Biochar seed gel for vegetation restoration in saline-alkali land, preparation method therefor and use thereof

Abstract

The present invention belongs to the technical field of vegetation restoration, and provides a biochar seed gel for vegetation restoration in saline-alkali land, a preparation method therefor and the use thereof. The biochar seed gel in the present invention comprises: a water-retaining gel, effective nutritional components and a structural stabilizer, wherein the water-retaining gel is polyacrylamide, the effective nutritional components comprise Bacillus subtilis inoculant, brassinolide, chitosan oligosaccharide, polyaspartic acid, and a compound fertilizer, and the structural stabilizer comprises biochar, clay, chitosan and saponin powder. In the present invention, the biochar seed gel forms a microenvironment on the surface of soil, which reduces threats of hypersaline environments to the soil, and the gel has a strong water retention capacity, which helps to keep water supply for seed and seedling growth, alleviating phenomena of water shortage caused by soil hardening.

Description

Biochar seed gel for saline-alkali land vegetation restoration and preparation method and application thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of vegetation restoration, and particularly relates to a biochar seed gel for saline-alkali land vegetation restoration and a preparation method and application thereof. BACKGROUND

[0002] Saline-alkali land refers to land containing high concentrations of salt and alkaline substances in the soil, which poses a serious threat to agricultural production and the ecological system, resulting in a significant decrease in crop yield. In a saline-alkali environment, high concentrations of soil salt ions cause soil compaction, leading to poor soil structure and decreased fertility; excessive soil salinity easily interferes with the acquisition and transport of plant nutrients, causing nutrient imbalance, reducing vegetation productivity, and further triggering the degradation of surrounding environmental ecological functions, seriously threatening local ecological environment safety. Vegetation restoration for saline-alkali land is currently the focus of saline-alkali land ecological restoration.

[0003] The expansion and breeding of vegetation seeds and propagules are key links in the restoration of saline-alkali land vegetation, especially for the most common annual plants in saline-alkali land, which must maintain similar vegetation size each year. After vegetation degradation, there is a lack of sufficient seed sources and suitable soil environments to support the establishment of the community in the next year, and seeds and seedlings need to be passively supplemented. Common vegetation restoration measures mainly include sowing, plant species breeding, and transplanting. Through the expansion and breeding of plant seeds and propagules, the survival rate of plants in saline-alkali land is effectively improved, thereby achieving the restoration of local vegetation communities. However, in the high-salt and drought stress environment of saline-alkali land, the growth and germination of vegetation are severely restricted, and even the colonization and growth of stress-tolerant plants are affected to some extent, which poses a great challenge to the ecological restoration of saline-alkali land. Therefore, developing low-cost and high-benefit ecological restoration technologies that adapt to the special stress environment of saline-alkali land is a key technical requirement that needs to be addressed.

[0004] Improved seed technology has been relatively mature in the field of agriculture, and seed coating technology is widely used to improve seed tolerance and survival rate. By treating the seed with a coating agent, the germination rate, growth rate, and stress tolerance of the seed are improved. With the continuous development of ecological restoration, in the face of insufficient natural germplasm resources and relatively low natural seed germination rate in stress environments, seed coating technology has been gradually introduced into the field of vegetation restoration. For this special stress environment of saline-alkali land, it is particularly important to improve and optimize seed coating technology, but related technologies are still lacking. Traditional coating technology is designed for farmland as the practice scene, but in saline-alkali land, high salt and drought limit the application of traditional coating technology, and it is necessary to specifically propose overcoming techniques. The requirements for the effect of coating materials, especially the salt reduction and water retention effect, are more stringent.

[0005] In addition, the addition of fungicides, insecticides and the like in the conventional agricultural coating technology is contrary to the principle of environmental friendliness, and excessive synthetic organic and inorganic compounds cause environmental pollution, leading to further degradation of the local fragile ecosystem. Therefore, in view of the requirements of low cost, no pollution, salt reduction and drought resistance, the present application is proposed.

[0006] SUMMARY

[0007] The present application aims to provide a biochar seed gel for saline-alkali soil vegetation restoration and its preparation method and application, which overcomes the high salt and drought stress environment of saline-alkali soil and improves seed germination rate and plant stress resistance.

