Special soil testing formula fertilizer for mountain citrus and preparation method of special soil testing formula fertilizer

Abstract

The invention discloses a special soil testing formula fertilizer for mountain citrus and a preparation method thereof, and belongs to the technical field of fertilizers, the special soil testing formula fertilizer for mountain citrus comprises the following raw materials by weight: 30-40 parts of a nitrogen fertilizer, 11-15 parts of a potassium fertilizer, 11-15 parts of a phosphate fertilizer, 0.2-0.6 part of trace elements, 5-9 parts of a coating material, and 0.1-0.2 part of microcrystalline wax. The special soil testing formula fertilizer for the mountain citrus is prepared by the following steps: putting a nitrogen fertilizer, a potassium fertilizer, a phosphorus fertilizer and trace elements into a rotary drum, preheating to 60-75 DEG C, adding microcrystalline wax, mixing for 40-50 minutes under the condition that the rotating speed is 300-400 r / min, spraying a coating material by using a spray gun in a stirring state, drying the obtained product to constant weight, and cooling to room temperature, thereby obtaining the special soil testing formula fertilizer for the mountain citrus. According to the invention, the auxiliary agent and the diallyl disulfide are added into the coating material, so that the fertilizer has excellent slow release performance.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizers, and in particular relates to a soil testing formula fertilizer special for mountain citrus and a preparation method thereof. Background Art

[0002] Citrus (Latin name: Citrus reticulata Blanco.) belongs to the Rutaceae family. It likes warm and humid climates and is slightly more cold-resistant than grapefruit, sour orange and sweet orange. China is one of the important origins of citrus. It is rich in citrus resources and has a wide variety of fine varieties. It has a cultivation history of more than 4,000 years. Citrus is a treasure from head to toe. Its flesh, peel, core and vein can all be used as medicine. The main active ingredients in citrus are flavonoids, monoterpenes, coumarins, carotenoids, propanols, acridones and glycerol glycolipids. Compared with the world's major citrus producing countries, China's citrus production is large because of its large citrus cultivation area. However, the level of citrus yield per unit area is not high. How to increase citrus yield is one of the key factors to improve the economic benefits of citrus, and fertilization is one of the important measures that are indispensable to increase citrus yield.

[0003] Most citrus orchards are located in mountainous and hilly areas, where the land slope is large and soil and water are easily lost. Citrus fertilization is mainly based on quick-acting fertilizers, which are highly soluble and easy to lose. Not only is the fertilizer utilization rate low, but it also pollutes downstream rivers and lakes. Adult citrus trees undergo physiological changes in germination, shoots, flowering and fruiting in a year. They shoot four times a year in spring, summer, autumn and winter, during which flower bud differentiation and fruit setting are carried out at the same time. Therefore, nutritional regulation of citrus trees is very important. If there is excess nutrition, the branches and shoots will grow too vigorously, causing a large number of flowers and fruits to fall. If there is insufficient nutrition, the branches and fruits will compete for nutrients, causing the fruits to develop poorly. Citrus should be supplied with nutrients continuously and evenly to ensure high and stable yields. Quick-acting fertilizers dissolve quickly and have short fertilizer effects. Unless they are fertilized frequently, they cannot meet the normal growth of citrus. Therefore, it is necessary to prepare a slow-release fertilizer to improve the utilization efficiency of fertilizers, provide nutrients for citrus at all growth stages, and reduce the loss of leaching and volatilization. Summary of the invention

[0004] In order to solve the problem that the prior art quick-acting fertilizers dissolve quickly but have short fertilizer effects and cannot meet the normal growth requirements of citrus unless fertilized frequently, the purpose of the present invention is to provide a soil testing formula fertilizer specifically for mountain citrus and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a soil-testing formula fertilizer specifically for mountain citrus, comprising the following raw materials in parts by weight: 30-40 parts of nitrogen fertilizer, 11-15 parts of potassium fertilizer, 11-15 parts of phosphorus fertilizer, 0.2-0.6 parts of trace elements, 5-9 parts of coating material, and 0.1-0.2 parts of microcrystalline wax; wherein the coating material is obtained by cross-linking and mixing carboxymethyl cellulose, acrylic acid, acrylamide, diallyl disulfide and an auxiliary agent, and the auxiliary agent contains a disulfide bond, a guanidine group, a siloxane chain and sulfur element.

