Compound fertilizer as well as preparation method and application thereof

Abstract

The invention provides a compound fertilizer as well as a preparation method and application thereof. The preparation method comprises the following steps: atomizing a yeast metabolite suspension, spraying the atomized yeast metabolite suspension on the surface of a sphere core, and drying the atomized yeast metabolite suspension to obtain the compound fertilizer, wherein the sphere core comprises a nitrogen fertilizer and a potassium fertilizer. Inorganic nitrogen fertilizer and potash fertilizer are used as ball cores of fertilizer particles, the yeast metabolite suspension is atomized and sprayed on the surfaces of the nitrogen fertilizer and the potash fertilizer, organic components can be uniformly distributed on the surfaces of the inorganic ball cores, the granulation process is simple to operate, the compound fertilizer with better water solubility is obtained, the compound fertilizer is more easily absorbed and utilized by soil in the application process, and the water solubility of the compound fertilizer is improved. A certain positive influence is provided for the growth of grapes.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of fertilizer production, in particular to a compound fertilizer and a preparation method and application thereof. BACKGROUND

[0002] Grape is a kind of fruit tree that really likes potassium, and is also called potassium crop. The potassium absorption of grape is 0.3-0.65 kg per 100 kg of grape. Sufficient potassium supply can increase the sugar content of grape and promote the coloring of grape. According to the market and practice, the potassium fertilizer for grape spraying is mainly selected from potassium dihydrogen phosphate, potassium sulfate and high-quality wood ash leaching solution.

[0003] The utilization rate of inorganic fertilizer is low, and the loss caused by volatilization, loss or leaching leads to huge economic loss and serious environmental pollution. In comparison, the combination of organic and inorganic components can not only improve the utilization effect of fertilizer and promote the growth and development of crops, but also fundamentally solve the soil problem, reduce the loss, protect the soil and environment and the like. However, due to the defects of the components and granulation methods of the existing organic-inorganic compound fertilizer applied to grape growth, the obtained compound fertilizer particles are often difficult to be water-soluble, and can only be used as base fertilizer, which cannot be applied to water-soluble integration, resulting in low conversion efficiency of the fertilizer and low efficiency in promoting the growth of grape.

[0004] In the existing production technology of organic-inorganic compound fertilizer, the direct mixing, extrusion granulation or high tower granulation is mainly used for production.

[0005] CN1286777C produces various specifications of mixed compound fertilizer through simple mixing process according to the different utilization of amino acid tail liquid and various inorganic granular fertilizers by crops and soil. The product is easy to form stratification due to the difference in particle size and density of raw materials through simple mixing. CN101108779B mixes and ferments materials such as sugarcane residue, filter mud, sugarcane residue powder, wheat bran and adjusting agent to form organic fertilizer, and then mixes a certain amount of inorganic elements to form organic-inorganic compound fertilizer through dry extrusion granulation. The organic raw material used in the application cannot be water-soluble, and it is difficult to meet the requirements of flushing or drip irrigation. CN101781134B mixes molten urea solution or ammonium nitrate solution with potassium fertilizer to obtain a mixture, adds potassium fulvate or ammonium humate for mixing and chelation, and then sends the mixture into a high tower mixing tank for high tower granulation. The compound fertilizer produced by the method has a certain water-solubility, but a high-temperature mixing stage is needed before granulation, and the high temperature will cause the reaction between raw materials, which limits the applicable formula.

[0006] Therefore, how to provide a compound fertilizer with good water solubility and good formula applicability, and a preparation method thereof, has certain significance for promoting grape fruit color change and improving grape fruit sugar content during application. SUMMARY

[0007] The main purpose of the present application is to provide a compound fertilizer and a preparation method and application thereof, so as to solve the problem of poor water solubility of organic-inorganic compound fertilizer in the prior art.

[0008] In order to achieve the above-mentioned purpose, according to the first aspect of the present application, a preparation method of a compound fertilizer is provided, the preparation method comprising: atomizing a yeast metabolite suspension, spraying it on the surface of a spherical core, and drying to obtain a compound fertilizer; wherein the spherical core comprises: nitrogen fertilizer and potassium fertilizer.

[0009] Further, the dry matter content in the yeast metabolite suspension is 45-55% by mass fraction; preferably, the dry matter comprises: organic matter and inorganic salt, the organic matter comprises any one or more of: fulvic acid, humic acid or betaine, and the inorganic salt comprises any one or more of: nitrogen salt, potassium salt, magnesium salt or calcium salt; preferably, the organic matter accounts for 40-50% of the dry matter by mass fraction, and the inorganic salt accounts for 50-60% of the dry matter by mass fraction; preferably, the fulvic acid accounts for 80-100% of the organic matter by mass fraction; preferably, the total mass of the nitrogen salt and the potassium salt accounts for 30-40% of the inorganic salt by mass fraction; preferably, the mass ratio of the nitrogen salt to the potassium salt is 20-40:60-80 by mass fraction.

[0010] Further, the volume-mass ratio m of the mixture of the yeast metabolite suspension, the nitrogen fertilizer and the potassium fertilizer is 60-80:20-40; preferably, the nitrogen fertilizer is fertilizer-grade ammonium sulfate, and the potassium fertilizer is fertilizer-grade monopotassium phosphate; preferably, the mass ratio of the fertilizer-grade ammonium sulfate to the fertilizer-grade monopotassium phosphate is 1:1; preferably, the content of the total water-soluble nitrogen in the fertilizer-grade ammonium sulfate is ≥20% by mass fraction; preferably, the sum of the contents of the water-soluble phosphorus pentoxide and the water-soluble potassium oxide in the fertilizer-grade monopotassium phosphate is ≥80% by mass fraction. 3

[0011] Further, before the atomization of the yeast metabolite suspension, the preparation method comprises: filtering the yeast metabolite suspension; preferably, the screen mesh aperture of the filtering is 20-10 mesh.

[0012] Further, the feeding speed of the yeast metabolite suspension is 2.4-4.0 m 3 / h; preferably, the feeding speed of the nitrogen fertilizer and the potassium fertilizer is 1.0-1.6 t / h.

[0013] ​Further, the ambient temperature for spraying the yeast metabolite on the surface of the spherulites is 120-160°C; preferably, the drying temperature is 130-150°C.

[0014] Further, after drying, the dried product is sieved, preferably, the particle size of the sieved dried product is 1.0-3.0mm; preferably, the spherulites further comprise: yeast metabolite fine powder.

[0015] To achieve the above object, according to a second aspect of the present application, a compound fertilizer obtained by the above preparation method is provided, wherein the content of organic matter in the compound fertilizer is ≥20% by mass fraction, the total content of nitrogen, phosphorus and potassium elements in the compound fertilizer is ≥20%, and the moisture content in the compound fertilizer is ≤5%.