[0008] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0009] The present application provides a biochar seed gel for saline-alkali soil vegetation restoration, which comprises the following raw materials: water-retaining gel, effective nutrient component and structure maintaining agent.

[0010] The water-retaining gel is polyacrylamide; the effective nutrient component comprises Bacillus subtilis agent, brassinolide, chitosan oligosaccharide, polyaspartic acid and compound fertilizer; and the structure maintaining agent comprises biochar, clay, chitosan and soap nut powder.

[0011] Preferably, the weight ratio of the water-retaining gel, effective nutrient component and structure maintaining agent is 1-10:1-5:1-10.

[0012] Preferably, the mass ratio of the Bacillus subtilis agent, brassinolide, chitosan oligosaccharide, polyaspartic acid and compound fertilizer is 3-5:1-2:5-10:1-2:3-5.

[0013] Preferably, the mass ratio of the biochar, clay, chitosan and soap nut powder is 15-30:50-70:5-10:1-3.

[0014] Preferably, the bacterial concentration of the Bacillus subtilis agent is 5x10 10 ~1x10 12 cfu / g; the compound fertilizer is high-phosphorus and high-potassium compound fertilizer; the biochar is reed biochar with a mesh size of not less than 200 meshes; and the clay is in-situ soil in an ecological restoration area, which is dried at 170-190 DEG C for 20-24 hours and has a mesh size of not less than 100 meshes.

[0015] The present application also provides a preparation method of the biochar seed gel, which comprises the following steps:

[0016] 1) mixing Bacillus subtilis agent, brassinolide, chitosan oligosaccharide, polyaspartic acid and compound fertilizer to obtain an effective nutrient component agent;

[0017] 2) mixing the biochar, clay, chitosan and soap powder to obtain a structure maintaining agent;

[0018] 3) mixing the water-retaining gel, structure maintaining agent and effective nutrient component agent to obtain a biochar seed gel.

[0019] Preferably, the biochar seed gel is stored in a sealed environment at 3-5℃.

[0020] The application also provides a use of the biochar seed gel in repairing vegetation in saline-alkali soil.

[0021] Preferably, the biochar seed gel is suitable for seeds of halophytes with a diameter of less than 5mm, and the halophytes include Suaeda salsa.

[0022] Preferably, the use comprises the following steps:

[0023] (1) mixing the seeds after seed soaking and germination with the biochar seed gel at a mass ratio of 1:3-5 to obtain a seed and gel mixture;

[0024] (2) adding water in an amount of 8-12 times the mass of the seed and gel mixture in step (1), and after standing for 20-28h, spraying on the saline-alkali soil. Beneficial effects:

[0025] In the biochar seed gel provided by the application, polyacrylamide (PAM) is a high-molecular water-absorbing material, has good solubility in water, can form solutions with different concentrations, and has high water-absorbing and adhesive properties. It serves as the main material of the water-retaining gel and mainly plays a role in water retention, thickening and fixation. By forming a gel, water retention and salt exclusion are achieved, and the purpose of seed water retention and salt stress resistance is achieved.

[0026] The Bacillus subtilis agent is a microbial agent, wherein Bacillus subtilis is the main strain, provides nutrients and growth-promoting substances for the life activities of the strain, plays a role in improving the soil environment; the strain forms an antagonistic relationship with some harmful microorganisms, reduces the population density of harmful microorganisms, and plays a role in resisting diseases; the gas produced by the physiological activities of the strain changes the soil structure to some extent, helps to break the hardening of saline-alkali soil, and plays a role in loosening the soil; the use of salt by the life activities of the strain effectively reduces the salt content of the soil, and plays a role in relieving salt stress.

[0027] Brassinolide is a new type of plant endogenous hormone, plays a role in promoting plant growth and relieving plant salt stress. Compared with traditional plant growth regulators, brassinolide has stronger water solubility, smaller dosage and weaker biological toxicity.

[0028] Chitosan oligosaccharide is a low molecular oligosaccharide with excellent water solubility. The effects of chitosan oligosaccharide on plant growth include promoting plant growth, enhancing disease resistance and improving environmental adaptability. Chitosan oligosaccharide helps to improve plant growth rate, reduce disease incidence, and enhance the survival ability of plants in adverse environmental conditions and yield stability through mechanisms such as regulating plant internal hormones, inducing defense responses, and enhancing stress resistance.

