Multi-nutrient-element proportioned blended fertilizer and preparation method thereof

Abstract

The invention relates to the technical field of fertilizer preparation, in particular to a multi-nutrient-element matching blended fertilizer and a preparation method thereof. According to the invention, surface roughening treatment is carried out on the basic fertilizer, so that the friction force among particles is increased, and the fertilizer particles are not easy to slide and separate in the mixing and storage processes. Meanwhile, the added binder microcapsules are broken in the mixing process, a biodegradable composite binder is released, fertilizer particles are firmly bonded together, and the stability of the quality of the fertilizer is guaranteed. The binder microcapsule used in the preparation process is made of a biodegradable material, cannot pollute the soil environment, can be gradually decomposed in the soil, and is beneficial to maintaining the ecological balance of the soil and guaranteeing the long-term fertility and sustainable utilization of the soil. By improving the fertilizer utilization rate, reducing fertilizer waste and improving the crop yield and quality, the comprehensive economic benefits are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer preparation, and in particular to a multi-nutrient element mixed fertilizer and a preparation method thereof. Background Art

[0002] With the development of agricultural modernization, the requirements for crop yield and quality are increasing day by day, and scientific and reasonable fertilization has become a key link in achieving this goal. Multi-nutrient element blended fertilizers (hereinafter referred to as "blended fertilizers") have been widely used in agricultural production because they can accurately adjust nutrients according to different crops and different soil conditions. However, there are still some problems that need to be solved in the current blended fertilizers and their preparation methods.

[0003] Blended fertilizers are usually mixed with a variety of basic fertilizers and additives. The physical properties of each component, such as particle size and density, vary, making it difficult to ensure uniformity during the mixing process. Traditional mixing equipment and processes, such as drum mixers, although simple in structure and low in cost, have limited mixing effects on fertilizer particles with large differences in particle size, and are prone to uneven local nutrient concentrations. During storage and transportation, fertilizer particles of different sizes and densities may also stratify due to factors such as vibration and gravity, further destroying the uniformity of the fertilizer and resulting in inconsistent crop growth after field fertilization. In addition, some existing blended fertilizers lack an effective stabilization mechanism, and during long-term storage, certain components in the fertilizer may undergo chemical reactions, resulting in nutrient loss or reduced effectiveness.

[0004] At present, many binders and additives used in the preparation of blended fertilizers may cause potential harm to the environment. For example, some traditional binders are difficult to degrade and remain in the soil for a long time, which may affect the soil structure and microbial activity. At the same time, some preparation processes are relatively complex, with high energy consumption and large equipment investment, resulting in high production costs. This not only increases farmers' fertilization costs and reduces the market competitiveness of products, but also limits the promotion and application of high-quality blended fertilizers.

[0005] In summary, the existing multi-nutrient element ratio blended fertilizer and its preparation method have many deficiencies in nutrient adaptability, mixing uniformity and stability, environmental friendliness and production cost, etc. Therefore, it is of great practical significance to develop a multi-nutrient element ratio blended fertilizer and its preparation method that can accurately meet the nutrient requirements of crops, has uniform and stable mixing, and has an environmentally friendly and economical preparation process. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-nutrient element mixed fertilizer and a preparation method thereof, which exhibits significant advantages in promoting crop growth, increasing yield and improving quality.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for preparing a multi-nutrient element mixed fertilizer, comprising the following steps: The macronutrient fertilizer, the medium-nutrient fertilizer, the trace-nutrient fertilizer, the carrier and the binder microcapsule are spirally mixed to obtain a multi-nutrient element blended fertilizer; Part or all of the components in the macro-element fertilizer are pretreated before spiral mixing, and the pretreatment is surface roughening treatment using a fluidized bed reactor.

[0008] Preferably, part or all of the components in the macroelement fertilizer are selected from one or more of urea, diammonium phosphate, potassium sulfate, monoammonium phosphate, potassium chloride, triple superphosphate or potassium dihydrogen phosphate.

[0009] Preferably, the surface roughening treatment is performed at a temperature of 60-90°C.

