阅读说明：本技术 具有在同一颗粒内分开的尿素酶抑制剂和硝化抑制剂的增效肥料 (Synergistic fertilizer with urease inhibitor and nitrification inhibitor separated in the same granule ) 是由 拉维·赫格德 拉贾马莱斯沃拉玛·科里佩利 钱德拉·莫汉纳 拉达·阿查纳特 沙米克·古普塔 于 2018-04-12 设计创作，主要内容包括：本文描述了具有尿素酶抑制剂和硝化抑制剂的肥料颗粒。肥料颗粒可包括包含尿素酶抑制剂的核颗粒和包含硝化抑制剂的外层。(Fertilizer granules having a urease inhibitor and a nitrification inhibitor are described herein. The fertilizer granule may comprise a core granule comprising a urease inhibitor and an outer layer comprising a nitrification inhibitor.)

1. A fertilizer granule comprising:

a core particle comprising a urease inhibitor and a binder; and

a nitrogen-containing fertilizer composition in contact with the outer surface of the core particle and comprising a nitrification inhibitor.

2. The fertilizer granule of claim 1, wherein the urease inhibitor comprises N- (N-butyl) thiophosphoric triamide (NBTPT) and the nitrification inhibitor comprises dicyandiamide (DCD).

3. The fertilizer granule of claim 1, wherein the binder comprises one or more of plaster of paris, flour, biodegradable bleached wheat flour, starch, gluten, kaolin clay, bentonite clay, or colloidal silica.

4. The fertilizer granule of claim 1, wherein the binder is present in the core granule in an amount of 10% to 99% by weight of the core granule.

5. The fertilizer granule of claim 1, wherein the core granule further comprises a filler in an amount of greater than 0 to 60 wt% of the core granule, wherein the filler comprises silica, distillers dried grains with solubles (DDGS), CaCO₃One or more than one of chalk powder or rice bran.

6. The fertilizer particle of claim 1, wherein the core particle further comprises a pH buffer in an amount from 5 wt% to 60 wt% of the core particle, wherein the pH buffer comprises chalk powder, CaCO₃、MgO、KH₂PO₄、NaHCO₃、Na₂CO₃、K₂CO₃Or MgCO₃One or more than one.

7. The fertilizer granule of claim 1, wherein the core granule further comprises a polymeric thickener in an amount from 0.1% to 1% by weight of the core granule, wherein the polymeric thickener comprises hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose, polyethylene glycol (PEG), guar gum, locust bean gum, xanthan gum, natural gum, or hydroxyethyl cellulose.

8. The fertilizer granule of claim 1, wherein the amount of urease inhibitor in the core granule is between 1% and 5% by weight of the core granule and the amount of nitrification inhibitor in the nitrogen-containing fertilizer composition is between 0.5% and 2% by weight of the nitrogen-containing fertilizer composition.

9. The fertilizer granule of claim 1, wherein the amount of urease inhibitor in the nitrogen-containing fertilizer composition is no more than 0.01 wt% of the nitrogen-containing fertilizer composition and the amount of nitrification inhibitor in the core granule is no more than 0.01 wt% of the core granule.

10. The fertilizer granule of claim 1, wherein the nitrogen-containing fertilizer composition substantially surrounds the core granule or completely surrounds the core granule.

11. The fertilizer granule of claim 1, wherein the core granule has a diameter of 0.5mm to 2mm and the nitrogen-containing fertilizer composition has a thickness of 1mm to 6 mm.

12. The fertilizer granule of claim 1, wherein the core granule is an extruded granule.

13. The fertilizer granule of claim 1, wherein the nitrogen-containing fertilizer composition comprises urea.

14. The fertilizer granule of claim 1, wherein at least 90% of the urease inhibitor remains after the fertilizer granule is stored in a sealed container at 22 ℃ for 30 days.

15. The fertilizer granule of claim 1, comprising 1 to 5 wt binder, 1 to 5 wt filler, 1 to 5 wt pH buffer, 0.01 to 0.1 wt polymeric thickener, 0.05 to 0.2 wt urease inhibitor, 90 to 95 wt nitrogen fertilizer, and 0.5 to 2 wt nitrification inhibitor.

16. A fertilizer composition comprising:

the fertilizer granule of claim 1, and

other fertilizer particles comprising a core and a shell, wherein the core comprises urea and at least one of a urease inhibitor or a nitrification inhibitor, and at least one of a binder, a filler, a pH buffer, or a polymeric thickener, and wherein the shell comprises urea and a nitrification inhibitor.

17. A fertilizer granule comprising:

(a) a core particle comprising N- (N-butyl) thiophosphoric triamide (NBTPT) and a binder; and

(b) a shell comprising a solid urea composition comprising dicyandiamide (DCD).

18. A method of making a fertilizer granule, the method comprising:

providing a core particle comprising N- (N-butyl) thiophosphoric triamide (NBTPT) and a binder;

providing a fertilizer composition comprising molten urea and dicyandiamide (DCD); and

contacting the core particle with a fertilizer composition under conditions sufficient to form a solid fertilizer particle comprising a solidified fertilizer composition in contact with an outer surface of the core particle.

19. The method of claim 18, wherein contacting the core particle with the fertilizer composition comprises spraying the fertilizer composition onto the core particle.

20. A method according to claim 18 or 19, wherein the core particle is made by extruding a composition comprising 35 to 55 wt% binder, 35 to 50 wt% of an agent that is both a filler and a buffer, 0.1 to 1 wt% of a polymeric thickener, and 1 to 2.2 wt% of NBTPT.

Background

A. Field of the invention

The present invention relates generally to fertilizer granules comprising a urease inhibitor and a nitrification inhibitor. The urease inhibitor and nitrification inhibitor are separated from each other within the granule, wherein the urease inhibitor is included in the core granule and the nitrification inhibitor is included in a solid composition at least partially surrounding the core granule.

B. Description of the related Art

To increase crop yields and meet the increasing demand of the population, more fertilizers are used in agriculture. However, continued use of fertilizers can result in nutrient imbalances and a decrease in soil fertility. In addition, since urea fertilizers are rapidly hydrolyzed and nitrified in soil by soil bacteria, the widespread use of urea fertilizers can lead to deterioration of soil health and other environmental problems, such as greenhouse gas emissions and groundwater pollution.

