Preparation method of liquid fertilizer containing polyphosphate and synergistic stability and fertilizer

Abstract

The invention discloses a preparation method and fertilizer of a liquid fertilizer containing polyphosphate stability and synergistic effect, wherein liquid phosphoric acid and urea are subjected to polymerization reaction to generate polyphosphate urea liquid, the polyphosphate urea liquid is then subjected to secondary polymerization with ammonia water to prepare a first mixed solution of ammonium polyphosphate, ammonium phosphate and polyphosphate urea, the pH value is adjusted to 6.5-7.5, and the mixture is fully stirred, mixed and packaged to obtain a finished product. After the first mixed solution is generated and before the pH value is adjusted, sulfonated straw powder after fermentation is added to the first mixed solution, SO3 is introduced and formaldehyde solution is added dropwise to generate phosphorylated lignin, a chelate reaction is carried out at room temperature to form a second mixed solution containing chelated lignin and amino acids, and a suspending agent is added. The purpose of the invention is to reduce production costs, improve the water solubility of phosphorus, enrich the nutrient content of liquid fertilizer, make it unnecessary to add other fertilizers during the application process of liquid fertilizer, and further achieve weight loss and synergistic effect.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural fertilizer preparation, and relates to a preparation method of liquid fertilizer and fertilizer, and in particular to a preparation method of liquid fertilizer containing polyphosphate stability and synergistic fertilizer and fertilizer. Background Art

[0002] my country is a major agricultural country. Traditional granular fertilizers require large amounts of fertilizer, and long-term use will reduce the soil's carrying capacity. Traditional granular fertilizers can no longer meet the needs of modern agricultural science and technology. People urgently need a new type of fertilizer that is stable in quality, low in price, and has the ability to reduce weight and increase efficiency.

[0003] Liquid fertilizers are more conducive to crop absorption and utilization because their main active ingredients are in a dissolved state. Facts have proved that the use of liquid fertilizers can reduce the amount of fertilizer applied and increase agricultural product yields.

[0004] It can be seen that liquid fertilizer is still in its infancy in my country's agriculture and there is still a lot of room for development. Therefore, people are constantly studying the components and processes of liquid fertilizers. For example, the literature number is CN

[0005] Chinese patent application 112592242A, "A Polymeric Oligophosphate Long-Release Fertilizer and Production Process," discloses a liquid fertilizer that replaces ammonium phosphate with a low-polymerization urea phosphate or ammonium polyphosphate. This delays the phosphorus fixation time in the soil, improves phosphorus utilization, and improves soil pH, thereby reducing fertilizer application and achieving the goal of reducing fertilizer consumption and increasing efficiency. The technology uses pure phosphoric acid as the raw material, with the addition of ammonium bicarbonate as a catalyst. The degree of polymerization is controlled between 3.5 and 4.5, and the pH is controlled between 1.9 and 2.4. Although the water solubility of phosphorus in this technology reaches 90%, it is not fully water-soluble. The resulting liquid fertilizer has a single component and is incomplete in function, requiring the addition of other fertilizers to meet crop growth needs. Summary of the Invention

[0006] The purpose of the present invention is to further improve the water solubility of phosphorus, enrich the nutritional components of liquid fertilizer, and make it unnecessary to add other fertilizers during the application process of liquid fertilizer, thereby further achieving weight loss and efficiency improvement. The present invention provides a preparation method and fertilizer of a stable and synergistic liquid fertilizer containing polymerized phosphorus with more comprehensive nutritional components and richer components.

[0007] The technical solution adopted by the present invention is a preparation method of a liquid fertilizer containing polyphosphate-containing stable synergistic fertilizer, wherein liquid phosphoric acid and urea are subjected to a polymerization reaction to generate a polyurea phosphate liquid, the polyurea phosphate liquid is then subjected to a secondary polymerization with ammonia water to obtain a first mixed solution of ammonium polyphosphate, ammonium phosphate and polyurea phosphate, the pH value is adjusted to 6.5-7.5, and the finished product is packaged. The key to the above process is that after the first mixed solution is generated and before the pH value is adjusted, fermented and sulfonated straw powder is added to the first mixed solution, SO3 is introduced and formaldehyde solution is added dropwise to generate phosphorylated lignin, a chelating reaction is carried out at room temperature to form a second mixed solution containing chelated lignin and amino acids, a suspending agent is added, and the mixture is fully stirred and mixed.

