Synergistic urea as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of agriculture, and provides synergistic urea as well as a preparation method and application thereof. The synergistic urea provided by the invention comprises the following components in percentage by weight: 98.8 to 99.7 percent of urea and 0.3 to 1.2 percent of synergist (comprising polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide). When the synergistic urea is applied to soil, compared with urea, the synergist permeates into the soil preferentially, and polyaspartic acid can adsorb the urea and ammonium nitrogen and nitrate nitrogen converted from the urea, so that the nitrogen fixation effect is achieved, and the loss of nitrogen is reduced. Meanwhile, the polyaspartic acid, the zinc iminodisuccinate and the mannan oligosaccharide act together, so that the growth of crop roots can be promoted, the demand of the crop roots on nitrogen is improved, and the absorption of the crops on nitrogen in the soil is improved. Besides, the polyaspartic acid, the zinc iminodisuccinate and the mannan oligosaccharide act together, so that the activity of enzymes in crops can be improved, the crops can efficiently utilize low-concentration nitrogen, and the effective utilization rate of nitrogen is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of agriculture, and particularly relates to a synergistic urea and its preparation method and application. Background Art

[0002] As an important part of agricultural production, urea can supplement the urgently needed nitrogen nutrition during the critical period of crop growth. It is applied both as a component of basal compound fertilizers and as topdressing during the mid - growth stage of crops, and even in integrated water and fertilizer management. However, the main problem faced by urea is its low nitrogen utilization rate, mainly because the nitrogen demand of crop growth does not match the release rate of urea affected by soil microorganisms, enzymes, and chemical substances in the environment.

[0003] Recalling the application process of urea, specifically as follows: After nitrogen is artificially applied, a part will be absorbed and utilized by crops to promote crop growth, thereby carrying out the cycle of mineral nutrients; a part will be fixed, and this part of nitrogen changes from the mobile state to the immobile state and becomes a component of the soil; and a part will be lost, and this part of nitrogen will be lost into the air or water bodies for material cycling. Among them, only the fertilizer absorbed by crops is considered to be effectively utilized; currently, due to the existence of various forms of nitrogen, its effective utilization rate is low. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a synergistic urea and its preparation method and application. The synergistic urea provided by the present invention has a high effective utilization rate of urea.

[0005] To achieve the above - mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a synergistic urea, comprising the following components in mass percentage:

[0007] Urea 98.8 - 99.7%, synergist 0.3 - 1.2%;

[0008] The synergist includes polyaspartic acid, zinc iminodisuccinate, and mannan oligosaccharide.

[0009] Preferably, the mass ratio of polyaspartic acid, zinc iminodisuccinate, and mannan oligosaccharide is 2.5 - 5:1:0.6 - 1.2.

[0010] Preferably, the number - average molecular weight of polyaspartic acid is 10 - 15 kD.

[0011] Preferably, the synergist is used in the form of a synergist solution, and in the synergist solution, the mass fraction of polyaspartic acid is 15 - 25%.

[0012] Preferably, the preparation method of the synergist solution comprises the following steps:

[0013] Activate polyaspartic acid to obtain activated polyaspartic acid;

[0014] Mix the activated polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide, and perform adsorption to obtain the synergist solution.

[0015] Preferably, the activating reagent includes hydrogen peroxide and ferrous salt; the mass fraction of the hydrogen peroxide is 30%;

[0016] The ferrous salt includes one or more of ferrous chloride, ferrous sulfate, ferrous glycinate and ferrous citrate;

[0017] The mass ratio of the polyaspartic acid, hydrogen peroxide and ferrous salt is 150-500:15:0.015.

[0018] Preferably, the activation temperature is 40-60°C and the time is 10-20 min.

[0019] Preferably, the zinc iminodisuccinate is used in the form of a zinc iminodisuccinate solution, and in the zinc iminodisuccinate solution, the mass fraction of the zinc iminodisuccinate is 30-50%;

[0020] The mannan oligosaccharide is used in the form of a mannan oligosaccharide solution, and the mass fraction of the mannan oligosaccharide solution is 30-50%;

[0021] The adsorption is carried out under stirring, the stirring speed is 100-150 r / min, and the time is 15-30 min.

[0022] The present invention also provides a preparation method of the synergistic urea described in the above technical solution, comprising the following steps:

[0023] Mix urea and the synergist solution, and perform coating to obtain the synergistic urea.

[0024] The present invention also provides the application of the synergistic urea described in the above technical solution or the synergistic urea prepared by the preparation method described in the above technical solution in the field of fertilizers.

[0025] The present invention provides a synergistic urea.

