Fertilizer special for black land protection

Abstract

The invention relates to the technical field of fertilizers, and particularly discloses a special fertilizer for black land protection. The special fertilizer for black land protection comprises the following components in percentage by weight: 10-12% of a calcium supplement, 15-20% of a silicon-calcium-magnesium fertilizer, 0.5-1.0% of a microbial agent, 25-27% of a biostimulant, 1.5-2.5% of a humic acid-polyacrylic acid cross-linked substance, 3-5% of leaf mold, 3-5% of bentonite, 3.5-4.5% of modified pottery sand and the balance of volcanic soil. According to the special fertilizer for the black land, the degeneration process of the black land can be effectively restrained, moisture and nutrition can be fully kept around roots of crops, an excellent environment is created for growth and development of the crops, the effects in all aspects highly accord with the current situation of the black land, and the special fertilizer has important significance on protection of black land resources.

Description

Technical Field

[0001] This application relates to the field of fertilizer technology, and more specifically, to a special fertilizer for black soil protection. Background Technology

[0002] Currently, the degradation of the black soil in Northeast China is mainly manifested in four aspects: First, long-term cultivation and insufficient return of organic materials to the field have led to the continuous consumption of organic matter, the core material of black soil, resulting in decreased soil fertility and structural deterioration. In some areas, the soil has even shifted from a carbon sink to a carbon source. Second, under the combined effects of wind and water erosion, the black soil layer is thinning year by year, and some areas have already experienced the phenomenon of "broken skin and yellowing," which seriously threatens the stability of the topsoil. Third, repeated compaction by large agricultural machinery and unreasonable cultivation have led to soil compaction, increased bulk density, and reduced porosity, directly affecting soil aeration and water permeability and crop root growth. In addition, the excessive application of chemical fertilizers in pursuit of short-term yields has not only exacerbated soil acidification and compaction but also led to an imbalance of micronutrients and the accumulation of pesticide residues, posing a lasting threat to the soil ecosystem.

[0004] In response to the systemic degradation problem currently facing black soil, the inventors believe that traditional nitrogen, phosphorus, and potassium compound fertilizers are no longer sufficient to meet the urgent needs of black soil protection and restoration. Therefore, there is an urgent need to develop a new type of multifunctional special fertilizer that, when combined with scientific farming methods, can achieve the core goal of "combining land use with land conservation," thereby effectively protecting the precious black soil resources. Summary of the Invention

[0005] In related technologies, traditional nitrogen, phosphorus and potassium compound fertilizers are no longer able to meet the urgent needs of black soil protection and restoration. In order to improve this deficiency, this application provides a special fertilizer for black soil protection.

[0006] This application provides a special fertilizer for black soil protection, employing the following technical solution:

[0007] A special fertilizer for black soil protection comprises the following components by weight percentage: 10-12% calcium supplement, 15-20% silicon-calcium-magnesium fertilizer, 0.5-1.0% microbial agent, 25-27% biostimulant, 1.5-2.5% humic acid-polyacrylic acid crosslinking agent, 3-5% leaf mold, 3-5% bentonite, 3.5-4.5% modified ceramic sand, with the balance made up to 100% from volcanic soil; the modified ceramic sand has polyacrylic acid segments grafted onto its surface, and the biostimulant includes humic acid.