[0016] To achieve the above object, according to a third aspect of the present application, a method for applying the compound fertilizer obtained by the above preparation method is provided, which comprises: applying the compound fertilizer once every 7-8 days when the grape enters the fruiting stage, and the application amount of the compound fertilizer is 10-12 kg / acre each time.

[0017] To achieve the above object, according to a fourth aspect of the present application, the use of the compound fertilizer obtained by the above preparation method in promoting grape growth is provided.

[0018] By using the technical scheme of the present application, the inorganic components of nitrogen fertilizer and potassium fertilizer are used as the spherulites of the fertilizer particles, the yeast metabolite suspension is atomized and sprayed on the surface of the nitrogen fertilizer and potassium fertilizer, and the organic components can be uniformly distributed on the surface of the inorganic spherulites. The granulation process is simple, the compound fertilizer with good water solubility is obtained, the compound fertilizer is more easily absorbed by the soil during application, and a certain positive effect is provided for the growth of the grape. DETAILED DESCRIPTION

[0019] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0020] The present application will be described in further detail below with reference to specific embodiments, which cannot be understood as limiting the scope of the present application.

[0021] As mentioned in the background art, since the compound fertilizer obtained by using the existing method for preparing fertilizer has poor water solubility, the conversion efficiency is low during the process of using the compound fertilizer for grape growth, which cannot effectively exert its efficacy, and to some extent, limits the application scenarios of the compound fertilizer. Therefore, the present application proposes a method for preparing a compound particle with good water solubility, which can provide strong material support for grape growth in a simple and efficient manner.

[0022] In a first typical embodiment of the present application, a preparation method of compound fertilizer is provided, the preparation method comprising: atomizing a yeast metabolite suspension, spraying the yeast metabolite suspension on the surface of a spherical core, and drying to obtain the compound fertilizer; wherein the spherical core comprises: a nitrogen fertilizer and a potassium fertilizer.

[0023] Using inorganic components, i.e., the nitrogen fertilizer and the potassium fertilizer, as the spherical core of the fertilizer particles, and atomizing the yeast metabolite suspension to spray on the surface of the nitrogen fertilizer and the potassium fertilizer, the organic components can be uniformly distributed on the surface of the inorganic spherical core. The granulation process is simple, and the compound fertilizer with good water solubility is obtained, which is more easily absorbed by the soil during application and provides a certain positive effect on the growth of grapes.

[0024] To further obtain the compound fertilizer with better granulation effect by atomization and spraying, in a preferred embodiment, the dry matter content in the yeast metabolite suspension is 45-55% by mass fraction; preferably, the dry matter comprises: organic matter and inorganic salt, the organic matter comprises any one or more of: fulvic acid, humic acid, or betaine, and the inorganic salt comprises any one or more of: nitrogen salt, potassium salt, magnesium salt, or calcium salt; preferably, the organic matter accounts for 40-50% of the dry matter by mass fraction, and the inorganic salt accounts for 50-60% of the dry matter by mass fraction; preferably, the fulvic acid accounts for 80-100% of the organic matter by mass fraction; preferably, the total mass of the nitrogen salt and the potassium salt accounts for 30-40% of the inorganic salt by mass fraction; and preferably, the mass ratio of the nitrogen salt to the potassium salt is 20-40:60-80 by mass fraction. The yeast metabolite suspension with the above composition and ratio is atomized and sprayed, which is more likely to form the compound fertilizer with good shape and good water solubility, and the compound fertilizer is better absorbed by grapes, promoting the increase of sugar content and the color change of grapes.

[0025] To further obtain the compound fertilizer with good water solubility suitable for increasing sugar content and color change of grapes, the proportion of the organic component for spraying and the solid-loaded inorganic component needs to be further limited, in a preferred embodiment, the volume-mass ratio m 3 / t of the mixture of the yeast metabolite suspension and the nitrogen fertilizer and the potassium fertilizer is 60-80:20-40; preferably, the nitrogen fertilizer is fertilizer-grade ammonium sulfate, and the potassium fertilizer is fertilizer-grade monopotassium phosphate; preferably, the mass ratio of the fertilizer-grade ammonium sulfate to the fertilizer-grade monopotassium phosphate is 1:1; preferably, the content of the total water-soluble nitrogen in the fertilizer-grade ammonium sulfate is ≥20% by mass fraction; and preferably, the sum of the contents of the water-soluble phosphorus pentoxide and the water-soluble potassium oxide in the fertilizer-grade monopotassium phosphate is ≥80% by mass fraction.

[0026] In order to obtain a spraying mist with good atomization effect more efficiently, in a preferred embodiment, before the yeast metabolite suspension is atomized, the preparation method further comprises: filtering the yeast metabolite suspension; preferably, the filter screen aperture is 20-10 mesh. In order to further accurately control the proportion of the yeast metabolite suspension and the nitrogen fertilizer and the potassium fertilizer in the granulation, the feeding speed of the two is further limited, and in a preferred embodiment, the feeding speed of the yeast metabolite suspension is 2.4-4.0 m 3 / h; preferably, the feeding speed of the nitrogen fertilizer and the potassium fertilizer is 1.0-1.6 t / h.

[0027] In order to further efficiently obtain the compound fertilizer product, in a preferred embodiment, the ambient temperature for spraying the yeast metabolite on the surface of the spherical core is 120-160 DEG C; preferably, the drying temperature is 130-150 DEG C.

[0028] In order to obtain the compound fertilizer suitable for application, the particle size is further screened, and in a preferred embodiment, after drying, the dried product is screened, and preferably, the particle size of the screened dried product is 1.0-3.0 mm. In order to further save raw materials, the residual material in the granulation process is reused, and in a preferred embodiment, the spherical core further comprises: yeast metabolite fine powder.

[0029] In a second typical embodiment of the present application, a compound fertilizer obtained by the above preparation method is provided, wherein the organic matter in the compound fertilizer is ≥20% by mass fraction, the total content of nitrogen, phosphorus and potassium elements in the compound fertilizer is ≥20%, the moisture content in the compound fertilizer is ≤5%, and the water-insoluble matter in the compound fertilizer is ≤0.5%, which meets the national standard GB / T 18877-2020 for organic-inorganic compound fertilizer.

[0030] In a third typical embodiment of the present application, a method for applying the compound fertilizer is provided, which comprises: applying the compound fertilizer once every 7-8 days when the grape enters the fruiting stage, and the application amount of the compound fertilizer is 10-12 kg / acre each time. By applying the compound fertilizer to the growth process of the grape by the above method, the fruit color change of the grape can be promoted, and the sugar content of the fruit can be improved.

