A water-soluble fertilizer for corn and its preparation method

Abstract

The present invention relates to a water-soluble fertilizer for corn and a preparation method thereof, characterized in that the nitrogen content in the water-soluble fertilizer for corn is greater than or equal to 20%, and a slow-release agent is contained. This application can effectively prevent the caking problem of the water-soluble fertilizer for corn and can increase the yield of corn.

Description

Technical Field

[0001] The present invention relates to a water-soluble fertilizer for corn and a preparation method thereof. Background Art

[0002] The growth period of corn is relatively long, generally 100 - 130 days. For traditional fertilization, high-concentration compound fertilizers, compound mixed fertilizers or blended fertilizers are generally used as base fertilizers. To save labor, each manufacturer has launched a one-shot special fertilizer for corn, that is, one-time fertilization without topdressing. Its design formula requires high concentration, that is, the total nutrient content is higher than 48%. The specific nitrogen, phosphorus and potassium ratios are usually 27 - 11 - 10, 29 - 16 - 10, 30 - 13 - 10 and 32 - 9 - 11, etc. Since its application in the market in 2004, it has received wide acclaim.

[0003] Gansu Province is located in the northwest of China. Most of its climate is temperate continental arid climate, lacking water all year round. At present, drip irrigation under plastic film is popularized in corn planting, and there is an urgent need for a supporting water-soluble fertilizer. However, with the above-mentioned high nitrogen ratio, a large amount of urea needs to be used in the formula. Different from high-concentration compound fertilizers, compound mixed fertilizers or blended fertilizers, water-soluble fertilizers are usually in powder or small particle form with a relatively large specific surface area, while high-concentration compound fertilizers, compound mixed fertilizers or blended fertilizers are large particles with a small specific surface area. Therefore, relatively speaking, water-soluble fertilizers using a large amount of urea are more likely to caking. As a result of caking, the specific surface area of the water-soluble fertilizer is reduced. Therefore, if it is directly put into water for dissolution, the dissolution speed is much slower than that of the non-caked product. If it is crushed and then put into water for dissolution, it will waste manpower and material resources. Therefore, it brings inconvenience to the use of customers and also affects the sales of products.

[0004] At the same time, due to the economic benefits of Gansu's climate and field crops being much lower than those of fruits, vegetables and other crops, the management mode of field crops cannot be as frequent in watering as that of fruits and vegetables. This requires a unique water-soluble fertilizer adapted to the field management mode.

[0005] In addition, high-concentration compound fertilizers, compound mixed fertilizers or blended fertilizers are not fully water-soluble. The anti-caking agent products they use are oily anti-caking agents plus inert powders, and both oily anti-caking agents and inert powders are insoluble in water. While water-soluble fertilizers require full water solubility. If they are not fully water-soluble, they are likely to block drip irrigation pipes or drip irrigation holes. Therefore, due to the water solubility problems of high-concentration compound fertilizers, compound mixed fertilizers or blended fertilizers and water-soluble fertilizers, water-soluble fertilizers cannot fully draw on high-concentration compound fertilizers, compound mixed fertilizers or blended fertilizers.

[0006] At present, there is no water-soluble fertilizer adapted to the field management mode, especially the water-soluble fertilizer adapted to the management mode in arid areas, nor has the problem of inconvenient use caused by directly applying the formula of special fertilizer for field corn to water-soluble fertilizer been solved. Summary of the Invention

[0007] The present invention provides a water-soluble fertilizer for corn and a preparation method thereof. The technical problems to be solved are as follows: 1) A water-soluble fertilizer suitable for the field management mode, especially for the management mode in arid areas; 2) It is inconvenient to directly apply the special fertilizer formula for field corn to the use of water-soluble fertilizer. 3) Improve the fertilizer utilization efficiency

[0008] To solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A water-soluble fertilizer for corn, with a nitrogen content of 20-32%, a phosphorus pentoxide content of 9-15%, a potassium oxide content of 9-15%, and containing a slow-release agent;

[0010] The slow-release agent is prepared according to the following steps

[0011] Add starch, phosphate, and urea to water, and react at a temperature of 95-120°C and a pressure of 0-2 MPa for 2-4 h. Cool to 20-50°C, add Bacillus, stir evenly, and after drying, the slow-release agent is obtained;

[0012] The mass ratio of starch, phosphate, urea, Bacillus amyloliquefaciens, and water is 30-50:3-15:0.02-0.6:0.2-10:35-67;

[0013] The Bacillus can degrade starch.