[0029] Polyaspartic acid (PASP) as a biological stimulant is beneficial to plant growth, mainly in promoting seed germination and root growth, improving plant water use efficiency, and enhancing plant nutrient absorption capacity, thereby promoting plant growth, enhancing stress resistance, and improving yield stability.

[0030] High phosphorus and potassium compound fertilizer can achieve artificial supplementation of various elements required during plant growth and development.

[0031] Reed biochar is a carbon material made from reed and other plant materials through high-temperature pyrolysis. It provides a carbon source for microbial agents, improves soil structure, increases soil organic matter content, and enhances soil fertility and water retention. At the same time, its porous structure changes the physical and chemical properties of the soil, promotes the growth of soil microbial communities by creating a suitable soil microenvironment, and adsorbs and fixes nutrients, reducing nutrient loss and achieving slow release of nutrients.

[0032] Clay is the original soil of the ecological restoration area, mainly serving to maintain the structure. Adding clay to the biochar seed gel increases its weight. Clay has strong water retention capacity, which can improve soil permeability and water retention, and provide certain inorganic substances required for plant growth. At the same time, the original soil ensures the adaptability of the biochar seed gel to the practice area, improving seedling survival rate.

[0033] Chitosan is a natural polymer material with good biocompatibility, biodegradability, and bioactivity, which plays a thickening role. At the same time, chitosan has certain water retention capacity, which is an effective supplement to improve water retention capacity.

[0034] Soap powder is a natural surfactant that can enhance the adhesion of the gel to the seed surface, thereby improving the mechanical properties of the biochar seed gel.

[0035] In this invention, the biochar seed gel creates a microenvironment on the soil surface, reducing the stress of high-salt soil conditions. The gel also has strong water retention capacity, helping to maintain moisture for seed and seedling growth and alleviating water shortage caused by soil compaction. Furthermore, the main raw materials of the biochar seed gel are mostly natural, which reduces the negative environmental effects during its use. In addition, the biochar seed gel is easy to prepare, the materials are readily available, and the cost is low. The gel is stored in solid form, facilitating storage and transportation. After being mixed with water, it is sprayed onto the surface to be repaired, resulting in high work efficiency and facilitating large-scale remediation projects. Attached Figure Description

[0036] Figure 1 shows a gel seed sample from Example 2;

[0037] Figure 2 shows the results of the seed germination experiment in Example 3. Detailed Implementation

[0038] This invention provides a biochar seed gel for vegetation restoration in saline-alkali land, comprising the following raw materials: a water-retaining gel, effective nutrients, and a structure-maintaining agent. The water-retaining gel is polyacrylamide; the effective nutrients include Bacillus subtilis inoculant, brassinolide, chitosan oligosaccharide, polyaspartic acid, and compound fertilizer; and the structure-maintaining agent includes biochar, clay, chitosan, and saponin powder.

[0039] In this invention, the weight ratio of the water-retaining gel, effective nutrients, and structure-maintaining agent is 1-10:1-5:1-10, more preferably 10:2.5:7; the mass ratio of the Bacillus subtilis inoculant, brassinolide, chitosan oligosaccharide, polyaspartic acid, and compound fertilizer is 3-5:1-2:5-10:1-2:3-5, more preferably 3:1:6:2:3; the mass ratio of the biochar, clay, chitosan, and saponin powder is 15-30:50-70:5-10:1-3, more preferably 20:60:8:2.

[0040] In this invention, the bacterial concentration of the Bacillus subtilis inoculant is 5 × 10⁻⁶. 10 ~1×10 12 cfu / g, further preferably 1×10 11 The compound fertilizer is a high-phosphorus-potassium compound fertilizer, more preferably a water-soluble compound fertilizer, with an NPK ratio of 12:33:21; the biochar is reed biochar, with a mesh size ≥200 mesh; the clay is in-situ soil from the ecological restoration area, dried at 170-190℃ for 20-24 hours, with a mesh size ≥100 mesh, more preferably dried at 180℃ for 24 hours.