[0007] Furthermore, the nitrogen fertilizer is urea.

[0008] Furthermore, the potash fertilizer is a mixture of one or more of potassium chloride, potassium sulfate and potassium nitrate in any proportion.

[0009] Furthermore, the phosphate fertilizer is one or more of ammonium polyphosphate, sodium hexametaphosphate, and potassium metaphosphate mixed in any proportion.

[0010] Furthermore, the trace elements are combinations of magnesium, sulfur, iron, manganese, boron, zinc, copper and molybdenum compounds in any ratio.

[0011] Furthermore, the preparation method of the coating material is:

[0012] Weigh carboxymethyl cellulose, add deionized water, and stir in a 60°C water bath until completely gelatinized to obtain gelatinized carboxymethyl cellulose; in an ice water bath, drop a 10% sodium hydroxide solution into acrylic acid until the pH value is 6.0, then add gelatinized carboxymethyl cellulose, acrylamide, diallyl disulfide, an auxiliary agent, and deionized water, and stir evenly; add an initiator, potassium persulfate, and a cross-linking agent, N,N-methylenebisacrylamide, and heat to 75°C while stirring at 5°C / min, and perform a constant temperature polymerization reaction for 50-70min to obtain a coating material.

[0013] Among them, the dosage ratio of carboxymethyl cellulose and deionized water is 1g:30mL; the dosage ratio of gelatinized carboxymethyl cellulose, acrylic acid, acrylamide, diallyl disulfide, additives, deionized water, potassium persulfate, and N,N-methylenebisacrylamide is 3g:14g:2.4g:3-5g:3-5g:20-25mL:0.5g:0.6g.

[0014] Carboxymethyl cellulose is a water-soluble cellulose derivative with good water solubility, biodegradability, non-toxicity, salt resistance, renewability, and is cheap and easy to obtain; polyacrylic acid / acrylamide is a class of polymers with water absorption and water retention functions. The coated fertilizers prepared from the above substances have both water retention properties and biodegradability.

[0015] Both diallyl disulfide and the additive contain carbon-carbon double bonds, which can participate in polymerization reactions and form a cross-linked network. Diallyl disulfide contains disulfide bonds. The low-bond energy disulfide bonds can promote the slippage of molecular chains. This property can be used to repair the tearing of the membrane shell caused by the collision of fertilizer particles during the coating process in a timely manner, thereby ensuring the integrity of the coating and improving the controlled release performance of the coated fertilizer. The additive is a ring-opening reaction between the epoxy group in the glycidyloxypropyl-terminated polydimethylsiloxane and the amino group in 4-allylthiosemicarbazide to obtain an intermediate containing a hydroxyl group, which is then reacted with the carboxyl group of guanidine acetate to obtain the additive, which contains siloxane chains, guanidine groups and sulfur elements. The siloxane chain can improve the hydrophobicity of the coating material, thereby improving the controlled release performance of the coated fertilizer; the guanidine group has antibacterial properties and can improve the antibacterial properties of the fertilizer; the sulfur element can promote the growth of citrus and increase the yield of citrus.

[0016] Furthermore, the preparation method of the auxiliary agent is:

[0017] S1: Add glycidyloxypropyl terminated polydimethylsiloxane to acetone and mix evenly, add 4-allylthiosemicarbazide, heat to 70-80°C, react for 6-8h, remove the solvent by rotary evaporation, and dry to obtain an intermediate;

[0018] The usage ratio of glycidyloxypropyl terminated polydimethylsiloxane, acetone and 4-allylthiosemicarbazide is 2.4 mL: 50 mL: 2.6 g.

