Water-soluble fertilizer for repairing degraded soil and preparation method thereof

Abstract

The invention discloses a water-soluble fertilizer for repairing degraded soil and a preparation method thereof, the water-soluble fertilizer comprises solvent water and solute components, and the solute components comprise 20%-40% of long-chain fatty acid, 10%-20% of humic acid, 10%-20% of water-soluble lignin, 4%-12% of an emulsifier, 5%-10% of a surfactant, 4%-15% of Penicillium spiniferum, 2%-6% of potassium silicate, 3%-8% of propolis and the like, and 8%-15% of sodium dodecyl benzene sulfonate. The long-chain fatty acid is prepared by saccharifying and coupling grease, then stirring and mixing the long-chain fatty acid with the water and the emulsifier at 40-50 DEG C, and slowly adding the water and the water-soluble lignin to generate an emulsion; and adding humic acid and a surfactant, stirring and cooling, adding penicillium spiniferum, potassium silicate, propolis and the like, and uniformly stirring to obtain the water-soluble fertilizer. After the water-soluble fertilizer is used in degraded soil, salt reduction, soil loosening and water seepage are fast, water and fertilizer are saved, and the water-soluble fertilizer is matched with nutrient elements to promote the increase of crop yield.

Description

Technical Field

[0001] The present invention is applied to the field of fertilizers, and is suitable for highly saline degraded soils such as saline-alkali land and compacted land, and specifically relates to a water-soluble fertilizer capable of repairing degraded soils. Background Art

[0002] There are two main reasons for the formation of high-salinity degraded soils such as saline-alkali land or compacted land. One is natural, such as some lands in Ningxia Hui Autonomous Region and Xinjiang Uygur Autonomous Region, and the other is caused by excessive fertilization, such as some lands in Shandong, Hainan, Yunnan, etc. Degraded soil affects crop survival and development due to excessive soluble salts (sodium ions) in the soil. When the soil salt content exceeds 0.1%, it will inhibit crop growth. The greater the solubility of salt, the stronger the ability of ions to penetrate crop cells, and the greater the harm to crops. Excessive soluble salts affect crop water absorption. Only when the concentration of crop cell fluid is twice that of soil solution can it continuously absorb water from the soil. Otherwise, physiological dehydration will occur and the crop will wilt. Because water absorption is affected, nutrient absorption is also hindered. Some alkaline salts directly poison and corrode crops, and also inhibit the effective transformation of nutrients by beneficial microorganisms. In addition to salt damage, there is also alkali damage, such as exchangeable sodium ions in the soil, which deteriorates soil properties and affects the respiration of crop roots and nutrient absorption. Strong alkaline Na2CO3 can also destroy various enzymes in the roots of crops, affecting metabolism, especially having a strong corrosive effect on young roots and fine buds. Strongly alkaline soil makes it difficult for crops to absorb nutrients such as calcium, manganese, phosphorus, iron, and boron, often resulting in the dual hazards of salt damage and alkali damage.

[0003] There are many patent applications for improvers or conditioning fertilizers for saline-alkali degraded soil, such as a saline-alkali land special biological improvement fertilizer and its preparation method with application number 2011100912530, a saline-alkali land soil conditioner with application number 2015103153465, a saline-alkali land soil improvement special fertilizer with application number 2017110226690 and its preparation method, an organic fertilizer with the effect of improving saline-alkali land with application number 2017110096610, and a saline-alkali land special fertilizer with application number 2017114108570. The above-mentioned fertilizers for improving saline-alkali land are all solid fertilizers, which need to be mixed and buried in the soil, which are inconvenient to use, and the soil improvement time is long, the effect is slow, and the efficiency is low.