[0014] The phosphate is one or more of potassium dihydrogen phosphate, sodium dihydrogen phosphate, sodium pyrophosphate, potassium pyrophosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate; the Bacillus is one or two of Bacillus amyloliquefaciens or Bacillus subtilis.

[0015] The water is one or two of deionized water or distilled water.

[0016] The total mass fraction of phosphate and urea in the slow-release agent is not more than 6%; the mesh number of the slow-release agent is greater than or equal to 200 mesh.

[0017] The drying temperature is 40-60°C; dry until the moisture content is lower than 0.4%.

[0018] A preparation method of a water-soluble fertilizer for corn, characterized in that the slow-release agent, nitrogen fertilizer, phosphate fertilizer, and potassium fertilizer are mixed evenly to obtain the slow-release fertilizer;

[0019] The nitrogen fertilizer contains nitrogen; the phosphate fertilizer contains phosphorus pentoxide; the potassium fertilizer contains potassium oxide.

[0020] A preparation method of a water-soluble fertilizer for corn, characterized in that the slow-release agent accounts for 0.3-1.5% of the mass of the water-soluble fertilizer for corn.

[0021] The invention has the following beneficial technical effects:

[0022] 1) The water-soluble fertilizer for corn prepared in this application can adapt to the field management mode, especially the management mode in arid areas.

[0023] 2) The water-soluble fertilizer prepared in this application has the advantage of convenient use. That is, by adding a slow-release agent in this application, the effects of water retention and fertilizer retention can be achieved. Especially importantly, it can meet the requirements of drip irrigation and has the advantage of light product caking.

[0024] 3) In this application, phosphate is used to modify starch. After modification, the starch introduces phosphate ester groups with anionic properties. Therefore, compared with starch, it has better cation adsorption and hydrophilicity. In fertilizers, due to the strong mobility of nitrogen and easy loss, currently, the main purpose of slow-release fertilizers is to slow-release nitrogen fertilizer. Taking urea as an example, when it is applied to the soil, amide nitrogen is converted into ammonium nitrogen under the action of urease, that is, ammonium carbonate or ammonium bicarbonate is formed. Ammonium carbonate or ammonium bicarbonate is volatile, resulting in nitrogen loss. However, the modified starch in this application has good cation adsorption, that is, it adsorbs NH4 in the fertilizer + Thereby reducing nitrogen loss and playing a role in slow release. Therefore, it has a good slow-release effect.

[0025] 4) In this application, the total mass fraction of phosphate and urea in the water-soluble fertilizer for corn is finally limited to not more than 6%. This is to prevent the salt concentration from being too high during the drying process, causing the Bacillus amyloliquefaciens to dehydrate during the drying process, resulting in the growth of Bacillus amyloliquefaciens being inhibited or even killed, so that the nutrients fixed in the water-soluble fertilizer for corn cannot be released in time and the fertilizer nutrient utilization rate cannot be improved.

[0026] 5) In this application, since the mass fractions of phosphate and urea in the system need to be controlled, the amount of phosphate added is relatively small. Therefore, it is required that the water used in this application is deionized water or distilled water, thereby reducing the competition of calcium and magnesium ions in the water for phosphate and improving the utilization rate of the reaction between phosphate and starch.

[0027] 6) After cooling in this application, Bacillus amyloliquefaciens is added and stirred evenly, so that the modified starch pre-buries the Bacillus amyloliquefaciens, increasing the compatibility between the Bacillus amyloliquefaciens and the fertilizer. Since the salt concentration in the fertilizer is high, when the salt concentration reaches 10%, it has a good bactericidal effect. Therefore, the compatibility between the bacteria and the fertilizer is limited. However, the pre-burial of the Bacillus amyloliquefaciens by the modified starch can block the direct contact between the Bacillus amyloliquefaciens and the fertilizer, thereby improving the compatibility between the Bacillus amyloliquefaciens and the fertilizer.

