Hydrogel material for artificial restoration of black land and restoration method thereof

Abstract

The invention relates to the technical field of soil remediation, and discloses a hydrogel material for artificially remedying black land and a remediation method thereof.The hydrogel material for artificially remedying black land is prepared from, by weight, 50%-70% of polymer matrix, 5%-15% of multifunctional cross-linking agent, 15%-30% of nutrition slow-release agent and 1%-5% of biological active agent; the multifunctional cross-linking agent is used for enhancing the mechanical strength and stability of the hydrogel; the polymer matrix comprises one of sodium alginate, chitosan and a chitosan derivative; the nutrient sustained-release agent comprises main nutrient elements such as nitrogen, phosphorus and potassium required by plant growth, trace elements and a growth regulator. According to the artificial restoration method for the black land, by applying the specific hydrogel material, the physical and chemical properties of soil can be improved, healthy development of a soil ecosystem can be promoted, and effective technical support is provided for sustainable agricultural production.

Description

Technical Field

[0001] The present invention relates to the technical field of soil restoration, and in particular to a hydrogel material for artificially restoring black soil and a restoration method thereof. Background Art

[0002] As an extremely valuable natural resource, black soil has suffered from soil structure damage and fertility decline due to long-term cultivation, erosion and loss of organic matter. Existing restoration technologies mostly rely on chemical fertilizers and soil conditioners, which have problems such as high cost, environmental pollution and short-term restoration effects. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a hydrogel material for artificially repairing black soil and a repair method thereof.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A hydrogel material for artificially repairing black soil comprises the following raw materials in percentage by weight: 50-70% of a polymer matrix, 5-15% of a multifunctional cross-linking agent, 15-30% of a nutrient slow-release agent, and 1-5% of a bioactive agent.

[0006] Preferably, the multifunctional cross-linking agent is used to enhance the mechanical strength and stability of the hydrogel.

[0007] Preferably, the polymer matrix includes one of sodium alginate, chitosan, and chitosan derivatives, and has excellent water absorption and biocompatibility.

[0008] Preferably, the nutrient slow-release agent contains major nutrient elements required for plant growth, such as nitrogen, phosphorus, potassium, as well as trace elements and growth regulators.

[0009] Preferably, the bioactive agent includes microbial agents and organic matter, which are used to improve the physical, chemical and biological properties of the soil.

[0010] The above-mentioned method for repairing black soil with a hydrogel material comprises the following steps: mixing the hydrogel material with black soil, and then irrigating according to soil conditions.

[0011] Preferably, the mixing ratio of the hydrogel material to the black soil is (0.3-1):1.

[0012] Preferably, the irrigation amount is automatically adjusted according to soil moisture to keep soil moisture within an optimal plant growth range.

[0013] The beneficial effects of the present invention are:

[0014] 1. The hydrogel material proposed in the present invention has high water absorption and can significantly improve the drought resistance of the soil; the nutrient slow-release agent added to the hydrogel material can provide the nutrients required for plant growth and improve the utilization efficiency of fertilizers; the microbial agents and organic matter in the bioactive agents added to the hydrogel material help to improve the soil structure and increase soil biodiversity.