[0008] Furthermore, after the second mixed solution is generated and before the suspending agent is added, biochemical potassium fulvic acid is added to the second mixed solution to carry out a complex reaction to form a third mixed solution containing polymerized amino acids, potassium phosphate, and small molecular compounds of fulvic acid.

[0009] Furthermore, the particle size of the straw powder is 200 mesh.

[0010] Furthermore, the above polymerization reaction and secondary polymerization reaction are both carried out under the action of a catalyst, and the catalyst used is one or a combination of sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and sodium carbonate, and the catalyst dosage is 0.8‰ to 1.2‰.

[0011] Furthermore, in the above polymerization reaction and secondary polymerization reaction, a chemical reaction controller is used to control the reaction progress, the polymerization degree of ammonium polyphosphate is 9% to 15%, and the amount of the chemical reaction controller is 0.4‰ to 1.0‰.

[0012] Furthermore, the concentration of the ammonia water is 30% to 40%, and the liquid phosphoric acid is concentrated liquid phosphoric acid containing 45% to 60% phosphorus pentoxide. During the preparation process, brown algal oligosaccharides, urease inhibitors, nitrification inhibitors, potassium chloride or potassium sulfate are added. The urease inhibitor is one or a combination of thiourea and methylphosphoric triamide, and the nitrification inhibitor is one or a combination of dicyandiamide, 2-chloro-methylpyridine and hydroquinone.

[0013] The stable and synergistic liquid fertilizer containing polymeric phosphorus is prepared by the above-mentioned preparation method. The key lies in that its components include 20-35 parts of polyurea phosphate, 35-55 parts of ammonium polyphosphate, 5-10 parts of ammonium phosphate, 0.1-30 parts of potassium chloride or potassium sulfate, 1-2 parts of ammonium sulfate, 0.1-0.2 parts of fulvic acid, 0.1-0.2 parts of chelated lignin, 0.02-0.1 parts of complexed polymeric amino acid small molecule compounds, 0.01-0.02 parts of small molecule functional group compounds formed by phosphoric acid, ammonia and lignin, brown algae oligosaccharide and biochemical fulvic acid, 0.05-0.15 parts of urease inhibitor, 0.05-0.15 parts of nitrification inhibitor and 0.01-0.05 parts of brown algae oligosaccharide.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The polymerized phosphorus-containing stable synergistic liquid fertilizer prepared by the present invention has complete functions, good effects, and rich nutritional ingredients. The components are rich in various amino acids, intermediate elements such as sulfur and various trace elements that are essential for crops, among which the nitrogen and phosphorus content is sufficient, and the release cycle matches the crop growth cycle. At the same time, the components do not produce effects independently, but also have synergistic effects, further improving the absorption and utilization efficiency of various effective ingredients by crops, and can achieve the beneficial effect of producing multiple effects and sufficient duration with one fertilization.

[0016] First, the product has better water solubility, lower production costs and higher production efficiency:

[0017] This invention increases the water solubility of phosphorus from 90% in the prior art to 100% water solubility, thereby improving phosphorus utilization. Using inexpensive, basic raw materials, the reaction can be completed without high temperatures under the action of a catalyst. Fuel and steam heating are not required during the production process, reducing carbon emissions by approximately 30%. While the purity of the pure phosphoric acid used in the prior art is reduced, this method not only avoids the introduction of unnecessary impurities but also ensures reaction progress and product quality. Furthermore, it avoids pipeline blockage and equipment scaling caused by the use of highly viscous pure phosphoric acid, further improving production efficiency.

[0018] The catalyst used in the present invention is more efficient, requires less usage, and reduces ammonia production during use. This reduces air pollution while also reducing foaming in the reactor, increasing the reactor filling rate, improving production efficiency, and further reducing energy consumption. The catalyst containing calcium and magnesium can also supplement the corresponding trace elements required by crops, enriching the variety of nutrients in the present invention.