[0004] Water-soluble fertilizer is a multi-component compound fertilizer that can be completely soluble in water. It can dissolve quickly in water and is easily absorbed by crops. It has a high absorption rate and is easy to use. It can be used in sprinkler irrigation, etc. to achieve water-fertilizer integration and save water, fertilizer and labor. There are also many patents for using water-soluble fertilizer to improve degraded soil, such as a liquid fertilizer for soil saline-alkali land conditioning and its preparation method with application number 2023106005741, including 100-150 parts of ammonia water, 60-80 parts of straw, 50-70 parts of humic acid, 35-55 parts of potassium dihydrogen phosphate, 30-40 parts of ammonium sulfate, 10-18 parts of ammonium nitrate, 10-16 parts of potassium chloride, 5-15 parts of nitrogen-fixing bacteria, 6-10 parts of phosphate-solubilizing bacteria, and 6-10 parts of protease. It can achieve the technical effects of eliminating soil compaction, maintaining soil microecological balance, and regulating soil pH. The application number is 2016109935691, a water-soluble fertilizer containing humic acid with soil loosening function and its preparation method, using agricultural soil loosening essence, i.e. high-quality polyacrylamide crystals, water-soluble humic acid, urea, monoammonium phosphate, potassium nitrate as raw materials, dissolving and chelating in a reactor to produce a water-soluble fertilizer containing macroelements, medium and trace elements, humic acid, and amino acids, which can break soil compaction, loosen soil, improve soil permeability, promote soil microbial activity, and enhance soil fertilizer and water penetration. The fertilizer combines organic and inorganic elements, macroelements and trace elements, and has balanced nutrition, improves soil, and improves nutrient utilization. The application number is 2022100749611, which is a kind of aqueous amino acid for loosening soil and neutralizing salt and alkali, and its preparation method, including 10-15% composite amino acid, 20-25% phosphaturia, 1-3% citric acid, 5-10% synergist, 3-5% composite water retainer, 1-5% nutritional supplement and 0.3-0.5% polyacrylamide. Composite amino acids are nutrients for microorganisms and plants, and are also very good organic acids. When applied to saline-alkali soil, the alkalinity of the soil is integrated, providing nutrients to microorganisms in the soil, allowing microorganisms to multiply and secrete organic acids, decomposing various salt ions and beneficial elements solidified in the soil, and improving the utilization rate of nutrients in the soil. Citric acid complexes the salt ions in the soil and brings the salt ions into the deep soil with irrigation water. At the same time, citric acid is easily degraded by microorganisms in the soil without residue, and is suitable for the improvement of saline-alkali soil. The composite water retainer can significantly improve the water holding capacity and porosity of the soil, and has a positive promoting effect on improving the physical properties of the soil; the water retainer can also be mixed with fertilizers to prepare water-retaining slow-release fertilizers. Polyacrylamide mainly passivates the reaction rate of uric acid phosphate and soil alkali, can loosen the soil at a deeper level and neutralize salt and alkali. It can quickly replenish the fertility of the soil with a variety of inorganic nutrients and complex amino acids. After being mixed and matured with sandy soil through plowing and rotary tillage, it can significantly improve soil productivity.

[0005] In the above applications, although the soil was improved by various methods such as loosening agents, humic acid, water-retaining agents, amino acids, etc., the soil was not improved by using salt fixation, that is, by solidifying sodium ions to improve the soil. Summary of the invention

[0006] The technical problem solved by the present invention is to provide a water-soluble fertilizer for repairing degraded soil, which can improve and repair saline-alkali degraded soil from multiple angles such as improving water permeability, solidifying sodium ions, breaking up compaction, loosening soil, and providing beneficial bacteria.

[0007] The technical solution adopted by the present invention is: the water-soluble fertilizer for repairing degraded soil includes solvent water and solute components, and the weight of water is 20% to 30% of the weight of the solute component. The weight percentage of the solute component is: 20% to 40% long-chain fatty acids, 10% to 20% humic acid, 10% to 20% water-soluble lignin, 4% to 12% emulsifier, 5% to 10% surfactant, 4% to 15% Penicillium spicate, and 2% to 6% potassium silicate. Long-chain fatty acids are used as salt-fixing agents and soil loosening agents; water-soluble lignin and humic acid can not only improve the pelleting, but also passivate sodium ions and reduce salt; emulsifiers and surfactants have the effect of increasing penetration and promoting oil-water fusion; Penicillium spicate is used as a salt-fixing agent and can also provide beneficial bacteria; potassium silicate mainly provides silicon for the growth and development of Penicillium spicate.

[0008] Furthermore, in order to strengthen the beneficial bacteria, the solute component also includes 3% to 8% of propolis. While protecting and nourishing the beneficial bacteria, propolis can also reduce the pH value of the soil and strengthen the function of improving the aggregate structure.

[0009] Furthermore, for degraded soil contaminated by carbendazim pesticides, sodium dodecylbenzene sulfonate has the most significant solubilizing effect on carbendazim and organic matter in the soil, and the solute component also includes 5% to 10% of sodium dodecylbenzene sulfonate.