[0019] S2: Add the intermediate to toluene and mix evenly, add guanidine acetate and p-toluenesulfonic acid, heat to 90°C and react for 4-5h, and distill under reduced pressure to obtain an auxiliary agent.

[0020] Among them, the usage ratio of the intermediate, toluene, guanidine acetate and p-toluenesulfonic acid is 3.6g:50mL:2.4g:0.6g.

[0021] In the above reaction, the epoxy group in the glycidyloxypropyl-terminated polydimethylsiloxane undergoes a ring-opening reaction with the amino group in 4-allylthiosemicarbazide to obtain an intermediate containing a hydroxyl group. The intermediate containing a hydroxyl group then reacts with the carboxyl group of guanidine acetate to obtain an auxiliary agent. The auxiliary agent contains a guanidine group and a carbon-carbon double bond. The guanidine group has a broad-spectrum antibacterial effect, so that the fertilizer not only promotes crop growth but also has a bactericidal effect; the carbon-carbon double bond allows the auxiliary agent to participate in the subsequent polymerization reaction.

[0022] In a second aspect, the present invention provides a method for preparing a soil testing formula fertilizer specifically for mountain citrus, comprising the following steps:

[0023] Place nitrogen fertilizer, potassium fertilizer, phosphorus fertilizer and trace elements in a rotating drum, preheat to 60-75°C, add microcrystalline paraffin, mix at a speed of 300-400r / min for 40-50min, spray the coating material with a spray gun under stirring, dry the product to constant weight, cool to room temperature, and obtain a soil testing formula fertilizer specifically for mountain citrus.

[0024] Beneficial effects of the present invention:

[0025] 1. The coating material for preparing the soil-testing formula fertilizer for mountain citrus of the present invention contains disulfide bonds, sulfur elements, guanidine groups and siloxane chains, which can significantly improve the slow-release performance, antibacterial properties and ability to promote citrus growth of the fertilizer. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Preparation Example 1

[0028] The preparation method of the auxiliary agent in this preparation example is:

[0029] S1: Add 2.4 mL of glycidyloxypropyl-terminated polydimethylsiloxane to 50 mL of acetone and mix well, add 2.6 g of 4-allylthiosemicarbazide, heat to 70°C and react for 6 h, remove the solvent by rotary evaporation, and dry to obtain an intermediate;

[0030] S2: Add 3.6 g of the intermediate into 50 mL of toluene and mix well, add 2.4 g of guanidine acetate and 0.6 g of p-toluenesulfonic acid, heat to 90° C. and react for 4 h, and distill under reduced pressure to obtain an auxiliary agent.

[0031] Preparation Example 2

[0032] The preparation method of the auxiliary agent in this preparation example is:

[0033] S1: Add 2.4 mL of glycidyloxypropyl-terminated polydimethylsiloxane to 50 mL of acetone and mix well, add 2.6 g of 4-allylthiosemicarbazide, heat to 80°C and react for 8 h, remove the solvent by rotary evaporation, and dry to obtain an intermediate;

[0034] S2: Add 3.6 g of the intermediate into 50 mL of toluene and mix well, add 2.4 g of guanidine acetate and 0.6 g of p-toluenesulfonic acid, heat to 90° C. and react for 5 h, and distill under reduced pressure to obtain an auxiliary agent.

[0035] Preparation Example 3

[0036] The preparation method of the auxiliary agent in this preparation example is:

[0037] S1: Add 2.4 mL of glycidyloxypropyl-terminated polydimethylsiloxane to 50 mL of acetone and mix well, add 2.6 g of 4-allylthiosemicarbazide, heat to 75°C and react for 7 h, remove the solvent by rotary evaporation, and dry to obtain an intermediate;

[0038] S2: Add 3.6 g of the intermediate into 50 mL of toluene and mix well, add 2.4 g of guanidine acetate and 0.6 g of p-toluenesulfonic acid, heat to 90° C. and react for 4.5 h, and distill under reduced pressure to obtain an auxiliary agent.

