CN111066623A

CN111066623A - Preparation method of lignin fiber-based urea formaldehyde foam culture medium

Info

Publication number: CN111066623A
Application number: CN201911278768.4A
Authority: CN
Inventors: 陈卓异
Original assignee: Nanjing Siyu Environmental Protection Technology Co ltd
Current assignee: Nanjing Siyu Environmental Protection Technology Co ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2020-04-28

Abstract

The invention relates to a preparation method of a lignin fiber-based urea aldehyde foam culture medium, belonging to the technical field of culture. According to the invention, the lignin fiber-based urea formaldehyde foam culture substrate is prepared by adding starch and acrylic acid, the starch and the acrylic acid react to generate starch super absorbent resin, the super absorbent resin is a hydrophilic high polymer with a three-dimensional space network structure, the water absorption of the super absorbent resin comprises physical adsorption and chemical adsorption, the physical adsorption means that the super absorbent resin absorbs water through a capillary tube, the water escapes under pressure, the chemical adsorption means that hydrophilic groups in the super absorbent resin firmly adsorb the water through chemical bonds, the adsorption capacity of the super absorbent resin is very strong, and the water cannot escape even under higher pressure, so that the water retention capacity of the culture substrate is effectively improved.

Description

Preparation method of lignin fiber-based urea formaldehyde foam culture medium

Technical Field

The invention relates to a preparation method of a lignin fiber-based urea aldehyde foam culture medium, belonging to the technical field of culture.

Background

The lawn industry gradually enters a stable development period after starting and rapidly developing, and the lawn is generally applied to landscaping and landscaping of cities and playground construction in China. However, the lawn industry in our country has a great gap from developed countries in the world, and is closely related to the lag in lawn research, in addition to the reasons for history and economic development. In order to promote the development of the lawn industry in China and shorten the gap between the lawn industry and developed countries, scientific research beneficial to the development of the lawn industry must be strengthened on the basis of fully mastering the current situation of research on the lawn science. Therefore, scientific research in the field of lawn planting management is of great importance. The ecological environment is the basic condition for human survival and development and is the basis for social and economic development. With the continuous development of economy in China, the improvement of ecological environment is gradually emphasized. The lawn planting is an effective measure for preventing water and soil loss, conserving water sources and keeping the balance of an ecological system, but the traditional lawn planting is time-consuming and labor-consuming, is difficult to control pests and weeds, causes serious damage to soil layers of a lawn cultivation field in the lawn transplanting process, and has high production cost. The urea-formaldehyde agricultural technology is a new technology which is the youngest and has the greatest development prospect in agricultural production, and the urea-formaldehyde resin foam is a brand-new research field. The urea formaldehyde foam culture substrate is combined with environmental protection, which is not only the requirement of environmental protection, but also a new breakthrough in the field of soilless culture of the lawn.

The research on the soilless culture substrate of the lawn grass in China starts relatively late, and some scholars in China take perlite, sawdust, coal slag, non-woven fabrics, household garbage and other materials as substrates to perform the research on the soilless culture of the lawn grass aiming at various problems in the lawn production. At present, the research on the soilless culture substrate of the lawn in China mainly focuses on three aspects of organic substrates, inorganic substrates and mixed substrates. Common organic substrate raw materials comprise grass fiber, straw, cotton mill noil, wheat straw fiber, waste cotton fiber, fly ash, municipal sludge and the like. The materials have wide sources, low cost, rich medium and trace elements, short production period and degradability, so that the problem of industrial and agricultural wastes can be solved, and the production cost of the lawn can be reduced.

At present, relatively few reports exist in China on singly adopting inorganic materials as lawn culture substrates. Mainly because the inorganic matrix has low content of nutrient substances and poor water and fertilizer retention capability, if nutrient solution is adopted for irrigation, the application cost is relatively high, the operation difficulty is high, and negative effects on the environment are possibly generated, so that the large-scale lawn cultivation by using the inorganic matrix has certain difficulty. However, in recent years, rock wool, sand, polypropylene fiber non-woven fabric, waste colloidal particles, foam plastics and the like are adopted as soilless culture media for lawns in China.

