WO2022268777A1

WO2022268777A1 - Combination of a pyrazole and a thiophosphoric triamide

Info

Publication number: WO2022268777A1
Application number: PCT/EP2022/066827
Authority: WO
Inventors: Dirk Schmalz; Jonas Marius MARX
Original assignee: Wocklab Gmbh & Co. Kg
Priority date: 2021-06-23
Filing date: 2022-06-21
Publication date: 2022-12-29
Also published as: EP4359368A1

Abstract

The invention relates to a non-aqueous solution comprising or essentially consisting of (i) a pyrazole of general formula (I) or an agriculturally acceptable salt thereof; (ii) a thiophosphoric triamide of general formula (II); (iii) a carboxylic acid or carboxylic acid anhydride; (iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; and (v) optionally, a tracer.

Description

Combination of a pyrazole and a thiophosphoric triamide

[0001] Priority is claimed of European patent application no. 21181131.0 that was filed on June 23, 2021

[0002] The invention relates to an essentially non-aqueous solution comprising or essentially consisting of (i) a pyrazole of general formula (I) or an agriculturally acceptable salt thereof; (ii) a thiophosphoric triamide of general formula (II); (iii) a carboxylic acid or carboxylic acid anhydride; (iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; and (v) optionally, a tracer.

[0003] Nitrification is an aerobic process performed by small groups of autotrophic bacteria and ar- chaea. It is an important step in the nitrogen cycle in soil, wherein ammonia is biologically oxidized to nitrite, followed by the oxidation of the nitrite to nitrate. Nitrification of nitrogen-containing fertilizers reduces their efficiency, as the contained nitrogen is oxidized and no longer available for take up by crops. Therefore, nitrogen containing fertilizers commonly comprise nitrification inhibitors to reduce nitrification, when the fertilizer is applied to the soil.

[0004] Negative side effects of nitrogen-containing fertilizers, such as the production of nitrate ions to be washed out into the subterranean water and/or the production of nitrous fumes, in particular N O which is/are further identified to enhance the climate change, are of growing public concern. Both effects are based on metabolic activities of soil bacteria, which - in several steps - turn urea and other nitrogen- containing fertilizers into N O and/or nitrate ions.

[0005] The key enzymes involved in nitrification can effectively be inhibited by nitrification inhibitors. The use of nitrification inhibitors to reduce negative side effects of nitrogen containing fertilizers, such as the production of nitrate ions and nitrous gases, has significantly grown in recent years. The enzymes involved in this step can be inhibited by known nitrification inhibitors such as pyrazole derivatives. 3,4- Dimethylpyrazol (3,4 DMP) and its phosphate salt 3,4-dimethylpyrazol-phosphate (3,4 DMPP) are the most widely discussed and used ones.

[0006] Urea is the most widely applied nitrogen-containing fertilizer. Urea-containing fertilizers have the disadvantage of undergoing considerable losses of ammonia gas if not incorporated into soil soon after application, due to the conversion of urea into ammonia and carbon dioxide by the naturally oc curring enzyme urease. Urease is produced by many soil microorganisms and plants, and is present in nearly all soils. Urease inhibitors are used to temporarily reduce the activity of the enzyme and slow the rate at which urea is hydrolyzed.

[0007] There are many compounds that can inhibit urease, but only a few that are non-toxic, effective at low concentrations, chemically stable and able to be mixed with or coated onto urea-containing ferti lizers. The most widely used urease inhibitor is N-(n-Butyl)thiophosphoric triamide (NBTPT or NBPT).

[0008] Formulations comprising a nitrification inhibitor and/or a urease inhibitor are commonly used as fertilizer additive.

[0009] US 2015/299062 A1 relates to increasing longevity of the nitrogen content of soil through im proved liquid delivery formulations of nitrification inhibitors. The liquid formulation can also be com prised of nitrification inhibitors and optionally urease inhibitors that are blended solutions of each. The nitrification inhibitors are present in a mixture that comprises both a protic and an aprotic solvent system. The novel formulations are designed to be applied to fertilizers, especially urea and manure based ferti lizers.

[0010] US 2017/0253535 A1 discloses an improved nitrification inhibitor composition comprising UFP particles and a nitrification inhibitor, and optionally other components, which is used as an additive for liquid and solid fertilizers, typically containing urea. The nitrification inhibitor particularly can be nitra- pyrin and/or DMPP. Methods of making the compositions and their use are also disclosed.

[0011] US 2018/0002244 A1 provides novel agricultural microbial inoculant compositions for uses in promoting plant growth, plant productivity and/or soil quality. The novel microbial inoculant composi tions comprise one or more microbial species, one or more urease inhibitors and/or one or more nitrifi cation inhibitors.

[0012] US 2018/0208520 A1 discloses reaction products and methods for making and using such reac tion products.

[0013] US 2019/0048260 A1 provides a nitrogen stabilizing composition. The composition includes 22 to 26% w/w N-(n-butyl) thiophosphoric triamide (NBPT), 4 to 8% w/w of 3,4-dimethyl pyrazole phos phate (DMPP) and/or nitrapyrin, a solvent including N-methyl-2-pyrrolidone (NMP) and propylene gly col, 0.1 to 5% w/w vegetable oil, and 0.1 to 5% w/w lecithin. [0014] US 2019/0124917 A1 provides novel microbial inoculant compositions for uses in promoting plant growth, plant productivity and/or soil quality. The novel microbial inoculant compositions com prise one or more microbial species, one or more urease inhibitors and/or nitrification inhibitors.

[0015] WO 2019/012382 A1 relates to mixtures comprising as active components at least one specific nitrification inhibitor (compound I) and at least one urease inhibitor(compound II); to a method for improving the nitrification-inhibiting effect, or for increasing the health of a plant using mixtures of at least one compound I and at least one compound II; to the use of mixtures comprising compounds I and compounds II for increasing the health of a plant; to agrochemical compositions comprising these mix tures; and to plant propagation material, comprising these mixtures or these agrochemical compositions.

[0016] AU 2021 100 557 A4 relates to a urea fertilizer, and particularly relates to a carbon-nitrogen- coupled stabilized nitrogen fertilizer and a preparation method. Components of the fertilizer include urea, biochemical inhibitor for regulating a soil transformation process of nitrogen and a carbon-con taining material, wherein the type of the nitrogen fertilizer is urea; and the biochemical inhibitor mainly includes urease inhibitor and nitrification inhibitor, and the carbon-containing material is y-polyglu- tamic acid.

[0017] CN 105 669 332 B discloses a paddy field nitrogen fertilizer synergist and its application method. The paddy field nitrogen fertilizer synergist is formed by mixing a urease inhibitor and a nitri fication inhibitor according to the weight ratio of 2-5 : 1. The urease inhibitor and the nitrification inhib itor are obtained by compounding-mixing technology of layered coating or single coating. NBPT (N- (n-Butyl)thiophosphoric triamide) is selected as the urease inhibitor, and DMPP (3,4-dimethylpyrazole phosphate) is selected as the nitrification inhibitor.

[0018] CN 108 264 439 A relates to heavy metal cadmium passivation repair slow-release multifunc tional urea fertilizer and a preparation method. The fertilizer comprises urea, a biochemical inhibitor, asoil heavy metal cadmium passivation material, water-soluble salt ions of medium-trace elements needed by plants and/or beneficial elements for plant growth.

[0019] CN 109 232 137 A discloses urine fertilizer, in particular carbon coupled stable nitrogen ferti lizer and a preparation method thereof. The fertilizer is prepared from the following ingredients of urine, a biochemical inhibitor used for regulating a nitrogen soil conversion process, and a carbon-containing material, wherein the type of the nitrogen fertilizer is urine, the biochemical inhibitor mainly contains a urease inhibitor and a nitrification inhibitor, and the carbon-containing material is gamma-polyglutamic acid. [0020] CN 110 922258 A relates to a functional stable bulk blending fertilizer as well as a preparation method and application thereof. The functional stable bulk blending fertilizer comprises a mixed ferti lizer, a composite inhibitor, a fdler, a functional auxiliary agent and potassium chloride, wherein the mixed fertilizer is prepared from urea, calcium superphosphate and diammonium phosphate; wherein the composite inhibitor is prepared from o-phenyl phosphoramide, thiophosphoric triamide, 3, 4-dime thyl pyrazole phosphate, dicyandiamideand chloromethylpyridine; wherein the composite inhibitor co vers the surface of the mixed fertilizer; wherein the functional auxiliary agent is prepared from biochar, humic acid, polyglutamic acid, ammonium polyphosphate, arginine, polyacrylamide, 1, 2-hexanediol, dipotassium glycyrrhizinate, an ascophyllum nodosum extract and chitosan; and the functional additive coats the surface of the filler.

[0021] CN 110 981 641 A discloses a solid blended fertilizer containing coated synergistic urea and ammonium nitrate phosphate, and a preparation method thereof, wherein the fertilizer takes the coated synergistic urea, the ammonium nitrate phosphate and a water absorbent as raw materials, a mass ratio of the coated synergistic urea to the ammonium nitrate phosphate to the water absorbent is (10-95):(10- 95):(l-5), and the coated synergistic urea is prepared from the following components in percentage by mass: 90-95% of urea, 0.5-3% of a binding agent, 1.5-7% of a coating material and 0.1-0.5% of a syn ergist.

[0022] CN 112 374 950 A relates to a nitrogen fertilizer synergist as well as a preparation method and application thereof. The nitrogen fertilizer synergist comprises a urease inhibitor, a nitrification inhibi tor, a raw material, a nitrogen stabilizer, a carrier and a filler, and is characterized in that the denitrifi cation inhibitor is a procyanidine crude product mixture extracted from a plant source; and the urease inhibitor, the nitrification inhibitor, the raw material, the nitrogen stabilizer, the carrier and the filler are mixed according to a weight part ratio of 1: 0.25-2:0.5-2:0.05-0.6:0.5-1:0.25-2.

[0023] However, the formulations comprising nitrification inhibitors and urease inhibitors of the prior art are not satisfactory in every respect. There is a demand for an improved formulation which comprises a nitrification inhibitor and a urease inhibitor in combination with one another (co-formulation) and which is useful as fertilizer additive. For that purpose, the formulation (fertilizer additive) needs to be applied to a solid fertilizer, preferably by coating, spraying and/or impregnating, wherein the fertilizer is typically in the form of granules, prills, pellets, pastilles, or a compounded form. The thus prepared fertilizer is then used afield.

[0024] For effective and satisfactory applicability onto solid fertilizers, the formulation comprising ni trification inhibitor and urease inhibitor (fertilizer additive) should be a liquid essentially having no undissolved constituents. Thus, in other words, the formulation (fertilizer additive) should be a solution of the nitrification inhibitor and of the urease inhibitor in a suitable solvent, but it should not be a dis persion, especially not a suspension. As applying the formulation (fertilizer additive) onto a solid ferti lizer may involve pumping and/or spraying steps, undissolved constituents would have a negative im pact on applicability.

[0025] Further, the formulation (fertilizer additive) should have sufficient storage stability, i.e. the ni trification inhibitor and the urease inhibitor should remain active when the formulation is stored before it is used as fertilizer additive, i.e. before it is applied onto a solid fertilizer and subsequently used afield. Chemical decomposition and crystallization during storage of the formulation (fertilizer additive) should be avoided. Crystallization of the formulation (fertilizer additive) may occur especially at lower temper atures during delivery and redissolution may require a certain amount of time and equipment.