[0019] Second, phosphorus and nitrogen have high utilization rates and long release periods, which help improve crop quality and yield:

[0020] The effective release period of phosphorus in the polyurea phosphate of the present invention is as long as about 100 days, which is 1.6 to 1.9 times that of the phosphorus in ordinary ammonium phosphate; the effective release period of phosphorus in ammonium polyphosphate is as long as 140 to 150 days, which is 2.3 to 2.7 times that of ordinary ammonium phosphate. In addition, urea phosphate is also a condensate of urea and is a long-acting nitrogen fertilizer, which delays the decomposition time by about 30 to 40 days compared with ordinary urea. The present invention controls the degree of polymerization and adds urease inhibitors and nitrification inhibitors so that the release period of phosphorus and nitrogen can cover the entire growth period of the crop, avoiding the inability of fertilizer to be effectively absorbed due to an excessively long release period and the deposition of fertilizer in the soil due to an excessively short release period, thereby fully improving the utilization rate of phosphorus and nitrogen.

[0021] In addition, the ratio of ammonium polyphosphate, urea polyphosphate and ammonium phosphate in the present invention is appropriate, and the amount released in the initial stage of fertilization is sufficient to meet the needs of rapid growth of crops. The subsequent release rate is almost balanced, which is conducive to the formation of crop dry matter, meets the needs of different growth stages of crops, and improves crop quality and yield.

[0022] Third, the present invention is not easy to precipitate, can improve soil properties, and is more conducive to environmental protection and sustainable agricultural production:

[0023] The small molecular groups in the fully water-soluble chelated lignin of the present invention have long hydroxyl and amino chains and contain multiple functional groups. The hydroxyl chains are negatively charged and can adsorb positively charged ions such as ammonium, potassium, magnesium, calcium, iron, and zinc. The amino chains are positively charged and can adsorb negatively charged nutrient ions such as nitrate nitrogen fertilizer, phosphate, sulfur, and boron. This improves the crop's ability to absorb and utilize nutrient ions while reducing antagonism between nutrient ions, making the liquid fertilizer less likely to precipitate.

[0024] In the present invention, the complexed small molecule amino acids can also promote the exchangeability of various nutrient ions in the soil, promote the activity of various enzymes in the soil, benefit the reproduction of beneficial soil bacteria, improve soil fertility, balance the microbial agents in the soil, improve soil permeability, and increase soil organic matter.

[0025] The fermented sulfonated straw used in the present invention contains lignin with a three-dimensional network structure. Multiple functional groups such as sulfonic acid groups, carboxyl groups, alcoholic hydroxyl groups, and phenolic hydroxyl groups have strong chelating ability. The phosphorylated lignin generated by further reaction further expands the chelating sites. Potassium fulvate also contains multiple active groups such as carboxyl groups and hydroxyl groups, and has oxygen-containing functional groups, resulting in numerous organic chelating sites in the structure. These coordination groups can undergo chelation reactions with various essential trace elements for crops, such as insoluble calcium, magnesium, sulfur, iron, manganese, molybdenum, copper, zinc, and boron. They can also undergo chelation reactions with phosphorus at other sites, thus avoiding direct contact between the trace elements and phosphorus, which would otherwise lead to mutual passivation and inactivation. This plays a positive balancing role, thereby improving the utilization rate of the trace elements and phosphorus by crops.

[0026] In addition, the fermented straw itself also produces a variety of amino acids. Among them, amino acids such as glutamic acid help improve crop root development and promote crop protein formation. Amino acids with hydroxyl groups, such as threonine, serine, and tyrosine, can be further modified with phosphate to form phosphate esters, ultimately forming potassium phosphate esters. Potassium phosphate esters are crop growth regulators that can improve crop survival rates. After absorption by crops, they slowly release the active ingredients nitrophenol, 4-hydroxycoumarin, and triacontanol in the body. This slow-release effect improves the safety of the active ingredients for crops and avoids crop damage, especially in sensitive crops, such as abnormal growth or physiological disorders when using growth regulators such as sodium nitrophenolate or sodium polynitrophenolate.

[0027] In addition, the brown algae oligosaccharides in the components not only directly participate in the synthesis of proteins in crops, but can also form small molecular functional group compounds with phosphoric acid, ammonia, lignin, and biochemical fulvic acid, which are more conducive to promoting crop root growth, activating crop self-defense systems, and regulating crop growth. This makes the absorption and utilization rate of brown algae oligosaccharides by crops in the present invention higher, and reduces the usage of brown algae oligosaccharides by a hundred times, from 2% to 4% of the general usage to about 0.3‰.