The soilless culture substrate of the lawn in China mainly focuses on the research of the mixed substrate. For example, organic substrates such as decomposed grass fiber, wood fiber, vinegar residue, straw, sludge, peat soil, chicken manure, peat soil, flax and the like and inorganic substrates such as perlite, furnace slag, vermiculite, sand, perlite, terylene and the like are proportioned for lawn planting. The mixed culture medium can change the defects of a single culture medium, so that the properties of C/N, volume weight, porosity, nutrient content, water retention, air permeability and the like of the culture medium are more in line with the requirements of growth and development of turfgrass, and the mixed culture medium is a system which is stable, strong in buffering performance and good in root system growth environment.

The research of the foreign lawn soilless culture substrate is early. The research direction mainly utilizes industrial and agricultural wastes to produce soilless culture organic substrates, such as peat, coconut fibers, piled barks, sawdust, cane sugar, carbonized rice hulls, mushroom residues, reed foam, humus, kenaf fibers and the like. The organic substrates have the advantages of high porosity, strong nitrogen fixation capacity, good water and fertilizer retention performance, strong microbial activity and the like, so the organic substrates become the main raw materials of the soilless culture substrates for the lawn grass.

The urea-formaldehyde foam is a slow-release culture substrate formed by the reaction of urea and formaldehyde under the catalysis of acid. They are composed of polymers containing methylene ureas of varying molecular weights which differ in their solubility or rate of degradation in water or soil. The effectiveness of urea-formaldehyde fertilizer nitrogen in soil is related to the percentage of nitrogen that is insoluble in cold water and insoluble in hot phosphate buffer. The urea formaldehyde cold water soluble component is urea and a short chain polymer, the nitrogen nitration speed of the component is equivalent to that of the urea, the hot water insoluble component is a long chain polymer, and the nitrogen of the component is generally considered to be inactive in soil; the hot water soluble component is a medium chain length polymer, the nitrogen of which is slowly nitrifiable within 6 months in many soils.

In recent years, urea formaldehyde fertilizer is widely applied in America, Western Europe, Japan and other countries as a novel fertilizer, but the research on the aspect of urea formaldehyde resin foam culture medium is rarely reported, so that the research on the urea formaldehyde resin foam soilless culture medium formula is carried out according to the production characteristics of lawns in China, the application effect of the urea formaldehyde resin foam soilless culture medium formula on festuca arundinacea lawns is explored, and the urea formaldehyde fertilizer has important significance for improving the utilization rate and the fertilizer efficiency of nitrogen, promoting the healthy growth of lawn grasses, reducing the environmental pollution, and promoting the sustainable and healthy development of land resources in China.

The main mode of lawn roll production in China is direct land seeding, and the lawn rolls with soil are sold after the lawn is formed. Because the production is repeated on the same land, the method has great destructiveness to the soil structure, and operators usually do not apply or apply little organic fertilizer, so that the secondary salinization of the soil is increasingly serious. Foreign production procedures are largely the same as China, but backfilling and other organic matter measures are adopted to make up for the production plots after each harvest, and basic conditions are provided for sustainable production of the lawn. However, domestic production enterprises can rarely do so to reduce production cost, and the method for backfilling soil is difficult to implement in China with short cultivated land.

The traditional lawn production method has the disadvantages of high cost, long growth period, poor quality and serious weed damage, and the mature soil layer of about 3cm needs to be taken away each time the turf is transplanted, so that the structure of the soil is seriously damaged, and meanwhile, the transportation cost is high, and the paving effect is poor. The steps of 'shoveling and paving the turf' are troublesome, the working efficiency is low, the resource waste is easily caused, the growth of the turf is greatly influenced by the terrain and the climate, and the diseases and the pests of the turf are serious. In the process of lawn maintenance, the problem of environmental pollution is easily caused by lawn fertilization, which not only causes pollution of nitrate in underground water, but also causes a large amount of pesticide and pollution to soil and underground water due to the fact that the healthy growth of the lawn is influenced and diseases and insect pests are caused because the lawn fertilization is unreasonable.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aiming at the problems of low content of nutrient substances in an inorganic matrix, poor water and fertilizer retention capability, relatively high application cost and large operation difficulty due to the adoption of nutrient solution for irrigation, the preparation method of the lignin fiber-based urea formaldehyde foam culture matrix is provided.