[0026] The inventors found that the nitrogen absorbed by crops is mainly nitrate nitrogen, partly ammonium nitrogen and organic nitrogen, and only in very few cases will it directly absorb the amide nitrogen (urea nitrogen) of urea. After urea is applied to the soil, it will begin to transform into ammonium nitrogen under the action of soil urease, and ammonium nitrogen will continue to turn into nitrate nitrogen or even nitrite nitrogen under the action of nitrifying enzymes. If the transformation continues, it will turn into nitrous oxide or nitrogen oxide and be released into the air; and the loss rates of these several kinds of nitrogen are opposite, the loss rate of nitrate nitrogen is faster than that of ammonium nitrogen, and ammonium nitrogen is faster than amide nitrogen; based on the above theory, the ways to improve nitrogen absorption or transformation are relatively obvious: one is to promote the demand of crops for nitrogen, and then improve its nutrient utilization rate; the other is to balance the rate of urea turning into ammonium nitrogen and then turning into nitrate nitrogen and being lost. The synergistic urea provided by the present invention includes urea and a synergist, and the synergist includes polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide; when the synergistic urea is applied to the soil, since the solubility of the synergist is higher than that of urea, the synergist preferentially penetrates into the soil than urea; polyaspartic acid in the synergist enters the soil colloid in advance through the gaps. When urea dissolves in the soil, polyaspartic acid can adsorb urea, as well as the ammonium nitrogen and nitrate nitrogen converted from urea, playing a role in nitrogen fixation, reducing the loss of nitrogen, and thus being conducive to improving the effective utilization rate of nitrogen. At the same time, the combined action of polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide can promote the growth of crop roots, increase the demand of crop roots for nitrogen, and then improve the absorption of nitrogen in the soil by crops, and finally improve the effective utilization of nitrogen. In addition, the combined action of polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide can increase the activity of enzymes in crops, enabling crops to efficiently utilize low-concentration nitrogen, that is, when the nitrogen content in the soil is low, crops can also efficiently utilize nitrogen, improving the effective utilization rate of nitrogen.

[0027] Furthermore, the present invention defines the preparation method of the synergist. The present invention activates polyaspartic acid to enable polyaspartic acid to have ionization adsorption ability; then zinc iminodisuccinate and mannan oligosaccharide are adsorbed on the surface of polyaspartic acid. The adsorption of zinc iminodisuccinate and mannan oligosaccharide on the surface of polyaspartic acid can protect polyaspartic acid and prevent it from reacting with urea in advance, so that polyaspartic acid is added to the soil in the form of polyaspartic acid, giving full play to its role.

[0028] Furthermore, the activation reagents include hydrogen peroxide and ferrous salt. Using hydrogen peroxide and ferrous salt as the activation reagents can quickly and efficiently enable polyaspartic acid to have ionization adsorption ability. Description of the Drawings

[0029] Figure 1 It is the preparation flow chart of the synergistic urea. Detailed Embodiments

[0030] The present invention provides a synergistic urea, which comprises components in the following mass percentages:

[0031] Urea 98.8 - 99.7%, synergist 0.3 - 1.2%;

[0032] The synergist includes polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide.

[0033] Unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0034] The synergistic urea provided by the present invention includes urea with a mass percentage of 98.8 - 99.7%. In the present invention, the urea is the main component of the synergistic urea and is the nitrogen source.

[0035] The synergistic urea provided by the present invention includes a synergist with a mass percentage of 0.3 - 1.2%, specifically preferably 0.3%, 0.33%, 0.34%, 0.4%, 0.41%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1% or 1.2%. In the present invention, the synergist includes polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide. In the present invention, the mass ratio of polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide is preferably 2.5 - 5:1:0.6 - 1.2, specifically preferably 2.86:1:0.6, 3:1:0.6, 4:1:0.6 or 4.4:1:1.2.

[0036] In the present invention, the zinc iminodisuccinate is preferably obtained by chelating zinc with a chelating agent, and the chelating agent is preferably sodium iminodisuccinate or ammonium iminodisuccinate.

[0037] In the present invention, the mannan oligosaccharide is preferably obtained by decomposing straw with biological bacteria.

[0038] In the present invention, the number average molecular weight of the polyaspartic acid is preferably 10 - 15 kD, specifically preferably 10 kD, 11 kD, 12 kD, 13 kD, 14 kD or 15 kD.

[0039] In the present invention, through biological chain scission and adsorption, macromolecular polyaspartic acid can fix and activate nutrients and stimulate the ability of crops to absorb low-concentration nitrogen, thereby prolonging the utilization time of nitrogen nutrients by crops. At the same time, it can activate the nutrients fixed by the soil, keep the nutrients, especially medium and trace element nutrients, in a certain form and stimulate the absorption function. However, its too large molecular weight will limit the quick-acting property, so other substances are needed to make up for it; zinc iminodisuccinate can provide the active nutrient zinc and the degradable chelate iminodisuccinate root, and can be absorbed and utilized by crops in the form of a composite mosaic, determining the dominant growth of the radicle in the competition between the radicle and the plumule during crop germination, and preparing for the absorption of the nutrients activated by macromolecular polyaspartic acid; mannan oligosaccharide can realize the dual activation functions of enhancing nutrient absorption through cell walls, enhancing resistance to some diseases, and stimulating the biological roots and physiological enzyme activities, thereby quickly opening the absorption channels of crops for the above-mentioned nutrients.