[0008] By adopting the above technical solution, this application, while selecting silicon-calcium-magnesium fertilizer, also adds a calcium supplement as an auxiliary, constructing a micronutrient supplementation system that primarily supplements calcium and secondarily supplements silicon and magnesium. This system can more persistently regulate soil pH, creating more favorable activity conditions for beneficial microorganisms introduced by the inoculant. Simultaneously, the increased calcium content can alleviate the antagonistic effect of ammonium ions left over from nitrogen fertilizer application on the absorption of calcium and magnesium, allowing crops to absorb micronutrients more comprehensively. This application also constructs an ideal three-phase soil structure through the synergistic combination of humic acid-polyacrylic acid crosslinking material, bentonite, volcanic soil, and modified ceramic sand. In this three-phase structure, humic acid-polyacrylic acid crosslinking material and modified ceramic sand bind fine soil particles together through polyacrylic acid segments, enhancing the soil's water and fertilizer retention capacity and mitigating calcium ion loss, thus helping to maintain a high-calcium environment in the soil. Meanwhile, bentonite and volcanic soil particles fill the spaces between soil particles and connect with the pores in the modified ceramic sand, jointly creating an ideal soil environment that is both loose and breathable while retaining water and fertilizer. Based on the aforementioned environment, leaf mold directly replenishes the soil with organic matter and improves soil permeability and water retention, providing food and habitat for microorganisms. Meanwhile, biostimulants, represented by humic acid, significantly enhance soil microbial activity, promote the turnover of elements such as carbon and phosphorus, and improve soil biofertility, enabling degraded black soil to rapidly accumulate organic matter. The black soil-specific fertilizer of this application not only effectively curbs the degradation process of black soil but also effectively retains water and nutrients around crop roots, creating an excellent environment for crop growth and development. Its various effects are highly compatible with the current state of black soil and are of great significance for the protection of black soil resources.

[0009] Preferably, the biostimulant also includes γ-polyglutamic acid.

[0010] By employing the above technical solution, γ-polyglutamic acid, containing a large number of peptide bonds and negatively charged free carboxyl groups, can synergistically interact with humic acid-polyacrylic acid crosslinks and polyacrylic acid segments in modified ceramic sand, improving the binding effect on soil particles, enhancing the soil's water and fertilizer retention capacity, and mitigating calcium ion loss. Simultaneously, γ-polyglutamic acid can also counteract the acidifying effect of humic acid on the soil, retaining the beneficial effects of humic acid while preventing the deepening of soil acidification, making it particularly suitable for use on severely acidified black soils.

[0011] Preferably, the weight ratio of humic acid to γ-polyglutamic acid is (10-12):1.

[0012] By adopting the above technical solution, this application optimizes the ratio of humic acid to γ-polyglutamic acid, which helps to fully exert the beneficial effect of humic acid while maintaining pH stability.

[0013] Preferably, the biostimulant further includes nitrated humic acid, wherein the weight ratio of nitrated humic acid to humic acid is 1:(35-40).

[0014] By adopting the above technical solution, nitrated humic acid, a product obtained from the oxidation and degradation of humic acid by nitric acid, can not only inhibit urease activity and reduce urea loss, but also promote root absorption of phosphorus. Simultaneously, nitrated humic acid can absorb and store potassium ions, enabling the slow release of potassium fertilizer, which helps to fully utilize the natural nitrogen, phosphorus, and potassium elements in the soil. Furthermore, nitrated humic acid can undergo chelation reactions with insoluble trace elements to form chelates that are soluble and easily absorbed by crops, making it particularly suitable for black soils with insufficient soluble trace element content after degradation.

[0015] Preferably, the biostimulant also includes lactopeptide.

[0016] By adopting the above technical solutions, lactose peptides can regulate the secretion of hormones inside crops, which helps to enhance the absorption of nutrients and water by crops. At the same time, it can also make the chelate formed by nitrated humic acid and insoluble trace elements easier to be absorbed by crops, which helps to fully utilize fertilizer fertility.

[0017] Preferably, the humic acid-polyacrylic acid crosslinker is prepared according to the following method:

[0018] (1) Mix weathered lignite, NaOH, Na2S2O3 and deionized water and stir evenly; react at room temperature and then filter; neutralize the filtrate to neutral, let it stand to precipitate and then filter again; dry the filtrate at 70°C to obtain weathered lignite humic acid; mix acrylic acid, NaOH, deionized water, KPS and MBA, stir evenly, heat to react, dry and then crush to obtain polyacrylic acid resin;

[0019] (2) The weathered lignite humic acid, polyacrylic acid resin, APS and MBA solution are mixed and heated in a vacuum drying oven to obtain humic acid-polyacrylic acid crosslinked product.