In order to solve the technical problems, the invention adopts the following technical scheme:

(1) adding corn starch into deionized water, and stirring at the rotating speed of 200-240 r/min for 10-16 min at normal temperature to obtain a starch solution;

(2) adding lignin fiber powder into a starch solution, stirring at the normal temperature at the rotating speed of 600-800 r/min for 20-30 min, placing in an ultrasonic dispersion machine, and performing ultrasonic dispersion at the normal temperature for 20-30 min to obtain a mixed dispersion liquid;

(3) adding a urea-formaldehyde resin solution, acrylic acid, ammonium persulfate and glycerol into the mixed dispersion liquid, and stirring at the normal temperature at the rotating speed of 400-500 r/min for 30-40 min to obtain a mixed system;

(4) adding soybean protein powder, sucrose, carboxymethyl cellulose and chitosan into a mixed system, placing the mixed system in a high-shear emulsifying machine, and stirring the mixture for 2 to 4 hours at the normal temperature at the rotating speed of 10000 to 12000r/min to obtain a foaming system;

(5) and (3) drying the foaming system in an oven at 70-80 ℃ for 8-10 h, and cooling at normal temperature to obtain the lignin fiber-based urea formaldehyde foam culture medium.

The weight parts of the lignin fiber, the urea-formaldehyde resin solution, the corn starch, the acrylic acid, the soybean protein powder, the sucrose, the carboxymethyl cellulose, the chitosan, the ammonium persulfate, the glycerol and the deionized water are 40-60 parts of the lignin fiber, 80-120 parts of the urea-formaldehyde resin solution, 20-30 parts of the corn starch, 16-24 parts of the acrylic acid, 28-42 parts of the soybean protein powder, 8-12 parts of the sucrose, 10-15 parts of the carboxymethyl cellulose, 6-9 parts of the chitosan, 0.2-0.3 part of the ammonium persulfate, 4-6 parts of the glycerol and 80-120 parts of the deionized water.

And (3) the power of the ultrasonic dispersion in the step (2) is 400-500W.

The specific preparation steps of the lignin fiber powder in the step (2) are as follows:

(1) adding sodium hydroxide into deionized water, and stirring at the normal temperature at the rotating speed of 180-200 r/min for 10-20 min to obtain a sodium hydroxide solution;

(2) adding the wood chips into a sodium hydroxide solution, and stirring at a rotating speed of 240-280 r/min for 40-60 min under a water bath condition of 80-90 ℃ to obtain a wood chip suspension;

(3) placing the wood chip suspension in an ultrasonic dispersion machine, ultrasonically shaking for 20-30 min at normal temperature, filtering, taking filter residue, washing the filter residue to be neutral by using deionized water, and placing the filter residue in a drying oven at 60-80 ℃ for drying for 1-2 h to obtain lignin fibers;

(4) and (3) putting the lignin fiber into a grinding machine, and grinding for 1-2 hours at the normal temperature at the rotating speed of 200-240 r/min to obtain lignin fiber powder.

The wood dust, the sodium hydroxide and the deionized water are 50-60 parts by weight of wood dust, 20-24 parts by weight of sodium hydroxide and 200-240 parts by weight of deionized water.

And (4) the power of the ultrasonic oscillation in the step (3) is 300-400W.

The urea-formaldehyde resin solution prepared in the step (3) comprises the following specific preparation steps:

(1) adding 2/3 urea and melamine into formaldehyde, adjusting the pH value to 7.4-7.8, and stirring and reacting for 1-2 hours at a rotating speed of 200-240 r/min under a water bath condition of 70-80 ℃ to obtain a reaction solution;

(2) adding the residual 1/3 urea into the reaction solution, adjusting the pH value to 5.2-5.6, reacting at the temperature of 80-90 ℃ in a water bath for 30-40 ℃, and then placing in the temperature of 40-50 ℃ in a water bath for heat preservation for 1-2 hours to obtain a reaction solution;

(3) and cooling the reaction liquid to room temperature, dropwise adding a sodium hydroxide solution with the mass fraction of 10% to adjust the pH value to be neutral, and stirring at the rotation speed of 300-400 r/min for 10-20 min at the room temperature to obtain the urea-formaldehyde resin solution.

The formaldehyde, the urea and the melamine are 100-120 parts by weight of 30% formaldehyde by mass, 50-60 parts by weight of urea and 5-6 parts by weight of melamine.

The pH adjustment in the step (1) adopts ammonia water with the mass fraction of 1%.

The pH value adjustment in the step (2) adopts 10 percent of formic acid by mass.

