The present invention relates to a mixture comprising a nitrogen-containing fertilizer, a nitrification inhibitor and a composition comprising primary and/or secondary alkyl and/or alkylene monoamines, a method of obtaining such a mixture, as well as the use of a composition comprising primary and/or secondary alkyl and/or alkylene monoamines for the anti-caking or dust-preventing treatment of a fertilizer mixture comprising a nitrogen-containing fertilizer and a nitrification inhibitor.

Nitrogen is an essential element for plant growth and reproduction. About 25% of the plant- available nitrogen in soils (ammonium and nitrate) originates from decomposition processes (mineralization) of organic nitrogen compounds such as humus, plant and animal residues and organic fertilizers. Approximately 5% derive from rainfall. On a global basis, the biggest part (70%), however, are supplied to the plant by inorganic nitrogen fertilizers. Without the use of nitrogen fertilizers, the earth would not be able to support its current population.

Soil microorganisms convert organic nitrogen to ammonium (NfV) which is subsequently oxidized to nitrate (NO3 ) in a process known as nitrification. Albeit very important for agriculture, nitrate is highly mobile in the soil and may be readily lost from soils by leaching to ground water. Nitrogen is further lost by microbiological denitrification to gaseous forms of nitrogen. As a result of the various losses, approximately 50% of the applied nitrogen is lost during the year following fertilizer addition (cf. Nelson and Huber; Nitrification inhibitors for corn production (2001 ), National Corn Handbook, Iowa State University).

Nitrification inhibitors such as pyrazole compounds can be used in order to reduce nitrification and consequently increase fertilization efficacy and decrease nitrogen levels in the groundwater and surface waters and nitrogen oxide levels in the atmosphere. A problem associated with the use of pyrazole compounds is their volatility, which results in losses of the nitrification inhibitor during storage. In order to address this problem, addition salts of pyrazoles as well as pyrazole derivatives with hydrophilic groups have been described in the prior art.

EP 1 120388 B1 and EP 0917526 B1 discloses the use of a phosphoric acid addition salt or a poly acid addition salt of 3,4-dimethyl pyrazole as nitrification inhibitor.

WO 96/24566 describes methods of producing low-volatile pyrazole derivatives with hydrophilic groups such as 2-(3-methyl-1 H-pyrazole-1 -yl) succinic acid to be used as nitrification inhibitors.

WO 201 1/032904 and WO 2013/121384 describe 2-(3,4-dimethyl-1 H-pyrazole-1 -yl) succinic acid as nitrification inhibitor.

It is known that most fertilizers, for example but not limited to ammonium nitrate-based, urea- based NPK fertilizers, have a certain degree of tendency to form agglomerates during the storage process. This phenomenon, also referred to as caking, is described for example in D.W. Rutland,“Fertilizer caking: mechanisms, influential factors, and methods of prevention”, Fertilizer Research 30: 99-1 14, 1991.

DE 1592572 discloses the use of polyethylene wax as coating agent for granulated or crystalline fertilizers to prevent the caking of the fertilizers.

EP 0908433 A1 discloses compositions for the anticaking and dust-preventing treatment of ag ricultural ammonium nitrates composed a mixture of primary and secondary alkyl and/or al- kylene monoamines, of aluminium stearate, of fatty alcohol.

Therefore, it was an object of the present invention to provide a specific mixture comprising fertilizer and nitrification inhibitors in which the formation of agglomerates (caking) can be prevented during the storage process. This mixture is referred to as mixture (Q) in the following. Furthermore, it was an object of the present invention to provide a mixture comprising fertilizer and nitrification inhibitors, which has at least one of the following features:

(i) enabling simple handling and application of the mixture (Q),

(ii) improved physical and/or chemical and/or other stability of the mixture (Q) during the storage process, e.g. over 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20 or more weeks,

(iii) be easily and safely packaged, transported and shipped, even in large quantities,

(iv) providing a mixture (Q) which can be easily and safely packaged, transported and shipped, even in large quantities,

(v) providing a mixture (Q) which can be easily and safely handled and applied for soil treatment, even in large quantities, and/or

(vi) proving a ready-to-use mixture (Q),

(vii) reducing the emission of nitrous oxide from soils, and/or

(viii) reducing the ammonia emission from soils, and/or

(ix) reducing nitrate leaching, and/or

(x) toxicologically unobjectionable.