[0015] 2. The present invention provides an artificial restoration method for black soil. By applying specific hydrogel materials, it can not only improve the physical and chemical properties of the soil, but also promote the healthy development of the soil ecosystem, providing effective technical support for sustainable agricultural production. The restoration method is environmentally friendly, and the biodegradable hydrogel material reduces the impact of agricultural production on the environment. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0017] Example 1: Sodium alginate and chitosan are mixed in a predetermined mixing ratio (sodium alginate: chitosan = 70:30 weight ratio) under stirring, and added to deionized water, heated to 60°C, and stirred continuously until completely dissolved to form a uniform polymer solution. The multifunctional crosslinker is dissolved in water to form a crosslinker solution of a certain concentration for standby use. The heated polymer solution is slowly poured into the crosslinker solution, stirring while pouring, so that the polymer and the crosslinker are fully in contact to form a preliminary three-dimensional network structure. The mixing ratio and the amount of crosslinker are controlled to adjust the porosity and mechanical strength of the hydrogel. The initially formed hydrogel is left to stand at room temperature for 3 hours to enhance its stability and mechanical strength. The freeze-curing method can also be used to put the hydrogel in a refrigerator to promote further stabilization of its internal structure. During the hydrogel curing process, the nutrient sustained-release agent and the bioactive agent are evenly dispersed in the hydrogel to make it a part of the hydrogel to achieve a sustained-release effect of nutrition and bioactivity. Dissolve the biodegradable polymer matrix in water, add a multifunctional cross-linking agent to form a pre-gel solution, then add a nutrient slow-release agent and a soil conditioner, mix thoroughly, and solidify into hydrogel particles or blocks by physical or chemical methods. Dig trenches or holes on the black soil, mix the hydrogel material evenly in the soil at a certain ratio (3%), and irrigate in time to activate the water absorption and nutrient release functions of the hydrogel according to soil conditions and crop needs.

[0018] Example 2: Under stirring, sodium alginate is weighed according to a predetermined concentration of 1-2% w / v, slowly added to deionized water, and heated to 80°C under continuous stirring until the sodium alginate is completely dissolved to form a uniform polymer solution. Calcium chloride is dissolved in water at (1M) to form a crosslinker solution for standby use. The heated sodium alginate solution is cooled to room temperature under stirring, and then slowly added to the calcium chloride solution, stirring while adding, so that the sodium alginate and the calcium ions are fully in contact, and ionic crosslinking is formed by the calcium ions and the carboxyl groups in the sodium alginate, gradually forming a stable three-dimensional network structure. The initially formed hydrogel is allowed to stand at room temperature for a period of 1 hour to enhance its stability and mechanical strength and to increase the crosslinking density and stability of the hydrogel. During the curing process of the hydrogel, the bioactive substances and nutrients are evenly dispersed in the hydrogel to make them part of the hydrogel to achieve the sustained release effect of bioactivity and nutrition. As needed, the hydrogel is cut or shaped, for example, cut into particles or blocks of a specific size to facilitate uniform mixing and application in the soil. Dig trenches or holes on the black soil and evenly mix the hydrogel material in a certain proportion (5%) into the soil.

[0019] Example 3: In a stirring container, chitosan is weighed according to a predetermined concentration of 2% w / v, a small amount of a dilute hydrochloric acid solution with a concentration of 1% v / v is added to dissolve the chitosan, heated to 70°C, and stirred continuously until completely dissolved to form a uniform polymer solution. In another container, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide are mixed in water or a buffer solution in a stoichiometric ratio (1:1) to activate the crosslinking reaction. The activated crosslinker solution is slowly added to the chitosan solution, stirring while adding, so that the crosslinker forms covalent crosslinks with the amino groups in the chitosan, and gradually forms a stable three-dimensional network structure. The mixed solution after the reaction is allowed to stand at room temperature for 2 hours to enhance the stability and mechanical strength of the hydrogel. During the hydrogel curing process, the bioactive substances and nutrients are evenly dispersed in the hydrogel, making them part of the hydrogel, so as to achieve a sustained release effect of bioactivity and nutrition. Finally, an appropriate amount of alkaline solution (1M NaOH) is used to neutralize the excess acid in the hydrogel, and then the hydrogel is washed with deionized water several times to remove unreacted crosslinking agent and impurities. The hydrogel is cut or shaped as needed, such as into particles or blocks of a specific size, so as to facilitate uniform mixing and application in the soil. A trench or hole is dug on the black soil, and the hydrogel material is evenly mixed in the soil at a certain ratio (7%).