[0040] In the present invention, the synergist is preferably used in the form of a synergist solution, and the mass fraction of polyaspartic acid in the synergist solution is preferably 15-25%, specifically preferably 15%, 20%, 21.71%, 24.60%, 24.78% or 25%.

[0041] In the present invention, the preparation method of the synergist solution preferably includes the following steps:

[0042] Activate polyaspartic acid to obtain activated polyaspartic acid;

[0043] Mix the activated polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide, and perform adsorption to obtain the synergist solution.

[0044] In the present invention, polyaspartic acid is activated to obtain activated polyaspartic acid.

[0045] In the present invention, the use form of polyaspartic acid is preferably polyaspartic acid solution or polyaspartic acid powder.

[0046] In the polyaspartic acid solution of the present invention, the mass fraction of the active ingredient polyaspartic acid is preferably 30-50%, specifically preferably 30%, 30.5%, 35%, 38%, 40%, 45% or 50%; the mass fraction of polyphosphate is 0.50-7.50%, specifically preferably 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7% or 7.5%.

[0047] In the present invention, in the polyaspartic acid powder, the mass fraction of the active ingredient polyaspartic acid is preferably 70-90%, specifically preferably 70%, 75%, 80%, 85% or 90%; the mass fraction of polyphosphate is preferably 1-15%, specifically preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%.

[0048] In the present invention, the activation reagent preferably includes hydrogen peroxide and ferrous salt. In the present invention, the mass fraction of the hydrogen peroxide is preferably 30%.

[0049] In the present invention, the ferrous salt preferably includes one or more of ferrous chloride, ferrous sulfate, ferrous glycinate and ferrous citrate.

[0050] In the present invention, based on the mass of the active ingredient polyaspartic acid, the mass ratio of polyaspartic acid, hydrogen peroxide and ferrous salt is preferably 150-500:15:0.015.

[0051] In the present invention, when the use form of the polyaspartic acid is preferably polyaspartic acid powder, water is preferably added additionally during the activation process, and the mass ratio of the polyaspartic acid powder to water is preferably 1:1-1.5, specifically preferably 1:1, 1:1.1, 1:1.2, 1:1.24, 1:1.3, 1:1.4 or 1:1.5.

[0052] In the present invention, the activation temperature is preferably 40-60°C, specifically preferably 40°C, 50°C or 60°C; the time is preferably 10-20 min, specifically preferably 10 min, 15 min or 20 min; the activation is preferably carried out under stirring conditions.

[0053] After the activation, in the present invention, the obtained liquid material is preferably cooled to room temperature to obtain the activated polyaspartic acid.

[0054] After obtaining the activated polyaspartic acid, in the present invention, the activated polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide are mixed and adsorbed to obtain the synergist solution.

[0055] In the present invention, the zinc iminodisuccinate is preferably used in the form of a zinc iminodisuccinate solution, and in the zinc iminodisuccinate solution, the mass fraction of zinc iminodisuccinate is preferably 30-50%, specifically preferably 30%, 35%, 40%, 45% or 50%. In the present invention, the mannan oligosaccharide is preferably used in the form of a mannan oligosaccharide solution, and the mass fraction of the mannan oligosaccharide solution is preferably 30-50%, specifically preferably 30%, 35%, 40%, 45% or 50%.

[0056] In a specific embodiment of the present invention, the mass ratio of the polyaspartic acid solution, zinc iminodisuccinate solution and mannan oligosaccharide solution is preferably 4-7:1-2.5:0.5-1.5, specifically preferably 4.27:1.08:0.65 or 6.52:2.17:1.31.

[0057] In a specific embodiment of the present invention, the mass ratio of the polyaspartic acid powder, zinc iminodisuccinate solution and mannan oligosaccharide solution is preferably 2-3:1-1.5:1-1.5, specifically preferably 2.46:1.11:1.33.

[0058] In a specific embodiment of the present invention, the mixing of the activated polyaspartic acid, zinc iminodisuccinate and mannan oligosaccharide specifically preferably includes the following steps: adding the zinc iminodisuccinate solution and the mannan oligosaccharide solution into the activated polyaspartic acid simultaneously; the adding speed of the zinc iminodisuccinate solution and the mannan oligosaccharide solution is preferably 1.5 L / h; stirring is preferably carried out when the zinc iminodisuccinate solution and the mannan oligosaccharide solution are added, and the rotation speed of the stirring is preferably 100-150 r / min, specifically preferably 100 r / min, 110 r / min, 120 r / min, 130 r / min, 140 r / min or 150 r / min.