[0041] This invention also provides a method for preparing biochar seed gel, comprising the following steps:

[0042] 1) mixing Bacillus subtilis inoculant, brassinolide, chitosan oligosaccharide, polyaspartic acid and compound fertilizer to obtain an effective nutrient component agent;

[0043] 2) mixing biochar, clay, chitosan and soapnut powder to obtain a structure maintenance agent;

[0044] 3) mixing water-retaining gel, structure maintenance agent and effective nutrient component agent to obtain a biochar seed gel.

[0045] In the present application, the biochar seed gel is stored in a sealed environment at 3-5℃, and is further preferably at 4℃.

[0046] The present application also provides an application of the biochar seed gel in repairing vegetation in saline-alkali soil.

[0047] In the present application, the biochar seed gel is suitable for halophytes with a seed diameter of <5mm, and is further preferably Suaeda salsa.

[0048] In the present application, the application comprises the following steps:

[0049] (1) mixing the seed after seed soaking and germination with the biochar seed gel at a mass ratio of 1:3-5 to obtain a seed and gel mixture;

[0050] (2) adding water in an amount of 8-12 times the mass of the seed and gel mixture in step (1), and after standing for 20-28h, spraying on the saline-alkali soil.

[0051] The mass ratio of the seed to the biochar seed gel is further preferably 1:4, the amount of water added is further preferably 10 times the mass of the seed and gel mixture, and the standing time is further preferably 24h.

[0052] The technical solutions provided by the present application will be described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0053] Example 1: Preparation of biochar seed gel

[0054] (1) Pretreatment of experimental materials

[0055] The clay collected from the soil to be repaired was dried at 180℃ in an oven for 24h, and after cooling to 25℃, it was ground and pulverized for 15min, sieved, and the part with a clay mesh size ≥100 was retained;

[0056] The reed biochar was ground and pulverized for 15min, sieved, and the part with a mesh size ≥200 was retained.

[0057] (2) Preparation of effective nutrient component agent

[0058] Mix Bacillus subtilis inoculant, brassinolide, chitosan oligosaccharide, polyaspartic acid, and high-phosphorus potassium compound fertilizer in a mass ratio of 3:1:6:2:3 and stir for 20 min until uniform, to obtain the effective nutrient ingredient agent.

[0059] (3) Preparation of the structure maintenance agent

[0060] Mix reed biochar, clay, chitosan, and soap powder in a mass ratio of 10:30:4:1 and stir in a blender (550 W) for 20 min until uniform, to obtain the structure maintenance agent.

[0061] (4) Preparation of the biochar seed gel

[0062] Mix the water-retention gel, the effective nutrient ingredient agent, and the structure maintenance agent in a mass ratio of 10:2.5:7, and store the prepared biochar seed gel in a 4℃ environment under seal.

[0063] Example 2: Mixing of the seed and the biochar seed gel

[0064] In this example, Suaeda salsa (L.) Pall. is used as the selected implementation object.

[0065] 1) After the collected Suaeda salsa (L.) Pall. seeds are naturally air-dried, remove the dust and straw, sieve, and retain the seeds with a mesh size of 10-40 mesh.

[0066] 2) Rinse the Suaeda salsa (L.) Pall. seeds with 0.1% potassium permanganate solution, rinse for 3 min, then rinse with deionized water for 3 times, and soak the seeds in distilled water at 25℃ for 24 h for germination.

[0067] 3) Mix the soaked and germinated seeds with the biochar seed gel prepared in Example 1 in a mass ratio of 5:1, to obtain the seed and gel mixture, and the mixed state is shown in Fig. 1. In Fig. 1, the left image is the seed and gel mixture placed in a beaker, and the right image is a close-up of the seed and gel mixture, with the green seeds being Suaeda salsa (L.) Pall. seeds.

[0068] Example 3: Germination experiment of the seed under salt stress

[0069] Take the Suaeda salsa (L.) Pall. seeds with full grains, set up two treatments, the control group is the Suaeda salsa (L.) Pall. seeds treated by air selection, sieving, and germination (according to steps 1)-2) in Example 2) without mixing with the biochar seed gel, and the experimental group is the Suaeda salsa (L.) Pall. seeds mixed with the biochar seed gel (prepared according to the complete process in Example 2), with 9 parallel treatments in each group, and 100 (about 0.1 g) Suaeda salsa (L.) Pall. seeds in each parallel treatment. The experiment is carried out indoors, with an indoor temperature of 20℃±2℃ and uniform light throughout the day.