[0031] In a fourth typical embodiment of the present application, the application provides the use of the above compound fertilizer or the compound fertilizer obtained by the above preparation method in promoting grape growth.

[0032] The beneficial effects of the present application will be further illustrated by specific examples.

[0033] Example 1

[0034] The raw materials for preparing the organic-inorganic compound fertilizer in this embodiment include, in terms of volume / mass ratio (m 3 / t), 80 parts of a yeast metabolite suspension, 10 parts of a nitrogen fertilizer, and 10 parts of a potassium fertilizer. The yeast metabolite suspension has a dry matter content of 45%, a density of 1.25 g / L, organic matter accounting for 40% of the dry matter, and inorganic salts accounting for 60% of the dry matter; fulvic acid accounts for 100% of the organic matter; and nitrogen salts and potassium salts account for 30% of the inorganic salts, with a mass ratio of nitrogen salts to potassium salts being 20:80.

[0035] The nitrogen fertilizer is fertilizer-grade ammonium sulfate powder, and the total water-soluble nitrogen content of the fertilizer-grade ammonium sulfate powder is ≥20%; the potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate powder, and the total water-soluble phosphorus pentoxide (P2O5) and water-soluble potassium oxide (K2O) content of the fertilizer-grade potassium dihydrogen phosphate powder is ≥80%. The mass ratio of the fertilizer-grade ammonium sulfate to the fertilizer-grade potassium dihydrogen phosphate is 1:1.

[0036] The preparation method includes:

[0037] (1) The yeast metabolite suspension is stored in a buffer tank as a raw material;

[0038] (2) The raw material stored in the buffer tank is filtered through a filter screen with a mesh size of 20 meshes and then pumped into a spray gun pipe of a granulation bed by a slurry pump at a pumping speed of 4 m 3 / h, and is atomized into fine droplets by compressed air under the action of low-pressure air centrifugal force. At the same time, the nitrogen fertilizer and the potassium fertilizer are delivered into the granulation bed through an auxiliary material adding device at an adding speed of 0.5 t / h of fertilizer-grade ammonium sulfate powder + 0.5 t / h of fertilizer-grade potassium dihydrogen phosphate powder;

[0039] (3) Natural wind heated to 160°C is blown into the granulation bed, and the nitrogen fertilizer (ammonium sulfate), the potassium fertilizer (potassium dihydrogen phosphate), and the fine droplets (yeast metabolites) sprayed by the spray gun are mixed under the temperature action of the hot wind in the granulation bed. The fine droplets are sprayed on the returned dust and the ammonium sulfate and the potassium dihydrogen phosphate in a fluidized state. The particles gradually grow through agglomeration and coating. The water in the particles is evaporated by the hot air and the heater built in the granulation bed, and the particles continuously dry residual water during the discharging process, and finally are discharged through a bottom discharge valve;

[0040] The returned dust includes fine powder generated in the particle drying process (including ammonium sulfate and potassium dihydrogen phosphate powder that does not participate in granulation, and yeast metabolite powder), which is collected by a cyclone dust collector and a first bag dust collector under the action of a first induced draft fan and then returned to the granulation bed. The fine powder generated in the cooling process of the particles entering the cooling bed is collected by a second bag dust collector under the action of a second induced draft fan and then returned to the granulation bed.

[0041] (4) The granules discharged from the bottom discharge valve of the granulation bed are sent to the air-feeding system, and then enter the grading screen through the three-way valve after passing through the air-feeding cyclone separator. The granules are separated by the grading screen and then flow into the cooling bed. The drying temperature of the cooling bed is 20°C.

[0042] (5) After cooling, the granules are discharged from the cooling bed discharge valve into the air-feeding system and then transported to the finished product bin, thereby obtaining the compound fertilizer of the present application. According to the detection method specified in GB / T 18877-2020, the particle size of the granules is 1.0-3.0 mm, the organic matter content is 27.1% (dry basis), the total content of nitrogen, phosphorus and potassium is 28.0% (dry basis), the moisture content is 1.9%, and the water-insoluble content is 0.2%.

[0043] Example 2

[0044] In this embodiment, the raw materials for preparing the organic-inorganic compound fertilizer include, by weight, 60 parts of a yeast metabolite suspension, 20 parts of a nitrogen fertilizer and 20 parts of a potassium fertilizer. The dry matter content of the yeast metabolite suspension is 55%, the density is 1.30 g / L, the organic matter accounts for 50% of the dry matter, and the inorganic salt accounts for 50% of the dry matter. The fulvic acid accounts for 80% of the organic matter. The nitrogen salt and the potassium salt account for 40% of the inorganic salt. The mass ratio of the nitrogen salt to the potassium salt is 40:60.

[0045] The nitrogen fertilizer is fertilizer-grade ammonium sulfate powder, and the total water-soluble nitrogen content of the fertilizer-grade ammonium sulfate powder is ≥20%. The potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate powder, and the sum of the water-soluble phosphorus pentoxide (P2O5) and the water-soluble potassium oxide (K2O) contents in the fertilizer-grade potassium dihydrogen phosphate powder is ≥80%. The mass ratio of the fertilizer-grade ammonium sulfate to the fertilizer-grade potassium dihydrogen phosphate is 1:1.

[0046] The preparation method comprises the following steps:

[0047] (1) The yeast metabolite suspension is stored in a buffer tank as a raw material;

[0048] (2) The raw material stored in the buffer tank is filtered through a filter screen with a mesh size of 20 meshes and then pumped into the granulation bed spray gun pipe by a slurry pump at a pumping speed of 2.4 m 3 / h. The raw material is atomized into fine droplets by compressed air under the action of low-pressure air centrifugal force. At the same time, the nitrogen fertilizer and the potassium fertilizer are delivered into the granulation bed through an auxiliary material adding device at an adding speed of 0.8 t / h of fertilizer-grade ammonium sulfate powder + 0.8 t / h of fertilizer-grade potassium dihydrogen phosphate powder;

[0049] (3) The natural wind heated to 120°C is blown into the granulation bed, and under the temperature action of the hot air, the nitrogen fertilizer (ammonium sulfate), the potassium fertilizer (potassium dihydrogen phosphate), and the fine droplets (yeast metabolites) sprayed by the spray gun are mixed, the fine droplets are sprayed on the returned material dust and ammonium sulfate and potassium dihydrogen phosphate in a fluidized state, the particles gradually grow through agglomeration and coating, the water in the particles is heated and evaporated by the hot air and the heater in the granulation bed, and the particles continuously dry the residual water during the discharging process, and finally discharged through the bottom discharge valve;

[0050] The returned material dust includes fine powder generated in the particle drying process (including ammonium sulfate and potassium dihydrogen phosphate powder that does not participate in granulation, and yeast metabolite powder), which is collected by the cyclone dust collector and the first bag dust collector under the action of the first induced draft fan and then returned to the granulation bed. The fine powder generated in the cooling process of the particles entering the cooling bed is collected by the second bag dust collector under the action of the second induced draft fan and then returned to the granulation bed.

