Urea and urease / nitrification inhibitor synchronous slow-release type special nitrogen fertilizer for winter wheat as well as preparation method and application thereof

Abstract

The invention discloses a urea and urease / nitrification inhibitor synchronous slow release type special nitrogen fertilizer for winter wheat as well as a preparation method and application thereof, and belongs to the technical field of slow and controlled release fertilizer production. The urea, the urease / nitrification inhibitor, the plant fibers and the modified biochemical fulvic acid are pelletized and then coated, the raw materials are cheap, easy to obtain and environmentally friendly, the plant fibers and the modified biochemical fulvic acid can regulate slow release of the urease / nitrification inhibitor and have a synergistic effect on the urea, release and conversion of nitrogen are adjusted in a long-acting mode, and the nitrogen-rich fertilizer has a good application prospect. The release synchronism of nitrogen and the inhibitor is greatly improved. According to the fertilizer nutrient release characteristics and the winter wheat fertilizer requirement rule, synergistic coated fertilizers are added in different controlled release periods to be blended to prepare the winter wheat synchronous nutrition blended fertilizer, and topdressing is not needed when the fertilizer is applied once before sowing.

Description

Technical Field

[0001] The invention relates to the technical field of slow-release fertilizer production, and in particular to a urea and urease / nitrification inhibitor synchronous slow-release type nitrogen fertilizer specifically for winter wheat, and a preparation method and application thereof. Background Art

[0002] Winter wheat is one of the most important food crops in my country, accounting for more than 90% of the country's wheat production. By 2023, the area of ​​winter wheat in my country will exceed 330 million mu, accounting for nearly one-third of the country's cultivated land. Therefore, achieving stable and high yields of wheat more efficiently is an important direction to ensure the country's food supply and realize the intelligent development of agriculture. There are rich types of fertilizers, containing various fast-acting nutrients, which can quickly supply crop growth after being applied to the soil, making a huge contribution to agricultural development. Traditional fertilizers release nutrients quickly, not only requiring topdressing, but also farmers often have problems such as large usage and unreasonable fertilization structure in pursuit of higher yields. This will not only cause nutrient loss and waste of resources, but may also increase the risk of environmental pollution.

[0003] In order to reduce nutrient loss and make fertilizer nutrient release more reasonable, slow-release fertilizers and stable fertilizers came into being. Slow-release fertilizers generally extend the nutrient release period and reduce nutrient loss by coating. However, the nutrient release of a single controlled-release fertilizer is usually difficult to match the nutrient demand of crops during their growth period; in addition, traditional controlled-release fertilizers can only control the dissolution of nitrogen and cannot further control nitrogen conversion.

[0004] Stable fertilizers with added urease / nitrification inhibitors can regulate the conversion of nitrogen in the soil, thereby reducing nutrient losses and improving nutrient utilization. However, in actual applications, the effective period of inhibitors is affected by many factors such as soil type, ambient temperature, moisture conditions, and soil microbial activity, and there is great uncertainty. Taking NBPT as an example, the half-life of NBPT in non-sterile soil is 4.8-7.6 days, and the actual action time is generally no more than three weeks. Therefore, from the perspective of fertilizer preparation, extending the effective period of inhibitors and increasing the synchronous release rate of urea and inhibitors are of great significance to the intelligent and sustainable development of controlled-release fertilizers.

[0005] In order to improve the synchronization of the release of urea and urease / nitrification inhibitors, the existing technology combines the coating with the inhibitor to develop a dual-control urea coated with a thermosetting epoxy resin and a urease / nitrification inhibitor coating, thereby achieving dual control of the release of urea and inhibitors; however, the consistency of the release rate of urease / nitrification inhibitors and urea still needs to be further improved. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a urea and urease / nitrification inhibitor synchronous slow-release type winter wheat special nitrogen fertilizer and its preparation method and application. The present invention uses plant fiber, modified biochemical fulvic acid and silica fume modified polyvinyl alcohol to granulate with urea, urease inhibitor and nitrification inhibitor, and then performs coating treatment, which greatly improves the synchronization of nitrogen and inhibitor release.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect of the present invention, a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer is provided, which is prepared by the following method:

[0009] (1) mixing urea, urease inhibitor, nitrification inhibitor, plant fiber and modified biochemical fulvic acid in a weight ratio of 100:(0.1-5):(0.4-5):(3-12):(4-15) to obtain a synergistic fertilizer powder; mixing the synergistic fertilizer powder with silica fume modified polypropylene alcohol to obtain synergistic fertilizer granules;

[0010] (2) The synergistic fertilizer particles are coated to prepare a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer.