The urea enzyme inhibitor and the nitrification inhibitor are added into the fertilizer to offset the hydrolysis and nitrification of urea in soil. Urease inhibitors reduce the amount of urea hydrolysis and thus the amount of nitrogen lost via ammonia volatilization. Nitrification inhibitors can reduce the rate of conversion of ammonium salts to nitrates, which also reduces the amount of nitrogen lost. Besides urea, the nitrification inhibitor can also effectively improve the utilization rate of various nitrogen fertilizers.

Although urease inhibitors and nitrification inhibitors have been used in fertilizers to address the problem of urea hydrolysis and nitrification, there are certain difficulties with the use of these inhibitors. One problem is that certain inhibitors are sensitive to heat, which complicates the production of fertilizers containing such inhibitors. For example, the addition of heat-sensitive inhibitors to molten urea prior to granulation can result in substantial degradation of the inhibitor, as described in Soil utilization and Management (Soil Use & Management)24:246 (2008). To compensate for this problem, some fertilizer manufacturers may add an excess of inhibitor to the urea melt, which increases the production cost of the fertilizer. Another problem is that some combinations of inhibitors may be incompatible if contained in the same particle. For example, the inventors of the present application have observed that the nitrification inhibitor dicyandiamide (DCD) causes stability problems if combined with the urease inhibitor N- (N-butyl) thiophosphoric triamide (NBTPT). Without wishing to be bound by theory, it is well known that DCD increases degradation of NBTPT under storage conditions, which is sensitive to both heat and moisture.

Disclosure of Invention

The following discloses a solution to the above-mentioned problem. In some embodiments, the solution consists in providing fertilizer granules in which the urease inhibitor and nitrification inhibitor are separated from each other within the granules. Such fertilizer granules may include a core granule comprising a urease inhibitor and an outer layer or shell comprising a nitrification inhibitor. In such granules, the urease inhibitor and nitrification inhibitor may be separated from each other, thereby preventing any degradation that may have between the inhibitors. Furthermore, the manufacturing process to prepare such particles may provide protection against thermal degradation for the inhibitor contained in the core particles. This is achieved by adding a heat sensitive inhibitor (e.g. NBTPT) to the core particle rather than to the relatively hot composition (e.g. molten urea) during the preparation of the fertilizer particle. Other ingredients in the core particle help provide a buffer to heat during the manufacturing process, thereby reducing the amount of inhibitor lost to thermal degradation.

The fertilizer granules disclosed herein comprise: (a) a core particle comprising a urease inhibitor and a binder; and (b) a nitrogen-containing fertilizer in contact with the outer surface of the core particle, and may include a nitrification inhibitor. In some embodiments, the urease inhibitor may include, for example, N- (N-butyl) thiophosphoric triamide (NBTPT). In some embodiments, the nitrification inhibitor may include, for example, dicyandiamide (DCD). In some embodiments, the amount of urease inhibitor in the core particle ranges from about 1% to 20% by weight of the core particle. In some embodiments, the amount of urease inhibitor in the core particle is about 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 6.0 wt%, 7.0 wt%, 8.0 wt%, 9.0 wt%, 10.0 wt%, or between any two of these values of the core particle. Preferably, the amount is about 0.1 to 5 wt%. In some embodiments, the amount of nitrification inhibitor in the nitrogen-containing fertilizer composition is about 0.5 wt% to 10 wt% of the nitrogen-containing fertilizer composition. In some embodiments, the amount of nitrification inhibitor in the nitrogen-containing fertilizer composition is about 0.1 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, 0.9 wt.%, 1.0 wt.%, 1.1 wt.%, 1.2 wt.%, 1.3 wt.%, 1.4 wt.%, 1.5 wt.%, 1.6 wt.%, 1.7 wt.%, 1.8 wt.%, 1.9 wt.%, 2.0 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, or 10 wt.% or between any two of these values of the nitrogen-containing fertilizer composition. Preferably, the amount is about 0.1 to 2 wt%. In some embodiments, the core particle does not include a nitrification inhibitor, including no more than trace amounts of nitrification inhibitor and/or no more than 0.01 wt.%, 0.05 wt.%, or 0.1 wt.% of nitrification inhibitor. In some embodiments, the core may comprise a nitrification inhibitor and the nitrogen fertilizer comprises a urease inhibitor. In some embodiments, neither the core nor the nitrogen-containing fertilizer composition comprises a urease inhibitor. In some embodiments, neither the core nor the nitrogen-containing fertilizer composition contains a nitrification inhibitor. In some embodiments, the urease inhibitor is absent from the core particle, including no more than a trace amount of urease inhibitor and/or no more than 0.01 wt%, 0.05 wt%, or 0.1 wt% urease inhibitor. In some embodiments, the nitrogen-containing fertilizer composition is free of urease inhibitor, including no more than a trace amount of urease inhibitor and/or no more than 0.01 wt%, 0.05 wt%, or 0.1 wt% urease inhibitor. In some embodiments, the nitrogen-containing fertilizer composition is absent nitrification inhibitors, including no more than trace amounts of nitrification inhibitors and/or no more than 0.01 wt.%, 0.05 wt.%, or 0.1 wt.% nitrification inhibitors.

In some embodiments, the core particle may further comprise other materials in addition to the urease inhibitor and the binder, such as fillers, pH balancing agents, and polymeric thickeners.

The binder in the core particle may help prevent the core particle from cracking or chipping during the manufacturing process or during storage. In some embodiments, the binder may include one or more of plaster of paris, flour, biodegradable bleached wheat flour, starch, gluten, kaolin, bentonite, or colloidal silica, including mixtures thereof. Other suitable adhesives known in the art may also be used. In some embodiments, the binder is present in the core particle in an amount from 10 to 99 weight percent of the core particle. In some embodiments, the binder is present in the core particle in an amount of about 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 98 wt%, or wt% of the core particle or between any two of these values.

In some embodiments, the filler in the core particle may comprise one or more of silica, distillers dried grains with solubles (DDGS), or rice bran, or a mixture thereof. Other suitable fillers known in the art may also be used. In some embodiments, the filler is present in the core particle in an amount from greater than 0% to 60% by weight of the core particle. In some embodiments, the filler is present in the core particle in an amount of about 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 percent by weight of the core particle or between any two of these values.