[0059] In the present invention, the adsorption is preferably carried out under stirring conditions, the rotation speed of the stirring is preferably 100-150 r / min, specifically preferably 100 r / min, 110 r / min, 120 r / min, 130 r / min, 140 r / min or 150 r / min; the time is preferably 15-30 min, specifically preferably 15 min, 20 min, 25 min or 30 min, and the adsorption time is preferably counted from the time when the zinc iminodisuccinate solution and the mannan oligosaccharide solution are added completely. In the present invention, the adsorption temperature is preferably room temperature.

[0060] In the present invention, ferrous salts can provide divalent iron ions, which can promote the release of reactive oxygen species from hydrogen peroxide. The reactive oxygen species can endow polyaspartic acid with ionization adsorption ability. The ionization adsorption ability of polyaspartic acid enables it to adsorb zinc iminodisuccinate and mannan oligosaccharide, forming a synergist with a metastable structure. After the above-mentioned synergist is mixed with urea, a charge neutralization-curing reaction occurs under the action of free ammonia and free charges in urea, causing the three substances in the synergist to change from the metastable state to the stable state, so that it will not show a rapid decomposition of the structure in the soil after application, resulting in a reduction in effect. At the same time, after the charge neutralization-curing reaction occurs with urea, the reactive oxygen species originally having adsorption ability is weakened and becomes a dispensable group in the structure. This group will be degraded by peroxidase and superoxide dismutase in the soil or peeled off under the irradiation of ultraviolet rays, thus ensuring that it will not have side effects on the growth of crops.

[0061] The present invention also provides a preparation method of the synergistic urea described in the above technical solution, including the following steps:

[0062] Mix urea and the synergist solution and perform coating to obtain the synergistic urea.

[0063] In the present invention, the coating is preferably carried out at room temperature and under stirring. The present invention does not make specific limitations on the coating time, as long as the synergist solution can coat the urea.

[0064] After the coating, the present invention preferably further includes drying until there is no obvious water stain on the surface of the urea to obtain the synergistic urea.

[0065] The present invention also provides the application of the synergistic urea described in the above technical solution in the field of fertilizers.

[0066] The present invention does not make specific limitations on the application method of the synergistic urea in the field of fertilizers, and those skilled in the art can set it according to actual needs.

[0067] The following examples are used to illustrate in detail the synergistic urea, its preparation method and application provided by the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0068] Example 1

[0069] According to Figure 1 the flowchart to prepare the synergistic urea, specifically:

[0070] ① Place 4.27 kg of polyaspartic acid solution (the effective mass fraction of polyaspartic acid is 30.5%, the mass fraction of polymeric phosphate is 1.5%, and the number-average molecular weight of polyaspartic acid is 13 kD) in a 10-L beaker, add 106 g of 30% hydrogen peroxide and 106 mg of ferrous chloride, and then stir at 50 °C for 15 min to obtain activated polyaspartic acid. The content of active oxygen in the system is maintained at 30 - 40 mg / kg.

[0071] ② Add 1.08 kg of zinc iminodisuccinate solution (the effective content of zinc iminodisuccinate is 40%, and zinc ions account for 13.5% of the total effective content) and 0.65 kg of 40% mannan oligosaccharide solution into the above-mentioned activated polyaspartic acid at a rate of 1.5 L / h simultaneously, and maintain the stirring rate of the system at 120 r / min to obtain a synergist solution.

[0072] Take the synergist solution for content detection. Use DB13 / T2172-2015 Polyaspartic Acid (Salt) for Agricultural Use to determine the content of polyaspartic acid; use the spectrophotometer colorimetric method to determine the content of zinc iminodisuccinate, and use GB / T36861-2018 Determination of β-Mannanase Activity in Feed Additives to determine the content of mannan oligosaccharide.

[0073] The results are as follows: in the synergist solution, the mass fraction of polyaspartic acid is 21.71%, the mass fraction of zinc iminodisuccinate is 7.20%, and the mass fraction of mannan oligosaccharide is 4.33%.

[0074] Transfer 10 kg of the synergist solution prepared by the above preparation method completely into 990 kg of urea, stir until the synergist solution is completely wrapped on the surface of urea, and air-dry until there is no obvious water stain on the surface of urea to obtain synergistic urea Ⅰ.

[0075] Use the specified method of GB / T2440-2017 Urea to detect the urea content in the obtained synergistic urea. The results are as follows: the mass fraction of urea in the obtained synergistic urea Ⅰ is 99.66%, and the balance is 0.34% of the synergist.