[0010] Furthermore, the long-chain fatty acids are prepared from vegetable oil, and / or animal oil, and / or waste cooking oil through saccharification, emulsification, and coupling, and can also be purchased from outside.

[0011] Furthermore, the emulsifier is a vegetable oil emulsifier and / or an animal oil emulsifier, the vegetable oil emulsifier is castor oil polyoxyethylene ether, and the animal oil emulsifier is RU-70.

[0012] Furthermore, the surfactant is one or a combination of two or more of fatty alcohol polyoxyethylene ether, OP-10, and NP-10.

[0013] Furthermore, in order to provide the nutrients required for crop production, the water-soluble fertilizer contains nitrogen, phosphorus, potassium and trace nutrients.

[0014] The preparation method of the water-soluble fertilizer comprises the following steps: 1) preparation of long-chain fatty acids; 2) preparation of emulsion: stirring and mixing long-chain fatty acids, water, vegetable oil emulsifier or animal oil emulsifier at a temperature of 40 to 50°C for 0.5 to 1 hour, slowly adding water and water-soluble lignin, stirring and mixing to dissolve each other to form an emulsion; 3) preparation of water-soluble fertilizer: adding humic acid and surfactant to the emulsion, continuing to stir and cool; when the temperature drops below 32°C, adding Penicillium microcarpa, potassium silicate and propolis, stirring evenly to form a water-soluble fertilizer.

[0015] Furthermore, the method for preparing long-chain fatty acids in step 1) is as follows: adding vegetable oil, and / or animal oil, and / or waste oil, as well as saccharifying enzyme and amylase, into a reaction tank, stirring and heating to 80°C to 120°C, performing saccharification reaction to generate unsaturated fatty acids; cooling to 50°C to 70°C, adding hydrogen peroxide coupling agent, continuing stirring and heating to generate long-chain fatty acids. When animal oil is used, water can be added as a heat transfer medium.

[0016] Furthermore, sodium dodecylbenzene sulfonate is added in the aforementioned step 3) to become a water-soluble fertilizer for degraded soils contaminated by carbendazim pesticides, or one or more of urea, dipotassium hydrogen phosphate, calcium magnesium soluble fertilizer, and boron zinc soluble fertilizer are added in the aforementioned step 3) to become a water-soluble fertilizer containing nutrient elements. One or more of urea, dipotassium hydrogen phosphate, calcium magnesium soluble fertilizer, and boron zinc soluble fertilizer can also be added after step 3) and stirred evenly.

[0017] The beneficial effects of the present invention are as follows: 1) Good salt fixation effect and fast salt reduction. The alkalinity of the surface soil can be significantly reduced within 3 to 5 days after use. 2) Fast soil loosening. Through wetting and expansion, the soil is quickly loosened and the compaction is broken to restore the normal aggregate structure. 3) Fast water infiltration allows water and fertilizer to infiltrate faster, reducing water and fertilizer runoff losses and evaporation losses, alleviating secondary salinization, and rebuilding water and gas channels. 4) Water and fertilizer saving. By accelerating water infiltration, promoting uniform distribution of water in the root layer soil, and extending water retention time, water and fertilizer saving can be achieved. 5) Combined with nitrogen, phosphorus, potassium nutrients and medium and trace elements, it promotes the increase of crop yields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a comparison of solid salt experiments; Figure 2 It is a comparison of soil samples before and after the use of water-soluble fertilizer in the same plot; Figure 3 It is a comparison of water infiltration capacity of soil samples from the same plot; Figure 4 It is a comparison of the use of water-soluble fertilizer and water in the same plot of soil sample; Figure 5 This is a comparison chart of the changing trends of soil moisture content in the same plot after drip irrigation of water-soluble fertilizer. DETAILED DESCRIPTION

[0019] The idea of ​​the invention to improve and restore degraded soil by fixing salt, loosening soil and increasing permeability is to improve the permeability of water-soluble fertilizers, which can quickly penetrate into compacted soil, use the wetting and swelling effect of water-soluble fertilizers to quickly loosen the soil, break up compaction, improve soil aggregate structure, and quickly migrate water-soluble surface soil salt to deep soil. The salt that has not migrated to the deep layer is solidified in organic matter or beneficial bacteria, and can also protect and nourish the beneficial bacteria. Degraded soil is improved and restored from multiple angles such as penetration and breaking up compaction, salt removal and fixing, improving aggregates, and providing beneficial bacteria. Example 1

[0020] Water-soluble fertilizer is in liquid form, including water and solute components, with water as solvent, and the added amount is 20% to 30% of the weight of the solute component. The solute components include: 20% to 40% long-chain fatty acids, 10% to 20% humic acid, 10% to 20% water-soluble lignin, 4% to 12% vegetable oil emulsifier or animal oil emulsifier, 5% to 10% surfactant, 4% to 15% Penicillium microcarpon, 2% to 6% potassium silicate, and 3% to 8% propolis. The above contents are weight percentages, accounting for the total weight of the solute.