Compared with other methods, the method has the beneficial technical effects that:

(1) the invention takes urea-formaldehyde resin solution as raw material to prepare a lignin fiber-based urea-formaldehyde foam culture substrate, the urea-formaldehyde foam is a slow-release culture substrate formed by acid catalysis of the reaction of urea and formaldehyde, the urea-formaldehyde foam is composed of methylene urea polymers with different molecular weights, the solubility or degradation rate of the methylene urea with different molecular weights in water or soil are respectively in a non-phase state, the effectiveness of urea-formaldehyde fertilizer nitrogen in the soil is related to the percentage of nitrogen insoluble in cold water and insoluble in hot phosphate buffer solution, the cold water soluble components of urea formaldehyde are urea and short chain polymers, the nitrification speed of the nitrogen of the urea formaldehyde is equivalent to that of urea, the hot water insoluble components are long chain polymers, the nitrogen of the urea is inactive in the soil, the hot water soluble components are medium chain polymers, and the nitrogen of the urea can be slowly nitrified in a plurality of soils within six months, thereby achieving the effect of slowly releasing and providing nutrients, the urea formaldehyde foam plastic can absorb solution containing nutrients and other agricultural preparations, and keep the solution and other agricultural preparations in the solution, and then slowly release the solution, so that bacteria in soil can decompose the urea formaldehyde foam plastic to release nitrogen, so that the foam is mixed into the soil to play a role of a fertilizer carrier and a fertilizer, and the nutrients can be prevented from being washed away when the water is excessively lost and the rain is heavy during drought;

(2) the invention takes the soybean protein powder as the foaming agent to prepare the lignin fiber-based urea formaldehyde foam culture medium, the soybean protein powder contains a large amount of protein, the protein is a complex organic compound which takes amino acid as a basic composition unit and has a certain space structure, the protein molecules have hydrophilicity and lipophilicity, the air bubbles formed by rapid stirring can stably exist in the culture medium, the protein has stronger foaming capacity, can be directly extracted from animals and plants, has very wide source and relatively low price, the protein can not generate toxic gas to pollute the air when being decomposed, can not cause threat to the body health of operators, the protein molecules have better intermiscibility with water, have smaller surface tension, contain more active hydrogen, can generate hydrogen bonds with water molecules, reduce the evaporation of water in the culture medium, maintaining the water content of the culture medium;

(3) according to the invention, the lignin fiber-based urea formaldehyde foam culture substrate is prepared by adding starch and acrylic acid, the starch and the acrylic acid react to generate starch super absorbent resin, the super absorbent resin is a hydrophilic high polymer with a three-dimensional space network structure, the water absorption of the super absorbent resin comprises physical adsorption and chemical adsorption, the physical adsorption means that the super absorbent resin absorbs water through a capillary tube, the water escapes under pressure, the chemical adsorption means that hydrophilic groups in the super absorbent resin firmly adsorb the water through chemical bonds, the adsorption capacity of the super absorbent resin is very strong, and the water cannot escape even under higher pressure, so that the water retention capacity of the culture substrate is effectively improved.