The preferred objects of the present invention are (i), (ii), (iii), (iv), (v), (vi), and/or (x), the more preferred objects of the present invention are (i), (ii), (ii), (iv), the most preferred objects of the present invention are (i), (ii), the particularly preferred object of the present invention is (ii).

In view of the above objects, the present invention relates to a mixture comprising

a) at least one nitrogen-containing fertilizer (A), and

b) at least one nitrification inhibitor (B) selected from the group consisting of 3,4-dimethyl- 1 H-pyrazole (DMP), 3,4-dimethyl-1 /-/-pyrazole phosphate (DMPP), 2-(3,4-dimethyl-1 /-/- pyrazol-1 -yl)succinic acid (DMPSA1 ), 2-(4,5-dimethyl-1 H-pyrazol-1-yl)succinic acid (DMPSA2), and salts thereof, and c) a composition (C) comprising primary and/or secondary alkyl and/or alkylene monoamines.

Furthermore, the present invention relates to a method of obtaining the above-mentioned mixture, wherein the fertilizer mixture comprising

a) at least one nitrogen-containing fertilizer (A), and

b) at least one nitrification inhibitor (B) selected from the group consisting of 3,4-dimethyl- 1 H-pyrazole (DMP), 3,4-dimethyl-1 /-/-pyrazole phosphate (DMPP), 2-(3,4-dimethyl-1 /-/- pyrazol-1 -yl)succinic acid (DMPSA1 ), 2-(4,5-dimethyl-1 H-pyrazol-1-yl)succinic acid (DMPSA2), and salts thereof,

is treated with a composition (C) comprising primary and/or secondary alkyl and/or alkylene monoamines

in the proportion of 0.1 kg per ton to 5 kg per ton.

Furthermore, the present invention relates to the use of a composition (C) comprising primary and/or secondary alkyl and/or alkylene monoamines for the anti-caking or dust-preventing treat ment of a fertilizer mixture comprising

a) at least one nitrogen-containing fertilizer (A), and

b) at least one nitrification inhibitor (B) selected from the group consisting of 3,4-dime- thyM H-pyrazole (DMP), 3,4-dimethyl-1 /-/-pyrazole phosphate (DMPP), 2-(3,4-dime- thyl-1 /-/-pyrazol-1 -yl)succinic acid (DMPSA1 ), 2-(4,5-dimethyl-1 /-/-pyrazol-1 -yl)succinic acid (DMPSA2), and salts thereof.

In the present patent application, 3,4-dimethyl-1 H-pyrazole is referred to as“DMP”, 3,4-dime- thyl-1 /-/-pyrazole phosphate is referred to as“DMPP”, 2-(3,4-dimethyl-1 H-pyrazol-1 -yl)succinic acid is referred to as“DMPSA1”, 2-(4,5-dimethyl-1 H-pyrazol-1 -yl)succinic acid is referred to as “DMPSA2”,“DMPSA1” and/or“DMPSA2” is referred to as“DMPSA”, weight percent is referred to as“wt%”.“Per ton” is referred to as“per ton of nitrogen-containing fertilizer (A)”, if not specified otherwise.

In a preferred embodiment, the nitrogen-containing fertilizer (A) is an ammonium-containing fertilizer.

In another preferred embodiment, the nitrogen-containing fertilizer (A) is selected from the group consisting of ammonium nitrate, calcium ammonium nitrate, ammonium sulfate, ammonium chloride, ammonium carbonate, ammonium sulfate nitrate, diammonium phosphate, monoammonium phosphate, ammonium thiosulfate, urea, and NPK fertilizer. In another preferred embodiment, the nitrogen-containing fertilizer (A) is ammonium sulfate, or ammonium sulfate nitrate. In another preferred embodiment, the nitrogen-containing fertilizer (A) is ammonium sulfate nitrate.