In some embodiments, the pH buffering agent in the core particle may be one or more than one of chalk powder, CaCO₃、Na₂CO₃、K₂CO₃、MgO、KH₂PO₄、NaHCO₃Or MgCO₃Or mixtures thereof. In some embodiments, the filler is present in the core particle in an amount of about 5% to 60% by weight of the core particle. In some embodiments, the filler is present in the core particle in an amount of about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 percent by weight of the core particle, or between any two of these values. In some embodiments, the pH buffering agent may also act as a filler. For example, in some embodiments, CaCO₃Both as a filler and as a pH buffer, and no other filler or pH buffer is included in the core particle.

In some embodiments, the polymeric thickener in the core particle may be one or more than one of hydroxypropyl methylcellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol (PEG), guar gum, locust bean gum, xanthan gum, other natural gums or synthetic polymers based on acrylates, Polyacrylamides (PAM), PVP, or a combination of synthetic polymers and carbomers. In some embodiments, the polymeric thickener is present in an amount of 0.1 to 1% by weight of the core particle. In some embodiments, the polymeric thickener is present in an amount of about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 10 percent by weight of the core particle or between any two of these values.

In some embodiments, the core particle may comprise 35 to 55 wt% of a binder, 35 to 45 wt% of a filler, 35 to 45 wt% of a pH buffer, 0.1 to 1 wt% of a polymeric thickener, and 1 to 2.2 wt% of a urease inhibitor.

In some embodiments, the fertilizer granule may include the following ingredients in the indicated amounts, expressed as weight percentages relative to the total fertilizer granule ingredients: 1 to 5 wt% of a binder, 1 to 5 wt% of a filler, 1 to 5 wt% of a pH buffer, 0.01 to 0.1 wt% of a polymer, 0.05 to 0.2 wt% of a urease inhibitor, 90 to 95 wt% of a nitrogen fertilizer, and 0.5 to 2 wt% of a nitrification inhibitor.

In some embodiments, the nitrogen-containing fertilizer composition substantially or completely surrounds the core particle. In some embodiments, the nitrogen-containing fertilizer composition covers at least 90%, 95%, or 99% of the surface of the core particle. In embodiments where the urea-containing composition completely surrounds the core particle, the nitrogen-containing fertilizer composition covers 100% of the surface of the core particle. In some embodiments, the nitrogen-containing fertilizer composition comprises urea. In some embodiments, the amount of urea in the nitrogen-containing fertilizer composition is from 10 wt% to 99.9 wt% of the nitrogen-containing fertilizer composition. In some embodiments, the amount of urea present in the nitrogen-containing fertilizer composition is about 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 99 wt%, or 99.9 wt%, or between any two of these values.

In some embodiments, the fertilizer particle is a core-shell particle comprising: (a) a core particle comprising NBTPT and a binder; and (b) a urea-containing composition in contact with the outer surface of the core particle and which may include DCD. As used herein, a core-shell particle is a particle in which the solid particles are surrounded by a different solid composition. In some embodiments, the shell is a layer of the solid urea-comprising composition that substantially or completely surrounds the core particle.

Also disclosed is a fertilizer granule comprising a core particle and a shell surrounding the core particle, wherein the core particle can comprise (a) a urease inhibitor or nitrification inhibitor, and (b) a binder or urea. In such embodiments, the core particle may include urea and a urease inhibitor, urea and a nitrification inhibitor, a binder and a urease inhibitor, or a binder and a nitrification inhibitor. In these embodiments, the shell portion of the granule may include a urease inhibitor, a nitrification inhibitor, a binder, and two substances not present in the urea core granule. For example, if the core particle comprises urea and a urease inhibitor, the shell may comprise a binder and a nitrification inhibitor; alternatively, if the core particle comprises a binder and a nitrification inhibitor, the shell may comprise urea and a urease inhibitor. In some cases, the core particle can include at least one of urea, a urease inhibitor, a nitrification inhibitor, and a binder, filler, pH buffer, and/or polymer thickener. Such core particles may be fertilized with urea to form a shell substantially surrounding the core. The urea may comprise a fertilizer active, such as DCD. In some cases, the urea does not contain a fertilizer active. Alternatively, the core particle may be incorporated into a urea matrix containing a fertilizer active ingredient, such as DCD. In other cases, the urea matrix does not contain a fertilizer active.

Embodiments of the fertilizer particles disclosed herein can include various arrangements and proportions of the core particle and the urea-containing composition. In some embodiments, there are multiple core particles in one fertilizer granule. In some embodiments, the core particle has a diameter of about 0.5mm to 2 mm. In some embodiments, the core particle has a diameter of about 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 3.0mm, 4.0mm, or 5.0mm or between any two of these values. In some embodiments, the nitrogen-containing fertilizer composition has a thickness of about 1mm to 6 mm. In some embodiments, the nitrogen-containing fertilizer composition has a thickness of about 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 3.0mm, 4.0mm, 5.0mm, 6.0mm, 7.0mm, or 8.0mm or between any two of these values. In some embodiments, the nitrogen-containing fertilizer composition is a solid that is formed by spraying a molten form of the nitrogen-containing fertilizer composition onto the core particle and allowing the molten nitrogen-containing fertilizer composition to cool and solidify. In some embodiments, the molten nitrogen fertilizer-containing composition is a molten urea-containing composition. In some embodiments, the weight ratio of the urea-containing composition to the core particle in the fertilizer particle is about 2:1, 5:1, 10:1, 15:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, or 100:1, or between any two of these values. In some embodiments, the urea-containing composition comprises about 70%, 80%, 90%, 95%, or 99%, or between any two of these values, by weight of the fertilizer particle. In some embodiments, the fertilizer granule has a diameter of 0.5mm to 8 mm. In some embodiments, the fertilizer granule has a diameter of about 0.2mm, 0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm, 6.0mm, 7.0mm, 8.0mm, 9.0mm, or 10.0mm or between any two of these values. In some embodiments, the core particle is an extruded particle.