[0021] As the main soil loosening and salt-fixing agent, long-chain fatty acids penetrate into compacted soil by wetting, expand and break soil compaction, make soil into particles or granules, improve soil permeability, make soil have multi-level pores, and increase soil water absorption capacity. Long-chain fatty acids have specific structural forms and sizes, and have the ability to resist microbial decomposition and fragmentation. After entering the soil, long-chain fatty acids will decompose to produce acidic substances, which is beneficial to lower the pH value of degraded soil. In addition, long-chain fatty acids can react with sodium ions to form fatty acid sodium, fix sodium ions, and serve as the main salt-fixing agent. When the content exceeds 40%, long-chain fatty acids will have a toxic effect on plant roots, combine with calcium, magnesium and other ions in the soil, form insoluble salts, and reduce effective nutrients in the soil. When the content is less than 20%, for highly saline degraded soils, the function of breaking compaction or fixing salt is not significant.

[0022] Humic acid is a high molecular polymer obtained by treating natural organic weak acid. It is water-soluble and can enhance organic matter, improve soil aggregate structure, and improve water and fertilizer retention capacity. It can also passivate sodium ions, reduce salt and soil pH. When the content exceeds 20%, the organic matter is too high, the soil structure is damaged, and it is easy for plants to produce anaerobic respiration and root rot. When the content is less than 10%, the effect of improving soil aggregate structure is reduced.

[0023] Water-soluble lignin is a high molecular organic matter, mainly used to improve the aggregate structure of soil as one of the soil loosening agents. Water-soluble lignin can be dissolved in water and evenly distributed in the soil with water to achieve uniform air permeability of the soil. Water-soluble lignin contains multiple rings of negatively charged groups and has a strong affinity for highly active metal ions (sodium ions) in the soil. It is used to activate phosphorus and zinc in the soil and complex sodium ions in soil water to assist in salt fixation. When the content exceeds 20%, it is easy for plants to produce anaerobic respiration. When it is less than 8%, the effect of improving the soil is not significant.

[0024] The main function of long-chain fatty acids is to loosen the soil and fix salts, and the main function of water-soluble lignin and humic acid is to improve the soil aggregate structure. The combined effect of the above three organic matter is stronger than the function of loosening the soil and improving the soil aggregate structure by using a single organic matter. Without producing side effects, it can largely achieve the function of loosening the soil and improving the soil aggregate structure.

[0025] Vegetable oil emulsifier or animal oil emulsifier is used as an emulsifier to achieve oil-water miscibility, and the above organic matter is formed into a water-soluble organic fertilizer. Vegetable oil emulsifier is a complex of various surfactants and adjuvants, non-ionic properties, good compatibility, colorless or yellow transparent viscous liquid, and good low temperature resistance. Vegetable oil emulsifier is soluble and transparent in vegetable oil, has good emulsification and dispersibility, has good emulsification effect on various vegetable oils such as rapeseed oil, soybean oil, peanut oil, etc., and can form a stable emulsion. In this embodiment, the vegetable oil emulsifier is preferably castor oil polyoxyethylene ether (CAS No. 61791-12-6). Under normal circumstances, the amount of vegetable oil emulsifier is 20% to 30% of the vegetable oil. After stirring evenly, water is slowly added thereto, and water is added while stirring quickly to obtain a vegetable oil emulsion. Animal oil emulsifier is soluble in animal oil and general organic solvents, dispersed in water, has good emulsification properties, and is used for the emulsification of animal oils, such as butter, lard, chicken oil, duck oil, etc. It is compounded by a variety of anionic and nonionic surfactants, with a pH value of 4.0-7.0 (1% aqueous solution). In this embodiment, the animal oil emulsifier is preferably RU-70 (product brand). Under normal circumstances, the amount of animal oil emulsifier is 20%-30% of the amount of animal oil. The emulsifier is added to the animal oil and heated to melt, and then warm water at 40℃-50℃ is added, the amount of water is about one time of the animal oil, and it is dissolved after being fully stirred.