Detailed Description

Respectively weighing 50-60 parts of sawdust, 20-24 parts of sodium hydroxide and 200-240 parts of deionized water according to parts by weight, adding the sodium hydroxide into the deionized water, stirring at a rotation speed of 180-200 r/min for 10-20 min at normal temperature to obtain a sodium hydroxide solution, adding the sawdust into the sodium hydroxide solution, stirring at a rotation speed of 240-280 r/min for 40-60 min under a water bath condition of 80-90 ℃ to obtain a sawdust suspension, placing the sawdust suspension in an ultrasonic dispersion machine, ultrasonically oscillating at a power of 300-400W for 20-30 min at normal temperature, filtering, taking filter residues, washing the filter residues to be neutral by using the deionized water, drying in an oven at 60-80 ℃ for 1-2 h to obtain lignin fibers, placing the lignin fibers in a grinding machine, and grinding at a rotation speed of 200-240 r/min for 1-2 h at normal temperature to obtain fiber lignin powder; then respectively weighing 100-120 parts by weight of 30% by mass of formaldehyde, 50-60 parts by weight of urea and 5-6 parts by weight of melamine, adding 2/3 parts by weight of urea and melamine into formaldehyde, dropwise adding 1% by mass of ammonia water to adjust the pH value to 7.4-7.8, stirring and reacting for 1-2 h at the rotating speed of 200-240 r/min under the water bath condition of 70-80 ℃ to obtain reaction liquid, adding the residual 1/3 urea into the reaction liquid, dropwise adding 10% by mass of formic acid to adjust the pH value to 5.2-5.6, reacting at 30-40 ℃ in a water bath condition at 80-90 ℃, then preserving heat for 1-2 hours in a water bath condition at 40-50 ℃ to obtain a reaction liquid, cooling the reaction liquid to room temperature, dropwise adding a sodium hydroxide solution with the mass fraction of 10% to adjust the pH to be neutral, and stirring at the rotation speed of 300-400 r/min for 10-20 minutes at room temperature to obtain a urea-formaldehyde resin solution; then respectively weighing 40-60 parts of lignin fiber, 80-120 parts of urea-formaldehyde resin solution, 20-30 parts of corn starch, 16-24 parts of acrylic acid, 28-42 parts of soybean protein powder, 8-12 parts of cane sugar, 10-15 parts of carboxymethyl cellulose, 6-9 parts of chitosan, 0.2-0.3 part of ammonium persulfate, 4-6 parts of glycerol and 80-120 parts of deionized water, adding the corn starch into the deionized water, stirring at the rotating speed of 200-240 r/min for 10-16 min at normal temperature to obtain starch solution, adding lignin fiber powder into the starch solution, stirring at the rotating speed of 600-800 r/min for 20-30 min at normal temperature, then placing the starch solution into an ultrasonic dispersion machine, ultrasonically dispersing at the power of 400-500W for 20-30 min at normal temperature to obtain mixed dispersion liquid, adding the urea-formaldehyde resin solution, the acrylic acid, the ammonium persulfate and the glycerol into the mixed dispersion liquid, stirring at the rotating speed of 400-500 r/min for 30-40 min at normal temperature, and (3) obtaining a mixed system, adding the soybean protein powder, the sucrose, the carboxymethyl cellulose and the chitosan into the mixed system, placing the mixed system in a high-shear emulsifying machine, stirring the mixture for 2 to 4 hours at the normal temperature at the rotating speed of 10000 to 12000r/min to obtain a foaming system, placing the foaming system in a drying oven at the temperature of 70 to 80 ℃ for drying for 8 to 10 hours, and cooling the foaming system at the normal temperature to obtain the lignin fiber-based urea formaldehyde foam culture substrate.

Example 1

Respectively weighing 50 parts of wood chips, 20 parts of sodium hydroxide and 200 parts of deionized water according to parts by weight, adding the sodium hydroxide into the deionized water, stirring at a rotation speed of 180r/min for 10min at normal temperature to obtain a sodium hydroxide solution, adding the wood chips into the sodium hydroxide solution, stirring at a rotation speed of 240r/min for 40min under a water bath condition of 80 ℃ to obtain a wood chip suspension, placing the wood chip suspension in an ultrasonic dispersion machine, ultrasonically oscillating at a power of 300W for 20min at normal temperature, filtering, taking filter residues, washing the filter residues to be neutral by using the deionized water, placing the filter residues in a drying oven at 60 ℃ for drying for 1h to obtain lignin fibers, placing the lignin fibers in a grinding machine, and grinding at a rotation speed of 200r/min for 1h at normal temperature to obtain lignin fiber powder; weighing 100 parts by weight of 30% formaldehyde, 50 parts by weight of urea and 5 parts by weight of melamine, adding 2/3 parts by weight of urea and melamine into formaldehyde, dropwise adding 1% by weight of ammonia water to adjust the pH value to 7.4-7.8, stirring and reacting for 1h at a rotating speed of 200r/min under a water bath condition of 70 ℃ to obtain a reaction solution, adding the rest 1/3 parts by weight of urea into the reaction solution, dropwise adding 10% by weight of formic acid to adjust the pH value to 5.2, reacting for 30 ℃ under a water bath condition of 80 ℃, then placing in a water bath condition of 40 ℃ to keep the temperature for 1h to obtain a reaction solution, cooling the reaction solution to room temperature, dropwise adding 10% by weight of sodium hydroxide solution to adjust the pH value to neutral, and stirring for 10min at a rotating speed of 300r/min at normal temperature to obtain a urea-formaldehyde resin solution; respectively weighing 40 parts by weight of lignin fiber, 80 parts by weight of urea-formaldehyde resin solution, 20 parts by weight of corn starch, 16 parts by weight of acrylic acid, 28 parts by weight of soybean protein powder, 8 parts by weight of sucrose, 10 parts by weight of carboxymethyl cellulose, 6 parts by weight of chitosan, 0.2 part by weight of ammonium persulfate, 4 parts by weight of glycerol and 80 parts by weight of deionized water, adding the corn starch into the deionized water, stirring at the rotating speed of 200r/min for 10min at normal temperature to obtain starch solution, adding lignin fiber powder into the starch solution, stirring at the rotating speed of 600r/min for 20min at normal temperature, placing the starch solution into an ultrasonic dispersion machine, ultrasonically dispersing at the power of 400W for 20min at normal temperature to obtain mixed dispersion liquid, adding the urea-formaldehyde resin solution, the acrylic acid, the ammonium persulfate and the glycerol into the mixed dispersion liquid, stirring at the rotating speed of 400r/min at normal temperature for 30min to obtain a mixed system, and adding, Adding chitosan into the mixed system, placing the mixed system in a high-shear emulsifying machine, stirring the mixed system for 2 hours at the normal temperature at the rotating speed of 10000r/min to obtain a foaming system, placing the foaming system in a drying oven at the temperature of 70 ℃ for drying for 8 hours, and cooling the foaming system at the normal temperature to obtain the lignin fiber-based urea formaldehyde foam culture substrate.