[0039] Preparation Example 4

[0040] The preparation method of the coating material in this preparation example is:

[0041] Weigh 1g of carboxymethyl cellulose, add 30mL of deionized water, and stir in a 60°C water bath until completely gelatinized to obtain gelatinized carboxymethyl cellulose; in an ice water bath, add a 10% sodium hydroxide solution to 14g of acrylic acid until the pH value is 6.0, then add 3g of gelatinized carboxymethyl cellulose, 2.4g of acrylamide, 3g of diallyl disulfide, 3g of the auxiliary agent prepared in Preparation Example 1, and 20mL of deionized water, and stir evenly; add 0.5g of initiator potassium persulfate and 0.6g of cross-linking agent N,N-methylenebisacrylamide, heat to 75°C while stirring at 5°C / min, and perform constant temperature polymerization for 50min to obtain a coating material.

[0042] Preparation Example 5

[0043] The preparation method of the coating material in this preparation example is:

[0044] Weigh 1g of carboxymethyl cellulose, add 30mL of deionized water, and stir in a 60°C water bath until completely gelatinized to obtain gelatinized carboxymethyl cellulose; in an ice water bath, add a 10% sodium hydroxide solution to 14g of acrylic acid until the pH value is 6.0, then add 3g of gelatinized carboxymethyl cellulose, 2.4g of acrylamide, 4g of diallyl disulfide, 4g of the auxiliary agent prepared in Preparation Example 2, and 22mL of deionized water, and stir evenly; add 0.5g of initiator potassium persulfate and 0.6g of cross-linking agent N,N-methylenebisacrylamide, heat to 75°C while stirring at 5°C / min, and perform constant temperature polymerization for 70min to obtain a coating material.

[0045] Preparation Example 6

[0046] The preparation method of the coating material in this preparation example is:

[0047] Weigh 1g of carboxymethyl cellulose, add 30mL of deionized water, and stir in a 60°C water bath until completely gelatinized to obtain gelatinized carboxymethyl cellulose; in an ice water bath, add a 10% sodium hydroxide solution to 14g of acrylic acid until the pH value is 6.0, then add 3g of gelatinized carboxymethyl cellulose, 2.4g of acrylamide, 5g of diallyl disulfide, 5g of the auxiliary agent prepared in Preparation Example 3, and 25mL of deionized water, and stir evenly; add 0.5g of initiator potassium persulfate and 0.6g of cross-linking agent N,N-methylenebisacrylamide, heat to 75°C while stirring at 5°C / min, and perform constant temperature polymerization for 60min to obtain a coating material.

[0048] Comparative Example 1

[0049] Compared with Preparation Example 4, this control example is different in that the auxiliary agent in Preparation Example 4 is removed, and the remaining raw materials and steps are the same as Preparation Example 4.

[0050] Comparative Example 2

[0051] Compared with Preparation Example 4, this comparative example is different in that the diallyl disulfide in Preparation Example 4 is removed, and the remaining raw materials and steps are the same as Preparation Example 4.

[0052] Example 1

[0053] This embodiment provides a soil testing formula fertilizer for mountain citrus, including the following raw materials in parts by weight: 30 parts of nitrogen fertilizer, 11 parts of potassium fertilizer, 11 parts of phosphate fertilizer, 0.2 parts of trace elements, 5 parts of the coating material prepared in Preparation Example 4, and 0.1 parts of microcrystalline wax;

[0054] The preparation method of soil testing formula fertilizer for mountain citrus is:

[0055] Place nitrogen fertilizer, potassium fertilizer, phosphorus fertilizer and trace elements in a rotating drum, preheat to 60°C, add microcrystalline paraffin, mix for 40 minutes at a speed of 300r / min, spray the coating material with a spray gun under stirring, dry the product to constant weight, cool to room temperature, and obtain a soil testing formula fertilizer specifically for mountain citrus.

[0056] The nitrogen fertilizer is urea, the potash fertilizer is potassium chloride, the phosphate fertilizer is ammonium polyphosphate, and the trace elements are zinc oxide, manganese sulfate, and ammonium molybdate in a mass ratio of 1:1:1.