[0011] Preferably, in step (1), the plant fiber is selected from one or more of wood fiber, bamboo fiber, flax fiber, sisal fiber and coconut fiber.

[0012] The above-mentioned plant fibers have the advantages of wide sources, low prices, and being green and environmentally friendly; and can also play a role in increasing the strength of fertilizer particles.

[0013] Preferably, in step (1), the modified biochemical fulvic acid is prepared by the following method:

[0014] Mix the biochemical fulvic acid, acetone and silane coupling agent in the ratio of (3-6) g: (12-36) ml: (2-9) ml, filter, dry and grind the residue.

[0015] More preferably, the silane coupling agent is selected from one or more of γ-methacryloxypropyltrimethoxysilane, 3-(2,3-epoxypropyloxy)propyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0016] Biochemical fulvic acid has a growth-promoting effect on crops, but it has strong hydrophilicity and poor compatibility with other substances. The present invention uses acetone and silane coupling agent to modify it, thereby increasing its water resistance and compatibility with various raw materials.

[0017] Preferably, in step (1), the silica fume modified polypropylene alcohol is prepared by the following method:

[0018] Put polyvinyl alcohol in a water bath at 85℃-95℃ until it is completely dissolved, add silica fume and inorganic acid, stir evenly, and then perform ultrasonic treatment and degassing to obtain silica fume modified polyvinyl alcohol;

[0019] The ratio of the added amounts of polyvinyl alcohol, silica fume and inorganic acid is (3-7) g: (2-5) g: (12-35) ml.

[0020] More preferably, the inorganic acid is hydrochloric acid, sulfuric acid or nitric acid with a mass fraction of 5-16%.

[0021] The invention utilizes silica fume and inorganic acid to modify polyvinyl alcohol, thereby adjusting its viscosity and enhancing its water resistance.

[0022] Preferably, in step (1), the mass ratio of the synergistic fertilizer powder to the silica fume modified polyvinyl alcohol is 100:(2-7).

[0023] Preferably, in step (1), the urease inhibitor includes: phosphoramide inhibitors such as N-butylthiophosphoric triamide (NBPT), cycloethylphosphoric triamide (CNPT), thiophosphoric triamide (TPT), phosphoric triamide (PT) and phenolic quinone compounds such as 1,4-hydroquinone (hydroquinone, HQ).

[0024] The nitrification inhibitors include 3,4-dimethylpyrazole phosphate (DMPP), dicyandiamide (DCD), and 2-chloro-6-trichloromethylpyridine (NP).

[0025] Preferably, in step (2), epoxy resin, polyurethane or other coating materials are used for coating treatment, and the amount of the coating material is 3-7% of the weight of the synergistic fertilizer particles.

[0026] When coating with coating materials, a curing agent, such as triethylenetetramine, is generally added at the same time to shorten the curing time and enhance the stability and durability of the coating material.

[0027] By adjusting the amount of coating material, urea and urease / nitrification inhibitor synchronous slow-release nitrogen fertilizers with different controlled-release periods can be prepared. For example, when the amount of coating material is 4% of the weight of the synergistic fertilizer granules, a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled-release period of 60 days can be prepared; when the amount of coating material is 6% of the weight of the synergistic fertilizer granules, a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled-release period of 90 days can be prepared.

[0028] The second aspect of the present invention provides a one-time application winter wheat synchronous nutrient blended fertilizer, which is obtained by blending urea, a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of 60 days, and a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of 90 days.

[0029] Preferably, the weight ratio of urea, urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of 60 days, and urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of 90 days is (3-4): (1-3): (4-5).

[0030] The one-time application type winter wheat synchronous nutrition blended fertilizer of the present invention reasonably compounds urea with urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizers with different controlled-release periods, so that the release characteristics of the nitrogen fertilizer match the nutritional requirements of wheat, and no topdressing is required after one application before sowing.