[0051] (4) The particles discharged from the bottom discharge valve of the granulation bed are sent to the air conveying system, then enter the grading screen through the three-way valve after passing through the air conveying cyclone separator, and then the particles are separated by the grading screen and then divided into the cooling bed. The drying temperature of the cooling bed is 20°C.

[0052] (5) After cooling, the particles enter the air conveying system from the discharge valve of the cooling bed, and then are transported to the finished product bin, and the organic-inorganic compound fertilizer of the application is obtained. According to the detection method specified in GB / T 18877-2020, the particle size is 1.0-3.0 mm, the organic matter content is 26.0% (dry basis), the total content of nitrogen, phosphorus and potassium is 35.1% (dry basis), the water content is 3.7%, and the water insoluble content is 0.3%.

[0053] Example 3

[0054] The raw materials for preparing the organic-inorganic compound fertilizer in this example include, by weight, 70 parts of yeast metabolite suspension, 15 parts of nitrogen fertilizer, and 15 parts of potassium fertilizer. The dry matter content of the yeast metabolite suspension is 50%, the density is 1.28 g / L, the organic matter accounts for 50% of the dry matter, and the inorganic salt accounts for 50% of the dry matter. The fulvic acid accounts for 90% of the organic matter. The nitrogen salt and the potassium salt account for 35% of the inorganic salt. The mass ratio of the nitrogen salt to the potassium salt is 30:70.

[0055] The nitrogen fertilizer is fertilizer-grade ammonium sulfate powder, and the total water-soluble nitrogen content of the fertilizer-grade ammonium sulfate powder is ≥20%. The potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate powder, and the sum of the water-soluble phosphorus pentoxide (P2O5) and the water-soluble potassium oxide (K2O) contents in the fertilizer-grade potassium dihydrogen phosphate powder is ≥80%. The mass ratio of the fertilizer-grade ammonium sulfate to the fertilizer-grade potassium dihydrogen phosphate is 1:1.

[0056] The preparation method includes:

[0057] (1) The yeast metabolite suspension is stored in a buffer tank as raw material;

[0058] (2) The raw material stored in the buffer tank is filtered by a filter screen with a mesh size of 20 meshes and then pumped into the spray gun pipe of the granulation bed by a slurry pump at a pumping speed of 2.8 m 3 / h. The nitrogen fertilizer (ammonium sulfate) and the potassium fertilizer (dihydrogen potassium phosphate) are delivered into the granulation bed by an auxiliary material adding device at an adding speed of 0.6 t / h of fertilizer grade ammonium sulfate powder + 0.6 t / h of fertilizer grade dihydrogen potassium phosphate powder, and the fine droplets (yeast metabolites) sprayed by the spray gun are atomized into fine droplets under the action of low-pressure air centrifugal force;

[0059] (3) Natural wind heated to 140℃ is blown into the granulation bed. Under the temperature action of the hot wind in the granulation bed, the nitrogen fertilizer (ammonium sulfate), the potassium fertilizer (dihydrogen potassium phosphate) and the fine droplets (yeast metabolites) sprayed by the spray gun are mixed. The fine droplets are sprayed on the returned dust and the ammonium sulfate and dihydrogen potassium phosphate in a fluidized state. The particles gradually grow by agglomeration and coating. The water in the particles is heated and evaporated by the hot air and the heater built in the granulation bed. The particles continuously dry the residual water during the discharging process, and finally discharged through the bottom discharge valve;

[0060] Among them, the returned dust includes fine powder generated in the particle drying process (including ammonium sulfate and dihydrogen potassium phosphate powder that do not participate in granulation, and yeast metabolite powder). Under the action of the first induced draft fan, the fine powder is collected by the cyclone dust collector and the first bag dust collector and then returned to the granulation bed. The fine powder generated in the cooling process of the particles entering the cooling bed is collected by the second bag dust collector under the action of the second induced draft fan and then returned to the granulation bed.

[0061] (4) The particles discharged from the bottom discharge valve of the granulation bed are sent to the air conveying system and then to the cyclone separator. After the particles pass through the three-way valve, they enter the grading screen. The particles are separated by the grading screen and then divided into the cooling bed. The drying temperature of the cooling bed is 20℃;

[0062] (5) After cooling, the particles are discharged from the cooling bed into the air conveying system and then transported to the finished product bin, and the compound fertilizer of the application is obtained. According to the detection method specified in GB / T 18877-2020, the particle size of the compound fertilizer is 1.0-3.0 mm, the organic matter content is 29.4% (dry basis), the total content of nitrogen, phosphorus and potassium is 32.1% (dry basis), the water content is 2.4%, and the water insoluble content is 0.2%.

[0063] Example 4

[0064] The raw materials for preparing the organic-inorganic compound fertilizer in this embodiment include, in parts by weight, 70 parts of a yeast metabolite suspension, 20 parts of a nitrogen fertilizer, and 10 parts of a potassium fertilizer. The yeast metabolite suspension has a dry matter content of 50%, a density of 1.28 g / L, 50% of the dry matter being organic matter and 50% of the dry matter being inorganic salts, 90% of the organic matter being fulvic acid, and 35% of the inorganic salts being nitrogen salts and potassium salts, the mass ratio of the nitrogen salts to the potassium salts being 30:70.

[0065] The nitrogen fertilizer is fertilizer-grade ammonium sulfate powder, the content of total water-soluble nitrogen in the fertilizer-grade ammonium sulfate powder being ≥20%; the potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate powder, the sum of the contents of water-soluble diaphosphorus (P2O5) and water-soluble potassium oxide (K2O) in the fertilizer-grade potassium dihydrogen phosphate powder being ≥80%. The mass ratio of the fertilizer-grade ammonium sulfate to the fertilizer-grade potassium dihydrogen phosphate is 2:1.