[0020] By adopting the above technical solution, this application first prepared weathered lignite humic acid and polyacrylic acid resin particles, respectively. Then, using the polyacrylic acid resin particles as a matrix, a cross-linking reaction of weathered lignite humic acid and MBA was initiated on the particle surface, resulting in core-shell particles with a polyacrylic acid resin core and a humic acid cross-linked surface, namely, humic acid-polyacrylic acid cross-linked products. Humic acid-polyacrylic acid cross-linked products can absorb a large amount of water through the internal polyacrylic acid resin, adhere to soil particles through the surface humic acid cross-linked products, and adsorb metal ions, thereby helping to enhance the soil's water and fertilizer retention capacity.

[0021] Preferably, the calcium supplement includes a primary calcium supplement and an auxiliary calcium supplement, wherein the primary calcium supplement includes eggshell powder and the auxiliary calcium supplement includes calcium citrate.

[0022] By adopting the above technical solution, this application prefers eggshell powder and calcium citrate together as calcium supplements. Eggshell powder can react slowly with acidic substances accumulated in the soil to provide calcium that can be released over a long period of time, while calcium citrate is more easily absorbed by plants and can provide sufficient calcium in a short period of time. This helps to ensure the continuous supply and efficient utilization of calcium, and is especially suitable for the restoration and protection of severely acidified black soil.

[0023] Preferably, the calcium-magnesium molar ratio of the silicon-calcium-magnesium fertilizer is (4.0-4.5):1.

[0024] By adopting the above technical solution, this application optimizes the calcium-magnesium ratio, avoids the antagonistic effect between calcium and magnesium, promotes the balanced absorption of both by plants, and helps to increase crop yields on degraded black soil.

[0025] Preferably, the calcium supplement also includes amino acid chelated calcium.

[0026] By adopting the above technical solutions, amino acid chelated calcium is easily absorbed and transported by plants, and can synergistically provide a fast-acting calcium source with calcium citrate, which helps to improve the utilization efficiency of calcium by crops.

[0027] Preferably, the modified ceramic sand is prepared according to the following method:

[0028] (1) Add γ-methacryloxypropyltrimethoxysilane to an aqueous ethanol solution to obtain a silane solution. Add ceramic sand to the silane solution and heat it. After keeping the reaction at the temperature, filter it and dry the ceramic sand to obtain silanized ceramic sand.

[0029] (2) Dissolve carboxymethyl cellulose in water, heat and stir, then cool, add acrylic acid and initiator to the resulting solution, then add silanized ceramic sand, and then heat and react under nitrogen protection. After the reaction is completed, dry and sieve the product to obtain modified ceramic sand.

[0030] By adopting the above technical solution, this application first introduces silane segments with carbon-carbon double bonds onto the surface of ceramic sand, and then initiates a polymerization reaction between the silane segments and acrylic acid to obtain modified ceramic sand with polyacrylic acid segments on the surface. The modified ceramic sand, while possessing a well-developed porous structure internally, can also bond with soil particles through the polyacrylic acid segments on its surface, which helps to significantly improve the soil's water and fertilizer retention capacity, as well as its aeration and permeability, thus helping to alleviate soil compaction.

[0031] In summary, this application has the following beneficial effects:

[0032] 1. The black soil-specific fertilizer of this application can not only effectively curb the degradation process of black soil, but also fully retain water and nutrients around the roots of crops, creating an excellent environment for crop growth and development. Its effects in all aspects are highly consistent with the current situation of black soil and are of great significance for the protection of black soil resources.

[0033] 2. The humic acid-polyacrylic acid crosslinking compound of this application can absorb a large amount of water through the internal polyacrylic acid resin, can adhere to soil particles through the surface humic acid crosslinking compound, and can also adsorb metal ions, thereby helping to enhance the soil's water and fertilizer retention capacity.