[0076] Example 2

[0077] ① Place 6.52 kg of polyaspartic acid solution (the effective mass fraction of polyaspartic acid is 38%, the mass fraction of polymeric phosphate is 2.5%, and the number-average molecular weight of polyaspartic acid is 14 kD) in a 10-L beaker, add 162 g of 30% hydrogen peroxide and 162 mg of ferrous sulfate, and then stir at 40 °C for 20 min to obtain activated polyaspartic acid. The content of active oxygen in the system is maintained at 30 - 40 mg / kg.

[0078] ② Add 2.17 kg of zinc iminodisuccinate solution (the effective content of zinc iminodisuccinate is 40%, and zinc ions account for 13.5% of the total effective content) and 1.31 kg of mannan oligosaccharide solution with a mass fraction of 40% into the above-mentioned active polyaspartic acid at a rate of 1.5 L / h simultaneously, and maintain the stirring rate of the system at 120 r / min to obtain a synergist solution.

[0079] After testing, in the obtained synergist solution, the mass fraction of polyaspartic acid is 24.78%, the mass fraction of zinc iminodisuccinate is 8.68%, and the mass fraction of mannan oligosaccharide is 5.24%.

[0080] Transfer 10 kg of the synergist solution prepared by the above preparation method completely into 990 kg of urea, stir until the synergist solution is completely wrapped on the surface of urea, and air-dry until there is no obvious water stain on the surface of urea to obtain synergistic urea II.

[0081] After testing, in the obtained synergistic urea II, the mass fraction of urea is 99.59%, and the balance is 0.41% of the synergist.

[0082] Example 3

[0083] ① Put 2.46 kg of polyaspartic acid powder (the effective mass fraction of polyaspartic acid is 80.0%, the mass fraction of polyphosphate is 13.0%, and the number-average molecular weight of polyaspartic acid is 15 kD) and 3.04 L of water into a 10 L beaker, stir and dissolve, then add 61 g of hydrogen peroxide with a mass fraction of 30% and 61 mg of ferrous glycinate, and then stir at 60 °C for 10 min to obtain activated polyaspartic acid, and the content of active oxygen in the system is maintained at 30 - 40 mg / kg.

[0084] ② Add 1.11 kg of zinc iminodisuccinate solution (the effective content of zinc iminodisuccinate is 40%, and zinc ions account for 13.5% of the total effective content) and 1.33 kg of mannan oligosaccharide solution with a mass fraction of 40% into the above-mentioned active polyaspartic acid at a rate of 1.5 L / h simultaneously, and maintain the stirring rate of the system at 120 r / min to obtain a synergist solution.

[0085] After testing, in the obtained synergist solution, the mass fraction of polyaspartic acid is 24.60%, the mass fraction of zinc iminodisuccinate is 5.55%, and the mass fraction of mannan oligosaccharide is 6.65%.

[0086] Transfer 8 kg of the synergist solution prepared by the above preparation method completely into 992 kg of urea, stir until the synergist solution is completely wrapped on the surface of urea, and air-dry until there is no obvious water stain on the surface of urea to obtain synergistic urea III.

[0087] After detection, in the obtained synergistic urea Ⅲ, the mass fraction of urea is 99.67%, and the balance is 0.33% of the synergist.

[0088] In Comparative Example 1, polyaspartic acid was not activated.

[0089] Place 4.27 kg of polyaspartic acid solution (the effective mass fraction of polyaspartic acid is 30.5%, the mass fraction of polyphosphate is 1.5%, and the number-average molecular weight of polyaspartic acid is 13 kD) in a 10 L beaker and stir evenly; continue to add 1.08 kg of zinc iminodisuccinate solution (the effective mass fraction of zinc iminodisuccinate is 40%, and zinc ions account for 13.5% of the total effective content) and 0.65 kg of mannan oligosaccharide solution with a mass fraction of 40%, and maintain the stirring rate of the system at 120 r / min to obtain a synergist solution.

[0090] After detection, in the obtained synergist solution, the mass fraction of polyaspartic acid is 21.73%, the mass fraction of zinc iminodisuccinate is 7.24%, and the mass fraction of mannan oligosaccharide is 4.35%.

[0091] Completely transfer 10 kg of the synergist solution prepared by the above preparation method to 990 kg of urea, stir until the synergist solution is completely wrapped on the surface of the urea, and air-dry until there is no obvious water stain on the surface of the urea to obtain synergistic urea Ⅳ.

[0092] After detection, in the obtained synergistic urea Ⅳ, the mass fraction of urea is 99.65%, and the balance is 0.35% of the synergist.

[0093] In Comparative Example 2, mannan oligosaccharide is missing.

[0094] ① Place 4.27 kg of polyaspartic acid solution (the effective mass fraction of polyaspartic acid is 30.5%, the mass fraction of polyphosphate is 1.5%, and the number-average molecular weight of polyaspartic acid is 13 kD) in a 10 L beaker, add 106 g of hydrogen peroxide with a mass fraction of 30% and 106 mg of ferrous chloride, and then stir at 50 °C for 15 min to obtain activated polyaspartic acid, and the content of active oxygen in the system is maintained at 30 - 40 mg / kg.