[0028] 7) During the preparation of this application, the water content of the corn water-soluble fertilizer needs to be dried to less than 0.4%, so that the Bacillus is in a dormant state to ensure the stability of the corn water-soluble fertilizer. When the corn water-soluble fertilizer is applied to the soil, the phosphate-modified starch absorbs water to activate the pre-buried Bacillus, and the Bacillus degrades the modified starch and gradually releases the fertilizer nutrients fixed in the corn water-soluble fertilizer, thereby achieving a slow-release and full-release effect.

[0029] This application's sustained release and anti-caking mechanism:

[0030] a) The water-soluble fertilizer for corn prepared in the present application has high water absorption and adsorption, and thus has the effect of retaining water and fertilizer.

[0031] b) Slow-release mechanism of urea: Under normal circumstances, it takes 4 to 7 days for urea to be completely converted into ammonium nitrogen.

[0032] The higher the soil temperature, the faster the conversion; when the soil temperature is 30°C, the conversion only takes 2 to 3 days, and when the soil temperature is 10°C, it takes 7 to 10 days to completely convert into ammonium nitrogen. The water-soluble fertilizer for corn prepared in the present application mainly adsorbs urea and adsorbs the ammonium nitrogen produced by urea degradation. Due to the high aging stability of phosphate-modified starch, the ammonium nitrogen adsorbed by it is not easy to release, which will also cause a decrease in nitrogen utilization. Therefore, the present application adds Bacillus that can degrade starch, degrades the phosphate-modified starch to release its fixed fertilizer nutrients, thereby improving the utilization rate of fertilizer nutrients. Of course, this nutrient release also includes the release of phosphate.

[0033] c) The agglomeration of the water-soluble fertilizer for corn prepared in the present application is mainly due to the low moisture absorption point of urea. During the production process, it absorbs moisture, causing the surface of the urea particles to dissolve, thereby forming agglomerates. The slow-release agent added in the present application is water-absorbent, so it can prevent the water-soluble fertilizer for corn from agglomerating. It is particularly important that the present application limits the amount of the slow-release agent. This is because the slow-release agent prepared in the present application has low solubility in cold water. The amount used exceeds 1.5%. First, long-term stirring is required, which brings inconvenience to the use. Second, as the amount increases, it cannot be completely dissolved even if stirred, which may cause the problem of clogging the drip irrigation pipe or the drip irrigation eye during use, which is not conducive to the promotion and use of the product. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solution, the technical solution of the present invention is described in detail below in conjunction with preferred examples. Example 1

[0035] A water-soluble fertilizer for corn, with a nitrogen content of 29%, a phosphorus pentoxide content of 11%, a potassium oxide content of 10%, and containing a slow-release agent, where the slow-release agent accounts for approximately 1% of the mass of the water-soluble fertilizer for corn; specifically, it is 60 parts of urea, 21 parts of potassium dihydrogen phosphate, 5.5 parts of potassium sulfate, 13.4 parts of ammonium sulfate, and 1 part of the slow-release agent; the said parts are parts by weight.

[0036] The slow-release agent is prepared according to the following steps

[0037] Add starch, phosphate, and urea to water, react at a temperature of 100 °C for 3 h, cool to 40 °C, add Bacillus subtilis, stir evenly, and after drying, the slow-release agent for fertilizer is obtained;

[0038] The mass ratio of starch, phosphate, urea, Bacillus subtilis, and water is 40:5:0.3:1:53.7;

[0039] The said phosphate is a composition of potassium dihydrogen phosphate and potassium pyrophosphate in a mass ratio of 2:1; the said Bacillus subtilis is purchased from the China Center for Industrial Culture Collection with the number CICC 25064, which produces amylase and can hydrolyze starch.

[0040] The said water is deionized water.

[0041] The total mass fraction of phosphate and urea in the slow-release agent for fertilizer is detected to be 1.86%.

[0042] The said drying temperature is 50 °C; dry until the moisture content is lower than 0.4%.

[0043] A preparation method of a slow-release fertilizer containing the slow-release agent for fertilizer, add the slow-release agent for fertilizer to the fertilizer and mix evenly to obtain the slow-release fertilizer.

