar seedlings by using water sand as claimed in claim 1, wherein the flowerpot in the step 3 is covered with 4-6 layers of fine-meshed gauze on the pot bottom pad before coarse sand is filled in the flowerpot, and the pore diameter of the fine-meshed gauze is less than 0.5 mm; the bottom of the cutting is 1-2 cm away from the bottom of the pot, and the number of the bud points reserved on the cutting above the upper surface of the coarse sand is 2-3.

4. The method for cultivating poplar seedlings by using water sand as claimed in claim 1, wherein the temperature for the ear-cutting cultivation in steps 3-8 is 22-25 ℃.