[0095] ② Add 1.73 kg of zinc iminodisuccinate solution (the effective content of zinc iminodisuccinate is 40%, and zinc ions account for 13.5% of the total effective content) to the above active polyaspartic acid at a rate of 1.5 L / h, and maintain the stirring rate of the system at 120 r / min to obtain a synergist solution.

[0096] After detection, in the obtained synergist solution, the mass fraction of polyaspartic acid is 21.71%, and the mass fraction of zinc iminodisuccinate is 11.53%.

[0097] Transfer 10 kg of the synergist solution prepared by the above preparation method completely into 990 kg of urea, stir until the synergist solution is completely wrapped on the surface of urea, and air-dry until there is no obvious water stain on the surface of urea, thus obtaining synergistic urea Ⅴ.

[0098] After testing, in the obtained synergistic urea Ⅴ, the mass fraction of urea is 99.65%, and the balance is 0.35% of the synergist.

[0099] Comparative example 3 lacks zinc iminodisuccinate

[0100] ① Place 4.27 kg of a polyaspartic acid solution (the effective mass fraction of polyaspartic acid is 30.5%, the mass fraction of polymeric phosphate is 1.5%, and the number-average molecular weight of polyaspartic acid is 13 kD) in a 10 L beaker, add 106 g of hydrogen peroxide with a mass fraction of 30% and 106 mg of ferrous chloride, and then stir at 50 °C for 15 min to obtain activated polyaspartic acid, and the content of active oxygen in the system is maintained at 30 - 40 mg / kg.

[0101] ② Add 1.73 kg of a mannan oligosaccharide solution with a mass fraction of 40% to the above active polyaspartic acid at a rate of 1.5 L / h, and maintain the stirring rate of the system at 120 r / min to obtain a synergist solution.

[0102] After testing, in the obtained synergist solution, the mass fraction of polyaspartic acid is 21.71% and the mass fraction of mannan oligosaccharide is 11.53%.

[0103] Transfer 10 kg of the synergist solution prepared by the above preparation method completely into 990 kg of urea, stir until the synergist solution is completely wrapped on the surface of urea, and air-dry until there is no obvious water stain on the surface of urea, thus obtaining synergistic urea Ⅵ.

[0104] After testing, in the obtained synergistic urea Ⅵ, the mass fraction of urea is 99.65%, and the balance is 0.35% of the synergist.

[0105] Comparative example 4 lacks polyaspartic acid

[0106] Add 3.75 kg of a zinc iminodisuccinate solution (the effective content of zinc iminodisuccinate is 40%, and the zinc ion accounts for 13.5% of the total effective content) and 2.25 kg of a mannan oligosaccharide solution with a mass fraction of 40% to a 10 L beaker, and maintain the stirring rate of the system at 120 r / min to obtain a synergist solution.

[0107] After testing, in the obtained synergist solution, the mass fraction of zinc iminodisuccinate is 25% and the mass fraction of mannan oligosaccharide is 15%.

[0108] Transfer 10 kg of the synergist solution prepared by the above preparation method completely into 990 kg of urea, stir until the synergist solution is completely wrapped on the surface of urea, and air-dry until there is no obvious water stain on the surface of urea, then the synergistic urea VII is obtained.

[0109] After testing, in the obtained synergistic urea VII, the mass fraction of urea is 99.60%, and the balance is 0.40% of the synergist.

[0110] Comparative Example 5 Ratio out of range - Low content of polyaspartic acid

[0111] ① Place 2.50 kg of polyaspartic acid solution (the effective mass fraction of polyaspartic acid is 30.5%, the mass fraction of polyphosphate is 1.5%, and the number-average molecular weight of polyaspartic acid is 13 kD) in a 10 L beaker, add 106 g of hydrogen peroxide with a mass fraction of 30% and 106 mg of ferrous chloride, and then stir at 50 °C for 15 min to obtain activated polyaspartic acid. The content of active oxygen in the system is maintained at 30 - 40 mg / kg.

[0112] ② Add 2.30 kg of zinc iminodisuccinate solution (the effective content of zinc iminodisuccinate is 40%, and the zinc ion accounts for 13.5% of the total effective content) and 1.20 kg of mannan oligosaccharide solution with a mass fraction of 40% into the above-mentioned active polyaspartic acid at the same rate of 1.5 L / h, and maintain the stirring rate of the system at 120 r / min to obtain the synergist solution.

[0113] After testing, in the obtained synergist solution, the mass fraction of polyaspartic acid is 12.71%, the mass fraction of zinc iminodisuccinate is 15.33%, and the mass fraction of mannan oligosaccharide is 8.00%.