Embodiments of the fertilizer granules disclosed herein are characterized by stability of nitrogen in the granules when exposed to soil. Due to the efficient distribution of urease inhibitor and nitrification inhibitor in the granules, the fertilizer granules described herein suffer less nitrogen loss due to hydrolysis and nitrification than would otherwise be the case. In some embodiments, less than 20% by weight of the nitrogen in the fertilizer granule is lost via ammonia volatilization after exposure to greenville soil for 20 days. In some embodiments, the amount of nitrogen in the granular fertilizer lost due to ammonia volatilization after 20 days of exposure to greenville soil is less than 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 percent by weight, or between any two of these values. In some embodiments, less than 20% by weight of nitrogen is lost in the granular fertilizer after 20 days of exposure to clauli soil. In some embodiments, the amount of nitrogen lost in the granular fertilizer after 20 days of exposure to clauli soil is less than 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 weight percent, or between any two of these values.

Embodiments of the fertilizer granules disclosed herein are also characterized by the stability of urease inhibitors, such as NBTPT, in the granules. This can be measured by a stability test which involves measuring the concentration of urease inhibitor in the granules before and after storage under controlled conditions for a certain period of time. In some embodiments, the fertilizer granules retain at least 90% of the urease inhibitor after 30 days of storage at 22 ℃ in the closed container as compared to before storage. In some embodiments, the fertilizer granule leaves at least about 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% urease inhibitor, or a remainder between any two of these values.

Also disclosed is a method of enhancing plant growth by applying to the soil an effective amount of a composition containing any of the granular fertilizers described herein.

Also disclosed is a method of making a fertilizer granule, which may include: providing a core particle comprising NBTPT and a binder; providing a fertilizer composition comprising molten urea and DCD; contacting the core particle with a fertilizer composition under conditions sufficient to form a solid fertilizer particle comprising a solidified fertilizer composition in contact with an outer surface of the core particle. In some casesIn embodiments, contacting the core particle with the fertilizer composition comprises spraying the fertilizer composition in molten form onto the core particle and allowing the fertilizer composition to cool and solidify. This can be achieved using, for example, granulation equipment known in the art. In some embodiments, DCD alone or in combination with other ingredients is added directly to the molten urea prior to contacting the core particle with the molten urea composition. In some embodiments, the amount of NBTPT in the core particle is about 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, or 20 percent by weight of the core particle or between any two of these values. In some embodiments, the amount of DCD in the fertilizer composition is about 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 6.0 wt%, 7.0 wt%, 8.0 wt%, 9.0 wt%, 10.0 wt%, 11.0 wt%, 12.0 wt%, 13.0 wt%, 14.0 wt%, 15.0 wt%, 16.0 wt%, 17.0 wt%, 18.0 wt%, 19.0 wt%, 20.0 wt%, 25.0 wt%, 30.0 wt%, 35.0 wt%, 40.0 wt%, 45.0 wt%, or 50 wt% of the fertilizer composition or between any two of these values. In some embodiments, the method of making a fertilizer granule may further comprise making the core granule by extruding a composition comprising the binder and NBTPT, and optionally the filler, pH buffer, and/or polymeric thickener. In some embodiments, the core particle is made by extruding a composition that may comprise 35 to 55 wt% binder, 0 to 45 wt% filler, 0 to 45 wt% pH buffer, 0.1 to 1 wt% polymeric thickener, and 1 to 2.2 wt% NBTPT. In some other embodiments, the core particle is made by extruding a composition, which composition isThe article may comprise 35 to 55 wt% binder, 35 to 50 wt% of an agent that is both a filler and a buffer, 0.1 to 1 wt% of a polymeric thickener, and 1 to 2.2 wt% of NBTPT. For example, many fillers known in the art may be used as buffering agents and vice versa. In some of these embodiments, CaCO₃Both as a filler and as a pH buffer.