[0034] 3. This application preferentially selects eggshell powder, calcium citrate, and amino acid chelated calcium as calcium supplements. Eggshell powder can slowly react with acidic substances accumulated in the soil, providing calcium that can be released over a long period. Calcium citrate is relatively easier for plants to absorb, and through synergistic effects with amino acid chelated calcium, it can provide sufficient calcium in a short time, helping to ensure a continuous supply and efficient utilization of calcium, making it particularly suitable for the restoration and protection of severely acidified black soil. Detailed Implementation

[0035] The present application will be further described in detail below with reference to the embodiments, preparation examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0036] Preparation example of humic acid-polyacrylic acid crosslinking

[0037] The following explanation uses Preparation Example 1 as an example.

[0038] Preparation Example 1

[0039] In this preparation example, the solute of the MBA solution is MBA, the solvent is methanol and water, the volume ratio of methanol to water is 1.8, and the mass fraction of MBA is 10 wt%; MBA is N,N′-methylenebisacrylamide, and KPS is sodium persulfate.

[0040] In this preparation example, the humic acid-polyacrylic acid crosslinker was prepared according to the following method:

[0041] (1) Mix 63.7g of weathered lignite, 3.5g of NaOH, Na2S2O3 and 500g of deionized water, stir evenly, react at 25℃ for 2h and then filter, neutralize the filtrate to neutral, let it stand to precipitate for 9h and then filter again; dry the filtrate at 70℃ to obtain weathered lignite humic acid; mix 30g of acrylic acid, 12g of NaOH, 100g of deionized water, 0.01g of KPS and 0.003g of MBA, stir evenly, heat at 80℃ for 5h and dry at 80℃ for 12h and then crush to obtain polyacrylic acid resin with an average particle size of 200μm;

[0042] (2) The weathered lignite humic acid, polyacrylic acid resin, APS and MBA solution were mixed in a weight ratio of 1:9:0.015:10 and heated in a vacuum drying oven at 80°C for 30 min to obtain humic acid-polyacrylic acid crosslinking.

[0043] Preparation example of modified ceramic sand

[0044] The following explanation uses Preparation Example 2 as an example.

[0045] Preparation Example 2

[0046] In this preparation example, the ceramic sand is a crushed product of clay ceramsite with a bulk density of 700 kg / m³. 3 After soaking in water for 24 hours, the water absorption rate was 6.2 wt%, and the average particle size was 3.75 mm.

[0047] In this preparation example, the modified ceramic sand was prepared according to the following method:

[0048] (1) Add γ-methacryloxypropyltrimethoxysilane to an aqueous ethanol solution (ethanol and water are mixed in advance at a volume ratio of 1:2) to obtain a 1wt% silane solution. Add ceramic sand to the silane solution, heat at 65°C, keep the reaction at 65°C for 2 hours, filter, and dry the ceramic sand at 105°C to constant weight to obtain silanized ceramic sand. In this step, the amount of γ-methacryloxypropyltrimethoxysilane used is 3.5% of the total weight of ceramic sand.

[0049] (2) Dissolve carboxymethyl cellulose in water, heat and stir at 60°C for 1 hour, then cool, add acrylic acid and initiator to the resulting solution, then add silanized ceramic sand, and then heat and react under nitrogen protection. After the reaction is completed, dry and sieve the product to obtain modified ceramic sand. In this step, the weight ratio of carboxymethyl cellulose, water, acrylic acid and initiator is 1:30:5:0.01, and the molar ratio between acrylic acid used in this step and γ-methacryloyloxypropyltrimethoxysilane used in step (1) is 20:1.

[0050] Example

[0051] Examples 1-3

[0052] The following description uses Example 1 as an example.