[0114] Transfer 10 kg of the synergist solution prepared by the above preparation method completely into 990 kg of urea, stir until the synergist solution is completely wrapped on the surface of urea, and air-dry until there is no obvious water stain on the surface of urea, then the synergistic urea VIII is obtained.

[0115] After testing, in the obtained synergistic urea VIII, the mass fraction of urea is 99.63%, and the balance is 0.37% of the synergist.

[0116] Comparative Example 6 Ratio out of range - High content of polyaspartic acid

[0117] ① Place 5.20 kg of polyaspartic acid solution (the effective mass fraction of polyaspartic acid is 40%, the mass fraction of polyphosphate is 1.5%, and the number-average molecular weight of polyaspartic acid is 13 kD) in a 10 L beaker, add 106 g of hydrogen peroxide with a mass fraction of 30% and 106 mg of ferrous chloride, and then stir at 50 °C for 15 min to obtain activated polyaspartic acid. The content of active oxygen in the system is maintained at 30 - 40 mg / kg.

[0118] ② Add 0.50 kg of zinc iminodisuccinate solution (the effective content of zinc iminodisuccinate is 40%, and zinc ions account for 13.5% of the total effective content) and 0.30 kg of mannan oligosaccharide solution with a mass fraction of 40% into the above-mentioned active polyaspartic acid at a rate of 1.5 L / h simultaneously, and maintain the stirring rate of the system at 120 r / min to obtain a synergist solution.

[0119] After testing, in the obtained synergist solution, the mass fraction of polyaspartic acid is 34.67%, the mass fraction of zinc iminodisuccinate is 3.33%, and the mass fraction of mannan oligosaccharide is 2.00%.

[0120] Transfer 10 kg of the synergist solution prepared by the above preparation method completely into 990 kg of urea, stir until the synergist solution is completely wrapped on the surface of urea, and air-dry until there is no obvious water stain on the surface of urea to obtain synergistic urea IX.

[0121] After testing, in the obtained synergistic urea IX, the mass fraction of urea is 99.58%, and the balance is 0.42% of the synergist.

[0122] Application example: Field test of synergistic urea

[0123] Conduct field tests on the synergistic ureas prepared in Example 1 and Comparative Examples 1 - 6. When sowing, apply ordinary compound fertilizer (nutrient content N - P 2 O 5 - K 2 O is 15% - 15% - 15%) at 750 kg / hm 2 , and apply each synergistic urea at a reduced - rate fertilization test of 180 kg / hm 2 to the top - dressing of summer maize in different test areas at the 6 - 7 leaf stage of maize (i.e., the large - trumpet - mouth stage), denoted as T1, P1 - P6; at the same time, set up a field control test of ordinary urea. When sowing, apply fertilizer as above, and at the 6 - 7 leaf stage, apply ordinary urea at reduced - rate (180 kg / hm 2 ) and normal - rate (225 kg / hm 2 ) fertilization to the top - dressing of summer maize in the control test areas, denoted as CK 1 , CK 2 ; all the above treatments are respectively recorded as individual test areas, and the area of each test area is 300 m 2 , each treatment is repeated 3 times, and all test areas are arranged in a randomized block design (randomized block design means random arrangement, which is used to eliminate experimental errors).

[0124] This experiment was conducted in Yuanshi County, Shijiazhuang City, Hebei Province (114°5231′49E, 37°46′27N) in 2024. The experimental area is a typical brown soil formed in the alluvial plain, with soil organic matter content of 1.73%, total nitrogen of 1.22g / kg, available phosphorus of 30.87mg / kg, and available potassium of 116.82mg / kg. It is a low organic matter, medium nitrogen, phosphorus and potassium level plot; the experimental time is from the trumpet stage of summer corn to corn harvest, and the yield of each plot is measured separately. The determination of N in the measured items refers to the relevant provisions of the "Tutorial on Physical and Chemical Analysis of Soil, Water and Plants", and the nutrient recovery rate is calculated with reference to the nutrient usage to characterize the fertilizer utilization rate. The other indicators are designed and analyzed with reference to the relevant requirements of the general agronomy introduction, and then the comprehensive statistical analysis method is used to verify the effect of synergistic urea, and the SPSS20.0 data analysis system is used for one-way analysis of variance and the Dunckan method is used for significant difference test; the comprehensive data results are shown in Table 1.