The following embodiments 1 to 20 of the present invention are also disclosed. Embodiment 1 is a fertilizer granule comprising: a core particle comprising a urease inhibitor and a binder; and a nitrogen-containing fertilizer composition in contact with the outer surface of the core particle and comprising a nitrification inhibitor. Embodiment 2 is the fertilizer granule of embodiment 1, wherein the urease inhibitor comprises N- (N-butyl) thiophosphoric triamide (NBTPT) and the nitrification inhibitor comprises dicyandiamide (DCD). Embodiment 3 is the fertilizer granule of embodiment 1 or 2, wherein the binder comprises one or more of plaster of paris, flour, biodegradable bleached wheat flour, starch, gluten, kaolin, bentonite, or colloidal silica. Embodiment 4 is the fertilizer particle of any one of embodiments 1-3, wherein the binder is present in the core particle in an amount of 10 wt% to 99 wt% of the core particle. Embodiment 5 is the fertilizer granule of any one of embodiments 1 to 4, wherein the core granule further comprises a filler in an amount of greater than 0 to 60 wt% of the core granule, wherein the filler comprises silica, distillers dried grains with solubles (DDGS), CaCO₃One or more than one of chalk powder or rice bran. Embodiment 6 is the fertilizer particle of any one of embodiments 1 to 5, wherein the core particle further comprises a pH buffer in an amount from 5 wt% to 60 wt% of the core particle, wherein the pH buffer comprises chalk powder, CaCO₃、MgO、KH₂PO₄、NaHCO₃、Na₂CO₃、K₂CO₃Or MgCO₃One or more than one. Embodiment 7 is the fertilizer particle of any one of embodiments 1 to 6, wherein the core particle further comprises a polymeric thickener in an amount of 0.1 to 1 wt% of the core particle, wherein the polymeric thickener comprises hydroxypropyl methylMethylcellulose (HPMC), carboxymethylcellulose, polyethylene glycol (PEG), guar gum, locust bean gum, xanthan gum, natural gums or hydroxyethylcellulose. Embodiment 8 is the fertilizer granule of any one of embodiments 1 to 7, wherein the amount of urease inhibitor in the core granule is 1 wt% and 5 wt% of the core granule and the amount of nitrification inhibitor in the nitrogen-containing fertilizer composition is 0.5 wt% to 2 wt% of the nitrogen-containing fertilizer composition. Embodiment 9 is the fertilizer granule of any one of embodiments 1 to 8, wherein the amount of urease inhibitor in the nitrogen-containing fertilizer composition is no more than 0.01 wt% of the nitrogen-containing fertilizer composition and the amount of nitrification inhibitor in the core granule is no more than 0.01 wt% of the core granule. Embodiment 10 is the fertilizer granule of any one of embodiments 1 to 9, wherein the nitrogen-containing fertilizer composition substantially surrounds the core granule or completely surrounds the core granule. Embodiment 11 is the fertilizer granule of any one of embodiments 1 to 10, wherein the core granule has a diameter of 0.5mm to 2mm and the nitrogen-containing fertilizer composition has a thickness of 1mm to 6 mm. Embodiment 12 is the fertilizer granule of any one of embodiments 1 to 11, wherein the core granule is an extruded granule. Embodiment 13 is the fertilizer granule of any one of embodiments 1 to 12, wherein the nitrogen-containing fertilizer composition comprises urea. Embodiment 14 is the fertilizer granule of any one of embodiments 1 to 13, wherein at least 90% of the urease inhibitor remains after the fertilizer granule is stored in a sealed container at 22 ℃ for 30 days. Embodiment 15 is the fertilizer granule of any one of embodiments 1 to 14, comprising 1 to 5 wt% of a binder, 1 to 5 wt% of a filler, 1 to 5 wt% of a pH buffer, 0.01 to 0.1 wt% of a polymeric thickener, 0.05 to 0.2 wt% of a urease inhibitor, 90 to 95 wt% of a nitrogen fertilizer, and 0.5 to 2 wt% of a nitrification inhibitor. Embodiment 16 is a fertilizer composition comprising the fertilizer particle of any one of embodiments 1-15 and another fertilizer particle comprising a core and a shell, wherein the core comprises urea and at least one of a urease inhibitor or a nitrification inhibitor and at least one of a binder, a filler, a pH buffer, or a polymeric thickener, and wherein the shell comprises urea and a nitrification inhibitor. Embodiment 17 is aA fertilizer granule comprising: (a) a core particle comprising NBTPT and a binder; and (b) a shell comprising a solid urea composition comprising DCD. Embodiment 18 is a method of making a fertilizer granule, the method comprising: providing a core particle comprising NBTPT and a binder; providing a fertilizer composition comprising molten urea and DCD; contacting the core particle with a fertilizer composition under conditions sufficient to form a solid fertilizer particle comprising a solidified fertilizer composition in contact with an outer surface of the core particle. Embodiment 19 is the method of embodiment 18, wherein contacting the core particle with the fertilizer composition comprises spraying the fertilizer composition onto the core particle. Embodiment 20 is the method of embodiment 18 or 19, wherein the core particle is made by extruding a composition comprising 35 to 55 weight percent of a binder, 35 to 50 weight percent of an agent that is both a filler and a buffer, 0.1 to 1 weight percent of a polymeric thickener, and 1 to 2.2 weight percent of NBTPT.

As used herein, the term "fertilizer particle" refers to a discrete particle that includes both a core particle and a solid composition in contact with the outer surface of the core particle and covering at least a portion of the surface of the core particle. "fertilizer granules" may also be referred to as granules, fertilizer granules, pellets or fertilizer pellets.

The term "about" or "approximately" is defined as being close as understood by one of ordinary skill in the art. In one non-limiting embodiment, the term is defined as within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

The terms "weight percent," "volume percent," or "mole percent," respectively, refer to the weight percent of a component, the volume percent of a component, or the mole percent of a component, based on the total weight of materials, the total volume of materials, or the total molar amount of the components included. In one non-limiting example, 10 grams of a component in 100 grams of material is 10 weight percent of the component.

The term "substantially" is defined as including ranges within 10%, within 5%, within 1%, or within 0.5%.

The terms "inhibit" or "reduce" or "prevent" or "avoid" when used in the claims and/or the specification includes any measurable reduction or complete inhibition to achieve a desired result.

As used in this specification and/or in the claims, the term "effective" means suitable for achieving a desired, expected, or expected result.

When used in conjunction with any of the terms "comprising," including, "" containing, "or" having "in the claims or specification, the singular forms" a, "" an, "and" the "are intended to mean" one "or" an "without the use of quantity prior to the element, but it is also intended to correspond to the meaning of" one or more, "" at least one, "and" one or more than one.

The words "comprising," "having," "including," or "containing" are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

The fertilizer compositions of the present invention may "comprise," "consist essentially of," or "consist of" the particular ingredients, components, compositions, etc. disclosed throughout this specification. With respect to the conjunction "consisting essentially of … …," in one non-limiting aspect, an essential and novel feature of the fertilizer granule compositions of the present invention is their ability to inhibit the degradation of heat sensitive components contained in the core granule.

Other objects, features and advantages of the present invention will become apparent from the following drawings, detailed description and examples. It should be understood, however, that the drawings, detailed description, and examples, while indicating specific embodiments of the present invention, are given by way of illustration only, and are not intended to be limiting. In addition, it is contemplated that variations and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features of any other embodiment. In other embodiments, additional features may be added to the specific embodiments described herein.

Drawings

Advantages of the present invention will become apparent to those skilled in the art from the following detailed description, taken in conjunction with the accompanying drawings. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings. The drawings may not be to scale.

Fig. 1 shows a cross-section of a fertilizer granule embodiment.

Fig. 2 depicts an embodiment of a method of producing a fertilizer granule.

Figure 3 shows the results of an experiment comparing the stability of NBTPT in four different fertilizer granule structures: (1) particles comprising NBTPT ("N") in the core (F51N); (2) particles comprising NBTPT in the core and DCD ("D") in the shell (F-152 ND); (3) particles comprising NBTPT in the shell (F-154N); (4) the core contained particles of both NBTPT and DCD (F-50 ND).

Detailed Description

The fertilizer granules described herein comprise two discrete portions: a core particle and a nitrogen-containing fertilizer composition in contact with the core particle. The granule comprises a urease inhibitor and a nitrification inhibitor which are kept separate by virtue of being located in two discrete portions of the granule. For example, in some embodiments, the urease inhibitor NBTPT is located only in the core granule, while the nitrification inhibitor is located only in the nitrogen-containing fertilizer composition, which in certain embodiments is also referred to as the "shell" portion of the fertilizer granule. These and other non-limiting aspects of the invention are discussed in further detail in the following sections.

