A planting unit and method for promoting submerged aquatic vegetation using recycled paper pulp

Abstract

The application discloses a planting unit and a method for promoting growth of submerged plants prepared from recycled paper pulp, comprising a planting unit shell base and a planting unit shell cover, which are both made of a mixture of recycled paper pulp fibers, water-soluble polyvinyl alcohol solution, starch and bentonite, the bottom of the planting unit shell base is covered with calcium peroxide, the upper part is filled with planting substrate material, and the gaps are filled with plant growth promoting agents, the top of the planting unit shell cover is provided with a reserved plant hole, and the submerged plants are planted in the planting substrate material through the reserved plant hole. The material is environmentally friendly, has a fast degradation rate, has no environmental hazards after degradation, the configuration of the planting unit substrate can improve the polluted sediment environment, thereby effectively improving the adaptability and stress resistance rate of the submerged plants planted in the polluted water body, thereby improving the survival rate of the submerged plants and reducing the frequency of subsequent reseeding.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water ecological restoration. More particularly, the present application relates to a planting unit and method for promoting submerged plants using recycled paper pulp. BACKGROUND

[0002] As an important part of urban water system, the pollution of shallow lakes directly affects the quality of life of urban residents and the sustainable development of the city. Many shallow lakes have deteriorated water quality, increased eutrophication, and reduced biodiversity, which even affects the quality of life of the surrounding residents. The main reasons for the pollution of urban shallow lakes include the discharge of domestic sewage and industrial wastewater, agricultural non-point source pollution, insufficient ecological water replenishment, and decreased self-purification capacity of water bodies. In recent years, China has made great efforts in the water ecological restoration of urban shallow lakes, and the results have been more significant. In the field of water environmental ecological restoration engineering, it is crucial to restore submerged plants in shallow lakes, and the restoration effect of submerged plants directly affects all aspects of the restoration project. However, in the actual construction process, cutting and throwing are the most commonly used methods for planting submerged plants. Cutting is suitable for shallow water and soft bottom, but it often cannot control the cutting depth, resulting in low survival rate. The throwing method is less affected by water depth and bottom hardness. The soil package of submerged plants is thrown into the water and naturally sinks to the surface of the sediment. As the plant roots grow and penetrate into the sediment, the survival rate is affected by the pollution of the bottom mud. In some areas with serious bottom mud pollution, the conventional planting soil substrate is easily assimilated by the contaminated sediment, which can stress the growth of plants.

[0003] Currently, in order to improve the survival rate of the ecological restoration process of submerged plants in practical engineering applications, multi-stage step-by-step construction is basically adopted, that is, the micro-polluted water environment is improved first, and then the submerged plants are restored. For example, patent CN111170400A adopts multi-stage step-by-step construction, which has the disadvantages of long cycle, high personnel cost and the like. As for the planting method of submerged plants, planting devices such as planting beds, single-plant planting bags or planting cups are mostly used. For example, CN212260057U and CN108401730B. The high-molecular polymer material used in these planting devices has a degradation rate of 78% within 4 months in natural conditions, and microplastics are easily generated during the degradation process, which has potential environmental hazards. The use of the improver for water environment management in the early stage of submerged plant restoration is greatly affected by the weather, and the dosage needs to be adjusted many times, which has a long construction cycle and a complicated process. In the current research, the material of the submerged plant planting device is mostly non-degradable or has a long degradation cycle, and the degradation conditions of part of the device material are harsh, and microplastics are easily generated during the degradation process, which has potential threats to the environment. At the same time, the conventional planting substrate used in these devices has a single function, which only provides good nutrition for the initial planting of submerged plants and has no improvement effect on the environment. Paper pulp fiber has good environmental friendliness, and its degradation rate is better than that of high-molecular polymer material in natural environment. The degradation time of ordinary paper products in natural water is more than 2 weeks, and the modified treatment can further improve its water permeability and degradation rate. The use of waste paper material to extract paper pulp fiber can effectively realize the resource utilization of waste, and improve the recycling rate of waste paper.