[0031] Beneficial effects of the present invention:

[0032] 1. The present invention granulates urea, urease / nitrification inhibitor, plant fiber and modified biochemical fulvic acid and then performs coating. The raw materials are cheap and readily available, and are green and environmentally friendly. The plant fiber and modified biochemical fulvic acid can regulate the slow release of urease / nitrification inhibitor, synergistically enhance the effect of urea, regulate the release and conversion of nitrogen in a long term, and greatly improve the synchronization of nitrogen and inhibitor release.

[0033] 2. The silica fume modified polyvinyl alcohol solution used in the present invention has a simple preparation method, is naturally degradable, has good water resistance and viscosity, and can increase the compatibility of various components; the plant fiber used is low-priced and widely available, and can be combined with polyvinyl alcohol to greatly increase the particle strength and improve the granulation and coating effects of the fertilizer.

[0034] 3. According to the fertilizer nutrient release characteristics and winter wheat fertilizer requirement law, the present invention mixes the internally added synergistic coated fertilizers with different controlled release periods to prepare winter wheat synchronous nutrient blended fertilizers, which can be applied once before sowing without topdressing. Compared with single coated fertilizers, under the same film material input, the nitrogen fertilizer release characteristics are more in line with crop needs, the yield is higher, and the raw material ratio can be adjusted according to the environment and crop needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 : Scanning electron microscope images of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared by the present invention; in the figure, (a) is a surface electron microscope image of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1; (b) is a surface electron microscope image of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 3; (A) is a cross-sectional electron microscope image of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1; (B) is a cross-sectional electron microscope image of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 3.

[0036] Figure 2 : The nitrogen release rate measurement results of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared by the present invention.

[0037] Figure 3 : The nitrogen cumulative release rate measurement results of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared by the present invention.

[0038] Figure 4 : The cumulative release rate of nitrogen and inhibitor of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1 of the present invention was measured.

[0039] Figure 5 : Soil available nitrogen content and wheat nitrogen uptake in each treatment group at different growth stages of wheat. DETAILED DESCRIPTION

[0040] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0041] As mentioned above, in order to improve the conversion and utilization efficiency of nitrogen, one of the currently used methods is to use nitrogen fertilizer together with urease / nitrification inhibitors. However, the urease / nitrification inhibitors have a short time to work in the soil and are difficult to release synchronously with urea. In the previous study, the inventors mixed the urease / nitrification inhibitors and coated the urea fertilizer core, and then coated it. The coating reduced the dissolution rate of the inhibitors, but the coating effect and the synchronous release performance of nitrogen and the inhibitors still need to be further improved.

[0042] Based on this, the present invention utilizes plant fiber, modified biochemical fulvic acid and silica fume modified polyvinyl alcohol to granulate with urea, urease inhibitor and nitrification inhibitor, and then performs coating treatment, which greatly improves the synchronization of nitrogen and inhibitor release.

[0043] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0044] The test materials used in the examples and comparative examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels. The experimental methods without detailed conditions are carried out in accordance with conventional test methods or the operating instructions recommended by the supplier. Among them:

[0045] Silica ash, also known as silicon micropowder or ultrafine silicon dioxide powder, is obtained by collecting and treating the smoke and dust emitted from the exhaust gas during the high-temperature smelting of industrial silicon and ferrosilicon in an industrial electric furnace. The silica ash of the present invention was purchased from Henan Zhuangwei New Materials Co., Ltd. Biochemical fulvic acid was purchased from Shandong Yousuo Chemical Technology Co., Ltd.; sisal fiber was purchased from Zhejiang Lafite Paper Products Co., Ltd.

[0046] The modified biochemical fulvic acid is prepared by the following method:

[0047] 5 g of biochemical fulvic acid, 30 ml of acetone and 5 ml of silane coupling agent (3-aminopropyltriethoxysilane) were mixed evenly, filtered, dried at 60° C. and then ground to obtain modified biochemical fulvic acid.

[0048] Silica fume modified polypropylene alcohol is prepared by the following method:

[0049] Take 5g of polyvinyl alcohol and add water to 100ml, stir and dissolve in a 90℃ water bath for 1.5h, then add 3g of silica ash and 25ml of 8% hydrochloric acid, stir evenly, and then treat with ultrasound for 2h to remove bubbles, to obtain silica ash modified polyvinyl alcohol.