[0028] In summary, the polymerized phosphorus-containing stable synergistic liquid fertilizer prepared by the present invention has comprehensive nutritional components and synergistic effects between the components. It not only prolongs the effective release period of nitrogen and phosphorus elements, but also improves the absorption and utilization efficiency of crops for various effective ingredients in the fertilizer, improves crop quality, and meets the nutritional needs of crops throughout the entire growth cycle. One-time fertilization produces multiple effects and the duration is sufficient. At the same time, the raw materials used in the present invention are low in price, the process does not use steam and fuel, the equipment utilization rate is high, the amount of waste gas generated is small, and the production capacity is minimized to achieve the purpose of energy conservation and emission reduction. When the present invention is applied, soil properties can also be improved, soil fertility can be improved, and the needs of environmental protection and sustainable agricultural development can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a reaction process flow chart of the present invention. DETAILED DESCRIPTION

[0030] The present invention provides a method for preparing a stabilized, synergistic liquid fertilizer containing polyphosphate and the fertilizer. The technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0031] The reaction process can be found in the attached Figure 1 , the specific steps are as follows:

[0032] A) Liquid phosphoric acid is quantitatively delivered to the primary reactor. Liquid algal oligosaccharide can be added according to the formulation requirements.

[0033] Compared with pure phosphoric acid, the liquid phosphoric acid used in this embodiment has better fluidity, is less likely to cause pipe blockage and equipment scaling, and can improve production efficiency. The brown algae oligosaccharides in this embodiment can directly participate in the synthesis of proteins in crops, increase the disease resistance, drought resistance, and cold resistance of crops, facilitate the formation of crop dry matter, and further improve crop quality.

[0034] B) adding 30% to 60% of the total catalyst amount and urea to the primary reactor, where the materials in the primary reactor generate polymerized urea phosphate liquid under the action of the catalyst, and adding a chemical reaction control agent to terminate the reaction.

[0035] The catalysts and chemical reaction controllers used in this preparation method are mostly strong bases, which not only have higher catalytic efficiency and reduce the use of catalysts and reaction controllers, but also can reduce ammonia emission during the reaction process, reduce air pollution, and achieve the effect of energy conservation and emission reduction.

[0036] C) Ammonia water is fed into the primary reactor, and brown algal oligosaccharides, a urease inhibitor for nitrogen fertilizer, and a nitrification inhibitor for nitrogen fertilizer are added according to the formulation requirements to prepare a liquid with a nitrogen content of 30% to 50%.

[0037] The added nitrogen fertilizer urease inhibitor can extend the urea decomposition time by 15 to 25 days and reduce the volatilization of ammonia by about 30% or more. The added nitrogen fertilizer nitrification inhibitor can extend the time for ammonium nitrogen fertilizer to be converted into nitrate nitrogen fertilizer, extending the conversion time by 30 to 45 days. When the two are used simultaneously, the release time of nitrogen fertilizer can be extended to more than 100 days, which is more than 1.6 times the release period of ordinary urea in the soil.

[0038] D) adding the remaining catalyst to the liquid to cause a secondary polymerization reaction between the polyurea phosphate liquid and the ammonia water in the primary reactor to produce a mixed solution of ammonium polyphosphate, ammonium phosphate, and polyurea phosphate. A chemical reaction control agent is added to terminate the reaction. The nitrogen fertilizer in the ammonium phosphate in the mixed solution enters the soil mainly in the form of ammonium ions and can be directly absorbed by crops. Polyurea phosphate is a condensate of urea and is a long-acting nitrogen fertilizer. Compared with ordinary urea, the decomposition time of nitrogen fertilizer is extended by 30 to 40 days. In this embodiment, the ratio of the various types of nitrogen fertilizers is appropriate, and the nitrogen requirements of crops at different growth stages are also met.

[0039] E) The mixed solution is transferred to a secondary reactor, and fermented and sulfonated straw powder with a particle size of 200 mesh is added. 10 to 20 L of SO3 is introduced, and 5 to 10 L of a 35 to 40% formaldehyde solution is slowly added dropwise. After the addition is complete, the mixture is stirred for 2 to 4 hours to generate phosphorylated lignin, and a chelation reaction is carried out at room temperature to form a second mixed solution containing chelated lignin and multiple amino acids.