In another preferred embodiment, the nitrification inhibitor (B) is 3,4-dimethyl-1 H-pyrazole phosphate (DMPP). In another preferred embodiment, the nitrification inhibitor (B) is 3,4-dimethyl-1 - - pyrazole (DMP). In another preferred embodiment, the nitrification inhibitor (B) 2-(3, 4-dimethyl- 1 H-pyrazol-1 -yl)succinic acid (DMPSA1 ), and/or 2-(4,5-dimethyl-1 H-pyrazol-1 -yl)succinic acid (DMPSA2), and/or salts thereof, preferably ammonium or potassium salts of DMPSA1 and/or DMPSA2.

The nitrification inhibitor can be present in any form, for example in solid form, in crystalline form, powder form, liquid form, formulated form (formulation), or liquid solution form.

The composition (C) comprises 1 to 40 wt.-% of an amine mixture of primary and/or secondary alkyl and/or alkylene monoamines based on the total weight of composition (C).

In a preferred embodiment, the amount of the amine mixture of primary and/or secondary alkyl and/or alkylene monoamines within the composition (C) is preferably not less than 2 wt.-%, more preferably not less than 4 wt.-%, most preferably not less than 6 wt.-%, particularly preferably not less than 8 wt.-%, particularly more preferably not less than 10 wt.-%, particularly most preferably not less than 12 wt.-%, particularly not less than 14 wt.-% based on the total weight of the composition (C). In another preferred embodiment, the amount of the amine mixture of primary and/or secondary alkyl and/or alkylene monoamines within the composition (C) is preferably not more than 37 wt.-%, more preferably not more than 34 wt.-%, most preferably not more than 31 wt.-%, particularly preferably not more than 28 wt.-%, particularly more preferably not more than 25 wt.-%, particularly most preferably not more than 22 wt.-%, particularly not more than 19 wt.-% based on the total weight of the composition (C).

In a preferred embodiment, the amount of the amine mixture of primary and/or secondary alkyl and/or alkylene monoamines within the composition (C) is from 10wt.% to 25 wt.% based on the total weight of the composition (C).

In a preferred embodiment, the composition (C) comprises 1 to 40 wt.-% of an amine mixture of primary and/or secondary alkyl and/or alkylene monoamines based on the total weight of composition (C), wherein the ratio of secondary alkyl and/or alkylene monoamines is from 25 to 75 wt.- %, preferably from 30 to 70 wt.-%, more preferably from 35 to 65 wt.-%, most preferably from 40 to 60 wt.-%, particularly preferably from 45 to 55 wt.-% based on the total weight of alkyl and/or alkylene monoamines.

In another preferred embodiment, the composition (C) comprises primary and/or secondary alkyl and/or alkylene monoamines which are amines having alkyl and/or alkylene chains containing a number of carbons from 6 to 40, more preferably from 8 to 35, most preferably from 10 to 30, particularly preferably from 12 to 25, particularly from 14 to 20.

In another preferred embodiment, the composition (C) comprises hydrogenated tallow amines as primary and/or secondary alkyl and/or alkylene monoamines.

In another preferred embodiment, the composition (C) comprises 1 -aminohexadecane, 1-ami- noheptadecane, 1-aminooctadecane (stearyl amine), and/or A/-hexadecyl-/V-octadecylamine and/or their corresponding ammonium (NfV) forms as primary and/or secondary alkyl and/or alkylene monoamines.

In the present patent application, the corresponding ammonium (NIV) forms of the amines are also included in the term“primary and/or secondary alkyl and/or alkylene monoamines”.

In one preferred embodiment, the composition (C) optionally further comprises 1 to 40 wt.-% of fatty acids based on the total weight of composition (C).