[0050] Example 1: Preparation of urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer

[0051] (1) Urea, 1,4-hydroquinone (HQ), dicyandiamide (DCD), sisal fiber and modified biochemical fulvic acid are ground and sieved (100 meshes) respectively, and then mixed in a weight ratio of urea: DCD: HQ: sisal fiber: modified biochemical fulvic acid = 100: 0.8: 3.9: 4: 10 to obtain a synergistic fertilizer powder.

[0052] (2) Add the synergistic fertilizer powder into a drum granulator, spray 3% by mass of silica fume modified polypropylene alcohol into the synergistic fertilizer powder for mixing and granulation, until most of the particles in the drum are wrapped to more than 2 mm, then take them all out, and sieve out fertilizer particles with a particle diameter of 2-5 mm. Place the sieved fertilizer particles in a drying oven and dry them at 75° C. for 6 hours to obtain synergistic fertilizer particles.

[0053] (3) Add 1 kg of synergistic fertilizer granules into a drum coating machine and heat to 75°C, take 10 g of epoxy resin preheated to 85°C, add 2 g of triethylenetetramine curing agent, mix well and spray onto the fertilizer surface, continue heating to allow the coating liquid to wrap around the fertilizer surface and solidify, repeat 3 times, and obtain a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of about 60 days.

[0054] Example 2: Preparation of urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer

[0055] (1) Urea, 1,4-hydroquinone (HQ), dicyandiamide (DCD), sisal fiber and modified biochemical fulvic acid are ground and sieved (100 meshes) respectively, and then mixed in a weight ratio of urea: DCD: HQ: sisal fiber: modified biochemical fulvic acid = 100: 0.8: 3.9: 4: 10 to obtain a synergistic fertilizer powder.

[0056] (2) Add the synergistic fertilizer powder into a drum granulator, spray 3% by mass of silica fume modified polypropylene alcohol into the synergistic fertilizer powder for mixing and granulation, until most of the particles in the drum are wrapped to more than 2 mm, then take them all out, and sieve out fertilizer particles with a particle diameter of 2-5 mm. Place the sieved fertilizer particles in a drying oven and dry them at 75° C. for 6 hours to obtain synergistic fertilizer particles.

[0057] (3) 1 kg of synergistic fertilizer granules were added into a drum coating machine and heated to 75°C. 10 g of epoxy resin preheated to 85°C was added with 2 g of triethylenetetramine curing agent. The mixture was mixed and sprayed onto the fertilizer surface. The coating liquid was then heated to solidify on the fertilizer surface. The process was repeated 5 times to obtain a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of about 90 days.

[0058] Example 3: Preparation of urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer

[0059] (1) Urea, N-butylthiophosphoric acid triamide (NBPT), 3,4-dimethylpyrazole phosphate (DMPP), sisal fiber and modified biochemical fulvic acid are ground and sieved (100 mesh) respectively, and then mixed in a weight ratio of urea: NBPT: DMPP: sisal fiber: modified biochemical fulvic acid = 100: 0.25: 0.5: 7: 11 to obtain a synergistic fertilizer powder.

[0060] (2) Add the synergistic fertilizer powder into a drum granulator, spray 3% by mass of silica fume modified polypropylene alcohol into the synergistic fertilizer powder for mixing and granulation, until most of the particles in the drum are wrapped to more than 2 mm, then take them all out, and sieve out fertilizer particles with a particle diameter of 2-5 mm. Place the sieved fertilizer particles in a drying oven and dry them at 75° C. for 6 hours to obtain synergistic fertilizer particles.

[0061] (3) 1 kg of synergistic fertilizer granules were added into a drum coating machine and heated to 65°C. 10 g of polyurethane prepared from polyether polyol and diphenylmethane diisocyanate in a mass ratio of 1:1 was taken and mixed and sprayed onto the surface of the fertilizer. The coating liquid was then coated on the surface of the fertilizer and solidified by continuing to heat. The process was repeated three times to obtain a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of about 60 days.

[0062] Example 4: Preparation of urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer

[0063] (1) Urea, N-butylthiophosphoric acid triamide (NBPT), 3,4-dimethylpyrazole phosphate (DMPP), sisal fiber and modified biochemical fulvic acid are ground and sieved (100 mesh) respectively, and then mixed in a weight ratio of urea: NBPT: DMPP: sisal fiber: modified biochemical fulvic acid = 100: 0.25: 0.5: 7: 11 to obtain a synergistic fertilizer powder.