[0010] Preferably, the surface roughening treatment time is 10 to 15 minutes.

[0011] Preferably, the surface roughening treatment is achieved by hot air containing silicon dioxide powder.

[0012] Preferably, the carrier is selected from one or more of bentonite, kaolin, perlite, vermiculite, peat, diatomaceous earth, leaf mold or sepiolite.

[0013] Preferably, the binder microcapsules are chitosan-sodium alginate composite binder microcapsules.

[0014] Preferably, the chitosan-sodium alginate composite binder microcapsules are obtained by a preparation method comprising the following steps: Dissolve chitosan in acetic acid solution to prepare a chitosan solution with a mass fraction of 1-3%; Dissolve sodium alginate in deionized water to prepare a sodium alginate solution with a mass fraction of 2-5%; The chitosan solution and the sodium alginate solution were mixed, and 0.1-1 mol / L calcium chloride solution was added dropwise to obtain chitosan-sodium alginate composite binder microcapsules.

[0015] Preferably, the equipment used for the spiral mixing is a continuous double-screw mixer.

[0016] The present invention also provides a multi-nutrient element mixed fertilizer prepared by the preparation method.

[0017] Technical effects and advantages of the present invention: Through scientific and reasonable nutrient ratios, waste caused by improper nutrient supply is reduced. Crops can fully absorb and utilize various nutrients in fertilizers, avoiding the excess or deficiency of some nutrients caused by unreasonable nutrient ratios in traditional fertilizers, thereby improving the utilization rate of fertilizers and reducing fertilization costs. The present invention increases the friction between particles by roughening the surface of the basic fertilizer, making it difficult for fertilizer particles to slide and separate from each other during mixing and storage. At the same time, the added binder microcapsules break during the mixing process, releasing a biodegradable composite binder, which firmly bonds the fertilizer particles together, effectively preventing stratification caused by factors such as vibration and gravity during storage and transportation, and ensuring the stability of fertilizer quality.

[0018] The binder microcapsules used in the preparation process of the present invention are made of biodegradable materials and will not pollute the soil environment. These materials can gradually decompose in the soil and will not remain for a long time like traditional binders, which helps to maintain the ecological balance of the soil and ensure the long-term fertility and sustainable utilization of the soil. By improving fertilizer utilization, reducing fertilizer waste, and improving crop yield and quality, the comprehensive economic benefits are significantly improved.

[0019] The multi-nutrient element blended fertilizer and preparation method of the present invention have shown many outstanding technical effects and advantages in meeting the nutritional needs of crops, improving the quality of fertilizers, and achieving environmental friendliness and economic efficiency, and provide a scientific, efficient and sustainable fertilization solution for agricultural production. DETAILED DESCRIPTION

[0020] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0021] Example 1 Wheat-improved multi-nutrient element blended fertilizer preparation plan: 1. Raw material preparation Macronutrient fertilizers: Urea, providing the nitrogen source, accounts for 15.4% of the total fertilizer mass (70% of the nitrogen content and 22% of the total nitrogen).

[0022] Ammonium nitrate, providing a nitrogen source, accounts for 6.6% of the total fertilizer mass (30% of the nitrogen content and 22% of the total nitrogen).

[0023] Diammonium phosphate, providing a phosphorus source, accounts for 26.1% of the total fertilizer mass (P2O5 content 12%).

[0024] Potassium sulfate provides a potassium source, accounting for 25.8% of the total fertilizer mass (K2O content 15%).

[0025] Medium element fertilizer: Calcium nitrate, providing a source of calcium, accounts for 6.5% of the total fertilizer mass (CaO content 3%).

[0026] Magnesium sulfate, providing a source of magnesium, accounts for 3.1% of the total fertilizer mass (MgO content 1.5%).

[0027] Trace element fertilizer: Chelated zinc (EDTA-chelated zinc), provides zinc element, accounting for 0.16% of the total weight of the fertilizer (Zn content 0.08%).

[0028] Borax provides boron, accounting for 0.13% of the total weight of the fertilizer (B content 0.06%).