[0066] The preparation method includes:

[0067] (1) The yeast metabolite suspension is stored in a buffer tank as a raw material;

[0068] (2) The raw material stored in the buffer tank is filtered through a filter screen with a mesh size of 20 meshes and then pumped into a spray gun pipe of a granulation bed by a slurry pump at a pumping speed of 2.8 m 3 / h, and is atomized into fine droplets by compressed air under the action of low-pressure air centrifugal force, while the nitrogen fertilizer and the potassium fertilizer are delivered into the granulation bed through an auxiliary material adding device at an adding speed of 0.8 t / h of fertilizer-grade ammonium sulfate powder + 0.4 t / h of fertilizer-grade potassium dihydrogen phosphate powder;

[0069] (3) Natural wind heated to 140℃ is blown into the granulation bed, and the nitrogen fertilizer (ammonium sulfate), the potassium fertilizer (potassium dihydrogen phosphate), and the fine droplets (yeast metabolite) sprayed by the spray gun are mixed under the temperature action of the hot wind in the granulation bed, the fine droplets are sprayed on the returned dust in a fluidized state and the ammonium sulfate and the potassium dihydrogen phosphate, the particles gradually grow by agglomeration and coating, the water in the particles is evaporated by being heated by the hot air and a heater built in the granulation bed, and the particles are continuously dried to remove residual water during the discharging process, and finally discharged through a bottom discharge valve;

[0070] The returned dust includes fine powder generated in the particle drying process (including ammonium sulfate and potassium dihydrogen phosphate powder that does not participate in granulation, and yeast metabolite powder), which is collected by a cyclone dust collector and a first bag dust collector under the action of a first induced draft fan and then returned to the granulation bed; fine powder generated in the cooling process of the particles entering a cooling bed is collected by a second bag dust collector under the action of a second induced draft fan and then returned to the granulation bed.

[0071] (4) The granules discharged from the bottom discharge valve of the granulation bed are sent to the air-feeding system, and then enter the grading screen through the three-way valve after passing through the air-feeding cyclone separator. The granules are separated by the grading screen and then flow into the cooling bed. The drying temperature of the cooling bed is 20°C.

[0072] (5) After cooling, the granules are discharged from the cooling bed discharge valve into the air-feeding system and then transported to the finished product bin, thereby obtaining the compound fertilizer of the present application. According to the detection method specified in GB / T 18877-2020, the particle size of the granules is 1.0-3.0 mm, the organic matter content is 29.0% (dry basis), the total content of nitrogen, phosphorus and potassium is 27.5% (dry basis), the moisture content is 2.5%, and the water-insoluble content is 0.2%.

[0073] Example 5

[0074] The raw materials for preparing the organic-inorganic compound fertilizer in this example include, by weight, 70 parts of a yeast metabolite suspension, 15 parts of a nitrogen fertilizer and 15 parts of a potassium fertilizer. The dry matter content of the yeast metabolite suspension is 40%, the density is 1.20 g / L, the organic matter accounts for 50% of the dry matter, and the inorganic salt accounts for 50% of the dry matter. The fulvic acid accounts for 90% of the organic matter. The nitrogen salt and the potassium salt account for 35% of the inorganic salt. The mass ratio of the nitrogen salt to the potassium salt is 30:70.

[0075] The nitrogen fertilizer is fertilizer-grade ammonium sulfate powder, and the total water-soluble nitrogen content of the fertilizer-grade ammonium sulfate powder is ≥20%. The potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate powder, and the sum of the water-soluble phosphorus pentoxide (P2O5) and the water-soluble potassium oxide (K2O) contents in the fertilizer-grade potassium dihydrogen phosphate powder is ≥80%. The mass ratio of the fertilizer-grade ammonium sulfate to the fertilizer-grade potassium dihydrogen phosphate is 1:1.

[0076] The preparation method includes:

[0077] (1) The yeast metabolite suspension is stored in a buffer tank as a raw material;

[0078] (2) The raw material stored in the buffer tank is filtered through a filter screen with a mesh size of 20 meshes and then pumped into the granulation bed spray gun pipe by a slurry pump at a pumping speed of 2.8 m 3 / h. The raw material is atomized into fine droplets by compressed air under the action of low-pressure air centrifugal force. At the same time, the nitrogen fertilizer and the potassium fertilizer are delivered into the granulation bed through an auxiliary material adding device at an adding speed of 0.65 t / h of fertilizer-grade ammonium sulfate powder + 0.6 t / h of fertilizer-grade potassium dihydrogen phosphate powder;

[0079] (3) the natural wind heated to 165℃ is blown into the granulation bed, under the temperature action of the hot wind, the nitrogen fertilizer (ammonium sulfate), the potassium fertilizer (potassium dihydrogen phosphate) and the fine droplets (yeast metabolites) sprayed by the spray gun are mixed, the fine droplets are sprayed on the returned material dust and the ammonium sulfate and potassium dihydrogen phosphate in the fluidized state, the particles gradually grow by agglomeration and coating, the water in the particles is heated and evaporated by the hot air and the heater arranged in the granulation bed, and the particles continuously dry the residual water during the discharging process, and finally discharged through the bottom discharge valve;

[0080] The returned material dust includes: fine powder generated in the particle drying process (including ammonium sulfate and potassium dihydrogen phosphate powder which do not participate in granulation, and yeast metabolite powder), under the action of the first induced draft fan, the fine powder generated in the cooling process of the particles is collected by the cyclone dust collector and the first bag dust collector and then returned to the granulation bed.

[0081] (4) the particles discharged from the bottom discharge valve of the granulation bed are sent to the air conveying system, then enter the grading screen through the three-way valve after passing through the air conveying cyclone separator, and the particles are separated by the grading screen and then divided into the cooling bed, and the drying temperature of the cooling bed is 20℃;

[0082] (5) after cooling, the particles enter the air conveying system from the discharge valve of the cooling bed, and then are transported to the finished product bin, and the compound fertilizer of the application is obtained; according to the detection method specified in GB / T 18877-2020, the particle size is 1.0-3.0mm, the organic matter content is 25.1% (dry basis), the total content of nitrogen, phosphorus and potassium is 33.1% (dry basis), the water content is 3.4%, and the water insoluble content is 0.2%.

[0083] Under the condition that the dry matter content of the yeast metabolite suspension is low, the drying temperature is increased, the nitrogen energy consumption is greatly increased, and it is not recommended to use.

[0084] Example 6

[0085] The raw materials for preparing the organic-inorganic compound fertilizer in this example include, by weight: 70 parts of yeast metabolite suspension, 15 parts of nitrogen fertilizer and 15 parts of potassium fertilizer. The dry matter content of the yeast metabolite suspension is 60%, the density is 1.35g / L, the organic matter accounts for 50% of the dry matter, and the inorganic salt accounts for 50% of the dry matter; the fulvic acid accounts for 90% of the organic matter; the nitrogen salt and the potassium salt account for 35% of the inorganic salt; and the mass ratio of the nitrogen salt to the potassium salt is 30:70.

[0086] The nitrogen fertilizer is a fertilizer grade ammonium sulfate powder, and the content of total water-soluble nitrogen in the fertilizer grade ammonium sulfate powder is greater than or equal to 20%; the potassium fertilizer is a fertilizer grade potassium dihydrogen phosphate powder, and the sum of the contents of water-soluble diaphosphorus (P2O5) and water-soluble potassium oxide (K2O) in the fertilizer grade potassium dihydrogen phosphate powder is greater than or equal to 80%. The mass ratio of the fertilizer grade ammonium sulfate to the fertilizer grade potassium dihydrogen phosphate is 1:1.