[0026] Surfactants can reduce the surface tension of water, achieve rapid penetration of water-soluble organic fertilizers in the soil, and wash the surface salt to below the roots of crops through water, reduce the root salt content, and do not affect the development of plant roots. In addition, surfactants also have hydrophilic and lipophilic groups, which can be used as emulsifiers to assist the miscibility of oil and water. In this embodiment, the surfactant is preferably one or a combination of two of fatty alcohol polyoxyethylene ether (CAS No. 68131-39-5), OP-10 (alkylphenol polyoxyethylene ether), and NP-10 (alkylphenol polyoxyethylene ether). If the surfactant is used in large amounts or is not easily biodegradable, it will remain in the environment for a long time, which will affect the soil and water quality and have an adverse effect on the ecosystem; or it will destroy the physical structure of the soil and affect the growth of plants. Therefore, it is advisable to choose 5% to 10%.

[0027] As auxiliary agents, the above-mentioned emulsifier and surfactant have an important influence on the use performance of water-soluble fertilizer. The surfactant directly determines the penetration ability of water-soluble fertilizer in compacted soil, and the emulsifier directly determines the fusion ability of organic matter and water. In fact, the functions of the two are cross-linked, and the emulsifier also has the effect of surface activity, and the surfactant also has the effect of emulsification, but the two functions are different in strength. It should be noted that the above-mentioned emulsifier and surfactant have been successfully used in research and development and trial production, and the present embodiment does not exclude the use of other emulsifiers and surfactants.

[0028] Penicillium spicate is widely used in scientific research in the fields of microbiology and biotechnology. It is not widely used in organic water-soluble fertilizers. It belongs to beneficial bacteria. After breeding in the soil, it secretes plant production hormones and various enzymes to enhance the resistance of crops to some diseases, and also inhibits the growth of other pathogens. At the same time, it can produce organic acids, amino acids, polysaccharides, hormones and other substances that are beneficial to plant absorption and utilization during the growth and reproduction process. This embodiment uses salt water of appropriate concentration as a way to preserve Penicillium spicate, and Penicillium spicate is applied to the improvement and repair of saline-alkali compacted soil. During the growth and development of Penicillium spicate, it absorbs sodium ions and active silicon in the soil, generates cell walls and nuclear skeletons, and plays a role in salt fixation. In addition, humic acid also provides nutrition for the growth and development of Penicillium spicate. At the same time, Penicillium spicate accelerates the combination of humic acid and soil, and strengthens the function and effect of humic acid. The dosage of Penicillium spicate is 4% to 15%, and the upper limit is taken for high saline-alkali land, and the lower limit can be taken for soil that needs to be repaired and is not severely compacted.

[0029] Potassium silicate provides active silicon for the growth and development of Penicillium, promotes the growth and development of Penicillium, and strengthens the salt-fixing function of Penicillium. In addition, potassium silicate can also combine with water in the soil to form silica gel, which has the function of expanding the soil while providing silicon and assisting in loosening the soil. The dosage of potassium silicate is related to Penicillium, and increases or decreases with the increase or decrease of Penicillium.

[0030] Propolis contains a large amount of flavonoids, which have a significant inhibitory and killing effect on bacteria, fungi, and viruses in the soil. At the same time, it will not destroy beneficial bacteria and protects them. The acid compounds contained in propolis can lower the pH value in the soil, and amino acids provide nutrition for the growth of beneficial bacteria. In addition, propolis helps the soil form a colloid structure, strengthens the function of water-soluble lignin and humic acid to improve the soil aggregate structure, and can also form long chains with organic matter to prevent organic matter from being lost with water.

[0031] The combined use of Penicillium microsporum and potassium silicate promotes the growth and development of Penicillium microsporum in alkaline soil, strengthens the salt fixation effect, and also provides beneficial bacteria for the soil. Potassium silicate also has the function of loosening the soil and breaking up the compaction. The main function of propolis is to protect and nourish the beneficial bacteria, and it also plays a role in assisting organic matter to improve soil aggregates. For soils that do not strengthen the beneficial bacteria, propolis can be omitted.