[0040] Straw fertilizer is rich in organic matter, has a balanced nitrogen, phosphorus and potassium nutrient content, and is also rich in trace elements and various amino acids. It has irreplaceable advantages in agricultural production. However, straw fertilizer is in a solid state, easily broken, and has an ammonia smell, which is very inconvenient when stored and used. Moreover, nitrogen, phosphorus and potassium nutrients are still insufficient for the entire growth cycle of crops. This embodiment fully utilizes the rich nutrients in the sulfonated straw powder after fermentation. When SO3 is introduced, rapid heat release occurs locally. The lignin in the straw powder reacts with the ammonium phosphate and urea phosphate in the first mixed solution under the action of formaldehyde to generate lignin sulfonate, which further generates phosphorylated lignin. The phosphorylated lignin not only prevents phosphoric acid from depositing in the soil, but also further expands the chelating sites of the lignin. In the above-mentioned reaction process, no overall heating is required, which not only saves energy but also effectively prevents the decomposition of polyurea phosphate. The above process does not require the addition of additional raw materials required for preparing phosphorylated lignin. The ammonium phosphate and urea phosphate in the first mixed liquid can react with the sulfonated lignin to produce phosphorylated lignin. At the same time, the added SO3 also supplements the sulfur element required for crop growth, further enriching the nutritional content of the liquid fertilizer.

[0041] F) adding biochemical potassium fulvic acid to the mixed solution to carry out a complex reaction to form a mixed solution containing a plurality of polymeric amino acids, potassium phosphate, and small molecular compounds of fulvic acid, thereby further enriching the components of the liquid fertilizer and increasing the content of growth regulators.

[0042] Biochemical potassium fulvate contains high levels of total amino acids and active groups such as carboxyl and hydroxyl groups. It also possesses oxygen-containing functional groups and numerous organic chelating and complexing sites. These ligands not only react with various trace elements essential for crop growth, such as calcium, magnesium, sulfur, iron, zinc, and boron, but also with phosphorus at other sites. This creates a complex with the biochemical fulvate molecule as the intermediary carrier, preventing direct contact between trace elements and phosphorus, which could lead to their mutual deactivation.

[0043] Not only that, the amino acids containing hydroxyl groups produced by straw fermentation, such as threonine, serine, tyrosine, etc., can be further modified by phosphate to generate phosphate esters and finally form potassium phosphate esters. Potassium phosphate esters are crop growth regulators that can improve the survival rate of crops.

[0044] G) Add potassium chloride or potassium sulfate to the above mixture according to the requirements of the fertilization area and crop type.

[0045] H) The mixed solution is transferred to a buffer tank, a suspending agent is added, and the mixture is stirred to obtain a suspended liquid fertilizer. A pH regulator is added to adjust the pH value according to the soil properties of the fertilization area and the needs of the crops.

[0046] J) The liquid fertilizer is fully stirred and mixed, then transported to an automated liquid packaging machine for packaging, and the finished product is obtained after passing the inspection.

[0047] The above description is a detailed description of the preferred embodiment of the present invention, but the embodiment is not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

[0048] The experimental locations and experimental dates of the following specific examples are shown in Table 1.

[0049] Table 1: Experimental field locations and experimental dates

[0050]

[0051] Examples 1 to 3 provide three groups of liquid fertilizers of the present invention with different raw material and auxiliary material ratios, and experiments were carried out on different crops, soils of different properties, and different growing seasons to verify the universal adaptability of the present invention.

[0052] Example 1

[0053] The preparation formula is a polymeric liquid fertilizer with a nitrogen content of 160 g / L and a phosphorus content of 420 g / L, without the addition of potassium sulfate or potassium chloride powder.

[0054] The raw and auxiliary materials used are: 80 kg of granular urea, 500 kg of concentrated liquid phosphoric acid containing 60% phosphorus pentoxide, 420 kg of ammonia water containing 30% nitrogen, 20 kg of fine sulfonated straw powder after fermentation, 10 L of SO3 gas, 5 L of formaldehyde solution, 0.8 kg of catalyst, 0.3 kg of brown algae oligosaccharide; 3 kg of biochemical potassium fulvic acid, 1 kg of urease inhibitor, 1 kg of nitrification inhibitor, 0.5 kg of chemical reaction controller, and 3 kg of pH regulator.