[0026] Still further, the formulation (fertilizer additive) should contain the nitrification inhibitor and the urease inhibitor at comparatively high concentrations. This requirement is of particular concern, as certain nitrification inhibitors and/or urease inhibitors have either limited stability or limited solubility in certain solvents or solvent systems, which in turn of course need to be agriculturally acceptable. In particular, DMP has conventionally been provided in the form of its phosphate salt (DMPP) which is primarily soluble in polar solvents such as water. However, aqueous compositions are not compatible with the other active ingredient of the combination, i.e. the urease inhibitor, because certain urease in hibitors such as NBPT spontaneously hydrolyze in aqueous environment and thus are not storage stable in aqueous solution.

[0027] Co-formulations comprising both a nitrification inhibitor and a urease inhibitor are therefore limited by the provision of suitable non-aqueous solvents. Pyrrolidones, such as N-methyl-2-pyrrolidone (NMP), may in principle be suitable to dissolve both active ingredients, nitrification inhibitors such as DMP and urease inhibitors such as NBPT. However, since NMP is toxic, it is not a suitable solvent for fertilizers that are to be applied to soil or plants. Methanol is also a suitable solvent, but it is likewise toxic and quickly evaporates.

[0028] Yet further, once applied to the solid fertilizer, the formulation (fertilizer additive) should ensure that considerable amounts of the nitrification inhibitor and the urease inhibitor remain on the solid fer tilizer, e.g. on the granules, prills, pellets, pastilles, and the like, so that they can evolve their effect once the thus prepared fertilizer is subsequently used overland, i.e. afield. This is of particular concern, as certain nitrification inhibitors such as DMP have a low vapor pressure such that they tend to evaporate over time. While the formulation (fertilizer additive) may be stored in a closed container thereby avoid ing evaporation and may be applied to the solid fertilizer shortly before being used overland, loss of nitrification inhibitor by evaporation should at least be reduced or even be completely avoided, after the formulation (fertilizer additive) has been applied to the solid fertilizer and when the thus prepared ferti lizer is used afield. Modifications of DMP in order to reduce its vapor pressure such as forming salts of DMP (e.g. the phosphate salt DMPP) are no option because they render the DMP salts insoluble or at least sparingly soluble in many non-aqueous solvents.

[0029] Summarizing therefore there is a demand for compositions which

(i) comprise a combination of both nitrification inhibitor such as DMP and urease inhibitor such as NBPT (co-formulations) at comparatively high weight contents (concentrations);

(ii) can be applied onto solid fertilizers by conventional application technology such as spraying;

(iii) are agriculturally acceptable;

(iv) have satisfactory or improved storage stability; and

(v) provide satisfactory or improved agricultural performance when being used afield.

[0030] It is an object of the invention to provide co-formulations which comprise a nitrification inhib itor such as DMP and a urease inhibitor such as NBPT and which are useful as fertilizer additive satis fying one or more, preferably all of the above needs (i) through (v).

[0031] This object has been achieved by the subject-matter of the patent claims.

[0032] It has been surprisingly found that co-formulations comprising both a nitrification inhibitor such as DMP and an urease inhibitor such as NBPT can be provided in non-aqueous solvents, wherein the urease inhibitor and the nitrification inhibitor are present in dissolved form at satisfactory concentra tions. A particularly suitable non-aqueous solvent is polyalkylene glycol, preferably polyethylene gly col, which exhibits an adequate viscosity while being neither toxic nor harmful to the environment.

[0033] Further, it has been surprisingly found that the tendency of DMP to evaporate from solutions in non-aqueous polyalkylene glycol, preferably polyethylene glycol is significantly reduced. In particular, it has been surprisingly found that said tendency of DMP to evaporate from solutions in polyalkylene glycol, preferably polyethylene glycol is not only significantly reduced compared to free DMP alone, i.e. in the absence of any solvent, but is additionally also significantly reduced compared to solutions of DMP in other non-aqueous solvents such as butylene glycol. Thus, the combination of DMP with non- aqueous polyalkylene glycol, preferably polyethylene glycol has specific advantages that do not exist for combinations of DMP with other non-aqueous solvents.

[0034] In consequence, conventional modifications of DMP that might otherwise be considered in order to increase the vapor pressure of DMP, e.g. providing DMP in form of its phosphate salt (DMPP), are not needed. Hence, more polar solvents such as water may be omitted accordingly thereby taking ac count of the poor stability of the urease inhibitor NBPT in water. In the absence of water, polyalkylene glycol, preferably polyethylene glycol is also a good solvent for NBPT without deteriorating its chemical stability; hydrolysis of NBPT is prevented due to the absence of water.

[0035] The non-aqueous solutions according to the invention that contain DMP and NBPT at compar atively high concentrations in polyalkylene glycol, preferably polyethylene glycol can be applied, e.g. sprayed, onto solid fertilizers, e.g. prills, by conventional application technology without blocking equipment such as spray nozzles.

[0036] Therefore, the non-aqueous solutions of DMP and NBPT in polyalkylene glycol, preferably polyethylene glycol according to the invention have advantages with respect to (i) solubility and con centration of dissolved DMP and NBPT, (ii) applicability onto solid fertilizers by conventional applica tion technology such as spraying, (iii) environmental and agricultural compatibility, (iv) storage stabil ity, and (v) agricultural performance (nitrification and urease inhibition).

[0037] Still further, it has been surprisingly found that the stability and retention of DMP, once applied to plant or soil, can be further improved by the in-situ formation of an agriculturally acceptable acid addition salt of DMP with certain carboxylic acids. As already mentioned above, DMP as such has been found to evaporate quickly shortly after application to plant or soil due to its high vapor pressure, whereas an agriculturally acceptable acid addition salt of DMP has a lower vapor pressure and thus a prolonged availability to soil and plants. While agriculturally acceptable acid addition salts of DMP such as 3,4-dimethylpyrazol-phosphate (DMPP) are weakly soluble in non-toxic and water-free solvents such as polyalkylene glycols, preferably polyethylene glycols, DMP as such has been further found to have sufficient solubility in these solvents, also in the presence of agriculturally acceptable acids, to enable the subsequent in-situ formation of such agriculturally acceptable acid addition salts of DMP.

[0038] Yet further, it has been surprisingly found that carboxylic acids such as citric acid, malic acid, heptanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, and maleic acid are especially suitable to provide formulations which enable the in-situ formation of agri culturally acceptable acid addition salts of DMP after application to soil or plant. Solutions of a nitrifi cation inhibitor such as DMP and carboxylic acids in non-aqueous solvents such as polyalkylene glycols, preferably polyethylene glycols are stable and the nitrification inhibitor as well as the carboxylic acids remain in solution; no acid addition salts e.g. DMP carboxylates precipitate from solution. Thus, even if in solution DMP to a certain extent is protonated by the carboxylic acids, the non-aqueous solvents such as polyalkylene glycols, preferably polyethylene glycols are capable of dissolving the thus formed ion-pairs and no precipitation of salts (DMP carboxylates) is observed. Once these solutions are applied to plant or soil, they will be exposed to rain and other water sources. Without wishing to be bound to any scientific theory, it appears that in aqueous environment salt formation will then occur which pro tects DMP against (i) hydrolysis and (ii) evaporation.

[0039] Furthermore, it has been found that carboxylic acid anhydrides, preferably maleic acid anhy dride, can act as drying agent for the solution according to the invention and in particular for the non- aqueous solvent such as polyalkylene glycols, preferably polyethylene glycols. The carboxylic acid an hydride is capable of reacting with minor amounts of water which may be comprised in the solution thereby forming the respective carboxylic acid. Thus, undesirable hydrolyzation of the urease inhibitor such as NBPT can be reduced.

[0040] Moreover, it has been found that co-formulations of a nitrification inhibitor such as DMP and a urease inhibitor such as NBPT comprising a carboxylic acid or a carboxylic acid anhydride, preferably a carboxylic acid anhydride, are stable even at low temperatures e.g. of 0°C. All ingredients stay in solution and no crystallization occurs at these low temperatures. Further, it has been found that even solutions comprising a relatively high amount of DMP such as 27.5 wt.-%, relative to the total weight of the solution, are stable at low temperatures and no crystallization occurs, when a carboxylic acid or carboxylic acid anhydride is contained.

[0041] Further, it has been surprisingly found that the effect of non-aqueous polyalkylene glycol, pref erably polyethylene glycol that counteracts evaporation of DMP is even more pronounced in the pres ence of a carboxylic acid or a carboxylic acid anhydride. Non-aqueous solutions of DMP in polyalkylene glycol, preferably polyethylene glycol in the presence of a carboxylic acid or a carboxylic acid anhydride have a significantly lower tendency to release DMP by evaporation compared to non-aqueous solutions of DMP in other solvents such as butylene glycol in the presence of the carboxylic acid or carboxylic acid anhydride.

[0042] Still further, it has been surprisingly found that fertilizer compositions comprising a nitrification inhibitor such as DMP as well as a urease inhibitor such as NBPT can be easily prepared from such co formulations comprising non-aqueous polyalkylene glycol, preferably polyethylene glycol. Instead of applying two compositions each separately comprising one inhibitor, both inhibitors can be applied to fertilizer compositions by means of only one co-formulation and in only one application step. As no aqueous solvents are necessary to dissolve the nitrification inhibitor such as DMP, undesirable hydroly zation of the urease inhibitor such as NBPT can be reduced. Thus, fertilizer compositions comprising a nitrification inhibitor such as DMP as well as a urease inhibitor such as NBPT can be produced in an easy and efficient process which reduces hydrolyzation of the urease inhibitor thus providing fertilizer compositions comprising both inhibitors at satisfactory concentrations. Further, stability and retention of DMP in the fertilizer composition may be further improved by the in-situ formation of the agricultur ally acceptable acid addition salt of DMP with the carboxylic acid.

[0043] A first aspect of the invention relates to an essentially non-aqueous solution comprising or es sentially consisting of

(i) a pyrazole of general formula (I)

wherein

R1 means -H, -Ci-e -alkyl, or -Ci-e-alkyl-OH; preferably -H;

R2 means -H, -Ci-e -alkyl, -Ci-e-alkyl-OH, -Nth, -F, -Cl, or -Br; preferably -H;

R3 and R4 independently of one another mean -H, -CYr, -alkyl. -CY₍, -alkyl -OH. -NFfi, -F, -Cl, or -Br; preferably -CFfi; or an agriculturally acceptable salt thereof; preferably 3,4-dimethylpyrazole or an agriculturally acceptable salt thereof;

(ii) a thiophosphoric triamide of general formula (II)

wherein

R5 means -H, -Ci-₂₀-alkyl, -C_3-20-cycloalkyl, -C₃-io-aryl, -di(Ci-₂₀-alkyl)aminocarbonyl, - di(C_3-20-cycloalkyl)aminocarbonyl, -di(C₃-io-aryl)aminocarbonyl; preferably -H;

R6 means -H, -Ci-₂₀-alkyl, -C_3-20-cycloalkyl, -C₃-io-aryl, -di(Ci-₂₀-alkyl)aminocarbonyl, - di(C_3-20-cycloalkyl)aminocarbonyl, -di(C₃-io-aryl)aminocarbonyl; preferably -Ci-₂₀-alkyl; preferably N-(n-butyl)thiophosphoric triamide;

(iii) optionally, a carboxylic acid or carboxylic acid anhydride; preferably a carboxylic acid; more preferably in its non-salt form; (iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; and

(v) optionally, a tracer.