[0004] In summary, the current planting device has the disadvantages of slow material degradation rate and single function of the substrate, and a multifunctional planting device with an environmentally friendly material is urgently needed. SUMMARY

[0005] An object of the present application is to provide a submerged plant planting unit and method prepared from recycled paper pulp, which can improve the sediment environment in the planting process of submerged plants under the condition of micro-polluted shallow lake water by combining efficient oxygenation with the use of plant growth promoting bacteria, and has the advantages of environmentally friendly material, fast degradation rate, no environmental hazards after degradation, and the like. The configuration of the substrate of the planting unit can improve the polluted sediment environment and effectively improve the adaptability and stress resistance rate of the submerged plants planted in the polluted water body, thereby improving the survival rate of the submerged plants and reducing the frequency of subsequent reseeding.

[0006] In order to solve the above technical problems, the application provides a planting unit for promoting growth of submerged plants prepared from recycled paper pulp, which comprises a planting unit shell base and a planting unit shell cover body, both of which are hollow structures; the planting unit shell base is an integrated structure of a lower cone and an upper cylinder; the planting unit shell cover body is an integrated structure of an upper cone and a lower cylinder; the planting unit shell base and the planting unit shell cover body are both made of a mixture of recycled paper pulp fiber, water-soluble polyvinyl alcohol solution, starch and bentonite; the lower part of the planting unit shell cover body is placed in the upper part of the planting unit shell base, and the heights of the two are the same and the central axes coincide; the bottom of the planting unit shell base is covered with calcium peroxide; the outer walls of the planting unit shell base and the planting unit shell cover body are filled with a plant growth promoting agent; the remaining space in the planting unit shell base and the planting unit shell cover body is filled with planting substrate material; the top of the planting unit shell cover body is provided with a reserved plant hole, and the submerged plants are planted in the planting substrate material through the reserved plant hole.

[0007] Preferably, the planting substrate material is a mixture of treated medical stone and humus soil, and the mass ratio of the medical stone to the humus soil is 1-2:10; the mass fraction of the water-soluble polyvinyl alcohol solution is 5-15%, and the addition amount of the polyvinyl alcohol solution in the recycled paper pulp modified fiber is 0.5-1 ml / g; the mass ratio of the recycled paper pulp modified fiber, bentonite and starch is 1-3:0.5-1.5:0.5-1.5; and the mass ratio of calcium peroxide, planting substrate and plant growth promoting agent is 1:8-15:1.

[0008] Preferably, the inner diameter of the planting unit shell base is 10-20 cm, the height of the upper cylinder of the planting unit shell base is 5-15 cm, the height of the lower cone of the planting unit shell base is 3-8 cm, the height of the cone of the planting unit shell cover body is 1-5 cm, the diameter of the reserved hole of the planting unit shell cover body is 1-3 cm, and the width of the gap between the outer wall of the planting unit shell cover body and the inner wall of the planting unit shell base is 1-3 cm.

[0009] The application further provides a method for preparing a planting unit for promoting growth of submerged plants from recycled paper pulp, which comprises the following steps:

[0010] Step one, after the recycled waste paper is treated and softened by soaking in water for a set time, the paper pulp fiber is formed by mechanical treatment; the paper pulp fiber is filtered, then soaked in an alkali solution for alkali washing; the alkali washed paper pulp fiber is washed to neutral, and then soaked in a hydrogen peroxide solution; and the recycled paper pulp modified fiber is obtained by filtration;

[0011] Step two, mix the recycled paper pulp modified fiber obtained above with a water-soluble polyvinyl alcohol solution, add starch and bentonite during the mixing process to form a uniform mixture, then spread the mixture onto the mold surface corresponding to the planting unit shell base and the planting unit shell cover, and obtain the planting unit shell base and the planting unit shell cover after demolding;

[0012] Step three, soak the maifanite material with the alkali washing waste liquid filtered out in step one for a certain time, then take out the soaked maifanite material, wash it to neutral, and then mix it with humus to obtain a planting substrate material;

[0013] Step four, pretreat the submerged plants that need to be planted;

[0014] Step five, cover the bottom of the planting unit shell base obtained in step two with a certain thickness of calcium peroxide, then fill the bottom cone structure with the planting substrate material prepared in step three; place the planting unit shell cover obtained in step two into the planting unit shell base, fill the planting substrate material prepared in step three into the internal space through the reserved plant hole at the top of the planting unit shell cover, and fill the plant growth promoting bacteria into the gap between the outer periphery of the planting unit shell cover and the planting unit shell base, to obtain a planting unit base;

[0015] Step six, insert the pretreated submerged plants in step four into the filled planting substrate material through the reserved plant hole at the top of the planting unit shell cover to a certain depth, to obtain a planting unit;

[0016] Step seven, throw the obtained planting unit into the water body and sink to the surface of the sediment to realize the planting of submerged plants.