[0044] The said fertilizer is a composition of urea, potassium dihydrogen phosphate, potassium sulfate, and ammonium sulfate as described above. Example 2

[0045] A water-soluble fertilizer for corn, with a nitrogen content of 29%, a phosphorus pentoxide content of 11%, a potassium oxide content of 10%, and containing a slow-release agent, where the slow-release agent accounts for approximately 1% of the mass of the water-soluble fertilizer for corn; specifically, it is 60 parts of urea, 21 parts of potassium dihydrogen phosphate, 5.5 parts of potassium sulfate, 13.4 parts of ammonium sulfate, and 1 part of the slow-release agent; the said parts are parts by weight.

[0046] The slow-release agent is prepared according to the following steps

[0047] Add starch, phosphate, and urea to water, react under the condition of a temperature of 100 °C for 3 h, cool to 40 °C, add Bacillus amyloliquefaciens, stir evenly, and after drying, the slow-release agent for fertilizer is obtained;

[0048] The mass ratio of starch, phosphate, urea, Bacillus amyloliquefaciens and water is 40:5:0.3:1:53.7;

[0049] The phosphate is a composition of potassium dihydrogen phosphate and potassium pyrophosphate in a mass ratio of 2:1; the Bacillus amyloliquefaciens is purchased from the China Center for Industrial Culture Collection with the number CICC 20164, which produces amylase and can enzymatically hydrolyze starch.

[0050] The water is deionized water.

[0051] The total mass fraction of phosphate and urea in the fertilizer slow-release agent is detected to be 1.87%.

[0052] The drying temperature is 50 °C; it is dried until the moisture content is lower than 0.4%.

[0053] A preparation method of a slow-release fertilizer containing the fertilizer slow-release agent is to add the fertilizer slow-release agent to the fertilizer and mix evenly to obtain the slow-release fertilizer.

[0054] The fertilizer is a composition of urea, potassium dihydrogen phosphate, potassium sulfate and ammonium sulfate mentioned above. Example 3

[0055] A water-soluble fertilizer for corn has a nitrogen content of 30%, a phosphorus pentoxide content of 13%, a potassium oxide content of 10%, and contains a slow-release agent, and the slow-release agent accounts for about 1% of the mass of the water-soluble fertilizer for corn; specifically, it is 62 parts of urea, 25 parts of potassium dihydrogen phosphate, 3 parts of potassium sulfate, 9.9 parts of ammonium sulfate, and 1 part of the slow-release agent; the part is a weight part.

[0056] The slow-release agent is carried out according to the following steps

[0057] Add starch, phosphate and urea to water, react at a temperature of 110 °C and a pressure of 1.5 MPa for 2 h, cool to 30 °C, add Bacillus amyloliquefaciens, stir evenly, and obtain the fertilizer slow-release agent after drying;

[0058] The mass ratio of starch, phosphate, urea, Bacillus amyloliquefaciens and water is 45:8:1:2:44;

[0059] The phosphate is a composition of potassium dihydrogen phosphate and dipotassium hydrogen phosphate in a mass ratio of 1:3; the Bacillus amyloliquefaciens is purchased from the China Center for Industrial Culture Collection with the number CICC 23281.

[0060] The water is distilled water.

[0061] The total mass fraction of phosphate and urea in the fertilizer slow-release agent is detected to be 2.98%.

[0062] The drying temperature is 60°C; dry until the moisture content is less than 0.4%.

[0063] A preparation method of a slow-release fertilizer containing a slow-release agent for fertilizers. Add the slow-release agent for fertilizers to the fertilizer and granulate to obtain the slow-release compound fertilizer.

[0064] The granulation temperature is 65 ± 5°C;

[0065] The fertilizer is a composition of urea, potassium dihydrogen phosphate, potassium sulfate, and ammonium sulfate as described above. Example 4

[0066] A water-soluble fertilizer for corn, with a nitrogen content of 32%, a phosphorus pentoxide content of 9%, a potassium oxide content of 11%, and containing a slow-release agent. The slow-release agent accounts for 1.2% of the mass of the water-soluble fertilizer for corn; specifically, it is 67 parts of urea, 17 parts of potassium dihydrogen phosphate, 10 parts of potassium sulfate, 5.8 parts of ammonium sulfate, and 1.2 parts of the slow-release agent; the parts are parts by weight.