[0070] The natural slightly dry soil (from the north shore of the Yellow River Delta National Nature Reserve) is filled into a 9 cm diameter nutrient pot, and the soil layer is 6 cm thick. The experimental group is added with 10 times the mass of the seed and gel mixture, and after standing for 24 h, it is stirred evenly to form a turbid solution, which is sprayed onto the soil surface by a special instrument. The control group is added with water to the same volume as the experimental group solution, and then sprayed onto the soil surface.

[0071] At 12 o'clock noon every day, 9 groups are irrigated with different salinity salt water 10 mL (a total of 0 ppt, 2 ppt, 4 ppt, 8 ppt, 12 ppt, 16 ppt, 20 ppt, 24 ppt, 28 ppt nine salinity gradients), and the number of germinations is recorded at 4 o'clock in the afternoon. Germination is considered to be the emergence, and continuous culture is carried out for 8 days.

[0072] The results are shown in FIG. 2, and the test results show that under natural conditions, the seed germination rate decreases with the increase of salinity; the biochar seed gel breaks this rule, and the germination rate increases with the increase of salinity, and the germination rate is higher than that of ordinary seeds in an environment with a salinity of >12 ppt, and a relatively high germination rate level can be maintained. It is proved that in the high-salt and drought stress environment of saline-alkali soil, the gel has a promoting effect on seed germination.

[0073] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A biochar seed gel for saline and alkaline land vegetation restoration, characterized in that, The raw materials include water-retaining gel, effective nutrient component and structure maintaining agent; The water-retaining gel is polyacrylamide; The effective nutrient component includes bacillus subtilis agent, brassinolide, chitooligosaccharide, polyaspartic acid and compound fertilizer; The structure maintaining agent includes biochar, clay, chitosan and soapnut powder.

2. The biochar seed gel of claim 1, wherein, The weight ratio of the water-retaining gel, effective nutrient component and structure maintaining agent is 1-10:1-5:1-10.

3. The biochar seed gel of claim 2, wherein, The mass ratio of the bacillus subtilis agent, brassinolide, chitooligosaccharide, polyaspartic acid and compound fertilizer is 3-5:1-2:5-10:1-2:3-5.

4. The biochar seed gel of claim 3, wherein, The mass ratio of the biochar, clay, chitosan and soapnut powder is 15-30:50-70:5-10:1-3.

5. The biochar seed gel of claim 4, wherein, The bacterial concentration of the Bacillus subtilis bacterial agent is 5 x 10 10 ~ 1 x 10 12 cfu / g; The compound fertilizer is high-phosphorus and high-potassium compound fertilizer. The biochar is reed biochar, and the mesh number is ≥200 mesh. The clay is in-situ soil in ecological restoration area, dried at 170-190℃ for 20-24h, and the mesh number is ≥100 mesh.

6. A method of producing a biochar seed gel as claimed in claims 1 to 5, characterised by, The method comprises the following steps: 1) mixing bacillus subtilis agent, brassinolide, chitooligosaccharide, polyaspartic acid and compound fertilizer to obtain effective nutrient component agent; 2) mixing biochar, clay, chitosan and soapnut powder to obtain structure maintaining agent; 3) mixing water-retaining gel, structure maintaining agent and effective nutrient component agent to obtain biochar seed gel.

7. The production method according to claim 6, wherein The biochar seed gel is stored in a sealed environment at 3-5℃.

8. Use of the biochar seed gel according to any one of claims 1-5 or prepared by the method of any one of claims 6-7 in restoring vegetation in saline-alkali land.

9. Use according to claim 8, wherein the compound is ###0002### The biochar seed gel is suitable for salt-tolerant plants with seed diameter <5mm.

10. The use according to claim 9, wherein the compound is ###0002### The method comprises the following steps: (1) mixing the seed after seed soaking and germination with biochar seed gel at a mass ratio of 1:3-5 to obtain seed and gel mixture; (2) adding water in an amount of 8-12 times the mass of the seed and gel mixture in step (1), and after standing for 20-28h, spraying on the saline-alkali land.

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