[0017] Preferably, in step one, the recycled waste paper is corrugated paper waste generated in the express packaging industry or office paper waste; the alkali washing is performed in a 10% mass fraction NaOH solution for 1-3h; the H2O2 solution has a mass fraction of 3% and is soaked for 0.5-2h.

[0018] Preferably, in step two, the mass fraction of the water-soluble polyvinyl alcohol solution is 5-15%, the addition amount of the polyvinyl alcohol solution in the recycled paper pulp modified fiber is 0.5-1ml / g; the mass ratio of the recycled paper pulp modified fiber, bentonite and starch is 1-3:0.5-1.5:0.5-1.5.

[0019] Preferably, in step three, the alkali washing waste liquid soaks the maifanite material for 1.5-3h; the mass ratio of the maifanite and humus is 1-2:10.

[0020] Preferably, in the step four, the submerged plant pretreatment includes: removing rotten, poor growth state leaves and withering plants, and screening the withering plants, and the plants are divided into clusters according to 5-15 plants per cluster; the submerged plants are Vallisneria, Potamogeton, Hydrilla verticillata and Potamogeton crispus.

[0021] Preferably, in the step five, the plant growth promoting bacteria agent includes Bacillus, Azotobacter and Pseudomonas, all in the form of powder, and the mass ratio of the three is 1.5-2.5:0.5-1.5:0.5-1.5, and the cell density of the agent is 3-4.5 billion / g; the mass ratio of calcium peroxide, planting substrate material and the plant growth promoting bacteria agent is 1:8-15:1.

[0022] Preferably, in the step six, the planting depth is 3-5 cm; the inner diameter of the planting unit shell base is 10-20 cm, the height of the upper column of the planting unit shell base is 5-15 cm, the height of the lower cone of the planting unit shell base is 3-8 cm, the height of the cone of the planting unit shell cover is 1-5 cm, the diameter of the reserved hole of the planting unit shell cover is 1-3 cm, and the width of the gap between the outer wall of the planting unit shell cover and the inner wall of the planting unit shell base is 1-3 cm.

[0023] The present application at least includes the following beneficial effects:

[0024] 1. The high-efficiency oxygenation and growth promoting submerged plant planting unit prepared by using waste paper to extract pulp modified fibers is applied to the ecological restoration process of submerged plants in polluted water bodies in shallow lakes under the premise of realizing the resource utilization of waste, and after alkali washing and hydrogen peroxide modification and molding, the unit has good water permeability and degradation performance, is conducive to the contact of the plant growth promoting bacteria agent and the improved agent with the external environment, has no secondary pollution hazard after microbial degradation, is green and friendly, is easy to assemble, and the rapid degradation of the material is conducive to the rapid planting of submerged plants in the sediment, and further improves the sediment improvement effect.

[0025] 2. The substrate configuration of the high-efficiency oxygenation and growth promoting submerged plant planting unit improves the anaerobic state of the sediment and establishes the aerobic microenvironment of the sediment, effectively avoids the assimilation pollution of the planting unit to the planting substrate in the polluted sediment in the early stage of plant planting and growth, effectively realizes the adaptability of the submerged plant in the early stage of planting and growth, improves the survival rate of the submerged plant, and reduces the number of maintenance and reseeding times in the later period.

[0026] Other advantages, objects and features of the present application will be partly embodied by the following description, and partly understood by those skilled in the art through research and practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The figure is a large sample drawing of the high-efficiency oxygenation and growth promoting submerged plant planting unit.

[0028] Figure 2 Schematic diagram of high-efficiency oxygen-increasing and growth-promoting submerged plant planting unit of the present application;

[0029] Figure 3 Base configuration diagram of high-efficiency oxygen-increasing and growth-promoting submerged plant planting unit of the present application;

[0030] Figure 4 Comparison diagram of total phosphorus variation curve of overlying water quality of the present application;

[0031] Figure 5 Comparison diagram of ammonia nitrogen variation curve of overlying water quality of the present application;

[0032] Figure 6 Comparison diagram of phosphorus form variation of bottom mud of the present application;

[0033] Figure 7 Comparison diagram of new leaf number of single plant of Vallisneria plant of the present application;

[0034] Figure 8 Comparison diagram of plant length of single plant of Vallisneria plant of the present application.