[0053] Example 1

[0054] In this embodiment, the calcium supplement is eggshell powder with an average particle size of 350 μm, the calcium-magnesium molar ratio of the silicon-calcium-magnesium fertilizer is 5:1, each 5 kg of the bacterial agent contains 80 billion units of compound functional bacteria (Bacillus subtilis, Bacillus licheniformis, Bacillus mucilaginosus, and Trichoderma harzianum in a ratio of 40:40:15:5), the biostimulant is humic acid, and the method of obtaining it is the same as that of the weathered lignite humic acid in Preparation Example 1. The humic acid-polyacrylic acid crosslinking compound is prepared according to the method of Preparation Example 1, the modified ceramic sand is prepared according to the method of Preparation Example 2, the leaf mold is the topsoil 3 cm thick under pine and cypress trees, the bentonite is calcium-based bentonite, and the volcanic soil is taken from Changle, Shandong.

[0055] This embodiment provides a special fertilizer for black soil protection, comprising the following components by weight percentage: 10% calcium supplement, 20% silicon-calcium-magnesium fertilizer, 0.5% microbial agent, 27% biostimulant, 2.5% humic acid-polyacrylic acid crosslinker, 3% leaf mold, 5% bentonite, 3.5% modified ceramic sand, with the remainder made up to 100% from volcanic soil.

[0056] As shown in Table 1, the main difference between Examples 1-3 lies in the different raw material ratios of the special fertilizer for black soil protection.

[0057] Table 1 Raw material ratio of special fertilizer for black soil protection

[0058]

[0059] Example 4

[0060] The difference between this embodiment and Embodiment 3 is that the biostimulant also includes γ-polyglutamic acid, with an average of 200,000 γ-polyglutamic acid, and the weight ratio of humic acid to γ-polyglutamic acid is 15:1.

[0061] Examples 4-7

[0062] As shown in Table 2, the difference between Examples 4-7 is that the weight ratio of humic acid to γ-polyglutamic acid is different.

[0063] Table 2 Weight ratio of humic acid to γ-polyglutamic acid

[0064]

[0065] Example 8

[0066] The difference between this embodiment and embodiment 7 is that the biostimulant also includes nitrated humic acid, and the weight ratio of nitrated humic acid to humic acid is 1:40.

[0067] As shown in Table 3, the difference between Examples 8-10 is that the weight ratio of nitrated humic acid to humic acid is different.

[0068] Table 3 Weight ratio of nitrated humic acid to humic acid

[0069]

[0070] Example 11

[0071] The difference between this embodiment and Embodiment 10 is that the biostimulant also includes lactose peptides, and the amount of lactose peptides is 10% of the weight of humic acid.

[0072] Example 12

[0073] The difference between this embodiment and Embodiment 11 is that the calcium supplement also includes calcium citrate, and the weight ratio of calcium citrate to eggshell powder is 1:7.

[0074] Example 13

[0075] The difference between this embodiment and Embodiment 12 is that the calcium-magnesium molar ratio of the silicon-calcium-magnesium fertilizer is 4.5:1.

[0076] As shown in Table 4, the difference between Examples 13-15 is that the calcium-magnesium molar ratio of the silicon-calcium-magnesium fertilizer is different.

[0077] Table 4. Calcium-magnesium molar ratio of silicon-calcium-magnesium fertilizer

[0078]

[0079] Example 16

[0080] The difference between this embodiment and Embodiment 15 is that the calcium supplement also includes amino acid chelated calcium, and the weight ratio of amino acid chelated calcium to eggshell powder is 1:10.

[0081] Comparative Example

[0082] Comparative Example 1

[0083] The difference between this comparative example and Example 1 is that the components of the special fertilizer for black soil protection do not include calcium supplements.

[0084] Comparative Example 2

[0085] The difference between this comparative example and Example 1 is that the components of the special fertilizer for black soil protection do not include biostimulants.

[0086] Comparative Example 3

[0087] The difference between this comparative example and Example 1 is that the components of the special fertilizer for black soil protection do not include humic acid-polyacrylic acid crosslinking.

[0088] Comparative Example 4

[0089] The difference between this comparative example and Example 1 is that the components of the special fertilizer for black soil protection do not include leaf mold.

[0090] Comparative Example 5

[0091] The difference between this comparative example and Example 1 is that the components of the special fertilizer for black soil protection do not include bentonite.