[0044] For the purpose of the specification, unless expressly stated otherwise, all standards such as ASTM, EN ISO and the like refer to the version that is valid on the filing date. Further, unless expressly stated otherwise, all conditions are normal temperature and pressure, i.e. a temperature of 20 °C (293.15 K, 68 °F) and an absolute pressure of 1 atm (14.696 psi, 101.325 kPa).

[0045] For the purpose of the specification, a "fertilizer composition" comprises a fertilizer and option ally additional ingredients, preferably the essentially non-aqueous solution (fertilizer additive) accord ing to the invention.

[0046] For the purpose of the specification, a "fertilizer" is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply one or more plant nutrients essential to the growth of plants. Many sources of fertilizer exist, both natural and industrially produced. They typically provide the three main macronutrients nitrogen, phosphorus, and potassium in varying proportions. The mainly used nitrogen containing fertilizers comprise ammonium compounds or derivatives thereof.

[0047] For the purpose of the specification, a "fertilizer additive " is a composition that can be advanta geously added to (conventional) fertilizers in order to improve their properties. Typically, the fertilizer additive is no fertilizer as such.

[0048] Certain ingredients can be added or may be present in the solution according to the invention in form of agriculturally acceptable salts of carboxylic acids, pyrazoles, and the like. Unless expressly stated otherwise, all percentages and weights refer to the corresponding weight of the non-salt forms, i.e. the free acids and the free pyrazole, i.e. the weight contribution of the salt component is not taken into account.

[0049] For the purpose of the specification, unless expressly stated otherwise, " essentially consisting of or "essentially the total amount" means at least 95 wt.-%, preferably at least 98 wt.-%, more prefer ably at least 99 wt.-%.

[0050] The essentially non-aqueous solution according to the invention is a solution, i.e. the contained components are preferably completely solved. [0051] For the purpose of the specification, a "solution" does not encompass dispersions such as sus pensions or emulsions. Thus, the solution according to the invention contains all ingredients in substan tially dissolved form.

[0052] The solution according to the invention is essentially non-aqueous. For the purpose of the spec ification, "essentially non-aqueous " refers to a composition (solution) to which no water has been ac tively added but which may comprise minor amounts of water, e.g. entrained from air humidity or pre sent as an impurity in a starting material such as polyalkylene glycol, preferably polyethylene glycol. Preferably, the solution according to the invention has a water content of at most 5 wt.-%, preferably at most 2.5 wt.-%, more preferably at most 1.0 wt.-%, still more preferably at most 0.9 wt.-%, yet more preferably at most 0.8 wt.-%, even more preferably at most 0.7 wt.-%, most preferably at most 0.6 wt.- %, and in particular at most 0.5 wt.-%. Preferably, the solution according to the invention has a water content of at most 0.4 wt.-%, preferably at most 0.3 wt.-%, more preferably at most 0.2 wt.-%, still more preferably at most 0.1 wt.-%, yet more preferably at most 0.05 wt.-%, even more preferably at most 0.01 wt.-%, most preferably at most 0.005 wt.-%, and in particular at most 0.001 wt.-%; preferably comprises no water at all.

[0053] In preferred embodiments, the solution according to the invention comprises the carboxylic acid or carboxylic acid anhydride, or mixtures thereof. Preferably, the carboxylic acid anhydride reacts with minor amounts of water which may be comprised in the solution according to the invention, e.g. en trained from air humidity or present as an impurity in a starting material such as polyalkylene glycol, preferably polyethylene glycol, thereby forming the respective carboxylic acid. Thus, the carboxylic acid anhydride preferably acts as water scavenger.

[0054] For the purpose of the specification, unless expressly stated otherwise, "an agriculturally ac ceptable salt of pyrazole" means an acid addition salt of pyrazole with the carboxylic acid or carboxylic acid anhydride. Preferably not 3,4-dimethylpyrazole phosphate.

[0055] The solution according to the invention may contain one or more pyrazoles of general formula (I) or agriculturally acceptable salts thereof. Preferably, the solution according to the invention contains a single pyrazole of general formula (I) or an agriculturally acceptable salt thereof.

[0056] Preferably, the carboxylic acid or carboxylic acid anhydride protonates the pyrazole thereby forming an agriculturally acceptable salt thereof, wherein the protonated pyrazole forms a cation and the anion is formed by the deprotonated carboxylic acid or carboxylic acid anhydride. [0057] In particularly preferred embodiments, the pyrazole is added to the solution according to the invention in the non-salt form. In these embodiments, the pyrazole is preferably present in the non-salt form in the solution. Preferably, an agriculturally acceptable acid addition salt of the pyrazole with the carboxylic acid or carboxylic acid anhydride is not formed until the solution is applied to the plant or soil. Preferably, the carboxylic acid or carboxylic acid anhydride does not form a Michael adduct with the pyrazole or agriculturally acceptable salt thereof, neither under the conditions in solution nor when applied to the plant or soil.

[0058] It is contemplated that when a carboxylic acid anhydride is used, this functions as a precursor for the respective carboxylic acid. Preferably, the carboxylic acid anhydride forms the respective car boxylic acid upon reaction with water. The water is preferably already contained in the solution in minor amounts and/or is present when the solution or the fertilizer composition according to the invention is applied to the plant or soil.

[0059] Preferably, the pyrazole is selected from the group consisting of pyrazole, 3,4-dimethylpyrazole, 3,5-dimethylpyrazole, 4-chloro-3-methylpyrazole, 5-chloro-l,3-dimethylpyrazole, 5-amino-l,3-dime- thylpyrazole, 3,5-dimethylpyrazole-l-methanol, l-allyl-3,5-dimethylpyrazole, l-(2-hydroxyethyl)-py- razole, 1 -methyl- li/-pyrazole-4-carboxaldehyde, l /-pyrazolc-3-carbaldchydc. l /-pyrazole-5-carbal- dehyde, li/-pyrazole-3 -carboxylic acid, 2i7-pyrazole-3 -carboxylic acid, 1.5-dimethyl- l /-pyrazole-4- carboxylic acid, 4-bromo-l, 3-dimethyl- li/-pyrazole-5 -carboxylic acid, li/-pyrazole-4, 5-diamine, or an agriculturally acceptable salt thereof.

[0060] In particularly preferred embodiments, the pyrazole is 3,4-dimethylpyrazole (DMP) or an agri culturally acceptable salt thereof.

[0061] Preferably, the pyrazole is at least partially present in the non-salt form.

[0062] Preferably, the pyrazole is at least partially present in form of an agriculturally acceptable salt; preferably not 3,4-dimethylpyrazole phosphate.

[0063] Preferably, the pyrazole is at least partially present in form of an agriculturally acceptable acid addition salt with the carboxylic acid or carboxylic acid anhydride.

[0064] Preferably, the pyrazole is present in the non-salt form and/or in form of an agriculturally ac ceptable acid addition salt with the optionally present carboxylic acid or carboxylic acid anhydride. After at least partial hydrolysis with minor amounts of water which may be contained in the solution according to the invention, the carboxylic acid anhydride may form the respective carboxylic acid and agriculturally acceptable acid addition salt with the pyrazole. Preferably, the agriculturally acceptable acid addition salt is not 3,4-dimethypyrazole phosphate (DMPP).

[0065] In the solution according to the invention, the pyrazole of general formula (I) may be present in the non-salt form or in the form of an agriculturally acceptable salt, preferably an agriculturally accepta ble acid addition salt with the carboxylic acid or carboxylic acid anhydride. Preferably, the pyrazole is completely in the non-salt form.

[0066] When the pyrazole of general formula (I) is present in the solution according to the invention partly in the non-salt form and partly in the form of an agriculturally acceptable salt, preferably an agriculturally acceptable acid addition salt with the carboxylic acid or carboxylic acid anhydride, pref erably, the weight content of the pyrazole in the non-salt form is at least 70 wt.-%, preferably at least 75 wt.-%, more preferably at least 80 wt.-%, still more preferably at least 85 wt.-%, yet more preferably at least 90 wt.-%, even more preferably at least 95 wt.-%, most preferably at least 99 wt.-%, and in partic ular at least 99.9 wt.-%, relative to the total weight of the pyrazole and the agriculturally acceptable salt thereof.

[0067] In preferred embodiments, the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 2.0 wt.-%, preferably at least 2.5 wt.-%, more preferably at least 3.0 wt.-%, still more preferably at least 3.5 wt.-%.

[0068] In preferred embodiments, the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 4.0 wt.-%, preferably at least 4.5 wt.-%, more preferably at least 5.0 wt.-%, still more preferably at least 5.5 wt.-%, yet more preferably at least 6.0 wt.-%, even more preferably at least 6.5 wt.-%, most preferably at least 7.0 wt.-%, and in particular at least 7.5 wt.-%; in each case relative to the total weight of the solution.

[0069] In preferred embodiments, the weight content of the pyrazole or agriculturally acceptable salt thereof is at most 11 wt.-%, preferably at most 10.5 wt.-%, more preferably at most 10 wt.-%, still more preferably at most 9.5 wt.-%, yet more preferably at most 9.0 wt.-%, even more preferably at most 8.5 wt.-%, most preferably at most 8.0 wt.-%, and in particular at most 7.5 wt.-%; in each case relative to the total weight of the solution.

[0070] In preferred embodiments, the weight content of the pyrazole or agriculturally acceptable salt thereof is within the range of 7.5±6.0 wt.-%, preferably 7.5±5.5 wt.-%, more preferably 7.5±5.0 wt.-%, still more preferably 7.5±4.5 wt.-%, yet more preferably 7.5±4.0 wt.-%, even more preferably 7.5±3.5 wt.-%, most preferably 7.5±3.0 wt.-%, and in particular 7.5±2.5 wt.-%; in each case relative to the total weight of the solution.

[0071] In preferred embodiments, the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 8.0 wt.-%, preferably at least 9.0 wt.-%, more preferably at least 10 wt.-%, still more preferably at least 11 wt.-%, yet more preferably at least 12 wt.-%, even more preferably at least 12.5 wt.-%, most lpreferably at least 13 wt.-%, and in particular at least 13.5 wt.-%.

[0072] In preferred embodiments, the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 14.0 wt.-%, preferably at least 14.5 wt.-%, more preferably at least 15.0 wt.-%, still more preferably at least 15.5 wt.-%, yet more preferably at least 16.0 wt.-%, even more preferably at least 16.5 wt.-%, most preferably at least 17.0 wt.-%, and in particular at least 17.5 wt.-%; in each case relative to the total weight of the solution.

[0073] In preferred embodiments, the weight content of the pyrazole or agriculturally acceptable salt thereof is at most 21 wt.-%, preferably at most 20.5 wt.-%, more preferably at most 20 wt.-%, still more preferably at most 19.5 wt.-%, yet more preferably at most 19.0 wt.-%, even more preferably at most 18.5 wt.-%, most lpreferably at most 18.0 wt.-%, and in particular at most 17.5 wt.-%; in each case relative to the total weight of the solution.

[0074] In preferred embodiments, the weight content of the pyrazole or agriculturally acceptable salt thereof is within the range of 17.5±6.0 wt.-%, preferably 17.5±5.5 wt.-%, more preferably 17.5±5.0 wt.- %, still more preferably 17.5±4.5 wt.-%, yet more preferably 17.5±4.0 wt.-%, even more preferably 17.5±3.5 wt.-%, most lpreferably 17.5±3.0 wt.-%, and in particular 17.5±2.5 wt.-%; in each case rela tive to the total weight of the solution.