[0035] Explanation of reference signs:

[0036] 1-planting unit shell base, 2-planting unit shell cover, 3-calcium peroxide, 4-planting substrate material, 5-plant growth-promoting bacterial agent, 11-submerged plant, 12-planting unit base. DETAILED DESCRIPTION

[0037] In order to better understand the purpose, structure and function of the present application, the present application will be further described in detail below in combination with the drawings, so that those skilled in the art can implement it according to the description.

[0038] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present application, the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0039] In the process of submerged vegetation restoration in urban shallow lake polluted water body, the nitrogen and phosphorus content of the polluted sediment exceeds the standard, which is not conducive to the growth of submerged plants. Without pretreatment of bottom improvement, the effect of submerged plant planting is not good, and the anaerobic environment at the bottom of the polluted water body can easily cause the decay of submerged plants, further deteriorating the water environment. The conventional substrate planting bag can only provide a certain shelter effect for the early growth of submerged plants, and the substrate and polluted sediment will also affect the growth of submerged plants after assimilation under long-term conditions. Moreover, the existing planting bag is made of polyester non-woven fabric, polyethylene mesh and other high molecular polymer materials, which not only has a long degradation period, but also generates microplastics during degradation, which has potential harm to the environment.

[0040] Therefore, the present application uses modified paper pulp fiber extracted from waste corrugated paper to make a rapidly degradable green unit shell material, and combines calcium peroxide, medical stone, humus substrate and plant growth promoting bacteria to prepare a submerged plant planting unit. The new submerged plant planting unit can effectively solve the pollution and assimilation of the planting unit by the polluted sediment, and at the same time realize the improvement of the sediment during the plant planting process. The anaerobic state of the polluted sediment is improved to an aerobic microenvironment by using calcium peroxide, which improves the stress resistance and survival rate of the submerged plants during planting and reduces the frequency of planting submerged plants. Compared with the traditional process of first improving the sediment and then restoring the submerged plants, the sediment improvement effect is integrated into the submerged plant planting process, which simplifies the process of submerged plant restoration to a certain extent.

[0041] Considering the actual application of the existing water body ecological restoration technology process, the present application summarizes a high-efficiency oxygen-increasing and growth-promoting submerged plant planting unit prepared from recycled paper pulp and its construction method. The planting unit provided by the present application has a rapidly degradable submerged plant planting unit without secondary pollution after degradation and has a certain bottom improvement effect. The purpose is to improve the planting survival rate in the project, and at the same time, to improve the sediment environment of the slightly polluted water body.

[0042] As Figures 1 to 3As shown, the present application provides a kind of planting unit for promoting growth of submerged plants prepared by recycled paper pulp, comprising planting unit shell base 1 and planting unit shell cover 2, which are all hollow structures, the planting unit shell base is the integrated structure of lower cone and upper cylinder, the planting unit shell cover is the integrated structure of upper cone and lower cylinder, the planting unit shell base and the planting unit shell cover are all made of recycled paper pulp fiber, water-soluble polyvinyl alcohol solution, starch and bentonite by mixing to form a mixture, the planting unit shell cover is placed in the upper part of the planting unit shell base, and the height and central axis of the two are the same, the bottom of the planting unit shell base is covered with calcium peroxide 3, the outer wall between the planting unit shell base and the planting unit shell cover is filled with plant growth promoting agent 5, the remaining space of the planting unit shell base and the planting unit shell cover is filled with planting substrate material 4, the top of the planting unit shell cover is provided with a reserved plant hole, and the whole is formed into a planting unit base 12, and the submerged plants 11 are planted in the planting substrate material through the reserved plant hole.The planting substrate material is the mixture of treated rhyolite and humus soil.

[0043] The present application also provides a method for preparing a planting unit for promoting growth of submerged plants using recycled paper pulp, which is realized by the following steps:

[0044] Step one: after removing surface glue-like substances and other impurities from recycled waste paper, cut it into small pieces, and put the corrugated paper pieces into water to soak for 0.5-2h to soften, and disperse the paper pulp fibers by constant stirring and rubbing; after filtering the water, the paper pulp fibers are soaked in 10% NaOH solution for 1-3h, then the alkali-washed paper pulp fibers are washed to neutral with water, and then soaked in 3% H2O2 solution for 0.5-2h, after filtering the solution, the modified recycled paper pulp fibers are obtained; the source of waste paper can be discarded corrugated paper generated in express packaging industry, discarded paper generated in office field, and discarded paper pulp fiber products such as household waste paper.