A. Fertilizer granules

An exemplary cross-sectional view of an embodiment of a fertilizer granule is depicted in fig. 1. In the embodiment shown, fertilizer granule 10 may include a core granule 2 and a shell 4. The core particle 2 has a circular cross-section, but can be easily made in other shapes. The core particle 2 may comprise the urease inhibitor NBTPT and at least one binder. The core particle 2 may also comprise fillers, pH balancing agents and/or polymeric thickeners. In the embodiment shown, the shell 4 surrounding the core particle 2 is made of a solid urea-containing composition comprising the nitrification inhibitor DCD. In the embodiment shown, NBTPT and DCD are kept separate within the fertilizer granule 10 by placing them in different regions of the granule (NBTPT in the core granule and DCD in the shell).

It will be apparent to those of ordinary skill in the art that other configurations of fertilizer granules 10 are possible. For example, the core particle 2 may comprise a nitrification inhibitor, while the shell 4 may comprise a urease inhibitor. Alternatively, the core particle 2 may be made of a urea-comprising composition to which an inhibitor is added, the shell 4 consisting of a binder, a filler and an inhibitor. In some embodiments, it is preferred to include DCD in the urea-containing shell 4, since DCD can be added to molten urea during the manufacturing process without causing significant degradation of DCD, while NBTPT is susceptible to degradation under the same conditions. By placing NBTPT within the core particle 2, it can be protected from thermal degradation during the manufacturing process.

Although the fertilizer granules 10 shown in fig. 1 have a circular cross-section, various shapes are possible. For example, the fertilizer granules may be spherical, disc-shaped, ovoid, or elliptical. The fertilizer granules may also be of various sizes. In some embodiments, the fertilizer granules have a longest dimension of about 1mm to 8 mm.

The binders used in the fertilizer granules may be selected according to their suitability for the extrusion process for preparing the core granules. In some cases, the binder may receive a solvent, such as water. As used herein, "accepting a solvent" means that the solvent will affect the adhesive properties of the adhesive. Thus, as described herein, suitable solvents will affect the adhesive properties of the particular binder in the formulation, as well as other binders, fillers and excipients.

The core particles and fertilizer particles disclosed herein have desirable physical properties, such as desirable levels of attrition resistance, particle strength, pelletizability, hygroscopicity, particle shape, and size distribution, which are important properties for fertilizer core particles. Thus, the binder may be selected to optimize these properties.

A particular application of the embodiments disclosed herein is the stabilization of inhibitors, such as the stabilization of NBTPT and other fertilizer additives present in the core particle. Some fertilizer additives are unstable and are susceptible to degradation when exposed to high temperatures, pH changes (acidic or basic), and the like. In particular instances, the fertilizer core particles disclosed herein are embedded in or coated with a fertilizer composition, such as urea. In some cases, the shell comprising urea substantially surrounds at least a portion of the outer surface of the core particle.

In conventional fertilizer technology, various fertilizer additives are mixed with the fertilizer using an "all in one" process. In these cases, the fertilizer, fertilizer additives, excipients, and other ingredients are mixed together to form the fertilizer composition in the form of granules or pellets. In most cases, granulation is carried out at elevated temperatures to bring the fertilizer composition into a molten state. For example, the granulation temperature of molten urea is about 135 ℃ at about 35 atmospheres. Under these conditions, many fertilizer additives at least partially degrade. Traditionally, these stability problems have been addressed by using large excesses of fertilizer additives. Such processes, while in use, are not optimal and lead to problems with cost, efficacy, by-products, environmental waste, and greenhouse gases, among others.

The production of the core particles disclosed herein provides a solution to the instability of fertilizer additives at higher temperatures. The binder, pH stabilizer, and/or filler may be selected such that the resulting composition synergistically protects the fertilizer additive from high temperature degradation. As disclosed herein, the binder, pH stabilizer, filler, and polymeric thickener may be mixed with the fertilizer additive and extruded to form the core particle.

In some embodiments, no nitrogen fertilizer composition is present in the core particle. Thus, in this case only fertilizer additives, such as urease inhibitors or nitrification inhibitors (as well as binders, pH buffers and/or fillers) are present in the core particle.

Certain fertilizer additives are unstable to changes in the pH of the composition during preparation or after application to soil. For example, in the case of nitrogen-containing fertilizers, the soil environment will become acidic after application. Thus, p-acidThe pH sensitive fertilizer additive degrades and will not be able to achieve its full performance. The inclusion of large excesses of fertilizer additives to compensate for losses due to pH changes may not be successful because large excesses of fertilizer (as compared to fertilizer additives) may continue to change the pH of the soil environment. Also, some commercial products, e.g.

The fertilizer additive is added to the fertilizer composition using an organic solvent, such as NMP. Such use is undesirable and avoided in the production of certain embodiments of the fertilizer granules described herein.

In some embodiments disclosed herein, the core particle is embedded in a nitrogen-containing fertilizer composition, including a urea-containing composition. For example, in some embodiments, the shell comprising the fertilizer composition at least partially surrounds the outer surface of the fertilizer core particle. In some of these embodiments, the shell comprises a nitrogen fertilizer-containing composition, such as urea. In some cases, two or more than two core particles may be embedded in the urea matrix.

B. Urease inhibitors and nitrification inhibitors

Urea is one of the most widely used fertilizers due to its high nitrogen content (46.6%). Various urease inhibitors and nitrification inhibitors have been developed to improve the efficiency of urea fertilizers, but their use can be challenging due to stability issues in the soil under various conditions (e.g., pH, temperature, precipitation, etc.). For example, NBTPT is known to be a good inhibitor of urease, but is unstable at acidic pH. NBTPT also decomposes when exposed to high temperatures, such as the temperature at which urea melts (about 135 ℃ to 140 ℃).