Example 2

Respectively weighing 55 parts of wood chips, 22 parts of sodium hydroxide and 220 parts of deionized water according to parts by weight, adding the sodium hydroxide into the deionized water, stirring at the rotation speed of 190r/min for 15min at normal temperature to obtain a sodium hydroxide solution, adding the wood chips into the sodium hydroxide solution, stirring at the rotation speed of 260r/min for 50min under the condition of 85 ℃ water bath to obtain a wood chip suspension, placing the wood chip suspension in an ultrasonic dispersion machine, ultrasonically oscillating at the power of 350W for 25min at normal temperature, filtering, taking filter residues, washing with the deionized water to be neutral, placing in a 70 ℃ drying oven for drying for 1.5h to obtain lignin fibers, placing the lignin fibers in a grinding machine, and grinding at the rotation speed of 220r/min for 1.5h at normal temperature to obtain lignin fiber powder; respectively weighing 110 parts by weight of 30% formaldehyde, 55 parts by weight of urea and 5.5 parts by weight of melamine, adding 2/3 parts by weight of urea and melamine into formaldehyde, dropwise adding 1% by weight of ammonia water to adjust the pH value to 7.6, stirring and reacting for 1.5h at the rotating speed of 220r/min under the condition of 75 ℃ water bath to obtain a reaction solution, adding the rest 1/3 parts by weight of urea into the reaction solution, dropwise adding 10% by weight of formic acid to adjust the pH value to 5.4, reacting for 35 ℃ under the condition of 85 ℃ water bath, then placing in the condition of 45 ℃ water bath to keep the temperature for 1.5h to obtain a reaction solution, cooling the reaction solution to room temperature, dropwise adding 10% by weight of sodium hydroxide solution to adjust the pH value to be neutral, and stirring for 15min at the rotating speed of 350r/min under the room temperature to obtain a urea-formaldehyde resin solution; respectively weighing 50 parts by weight of lignin fiber, 100 parts by weight of urea-formaldehyde resin solution, 25 parts by weight of corn starch, 20 parts by weight of acrylic acid, 35 parts by weight of soybean protein powder, 10 parts by weight of sucrose, 11 parts by weight of carboxymethyl cellulose, 7 parts by weight of chitosan, 0.25 part by weight of ammonium persulfate, 5 parts by weight of glycerol and 100 parts by weight of deionized water, adding the corn starch into the deionized water, stirring at 220r/min for 13min at normal temperature to obtain starch solution, adding lignin fiber powder into the starch solution, stirring at 700r/min for 25min at normal temperature, placing the starch solution into an ultrasonic dispersion machine, ultrasonically dispersing at the normal temperature for 25min with the power of 450W to obtain mixed dispersion liquid, adding the urea-formaldehyde resin solution, the acrylic acid, the ammonium persulfate and the glycerol into the mixed dispersion liquid, stirring at the normal temperature for 35min with the rotation speed of 450r/min to obtain a mixed system, and adding the soybean protein powder, the, Adding chitosan into the mixed system, placing the mixed system in a high-shear emulsifying machine, stirring the mixed system for 3 hours at the normal temperature at the rotating speed of 11000r/min to obtain a foaming system, placing the foaming system in a drying oven at the temperature of 75 ℃ for drying for 9 hours, and cooling the foaming system at the normal temperature to obtain the lignin fiber-based urea formaldehyde foam culture substrate.