[0045] Step two: mix the recycled paper pulp modified fiber with the water-soluble polyvinyl alcohol solution uniformly, add starch and bentonite during the mixing process to form a uniform mixture, spread the mixture on the surface of the mold, and after extrusion molding, put it in an oven at 60-80℃ for drying and hardening demolding, and check for no obvious breakage after demolding to obtain the recycled paper pulp modified fiber planting unit base and cover; the mass fraction of water-soluble polyvinyl alcohol solution is 5-15%, and the addition amount of polyvinyl alcohol solution in recycled paper pulp modified fiber is 0.5-1ml / g. The mass ratio of recycled paper pulp modified fiber, bentonite and starch is 1-3:0.5-1.5:0.5-1.5. The use of bentonite and starch can improve the strength of the recycled paper pulp modified fiber planting unit material after hardening and molding, and at the same time, it can speed up the expansion and dispersion of the planting unit shell after being put into water. Starch can be used as a carbon source for microbial growth, which is conducive to the attachment and growth of microorganisms and speeds up the degradation rate of the shell.

[0046] Step three: soak the zeolite material in the alkali washing waste liquid filtered out in step one for 1.5-3h, clean the internal pores of the zeolite, improve the adsorption performance of the zeolite, and then wash it to neutral with pure water and mix it evenly with humus to prepare a planting unit planting substrate material; the mass ratio of zeolite to humus is 1-2:10.

[0047] Step four: pretreat the submerged plants that need to be planted, remove the rotten and poorly growing leaves, and sieve out the withered and rotten plants, and divide them into 5-15 plants per clump for standby use; the submerged plants are Vallisneria, Potamogeton, Hydrilla verticillata, and Potamogenton crispus, etc.

[0048] Step five: cover a layer of calcium peroxide on the bottom of the recycled paper pulp modified fiber planting unit base, fill the bottom cone structure with the planting unit substrate material, put the recycled paper pulp modified fiber planting unit cover into the base, fill the planting substrate material through the plant hole reserved on the cover, and fill the plant growth promoting bacterial agent in the gap between the cover and the base, to prepare a recycled paper pulp modified fiber planting unit base. The calcium peroxide used is food-grade calcium peroxide with an effective content of 99%. The mass ratio of calcium peroxide, planting substrate and plant growth promoting bacterial agent is 1:8-15:1. The plant growth promoting bacterial agent is a commercially available agent, and the types are Bacillus, Azotobacter and Pseudomonas, with a mass ratio of 1.5-2.5:0.5-1.5:0.5-1.5. All are powders, and the bacterial agent cell density is about 30-45 billion / g.

[0049] Step six: using a sharp mouth clamp to insert the submerged plant roots into the planting substrate material 3~5cm deep through the reserved plant hole of the cover, to obtain the recycled paper pulp modified fiber planting unit, which is thrown into the water body to settle on the surface of the sediment to realize the planting of submerged plants. The planting unit size is 10~20cm in diameter, 5~15cm in cylindrical height, 3~8cm in base cone height, 1~5cm in cover cone height, 1~3cm in cover reserved hole diameter, and 1~3cm in the width of the gap between the cover outer wall and the base inner wall.

[0050] The application not only provides a high-efficiency oxygen-increasing and growth-promoting submerged plant planting unit prepared from recycled paper pulp, but also provides a construction method for on-site planting. The planting unit using calcium peroxide high-efficiency improvement agent, adsorptive mineral substrate material and humus as planting substrate and matching with plant growth-promoting bacteria has multiple effects of sediment improvement and plant growth promotion. The planting unit material is environmentally friendly, has fast degradation speed and no secondary pollution in degradation. The survival rate of submerged plants can be improved by sediment improvement in urban shallow lakes with water depth of ≤1.5m and water transparency of ≤0.5m under the condition of slight pollution, and the frequency of reseeding can be reduced.

[0051] In order to better understand the essence of the application, the technical content of the application is described below with specific examples. The efficiency and survival rate of submerged plant planting are improved by planting unit configuration under the condition of water depth of ≤1.5m and water transparency of ≤0.5m in urban shallow lakes. However, the content of the application is not limited to this.