[0055] In the above preparation process, the first catalyst added to the polymerization reaction was 30% of the total catalyst amount, and the remaining catalyst was added in the second time to obtain liquid fertilizer. Compared with ordinary granular fertilizer, it was compared and applied to corn, soybeans in Northeast China, rice in South China, and summer corn in Central China. The specific experimental results are shown in Table 2.

[0056] Example 2

[0057] The preparation formula is a polymeric liquid fertilizer with a nitrogen content of 168g / L, a phosphorus content of 168g / L, and a potassium content of 168g / L.

[0058] The raw and auxiliary materials used are: 140 kg of granular urea, 240 kg of concentrated liquid phosphoric acid containing 60% phosphorus pentoxide, 280 kg of ammonia water containing 30% nitrogen, 270 kg of potassium chloride powder, 70 kg of water, 20 kg of fine sulfonated straw powder after fermentation, 15 L of SO3 gas, 8 L of formaldehyde solution, 1 kg of catalyst, 0.3 kg of brown algae oligosaccharide; 3 kg of biochemical potassium fulvic acid, 1 kg of urease inhibitor, 1 kg of nitrification inhibitor, 0.8 kg of chemical reaction controller, and 3 kg of pH regulator.

[0059] In the above preparation process, the first catalyst added to the polymerization reaction was 40% of the total catalyst amount, and the remaining catalyst was added in the second time to obtain liquid fertilizer. Compared with ordinary granular fertilizer, it was compared and applied to corn, soybeans in Northeast China, rice in South China, and summer corn in Central China. The specific experimental results are shown in Table 2.

[0060] Example 3

[0061] The preparation formula is a polymeric liquid fertilizer with a nitrogen content of 240g / L, a phosphorus content of 100g / L, and a potassium content of 120g / L.

[0062] The raw and auxiliary materials used are: 290 kg of granular urea, 230 kg of concentrated liquid phosphoric acid containing 60% phosphorus pentoxide, 290 kg of ammonia water containing 30% nitrogen, 190 kg of potassium chloride powder, 20 kg of fine sulfonated straw powder after fermentation, 20 L of SO3 gas, 10 L of formaldehyde solution, 1.2 kg of catalyst, 0.3 kg of brown algae oligosaccharide; 3 kg of biochemical potassium fulvic acid, 1 kg of urease inhibitor, 1 kg of nitrification inhibitor, 1 kg of chemical reaction controller, and 2 kg of pH regulator.

[0063] In the above preparation process, the first catalyst added to the polymerization reaction is 60% of the total catalyst amount, and the remaining catalyst is added for the second time to obtain liquid fertilizer. This formula is the main formula for one-time fertilization of corn. Compared with ordinary granular fertilizer, it is used for comparative application on corn in Northeast China and summer corn in Central China. The specific experimental results are shown in Table 2.

[0064] Table 2: Experimental results of fertilization effect of liquid fertilizers made with different raw materials

[0065]

[0066] Experimental results show that the present invention, when applied to a variety of crops, eliminates the need for topdressing or other fertilizers throughout the crop's growth cycle. While reducing fertilizer application by 30% to 40% per mu, yield increases can be achieved. The highest yield increases were seen in Northeast China corn and Central China summer corn, exceeding 15%. Furthermore, the present invention can be applied in regions with varying soil properties and seasonal variations, achieving yield-increasing results with reduced fertilizer application.

[0067] Examples 4 to 8 provide five groups of liquid fertilizers of the present invention with different components. Experiments were conducted on two crops, corn in Northeast China and rice in South China, to verify the reasonable range of the formula of the present invention. The following examples are all calculated by weight, and any weight that is insufficient will be supplemented with purified water.