[0032] In summary, the solute components of water-soluble fertilizers are selected and proportioned according to the functions of strengthening penetration, breaking compaction, fixing salts, improving granulation, and providing beneficial bacteria. Moreover, the selection of each component takes into account dual or multiple functions, as well as combined effects and functional enhancement. For example, long-chain fatty acids are used as both salt-fixing agents and soil loosening agents; Penicillium sphaerocephalum is used as both a salt-fixing agent and a beneficial bacteria; the combination of water-soluble lignin and humic acid can not only improve granulation, but also passivate sodium ions and reduce salt content; surfactants and emulsifiers have the functions of enhancing penetration and promoting the fusion of organic matter and water; potassium silicate has the function of assisting soil loosening while providing the silicon required for the growth and development of Penicillium sphaerocephalum; propolis can protect and nourish beneficial bacteria while also reducing soil pH and strengthening the function of improving granular structure.

[0033] The preparation method and steps of water-soluble fertilizer of the present invention are as follows: 1) Preparation of long-chain fatty acids. Pour vegetable oil and / or animal oil, such as rapeseed oil, soybean oil, peanut oil, butter, lard, chicken oil, duck oil, etc., into the reactor. Animal oil is usually solid at room temperature. When animal oil is used, an appropriate amount of water can be added. Water is used as a heat transfer medium, which is conducive to uniform heating of the animal oil and avoids overburning and gelatinization of the animal oil. Then stir and heat to 80℃~120℃. Since oil and water are insoluble, water evaporates at about 100℃, and only oil is left in the reactor. During the heating process, add an appropriate amount of saccharifying enzyme and amylase to make the vegetable oil and animal oil undergo saccharification reaction to generate unsaturated fatty acids. After about 24 hours, cool down to 50℃~70℃, add hydrogen peroxide as a coupling agent, continue stirring and heating, and after about 12 hours, long-chain fatty acids are generated.

[0034] In order to reduce costs, the present invention can use the filtered and cleaned waste cooking oil to replace part or all of the vegetable oil or animal oil, thereby turning waste cooking oil into treasure and providing another application scenario for waste cooking oil.

[0035] 2) Preparation of emulsion. Add long-chain fatty acids, water, vegetable oil emulsifier and / or animal oil emulsifier to the reaction tank. The structure of the reaction tank is shown in the previously applied patent "A reaction tank for water-soluble fertilizer" (application number 2024223132019). Stir and mix at a temperature of 40 to 50°C. After 0.5 to 1 hour, gradually and slowly add water and water-soluble lignin. To prevent excessive cooling, the water should be 40 to 50°C hot water and continue stirring. The water-soluble lignin is dissolved in water. Under the action of the emulsifier, the long-chain fatty acids and water are mixed and dissolved to form an emulsion.

[0036] 3) Preparation of water-soluble fertilizer. Add humic acid and surfactant to the emulsion, continue stirring, stop heating, and gradually cool down. When the temperature drops below 32°C, add Penicillium microcarpon and potassium silicate, as well as propolis, and stir evenly to make water-soluble fertilizer. Transport it to the packaging process through pipelines for bottling or barreling.

[0037] Since the preparation time of long-chain fatty acids is relatively long, multiple reactors need to be set up to coordinate with one reaction tank. In order to improve production efficiency, long-chain fatty acid finished products can also be purchased directly from outside.

[0038] The method of using the water-soluble fertilizer in this embodiment is: 0.5-1 kg is used for one mu of land, diluted with water, and the dilution concentration is not less than 300 times. It can be irrigated by drip irrigation, sprinkler irrigation, or watering, or by combining different irrigation methods. It is advisable to irrigate 2 or 3 times a year, and the degraded soil is repaired and the soil is significantly improved.

[0039] The beneficial effects produced by this embodiment are: 1) The salt fixation effect is obvious. Figure 1 The comparison photos of the salt fixation test are shown in the figure. The weight of salt added to the two vessels is the same. The left vessel is filled with a salt solution, and the right vessel is filled with a salt solution of a water-soluble fertilizer. The salt solution in the left vessel was heated in a microwave oven for 8 minutes, and all the water evaporated, but the salt crystals remained. The salt solution of the water-soluble fertilizer in the right vessel was heated in a microwave oven for 14 minutes, and after all the water evaporated, it became a colloidal semisolid, without salt crystals, and the salt fixation effect exceeded expectations. The water-soluble fertilizer of the present invention can quickly alleviate salt stress, and generally can significantly reduce the alkalinity of the surface soil 3 to 5 days after use.