[0057] Example 2

[0058] This embodiment provides a soil testing formula fertilizer for mountain citrus, including the following raw materials in parts by weight: 32.5 parts of nitrogen fertilizer, 12 parts of potassium fertilizer, 12 parts of phosphate fertilizer, 0.3 parts of trace elements, 6 parts of the coating material prepared in Preparation Example 5, and 0.125 parts of microcrystalline wax;

[0059] The preparation method of soil testing formula fertilizer for mountain citrus is:

[0060] Place nitrogen fertilizer, potassium fertilizer, phosphorus fertilizer and trace elements in a rotating drum, preheat to 75°C, add microcrystalline paraffin, mix for 50 minutes at a speed of 400r / min, spray the coating material with a spray gun under stirring, dry the product to constant weight, cool to room temperature, and obtain a soil testing formula fertilizer specifically for mountain citrus.

[0061] The nitrogen fertilizer is urea, the potash fertilizer is potassium chloride, the phosphate fertilizer is ammonium polyphosphate, and the trace elements are zinc oxide, manganese sulfate, and ammonium molybdate in a mass ratio of 1:1:1.

[0062] Example 3

[0063] This embodiment provides a soil testing formula fertilizer for mountain citrus, including the following raw materials in parts by weight: 35 parts of nitrogen fertilizer, 13 parts of potassium fertilizer, 13 parts of phosphate fertilizer, 0.4 parts of trace elements, 7 parts of the coating material prepared in Preparation Example 6, and 0.15 parts of microcrystalline wax;

[0064] The preparation method of soil testing formula fertilizer for mountain citrus is:

[0065] Place nitrogen fertilizer, potassium fertilizer, phosphorus fertilizer and trace elements in a rotating drum, preheat to 70°C, add microcrystalline paraffin, mix at a speed of 350r / min for 45 minutes, spray the coating material with a spray gun under stirring, dry the product to constant weight, cool to room temperature, and obtain a soil testing formula fertilizer specifically for mountain citrus.

[0066] The nitrogen fertilizer is urea, the potash fertilizer is potassium chloride, the phosphate fertilizer is ammonium polyphosphate, and the trace elements are zinc oxide, manganese sulfate, and ammonium molybdate in a mass ratio of 1:1:1.

[0067] Example 4

[0068] This embodiment provides a soil testing formula fertilizer for mountain citrus, including the following raw materials in parts by weight: 37.5 parts of nitrogen fertilizer, 14 parts of potassium fertilizer, 14 parts of phosphorus fertilizer, 0.5 parts of trace elements, 8 parts of the coating material prepared in Preparation Example 6, and 0.175 parts of microcrystalline wax;

[0069] The preparation method of soil testing formula fertilizer for mountain citrus is:

[0070] Place nitrogen fertilizer, potassium fertilizer, phosphorus fertilizer and trace elements in a rotating drum, preheat to 70°C, add microcrystalline paraffin, mix at a speed of 350r / min for 45 minutes, spray the coating material with a spray gun under stirring, dry the product to constant weight, cool to room temperature, and obtain a soil testing formula fertilizer specifically for mountain citrus.

[0071] The nitrogen fertilizer is urea, the potash fertilizer is potassium chloride, the phosphate fertilizer is ammonium polyphosphate, and the trace elements are zinc oxide, manganese sulfate, and ammonium molybdate in a mass ratio of 1:1:1.

[0072] Example 5

[0073] This embodiment provides a soil testing formula fertilizer for mountain citrus, including the following raw materials in parts by weight: 40 parts of nitrogen fertilizer, 15 parts of potassium fertilizer, 15 parts of phosphate fertilizer, 0.6 parts of trace elements, 9 parts of the coating material prepared in Preparation Example 6, and 0.2 parts of microcrystalline wax;

[0074] The preparation method of soil testing formula fertilizer for mountain citrus is:

[0075] Place nitrogen fertilizer, potassium fertilizer, phosphorus fertilizer and trace elements in a rotating drum, preheat to 70°C, add microcrystalline paraffin, mix at a speed of 350r / min for 45 minutes, spray the coating material with a spray gun under stirring, dry the product to constant weight, cool to room temperature, and obtain a soil testing formula fertilizer specifically for mountain citrus.