[0064] (2) Add the synergistic fertilizer powder into a drum granulator, spray 3% by mass of silica fume modified polypropylene alcohol into the synergistic fertilizer powder for mixing and granulation, until most of the particles in the drum are wrapped to more than 2 mm, then take them all out, and sieve out fertilizer particles with a particle diameter of 2-5 mm. Place the sieved fertilizer particles in a drying oven and dry them at 75° C. for 6 hours to obtain synergistic fertilizer particles.

[0065] (3) 1 kg of synergistic fertilizer granules were added into a drum coating machine and heated to 65°C. 10 g of polyurethane prepared from polyether polyol and diphenylmethane diisocyanate in a mass ratio of 1:1 was taken and mixed and sprayed onto the surface of the fertilizer. The coating liquid was then coated on the surface of the fertilizer and solidified. The process was repeated 5 times to obtain a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of about 90 days.

[0066] Example 5: Preparation of one-time application type winter wheat synchronous nutrient fertilizer (3-1-5)

[0067] Urea, the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1, and the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 2 were mixed in a weight ratio of 3:1:5 to prepare a one-time application type winter wheat synchronous nutrient fertilizer.

[0068] Example 6: Preparation of one-time application type winter wheat synchronous nutrient fertilizer (4-2-4)

[0069] Urea, the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1, and the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 2 were mixed in a weight ratio of 7:3:10 to prepare a one-time application type winter wheat synchronous nutrient fertilizer.

[0070] Example 7: Preparation of one-time application type winter wheat synchronous nutrient fertilizer (4-3-5)

[0071] Urea, the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1, and the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 2 were mixed in a weight ratio of 4:3:5 to prepare a one-time application type winter wheat synchronous nutrient fertilizer.

[0072] Example 8: Preparation of one-time application type winter wheat synchronous nutrient fertilizer (3-2-5)

[0073] Urea, the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1, and the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 2 were mixed in a weight ratio of 3:2:5 to prepare a one-time application type winter wheat synchronous nutrient fertilizer.

[0074] Comparative Example 1:

[0075] (1) Urea, 1,4-hydroquinone (HQ), and dicyandiamide (DCD) are ground and sieved (100 meshes) respectively, and then mixed in a weight ratio of urea: HQ: DCD = 100: 0.8: 3.9 to obtain a synergistic fertilizer powder.

[0076] (2) Add the synergistic fertilizer powder into a drum granulator, spray 3% by mass of polypropylene alcohol into the synergistic fertilizer powder for mixing and granulation, until most of the particles in the drum are wrapped to more than 2 mm, then take out all of them, and sieve out fertilizer particles with a particle diameter of 2-5 mm. Place the sieved fertilizer particles in a drying oven and dry them at 75° C. for 6 hours to obtain synergistic fertilizer particles.

[0077] (3) Add 1 kg of synergistic fertilizer granules into a drum coating machine and heat to 75°C. Take 10 g of epoxy resin preheated to 85°C and add 2 g of triethylenetetramine curing agent. Mix well and spray onto the fertilizer surface. Continue heating to allow the coating liquid to solidify on the fertilizer surface. Repeat this process three times to obtain Fertilizer A.

[0078] Comparative Example 2:

[0079] (1) Urea, 1,4-hydroquinone (HQ), dicyandiamide (DCD) and modified biochemical fulvic acid are ground and sieved (100 meshes) respectively, and then mixed in a weight ratio of urea: HQ: DCD: modified biochemical fulvic acid = 100: 0.8: 3.9: 10 to obtain a synergistic fertilizer powder.

[0080] (2) Add the synergistic fertilizer powder into a drum granulator, spray 3% by mass of silica fume modified polypropylene alcohol into the synergistic fertilizer powder for mixing and granulation, until most of the particles in the drum are wrapped to more than 2 mm, then take them all out and sieve out fertilizer particles with a particle diameter of 2-5 mm. Place the sieved fertilizer particles in a drying oven and dry them at 75°C for 6 hours to obtain synergistic fertilizer particles.

[0081] (3) Add 1 kg of synergistic fertilizer granules into a drum coating machine and heat to 75°C. Take 10 g of epoxy resin preheated to 85°C and add 2 g of triethylenetetramine curing agent. Mix well and spray onto the fertilizer surface. Continue heating to allow the coating liquid to solidify on the fertilizer surface. Repeat this process three times to obtain Fertilizer B.