[0029] Carrier and filler: Bentonite, accounting for 19.91% of the total weight of the fertilizer, is used to improve the physical properties of the fertilizer and increase particle stability and fluidity.

[0030] Binder microcapsules: Chitosan-sodium alginate composite binder microcapsules, accounting for 0.8% of the total weight of the fertilizer.

[0031] 2. Raw material pretreatment Urea pretreatment: Place urea particles in a fluidized bed reactor, control the temperature at 85°C, and introduce hot air containing 3μm silica powder at a flow rate of 7m³ / h for 12 minutes to roughen the surface.

[0032] DAP pretreatment: In a similar manner, the temperature was controlled at 75°C and the DAP was subjected to surface roughening treatment for 12 minutes.

[0033] Potassium sulfate pretreatment: Potassium sulfate was subjected to surface roughening treatment in a fluidized bed reactor at 65°C for 12 minutes.

[0034] 3. Preparation of Binder Microcapsules Solution preparation: Dissolve chitosan in 1% acetic acid solution to prepare a chitosan solution with a mass fraction of 2%; dissolve sodium alginate in deionized water to prepare a sodium alginate solution with a mass fraction of 3%.

[0035] Preparation of microcapsules: At a stirring speed of 350 r / min, appropriate amounts of the two solutions were mixed, and a hardener solution containing 0.5 mol / L calcium chloride was added dropwise to prepare binder microcapsules with a particle size of 75 μm.

[0036] 4. Fertilizer Mixing Preparation of continuous spiral mixer: Turn on the continuous spiral mixer (Chengheng CH-CSZX series double spiral cone mixer, CH-CSZX 3000) and set the speed to 25r / min.

[0037] Feeding and mixing: The pre-treated fertilizers, carriers, fillers and binder microcapsules are continuously fed into the spiral mixer at a feeding rate of 650kg / h. The materials stay in the mixer for 17 minutes and are discharged after being fully mixed.

[0038] Example 2 Preparation of improved multi-nutrient element blended fertilizer for corn: 1. Raw material preparation Macronutrient fertilizers: Urea, providing the nitrogen source, accounts for 15% of the total fertilizer mass (60% of the nitrogen content and 25% of the total nitrogen).

[0039] Ammonium chloride, providing a nitrogen source, accounts for 10% of the total fertilizer mass (40% of the nitrogen content and 25% of the total nitrogen).

[0040] Monoammonium phosphate, providing a phosphorus source, accounts for 21.7% of the total fertilizer mass (P2O5 content 10%).

[0041] Potassium chloride, providing potassium source, accounts for 29.5% of the total fertilizer mass (K2O content 18%).

[0042] Medium element fertilizer: Calcium sulfate, providing a source of calcium, accounts for 3.8% of the total fertilizer mass (CaO content 2%).

[0043] Magnesium nitrate, providing a source of magnesium, accounts for 3.7% of the total fertilizer mass (MgO content 2%).

[0044] Trace element fertilizer: Zinc sulfate, providing zinc element, accounts for 0.1% of the total weight of the fertilizer (Zn content 0.05%).

[0045] Ammonium molybdate provides molybdenum, accounting for 0.06% of the total weight of the fertilizer (Mo content 0.03%).

[0046] Carrier and filler: Kaolin, accounting for 15.34% of the total weight of the fertilizer, improves the physical properties of the fertilizer and ensures storage and transportation stability.

[0047] Binder microcapsules: Chitosan-sodium alginate composite binder microcapsules, accounting for 1% of the total weight of the fertilizer.

[0048] 2. Raw material pretreatment Urea pretreatment: In a fluidized bed reactor at 90°C, 3 Hot air containing silicon dioxide powder with a particle size of 4 μm was introduced at a flow rate of 100 μm / h to treat the urea particles for 15 minutes.

[0049] MAP pretreatment: The temperature was controlled at 80°C and the surface of MAP was roughened for 15 minutes.

[0050] Potassium chloride pretreatment: Potassium chloride was subjected to surface roughening treatment in a fluidized bed reactor at 70°C for 15 minutes.