[0092] Comparative Example 6

[0093] The difference between this comparative example and Example 1 is that the components of the special fertilizer for black soil protection do not include modified ceramic sand.

[0094] Comparative Example 7

[0095] The difference between this comparative example and Example 1 is that the components of the special fertilizer for black soil protection do not include humic acid-polyacrylic acid crosslinking agent and modified ceramic sand.

[0096] Performance testing methods

[0097] The test was conducted on degraded black soil in Northeast China due to long-term cultivation. The soil pH was 6.38, and the soil organic matter content was 24.45 g / kg. The test crop was soybean, variety Heinong 48, and the commercially available nitrogen-phosphorus-potassium fertilizer had a nitrogen-phosphorus-potassium ratio (molar ratio) of 1:1:3.

[0098] Test method:

[0099] The study divided soybeans into a control group and an experimental group. The control group received only 2 kg of commercially available nitrogen, phosphorus, and potassium fertilizer per mu (approximately 0.067 hectares), while the experimental group received both 2 kg of commercially available nitrogen, phosphorus, and potassium fertilizer and 2 kg of special fertilizer for black soil conservation per mu. Soybean seeds were first mixed with the fertilizer, and then sown at a density of 15,000 plants per mu. Each group's test area was 10 mu (approximately 0.67 hectares). Soybeans were harvested when they reached yellow maturity, and the yield per mu was calculated. The yield per mu of the experimental group was then divided by the yield per mu of the control group, and the ratio was subtracted by 100% to obtain the yield increase rate. The results are shown in Table 5.

[0100] Table 5 Production Increase Rate

[0101]

[0102] As can be seen from Examples 1-3 and Table 5, the yield increase rate measured in Examples 1-3 was significantly higher than that of the control group. This is because this application introduced more calcium to address the low pH characteristics of degraded black soil, and enhanced the soil's water and fertilizer retention capacity through the synergistic combination of humic acid-polyacrylic acid crosslinking agent, bentonite, volcanic soil, and modified ceramic sand, while mitigating calcium ion loss. This allowed the black soil to maintain a pH range suitable for crop growth for a longer period. Furthermore, the humic acid, microbial agents, and leaf mold added in this application altered the organic matter-poor state of degraded black soil, not only replenishing organic matter but also accelerating its accumulation. With the synergistic effect of various components, the soil physical structure, pH, and organic matter content of degraded black soil were significantly improved, creating an excellent environment for crop growth and development. Consequently, the yield per acre was much higher than that of the control group treated with conventional nitrogen, phosphorus, and potassium fertilizers alone.

[0103] Combining Example 1 and Comparative Example 1 with Table 5, it can be seen that the yield increase rate measured in Example 1 is significantly higher than that in Comparative Example 1. This is because Comparative Example 1 lacks calcium supplements, making it difficult to completely neutralize the acidic substances in the degraded black soil and create the most suitable growth environment for crops. As a result, the yield per acre has declined compared to Example 1.

[0104] Combining Example 1 and Comparative Example 2 with Table 5, it can be seen that the yield increase rate measured in Example 1 is significantly higher than that in Comparative Example 2. This is because Comparative Example 2 lacks biostimulants, so the microorganisms introduced by the inoculant did not fully modify the soil environment, thus affecting the yield per acre.

[0105] Combining Example 1 and Comparative Example 3 with Table 5, it can be seen that the yield increase rate measured in Example 1 is significantly higher than that in Comparative Example 3. This is because Comparative Example 3 lacks humic acid-polyacrylic acid crosslinking, resulting in limited improvement effect of fertilizer on soil physical structure and insufficient restoration of soil water and fertilizer retention capacity. Therefore, the yield per acre has declined compared with Example 1.

[0106] Combining Example 1 and Comparative Example 4 with Table 5, it can be seen that the yield increase rate measured in Example 1 is slightly higher than that in Comparative Example 4. This is because Comparative Example 4 lacks leaf mold, thus providing a limited initial total amount of organic matter. In this case, the microorganisms introduced by the inoculant did not fully modify the soil environment, thereby affecting the yield per acre.