[0020] Example 4: Chitosan and sodium alginate are dissolved in a predetermined ratio (1:1) in an appropriate solvent (chitosan in dilute acid, sodium alginate in deionized water), heated and stirred until completely dissolved to form a uniform polymer solution. Mix the cross-linking enzyme with an appropriate amount of enzyme activator, adjust the pH to 7.0 and the temperature to 40°C. Slowly add the matrix solution to the enzyme solution, stirring while adding, so that the polymer matrix is ​​fully in contact with the enzyme, and covalent cross-linking bonds are formed through enzyme-catalyzed reactions, gradually constructing a three-dimensional network structure. The mixed solution is allowed to stand for a period of time under appropriate conditions to complete the cross-linking reaction and enhance the stability of the hydrogel. As needed, the hydrogel is cut or shaped, and the bioactive additive is evenly dispersed in the hydrogel during the hydrogel curing process or post-processing stage to achieve sustained release of bioactivity. Dig trenches or holes in the black soil, and mix the hydrogel material evenly in the soil at a certain ratio (10%).

[0021] Example 5: Sodium alginate and chitosan are dissolved in deionized water to form a uniform polymer solution. An appropriate amount (3wt%) of pH-sensitive crosslinker dopamine is added to the polymer solution. The crosslinker can form or break within a specific pH range, thereby adjusting the pore structure and release characteristics of the hydrogel. The pH-sensitive compound fertilizer is dissolved in an appropriate solvent and then added to the polymer solution to form a uniform solution. The pH value of the solution is adjusted to the activation pH of the crosslinker so that the crosslinker reacts with the polymer matrix to form a hydrogel with a three-dimensional network structure. The synthesized hydrogel is cured at room temperature for 3 hours to enhance its stability and mechanical strength. The hydrogel is cut or shaped. Ditch or dig a hole in the black soil, and the hydrogel material is evenly mixed into the soil in a certain proportion (6%).

[0022] The experimental fields were divided into five groups. Each group was subjected to soil remediation according to the black soil remediation method of Examples 1-5. After the soil remediation was completed, soybean crops were planted in the five groups of experimental fields, and the growth indicators of the soybean crops in the five groups of experimental fields were recorded. The recorded data are shown in Table 1:

[0023] Table 1

[0024] Technical Parameters Example 1 Example 2 Example 3 Example 4 Example 5 Porosity (%) 71.3 94.5 85.7 78.5 80.6 Water absorption (g / g) 12.1 45.8 39.1 18.1 25.3 Water retention (g / g) 6.3 18.2 15.4 9.1 12.0 Biomass added value 15 31 22 29 29 Root growth increment 31 37 25 26 33

[0025] The hydrogel material for artificially repairing black soil and the repair method thereof provided by the present invention can effectively improve the water retention capacity of the soil, increase the content of soil organic matter, and promote the activity of soil microorganisms, thereby achieving long-term improvement of soil structure and fertility.

[0026] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A hydrogel material for artificial restoration of black soil, It is characterized in that The invention comprises the following raw materials in weight percentage: 50-70% of polymer matrix, 5-15% of multifunctional cross-linking agent, 15-30% of nutrient sustained-release agent and 1-5% of bioactive agent.

2. A hydrogel material for artificial restoration of black soil according to claim 1, It is characterized in that The polymer matrix includes one of sodium alginate and chitosan.

3. The hydrogel material for artificial restoration of black soil according to claim 1, It is characterized in that The nutrient slow-release agent contains nitrogen, phosphorus and potassium elements.

4. The hydrogel material for artificial restoration of black soil according to claim 1, It is characterized in that The bioactive agents include microbial agents and organic matter.

5. A method for repairing black soil using a hydrogel material as claimed in any one of claims 1 to 4, It is characterized in that The following steps are involved: The hydrogel material was mixed with black earth soil and then irrigated according to soil conditions.

6. A method for repairing hydrogel materials for artificially repairing black soil according to claim 5, It is characterized in that The mixing ratio of the hydrogel material to the black soil is (0.3-1):

1.

7. The method for repairing the hydrogel material for artificially repairing black soil according to claim 5, It is characterized in that The irrigation amount is automatically adjusted according to soil moisture.