In a preferred embodiment, the amount of the fatty acid within the composition (C) is preferably not less than 2 wt.-%, more preferably not less than 4 wt.-%, most preferably not less than 6 wt.-%, particularly preferably not less than 8 wt.-%, particularly more preferably not less than 10 wt.-%, particularly most preferably not less than 12 wt.-%, particularly not less than 14 wt.-% based on the total weight of the composition (C). In another preferred embodiment, the amount of the fatty acid within the composition (C) is preferably not more than 37 wt.-%, more preferably not more than 34 wt.-%, most preferably not more than 31 wt.-%, particularly preferably not more than 28 wt.-%, particularly more preferably not more than 25 wt.-%, particularly most pref erably not more than 22 wt.-%, particularly not more than 19 wt.-% based on the total weight of the composition (C).

In a preferred embodiment, the amount of the fatty acid within the composition (C) is from 10wt.% to 25 wt.% based on the total weight of the composition (C).

In another preferred embodiment, the composition (C) optionally further fatty acids having alkyl and/or alkylene chains containing a number of carbons from 6 to 40, more preferably from 8 to 35, most preferably from 10 to 30, particularly preferably from 12 to 25, particularly from 14 to 20, for instance from 14 to 18, for example from 16 to 18.

In another preferred embodiment, the composition (C) comprises tetradecanoic acid (myristic acid), pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), and/or octadecanoic acid (stearic acid), and/or their corresponding carboxylate (COO ) forms as fatty acids.

In the present patent application, the corresponding carboxylate (COO ) forms of the acids are also included in the term“fatty acid”.

In another preferred embodiment, the composition (C) comprises a mixture of

(Ci) primary and/or secondary alkyl and/or alkylene monoamines (referred to as“(C1 )” in the following), and

(Cii) fatty acids (refered to as“(C2)” in the following).

In another preferred embodiment, the composition (C) comprises a mixture of

(Ci) primary and/or secondary alkyl and/or alkylene monoamines which are amines having alkyl and/or alkylene chains containing a number of carbons from 6 to 40, more preferably from 8 to 35, most preferably from 10 to 30, particularly preferably from 12 to 25, particularly from 14 to 20, and

(Cii) fatty acids having alkyl and/or alkylene chains containing a number of carbons from 6 to 40, more preferably from 8 to 35, most preferably from 10 to 30, particularly preferably from 12 to 25, particularly from 14 to 20, for instance from 14 to 18, for example from 16 to 18.

In another preferred embodiment, the composition (C) comprises a mixture of

(Ci) 1-aminohexadecane, 1 -aminoheptadecane, 1-aminooctadecane (stearyl amine), and/or N- hexadecyl-/V-octadecylamine, and

(Cii) tetradecanoic acid (myristic acid), pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), and/or octadecanoic acid (stearic acid).

The mixture of

(Ci) primary and/or secondary alkyl and/or alkylene monoamines, and

(Cii) fatty acids

can be either a reaction mixture, a physical mixture, or a salt.

In another preferred embodiment, the composition (C) comprises a mixture of (C1 ) and (C2), wherein the molar ratio of (C1 ) to (C2) is preferably in the range of 100:1 to 1 : 100, more preferably in the range of 40:1 to 1 :40, most preferably in the range of 20:1 to 1 :20, particularly preferably in the range of 10:1 to 1 :10, particularly more preferably in the range of 5:1 to 1 :5, particularly most preferably in the range of 3:1 to 1 :3, particularly in the range of 2:1 to 1 :2, for instance preferably in the range of 1.5:1 to 1 :1.5, for instance more preferably in the range of 1.2:1 to 1 :1.2, for example 1 :1 .

In another preferred embodiment, the composition (C) comprises a mixture of (C1 ) and (C2), wherein the weight ratio of (C1 ) to (C2) is preferably in the range of 100:1 to 1 : 100, more preferably in the range of 40:1 to 1 :40, most preferably in the range of 20:1 to 1 :20, particularly preferably in the range of 10:1 to 1 :10, particularly more preferably in the range of 5:1 to 1 :5, particularly most preferably in the range of 3:1 to 1 :3, particularly in the range of 2:1 to 1 :2, for instance preferably in the range of 1.5:1 to 1 :1.5, for instance more preferably in the range of 1.2:1 to 1 :1.2, for example 1 :1 .