To overcome these problems, embodiments of fertilizer granules are provided wherein the fertilizer granules comprise a core granule coated with an outer coating of urea that first contacts the soil, thereby protecting the active ingredient in the core granule so that it will be gradually released. The fertilizer core particle may comprise both a binder and a pH buffering agent. pH buffers (e.g. CaCO)₃Available in the form of chalk powder) is a compound which neutralizes urineThe acidity caused by hydrolysis of the element thereby prevents degradation of the active agent (e.g., NBTPT) when placed in soil at acidic pH. Thus, the pH buffer may increase the efficacy of the active agent, such as NBTPT, and also maintain the pH of the soil. The fertilizer granule also has the advantage of keeping the urease inhibitor and nitrification inhibitor in separate areas of the fertilizer granule, which prevents any degradation or other detrimental effects resulting from the combination of different inhibitors.

The binder in the fertilizer core particle protects the active ingredient (e.g., NBTPT) from exposure to high temperatures during granulation, thereby preventing decomposition of the NBTPT during granulation. For example, a core containing plaster of paris (PoP) can be effective in preventing degradation of NBTPT during granulation. In such formulations, all active ingredients are protected by the PoP inside the core.

Other inhibitors besides NBTPT and DCD may also be included in the fertilizer granules described herein, including but not limited to 3, 4-dimethylpyrazole phosphate (DMPP), Thiourea (TU), Phenyl Phosphorodiamidite (PPDA), 2-chloro-6- (trichloromethyl) -pyridine (triclopyr), 5-ethoxy-3-trichloromethyl-1, 2, 4-thiadiazole (cloxazole), 2-amino-4-chloro-6-methyl-pyrimidine (AM), 2-Mercaptobenzothiazole (MBT), or 2-Sulfoaminoimidazole (ST), or combinations thereof.

In addition to urea, other fertilizer materials may be included in the fertilizer granule. Other fertilizers may be selected based on the particular needs of certain types of soil, climate or other growing conditions to maximize the efficacy of the fertilizer granules in enhancing plant growth and crop yield. Other additives may also be included in the fertilizer granule including, but not limited to, micronutrients, primary nutrients, and secondary nutrients. Micronutrients are phytologically acceptable forms of inorganic or organometallic compounds such as boron, copper, iron, chloride, manganese, molybdenum, nickel or zinc. The primary nutrients are substances that can deliver nitrogen, phosphorus and/or potassium to plants. The primary nitrogen-containing nutrient may include urea, ammonium nitrate, ammonium sulfate, diammonium phosphate, monoammonium phosphate, urea formaldehyde, or a combination thereof. Secondary nutrients are substances that can deliver calcium, magnesium and/or sulfur to plants. The secondary nutrient may include lime, gypsum, calcium superphosphate, or a combination thereof.

C. Adhesive agent

The fertilizer granules described herein may comprise a binder, which is a substance used to bind the components of the mixture together by adhesive and/or cohesive forces. The core particle may comprise 10 to 99 wt% of the binder. The amount and type of binder may be selected based on the desired final properties of the core particle. The binder may be selected such that an extrusion process may be used during the production of the core particle. It will be appreciated that for certain binders, such as plaster of paris and bleached wheat flour, a certain amount of water (moisture) is required to make the core extrudable. Any free moisture present in the core during extrusion is typically removed after extrusion. However, there may be a residual free moisture content in the core particle, typically below 4 wt%, for example below 0.5 wt%.

In one aspect, the binder can comprise a phosphate, a polyphosphate, a biodegradable polymer or a wax, or a combination thereof. Suitable waxes include, but are not limited to, vegetable waxes, high melt waxes, ethylene bis (stearamide) waxes, paraffin waxes, polyethylene based waxes, and olefin waxes. Suitable phosphates include, but are not limited to, diammonium phosphate and monoammonium phosphate. Suitable polyphosphates may include, but are not limited to ammonium polyphosphate. Suitable biodegradable polymers include, but are not limited to, polyacrylamide, polyacrylic acid, polyacrylonitrile, biodegradable polylactic acid, and other biodegradable polymeric materials, such as polylactic acid, poly (3-hydroxypropionic acid), polyvinyl alcohol, poly-epsilon-caprolactone, poly-L-lactide, polybutylene succinate, and biodegradable starch-based polymers.

In another aspect, the binder may comprise plaster of paris, flour, starch, gluten, kaolin, bentonite, colloidal silica, or a combination thereof. Suitable flours include, but are not limited to, rice flour, wheat flour, and bleached wheat flour. Suitable starches may include, but are not limited to, dextrin-modified starches.

pH buffers

The core particle may contain one or more than one pH buffering agent to help counteract the tendency of the urea fertilizer to acidify the soil. Examples of suitable pH buffers include, but are not limited toNot limited to, CaCO₃、MgO、KH₂PO₄、NaHCO₃Chalk, aluminium, magnesium hydroxide, aluminium hydroxide/magnesium hydroxide coprecipitate, aluminium hydroxide/sodium bicarbonate coprecipitate, calcium acetate, calcium bicarbonate, calcium borate, calcium carbonate, calcium bicarbonate, calcium citrate, calcium gluconate, calcium hydroxide, disodium hydrogen phosphate, dipotassium hydrogen phosphate, disodium hydrogen phosphate, magnesium acetate, magnesium borate, magnesium bicarbonate, magnesium carbonate, magnesium hydroxide, magnesium lactate, magnesium oxide, magnesium phosphate, magnesium silicate, magnesium succinate, magnesium tartrate, potassium acetate, potassium carbonate, potassium bicarbonate, potassium borate, potassium citrate, potassium metaphosphate, potassium phthalate, potassium phosphate, potassium polyphosphate, potassium pyrophosphate, potassium succinate, potassium tartrate, sodium acetate, sodium bicarbonate, sodium borate, sodium carbonate, sodium citrate, sodium gluconate, sodium hydrogen phosphate, sodium hydroxide, sodium lactate, sodium phthalate, Sodium phosphate, sodium polyphosphate, sodium pyrophosphate, sodium tartrate, sodium tripolyphosphate, synthetic hydrotalcite, tetrapotassium pyrophosphate, tetrasodium pyrophosphate, tripotassium phosphate, trisodium phosphate, tromethamine, and combinations thereof.