[0052] Example 1: a high-efficiency oxygen-increasing and growth-promoting submerged plant planting unit prepared from recycled paper pulp is prepared by the following method:

[0053] (1) ground soil is put into a wide-mouth plastic bucket, organic materials such as hay, fallen leaves and straw are added to the soil and mixed uniformly to obtain organic soil, the mass ratio of ground soil to organic material is 1:1, a small amount of red sugar yeast liquid is sprayed on the mixed organic soil and compacted, a layer of 1cm-thick ground soil is covered on the upper layer of the compacted organic soil, and the mixture is placed in a normal temperature condition for fermentation for 1 month to obtain humus;

[0054] (2) after the waste corrugated paper generated from the express delivery industry is recycled, the surface glue-like substances are removed, the corrugated paper is cut into small pieces, the corrugated paper pieces are soaked in water for 1 hour to soften, and the paper pulp fibers are dispersed by constant stirring and rubbing; the filtered paper pulp fibers are soaked in a 10% NaOH solution for 1.5h, the alkali-washed paper pulp fibers are washed to neutral with water, and then soaked in a 3% H2O2 solution for 1h, the solution is filtered, and the obtained recycled paper pulp modified fiber is taken out.

[0055] (3) 50 g of recycled paper pulp modified fiber, 25 g of bentonite, and 25 g of starch were mixed uniformly, and then 25 ml of 5% water-soluble polyvinyl alcohol solution was added and stirred into a paste to prepare a recycled paper pulp modified fiber shell wet material;

[0056] (4) The recycled paper pulp modified fiber shell wet material was evenly spread on the mold and extruded into a conical cylinder structure with a diameter of 15 cm and a height of 20 cm. The mold was placed in an oven at 80°C for 2 hours for curing. After drying, the mold was removed, and the planting unit recycled paper pulp modified fiber shell base and cover were obtained after inspection for no obvious damage;

[0057] (5) A layer of 5 g of powdered calcium peroxide was spread on the bottom of the planting unit recycled paper pulp modified fiber shell base. A mixture of 5 g of maifanite (100 mesh particle size) and 45 g of humus soil was prepared and filled into the bottom cone. The remaining planting medium was filled into the cover with a pre-prepared plant hole. Then, 5 g of plant growth promoting bacteria was filled into the gap between the planting unit recycled paper pulp modified fiber shell base and the cover, and the planting unit base was obtained.

[0058] (6) The root of the submerged plant seedling was inserted into the planting medium of the planting unit base using a tool to a depth of about 4 cm, ensuring that the submerged plant was fixed in the medium and could not easily fall off, and the complete planting unit was obtained.

[0059] The present situation of pollution lake water and sediment was taken from a certain area of Wuhan Jin Yinhu, and the water depth was simulated to be 50 cm and the black and odorous sediment thickness to be 20 cm under indoor conditions. The prepared planting unit was put into the simulated water body, and the degradation rate of different material planting bags in a certain time was observed, and the changes of nitrogen and phosphorus in the sediment and lake water were monitored.

[0060] As shown in Figure 4 and Figure 5 and Figure 6 show the curves of water quality (total phosphorus and ammonia nitrogen content) and sediment phosphorus form content of different material planting bags under the conventional substrate of the submerged plant paper pulp planting unit.

[0061] Figure 4 and Figure 5 show that the planting unit can significantly reduce the influence of conventional cutting method on water quality caused by sediment suspension. The calcium peroxide at the bottom of the planting unit can effectively improve the anaerobic conditions of the sediment and promote the nitrogen and phosphorus purification of the water body during the growth of the submerged plant to a certain extent. Figure 6The results show that the calcium peroxide at the bottom of the planting unit improves the redox potential of the anaerobic sediment, promotes the generation of exchangeable phosphorus (organic phosphorus and non-apatite phosphorus) in the sediment, and the exchangeable phosphorus can be utilized by the submerged plants and microorganisms to achieve the effect of removing phosphorus.

[0062] Example 2

[0063] The application of the high-efficiency oxygen-promoting submerged plant planting unit prepared from recycled paper pulp in the construction of lake submerged plant planting is as follows:

[0064] 1) The application was implemented in a restoration area of Jin Yin Lake in Wuhan City, Hubei Province. First, the water level was lowered to about 1 m, 10 seedlings of Vallisneria densesperma were planted in each planting bag according to the demand, and the planting density was ensured to be 50 plants / m 2 ; at the same time, non-woven fabric planting bags and PVC mesh planting bags of pure humus soil were tested.