[0125] Table 1 Comparison of experimental data on urea-enhanced summer corn topdressing

[0126]

[0127]

[0128] In the data in the above table, in terms of summer corn yield, the difference between T1 treatment and P5 and P6 treatments is basically significant, and the difference is extremely significant compared with other treatments, indicating that urea in T1 treatment has a good yield-increasing effect. At the same time, the technicians also found that this treatment achieved the effect of reducing weight and increasing yield (by comparing T1 with CK1 and CK2); by comparing the thousand-grain weight data of different treatments, the conclusion is basically consistent with the yield data; continuing to compare the number of grains per ear data, it is found that the gap between the treatments is relatively close; continuing to analyze the N nutrient recovery rate data, it is found that the utilization rate of T1 treatment is now much higher than others (T1 treatment is better than P6 treatment by 5.81%, T1 treatment is better than CK2 treatment by 13.73%, T1 treatment is better than CK1 treatment by 22.51%), and its trend is similar to the yield increase trend of corn (T1 treatment is better than P6 treatment by 2.96%, T1 treatment is better than CK2 treatment by 18.26%, T1 treatment is better than CK1 treatment by 21.75%).

[0129] By comparing the corresponding data of the above four indicators, it can be judged that the synergistic urea produced by T1 treatment can effectively increase the yield of corn. The analysis of its yield increase ways is as follows: ① In T1 treatment, substances such as activated polyaspartic acid, iminodisuccinic acid chelated zinc, and mannan oligosaccharide all played very good functions and achieved a balance in terms of quick-acting property and long-lasting period; in the corresponding P2-P5 treatments, three of these substances were missing, and their relevant data were significantly different from those of T1 treatment; ② In T1 treatment, the ratio of the three substances is also an important part of its effectiveness; in the corresponding P5-P6 treatments, although the total amount of synergist is equal to that of T1 treatment, its effect still did not reach the T1 level, thus proving the key between long-lasting property and quick-acting property; ③ In addition, activated polyaspartic acid is also crucial. By comparing T1 treatment with P1 treatment, its necessity can be known. Through the above analysis of the yield data, it is the overall function of the synergist in T1 treatment that realizes the yield increase of corn, which makes T1 treatment significantly superior to other treatments. In addition, in this experiment, the technicians also found that this synergist mainly increases the yield of corn by increasing the 1000-grain weight, that is, through the accumulation of nutrients; the main reason for this phenomenon is that after using this synergist, it can promote the absorption of nutrients by corn plants and the transportation and storage of photosynthesis-synthesized substances. And this conclusion is obtained by the technicians' analysis of the N nutrient recovery rate data.

[0130] In summary, the synergistic urea of the present invention can significantly improve nitrogen utilization rate, and at the same time continuously stimulate plant growth and nutrient absorption through the stable combination formed by it, thereby significantly increasing crop yield.

[0131] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A synergistic urea, characterized in that: The following components are included in mass percentage: Urea 98.8-99.7%, synergist 0.3-1.2%; The synergists include polyaspartic acid, zinc iminodisuccinate and manno-oligosaccharides.

2. The synergistic urea according to claim 1, characterized in that: The mass ratio of the polyaspartic acid, zinc iminodisuccinate and manno-oligosaccharide is 2.5-5:1:0.6-1.

2.

3. The synergistic urea according to claim 1, characterized in that: The number average molecular weight of the polyaspartic acid is 10-15 kD.

4. The enhanced urea according to claim 1, characterized in that: The synergist is used in the form of a synergist solution, in which the mass fraction of polyaspartic acid is 15-25%.

5. The enhanced urea according to claim 4, characterized in that: The preparation method of the synergist solution comprises the following steps: Activating the polyaspartic acid to obtain activated polyaspartic acid; The activated polyaspartic acid, zinc iminodisuccinate and manno-oligosaccharide are mixed and adsorbed to obtain the synergist solution.

6. The enhanced urea according to claim 5, characterized in that: The activation reagent includes hydrogen peroxide and ferrous salt; the mass fraction of the hydrogen peroxide is 30%; The ferrous salt includes one or more of ferrous chloride, ferrous sulfate, ferrous glycinate and ferrous citrate; The mass ratio of the polyaspartic acid, hydrogen peroxide and ferrous salt is 150-500:15:0.

015.

7. The enhanced urea according to claim 5 or 6, characterized in that: The activation temperature is 40-60° C. and the activation time is 10-20 minutes.

8. The enhanced urea according to claim 5, characterized in that: The zinc iminodisuccinate is used in the form of a zinc iminodisuccinate solution, wherein the mass fraction of the zinc iminodisuccinate in the zinc iminodisuccinate solution is 30 to 50%; The manno-oligosaccharide is used in the form of a manno-oligosaccharide solution, and the mass fraction of the manno-oligosaccharide solution is 30-50%; The adsorption is carried out under stirring conditions, the stirring speed is 100-150 r / min, and the time is 15-30 min.

9. The method for preparing the enhanced urea according to any one of claims 1 to 8, characterized in that: The following steps are involved: The urea and the synergist solution are mixed and packaged to obtain the synergist urea.

10. Use of the enhanced urea according to any one of claims 1 to 8 or the enhanced urea prepared by the preparation method according to claim 9 in the field of fertilizers.

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