In another preferred embodiment, the composition (C) may optionally further comprise aluminium stearate, preferably 1 to 20 wt.-% of aluminium stearate, more preferably 1 to 15 wt.-% of aluminium stearate, most preferably 2 to 8 wt.-% of aluminium stearate, based on the total weight of composition (C).

In another preferred embodiment, the composition (C) may optionally further comprise fatty alcohol, preferably 1 to 20 wt.-% of of fatty alcohol, more preferably 1 to 15 wt.-% of fatty alcohol, most preferably 2 to 8 wt.-% of fatty alcohol based on the total weight of composition (C).

In another preferred embodiment, the composition (C) may optionally further comprise as fatty alcohol an alcohol having an alkyl and/or alkylene chain containing from 10 to 24 carbon atoms, for example octadecyl alcohol (stearyl alcohol), arachidic alcohol or behenic alcohol. In another preferred embodiment, the composition (C) may optionally further comprise as fatty alcohol octa decyl alcohol. In another preferred embodiment, the composition (C) may optionally further comprises 2 to 8 wt.-% fatty alcohol based on the total weight of composition (C), wherein the fatty alcohol is octadecyl alcohol.

The remaining part of the compositon (C) which is neither a alkyl and/or alkylene monoamines, nor aluminium stearate, nor a fatty alcohol, can be normal fillers, oily or waxy ingredients well- known to the persons skilled in the art, for example waxes such as paraffin or petroleum waxes.

In another preferred embodiment, the composition (C) may optionally further comprise a wax, preferably paraffin or petroleum wax, more preferably paraffin wax.

For example, the composition (C) can be prepared very simply by dissolving or dispersing their various components in an oily ingredient, proceeding with heat to 80° C. and stirring until a homogeneous composition is obtained. If these compositions are cold, they are in general in a pasty appearance. They can be applied in the molten state, by spraying at temperatures around 80 ° C., to the fertilizer to be treated which has been previously loaded at room temperature in a rotary drum. The spraying is preferably carried out by an air spraying system. The residence time of the fertilizer in the coating drum is extended for a further minute for better homogenization of the coating. The quantities deposited are generally between 0.1 kg / 1 and 5 kg / 1 of fertilizer. These are conditions which are known to persons skilled in the art.

According to one embodiment of the present invention, the above-specified mixture according to the present invention can be obtained in a way wherein the fertilizer mixture comprising

a) at least one nitrogen-containing fertilizer (A), and

b) at least one nitrification inhibitor (B) selected from the group consisting of 3,4-dimethyl- 1 H-pyrazole (DMP), 3,4-dimethyl-1 /-/-pyrazole phosphate (DMPP), 2-(3,4-dimethyl-1 /-/- pyrazol-1 -yl)succinic acid (DMPSA1 ), 2-(4,5-dimethyl-1 H-pyrazol-1-yl)succinic acid (DMPSA2), and salts thereof,

is treated with a composition (C) comprising primary and/or secondary alkyl and/or alkylene monoamines

in the proportion of 0.1 kg per ton to 5 kg per ton, preferably in the proportion of 0.5 kg per ton to 4 kg per ton, more preferably in the proportion of 1.0 kg per ton to 3.0 kg per ton.

According to another embodiment of the present invention, the above-specified mixture according to the present invention can be obtained in a way wherein

(i) the at least one nitrogen-containing fertilizer (A) is first treated with the at least one nitrification inhibitor (B) selected from the group consisting of 3,4-dimethyl-1 /-/-pyrazole (DMP), 3,4-dimethyl-1 /-/-pyrazole phosphate (DMPP), 2-(3,4-dimethyl-1 /-/-pyrazol-1- yl)succinic acid (DMPSA1 ), 2-(4,5-dimethyl-1 H-pyrazol-1 -yl)succinic acid (DMPSA2), and salts thereof, and (ii) the mixture obtained in step (i) is then treated with a composition (C) comprising primary and/or secondary alkyl and/or alkylene monoamines in the proportion of 0.1 kg per ton to 5 kg per ton, preferably in the proportion of 0,5 kg per ton to 4 kg per ton, more preferably in the proportion of 1.0 kg per ton to 3.0 kg per ton.