[0065] 2) The new paper pulp planting bag and the comparative planting bag were put into the water body for regular monitoring and maintenance. The survival of submerged plants in the experimental area was monitored on the 10th, 20th and 30th day, and once a month thereafter. According to the maintenance and monitoring situation of the test area, the rotten floating plants were salvaged and cleaned. The growth state of the plants was recorded on the 5th, 10th, 20th and 30th day.

[0066] Table 1 and Figure 7 and Figure 8 shown below, is the survival and growth state of Vallisneria densesperma in the planting process of the comparative non-woven fabric planting bag of pure humus soil, the PVC mesh planting bag and the planting unit of the application.

[0067] Table 1 Survival of Vallisneria densesperma

[0068]

[0069] As can be seen from the above chart, the planting of submerged plants through the planting unit can significantly improve the stress resistance of submerged plants in polluted sediment. The number of new leaves and the length of the plant of Vallisneria densesperma are superior to those of conventional planting bags and conventional cutting method planting, and have a certain plant promoting effect.

[0070] The shell of the planting unit can achieve a degradation rate of 50% within 3 days in the lake water body, and can achieve a degradation rate of 79.5% within 7 days, which is significantly faster than the degradation rate of high molecular polymer materials. The rapid degradation of the shell material is conducive to the planting of submerged plants in the sediment and further purifies the polluted sediment.

[0071] It is to be understood that the present application is described by way of example only, and that modifications or alterations can be made to the features and embodiments described without departing from the spirit and scope of the application. Although embodiments of the present application have been disclosed in connection with the enumerated embodiments, the present application is not limited to those embodiments. Rather, it is intended to embrace all alternatives, modifications and substitutions as is permitted by the scope of the claims and equivalents thereof.

Claims

1. A submerged plant cultivation unit for promoting growth using recycled pulp, characterized in that, The device includes a hollow planting unit outer shell base and a planting unit outer shell cover. The planting unit outer shell base is an integrated structure of a lower cone and an upper column, and the planting unit outer shell cover is an integrated structure of an upper cone and a lower column. Both the planting unit outer shell base and the planting unit outer shell cover are made of recycled pulp fiber, water-soluble polyvinyl alcohol solution, starch, and bentonite mixed together. The lower part of the planting unit outer shell cover is placed inside the upper part of the planting unit outer shell base, and the two are at the same height and their central axes coincide. The bottom of the planting unit outer shell base is covered with calcium peroxide. The space between the outer walls of the planting unit outer shell base and the planting unit outer shell cover is filled with plant growth-promoting bacteria. The remaining space of the planting unit outer shell base and the planting unit outer shell cover is filled with planting substrate material. The top of the planting unit outer shell cover is provided with reserved plant holes, through which submerged plants are planted in the planting substrate material.

2. The submerged plant cultivation unit prepared using recycled pulp as described in claim 1, characterized in that, The planting substrate material is a mixture of treated maifanite and humus, with a mass ratio of maifanite to humus of 1~2:10; the mass fraction of water-soluble polyvinyl alcohol solution is 5~15%, and the amount of polyvinyl alcohol solution added to the recycled pulp modified fiber is 0.5~1ml / g; the mass ratio of recycled pulp modified fiber, bentonite, and starch is 1~3:0.5~1.5:0.5~1.5; and the mass ratio of calcium peroxide, planting substrate, and plant growth promoter is 1:8~15:

1.

3. The submerged plant cultivation unit prepared using recycled pulp as described in claim 1, characterized in that, The inner diameter of the base of the implantation unit outer shell is 10~20cm, the height of the upper column of the base of the implantation unit outer shell is 5~15cm, the height of the lower cone of the base of the implantation unit outer shell is 3~8cm, the height of the cone of the cover of the implantation unit outer shell is 1~5cm, the diameter of the reserved hole in the cover of the implantation unit outer shell is 1~3cm, and the width of the gap between the outer wall of the cover of the implantation unit outer shell and the inner wall of the base of the implantation unit outer shell is 1~3cm.