[0040] 2) Fast soil loosening. It significantly improves the wettability of water, so that it can enter the ultra-fine soil pores that normal water cannot enter, and quickly loosens the soil and breaks up the compaction through wetting and expansion. The soil is no longer sticky and restores the normal aggregate structure, which has a better effect of retaining water and fertilizer. Figure 2The screenshot from the applicant's promotional video is a comparison of soil samples before and after the use of this embodiment on the same plot of land. The left side is the soil sample before use, and the right side is the soil sample after use. Figure 2 It can be seen that the size of the soil block in the left soil sample is significantly larger than that in the right soil sample, indicating that this embodiment has good soil loosening and compaction breaking functions. Figure 4 Also from the screenshot of the promotional video, in the 200g soil sample of the same plot, 60ml of water was added on the left, and 50ml of water and 10ml of the present embodiment (Zhishui Huanneng is the product name of the applicant, attached Figure 5 Similarly), the left side is muddy, and the right side is porous block, which shows that the present invention has significant functions of breaking the compaction and retaining water.

[0041] 3) Fast water infiltration. Allowing water-soluble fertilizers to infiltrate faster can not only reduce the runoff loss and evaporation loss of water-soluble fertilizers for water-repellent soils with salinized and compacted topsoil, but can also wash water-soluble sodium ions and other salts deep into the soil and below the roots of crops, thereby reducing secondary salinization and improving soil nutrient utilization. For soils with poor water permeability, long-term waterlogging is not conducive to the growth and development of the root system. Using this embodiment can rebuild the water vapor channel, improve water permeability, and increase air permeability. Figure 3 Also a screenshot from the applicant's promotional video, it is a comparative test of the water permeability of soil samples from the same plot of land. In both beakers, 50 ml of liquid was added to 200 ml of soil sample. The liquid added on the left was water, and the liquid added on the right was water-soluble fertilizer diluted with water. After 14 minutes, the water on the left had penetrated to about 110 ml, and there was still water on the surface; the diluted water on the right had penetrated to about 40 ml, and there was no diluted water on the surface. It can be seen that the permeability of the water-soluble fertilizer in this embodiment is nearly twice that of water.

[0042] 4) Save water and fertilizer. By accelerating water infiltration, promoting the uniform distribution of water in the root layer soil, and prolonging the water retention time, water runoff and evaporation loss can be reduced, thus saving water and fertilizer. Figure 5 This is a comparison chart of the moisture content change trend of the drip irrigation of the same plot, which is extracted from the applicant's promotional materials. Drip irrigation was carried out on a plot without crops on August 23, 2020, and soil moisture (water content) was continuously monitored from August 26 to September 7. The results showed that within a week, the drip irrigation scheme of 75% water + 0.1% of this embodiment almost reached the moisture content of 100% water irrigation, with obvious water-saving effect. Example 2

[0043] This embodiment is based on Example 1, and sodium dodecylbenzene sulfonate is added, and the added amount is 5% to 10% of the total weight of the solute. Sodium dodecylbenzene sulfonate is usually used as a surfactant. In addition, sodium dodecylbenzene sulfonate has good biodegradability and can reduce the harm to the soil. When sodium dodecylbenzene sulfonate is added, the surfactant in Example 1 should preferably be taken as the lower limit. Sodium dodecylbenzene sulfonate has the most significant solubilization effect on carbendazim and organic matter in the soil, and at the same time has a better leaching effect on the oxygen demand of dichromate, so it is suitable for the remediation of degraded soil contaminated by carbendazim pesticides.

[0044] During the preparation of this embodiment, sodium dodecylbenzene sulfonate is added together with a surfactant in the step of preparing the water-soluble fertilizer. Example 3

[0045] The water-soluble fertilizer in Example 1 strengthens and improves the degraded soil, but fails to provide the nutrients required for crop production. Based on the above example, this example can add urea, dipotassium hydrogen phosphate, etc. according to the user's requirements to prepare a water-soluble fertilizer containing nitrogen, phosphorus and potassium nutrients. The content of nitrogen, phosphorus and potassium in the water-soluble fertilizer is not lower than the national standard requirements, or is proportioned according to the user's requirements.