[0107] Combining Example 1 and Comparative Example 5 with Table 5, it can be seen that the yield increase rate measured in Example 1 is significantly higher than that in Comparative Example 5. This is because Comparative Example 5 lacks bentonite, which results in limited improvement of soil physical structure by fertilizer and insufficient restoration of soil water and fertilizer retention capacity. Therefore, the yield per mu has declined compared with Example 1.

[0108] Combining Example 1 and Comparative Example 6 with Table 5, it can be seen that the yield increase rate measured in Example 1 is significantly higher than that in Comparative Example 6. This is because Comparative Example 6 lacks modified ceramic sand, so air and moisture cannot diffuse through the porous structure of the ceramic sand, nor can they be stored in the porous structure of the ceramic sand. Humic acid-polyacrylic acid crosslinking alone cannot fully bind soil particles, so the soil's water and fertilizer retention capacity is not fully restored, and therefore the yield per acre is lower than that in Example 1.

[0109] Combining Example 1 and Comparative Example 7 with Table 5, it can be seen that the yield increase rate measured in Example 1 is significantly higher than that in Comparative Example 7. This is because the fertilizer in Comparative Example 7 lacks humic acid-polyacrylic acid crosslinking agent and modified ceramic sand, which affects the absorption efficiency of water and nutrients by crop roots, resulting in a lower final yield increase rate.

[0110] Combining Examples 3 and 4-7 with Table 5, it can be seen that the yield increase rate of Examples 4-7 gradually increases. This is because γ-polyglutamic acid contains a large number of peptide bonds and negatively charged free carboxyl groups, which can synergistically interact with the humic acid-polyacrylic acid crosslinker and the polyacrylic acid segments in the modified ceramic sand, improving the binding effect on soil particles, enhancing the soil's water and fertilizer retention capacity, and mitigating calcium ion loss. Simultaneously, γ-polyglutamic acid can also counteract the acidifying effect of humic acid on the soil, retaining the beneficial effects of humic acid while preventing the deepening of soil acidification, making it particularly suitable for use on severely acidified black soil. Especially when the weight ratio of humic acid to γ-polyglutamic acid is (10-12):1, it can maintain pH stability while fully utilizing the beneficial effects of humic acid.

[0111] Combining Examples 7 and 8-10 with Table 5, it can be seen that the yield increase rates measured in Examples 8-10 are all higher than those in Example 7, and increase sequentially. This is because nitrated humic acid can inhibit urease activity, reduce urea loss, and promote root absorption of phosphorus. Simultaneously, nitrated humic acid can absorb and store potassium ions, enabling the slow release of potassium fertilizer, which helps to fully utilize the natural nitrogen, phosphorus, and potassium elements in the soil. Furthermore, nitrated humic acid can chelate with insoluble trace elements to form chelates that are soluble and easily absorbed by crops, making it particularly suitable for black soils with insufficient soluble trace element content after degradation. When the weight ratio of nitrated humic acid to humic acid is 1:(35-40), the yield increase effect on crops is relatively good.

[0112] As can be seen from Examples 10 and 11 and Table 5, the yield increase rate measured in Example 11 is higher than that in Example 10. This is because lactose peptides can regulate the secretion of hormones inside crops, which helps to enhance the absorption of nutrients and water by crops. At the same time, it can also make the chelate formed by nitrated humic acid and insoluble trace elements easier to be absorbed by crops, which helps to fully utilize fertilizer fertility.

[0113] As can be seen from Examples 11 and 12 and Table 5, the yield increase rate measured in Example 12 is higher than that in Example 11. This is because the newly added calcium supplement calcium citrate is more easily absorbed by plants and can provide sufficient calcium in a short time, which helps to ensure the continuous supply and efficient utilization of calcium, and is especially suitable for the restoration and protection of severely acidified black soil.