[0087] The preparation method comprises the following steps:

[0088] (1) storing a yeast metabolite suspension in a buffer tank as a raw material;

[0089] (2) filtering the raw material stored in the buffer tank through a filter screen, and then pumping the filtered raw material into a spray gun pipe of a granulation bed by a slurry pump, wherein the mesh size of the filter screen is 20 meshes, and the pumping speed is 2.8 m 3 / h, and the fine droplets are atomized into fine droplets by compressed air under the action of low-pressure air centrifugal force, and the nitrogen fertilizer and the potassium fertilizer are delivered into the granulation bed through an auxiliary material adding device at an adding speed of 0.6 t / h of the fertilizer grade ammonium sulfate powder + 0.6 t / h of the fertilizer grade potassium dihydrogen phosphate powder;

[0090] (3) blowing natural wind heated to 120 DEG C into the granulation bed, and mixing the nitrogen fertilizer (ammonium sulfate), the potassium fertilizer (potassium dihydrogen phosphate) and the fine droplets (yeast metabolites) sprayed by the spray gun under the temperature action of the hot wind in the granulation bed, spraying the fine droplets on the returned dust in a fluidized state and the ammonium sulfate and the potassium dihydrogen phosphate, gradually growing the particles through agglomeration and coating, evaporating the moisture in the particles by the hot air and a heater arranged in the granulation bed, and continuously drying the residual moisture in the particles in the discharging process, and finally discharging the particles through a bottom discharge valve;

[0091] Among them, the returned dust includes fine powder (including ammonium sulfate powder and potassium dihydrogen phosphate powder which do not participate in granulation, and yeast metabolite powder) generated in the particle drying process, and the fine powder is collected by a cyclone dust collector and a first bag dust collector under the action of a first induced draft fan and then returned to the granulation bed; fine powder generated in the cooling process of the particles entering the cooling bed is collected by a second bag dust collector under the action of a second induced draft fan and then returned to the granulation bed.

[0092] (4) sending the particles discharged from the bottom discharge valve of the granulation bed to an air conveying cyclone separator by an air conveying system, and then feeding the particles into a sizing screen through a three-way valve, and then discharging the particles to the cooling bed through the sizing screen, and the drying temperature of the cooling bed is 20 DEG C;

[0093] (5) After cooling, the material is discharged from the cooling bed discharge valve into the pneumatic conveying system and transported to the finished product bin, and the granular product is obtained. According to the detection method specified in GB / T 18877-2020, the particle size is 1.0-3.0 mm, the organic matter content is 32.1% (dry basis), the total content of nitrogen, phosphorus and potassium is 29.3% (dry basis), the water content is 4.0%, and the water insoluble content is 0.4%. During the process, the yeast metabolite suspension atomization is not smooth, causing the spray gun to be blocked.

[0094] Example 7

[0095] The raw materials for preparing the organic-inorganic compound fertilizer in this example include, by weight, 70 parts of yeast metabolite suspension, 15 parts of nitrogen fertilizer and 15 parts of potassium fertilizer. The dry matter content of the yeast metabolite suspension is 50%, the density is 1.28 g / L, the organic matter accounts for 50% of the dry matter, and the inorganic salt accounts for 50% of the dry matter; the fulvic acid accounts for 90% of the organic matter; the nitrogen salt and the potassium salt account for 35% of the inorganic salt; and the mass ratio of the nitrogen salt to the potassium salt is 30:70.

[0096] The nitrogen fertilizer is fertilizer-grade ammonium sulfate powder, and the total water-soluble nitrogen content of the fertilizer-grade ammonium sulfate powder is ≥20%; the potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate powder, and the sum of the water-soluble phosphorus pentoxide (P2O5) and water-soluble potassium oxide (K2O) contents in the fertilizer-grade potassium dihydrogen phosphate powder is ≥80%. The mass ratio of the fertilizer-grade ammonium sulfate to the fertilizer-grade potassium dihydrogen phosphate is 1:1.

[0097] The preparation method includes:

[0098] (1) The yeast metabolite suspension is stored in a buffer tank as raw material;

[0099] (2) The raw material stored in the buffer tank is filtered through a filter screen with a mesh size of 20 meshes and then pumped into the spray gun pipe of the granulation bed by a slurry pump at a pumping speed of 2.8 m 3 / h, and is atomized into fine droplets by compressed air under the action of low-pressure air centrifugal force. At the same time, the nitrogen fertilizer and the potassium fertilizer are delivered into the granulation bed through an auxiliary material adding device at an adding speed of 0.6 t / h of fertilizer-grade ammonium sulfate powder + 0.6 t / h of fertilizer-grade potassium dihydrogen phosphate powder;

[0100] (3) Natural wind heated to 165°C is blown into the granulation bed, and the nitrogen fertilizer (ammonium sulfate), the potassium fertilizer (potassium dihydrogen phosphate) and the fine droplets (yeast metabolites) sprayed by the spray gun are mixed under the temperature action of the hot air in the granulation bed. The fine droplets are sprayed on the returned dust and ammonium sulfate, potassium dihydrogen phosphate in a fluidized state. The particles gradually grow through agglomeration and coating. The water in the particles is evaporated by heating with hot air and the heater built in the granulation bed, and the particles continuously dry the residual water during the discharging process. Finally, the particles are discharged through the bottom discharge valve;

[0101] The return dust includes fine powder generated in the granule drying process (including ammonium sulfate and potassium dihydrogen phosphate powder not involved in the granulation, and yeast metabolite powder), which is collected by the first induced draft fan, the cyclone dust collector and the first bag dust collector, and then returned to the granulation bed. The fine powder generated in the cooling process of the granules entering the cooling bed is collected by the second induced draft fan, the second bag dust collector and then returned to the granulation bed.

[0102] (4) The granules discharged from the bottom discharge valve of the granulation bed are sent to the air conveying system, then to the air conveying cyclone separator, and then to the grading screen through the three-way valve. The granules are separated by the grading screen and then divided into the cooling bed. The drying temperature of the cooling bed is 20℃.

[0103] (5) After cooling, the granules are discharged from the cooling bed discharge valve into the air conveying system, and then transported to the finished product bin, thereby obtaining the compound fertilizer of the present application.

[0104] In this embodiment, the compound fertilizer cannot be successfully prepared due to the over-high drying temperature, which causes the granules to puff up, and the system cannot be stably operated.