[0076] The nitrogen fertilizer is urea, the potash fertilizer is potassium chloride, the phosphate fertilizer is ammonium polyphosphate, and the trace elements are zinc oxide, manganese sulfate, and ammonium molybdate in a mass ratio of 1:1:1.

[0077] Comparative Example 1

[0078] The difference between this comparative example 1 and example 1 is that the coating material in example 1 is replaced by the product in control example 1, and the other raw materials and steps are the same as example 1.

[0079] Comparative Example 2

[0080] The difference between this comparative example 1 and example 1 is that the coating material in example 1 is replaced by the product in comparative example 2, and the other raw materials and steps are the same as example 1.

[0081] The performance tests were performed on the fertilizers prepared in Examples 1 to 5 and Comparative Examples 1 and 2. The test items were as follows:

[0082] 1. Slow-release experiment of fertilizer: Determine by water dissolution rate method according to GB / T 23348-2009; weigh 10g of fertilizer prepared in Example 1-Example 5 and Comparative Example 1-Comparative Example 2 and put it into a small bag made of 100-mesh nylon mesh, put the small bag into a 250mL glass bottle, add 200mL water, cover and seal, place in a 25°C biochemical constant temperature incubator, take samples at 1, 15, 30, 45, and 65 days, test the nitrogen release amount by automatic analyzer, calculate the cumulative nitrogen release rate, and the calculation formula is as follows: nitrogen release rate=Wn / W, where Wn is the mass fraction of nitrogen release measured on the nth day, and W is the mass fraction of total nitrogen. The test results are shown in Table 1.

[0083] 2. Citrus fertilization experiment: The application rate of fertilizer for each treatment was 1100 kg / mu, and 300, 300 and 500 kg / mu were applied in March, July and November of each year respectively. The amount of fertilizer, fertilization method and other cultivation management measures were consistent. The citrus trees for the test were 6 years old, with a row spacing of 4m×4m, and a planting density of 40 trees / mu. The random block arrangement was 3 replicates per treatment, and each replicate was 64m 2 , detect the incidence of citrus black spot disease, incidence = (number of diseased plants / total number of plants) × 100%, after harvesting, count and calculate the per-acre yield of citrus, the test results are shown in Table 2.

[0084] Table 1

[0085] project 1d dissolution rate 15d dissolution rate 30d dissolution rate 45d dissolution rate 65d dissolution rate Example 1 1.04％ 8.27％ 34.45％ 73.21％ 93.72％ Example 2 1.03％ 8.28％ 34.42％ 73.19％ 93.68％ Example 3 1.01％ 8.26％ 34.43％ 73.24％ 93.71％ Example 4 0.99％ 8.24％ 34.40％ 73.23％ 93.66％ Example 5 0.97％ 8.19％ 34.38％ 73.26％ 93.61％ Comparative Example 1 4.31％ 13.20％ 58.48％ 89.42％ 100％ Comparative Example 2 3.98％ 12.71％ 57.22％ 87.19％ 100％

[0086] It can be seen from Table 1 that within the same period of time, the slow-release performance of the fertilizers of Examples 1 to 5 is better than that of Comparative Examples 1 and 2.

[0087] Table 2

[0088] project Incidence / % Yield per mu (kg / mu) Example 1 1.14 912.7 Example 2 1.11 923.4 Example 3 1.02 928.5 Example 4 0.99 931.4 Example 5 0.98 937.0 Comparative Example 1 43.18 875.3 Comparative Example 2 1.18 890.4

[0089] It can be seen from Table 2 that the fertilizers prepared in Examples 1 to 5 can effectively prevent and treat citrus black spot disease and increase the per-acre yield of citrus.