[0068] Example 4

[0069] Component ratio: 35 parts of urea polyphosphate, 55 parts of ammonium polyphosphate, 5 parts of ammonium phosphate, 0.1 parts of potassium chloride or potassium sulfate, 1 part of ammonium sulfate, 0.2 parts of fulvic acid, 0.1 parts of chelated lignin, 0.05 parts of complexed polymerized amino acid small molecule compounds, 0.01 parts of small molecule functional group compounds formed by phosphoric acid, ammonia and lignin, brown algae oligosaccharides, and biochemical fulvic acid, 0.05 parts of urease inhibitors, 0.15 parts of nitrification inhibitors, 0.01 parts of brown algae oligosaccharides, and 5 parts of purified water.

[0070] Example 5

[0071] Component ratio: 30 parts of polyurea phosphate, 40 parts of ammonium polyphosphate, 5 parts of ammonium phosphate, 25 parts of potassium chloride or potassium sulfate, 1.5 parts of ammonium sulfate, 0.15 parts of fulvic acid, 0.2 parts of chelated lignin, 0.1 parts of complexed polymerized amino acid small molecule compounds, 0.02 parts of small molecule functional group compounds formed by phosphoric acid, ammonia and lignin, brown algae oligosaccharides, and biochemical fulvic acid, 0.15 parts of urease inhibitors, 0.05 parts of nitrification inhibitors, and 0.03 parts of brown algae oligosaccharides.

[0072] Example 6

[0073] Component ratio: 35 parts of urea polyphosphate, 40 parts of ammonium polyphosphate, 10 parts of ammonium phosphate, 15 parts of potassium chloride or potassium sulfate, 2 parts of ammonium sulfate, 0.2 parts of fulvic acid, 0.15 parts of chelated lignin, 0.02 parts of complexed polymerized amino acid small molecule compounds, 0.02 parts of small molecule functional group compounds formed by phosphoric acid, ammonia and lignin, brown algae oligosaccharides, and biochemical fulvic acid, 0.1 parts of urease inhibitors, 0.1 parts of nitrification inhibitors, and 0.05 parts of brown algae oligosaccharides.

[0074] Example 7

[0075] Component ratio: 20 parts of urea polyphosphate, 40 parts of ammonium polyphosphate, 10 parts of ammonium phosphate, 30 parts of potassium chloride or potassium sulfate, 1.5 parts of ammonium sulfate, 0.1 part of fulvic acid, 0.15 parts of chelated lignin, 0.05 parts of complexed polymerized amino acid small molecule compounds, 0.01 parts of small molecule functional group compounds formed by phosphoric acid, ammonia and lignin, brown algae oligosaccharides, and biochemical fulvic acid, 0.05 parts of urease inhibitors, 0.05 parts of nitrification inhibitors, and 0.01 parts of brown algae oligosaccharides.

[0076] Example 8

[0077] Component ratio: 40 parts of urea polyphosphate, 35 parts of ammonium polyphosphate, 8 parts of ammonium phosphate, 15 parts of potassium chloride or potassium sulfate, 1 part of ammonium sulfate, 0.1 part of fulvic acid, 0.2 parts of chelated lignin, 0.1 parts of complexed polymerized amino acid small molecule compounds, 0.01 parts of small molecule functional group compounds formed by phosphoric acid, ammonia and lignin, brown algae oligosaccharides, and biochemical fulvic acid, 0.1 parts of urease inhibitors, 0.1 parts of nitrification inhibitors, 0.03 parts of brown algae oligosaccharides, and 2 parts of purified water.

[0078] The specific experimental results are shown in the table below:

[0079] Table 3: Comparison of experimental results under different group ratios

[0080]

[0081] As can be seen from the table above, in experiments conducted on corn in Northeast China and rice in South China, the application of the liquid fertilizer of the present invention in different composition ratios increased yields by more than 10% while reducing the amount of fertilizer applied by more than 36%, compared with the control group using ordinary granular fertilizer. The yield increase of corn in Northeast China was 16.5%, and the yield increase of rice in South China was 11.1%.

[0082] In Example 2, soil samples were taken after planting Northeast corn and South China rice, and the pH value, organic matter, and heavy metals (cadmium and lead) in the soil were detected and compared with those in the control group. The organic matter was detected by potassium dichromate volumetric method, and the heavy metals (cadmium and lead) were detected by the method described in GB / T 17141-1997 "Soil quality - Determination of lead and cadmium - Graphite furnace atomic absorption spectrophotometry".