[0105] Example 8

[0106] In this embodiment, the raw materials for preparing the organic-inorganic compound fertilizer include, by weight, 70 parts of yeast metabolite suspension, 15 parts of nitrogen fertilizer and 15 parts of potassium fertilizer. The yeast metabolite suspension has a dry matter content of 50%, a density of 1.28 g / L, organic matter accounting for 50% of the dry matter, and inorganic salt accounting for 50% of the dry matter. Fulvic acid accounts for 90% of the organic matter. Nitrogen salt and potassium salt account for 35% of the inorganic salt. The mass ratio of the nitrogen salt and the potassium salt is 30:70.

[0107] The nitrogen fertilizer is fertilizer-grade ammonium sulfate powder, and the total water-soluble nitrogen content of the fertilizer-grade ammonium sulfate powder is ≥20%. The potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate powder, and the sum of the water-soluble phosphorus pentoxide (P2O5) and water-soluble potassium oxide (K2O) contents of the fertilizer-grade potassium dihydrogen phosphate powder is ≥80%. The mass ratio of the fertilizer-grade ammonium sulfate and the fertilizer-grade potassium dihydrogen phosphate is 1:1.

[0108] The preparation method includes:

[0109] (1) The yeast metabolite suspension is stored in a buffer tank as the raw material;

[0110] (2) The raw material stored in the buffer tank is filtered by a filter screen with a mesh size of 20 meshes, and then pumped into the granulation bed spray gun pipe by a slurry pump at a pumping speed of 2.8 m 3 / h. The raw material is atomized into fine droplets by compressed air under the action of low-pressure air centrifugal force through the spray gun. At the same time, the nitrogen fertilizer and the potassium fertilizer are delivered into the granulation bed through an auxiliary material adding device at an adding speed of 0.6 t / h fertilizer-grade ammonium sulfate powder + 0.6 t / h fertilizer-grade potassium dihydrogen phosphate powder.

[0111] (3) The natural wind heated to 115℃ is blown into the granulation bed, and under the temperature action of the hot air, the nitrogen fertilizer (ammonium sulfate), the potassium fertilizer (potassium dihydrogen phosphate) and the fine droplets (yeast metabolites) sprayed by the spray gun are mixed, the fine droplets are sprayed on the returned dust and the ammonium sulfate and potassium dihydrogen phosphate in the fluidized state, the particles gradually grow by agglomeration and coating, the water in the particles is heated and evaporated by the hot air and the heater in the granulation bed, and the particles continuously dry the residual water during the discharging process, and finally discharged through the bottom discharge valve;

[0112] The returned dust includes fine powder generated in the particle drying process (including ammonium sulfate and potassium dihydrogen phosphate powder which do not participate in granulation, and yeast metabolite powder), which is collected by the cyclone dust collector and the first bag dust collector under the action of the first induced draft fan and then returned to the granulation bed; the fine powder generated in the cooling process of the particles entering the cooling bed is collected by the second bag dust collector under the action of the second induced draft fan and then returned to the granulation bed.

[0113] (4) The particles discharged from the bottom discharge valve of the granulation bed are sent to the air conveying system, then enter the grading screen through the three-way valve after passing through the air conveying cyclone separator, and then the particles are separated by the grading screen and then divided into the cooling bed, and the drying temperature of the cooling bed is 20℃.

[0114] (5) After cooling, the particles enter the air conveying system from the discharge valve of the cooling bed, and then are transported to the finished product bin, and then the organic-inorganic compound fertilizer is obtained.

[0115] In this embodiment, the organic-inorganic compound fertilizer cannot be successfully prepared, and the product is caked due to the high moisture content of the particles caused by the too low drying temperature, and the system cannot be stably operated.

[0116] Comparative Example 1

[0117] In this embodiment, the raw materials for preparing the organic-inorganic compound fertilizer include 70 parts of yeast metabolite suspension, 15 parts of nitrogen fertilizer and 15 parts of potassium fertilizer by weight. The dry matter content of the yeast metabolite suspension is 50%, the density is 1.28 g / L, the organic matter accounts for 50% of the dry matter, and the inorganic salt accounts for 50% of the dry matter; the fulvic acid accounts for 90% of the organic matter; the nitrogen salt and the potassium salt account for 35% of the inorganic salt; and the mass ratio of the nitrogen salt to the potassium salt is 30:70.

[0118] The nitrogen fertilizer is fertilizer-grade ammonium sulfate particles, and the content of the total water-soluble nitrogen in the fertilizer-grade ammonium sulfate particles is ≥20%; the potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate particles, and the sum of the water-soluble phosphorus pentoxide (P2O5) and the water-soluble potassium oxide (K2O) in the fertilizer-grade potassium dihydrogen phosphate particles is ≥80%.

[0119] The preparation method comprises:

[0120] (1) Yeast metabolite suspension was stored in a buffer tank as raw material;

[0121] (2) The raw materials stored in the buffer tank are filtered through a filter screen and then pumped into the granulation bed spray gun pipe by a slurry pump. The filter screen has a mesh size of 20 mesh, and the pumping speed is 2.8 m / s². 3 / h, the spray gun atomizes the compressed air into fine droplets under the action of centrifugal force of low-pressure air;

[0122] (3) Natural air heated to 140°C is blown into the granulation bed. Under the action of the hot air temperature inside the granulation bed, the fine droplets sprayed by the spray gun are sprayed onto the return dust in a fluidized state. The particles gradually grow through agglomeration and coating. The moisture in the particles is heated and evaporated by the hot air and the heater built into the granulation bed. The particles are continuously dried during the discharge process and finally discharged through the bottom discharge valve.

[0123] The returned dust includes: fine powder generated during the particle drying process, which is collected by the first induced draft fan, the first cyclone dust collector, and the first bag filter and then returned to the granulation bed; and fine powder generated during the cooling process of the particles entering the cooling bed, which is collected by the second induced draft fan, the second bag filter and then returned to the granulation bed.

[0124] (4) The particles discharged from the bottom discharge valve of the granulation bed are sent to the air conveying cyclone separator by the air conveying system and then enter the classifying screen through the three-way valve. After being screened by the classifying screen, the particles are diverted to the cooling bed. The drying temperature of the cooling bed is 20℃.

[0125] (6) After cooling, the yeast metabolite particles are fed into the air conveying system from the cooling bed discharge valve and transported to the finished product silo.

[0126] (7) 2.8m 3 Yeast metabolite granules obtained by drying yeast metabolite suspension were mixed with 0.6t of fertilizer-grade ammonium sulfate granules and 0.6t of fertilizer-grade potassium dihydrogen phosphate granules through a blending device to obtain compound fertilizer. According to the method specified in GB / T 18877-2020, the particle size was 1.0–4.75 mm, the organic matter content was 30.1% (dry weight), the total nitrogen, phosphorus, and potassium content was 27.5% (dry weight), the moisture content was 3.5%, and the water-insoluble matter content was 0.6%. The product exhibited uneven stratification.