E. Filler material

The core particle in the fertilizer particle may contain a filler, which is a material that may improve the physical properties of the core particle (e.g., compressive strength, homogeneity, and extrusion characteristics) or alter the release kinetics of inhibitors or micronutrients from the core particle. The filler combined with the binder may be selected to enhance the physical and release properties of the core particle. The filler may comprise, for example, silica, distillers dried grains with solubles (DDGS), rice bran, or other biological material, or a combination thereof.

F. Nitrogenous fertilizer composition

In one aspect, the fertilizer granule may comprise an outer layer or shell comprising a nitrogen fertilizer (e.g., urea) or a combination of urea and other nitrogen fertilizers. Suitable other nitrogen fertilizers include, but are not limited to, ammonium nitrate, ammonium sulfate, DAP, MAP, urea formaldehyde, ammonium chloride, and potassium nitrate. The shell containing urea can be fertilized (fat) onto the core particle by spraying molten urea onto the core particle during granulation.

G. Composition comprising a metal oxide and a metal oxide

The fertilizer granules described herein may be included in a composition for application to soil. In addition to the fertilizer granules, the composition may include other fertilizer compounds, micronutrients, primary nutrients, secondary nutrients, pesticides, herbicides, fungicides, and combinations thereof.

The fertilizer granules described herein may also be included in a blend composition containing other fertilizer granules. Other fertilizer granules may be granules of urea, mono super phosphate (SSP), Tri Super Phosphate (TSP), ammonium sulphate, etc. In some cases, the other fertilizer particles include a core. In these cases, the core may comprise urea, a urease inhibitor, a nitrification inhibitor, and at least one of a binder, a filler, a pH buffer, and/or a polymeric thickener. The shell may contain fertilizer and/or fertilizer active disposed around the cores. In some cases, the fertilizer may be urea and the fertilizer active may be at least one of a urease inhibitor or a nitrification inhibitor. In some of these embodiments, the shell comprises an inclusin and a nitrification inhibitor. In some other embodiments, the shell comprises urea and a urease inhibitor.

H. Method for producing fertilizer granules

In some embodiments, the core particle is prepared by extruding a composition comprising the urease inhibitor, the binder, and optionally other suitable materials such as fillers, pH balancing agents, or other additives. The composition may be formed by mixing the ingredients in dry form, adding any solvent if necessary and further mixing to produce an extrudable composition. If the binder is plaster, flour, starch or gluten, a solvent (e.g., water) may be required to prepare the extrudable composition, but if the binder comprises a wax, it may not be required. The extrusion may be performed using suitable extruder equipment known in the art, and may be performed at a temperature of 0 ℃ to 150 ℃ and a screw speed of 1rpm to 500rpm, wherein the extruder may comprise a multi-feed machine comprising an extrusion assembly, which may include a main drive, shaft, screw, barrel, and/or die. In some embodiments, the binder may be plaster of paris and the extrusion is performed at a temperature of about 15 ℃ to 50 ℃. In some embodiments, the extrusion process may include cutting the extrudate to form core particles having a cylindrical shape and a diameter and length of between about 0.5 and 2.0 mm. The method may also include a drying step to remove solvent that may have been added to make the composition extrudable. The cylindrical core particle may be spheronized to produce a core particle having a substantially spherical shape.

The core particle may be fertilized with a shell comprising a urea-comprising composition to form a fertilizer particle. The fattening process may comprise spraying the molten urea-comprising composition onto the core particles, for example in a granulation apparatus known in the art. When the molten urea-comprising composition is sprayed onto the core particles, it cools and solidifies, thereby forming fertilizer granules. The resulting fertilizer granules can be of various sizes. In some embodiments, the fertilizer particles are about 1mm to 8mm in size.

Fig. 2 illustrates an embodiment of a method by which fertilizer granules 10 may be produced. To prepare the core particle 2, the core particle ingredients, which may include binders, fillers, pH balancing agents, polymeric thickeners, and NBTPT, as well as other suitable ingredients, are placed into the hopper of the extruder 6. The extruder 6 pushes the mixed core particle composition through the die 8 during the extrusion process 12. In the extrusion process 12, the extrudate is cut into pieces by a cutting tool (not shown) connected to the die 8 to form core particles 2 (not drawn to scale), which may be further processed (not shown) to dry and form spheres, if desired. The core particles are then added to the granulator 14. The molten urea may also include DCD, which is fed to the granulator via line 16. Within the granulator 14, the molten urea is sprayed onto the surface of the core particles 2, where it cools and solidifies in a process known as fattening 18. After fattening 18, the fertilizer granule 10 has a core granule 2 and a solid urea-containing shell.

After final treatment, most of the fertilizer granules 10 are within specification. However, some fertilizer granules are too large or too small. These rejected granules are separated, comminuted, and the powdered material is then redirected into a granulator. The recovered powdery material is granulated and then molten urea is sprayed onto the surface of the granulated material. In some embodiments, the granules including the recycled composition may be mixed with fertilizer granules 10. These compositions may comprise from 20% to 50% by weight of the particles comprising the recycled composition.

I. Application method of fertilizer granules

The fertilizer granules described herein are useful in methods of increasing the amount of nitrogen in soil and enhancing plant growth. Such methods may include applying to the soil an effective amount of a composition comprising fertilizer granules. The method may include increasing the growth and yield of crops such as rice, wheat, corn, barley, oats, and soybean.

The effectiveness of a composition comprising the fertilizer particles described herein can be determined by measuring the nitrogen content in the soil at various times after the fertilizer composition is applied to the soil. It is understood that different soils have different characteristics which affect the stability of nitrogen in the soil. The effectiveness of the fertilizer composition can also be directly compared to other fertilizer compositions by side-by-side comparison in the same soil under the same conditions. Compositions comprising fertilizer particles as described herein may be directly mixed with, for example

Or

Compare with the fertilizer.Sold by Koch Fertilizer, LLC (u.s.a.), is a liquid formulation containing NBTPT, which is based on NMP as the main solvent and contains other additives, and is usually sprinkled onto urea granules at the farm site. Therefore, it requires an additional step and incorporates NMP, a toxic solvent, before it can be used by farmers. A huge odor occurs during use.Sold by Koch Fertilizer, LLC,is a urea formulation containing NBTPT and DCD prepared by adding both inhibitors to the urea melt during granulation.