[0082] Comparative Example 3:

[0083] (1) Urea, 1,4-hydroquinone (HQ), dicyandiamide (DCD) and sisal fiber are ground and sieved (100 meshes) respectively, and then mixed in a weight ratio of urea:DCD:HQ:sisal fiber=100:0.8:3.9:4 to obtain a synergistic fertilizer powder.

[0084] (2) Add the synergistic fertilizer powder into a drum granulator, spray 3% by mass of silica fume modified polypropylene alcohol into the synergistic fertilizer powder for mixing and granulation, until most of the particles in the drum are wrapped to more than 2 mm, then take them all out, and sieve out fertilizer particles with a particle diameter of 2-5 mm. Place the sieved fertilizer particles in a drying oven and dry them at 75° C. for 6 hours to obtain synergistic fertilizer particles.

[0085] (3) Add 1 kg of synergistic fertilizer granules into a drum coating machine and heat to 75°C. Take 10 g of epoxy resin preheated to 85°C and add 2 g of triethylenetetramine curing agent. Mix well and spray onto the fertilizer surface. Continue heating to allow the coating liquid to wrap around the fertilizer surface and solidify. Repeat this process three times to obtain Fertilizer C.

[0086] Test Example 1:

[0087] After the granulation stage was completed, the granulation rates of Comparative Examples 1-3 and Example 1 were calculated; after the coating was completed, the actual coating rate was calculated, and then 10 qualified particles were selected from each treatment, and the compressive strength was measured using a particle strength tester (YHKC-2A). The measurement results are shown in Table 1.

[0088] Table 1: Results of granulation rate, actual coating rate and compressive strength

[0089] Experimental Group Granulation rate (%) Actual encapsulation rate (%) Compressive strength(N) Comparative Example 1 60.19±1.62 45.75±0.9 22.25±1.73 Comparative Example 2 70.31±1.12 59.55±1.24 32.04±1.72 Comparative Example 3 76.46±1.33 72.11±1.36 51.96±1.43 Example 1 88.46±1.07 90.5±1.43 61.57±3.45

[0090] The results show that the addition of modified biochemical fulvic acid and sisal fiber to nitrogen fertilizer and urease / nitrification inhibitor has a synergistic effect on improving the granulation rate and coating rate of granulation.

[0091] Test Example 2:

[0092] The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizers prepared in Examples 1 and 3 were observed under a scanning electron microscope (JSM-6610LV, Japan). The results showed that: Figure 1 From the surface images (a, b), it can be seen that the surface of the coated fertilizer is smooth and flat, without obvious pits and protrusions; Figure 1 From the cross-sectional views (A, B), it can be seen that the urease / nitrification inhibitor is combined with sisal fiber and modified biochemical fulvic acid for granulation and then coated. The membrane shell is completely wrapped with uniform thickness and fits tightly to the synergistic urea core without obvious pores.

[0093] Test Example 3:

[0094] The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Examples 1-4 was extracted under static water conditions at 25°C to determine the release rate and cumulative release rate of nitrogen. Figure 2-Figure 3 , as shown in Table 2.

[0095] Table 2: Determination of nitrogen cumulative release rate of coated urea in different embodiments at 25°C static water extraction Unit: %

[0096]

[0097] The results show that the nitrogen release rate of the coated fertilizer prepared by the method of the present invention is about 0.79-3.5% in 24 hours, the nitrogen release rate of Example 1 and Example 3 in 60 days is less than 80%, and the release rate of Example 2 and Example 4 in 90 days is less than 80%. The above results show that fertilizers with different controlled release periods can be prepared by adjusting the coating amount, and can be customized according to the environment and crops.

[0098] Test example 4:

[0099] The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1 was placed in a plastic box at a dosage of 0.6 g N / kg soil and cultured in the soil at 25° C. to detect the cumulative release rate and synchronization of nitrogen and the inhibitor;

[0100] Common urea equal to the nitrogen, HQ and DCD in the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer of Example 1 was mixed with HQ and DCD as control 1;

[0101] Epoxy resin coated urea having the same amount of nitrogen, HQ and DCD as those in the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer of Example 1 was mixed with HQ and DCD as control 2.