[0067] The slow-release agent is carried out according to the following steps

[0068] Add starch, phosphate, and urea to water. Under the condition of a temperature of 98°C, react for 4 hours, cool to 45°C, add Bacillus subtilis, stir evenly, and after drying, obtain the slow-release agent for fertilizers;

[0069] The mass ratio of starch, phosphate, urea, Bacillus subtilis, and water is 35:3:0.08:0.5:61.43;

[0070] The phosphate is a composition of sodium dihydrogen phosphate and sodium pyrophosphate in a mass ratio of 1:2.

[0071] The water is distilled water.

[0072] The total mass fraction of phosphate and urea in the slow-release agent for fertilizers is detected to be 1.31%.

[0073] The drying temperature is 55°C; dry until the moisture content is less than 0.4%.

[0074] A preparation method of a slow-release fertilizer containing a slow-release agent for fertilizers. Add the slow-release agent for fertilizers to the water-soluble fertilizer and mix evenly to obtain the slow-release water-soluble fertilizer.

[0075] The water-soluble fertilizer is a composition of urea, potassium dihydrogen phosphate, potassium sulfate, and ammonium sulfate as described above.

[0076] The beneficial effects of the present invention are further illustrated below in combination with experimental data:

[0077] Test materials

[0078] 1.1 Test site: Gansu Institute of Cold and Arid Eco-Agriculture.

[0079] 1.2 Experimental detection: water-insoluble matter (%), detected using crucibles P70 (50 - 70 μm) and P7 (4 - 7 μm) respectively; caking rate (%).

[0080] 1.3 Test objects: blank (except for not adding a slow-release agent, other preparations are the same as in Example 1), Comparative 1 (except that the slow-release agent added is starch, others are the same as in Example 1), the slow-release fertilizers prepared in Example 1, Example 2, Example 3, and Example 4.

[0081] 1.4 Test method: For water-insoluble matter, determine according to NY / T 1973 - 2021 Water-soluble fertilizers - Determination of water-insoluble matter content and pH; for caking rate, stack 40 high, store for one month, take the second-to-last package, drop freely from 2 meters, once for each side, and sieve using a sieve with a pore size of 2 mm. Among them, record the mass in the package as m, and the mass of particles with a particle size larger than 2 mm as m1. The caking rate = m1 / m * 100%.

[0082] 2 Results and analysis

[0083] The average values of water-insoluble matter (%) and caking rate (%) for each treatment are shown in Table 1.

[0084]

[0085] It can be seen from Table 1 that for the blank (except for not adding a slow-release agent, other preparations are the same as in Example 1), there is a serious problem of caking, which brings inconvenience to the use of the product; for Comparative 1, the water-insoluble matter does not meet the requirements of NY / T 1107 Macronutrient water-soluble fertilizers.

[0086] Test two

[0087] Test materials

[0088] 1.1 Test site: Seed production corn base in Huangyang Town, Liangzhou District, Wuwei City, corn variety Xianyu 335.

[0089] 1.2 Experimental detection: number of grains per ear (grains), weight of grains per ear (g), 100-grain weight (g), and yield (kg), randomly select 100 plants from each plot for statistics;

[0090] 1.3 Test subjects: Blank (except that the slow-release agent is not added, and other preparations are the same as in Example 1), CK (the water-soluble fertilizer used has a nutrient-balanced ratio of 17-17-17, and the slow-release agent is not added), Comparative 1 (except that Bacillus subtilis is not added, and other preparations are the same as in Example 1), Comparative 2 (except that Bacillus subtilis is purchased from the China Center for Industrial Culture Collection with the number CICC 23830, and other preparations are the same as in Example 1. This Bacillus subtilis produces laccase and can degrade lignin but not starch), Comparative 3 (except that the mass ratio of starch, phosphate, urea, Bacillus subtilis and water is 40:5:3:1:51 when preparing the slow-release agent, and the total mass fraction of phosphate and urea in the fertilizer slow-release agent is 6.79% as detected, and other preparations are the same as in Example 1), the water-soluble fertilizers prepared in Example 1, Example 2, Example 3 and Example 4.