[0075] Preferably, the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 5.0 wt.-%, or at least 10 wt.-%, or at least 15 wt.-%, or at least 20 wt.-%, or at least 25 wt.-%, or at least 30 wt.-%, or at least 35 wt.-%, or at least 40 wt.-%, or at least 45 wt.-%, or at least 50 wt.-%, or at least 55 wt.-%, or at least 60 wt.-%, relative to the total weight of the solution.

[0076] Preferably, essentially the total amount, more preferably all of the pyrazole or agriculturally acceptable salt thereof contained in the solution according to the invention is completely solved.

[0077] Preferably, the pyrazole or agriculturally acceptable salt thereof is a nitrification inhibitor. [0078] The solution according to the invention may contain one or more thiophosphoric triamides of general formula (II). Preferably, the solution according to the invention contains a single thiophosphoric triamide of general formula (II).

[0079] Preferably, the thiophosphoric triamide is selected from the group consisting of N-(n-butyl)thi- ophosphoric triamide, N-(n-propyl)thiophosphoric triamide, N-(cyclohexyl)thiophosphoric triamide and N-(2-nitrophenyl)thiophosphoric triamide.

[0080] Preferably, R5 represents -H.

[0081] Preferably, R6 represents -Ci-20-alkyl.

[0082] Preferably, R6 represents -n-butyl.

[0083] In particularly preferred embodiments, the thiophosphoric triamide is N-(n-butyl)thiophos- phoric triamide (NBPT). NBPT is commercially available.

[0084] In preferred embodiments, the weight content of the thiophosphoric triamide is at least 7.5 wt- %, preferably at least 10 wt.-%, more preferably at least 12.5 wt.-%, still more preferably at least 15 wt- %, yet more preferably at least 17.5 wt.-%, even more preferably at least 20 wt.-%, most preferably at least 22.5 wt.-%, and in particular at least 25 wt.-%; in each case relative to the total weight of the solution.

[0085] In preferred embodiments, the weight content of the thiophosphoric triamide is at most 42.5 wt- %, preferably at most 40 wt.-%, more preferably at most 37.5 wt.-%, still more preferably at most 35 wt.-%, yet more preferably at most 32.5 wt.-%, even more preferably at most 30 wt.-%, most preferably at most 27.5 wt.-%, and in particular at most 25 wt.-%; in each case relative to the total weight of the solution.

[0086] In preferred embodiments, the weight content of the thiophosphoric triamide is within the range of 25±12 wt.-%, preferably 25±11 wt.-%, more preferably 25±10 wt.-%, still more preferably 25±9.0 wt.-%, yet more preferably 25±8.0 wt.-%, even more preferably 25±7.0 wt.-%, most preferably 25±6.0 wt.-%, and in particular 25±5.0 wt.-%; in each case relative to the total weight of the solution.

[0087] Preferably, essentially the total amount, more preferably all of the thiophosphoric triamide con tained in the solution according to the invention is completely solved. [0088] In preferred embodiments, the weight content of the thiophosphoric triamide is greater than the weight content of the pyrazole or agriculturally acceptable salt thereof.

[0089] In preferred embodiments, the relative weight ratio of the pyrazole or agriculturally acceptable salt thereof to the thiophosphoric triamide is at least 0.16, preferably at least 0.18, more preferably at least 0.20, still more preferably at least 0.22, yet more preferably at least 0.24, even more preferably at least 0.26, most preferably at least 0.28, and in particular at least 0.30.

[0090] In preferred embodiments, the relative weight ratio of the pyrazole or agriculturally acceptable salt thereof to the thiophosphoric triamide is at most 0.70, preferably at most 0.65, more preferably at most 0.60, still more preferably at most 0.55, yet more preferably at most 0.49, even more preferably at most 0.46, most preferably at most 0.43, and in particular at most 0.40.

[0091] In preferred embodiments, the relative weight ratio of the pyrazole or agriculturally acceptable salt thereof to the thiophosphoric triamide is within the range of from l:7 to 1: 1.1, preferably from 1:6.5 to 1:1.3, more preferably from l:6 to 1: 1.5, still more preferably from 1:5.5 to 1:1.7, yet more preferably from 1:5 to 1: 1.9, even more preferably from 1:4.5 to 1:2.1, most preferably from 1:4 to 1:2.3, and in particular from 1:3.5 to 1:2.5.

[0092] Preferably, the thiophosphoric triamide is a urease inhibitor.

[0093] The solution according to the invention preferably comprises a carboxylic acid or carboxylic acid anhydride. The solution according to the invention may contain one or more carboxylic acids or carboxylic acid anhydrides. Preferably, the solution according to the invention contains a single carbox ylic acid or carboxylic acid anhydride.

[0094] When the solution according to the invention comprises a carboxylic acid, the carboxylic acid is preferably added in its non-salt form, i.e. in its fully protonated state.

[0095] Preferably, the carboxylic acid or carboxylic acid anhydride is a carboxylic acid.

[0096] Preferably, the carboxylic acid or carboxylic acid anhydride is an aliphatic carboxylic acid or an aromatic carboxylic acid; preferably a saturated aliphatic carboxylic acid, an unsaturated aliphatic carboxylic acid or an aromatic carboxylic acid; or a carboxylic acid anhydride of any of the foregoing. [0097] Preferably, the carboxylic acid or carboxylic acid anhydride is a saturated aliphatic carboxylic acid or an aromatic carboxylic acid. For the purpose of the specification, unless expressly stated other wise, the term " aromatic carboxylic acid " includes heterocyclic aromatic carboxylic acids.

[0098] In preferred embodiments, the carboxylic acid or carboxylic acid anhydride is a monocarboxylic acid; preferably an aliphatic monocarboxylic acid or an aromatic monocarboxylic acid; more preferably heptanoic acid, salicylic acid, gallic acid, or nicotinic acid; or a carboxylic acid anhydride of any of the foregoing.

[0099] In these preferred embodiments, the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is

- at least 0.65, preferably at least 0.7, more preferably at least 0.75, still more preferably at least 0.8, yet more preferably at least 0.85, even more preferably at least 0.9, most preferably at least 0.95, and in particular at least 1.0;

- at most 1.35, preferably at most 1.3, more preferably at most 1.25, still more preferably at most 1.2, yet more preferably at most 1.15, even more preferably at most 1.1, most preferably at most 1.05, and in particular at most 1.0; and/or

- within the range of from 1.5 : 1.0 to 1.0: 1.5, preferably from 1.4: 1.0 to 1.0: 1.4, more preferably from 1.3 : 1.0 to 1.0: 1.3, still more preferably from 1.2: 1.0 to 1.0: 1.2, and yet more preferably from 1.1 : 1.0 to 1.0: 1.1.

[0100] In other preferred embodiments, the carboxylic acid or carboxylic acid anhydride is a dicarbox- ylic acid; preferably an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid; more preferably malic acid, malonic acid, adipic acid, maleic acid, or phthalic acid; or a carboxylic acid anhydride of any of the foregoing. Maleic acid or maleic acid anhydride is particularly preferred.

[0101] In these preferred embodiments, the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is

- at least 1.65, preferably at least 1.7, more preferably at least 1.75, still more preferably at least 1.8, yet more preferably at least 1.85, even more preferably at least 1.9, most preferably at least 1.95, and in particular at least 2.0;

- at most 2.35, preferably at most 2.3, more preferably at most 2.25, still more preferably at most 2.2, yet more preferably at most 2.15, even more preferably at most 2.1, most preferably at most 2.05, and in particular at most 2.0; and/or - within the range of from 2.5 : 1.0 to 2.0: 1.5, preferably from 2.4: 1.0 to 2.0: 1.4, more preferably from 2.3: 1.0 to 2.0: 1.3, still more preferably from 2.2: 1.0 to 2.0: 1.2, and yet more preferably from 2.1: 1.0 to 2.0:1.1.

[0102] In still other preferred embodiments, the carboxylic acid or carboxylic acid anhydride is a tri carboxylic acid; preferably an aliphatic tricarboxylic acid or an aromatic tricarboxylic acid; more pref erably citric acid; or a carboxylic acid anhydride of any of the foregoing.

[0103] In these preferred embodiments, the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is

- at least 2.65, preferably at least 2.7, more preferably at least 2.75, still more preferably at least 2.8, yet more preferably at least 2.85, even more preferably at least 2.9, most preferably at least 2.95, and in particular at least 3.0;

- at most 3.35, preferably at most 3.3, more preferably at most 3.25, still more preferably at most 3.2, yet more preferably at most 3.15, even more preferably at most 3.1, most preferably at most 3.05, and in particular at most 3.0; and/or

- within the range of from 3.5 : 1.0 to 3.0: 1.5, preferably from 3.4: 1.0 to 3.0: 1.4, more preferably from 3.3 : 1.0 to 3.0: 1.3, still more preferably from 3.3 : 1.0 to 3.0: 1.2, and yet more preferably from 3.1 : 1.0 to 3.0:1.1.

[0104] Preferably, the carboxylic acid or carboxylic acid anhydride is a hydroxy carboxylic acid; pref erably an aliphatic hydroxycarboxylic acid; more preferably a saturated aliphatic hydroxycarboxylic acid; still more preferably malic acid or citric acid; or a carboxylic acid anhydride of any of the forego ing.

[0105] Preferably, the carboxylic acid or carboxylic acid anhydride is a hydroxycarboxylic acid; pref erably an aromatic hydroxycarboxylic acid; more preferably salicylic acid or gallic acid; or a carboxylic acid anhydride of any of the foregoing.

[0106] Preferably, the carboxylic acid or carboxylic acid anhydride is a saturated aliphatic carboxylic acid; preferably a saturated aliphatic monocarboxylic acid or a saturated aliphatic dicarboxylic acid or a saturated aliphatic tricarboxylic acid; more preferably citric acid, malic acid, heptanoic acid, malonic acid, or adipic acid; or a carboxylic acid anhydride of any of the foregoing.

[0107] Preferably, the carboxylic acid or carboxylic acid anhydride is an unsaturated aliphatic carbox ylic acid; preferably an unsaturated aliphatic monocarboxylic acid or an unsaturated aliphatic dicarboxylic acid; more preferably maleic acid; or a carboxylic acid anhydride of any of the foregoing. Maleic acid or maleic acid anhydride is particularly preferred.

[0108] Preferably, the carboxylic acid or carboxylic acid anhydride is an aromatic carboxylic acid; preferably an aromatic monocarboxylic acid or an aromatic dicarboxylic acid; more preferably phthalic acid, salicylic acid, gallic acid, or nicotinic acid; or a carboxylic acid anhydride of any of the foregoing.

[0109] Preferably, the carboxylic acid or carboxylic acid anhydride is a carboxylic acid selected from the group consisting of malic acid, heptanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, maleic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing. Maleic acid or maleic acid anhydride is particularly preferred.

[0110] Preferably, the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carbox ylic acid or carboxylic acid anhydride is stoichiometric.