[0127] Application performance testing:

[0128] The compound fertilizers prepared in the above embodiments and comparative examples were subjected to application performance tests, including:

[0129] Grape (Shahai) as test crop, a total of 6 treatments were carried out, respectively, examples 1-4, control example 1 and blank experiment control, using the organic-inorganic compound fertilizer provided in the corresponding examples for fertilization (blank control with water); In the grape into fruit stage, start to use, every 7 days, 10 kg / mu of organic-inorganic compound fertilizer provided in the corresponding examples was applied, until the grape was harvested; The interval time of fertilizer irrigation was the same, and the amount of water irrigation was the same.

[0130] The field with medium fertility (soil organic matter content 19.30 g / kg, total nitrogen content 1.09 g / kg, alkaline hydrolysis nitrogen content 0.13 g / kg, total phosphorus content 0.52 g / kg, available phosphorus content 7.54 mg / kg, total potassium content 10.07 g / kg, available potassium content 0.11 g / kg, pH value 5.63) was selected as the test area of all examples and blank control of the application, the area of each unit test area was 20 m 2 , repeated 3 times. The above compound fertilizer was diluted 300 times with water and then irrigated, and the grape field management of the test field was carried out as the conventional planting method.

[0131] The soil respiration intensity, root activity, single fruit weight, single plant yield, sugar content and color change time were tested by the following method.

[0132] The determination of soil respiration intensity was carried out according to the provisions of LY / T 1220-199;

[0133] The determination of root activity was carried out according to the instructions of Solabio Plant Root Activity Test Kit (item number: BC5270);

[0134] The single fruit weight was weighed by balance after random sampling of grape fruits one by one, and the average value was taken;

[0135] The single plant yield was weighed by balance for single plant grape fruits, and the average value was taken;

[0136] The sugar content was detected by sugarimeter after random sampling of grape fruits one by one, and the average value was taken;

[0137] The color change time was calculated as the color change time of 50% of grape from green to red.

[0138] The performance test results are shown in Table 1.

[0139] Table 1 Performance test results

[0140]

[0141] From table 1, comparing example 1-4 and blank control, considering soil and crop indexes (including soil respiration intensity, root activity, single fruit weight, single plant yield, sugar content and color changing time, examples are better than the comparative examples and blank control, indicating that the organic-inorganic compound fertilizer provided by the application can not only activate microorganisms in the soil, but also improve the root activity of crops, thereby improving the nutrient utilization efficiency of crops, increasing the sugar content of grapes, accelerating the color changing of grapes, and effectively improving the quality of grapes. The comparative examples have improved the soil and crop indexes compared with the blank control, but because of the uneven distribution of different types of particles under the mixing process, the organic matter and total nutrient indexes fluctuate greatly, which affects the effect to a certain extent.

[0142] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects: the compound fertilizer prepared by the preparation method of the present application is a full water-soluble granule, which can realize the simultaneous application of organic and inorganic, water and fertilizer, further improve the fertilizer utilization rate, and has the effects of reducing cost and increasing efficiency, reducing loss, protecting soil and environment, etc. And the compound fertilizer is used as a topdressing with water during the grape fruiting period, which can effectively promote the color changing of grape fruits and significantly improve the sugar content in the fruits.

[0143] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a compound fertilizer, characterized in that, The preparation method includes: The yeast metabolite suspension was atomized, sprayed onto the surface of the bulb core, and dried to obtain the compound fertilizer. The core includes nitrogen fertilizer and potassium fertilizer.

2. The preparation method according to claim 1, characterized in that, The dry matter content in the yeast metabolite suspension is 45-55% by mass fraction; Preferably, the dry matter comprises: organic matter and inorganic salts, wherein the organic matter comprises any one or more of the following: fulvic acid, humic acid or betaine, and the inorganic salts comprise any one or more of the following: nitrogen salt, potassium salt, magnesium salt or calcium salt; Preferably, by mass fraction, the organic matter accounts for 40-50% of the dry matter, and the inorganic salts account for 50-60% of the dry matter; Preferably, the fulvic acid accounts for 80-100% of the organic matter by mass fraction; Preferably, the total mass of the nitrogen salt and the potassium salt accounts for 30-40% of the inorganic salt by mass fraction; Preferably, the mass ratio of the nitrogen salt to the potassium salt is 20-40:60-80 by mass fraction.

3. The preparation method according to claim 1, characterized in that, The volume-to-mass ratio of the yeast metabolite suspension to the mixture of the nitrogen fertilizer and the potassium fertilizer is m 3 / t is 60-80: 20-40; Preferably, the nitrogen fertilizer is fertilizer-grade ammonium sulfate, and the potassium fertilizer is fertilizer-grade potassium dihydrogen phosphate; Preferably, the mass ratio of fertilizer-grade ammonium sulfate to fertilizer-grade potassium dihydrogen phosphate is 1:1; Preferably, the water-soluble total nitrogen content of the fertilizer-grade ammonium sulfate is ≥20% by mass fraction; Preferably, the sum of the contents of water-soluble phosphorus pentoxide and water-soluble potassium oxide in the fertilizer-grade potassium dihydrogen phosphate is ≥80% by mass fraction.

4. The preparation method according to claim 1, characterized in that, Before the yeast metabolite suspension is atomized, the preparation method includes: The yeast metabolite suspension was filtered; Preferably, the sieve mesh size of the filter is 20-10 mesh.

5. The preparation method according to claim 1, characterized in that, The feed rate of the yeast metabolite suspension is 2.4–4.0 m / s. 3 / h; Preferably, the feeding rate of the nitrogen fertilizer and potassium fertilizer is 1.0 to 1.6 t / h.

6. The preparation method according to claim 1, characterized in that, The ambient temperature at which the yeast metabolites are sprayed onto the surface of the sphere is 120-160℃. Preferably, the drying temperature is 130-150°C.

7. The preparation method according to claim 1, characterized in that, The drying process includes: sieving the dried product. Preferably, the particle size of the dried product after sieving is 1.0-3.0 mm; Preferably, the sphere further includes: fine powder of yeast metabolites.

8. The compound fertilizer obtained by the preparation method according to any one of claims 1-7, characterized in that, By mass fraction, the compound fertilizer contains ≥20% organic matter, ≥20% total nitrogen, phosphorus and potassium, and ≤5% moisture.

9. A method for applying a compound fertilizer obtained by the preparation method according to any one of claims 1-7, characterized in that, The application method includes applying the compound fertilizer every 7-8 days when the grapes enter the fruiting period, with each application of the compound fertilizer being 10-12 kg / mu.

10. The application of the compound fertilizer obtained by the preparation method according to any one of claims 1-7 in promoting grape growth.

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