[0046] During the preparation of this embodiment, urea, dipotassium hydrogen phosphate, etc. are added during step 3) of preparing the water-soluble fertilizer, or they can be added after the preparation is completed. Example 4

[0047] This embodiment adds trace elements such as Ca, Mg, B, and Zn on the basis of embodiment 3. In step 3), when preparing the water-soluble fertilizer, or when the water-soluble fertilizer is prepared in embodiment 3, or after the preparation of embodiment 3, purchased calcium-magnesium soluble fertilizer, boron-zinc soluble fertilizer, etc. are added to prepare a water-soluble fertilizer containing trace elements. The content of trace elements in the water-soluble fertilizer can be set according to user requirements and should meet national standards.

[0048] The water-soluble fertilizer of this embodiment was tested in the experimental field of Handan Academy of Agricultural Sciences, and crops such as cotton, spring peanuts and summer corn were planted for experimental comparison. The yields of the three crops to which the water-soluble fertilizer of this embodiment was applied increased by 17%, 17.2% and 15.2%, respectively.

[0049] Under the premise of strengthening the penetration capacity of water-soluble fertilizers, the present invention improves saline-alkali soil from three aspects of salt fixation, soil loosening and providing beneficial bacteria. It is not only suitable for the restoration of high-salinity degraded soil, but also can be used to optimize soil structure and cooperate with nitrogen, phosphorus and potassium nutrients and medium and trace elements to promote the increase of crop yield.

Claims

1. A water-soluble fertilizer for repairing degraded soil, comprising solvent water and solute components, characterized in that: The weight percentages of the solute components are: 20% to 40% long-chain fatty acids, 10% to 20% humic acid, 10% to 20% water-soluble lignin, 4% to 12% emulsifier, 5% to 10% surfactant, 4% to 15% Penicillium microcarpa, and 2% to 6% potassium silicate.

2. A water-soluble fertilizer for repairing degraded soil according to claim 1, characterized in that: The solute component also includes 3% to 8% of propolis.

3. A water-soluble fertilizer for repairing degraded soil according to claim 2, characterized in that: The solute component also includes 5% to 10% of sodium dodecylbenzene sulfonate.

4. A water-soluble fertilizer for repairing degraded soil according to any one of claims 1 to 3, characterized in that: The long-chain fatty acid is prepared by saccharifying and coupling vegetable oil, and / or animal oil, and / or waste cooking oil.

5. A water-soluble fertilizer for repairing degraded soil according to any one of claims 1 to 3, characterized in that: The emulsifier is a vegetable oil emulsifier and / or an animal oil emulsifier. The vegetable oil emulsifier is castor oil polyoxyethylene ether, and the animal oil emulsifier is RU-70.

6. A water-soluble fertilizer for repairing degraded soil according to any one of claims 1 to 3, characterized in that: The surfactant is one or a combination of two or more of fatty alcohol polyoxyethylene ether, OP-10, and NP-10.

7. A water-soluble fertilizer for repairing degraded soil according to any one of claims 1 to 3, characterized in that: The water-soluble fertilizer contains nitrogen, phosphorus, potassium nutrient elements and medium and trace nutrient elements.

8. The method for preparing the water-soluble fertilizer according to claim 2, wherein the preparation steps include: 1) Preparation of long-chain fatty acids; 2) Preparation of emulsion: stir and mix long-chain fatty acids, water and emulsifier at a temperature of 40-50°C for 0.5h-1h, slowly add water and water-soluble lignin, stir and mix to dissolve each other, and form an emulsion; 3) Preparation of water-soluble fertilizer: add humic acid and surfactant to the emulsion, continue stirring, and cool down; when the temperature drops below 32°C, add Penicillium microscopy, potassium silicate, and propolis, stir evenly to make a water-soluble fertilizer.

9. The preparation method according to claim 8, characterized in that: Step 1) The method for preparing long-chain fatty acids is as follows: add vegetable oil, and / or animal oil, and / or waste cooking oil, as well as saccharifying enzyme and amylase into a reaction tank, stir and heat to 80°C to 120°C to perform saccharification reaction to generate unsaturated fatty acids; cool to 50°C to 70°C, add hydrogen peroxide coupling agent, continue stirring and heating to generate long-chain fatty acids.

10. The preparation method according to claim 8, characterized in that: In step 3), sodium dodecylbenzene sulfonate, or one or more of urea, dipotassium hydrogen phosphate, calcium magnesium soluble fertilizer, and boron zinc soluble fertilizer are added; or after step 3), one or more of urea, dipotassium hydrogen phosphate, calcium magnesium soluble fertilizer, and boron zinc soluble fertilizer are added, and stirred evenly.

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