[0051] 3. Preparation of Binder Microcapsules Solution preparation: Dissolve chitosan in 1% acetic acid solution to prepare a chitosan solution with a mass fraction of 2.5%; dissolve sodium alginate in deionized water to prepare a sodium alginate solution with a mass fraction of 3.5%.

[0052] Preparation of microcapsules: At a stirring speed of 400 r / min, appropriate amounts of the two solutions were mixed, and a hardener solution containing 0.6 mol / L calcium chloride was added dropwise to prepare binder microcapsules with a particle size of 90 μm.

[0053] 4. Fertilizer Mixing Continuous spiral mixer preparation: Turn on the continuous spiral mixer and set the speed to 30r / min.

[0054] Feeding and mixing: The pre-treated fertilizers, carriers, fillers and binder microcapsules are continuously fed into the spiral mixer at a feeding rate of 750kg / h. The materials stay in the mixer for 20 minutes and are discharged after being fully mixed. Example 3 Preparation of improved multi-nutrient element blended fertilizer for tomatoes: 1. Raw material preparation Macronutrient fertilizers: Urea, providing nitrogen source, accounts for 10% of the total fertilizer mass (50% of nitrogen content and 20% of total nitrogen).

[0055] Calcium ammonium nitrate provides nitrogen and calcium sources, accounting for 10% of the total weight of the fertilizer (nitrogen content 30%, total nitrogen accounts for 20%; the calcium content is included in the total calcium source).

[0056] Triple superphosphate provides the phosphorus source, accounting for 32.6% of the total fertilizer mass (P2O5 content 15%).

[0057] Potassium sulfate provides potassium source, accounting for 33.9% of the total fertilizer mass (K2O content 20%).

[0058] Medium element fertilizer: Calcium nitrate, providing a source of calcium, accounts for 7.4% of the total fertilizer mass (CaO content 4%).

[0059] Magnesium sulfate, providing a source of magnesium, accounts for 3.1% of the total fertilizer mass (MgO content 1.5%).

[0060] Trace element fertilizer: Chelated iron provides iron element, accounting for 0.12% of the total weight of the fertilizer (Fe content 0.06%).

[0061] Boric acid, providing boron, accounts for 0.11% of the total weight of the fertilizer (B content 0.05%).

[0062] Carrier and filler: Perlite, accounting for 11.47% of the total weight of the fertilizer, improves the air permeability and water retention of the fertilizer.

[0063] Binder microcapsules: Chitosan-sodium alginate composite binder microcapsules, accounting for 0.8% of the total weight of the fertilizer.

[0064] 2. Raw material pretreatment Urea pretreatment: In a fluidized bed reactor at 85°C, hot air containing 3μm silica powder was introduced at a flow rate of 7m³ / h to treat the urea particles for 13 minutes.

[0065] TSP pretreatment: The temperature was controlled at 75°C and the surface of the TSP was roughened for 13 minutes.

[0066] Potassium sulfate pretreatment: Potassium sulfate was subjected to surface roughening treatment in a fluidized bed reactor at 65°C for 13 minutes.

[0067] 3. Preparation of Binder Microcapsules Solution preparation: Dissolve chitosan in 1% acetic acid solution to prepare a chitosan solution with a mass fraction of 2%; dissolve sodium alginate in deionized water to prepare a sodium alginate solution with a mass fraction of 3%.

[0068] Preparation of microcapsules: At a stirring speed of 350 r / min, appropriate amounts of the two solutions were mixed, and a hardener solution containing 0.5 mol / L calcium chloride was added dropwise to prepare binder microcapsules with a particle size of 80 μm.

[0069] 4. Fertilizer Mixing Continuous spiral mixer preparation: Turn on the continuous spiral mixer and set the speed to 25r / min.

[0070] Feeding and mixing: The pre-treated fertilizers, carriers, fillers and binder microcapsules are continuously fed into the spiral mixer at a feeding rate of 650kg / h. The materials stay in the mixer for 18 minutes and are discharged after being fully mixed.

[0071] Example 4 Improved multi-nutrient element blended fertilizer preparation scheme for grapes: 1. Raw material preparation Macronutrient fertilizers: Urea, providing the nitrogen source, accounts for 7.2% of the total fertilizer mass (40% of the nitrogen content and 18% of the total nitrogen).