According to another embodiment of the present invention, the above-specified mixture according to the present invention can be obtained in a way wherein

(i) the at least one nitrogen-containing fertilizer (A) is first treated with a composition (C) comprising primary and/or secondary alkyl and/or alkylene monoamines in the pro portion of 0.1 kg per ton to 5 kg per ton, preferably in the proportion of 0,5 kg per ton to 4 kg per ton, more preferably in the proportion of 1.0 kg per ton to 3.0 kg per ton.

(ii) the mixture obtained in step (i) is then treated with the at least one nitrification inhibitor

(B) selected from the group consisting of 3,4-dimethyl-1 /-/-pyrazole (DMP), 3,4-dime- thyl-1 H-pyrazole phosphate (DMPP), 2-(3,4-dimethyl-1 /-/-pyrazol-1-yl)succinic acid (DMPSA1 ), 2-(4,5-dimethyl-1 H-pyrazol-1 -yl)succinic acid (DMPSA2), and salts thereof.

According to another embodiment of the present invention, the above-specified mixture according to the present invention can be obtained in a way wherein

(i) the at least one nitrification inhibitor (B) selected from the group consisting of 3,4-dime- thyl-1 H-pyrazole (DMP), 3,4-dimethyl-1 H-pyrazole phosphate (DMPP), 2-(3,4-dime- thyl-1 H-pyrazol-1 -yl)succinic acid (DMPSA1 ), 2-(4,5-dimethyl-1 H-pyrazol-1 -yl)suc- cinic acid (DMPSA2), and salts thereof (A) is first mixed or treated with a composition (C) comprising primary and/or secondary alkyl and/or alkylene monoamines,

(ii) the at least one nitrogen-containing fertilizer (A) is then treated with the mixture ob tained in step (i) in the proportion of 0.1 kg of the mixture [obtained in step (i) ] per ton (of fertilizer) to 5 kg per ton, preferably in the proportion of 0.5 kg per ton to 4 kg per ton, more preferably in the proportion of 1.0 kg per ton to 3.0 kg per ton.

In general, The term "fertilizers" is to be understood as chemical compounds applied to promote plant and fruit growth. Fertilizers are typically applied either through the soil (for uptake by plant roots), through soil substituents (also for uptake by plant roots), or by foliar feeding (for uptake through leaves). The term also includes mixtures of one or more different types of fertilizers as mentioned below.

The term "fertilizers" can be subdivided into several categories including: a) organic fertilizers (composed of plant/animal matter), b) inorganic fertilizers (composed of chemicals and minerals) and c) urea-containing fertilizers.

Organic fertilizers include manure, e.g. liquid manure, semi-liquid manure, biogas manure, stable manure or straw manure, slurry, liquid dungwater, sewage sludge, worm castings, peat, seaweed, compost, sewage, and guano. Green manure crops (cover crops) are also regularly grown to add nutrients (especially nitrogen) to the soil. Manufactured organic fertilizers include e.g. compost, blood meal, bone meal and seaweed extracts. Further examples are enzyme di- gested proteins, fish meal, and feather meal. The decomposing crop residue from prior years is another source of fertility.

Inorganic fertilizers are usually manufactured through chemical processes (such as e.g. the Ha- ber-Bosch process), also using naturally occurring deposits, while chemically altering them (e.g. concentrated triple superphosphate). Naturally occurring inorganic fertilizers include Chilean sodium nitrate, mine rock phosphate, limestone, sulfate of potash, muriate of potash, and raw potash fertilizers.

Typical solid fertilizers are in a crystalline, prilled or granulated form. Typical nitrogen containing inorganic fertilizers are ammonium nitrate, calcium ammonium nitrate, ammonium sulfate, ammonium sulfate nitrate, calcium nitrate, diammonium phosphate, monoammonium phosphate, ammonium thio sulfate and calcium cyanamide.