Example 3

Weighing 60 parts of wood chips, 24 parts of sodium hydroxide and 240 parts of deionized water respectively according to parts by weight, adding the sodium hydroxide into the deionized water, stirring at the rotation speed of 200r/min for 20min at normal temperature to obtain a sodium hydroxide solution, adding the wood chips into the sodium hydroxide solution, stirring at the rotation speed of 280r/min for 60min under the condition of 90 ℃ water bath to obtain a wood chip suspension, placing the wood chip suspension in an ultrasonic dispersion machine, ultrasonically oscillating at the power of 400W for 30min at normal temperature, filtering, taking filter residues, washing with the deionized water to be neutral, placing in an oven at 80 ℃ for drying for 2h to obtain lignin fibers, placing the lignin fibers in a grinding machine, and grinding at the rotation speed of 240r/min for 2h at normal temperature to obtain lignin fiber powder; respectively weighing 120 parts by weight of 30% by mass of formaldehyde, 60 parts by weight of urea and 6 parts by weight of melamine, adding 2/3 parts by weight of urea and melamine into the formaldehyde, dropwise adding 1% by mass of ammonia water to adjust the pH value to 7.8, stirring and reacting for 2 hours at a rotating speed of 240r/min under a water bath condition of 80 ℃ to obtain a reaction solution, adding the rest 1/3 parts by weight of urea into the reaction solution, dropwise adding 10% by mass of formic acid to adjust the pH value to 5.6, reacting for 40 ℃ under a water bath condition of 90 ℃, preserving heat for 2 hours under a water bath condition of 50 ℃ to obtain a reaction solution, cooling the reaction solution to room temperature, dropwise adding 10% by mass of sodium hydroxide solution to adjust the pH value to be neutral, and stirring for 20 minutes at a rotating speed of 400r/min under the room temperature to obtain a urea-formaldehyde resin solution; respectively weighing 60 parts by weight of lignin fiber, 120 parts by weight of urea-formaldehyde resin solution, 30 parts by weight of corn starch, 24 parts by weight of acrylic acid, 42 parts by weight of soybean protein powder, 12 parts by weight of sucrose, 15 parts by weight of carboxymethyl cellulose, 9 parts by weight of chitosan, 0.3 part by weight of ammonium persulfate, 6 parts by weight of glycerol and 120 parts by weight of deionized water, adding the corn starch into the deionized water, stirring at the normal temperature for 16min at the rotating speed of 240r/min to obtain starch solution, adding lignin fiber powder into the starch solution, stirring at the normal temperature for 30min at the rotating speed of 800r/min, placing the starch solution into an ultrasonic dispersion machine, ultrasonically dispersing at the normal temperature for 30min at the power of 500W to obtain mixed dispersion liquid, adding the urea-formaldehyde resin solution, the acrylic acid, the ammonium persulfate and the glycerol into the mixed dispersion liquid, stirring at the normal temperature for 40min at the rotating speed of 500r/min to obtain a mixed, Adding chitosan into the mixed system, placing the mixed system in a high-shear emulsifying machine, stirring the mixed system for 4 hours at the normal temperature at the rotating speed of 12000r/min to obtain a foaming system, placing the foaming system in an oven at the temperature of 80 ℃ for drying for 10 hours, and cooling the foaming system at the normal temperature to obtain the lignin fiber-based urea formaldehyde foam culture substrate.

The performance of the lignin fiber urea aldehyde foam culture substrate prepared by the invention and the commercial lignin culture substrate is detected, and the specific detection results are shown in the following table 1.

The test method comprises the following steps:

the lignin fiber urea aldehyde foam culture medium and the commercial lignin culture medium prepared by the invention are subjected to field tests. The test grass seeds are tall fescue, variety Ailam, the seeding rate is 30g/m²。

Water absorption rate determination method: adopting a fiber cement product experiment method (national standard GB/T7019-1197 of the people's republic of China), drying the matrix at constant temperature for 24h (measuring once at intervals of not less than 2h until the difference between the two previous weighing times is less than 0.1 percent), cooling the matrix to room temperature in a drier, and weighing (G1); the substrate was put in water at 10 ℃ or higher for 24 hours until the water level was higher than the substrate, the foam was taken out of the water, and the substrate was immediately weighed after carefully wiping off the water attached to the surface of the substrate with a wet towel (G2).