[0091] 1.4 Test design: Divide the adjacent 9 mu of corn fields into 9 plots, each plot is 1 mu, and drip irrigation is used for treatment. The method of using the water-soluble fertilizer is to dilute the slow-release fertilizer 1200 times with water and then carry out drip irrigation.

[0092] Note: The pipeline must be cleaned with clean water before and after drip irrigation.

[0093] In this experiment, each treatment was drip-irrigated 3 times, and the fertilizer application amount for each drip irrigation was 10 kg.

[0094] In this experiment, except for the different treatments, other management methods are the same.

[0095] 2 Results and analysis

[0096] The average values of the number of grains per ear (grains), grain weight per ear (g), 100-grain weight (g) and yield per mu (kg) of each treatment are shown in Table 2

[0097]

[0098] From the data comparison of blank, Comparative 1, and Examples 1 to 4 in Table 2, it can be seen that the formula with high nitrogen content in this application has better effects than the traditional nutrient-balanced formula. That is, the formula in this application with a nitrogen content of 20-32%, a phosphorus pentoxide content of 9-15%, and a potassium oxide content of 9-15% has certain advantages.

[0099] From the data comparison between Example 1 and blank, it can be seen that adding the slow-release agent can significantly increase the number of grains per ear, grain weight per ear, 100-grain weight and yield of corn. That is, the slow-release agent has a great influence on the effects of this application.

[0100] From the data comparison between Example 1 and Comparative 2, it can be seen that different added bacteria bring different effects. Adding Bacillus subtilis that can degrade starch can improve the use effect of the fertilizer slow-release agent.

[0101] It can be seen from the data comparison between Example 1 and Comparative Example 3 that although Bacillus subtilis capable of degrading starch was added in Comparative Example 3, the total mass fraction of phosphate and urea in the fertilizer slow-release agent was 6.79% which is greater than 6%, which may cause the added Bacillus subtilis to be unsuitable for the high-salt environment during drying and storage, and its growth is inhibited or even dies. Therefore, excellent effects cannot be shown during use.

Claims

1. A water-soluble fertilizer for corn, characterized in that, The nitrogen content is 20 - 32%, the phosphorus pentoxide content is 9 - 15%, the potassium oxide content is 9 - 15%, and it contains a slow-release agent; The slow-release agent is prepared according to the following steps: Add starch, phosphate and urea into water, react at a temperature of 95 - 120 °C and a pressure of 0 - 2 MPa for 2 - 4 h, cool to 20 - 50 °C, add Bacillus, stir evenly, and obtain the slow-release agent after drying; The mass ratio of starch, phosphate, urea, Bacillus and water is 30 - 50:3 - 15:0.02 - 0.6:0.2 - 10:35 - 67; The Bacillus can degrade starch; The slow-release agent accounts for 0.3 - 1.5% of the mass of the water-soluble fertilizer for corn.

2. The water-soluble fertilizer for corn according to claim 1, wherein The phosphate is one or more of potassium dihydrogen phosphate, sodium dihydrogen phosphate, sodium pyrophosphate, potassium pyrophosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate and dipotassium hydrogen phosphate; the Bacillus is one or two of Bacillus amyloliquefaciens or Bacillus subtilis.

3. The water-soluble fertilizer for corn according to claim 2, wherein The water is one or two of deionized water or distilled water.

4. The water-soluble fertilizer for corn as described in claim 1, wherein The total mass fraction of phosphate and urea in the slow-release agent is not more than 6%; the mesh number of the slow-release agent is greater than or equal to 200 meshes.

5. The water-soluble fertilizer for corn according to claim 1, characterized in that, The drying temperature is 40 - 60 °C; dry until the moisture content is lower than 0.4%.

6. The preparation method of the water-soluble fertilizer for corn according to any one of claims 1 to 5, characterized in that, Mix the slow-release agent, nitrogen fertilizer, phosphate fertilizer and potassium fertilizer evenly to obtain the slow-release fertilizer; The nitrogen fertilizer contains nitrogen; the phosphate fertilizer contains phosphorus pentoxide; the potassium fertilizer contains potassium oxide.

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