[0072] Ammonium sulfate, providing a nitrogen source, accounts for 7.2% of the total fertilizer mass (40% of the nitrogen content and 18% of the total nitrogen).

[0073] Potassium dihydrogen phosphate provides phosphorus and potassium sources, accounting for 23.1% of the total mass of the fertilizer (P2O5 content is 12%, and the K2O part is included in the total potassium source).

[0074] Potassium nitrate provides potassium and nitrogen sources, accounting for 33.7% of the total weight of the fertilizer (K2O content is 22%, and the nitrogen content is partially included in the total nitrogen source).

[0075] Medium element fertilizer: Calcium nitrate, providing a source of calcium, accounts for 5.9% of the total fertilizer mass (CaO content 3%).

[0076] Magnesium sulfate, providing a source of magnesium, accounts for 3.9% of the total fertilizer mass (MgO content 2%).

[0077] Trace element fertilizer: Manganese sulfate provides manganese element, accounting for 0.13% of the total weight of the fertilizer (Mn content 0.07%).

[0078] Copper sulfate provides copper element, accounting for 0.08% of the total weight of the fertilizer (Cu content 0.04%).

[0079] Carrier and filler: Vermiculite, accounting for 16.69% of the total weight of the fertilizer, increases the fertilizer's ability to retain water and fertilizer.

[0080] Binder microcapsules: Chitosan-sodium alginate composite binder microcapsules, accounting for 0.9% of the total weight of the fertilizer.

[0081] 2. Raw material pretreatment Urea pretreatment: In a fluidized bed reactor at 87°C, hot air containing 4μm silica powder was introduced at a flow rate of 9m³ / h to treat the urea particles for 15 minutes.

[0082] Potassium dihydrogen phosphate pretreatment: The temperature is controlled at 77°C, and the surface of potassium dihydrogen phosphate is roughened for 15 minutes.

[0083] Potassium nitrate pretreatment: Potassium nitrate was subjected to surface roughening treatment in a fluidized bed reactor at 67°C for 15 minutes.

[0084] 3. Preparation of Binder Microcapsules Solution preparation: Chitosan was dissolved in 1% acetic acid solution to prepare a chitosan solution with a mass fraction of 2.2%; sodium alginate was dissolved in deionized water to prepare a sodium alginate solution with a mass fraction of 3.2%.

[0085] Preparation of microcapsules: At a stirring speed of 370 r / min, appropriate amounts of the two solutions were mixed, and a hardener solution containing 0.55 mol / L calcium chloride was added dropwise to prepare binder microcapsules with a particle size of 95 μm.

[0086] 4. Fertilizer Mixing Continuous spiral mixer preparation: Turn on the continuous spiral mixer and set the speed to 27r / min.

[0087] Feeding and mixing: The pre-treated fertilizers, carriers, fillers and binder microcapsules are continuously fed into the spiral mixer at a feeding rate of 700 kg / h. The materials stay in the mixer for 18 minutes and are discharged after being fully mixed.

[0088] Experimental Example 1 Wheat Planting Experiment Wheat variety: Choose Jimai 22, which is widely planted locally and has good stability.

[0089] fertilizer: Fertilizer in the experimental group: The improved multi-nutrient element blended fertilizer for wheat as described above was prepared by an improved preparation method, including raw material pretreatment, addition of binder microcapsules, and dynamic continuous mixing.

[0090] Fertilizer in the control group: Fertilizer obtained by mixing with a conventional drum mixer using a common binder (polyvinyl alcohol) has the same nutrient element ratio as that of the experimental group, but the improved preparation process is not used.

[0091] Experimental design Experimental site: Select farmland with uniform soil fertility and good irrigation conditions and divide it into several areas of 30m 2 For each plot (5m×6m), a 1m wide isolation zone is set between the plots to prevent the fertilizers from affecting each other.