The inorganic fertilizer may be an NPK fertilizer. "NPK fertilizers" are inorganic fertilizers formulated in appropriate concentrations and combinations comprising the three main nutrients nitro gen (N), phosphorus (P) and potassium (K) as well as typically S, Mg, Ca, and trace elements. "NK fertilizers" comprise the two main nutrients nitrogen (N) and potassium (K) as well as typically S, Mg, Ca, and trace elements. "NP fertilizers" comprise the two main nutrients nitrogen (N) and phosphorus (P) as well as typically S, Mg, Ca, and trace elements.

Urea-containing fertilizer may, in specific embodiments, be formaldehyde urea, UAN, urea sulfur, stabilized urea, urea based NPK-fertilizers, or urea ammonium sulfate. Also envisaged is the use of urea as fertilizer. In case urea-containing fertilizers or urea are used or provided, it is particularly preferred that urease inhibitors as defined herein above may be added or addition ally be present, or be used at the same time or in connection with the urea-containing fertilizers.

Fertilizers may be provided in any suitable form, e.g. as coated or uncoated granules, in liquid or semi-liquid form, as sprayable fertilizer, or via fertigation etc.

Coated fertilizers may be provided with a wide range of materials. Coatings may, for example, be applied to granular or prilled nitrogen (N) fertilizer or to multi-nutrient fertilizers. Typically, urea is used as base material for most coated fertilizers. The present invention, however, also envisages the use of other base materials for coated fertilizers, any one of the fertilizer materials defined herein. In certain embodiments, elemental sulfur may be used as fertilizer coating. The coating may be performed by spraying molten S over urea granules, followed by an application of sealant wax to close fissures in the coating. In a further embodiment, the S layer may be covered with a layer of organic polymers, preferably a thin layer of organic polymers. In another embodiment, the coated fertilizers are preferably physical mixtures of coated and non- coated fertilizers.

Further envisaged coated fertilizers may be provided by reacting resin-based polymers on the surface of the fertilizer granule. A further example of providing coated fertilizers includes the use of low permeability polyethylene polymers in combination with high permeability coatings. In specific embodiments the composition and/or thickness of the fertilizer coating may be adjusted to control, for example, the nutrient release rate for specific applications. The duration of nutrient release from specific fertilizers may vary, e.g. from several weeks to many months. The presence of at least two nitrification inhibitors (compound I and compound II) in a mixture with coated fertilizers may accordingly be adapted. It is, in particular, envisaged that the nutrient release involves or is accompanied by the release of at least two nitrification inhibitors (compound I and compound II) according to the present invention.

Coated fertilizers may be provided as controlled release fertilizers (CRFs). In specific embodi ments these controlled release fertilizers are fully coated NPK fertilizers, which are homogeneous and which typically show a pre-defined longevity of release. In further embodiments, the CRFs may be provided as blended controlled release fertilizer products which may contain coated, uncoated and/or slow release components. In certain embodiments, these coated fertilizers may additionally comprise micronutrients. In specific embodiments these fertilizers may show a pre-defined longevity, e.g. in case of NPK fertilizers.

Additionally, envisaged examples of CRFs include patterned release fertilizers. These fertilizers typically show a pre-defined release patterns (e.g. hi/standard/lo) and a pre-defined longevity. In exemplary embodiments fully coated NPK, Mg and micronutrients may be delivered in a patterned release manner.

Also envisaged are double coating approaches or coated fertilizers based on a programmed release.