[0114] As can be seen from Examples 12, 13-15 and Table 5, the yield increase rate measured in Examples 13-15 is higher than that in Example 12. This is because, based on the aforementioned examples, further adjusting the calcium-magnesium molar ratio of the silicon-calcium-magnesium fertilizer to (4.0-4.5):1 can avoid the antagonistic effect between calcium and magnesium, promote the balanced absorption of calcium and magnesium by plants, and help increase the yield of crops on degraded black soil.

[0115] As can be seen from Examples 15 and 16 and Table 5, the yield increase rate measured in Example 16 is higher than that in Example 15. This is because amino acid chelated calcium is easily absorbed and transported by plants and can synergistically provide a fast-acting calcium source with calcium citrate, which helps to improve the utilization efficiency of calcium by crops.

[0116] The above embodiments are merely explanations of this application and are not intended to limit it. After reading this specification, those skilled in the art can make modifications to the embodiments of this application without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of this application.

Claims

1. A special fertilizer for black soil protection, characterized in that, The product comprises the following components by weight percentage: 10-12% calcium supplement, 15-20% silicon-calcium-magnesium fertilizer, 0.5-1.0% microbial agent, 25-27% biostimulant, 1.5-2.5% humic acid-polyacrylic acid crosslinker, 3-5% leaf mold, 3-5% bentonite, 3.5-4.5% modified ceramic sand, with the balance made up to 100% from volcanic soil; the modified ceramic sand has polyacrylic acid segments grafted onto its surface, and the biostimulant includes humic acid.

2. The special fertilizer for black soil protection according to claim 1, characterized in that, The biostimulant also includes γ-polyglutamic acid.

3. The special fertilizer for black soil protection according to claim 2, characterized in that, The weight ratio of humic acid to γ-polyglutamic acid is (10-12):

1.

4. The special fertilizer for black soil protection according to claim 2, characterized in that, The biostimulant also includes nitrated humic acid, wherein the weight ratio of nitrated humic acid to humic acid is 1:(35-40).

5. The special fertilizer for black soil protection according to claim 4, characterized in that, The biostimulants also include lactopeptides.

6. The special fertilizer for black soil protection according to claim 1, characterized in that, The humic acid-polyacrylic acid crosslinker was prepared according to the following method: (1) Mix weathered lignite, NaOH, Na2S2O3 and deionized water and stir evenly; react at room temperature and then filter; neutralize the filtrate to neutral, let it stand to precipitate and then filter again; dry the filtrate at 70°C to obtain weathered lignite humic acid; mix acrylic acid, NaOH, deionized water, KPS and MBA, stir evenly, heat to react, dry and then crush to obtain polyacrylic acid resin; (2) The weathered lignite humic acid, polyacrylic acid resin, APS and MBA solution are mixed and heated in a vacuum drying oven to obtain humic acid-polyacrylic acid crosslinked product.

7. The special fertilizer for black soil protection according to claim 1, characterized in that, The calcium supplement includes a primary calcium supplement and an auxiliary calcium supplement. The primary calcium supplement includes eggshell powder, and the auxiliary calcium supplement includes calcium citrate.

8. The special fertilizer for black soil protection according to claim 7, characterized in that, The calcium-magnesium molar ratio of the silicon-calcium-magnesium fertilizer is (4.0-4.5):

1.

9. The special fertilizer for black soil protection according to claim 7, characterized in that, The calcium supplement also includes amino acid chelated calcium.

10. The special fertilizer for black soil protection according to claim 1, characterized in that, The modified ceramic sand is prepared according to the following method: (1) Add γ-methacryloxypropyltrimethoxysilane to an aqueous ethanol solution to obtain a silane solution. Add ceramic sand to the silane solution and heat it. After keeping the reaction at the temperature, filter it and dry the ceramic sand to obtain silanized ceramic sand. (2) Dissolve carboxymethyl cellulose in water, heat and stir, then cool, add acrylic acid and initiator to the resulting solution, then add silanized ceramic sand, and then heat and react under nitrogen protection. After the reaction is completed, dry and sieve the product to obtain modified ceramic sand.

Images