[0092] Group settings: Experimental group: 3 replicate plots were set up, and each plot was fertilized with an improved multi-nutrient element mixed fertilizer, with a base fertilizer and topdressing ratio of 7:3. Base fertilizer was applied before sowing combined with land preparation, and topdressing was applied during the jointing stage of wheat. (Base fertilizer dosage: about 60kg / mu; topdressing dosage: about 25kg / mu) Control group: One plot was set up and fertilizer mixed with a conventional drum mixer using a common binder was applied. The fertilization method was the same as that of the experimental group.

[0093] Sowing: During the appropriate sowing period, sow according to the local conventional planting density and the sowing depth is 3 - 4cm.

[0094] Field management: During the entire growing period, field management measures such as irrigation, pest and disease control in each plot remain consistent and are carried out in accordance with local high-yield wheat cultivation technical regulations.

[0095] Experimental measurement items and methods Growth indicators: During the jointing, heading and filling stages of wheat, 10 wheat plants were randomly selected from each plot to measure indicators such as plant height, number of leaves and leaf area.

[0096] Yield indicators: During the wheat maturity period, each plot is harvested separately, the number of ears, number of grains per ear, and thousand-grain weight are measured, and the yield is calculated.

[0097] Quality indicators: After harvest, wheat samples are sent to the laboratory to measure quality indicators such as protein content and wet gluten content.

[0098] The results are shown in Table 1: Table 1 Wheat planting results As shown in Table 1, the improved multi-nutrient element blended fertilizer of the present invention shows significant advantages in all stages of wheat growth and in terms of yield and quality indicators. In terms of growth indicators, the plant height, number of leaves, leaf area at the jointing stage, heading stage and filling stage, and the chlorophyll content of the flag leaf at the filling stage, the experimental group was compared with the control group. After statistical analysis, the P value was less than 0.05, showing significant differences. This shows that the use of improved fertilizers can more effectively promote the growth of wheat plants at various growth stages and enhance the photosynthesis capacity of leaves. The number of days of the leaf functional period during the filling stage was extended, and the experimental group averaged 4.3 days, further indicating that the improved fertilizer helps to maintain the physiological function of the leaves for a longer period of time and provide sufficient photosynthetic products for the later grain filling. In terms of yield indicators, the number of ears, number of grains per ear, thousand-grain weight and final yield, the experimental group was significantly higher than the control group (P < 0.05), reflecting the positive effect of the improved fertilizer on the components of wheat yield, thereby significantly increasing the yield. In terms of quality indicators, protein content and wet gluten content in the experimental group were also significantly higher than those in the control group (P < 0.05), indicating that the improved fertilizer has a positive effect on improving wheat quality.

[0099] Experimental Example 2 Corn Planting Experiment Corn variety: Zhengdan 958 was selected, which has strong adaptability and is widely planted locally.

[0100] Fertilizer: Experimental group fertilizer: The improved multi-nutrient element blended fertilizer for corn in Example 2 was prepared using an improved preparation method.

[0101] Fertilizer in the control group: Fertilizer obtained by mixing with a conventional drum mixer using a common binder (polyvinyl alcohol) has the same nutrient element ratio as that of the experimental group, but the improved preparation process is not used.

[0102] Experimental site: A plot with flat terrain and uniform soil fertility was selected and divided into several plots of 40 m² (5 m × 8 m) in area, with a 1.2 m wide isolation zone set between the plots.

[0103] Group settings: Experimental group: 3 replicate plots were set up, and the fertilization plan was that the base fertilizer accounted for 60% of the total fertilizer amount and was applied before sowing; the topdressing accounted for 40% during the flaring period. (Base fertilizer amount: 50kg / mu, topdressing amount: 32kg / mu.) Control group: One plot was set up and fertilizer mixed with a conventional drum mixer using a common binder was applied. The fertilization period and proportion were the same as those of the experimental group.

[0104] Sowing: In the appropriate sowing season, sow according to the locally recommended planting density, with a sowing depth of about 5cm.

[0105] Field management: Each plot maintains consistency in field management measures such as irrigation, pest and disease control, and tillage and weeding, and follows local high-yield corn cultivation management methods.