[0111] Preferably, the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carbox ylic acid or carboxylic acid anhydride is

- at least 0.25, preferably at least 0.5, more preferably at least 0.75, still more preferably at least 1.0, yet more preferably at least 1.25, even more preferably at least 1.5, most preferably at least 1.75, and in particular at least 2.0;

- at most 2.75, preferably at most 2.5, more preferably at most 2.25, still more preferably at most 2.0, yet more preferably at most 1.75, even more preferably at most 1.5, most preferably at most 1.25, and in particular at most 1.0; and/or

- within the range of from 2.4: 1.0 to 2.0: 1.4, preferably from 2.3 : 1.0 to 2.0: 1.3, more preferably from 2.2:1.0 to 2.0: 1.2, still more preferably from 2.1:1.0 to 2.0: 1.1, yet more preferably from 1.4:1.0 to 1.0: 1.4, even more preferably from 1.3: 1.0 to 1.0: 1.3, most preferably from 1.2: 1.0 to 1.0: 1.2, and in particular from 1.1 : 1.0 to 1.0: 1.1.

[0112] Preferably, the stoichiometric ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is based on the deprotonatable groups of the carboxylic acid or carboxylic acid anhydride; preferably on the carboxylic groups of the carboxylic acid or carbox ylic acid anhydride.

[0113] In preferred embodiments, the weight content of the carboxylic acid or carboxylic acid anhy dride is - at least 2.5 wt.-%, preferably at least 4.0 wt.-%, more preferably at least 5.5 wt.-%, still more pref erably at least 7.0 wt.-%, yet more preferably at least 8.5 wt.-%, even more preferably at least 10 wt- %, most preferably at least 11.5 wt.-%, and in particular at least 13 wt.-%;

- at most 20.5 wt.-%, preferably at most 19 wt.-%, more preferably at most 17.5 wt.-%, still more preferably at most 16 wt.-%, yet more preferably at most 14.5 wt.-%, even more preferably at most 13 wt.-%, most preferably at most 11.5 wt.-%, and in particular at most 10 wt.-%; and/or

- within the range of from 6.3±4.0 wt.-%, preferably 6.3±3.5 wt.-%, more preferably 6.3±3.0 wt.-%, still more preferably 6.3±2.5 wt.-%, yet more preferably 6.3±2.0 wt.-%, even more preferably 6.3±1.5 wt.-%, most preferably 6.3±1.0 wt.-%, and in particular 6.3±0.5 wt.-%; in each case relative to the total weight of the solution.

[0114] In other preferred embodiments, the weight content of the carboxylic acid or carboxylic acid anhydride is

- at least 2.5 wt.-%, preferably at least 4.0 wt.-%, more preferably at least 5.5 wt.-%, still more pref erably at least 7.0 wt.-%, yet more preferably at least 8.5 wt.-%, even more preferably at least 10 wt- %, most preferably at least 11.5 wt.-%, and in particular at least 13 wt.-%;

- at most 38 wt.-%, preferably at most 34 wt.-%, more preferably at most 30 wt.-%, still more prefer ably at most 26 wt.-%, yet more preferably at most 22 wt.-%, even more preferably at most 18 wt.- %, most preferably at most 14 wt.-%, and in particular at most 10 wt.-%; and/or

- within the range of from 17.5±15 wt.-%, preferably 15±12.5 wt.-%, more preferably 12.5±10 wt.-%, still more preferably 12.5±7.5 wt.-%, yet more preferably 10±7.5 wt.-%, even more preferably 10±5.0 wt.-%, most preferably 7.5±5.0 wt.-%, and in particular 7.5±2.5 wt.-%; in each case relative to the total weight of the solution.

[0115] Preferably, the carboxylic acid or carboxylic acid anhydride is soluble, freely soluble or very soluble in the non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols (at 23 °C), whereas 10 to 30 mL volume of water are needed in order to dissolve a soluble carboxylic acid or carboxylic acid anhydride, 1 to 10 mL volume of water are needed in order to dissolve a freely soluble carboxylic acid or carboxylic acid anhydride, and less than 1 mL volume of water are needed in order to dissolve a very soluble carboxylic acid or carboxylic acid anhydride.

[0116] The solution according to the invention may contain one or more non-aqueous solvent. Prefer ably, the solution according to the invention contains a single non-aqueous solvent. [0117] Preferably, the non-aqueous solvent selected from polyalkylene glycols, preferably polyeth ylene glycols according to the invention is selected such that the carboxylic acid or carboxylic acid anhydride does not react with the pyrazole or agriculturally acceptable salt thereof by of a Michael addition. In particular, no covalent addition product of the carboxylic acid or carboxylic acid anhydride is formed with the pyrazole or agriculturally acceptable salt thereof.

[0118] The non-aqueous solvent is preferably a polyalkylene glycol.

[0119] In preferred embodiments, the non-aqueous solvent is a polyethylene glycol (PEG), preferably selected from the group consisting of PEG 100, PEG 200, PEG 300, PEG 400, PEG 500, PEG 600, PEG 1000, PEG 1500, and mixtures thereof; preferably PEG 200.

[0120] In preferred embodiments, the non-aqueous solvent is a polypropylene glycol (PPG), preferably selected from the group consisting of PPG 200, PPG 400, PPG 600, PPG 1000, and mixtures thereof.

[0121] In preferred embodiments, the non-aqueous solvent comprises or essentially consists of a mix ture of a polyethylene glycol (PEG) and a polypropylene glycol (PPG).

[0122] In preferred embodiments, the non-aqueous solvent is polyalkylene glycol, preferably polyeth ylene glycol with an average molecular weight of

- at least 100 g/mol, preferably at least 200 g/mol, more preferably at least 300 g/mol, still more pref erably at least 400 g/mol, yet more preferably at least 600 g/mol, even more preferably at least 800 g/mol, and most preferably at least 1000 g/mol;

- at most 2000 g/mol, preferably at most 1500 g/mol, more preferably at most 1000 g/mol, still more preferably at most 800 g/mol, yet more preferably at most 600 g/mol, even more preferably at most 400 g/mol, most preferably at most 300 g/mol, and in particular at most 200 g/mol; and/or

- within the range of from 600±400 g/mol, preferably 500±400 g/mol, more preferably 500±300 g/mol, still more preferably 400±300 g/mol, yet more preferably 400±200 g/mol, even more preferably 300±200 g/mol, most preferably 300±100 g/mol, and in particular 200±100 g/mol.

[0123] Preferably, the viscosity of the non-aqueous solvent selected from polyalkylene glycols, prefer ably polyethylene glycols is

- at least 25 mPa s, preferably at least 30 mPa s, more preferably at least 35 mPa s, still more prefer ably at least 40 mPa s, yet more preferably at least 45 mPa s, even more preferably at least 50 mPa s, most preferably at least 55 mPa s, and in particular at least 60 mPa s; - at most 500 mPa s, preferably at most 400 mPa s, more preferably at most 300 mPa s, still more preferably at most 200 mPa s, yet more preferably at most 100 mPa s, even more preferably at most 80 mPa s, most preferably at most 70 mPa s, and in particular at most 60 mPa s; and/or

- within the range of from 600±400 mPa s, preferably 500±400 mPa s, more preferably 500±300 mPa s, still more preferably 400±300 mPa s, yet more preferably 400±200 mPa s, even more pref erably 300±200 mPa s, most preferably 300±100 mPa s, and in particular 200±100 mPa s.

[0124] Preferably, the viscosity is determined at 20°C, preferably in accordance with ASTM D 2196.

[0125] In preferred embodiments, the weight content of the non-aqueous solvent selected from poly- alkylene glycols, preferably polyethylene glycols is

- at least 35 wt.-%, preferably at least 40 wt.-%, more preferably at least 45 wt.-%, still more preferably at least 50 wt.-%, yet more preferably at least 55 wt.-%, even more preferably at least 60 wt.-%, most preferably at least 65 wt.-%, and in particular at least 70 wt.-%;

- at most 85 wt.-%, preferably at most 80 wt.-%, more preferably at most 75 wt.-%, still more prefer ably at most 70 wt.-%, yet more preferably at most 65 wt.-%, even more preferably at most 60 wt.- %, most preferably at most 55 wt.-%, and in particular at most 50 wt.-%; and/or

- within the range of from 60±24 wt.-%, preferably 60±22 wt.-%, more preferably 60±20 wt.-%, still more preferably 60±18 wt.-%, yet more preferably 60±16 wt.-%, even more preferably 60±14 wt- %, most preferably 60±12 wt.-%, and in particular 60±10 wt.-%; in each case relative to the total weight of the solution.

[0126] In other preferred embodiments, the weight content of the non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is

- at least 20 wt.-%, preferably at least 25 wt.-%, more preferably at least 30 wt.-%, still more preferably at least 35 wt.-%, yet more preferably at least 40 wt.-%, even more preferably at least 45 wt.-%, most preferably at least 50 wt.-%, and in particular at least 55 wt.-%;

- at most 65 wt.-%, preferably at most 60 wt.-%, more preferably at most 55 wt.-%, still more prefer ably at most 50 wt.-%, yet more preferably at most 45 wt.-%, even more preferably at most 40 wt- %, most preferably at most 35 wt.-%, and in particular at most 30 wt.-%; and/or

- within the range of from 42±24 wt.-%, preferably 42±22 wt.-%, more preferably 42±20 wt.-%, still more preferably 42±18 wt.-%, yet more preferably 42±16 wt.-%, even more preferably 42±14 wt- %, most preferably 42±12 wt.-%, and in particular 42±10 wt.-%; in each case relative to the total weight of the solution. [0127] Preferably, the solution according to the invention does not comprise a solvent selected from the group consisting of methanol, dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyla- cetamide (DMA), and N-methyl-2-pyrrolidone (NMP).

[0128] Preferably, the solution according to the invention does not comprise N-methyl-2-pyrrolidone, preferably no pyrrolidone at all.

[0129] Preferably, the non-aqueous solvent selected from polyalkylene glycols, preferably polyeth ylene glycols is non-toxic.

[0130] Preferably, the non-aqueous solvent selected from polyalkylene glycols, preferably polyeth ylene glycols is non-flammable.

[0131] Preferably, the tracer is a dye .

[0132] In preferred embodiments, the weight content of the tracer is

- at least 0.1 wt.-%, preferably at least 0.2 wt.-%, more preferably at least 0.5 wt.-%, still more pref erably at least 1.0 wt.-%, yet more preferably at least 1.5 wt.-%, even more preferably at least 2.0 wt.-%, most preferably at least 2.5 wt.-%, and in particular at least 3.0 wt.-%;

- at most 4.0 wt.-%, preferably at most 3.5 wt.-%, more preferably at most 3.0 wt.-%, still more pref erably at most 2.5 wt.-%, yet more preferably at most 2.0 wt.-%, even more preferably at most 1.5 wt.-%, most preferably at most 1.0 wt.-%, and in particular at most 0.5 wt.-%; and/or

- within the range of from 2.0±1.5 wt.-%, preferably 1.5±1.0 wt.-%, more preferably 1.5±0.5 wt.-%, still more preferably 1.5±0.2 wt.-%, yet more preferably 1.0±0.5 wt.-%, even more preferably 1.0±0.2 wt.-%, most preferably 0.5±0.4 wt.-%, and in particular 0.5±0.2 wt.-%; in each case relative to the total weight of the solution.

[0133] Preferably, the solution according to the invention does not contain salts of alkali metals or alkaline earth metals. Preferably, the solution according to the invention does not contain any cations of alkali metals or alkaline earth metals.