4. A method for preparing submerged plant planting units using recycled pulp, characterized in that, Includes the following steps: Step 1: After processing the recycled waste paper, soak it in water for a set time to soften it. During this process, mechanical processing is used to form pulp fibers. Filter the pulp fibers and then soak them in an alkaline solution for alkaline washing. Wash the alkaline-washed pulp fibers with water until neutral, and then soak them in a hydrogen peroxide solution. Filtration yields recycled pulp modified fibers; Step 2: Mix the recycled pulp modified fiber obtained above with water-soluble polyvinyl alcohol solution. During the mixing process, add starch and bentonite to form a homogeneous mixture. Then spread the mixture onto the mold surface corresponding to the planting unit outer shell base and the planting unit outer shell cover. After demolding, the planting unit outer shell base and the planting unit outer shell cover are obtained. Step 3: Soak the maifan stone material in the alkaline washing waste liquid filtered in Step 1 for a set time, then take out the soaked maifan stone material and wash it until it is neutral, then mix it evenly with humus to obtain the planting substrate material for the planting unit. Step 4: Pre-treat the submerged plants that need to be planted; Step 5: Cover the bottom of the planting unit outer shell base obtained in Step 2 with calcium peroxide of a set thickness, and then fill the bottom cone structure with the planting substrate material prepared in Step 3; place the planting unit outer shell cover obtained in Step 2 into the planting unit outer shell base, fill the internal space with the planting substrate material prepared in Step 3 through the plant holes reserved at the top of the planting unit outer shell cover, and fill the gap between the outer periphery of the planting unit outer shell cover and the planting unit outer shell base with plant growth-promoting bacteria to obtain the planting unit base; Step 6: Insert the submerged plants treated in Step 4 into the pre-drilled plant holes at the top of the planting unit's outer shell and set the depth to obtain the planting unit. Step 7: Throw the obtained planting units into the water body and let them sink to the bottom mud surface to achieve the establishment of submerged plants.

5. The method for preparing submerged plant cultivation units using recycled pulp as described in claim 4, characterized in that, In step one, the recycled waste paper is waste corrugated paper generated by the express packaging industry or waste paper or waste pulp fiber products generated in the office field; alkaline washing is carried out in a 10% NaOH solution for 1-3 hours; and soaking is carried out in a 3% H2O2 solution for 0.5-2 hours.

6. The method for preparing a submerged plant cultivation unit using recycled pulp as described in claim 4, characterized in that, In step two, the water-soluble polyvinyl alcohol solution has a mass fraction of 5-15%, and the amount of polyvinyl alcohol solution added to the recycled pulp modified fiber is 0.5-1 ml / g; the mass ratio of recycled pulp modified fiber, bentonite, and starch is 1-3:0.5-1.5:0.5-1.

5.

7. The method for preparing a submerged plant cultivation unit using recycled pulp as described in claim 4, characterized in that, In step three, the alkali washing waste liquid is used to soak the maifan stone material for 1.5 to 3 hours; the mass ratio of maifan stone to humus is 1 to 2:

10.

8. The method for preparing a submerged plant cultivation unit using recycled pulp as described in claim 4, characterized in that, In step four, the pretreatment of submerged plants includes: removing rotten or poorly growing leaves and sifting out withered and rotten plants, and dividing the plants into clumps of 5 to 15 plants each for later use; the submerged plants are Vallisneria natans, Potamogeton crispus, Hydrilla verticillata, and Potamogeton crispus.

9. The method for preparing a submerged plant cultivation unit using recycled pulp as described in claim 4, characterized in that, In step five, the plant growth-promoting microbial agent includes Bacillus, nitrogen-fixing bacteria, and Pseudomonas, all in powder form, with a mass ratio of 1.5~2.5:0.5~1.5:0.5~1.5 and a cell density of 30~45 billion / g; the mass ratio of calcium peroxide, planting substrate material, and plant growth-promoting microbial agent is 1:8~15:

1.

10. The method for preparing a submerged plant cultivation unit using recycled pulp as described in claim 4, characterized in that, In step six, the planting depth is 3-5cm; the inner diameter of the planting unit outer shell base is 10-20cm; the height of the upper column of the planting unit outer shell base is 5-15cm; the height of the lower cone of the planting unit outer shell base is 3-8cm; the height of the cone of the planting unit outer shell cover is 1-5cm; the diameter of the reserved hole in the planting unit outer shell cover is 1-3cm; and the width of the gap between the outer wall of the planting unit outer shell cover and the inner wall of the planting unit outer shell base is 1-3cm.

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