[0106] Experimental measurement items and methods Growth indicators: During the seedling, jointing, flaring and filling stages of corn, 10 corn plants were randomly selected from each plot to measure indicators such as plant height, stem diameter and number of leaves.

[0107] Yield indicators: After the corn matures, each plot is harvested separately, the number of ear rows, the number of kernels per row, the 100-kernel weight are measured, and the yield is calculated.

[0108] Economic benefits: Record inputs such as fertilizer costs and planting management costs, and calculate economic benefits based on output and market prices.

[0109] The results are shown in Table 2: Table 2 Corn planting results From Table 2, we can see that As can be seen from Table 2, the improved multi-nutrient element ratio blended fertilizer of the present invention has a significant effect on the growth, development, yield and economic benefits of corn. In terms of growth indicators, from the seedling stage to the filling stage, the plant height, stem thickness, number of leaves, number of visible leaves, number of green leaves and other indicators, the P value of the experimental group compared with the control group was less than 0.05, and the difference was significant. It shows that the improved fertilizer can better promote the nutritional growth of corn at all growth stages and make the plants stronger. The functional period of leaves in the filling stage was extended for an average of about 5.3 days in the experimental group, which means that the leaves can photosynthesize efficiently for a longer time and provide more nutrients for the development of corn grains. The yield-related indicators, the number of ear rows, the number of grains per row, the weight of 100 grains and the yield, were significantly higher in the experimental group than in the control group (P < 0.05), showing that the improved fertilizer greatly increased the yield of corn by optimizing the yield components. In terms of economic benefits, the average increase in net income of the experimental group was 235 yuan / mu, indicating that although the improved fertilizer may slightly increase the fertilizer cost, the profit growth brought by the increase in yield is more significant, and it has good economic benefits.

[0110] In summary, whether it is wheat or corn planting experiments, the use of the improved multi-nutrient element ratio blended fertilizer provided by the present invention shows significant advantages in promoting crop growth, increasing yield and improving quality.

[0111] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a multi-nutrient element mixed fertilizer, characterized in that: The following steps are involved: The macronutrient fertilizer, the medium-nutrient fertilizer, the trace-nutrient fertilizer, the carrier and the binder microcapsule are spirally mixed to obtain a multi-nutrient element blended fertilizer; Part or all of the components in the macro-element fertilizer are pretreated before spiral mixing, and the pretreatment is surface roughening treatment using a fluidized bed reactor.

2. The preparation method according to claim 1, characterized in that: Part or all of the components in the macronutrient fertilizer are selected from one or more of urea, diammonium phosphate, potassium sulfate, monoammonium phosphate, potassium chloride, triple superphosphate or potassium dihydrogen phosphate.

3. The preparation method according to claim 1, characterized in that: The temperature of the surface roughening treatment is 60-90°C.

4. The preparation method according to claim 3, characterized in that: The surface roughening treatment time is 10 to 15 minutes.

5. The preparation method according to claim 3, characterized in that: The surface roughening treatment is achieved by hot air containing silicon dioxide powder.

6. The preparation method according to claim 1, characterized in that: The carrier is selected from one or more of bentonite, kaolin, perlite, vermiculite, peat, diatomaceous earth, leaf mold or sepiolite.

7. The preparation method according to claim 1, characterized in that: The binder microcapsule is a chitosan-sodium alginate composite binder microcapsule.

8. The preparation method according to claim 7, characterized in that: The chitosan-sodium alginate composite binder microcapsule is obtained by a preparation method comprising the following steps: Dissolve chitosan in acetic acid solution to prepare a chitosan solution with a mass fraction of 1-3%; Dissolve sodium alginate in deionized water to prepare a sodium alginate solution with a mass fraction of 2-5%; The chitosan solution and the sodium alginate solution were mixed, and 0.1-1 mol / L calcium chloride solution was added dropwise to obtain chitosan-sodium alginate composite binder microcapsules.

9. The preparation method according to any one of claims 1 to 8, characterized in that The equipment used for the spiral mixing is a continuous double-screw mixer.

10. A multi-nutrient element blended fertilizer prepared by the preparation method according to any one of claims 1 to 9.

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