Water absorption = (G2-G1)/G1X 100%

Testing of water retention:

the test method comprises the following steps: obliquely inserting the sample into a container containing water, enabling the sample to be 10cm below the liquid level, moving out after 30min, hanging the sample for 2min without tension, flatly laying the sample on a steel wire mesh, weighing after 60min, repeating for 3 times, averaging until the weight of the two times is almost unchanged, namely the moisture absorption of the matrix material is saturated, and recording the weight. The substrate was laid flat on the film and thereafter weighed 1 time every 1h and data was recorded until the data was essentially unchanged for both recordings. Before each weighing, water is drained along the plastic film.

The water retention rate calculation formula is as follows: water retention = Wi/Wo × 100%

In the formula: wi denotes the mass of the substrate at the time of weighing at the ith hour Wo denotes the saturated wet weight of the substrate.

Germination rate:

the indoor germination test was carried out in an illumination incubator at 25 ℃ and the germination rate of seeds was measured at 10d after sowing and the plant height was measured at 20d after sowing.

Testing the lawn coverage:

the coverage is an important index for measuring the growth speed of the lawn grass and the lawn use performance, is the reflection of the growth speed of the lawn grass under the natural environment condition, and is the proportion of the vertical projection area of the lawn plants in unit area to the land area.

TABLE 1 characterization of lignin fiber-based Urea-formaldehyde foam culture substrate Properties

As shown in Table 1, the lignin fiber urea formaldehyde foam cultivation medium prepared by the invention has the advantages of extremely high water absorption rate, excellent water retention performance, high germination rate, uniform plant height and large coverage.

Claims

1. A preparation method of a lignin fiber-based urea formaldehyde foam culture medium is characterized by comprising the following specific preparation steps:

2. The preparation method of the lignocellulose-based urea formaldehyde foam culture medium according to claim 1, wherein the weight parts of the lignin fibers, the urea formaldehyde resin solution, the corn starch, the acrylic acid, the soybean protein powder, the sucrose, the carboxymethyl cellulose, the chitosan, the ammonium persulfate, the glycerol and the deionized water are 40-60 parts of the lignin fibers, 80-120 parts of the urea formaldehyde resin solution, 20-30 parts of the corn starch, 16-24 parts of the acrylic acid, 28-42 parts of the soybean protein powder, 8-12 parts of the sucrose, 10-15 parts of the carboxymethyl cellulose, 6-9 parts of the chitosan, 0.2-0.3 part of the ammonium persulfate, 4-6 parts of the glycerol and 80-120 parts of the deionized water.

3. The method for preparing the lignin fiber-based urea formaldehyde foam culture medium according to claim 1, wherein the power of the ultrasonic dispersion in the step (2) is 400-500W.

4. The preparation method of the lignin fiber-based urea formaldehyde foam culture medium according to claim 1, wherein the specific preparation steps of the lignin fiber powder in the step (2) are as follows:

5. The preparation method of the lignocellulose-based urea formaldehyde foam cultivation medium as claimed in claim 4, wherein the wood chips, the sodium hydroxide and the deionized water are 50-60 parts by weight, 20-24 parts by weight and 200-240 parts by weight.

6. The preparation method of the lignin fiber-based urea formaldehyde foam culture medium according to claim 4, wherein the power of the ultrasonic oscillation in the step (3) is 300-400W.

7. The preparation method of the lignin fiber-based urea formaldehyde foam culture medium according to claim 1, wherein the specific preparation steps of the urea formaldehyde resin solution in the step (3) are as follows:

8. The preparation method of the lignin fiber-based urea formaldehyde foam culture medium according to claim 7, wherein the formaldehyde, the urea and the melamine are 100-120 parts by weight of 30% formaldehyde, 50-60 parts by weight of urea and 5-6 parts by weight of melamine.

9. The method for preparing a lignocellulosic urea formaldehyde foam culture medium as claimed in claim 7, wherein the pH adjustment in step (1) is 1% by mass of ammonia water.

10. The method for preparing a lignocellulosic urea formaldehyde foam culture medium as claimed in claim 7, wherein the pH adjustment in step (2) is 10% formic acid by mass.