[0102] The results of the cumulative release rate of nitrogen and inhibitors in control 1 are as follows: Figure 4 As shown in (a), although the release of urea and inhibitor is relatively synchronous after mixing, the release period of the two is less than 20 days.

[0103] The results of the cumulative release rate of nitrogen and inhibitors in control 2 are as follows: Figure 4 As shown in (b), the coated nitrogen fertilizer can maintain a longer nitrogen release period after being mixed with the inhibitor, but the inhibitor is released faster. On the 21st day, the cumulative release rate of the inhibitor has reached 99%, but the cumulative release rate of nitrogen is only 27.25%. The two are obviously out of sync.

[0104] The cumulative release rate of nitrogen and inhibitor of the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer prepared in Example 1 is as follows: Figure 4 As shown in (c), the release time of HQ and DCD was significantly extended from about 14 days to about 42 days. The synchronous release performance of inhibitors and nitrogen was also significantly improved, and the release periods of the two were basically the same.

[0105] Test Example 5:

[0106] 1. Test method:

[0107] This experiment used winter wheat variety Jimai 22 as the experimental material and was conducted in Mazhuang Town, Tai'an City, Shandong Province. A total of 6 treatments were set up, each treatment was repeated three times, and the plot area was 24m 2 The sowing rate is 18 catties / mu.

[0108] The fertilizers and nutrient contents used in this experiment are: superphosphate, purchased from a local fertilizer station, N-P2O5-K2O content of 0-12-0; potassium chloride, purchased from a local fertilizer station, N-P2O5-K2O content of 0-0-60; ordinary urea, purchased from a local fertilizer station, N-P2O5-K2O content of 46-0-0; the coated urea with a controlled release period of 60 days used in control group 2 is prepared in the same manner as in Example 1 using epoxy resin as the coating material and ordinary urea as the nitrogen fertilizer. One-time application type winter wheat synchronous nutrient fertilizer prepared in Examples 5-8.

[0109] The NPK application rates for all treatments were as follows: N: 240 kg / hm 2 , P2O5: 105kg / hm 2 , K2O: 105kg / hm 2 . Among them, superphosphate was used as phosphorus fertilizer and potassium chloride was used as potash fertilizer, which were applied once before sowing. Only different nitrogen fertilizers were used as variables, and the fertilization operations of each treatment were shown in Table 3. Control group 1 and control group 2 added HQ (urease inhibitor) and DCD (nitrification inhibitor) in an amount equal to that of Example 5 to ensure the control variables, and the method of use was to fully mix with nitrogen fertilizer and apply once as a base.

[0110] Table 3: Fertilization scheme for wheat trial

[0111]

[0112] When the wheat matures, the yield (kg / hm 2 ) Soil available nitrogen content (mg / kg), plant aboveground nitrogen content (%). Soil available nitrogen was determined by flow injection analyzer (AA3, Germany) after potassium chloride extraction, and the nitrogen content of grains and aboveground parts was determined by crushing the corresponding parts, digesting them with H2SO4-H2O2, and then using a fully automatic Kjeldahl nitrogen analyzer (K9860, China). The agronomic utilization rate of nitrogen fertilizer and nitrogen utilization efficiency were calculated using the following formula:

[0113] Agronomic utilization rate of nitrogen fertilizer (kg / kg) = (yield in the nitrogen application area - yield in the non-nitrogen application area) / nitrogen application amount

[0114] Apparent utilization rate of nitrogen fertilizer (%) = (nitrogen accumulation in the aboveground part of the nitrogen application area - nitrogen accumulation in the aboveground part of the non-nitrogen application area) / nitrogen application amount × 100%.

[0115] 2. Test results

[0116] Yield of each treatment group (kg / hm 2 ), grain nitrogen accumulation (kg / hm 2 ), agronomic efficiency of nitrogen fertilizer (kg / kg), and apparent utilization rate of nitrogen fertilizer (%) test results are shown in Table 4.

[0117] Table 4: Measurement data of different fertilization treatments

[0118]

[0119] As can be seen from Table 4, the treatments of Examples 5-8 can increase yield by 14.45%-18.81% and 8.44%-12% respectively, and the grain nitrogen accumulation is also increased by 22.83%-29.46% and 10.44-16.40% respectively compared with the conventional urea mixed inhibitor (control group 1) and the controlled-release urea mixed inhibitor (control group 2); compared with the controlled-release urea mixed inhibitor (control group 2), the agronomic efficiency of nitrogen fertilizer and the apparent utilization rate of nitrogen fertilizer are significantly improved. This shows that the synchronous slow-release type winter wheat special nitrogen fertilizer of urea and urease / nitrification inhibitor prepared by the method of the present invention can significantly improve the utilization rate of nitrogen fertilizer, increase the nitrogen absorption of wheat, and ultimately increase the yield of winter wheat compared with the conventional controlled-release fertilizer.