[0134] In preferred embodiments, the solution according to the invention comprises or essentially con sists of

(i) 3,4-dimethylpyrazole (DMP) or an agriculturally acceptable salt thereof;

(ii) N-(n-butyl)thiophosphoric triamide (NBPT); (iii) optionally, a carboxylic acid selected from the group consisting of citric acid, malic acid, hep- tanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, ma leic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; maleic acid or maleic acid anhydride is particularly preferred;

(iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; and

(v) optionally a tracer; preferably a dye; in each case relative to the total weight of the solution.

[0135] In other preferred embodiments, the solution according to the invention comprises or essentially consists of

(i) 3,4-dimethylpyrazole (DMP) or an agriculturally acceptable salt thereof, preferably with a total weight content within the range of 7.5±2.5 wt.-%;

(ii) N-(n-butyl)thiophosphoric triamide (NBPT), preferably with a total weight content within the range of 25±5.0 wt.-%;

(iii) optionally, a carboxylic acid selected from the group consisting of citric acid, malic acid, hep- tanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, ma leic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; maleic acid or maleic acid anhydride is particularly preferred;

[0136] In still other preferred embodiments, the solution according to the invention comprises or es sentially consists of

(iii) optionally, a carboxylic acid selected from the group consisting of citric acid, malic acid, hep- tanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, ma leic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; maleic acid or maleic acid anhydride is particularly preferred; (iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; pref erably with a total weight content within the range of 60±10 wt.-%; and

[0137] In still other preferred embodiments, the solution according to the invention comprises or es sentially consists of

(iii) a carboxylic acid selected from the group consisting of heptanoic acid, salicylic acid, gallic acid, nicotinic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; preferably wherein the molar ratio of the DMP or agriculturally acceptable salt thereof to the carboxylic acid is within the range of from 1.1 : 1.0 to 1.0: 1.1 ;

(iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; pref erably with a total weight content within the range of 60±10 wt.-%; and

[0138] In still other preferred embodiments, the solution according to the invention comprises or es sentially consists of

(iii) a carboxylic acid selected from the group consisting of malic acid, malonic acid, adipic acid, maleic acid, phthalic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; preferably wherein the molar ratio of the DMP or agriculturally acceptable salt thereof to the carboxylic acid is within the range of from 2.1: 1.0 to 2.0: 1.1; maleic acid is particularly preferred;

(iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; pref erably with a total weight content within the range of 60±10 wt.-%; and (v) optionally a tracer; preferably a dye; in each case relative to the total weight of the solution.

[0139] In other preferred embodiments, the solution according to the invention comprises or essentially consists of

(i) 3,4-dimethylpyrazole (DMP) or an agriculturally acceptable salt thereof, preferably with a total weight content within the range of 17.5±2.5 wt.-%;

(iii) optionally, a carboxylic acid selected from the group consisting of citric acid, malic acid, hep- tanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, ma leic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; maleic acid is particularly preferred;

[0140] In still other preferred embodiments, the solution according to the invention comprises or es sentially consists of

(iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; pref erably with a total weight content within the range of 42±16 wt.-%; and

(v) optionally a tracer; preferably a dye; in each case relative to the total weight of the solution. [0141] In still other preferred embodiments, the solution according to the invention comprises or es sentially consists of

[0142] In still other preferred embodiments, the solution according to the invention comprises or es sentially consists of

(iii) a carboxylic acid selected from the group consisting of malic acid, malonic acid, adipic acid, maleic acid, phthalic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; preferably wherein the molar ratio of the DMP or agriculturally acceptable salt thereof to the carboxylic acid is within the range of from 2.1: 1.0 to 2.0: 1.1; maleic acid or maleic acid anhydride is particularly preferred;

[0143] In still preferred embodiments, the solution according to the invention essentially consists of (i) 3,4-dimethylpyrazole (DMP) or an agriculturally acceptable salt thereof; preferably with a total weight content of at least 2.0 wt.-%, more preferably at least 6.0 wt.-%;

(ii) N-(n-butyl)thiophosphoric triamide (NBPT), preferably with a total weight content of at least 10 wt.-%, more preferably at least 15 wt.-%;

(iii) optionally, a carboxylic acid or carboxylic acid anhydride; preferably wherein the molar ratio of the DMP or agriculturally acceptable salt thereof to the carboxylic acid is within the range of from 2.1: 1.0 to 1.0:1.1;

(iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; pref erably with a total weight content of at least 25 wt.-%; more preferably at least 30 wt.-%; and

[0144] Another aspect of the inventio relates to a process for preparing of a fertilizer composition, the process comprising the steps of:

(a) providing a solution according to the invention (fertilizer additive);

(b) providing a fertilizer; preferably a solid fertilizer; and

(c) applying the solution provided in step (a) to the fertilizer provided in step (b); preferably coating and/or impregnating the fertilizer provided in step (b) with the solution provided in step (a); preferably wherein the fertilizer provided in step (b) is in the form of granules, prills, pellets, pastilles, or a compounded form; more preferably prills.

[0145] The fertilizer preferably comprises or essentially consists of

(i) nitrogen fertilizers; preferably calcium nitrate, sodium nitrate, Chile salpeter, ammonium nitrate, calcium ammonium nitrate, ammonium sulfate nitrate, magnesium ammonium nitrate, ammonium sulfate, ammonium chloride, urea, calcium cyanamide, dicyandiamide, or mixtures thereof;

(ii) phosphate fertilizers; preferably basic slag (Thomas phosphate), superphosphate, triple superphos phate, partly digested phosphate rock, soft phosphate rock, dicalcium phosphate, thermal (fused) phosphate, aluminum calcium phosphate, or mixtures thereof;

(iii) potassium fertilizers; preferably potash ore, beneficiated potash ore, potassium chloride, potassium chloride with magnesium, potassium sulfate, potassium sulfate with magnesium; or

(iv) lime fertilizers;

(v) magnesium fertilizers; preferably kieserite; or

(vi) mixtures thereof; preferably NP fertilizers, NK fertilizers, PK fertilizers, or NPK fertilizers. [0146] Another aspect of the invention relates to a fertilizer additive comprising or consisting of the solution according to the invention.

[0147] Another aspect of the invention relates to a fertilizer composition comprising a fertilizer and the solution according to the invention; preferably wherein the fertilizer is a solid coated and/or impregnated with the solution according to the invention; preferably wherein the fertilizer is in the form of granules, prills, pellets, pastilles, or a compounded form; more preferably prills.

[0148] Another aspect of the invention relates to a use of a solution according to the invention as ferti lizer additive.

[0149] Another aspect of the invention relates to a use of a solution according to the invention for reducing nitrification.

[0150] Another aspect of the invention relates to a method for reducing nitrification comprising the step of applying a solution according to the invention to soil or a plant.

[0151] Another aspect of the invention relates to a method for reducing nitrification comprising the steps of

(a) adding a solution according to the invention to a fertilizer thereby obtaining a fertilizer composi tion; and

(b) applying the fertilizer composition to soil or a plant.

[0152] The following examples further illustrate the invention but are not to be construed as limiting its scope.

Example 1:

[0153] The following non-aqueous solutions comprising N-(n-butyl)thiophosphoric triamide (NBPT), 3,4-dimethylpyrazole (DMP) and polyethylene glycol (PEG) 200 were prepared by mixing the compo nents at room temperature:

Example 2:

[0154] The following non-aqueous solutions comprising N-(n-butyl)thiophosphoric triamide (NBPT), 3,4-dimethylpyrazole (DMP) and polyethylene glycol (PEG) 200 were prepared by mixing the compo nents at room temperature:

Example 3:

[0155] The following non-aqueous solutions comprising N-(n-butyl)thiophosphoric triamide (NBPT), 3,4-dimethylpyrazole (DMP) and polyethylene glycol (PEG) 200 were prepared by mixing the compo nents at room temperature:

Example 4:

[0156] Various solutions comprising 3,4-dimethylpyrazole (DMP) and N-(n-butyl)thiophosphoric tri amide (NBPT) in polyethylene glycol 200 (PEG 200), propylene glycol, or butylene glycol were pre pared (Examples 4-3 to 4-8). Examples 4-4, 4-6 and 4-8 additionally contained 50 wt.-% of maleic acid anhydride (MAA), relative to the amount of DMP. Solutions 4-1 to 4-4 were stored at 40°C for 5 days. Solutions 4-5 to 4-8 were stored at 40°C for 2 days. As a reference, undissolved 3,4-dimethylpyrazole phosphate (DMPP) and DMP were also stored at 40°C for 5 days (Examples 4-1 and 4-2). After storage, the remaining amount of DMP or DMPP was determined, relative to the total amount of DMP or DMPP before storage. The composition of the solutions and the amount of remaining DMP or DMPP relative to the amount of DMP or DMPP before storage is compiled in the table here below:

[0157] As demonstrated by the above comparative data, evaporation of DMP is reduced by dissolving DMP in a suitable solvent. In particular, PEG 200 provides similar residual amounts of DMP after 5 days at 40°C as propylene glycol and butylene glycol after only 2 days at 40°C. Further, evaporation of DMP is reduced and storage stability of the solution is increased by the addition of maleic acid anhy dride. Example 5:

[0158] Solutions comprising 25 wt.-% of N-(n-butyl)thiophosphoric triamide (NBPT), relative to the total weight of the solution, and from 5.0 to 27.5 wt.-% of 3,4-dimethylpyrazole (DMP), relative to the total weight of the solution, were prepared. Examples 5-7 to 5-12 additionally contained 50 wt.-% of maleic acid anhydride (MAA), relative to the amount of DMP. All solutions were stored at 0°C for 5 days and stability regarding crystallization was investigated each day. The results are compiled in the table here below:

[0159] As demonstrated by the above comparative data, the addition of maleic acid anhydride increases the stability of the solutions even at comparatively low temperatures and high DMP contents.

Example 6:

[0160] Solutions of 3,4-dimethylpyrazole (DMP) and N-(n-butyl)thiophosphoric triamide (NBPT) in polyethylene glycol 200 (PEG 200) with malic acid, citric acid, phthalic acid or maleic acid were pre pared (Examples 6-2 to 6-5). Further, a reference solution containing no acid was prepared (Example 6- 1). All solutions were stored at room temperature (25 °C) for 5 days. After storage, the content of DMP and NBPT of each solution, in each case relative to the total weight of the solution, was determined. The results are compiled in the table here below:

[0161] As demonstrated by the above comparative data, loss of NBPT is reduced with maleic acid anhydride compared to malic acid, citric acid and phthalic acid.

[0162] The solutions of Examples 6-1 to 6-5 were also applied on urea-fertilizer (Examples 6-7 to 6- 12). As a reference, an aqueous solution of DMPP and a solution of NBPT in PEG 200 were subse quently applied onto urea-fertilizer (Example 6-6). The fertilizer compositions were stored at room tem perature (25 °C) for 4 weeks. After storage, the content of DMP and NBPT of each composition, in each case relative to the total weight of the fertilizer composition, was determined. The results are compiled in the table here below:

[0163] As demonstrated by the above comparative data, the subsequent application of an aqueous so lution of DMP and a solution of NBPT in PEG 200 onto urea-fertilizer leads to a fertilizer composition with nearly no NBPT, i.e. wherein nearly the total amount of NBPT is hydrolyzed. In contrast, applica tion of co-formulations comprising DMP and NBPT in PEG 200 and optionally maleic acid anhydride, malic acid, citric acid or phthalic acid leads to fertilizer compositions with an increased amount of DMP and a desired, i.e. significantly increased, amount of NBPT. Further, loss of NBPT is reduced with ma leic acid anhydride compared to malic acid, citric acid and phthalic acid.