In further embodiments the fertilizer may be provided as, or may comprise or contain a slow re lease fertilizer. The fertilizer may, for example, be released over any suitable period of time, e.g. over a period of 1 to 5 months, preferably up to 3 months. Typical examples of ingredients of slow release fertilizers are IBDU (isobutylidenediurea), e.g. containing about 31-32 % nitrogen, of which 90% is water insoluble; or UF, i.e. an urea-formaldehyde product which contains about 38 % nitrogen of which about 70 % may be provided as water insoluble nitrogen; or CDU (cro- tonylidene diurea) containing about 32 % nitrogen; or MU (methylene urea) containing about 38 to 40% nitrogen, of which 25-60 % is typically cold water insoluble nitrogen; or MDU (methylene diurea) containing about 40% nitrogen, of which less than 25 % is cold water insoluble nitrogen; or MO (methylol urea) containing about 30% nitrogen, which may typically be used in solutions; or DMTU (diimethylene triurea) containing about 40% nitrogen, of which less than 25% is cold water insoluble nitrogen; or TMTU (tri methylene tetraurea), which may be provided as component of UF products; or TMPU (tri methylene pentaurea), which may also be provided as component of UF products; or UT (urea triazone solution) which typically contains about 28 % nitrogen. The fertilizer mixture may also be long-term nitrogen-bearing fertiliser containing a mixture of acetylene diurea and at least one other organic nitrogen-bearing fertiliser selected from methylene urea, isobutylidene diurea, crotonylidene diurea, substituted triazones, triuret or mixtures thereof. Any of the above mentioned fertilizers or fertilizer forms may suitably be combined. For instance, slow release fertilizers may be provided as coated fertilizers. They may also be com bined with other fertilizers or fertilizer types.

The term "fertigation" as used herein refers to the application of fertilizers, optionally soil amendments, and optionally other water-soluble products together with water through an irrigation system to a plant or to the locus where a plant is growing or is intended to grow, or to a soil substituent as defined herein below. For example, liquid fertilizers or dissolved fertilizers may be provided via fertigation directly to a plant or a locus where a plant is growing or is intended to grow. Likewise, nitrification inhibitors according to the present invention, or in combination with additional nitrification inhibitors, may be provided via fertigation to plants or to a locus where a plant is growing or is intended to grow. Fertilizers and nitrification inhibitors according to the present invention, or in combination with additional nitrification inhibitors, may be provided together, e.g. dissolved in the same charge or load of material (typically water) to be irrigated. In further embodiments, fertilizers and nitrification inhibitors may be provided at different points in time. For example, the fertilizer may be fertigated first, followed by the nitrification inhibitor, or preferably, the nitrification inhibitor may be fertigated first, followed by the fertilizer. The time intervals for these activities follow the herein above outlined time intervals for the application of fertilizers and nitrification inhibitors. Also envisaged is a repeated fertigation of fertilizers and nitrification inhibitors according to the present invention, either together or intermittently, e.g. every 2 hours, 6 hours, 12 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days or more.

The present invention is further illustrated by the following examples.

Experimental

Nl application

Fertilizer granules are added to rotating disk mixer. While mixing, nitrification inhibitor formulation is sprayed onto the fertilizer using a syringe. After 3 minutes mixing time, the fertilizer is removed from the mixer.

Anti-caking agent application

Anti-caking agent is heated to above its melting point. Fertilizer granules are heated to the same temperature as the anti-caking agent and added to a rotating disk mixer. Under continuous mixing, 0.1 wt% anti-caking agent is applied to the fertilizer using a syringe. After 3 minutes mixing time, the fertilizer is removed from the mixer.

Caking test

Two metal cylinders, diameter 55 mm, are placed on top of each other and the resulting cylinder is filled with 170 gram fertilizer. The fertilizer in the cylinder is put under 2.0 bar pressure for 24 hours at 30°C and 40% relative humidity. Afterwards, the cylinder is depressurized and the force needed to break the granules apart is measured. Higher force needed indicates more cak ing.

Fertilizer water content measurement 10 g fertilizer is weighed out in a petri dish and placed in an oven at 80°C for 4 hours. After wards the fertilizer is weighed back. The moisture content is calculated from the difference in fertilizer weight before and after drying.

Examples

Caking test

The caking test results show that only anti-caking agent D, containing a mixture of alkylamine and alkyl fatty acid, is able to reduce caking of Vibelsol treated ASN.