[0120] The soil available nitrogen content and wheat nitrogen uptake in each treatment group at different wheat growth stages are shown in Figure 2. Figure 5 As shown. Figure 5 It can be seen that the peak value of wheat nitrogen absorption is mainly in the jointing stage and flowering stage, and the demand for nutrients in the wintering stage is relatively small. The peak value of soil available nitrogen in the control group 1 treatment (common urea mixed with inhibitors) appears in the wintering stage, and then gradually decreases, which does not meet the law of wheat nutrient demand. The peak value of soil available nitrogen in the control group 2 (controlled-release fertilizer mixed with inhibitors) appears in the jointing stage, which is in line with the law of wheat fertilizer requirement in the early stage, but the soil available nitrogen content continues to decline after the jointing stage, and the demand for nitrogen in the flowering stage of wheat cannot be met. The change trend of soil available nitrogen in the treatment of Examples 5-8 is basically the same, and the peak value appears in the jointing stage and flowering stage, which is basically consistent with the law of wheat "M" type fertilizer requirement. The above results show that the urea prepared by the present invention and the urease / nitrification inhibitor synchronous slow-release winter wheat special nitrogen fertilizer can better match the nitrogen demand of winter wheat and ensure the soil nitrogen supply in the later growth period.

[0121] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer, characterized in that: Prepared by the following method: (1) mixing urea, urease inhibitor, nitrification inhibitor, plant fiber and modified biochemical fulvic acid in a weight ratio of 100:(0.1-5):(0.4-5):(3-12):(4-15) to obtain a synergistic fertilizer powder; mixing the synergistic fertilizer powder with silica fume modified polypropylene alcohol to obtain synergistic fertilizer granules; (2) The synergistic fertilizer particles are coated to prepare a urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer.

2. The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer according to claim 1, characterized in that: In step (1), the plant fiber is selected from one or more of wood fiber, bamboo fiber, flax fiber, sisal fiber and coconut fiber.

3. The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer according to claim 1, characterized in that: In step (1), the modified biochemical fulvic acid is prepared by the following method: Mix the biochemical fulvic acid, acetone and silane coupling agent in the ratio of (3-6) g: (12-36) ml: (2-9) ml, filter, dry and grind the residue.

4. The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer according to claim 3, characterized in that: The silane coupling agent is selected from one or more of γ-methacryloxypropyltrimethoxysilane, 3-(2,3-epoxypropyloxy)propyltrimethoxysilane and 3-aminopropyltriethoxysilane.

5. The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer according to claim 1, characterized in that: In step (1), the silica fume modified polypropylene alcohol is prepared by the following method: Put polyvinyl alcohol in a water bath at 85℃-95℃ until it is completely dissolved, add silica fume and inorganic acid, stir evenly, and then perform ultrasonic treatment and degassing to obtain silica fume modified polyvinyl alcohol; The ratio of the added amounts of polyvinyl alcohol, silica fume and inorganic acid is (3-7) g: (2-5) g: (12-35) ml.

6. The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer according to claim 1, characterized in that: The inorganic acid is hydrochloric acid, sulfuric acid or nitric acid with a mass fraction of 5-16%.

7. The urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer according to claim 1, characterized in that: In step (2), the amount of coating material used is 3-7% of the weight of the synergistic fertilizer particles.

8. A one-time application type winter wheat synchronous nutrition blended fertilizer, characterized in that: The invention is obtained by mixing urea, the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer of claim 1 with a controlled release period of 60 days, and the urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer of claim 1 with a controlled release period of 90 days.

9. The one-time application type winter wheat synchronous nutrition blended fertilizer according to claim 8, characterized in that: The weight ratio of urea, urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of 60 days, and urea-urease / nitrification inhibitor synchronous slow-release nitrogen fertilizer with a controlled release period of 90 days is (3-4): (1-3): (4-5).

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