[0090] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0091] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A soil testing formula fertilizer specially used for mountain citrus, characterized in that: The invention comprises the following raw materials in parts by weight: 30-40 parts of nitrogen fertilizer, 11-15 parts of potash fertilizer, 11-15 parts of phosphate fertilizer, 0.2-0.6 parts of trace elements, 5-9 parts of coating material and 0.1-0.2 parts of microcrystalline wax; wherein the coating material is obtained by cross-linking and mixing carboxymethyl cellulose, acrylic acid, acrylamide, diallyl disulfide and an auxiliary agent, and the auxiliary agent contains a disulfide bond, a guanidine group, a siloxane chain and sulfur element.

2. The soil testing formula fertilizer for mountain citrus according to claim 1, characterized in that: The nitrogen fertilizer is urea.

3. The soil testing formula fertilizer for mountain citrus according to claim 1, characterized in that: Potash fertilizer is a mixture of one or more of potassium chloride, potassium sulfate and potassium nitrate in any proportion.

4. The soil testing formula fertilizer for mountain citrus according to claim 1, characterized in that: The phosphate fertilizer is one or more of ammonium polyphosphate, sodium hexametaphosphate and potassium metaphosphate mixed in any proportion.

5. The soil testing formula fertilizer for mountain citrus according to claim 1, characterized in that: The trace elements are combinations of magnesium, sulfur, iron, manganese, boron, zinc, copper and molybdenum compounds in any ratio.

6. The soil testing formula fertilizer for mountain citrus according to claim 1, characterized in that: The preparation method of the coating material is as follows: Weigh carboxymethyl cellulose, add deionized water, and stir in a 60°C water bath until completely gelatinized to obtain gelatinized carboxymethyl cellulose; in an ice water bath, drop a 10% sodium hydroxide solution into acrylic acid until the pH value is 6.0, then add gelatinized carboxymethyl cellulose, acrylamide, diallyl disulfide, an auxiliary agent, and deionized water, and stir evenly; add potassium persulfate and N,N-methylenebisacrylamide, heat to 75°C while stirring at 5°C / min, and perform a constant temperature polymerization reaction for 50-70 minutes to obtain a coating material.

7. A soil testing formula fertilizer for mountain citrus according to claim 6, characterized in that: The dosage ratio of carboxymethyl cellulose and deionized water is 1g:30mL; the dosage ratio of gelatinized carboxymethyl cellulose, acrylic acid, acrylamide, diallyl disulfide, additives, deionized water, potassium persulfate, and N,N-methylenebisacrylamide is 3g:14g:2.4g:3-5g:3-5g:20-25mL:0.5g:0.6g.

8. The soil testing formula fertilizer for mountain citrus according to claim 6, characterized in that: The preparation method of the auxiliary agent is: S1: Add glycidyloxypropyl terminated polydimethylsiloxane to acetone and mix evenly, add 4-allylthiosemicarbazide, heat to 70-80°C, react for 6-8h, rotary evaporate, and dry to obtain an intermediate; S2: Add the intermediate to toluene and mix evenly, add guanidine acetate and p-toluenesulfonic acid, heat to 90°C and react for 4-5h, and distill under reduced pressure to obtain an auxiliary agent.

9. A soil testing formula fertilizer for mountain citrus according to claim 8, characterized in that: In step S1, the usage ratio of glycidyloxypropyl-terminated polydimethylsiloxane, acetone, and 4-allylthiosemicarbazide is 2.4 mL: 50 mL: 2.6 g; in step S2, the usage ratio of the intermediate, toluene, guanidine acetate, and p-toluenesulfonic acid is 3.6 g: 50 mL: 2.4 g: 0.6 g.

10. The method for preparing a soil testing formula fertilizer specifically for mountain citrus according to any one of claims 1 to 9, characterized in that: The following steps are involved: Place nitrogen fertilizer, potassium fertilizer, phosphorus fertilizer and trace elements in a rotating drum, preheat to 60-75°C, add microcrystalline paraffin, mix at a speed of 300-400r / min for 40-50min, spray the coating material with a spray gun under stirring, dry the product to constant weight, cool to room temperature, and obtain a soil testing formula fertilizer specifically for mountain citrus.