[0083] The specific results are as follows:

[0084] Table 4: Comparison of soil property test results after cultivation

[0085] Sample type pH Organic matter (g / kg) Cadmium (mg / kg) Lead (mg / kg) Northeast Corn 6.8 56 0.3 120 Control group 2 (Songhuajiang Farm) 7.0 43 0.3 130 South China Rice 6.6 45 0.6 140 Control group 2 (Xiaogang Village) 6.9 35 0.6 130

[0086] It can be seen from the above experimental results that after tillage and harvesting of the soil in different areas where liquid fertilizer was applied, the organic matter content in the soil was higher than that in the control group, and the cadmium content was not significantly different from that in the control group, but the lead content was lower than that in the control group. This shows that the liquid fertilizer of the present invention also has the effect of increasing soil fertility. Long-term use is beneficial to improving soil properties and meeting the sustainable development needs of agriculture.

Claims

1. A method for preparing a stable and synergistic liquid fertilizer containing polyphosphate, comprising: performing a polymerization reaction between liquid phosphoric acid and urea to generate a polyurea phosphate liquid; performing a secondary polymerization between the polyurea phosphate liquid and aqueous ammonia to obtain a first mixed solution of ammonium polyphosphate, ammonium phosphate, and polyurea phosphate; adjusting the pH value to 6.5-7.5; and packaging the mixture to obtain a finished product, characterized in that: After the first mixed solution is generated and before the pH value is adjusted, fermented and sulfonated straw powder is added to the first mixed solution, SO3 is introduced and formaldehyde solution is added dropwise to generate phosphorylated lignin, and a chelation reaction is carried out at room temperature to form a second mixed solution containing chelated lignin and amino acids, a suspending agent is added, and the mixture is fully stirred and mixed; The polymerization reaction and the secondary polymerization reaction are both carried out under the action of a catalyst, wherein the catalyst used is one or a combination of sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and sodium carbonate, and the catalyst dosage is 0.8‰ to 1.2‰; In the polymerization reaction and the secondary polymerization reaction, a chemical reaction controller is used to control the reaction progress, the polymerization degree of the ammonium polyphosphate is controlled to be 9% to 15%, and the dosage of the chemical reaction controller is 0.4‰ to 1.0‰.

2. The method for preparing the stable synergistic liquid fertilizer containing polymeric phosphorus according to claim 1, characterized in that: After the second mixed solution is generated and before the suspending agent is added, biochemical potassium fulvic acid is added to the second mixed solution to carry out a complex reaction to form a third mixed solution containing polymerized amino acids, potassium phosphate, and small molecular compounds of fulvic acid.

3. The method for preparing the stable synergistic liquid fertilizer containing polymeric phosphorus according to claim 1, characterized in that: The particle size of the straw powder is 200 meshes.

4. The method for preparing the stable synergistic liquid fertilizer containing polymeric phosphorus according to claim 1, characterized in that: The concentration of the ammonia water is 30% to 40%, and the liquid phosphoric acid is 45% to 60% concentrated liquid phosphoric acid containing phosphorus pentoxide. During the preparation process, brown algal oligosaccharides, a urease inhibitor, a nitrification inhibitor, potassium chloride or potassium sulfate are added. The urease inhibitor is one or a combination of thiourea and methylphosphoric triamide, and the nitrification inhibitor is one or a combination of dicyandiamide, 2-chloro-methylpyridine and hydroquinone.

5. A liquid fertilizer containing polymeric phosphorus and stabilized synergistically prepared by any one of the preparation methods of claims 1 to 4, characterized in that: The components include, by weight, 20-35 parts of urea polyphosphate, 35-55 parts of ammonium polyphosphate, 5-10 parts of ammonium phosphate, 0.1-30 parts of potassium chloride or potassium sulfate, 1-2 parts of ammonium sulfate, 0.1-0.2 parts of fulvic acid, 0.1-0.2 parts of chelated lignin, 0.02-0.1 parts of complexed polymerized amino acid small molecule compounds, 0.01-0.02 parts of small molecule functional group compounds formed by phosphoric acid, ammonia and lignin, brown algae oligosaccharide and biochemical fulvic acid, 0.05-0.15 parts of urease inhibitors, 0.05-0.15 parts of nitrification inhibitors and 0.01-0.05 parts of brown algae oligosaccharide.

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