Claims

Patent claims:

1. An essentially non-aqueous solution comprising or essentially consisting of

(i) a pyrazole of general formula (I)

wherein

R1 means -H, -Ci-e -alkyl, or -Ci-e-alkyl-OH; preferably -H;

R3 and R4 independently of one another mean -H, -CY_r, -alkyl. -Ci-e-alkyl-OH, -NFb, - F, -Cl, or -Br; preferably -CFF; or an agriculturally acceptable salt thereof; preferably 3,4-dimethylpyrazole or an agricul turally acceptable salt thereof;

(ii) a thiophosphoric triamide of general formula (II)

wherein

R5 means -H, -Ci-₂₀-alkyl, -C_3-20-cycloalkyl, -C_3-io-aryl, -di(Ci-₂o-alkyl)aminocar- bonyl, -di(C_3-20-cycloalkyl)aminocarbonyl, -di(C_3-io-aryl)aminocarbonyl; prefera bly -H;

R6 means -H, -Ci-₂₀-alkyl, -C_3-20-cycloalkyl, -C_3-io-aryl, -di(Ci-₂o-alkyl)aminocar- bonyl, -di(C_3-20-cycloalkyl)aminocarbonyl, -di(C_3-io-aryl)aminocarbonyl; prefera bly -Ci-₂₀-alkyl; preferably N-(n-butyl)thiophosphoric triamide;

(v) optionally, a tracer.

2. The solution according to claim 1, which has a water content of at most 5 wt.-%, preferably at most 2.5 wt.-%, more preferably at most 1.0 wt.-%, still more preferably at most 0.9 wt.-%, yet more preferably at most 0.8 wt.-%, even more preferably at most 0.7 wt.-%, most preferably at most 0.6 wt.-%, and in particular at most 0.5 wt.-%; preferably comprises no water at all.

3. The solution according to claim 1 or 2, wherein the pyrazole is selected from the group consisting of pyrazole, 3,4-dimethylpyrazole, 3,5-dimethylpyrazole, 4-chloro-3-methylpyrazole, 5-chloro- 1,3-dimethylpyrazole, 5-amino-l,3-dimethylpyrazole, 3, 5 -dimethylpyrazole-1 -methanol, 1-allyl- 3,5-dimethylpyrazole, l-(2-hydroxyethyl)-pyrazole, 1 -methyl- l//-pyrazole-4-carboxaldehyde. l//-pyrazole-3-carbaldehyde. l//-pyrazole-5-carbaldehyde. li/-pyrazole-3 -carboxylic acid, 2 H- pyrazole-3 -carboxylic acid, 1,5 -dimethyl- li/-pyrazole-4-carboxylic acid, 4-bromo-l,3-dimethyl- li/-pyrazole-5 -carboxylic acid, li/-pyrazole-4, 5-diamine, or an agriculturally acceptable salt thereof.

4. The solution according to any of the preceding claims, wherein the pyrazole is 3,4-dimethylpyra zole (DMP) or an agriculturally acceptable salt thereof.

5. The solution according to any of the preceding claims, wherein the pyrazole is at least partially present in the non-salt form.

6. The solution according to any of the preceding claims, wherein the pyrazole is at least partially present in form of an agriculturally acceptable salt; preferably not 3,4-dimethylpyrazole phos phate.

7. The solution according to any of the preceding claims, wherein the pyrazole is at least partially present in form of an agriculturally acceptable acid addition salt with the carboxylic acid or car boxylic acid anhydride.

8. The solution according to any of the preceding claims, wherein the pyrazole is present in the non salt form and/or in form of an agriculturally acceptable acid addition salt with the optionally pre sent carboxylic acid or carboxylic acid anhydride.

9. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 2.0 wt.-%, preferably at least 2.5 wt.-%, more preferably at least 3.0 wt.-%, still more preferably at least 3.5 wt.-%.

10. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 4.0 wt.-%, preferably at least 4.5 wt.-%, more preferably at least 5.0 wt.-%, still more preferably at least 5.5 wt.-%, yet more preferably at least 6.0 wt.-%, even more preferably at least 6.5 wt.-%, most preferably at least 7.0 wt.-%, and in particular at least 7.5 wt.-%.

11. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is at most 11 wt.-%, preferably at most 10.5 wt.-%, more preferably at most 10 wt.-%, still more preferably at most 9.5 wt.-%, yet more preferably at most 9.0 wt.-%, even more preferably at most 8.5 wt.-%, most preferably at most 8.0 wt.-%, and in particular at most 7.5 wt.-%.

12. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is within the range of 7.5±6.0 wt.-%, preferably 7.5±5.5 wt.-%, more preferably 7.5±5.0 wt.-%, still more preferably 7.5±4.5 wt.-%, yet more preferably 7.5±4.0 wt.-%, even more preferably 7.5±3.5 wt.-%, most preferably 7.5±3.0 wt.-%, and in par ticular 7.5±2.5 wt.-%; in each case relative to the total weight of the solution.

13. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 8.0 wt.-%, preferably at least 9.0 wt.-%, more preferably at least 10 wt.-%, still more preferably at least 11 wt.-%, yet more preferably at least 12 wt.-%, even more preferably at least 12.5 wt.-%, most 1 preferably at least 13 wt.-%, and in particular at least 13.5 wt.-%.

14. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 14.0 wt.-%, preferably at least 14.5 wt.-%, more preferably at least 15.0 wt.-%, still more preferably at least 15.5 wt.-%, yet more preferably at least 16.0 wt.-%, even more preferably at least 16.5 wt.-%, most lpreferably at least 17.0 wt.-%, and in particular at least 17.5 wt.-%.

15. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is at most 21 wt.-%, preferably at most 20.5 wt.-%, more preferably at most 20 wt.-%, still more preferably at most 19.5 wt.-%, yet more preferably at most

19.0 wt.-%, even more preferably at most 18.5 wt.-%, most lpreferably at most 18.0 wt.-%, and in particular at most 17.5 wt.-%.

16. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is within the range of 17.5±6.0 wt.-%, preferably 17.5±5.5 wt.-%, more preferably 17.5±5.0 wt.-%, still more preferably 17.5±4.5 wt.-%, yet more preferably 17.5±4.0 wt.-%, even more preferably 17.5±3.5 wt.-%, most lpreferably 17.5±3.0 wt.-%, and in particular 17.5±2.5 wt.-%; in each case relative to the total weight of the solution.

17. The solution according to any of the preceding claims, wherein the weight content of the pyrazole or agriculturally acceptable salt thereof is at least 5.0 wt.-%, or at least 10 wt.-%, or at least 15 wt.-%, or at least 20 wt.-%, or at least 25 wt.-%, or at least 30 wt.-%, or at least 35 wt.-%, or at least 40 wt.-%, or at least 45 wt.-%, or at least 50 wt.-%, or at least 55 wt.-%, or at least 60 wt.- %, relative to the total weight of the solution.

18. The solution according to any of the preceding claims, wherein essentially the total amount, more preferably all of the pyrazole or agriculturally acceptable salt thereof contained in the solution is completely solved.

19. The solution according to any of the preceding claims, wherein the pyrazole or agriculturally acceptable salt thereof is a nitrification inhibitor.

20. The solution according to any of the preceding claims, wherein the thiophosphoric triamide is selected from the group consisting of N-(n-butyl)thiophosphoric triamide, N-(n-propyl)thiophos- phoric triamide, N-(cyclohexyl)thiophosphoric triamide and N-(2-nitrophenyl)thiophosphoric tri amide.

21. The solution according to any of the preceding claims, wherein R5 represents -H.

22. The solution according to any of the preceding claims, wherein R6 represents -Ci-20-alkyl.

23. The solution according to any of the preceding claims, wherein R6 represents -n-butyl.

24. The solution according to any of the preceding claims, wherein the thiophosphoric triamide is N-

(n-butyl)thiophosphoric triamide (NBPT).

25. The solution according to any of the preceding claims, wherein the weight content of the thio- phosphoric triamide is at least 7.5 wt.-%, preferably at least 10 wt.-%, more preferably at least 12.5 wt.-%, still more preferably at least 15 wt.-%, yet more preferably at least 17.5 wt.-%, even more preferably at least 20 wt.-%, most preferably at least 22.5 wt.-%, and in particular at least

25 wt.-%

26. The solution according to any of the preceding claims, wherein the weight content of the thio- phosphoric triamide is at most 42.5 wt.-%, preferably at most 40 wt.-%, more preferably at most 37.5 wt.-%, still more preferably at most 35 wt.-%, yet more preferably at most 32.5 wt.-%, even more preferably at most 30 wt.-%, most preferably at most 27.5 wt.-%, and in particular at most 25 wt.-%.

27. The solution according to any of the preceding claims, wherein the weight content of the thio- phosphoric triamide is within the range of 25±12 wt.-%, preferably 25±11 wt.-%, more preferably 25±10 wt.-%, still more preferably 25±9.0 wt.-%, yet more preferably 25±8.0 wt.-%, even more preferably 25±7.0 wt.-%, most preferably 25±6.0 wt.-%, and in particular 25±5.0 wt.-%; in each case relative to the total weight of the solution.

28. The solution according to any of the preceding claims, wherein essentially the total amount, more preferably all of the thiophosphoric triamide contained in the solution is completely solved.

29. The solution according to any of the preceding claims, wherein the weight content of the thio phosphoric triamide is greater than the weight content of the pyrazole or agriculturally acceptable salt thereof.

30. The solution according to any of the preceding claims, wherein the relative weight ratio of the pyrazole or agriculturally acceptable salt thereof to the thiophosphoric triamide is at least 0.16, preferably at least 0.18, more preferably at least 0.20, still more preferably at least 0.22, yet more preferably at least 0.24, even more preferably at least 0.26, most preferably at least 0.28, and in particular at least 0.30.

31. The solution according to any of the preceding claims, wherein the relative weight ratio of the pyrazole or agriculturally acceptable salt thereof to the thiophosphoric triamide is at most 0.70, preferably at most 0.65, more preferably at most 0.60, still more preferably at most 0.55, yet more preferably at most 0.49, even more preferably at most 0.46, most preferably at most 0.43, and in particular at most 0.40.

32. The solution according to any of the preceding claims, wherein the relative weight ratio of the pyrazole or agriculturally acceptable salt thereof to the thiophosphoric triamide is within the range of from 1 :7 to 1: 1.1, preferably from 1 :6.5 to 1 : 1.3, more preferably from 1 :6 to 1: 1.5, still more preferably from 1:5.5 to 1: 1.7, yet more preferably from 1:5 to 1: 1.9, even more preferably from 1:4.5 to 1:2.1, most preferably from 1:4 to 1:2.3, and in particular from 1:3.5 to 1:2.5.

33. The solution according to any of the preceding claims, wherein the thiophosphoric triamide is a urease inhibitor.

34. The solution according to any of the preceding claims, wherein the carboxylic acid is in its non salt form, i.e. in its fully protonated state.

35. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a carboxylic acid.

36. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is an aliphatic carboxylic acid or an aromatic carboxylic acid; or a carboxylic acid anhydride of any of the foregoing; preferably a saturated aliphatic carboxylic acid, an unsaturated aliphatic carboxylic acid or an aromatic carboxylic acid; or a carboxylic acid anhydride of any of the foregoing.

37. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a saturated aliphatic carboxylic acid or an aromatic carboxylic acid; or a car boxylic acid anhydride of any of the foregoing.

38. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a monocarboxylic acid; preferably an aliphatic monocarboxylic acid or an aro matic monocarboxylic acid; more preferably heptanoic acid, salicylic acid, gallic acid, or nicotinic acid; or a carboxylic acid anhydride of any of the foregoing; preferably maleic acid anhydride.

39. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is at least 0.65, preferably at least 0.7, more preferably at least 0.75, still more preferably at least 0.8, yet more preferably at least 0.85, even more preferably at least 0.9, most preferably at least 0.95, and in particular at least 1.0.

40. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is at most

1.35, preferably at most 1.3, more preferably at most 1.25, still more preferably at most 1.2, yet more preferably at most 1.15, even more preferably at most 1.1, most preferably at most 1.05 , and in particular at most 1.0.

41. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is within the range of from 1.5: 1.0 to 1.0: 1.5, preferably from 1.4: 1.0 to 1.0: 1.4, more preferably from 1.3: 1.0 to 1.0: 1.3, still more preferably from 1.2: 1.0 to 1.0: 1.2, and yet more preferably from 1.1: 1.0 to 1.0: 1.1.

42. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a dicarboxylic acid; preferably an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid; more preferably malic acid, malonic acid, adipic acid, maleic acid, or phthalic acid; or a carboxylic acid anhydride of any of the foregoing.

43. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is at least 1.65, preferably at least 1.7, more preferably at least 1.75, still more preferably at least 1.8, yet more preferably at least 1.85, even more preferably at least 1.9, most preferably at least 1.95, and in particular at least 2.0.

44. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is at most

2.35, preferably at most 2.3, more preferably at most 2.25, still more preferably at most 2.2, yet more preferably at most 2.15, even more preferably at most 2.1, most preferably at most 2.05, and in particular at most 2.0.

45. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is within the range of from 2.5: 1.0 to 2.0: 1.5, preferably from 2.4: 1.0 to 2.0: 1.4, more preferably from 2.3: 1.0 to 2.0: 1.3, still more preferably from 2.2: 1.0 to 2.0: 1.2, and yet more preferably from 24 : 1.0 to 2.0: 1.1.

46. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a tricarboxylic acid; preferably an aliphatic tricarboxylic acid or an aromatic tricarboxylic acid; more preferably citric acid; or a carboxylic acid anhydride of any of the fore going.

47. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a hydroxycarboxylic acid; preferably an aliphatic hydroxycarboxylic acid; more preferably a saturated aliphatic hydroxycarboxylic acid; still more preferably malic acid or citric acid; or a carboxylic acid anhydride of any of the foregoing.

48. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a hydroxycarboxylic acid; preferably an aromatic hydroxycarboxylic acid; more preferably salicylic acid or gallic acid; or a carboxylic acid anhydride of any of the foregoing.

49. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a saturated aliphatic carboxylic acid; preferably a saturated aliphatic monocar- boxylic acid or a saturated aliphatic dicarboxylic acid or a saturated aliphatic tricarboxylic acid; more preferably citric acid, malic acid, heptanoic acid, malonic acid, or adipic acid; or a carbox ylic acid anhydride of any of the foregoing.

50. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is an unsaturated aliphatic carboxylic acid; preferably an unsaturated aliphatic monocarboxylic acid or an unsaturated aliphatic dicarboxylic acid; more preferably maleic acid; or a carboxylic acid anhydride of any of the foregoing.

51. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is an aromatic carboxylic acid; preferably an aromatic monocarboxylic acid or an aromatic dicarboxylic acid; more preferably phthalic acid, salicylic acid, gallic acid, or nicotinic acid; or a carboxylic acid anhydride of any of the foregoing.

52. The solution according to any of the preceding claims, wherein the carboxylic acid or carboxylic acid anhydride is a carboxylic acid selected from the group consisting of citric acid, malic acid, heptanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, maleic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing.

53. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is stoi chiometric.

54. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is at least 0.25, preferably at least 0.5, more preferably at least 0.75, still more preferably at least 1.0, yet more preferably at least 1.25, even more preferably at least 1.5, most preferably at least 1.75, and in particular at least 2.0.

55. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is at most 2.75, preferably at most 2.5, more preferably at most 2.25, still more preferably at most 2.0, yet more preferably at most 1.75, even more preferably at most 1.5, most preferably at most 1.25, and in particular at most 1.0.

56. The solution according to any of the preceding claims, wherein the molar ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhydride is within the range of from 2.4: 1.0 to 2.0: 1.4, preferably from 2.3: 1.0 to 2.0: 1.3, more preferably from 2.2: 1.0 to 2.0: 1.2, still more preferably from 2.1 : 1.0 to 2.0: 1.1, yet more preferably from 1.4: 1.0 to 1.0: 1.4, even more preferably from 1.3: 1.0 to 1.0: 1.3, most preferably from 1.2: 1.0 to 1.0: 1.2, and in particular from 1.1 : 1.0 to 1.0: 1.1.

57. The solution according to any of the preceding claims, wherein the stoichiometric ratio of the pyrazole or agriculturally acceptable salt thereof to the carboxylic acid or carboxylic acid anhy dride is based on the deprotonatable groups of the carboxylic acid or carboxylic acid anhydride; preferably on the carboxylic groups of the carboxylic acid or carboxylic acid anhydride.

58. The solution according to any of the preceding claims, wherein the weight content of the carbox ylic acid or carboxylic acid anhydride is at least 2.5 wt.-%, preferably at least 4.0 wt.-%, more preferably at least 5.5 wt.-%, still more preferably at least 7.0 wt.-%, yet more preferably at least

8.5 wt.-%, even more preferably at least 10 wt.-%, most preferably at least 11.5 wt.-%, and in particular at least 13 wt.-%.

59. The solution according to any of the preceding claims, wherein the weight content of the carbox ylic acid or carboxylic acid anhydride is at most 20.5 wt.-%, preferably at most 19 wt.-%, more preferably at most 17.5 wt.-%, still more preferably at most 16 wt.-%, yet more preferably at most

14.5 wt.-%, even more preferably at most 13 wt.-%, most preferably at most 11.5 wt.-%, and in particular at most 10 wt.-%.

60. The solution according to any of the preceding claims, wherein the weight content of the carbox ylic acid or carboxylic acid anhydride is within the range of from 6.3±4.0 wt.-%, preferably 6.3±3.5 wt.-%, more preferably 6.3±3.0 wt.-%, still more preferably 6.3±2.5 wt.-%, yet more preferably 6.3±2.0 wt.-%, even more preferably 6.3±1.5 wt.-%, most preferably 6.3±1.0 wt.-%, and in particular 6.3±0.5 wt.-%; in each case relative to the total weight of the solution.

61. The solution according to any of the preceding claims, wherein the weight content of the carbox ylic acid or carboxylic acid anhydride is at least 2.5 wt.-%, preferably at least 4.0 wt.-%, more preferably at least 5.5 wt.-%, still more preferably at least 7.0 wt.-%, yet more preferably at least 8.5 wt.-%, even more preferably at least 10 wt.-%, most preferably at least 11.5 wt.-%, and in particular at least 13 wt.-%.

62. The solution according to any of the preceding claims, wherein the weight content of the carbox ylic acid or carboxylic acid anhydride is at most 38 wt.-%, preferably at most 34 wt.-%, more preferably at most 30 wt.-%, still more preferably at most 26 wt.-%, yet more preferably at most 22 wt.-%, even more preferably at most 18 wt.-%, most preferably at most 14 wt.-%, and in par ticular at most 10 wt.-%.

63. The solution according to any of the preceding claims, wherein the weight content of the carbox ylic acid or carboxylic acid anhydride is within the range of from 17.5±15 wt.-%, preferably 15±12.5 wt.-%, more preferably 12.5±10 wt.-%, still more preferably 12.5±7.5 wt.-%, yet more preferably 10±7.5 wt.-%, even more preferably 10±5.0 wt.-%, most preferably 7.5±5.0 wt.-%, and in particular 7.5±2.5 wt.-%; in each case relative to the total weight of the solution.

64. The solution according to any of the preceding claims, wherein the non-aqueous solvent is se lected from the group consisting of polyethylene glycols (PEG); preferably from PEG 100, PEG 200, PEG 300, PEG 400, PEG 500, PEG 600, PEG 1000, PEG 1500, and mixtures thereof; pref erably PEG 200.

65. The solution according to any of the preceding claims, wherein the non-aqueous solvent is se lected from the group consisting of polypropylene glycols (PPG); preferably from PPG 200, PPG 400, PPG 600, PPG 1000, and mixtures thereof; preferably PPG 200.

66. The solution according to any of the preceding claims, wherein the non-aqueous solvent is a pol- yalkylene glycol, preferably polyethylene glycol with an average molecular weight of at least 100 g/mol, preferably at least 200 g/mol, more preferably at least 300 g/mol, still more preferably at least 400 g/mol, yet more preferably at least 600 g/mol, even more preferably at least 800 g/mol, and most preferably at least 1000 g/mol.

67. The solution according to any of the preceding claims, wherein the non-aqueous solvent is a pol- yalkylene glycol, preferably polyethylene glycol with an average molecular weight of at most 2000 g/mol, preferably at most 1500 g/mol, more preferably at most 1000 g/mol, still more pref erably at most 800 g/mol, yet more preferably at most 600 g/mol, even more preferably at most 400 g/mol, most preferably at most 300 g/mol, and in particular at most 200 g/mol.

68. The solution according to any of the preceding claims, wherein the non-aqueous solvent is a pol- yalkylene glycol, preferably polyethylene glycol with an average molecular weight of within the range of from 600±400 g/mol, preferably 500±400 g/mol, more preferably 500±300 g/mol, still more preferably 400±300 g/mol, yet more preferably 400±200 g/mol, even more preferably 300±200 g/mol, most preferably 300±100 g/mol, and in particular 200±100 g/mol.

69. The solution according to any of the preceding claims, wherein the viscosity of the non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is at least 25 mPa· s, preferably at least 30 mPa s, more preferably at least 35 mPa s, still more preferably at least 40 mPa s, yet more preferably at least 45 mPa s, even more preferably at least 50 mPa s, most pref erably at least 55 mPa s, and in particular at least 60 mPa s.

70. The solution according to any of the preceding claims, wherein the viscosity of the non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is at most 500 mPa s, preferably at most 400 mPa s, more preferably at most 300 mPa s, still more preferably at most 200 mPa s, yet more preferably at most 100 mPa s, even more preferably at most 80 mPa s, most preferably at most 70 mPa s, and in particular at most 60 mPa s.

71. The solution according to any of the preceding claims, wherein the viscosity of the non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is within the range of from 600±400 mPa s, preferably 500±400 mPa s, more preferably 500±300 mPa s, still more preferably 400±300 mPa s, yet more preferably 400±200 mPa s, even more preferably 300±200 mPa s, most preferably 300±100 mPa s, and in particular 200±100 mPa s.

72. The solution according to any of the preceding claims, wherein the weight content of the non- aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is at least 25 wt.-%, preferably at least 30 wt.-%, more preferably at least 35 wt.-%, still more preferably at least 40 wt.-%, yet more preferably at least 45 wt.-%, even more preferably at least 50 wt.-%, most preferably at least 55 wt.-%, and in particular at least 60 wt.-%.

73. The solution according to any of the preceding claims, wherein the weight content of the non- aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is at most 85 wt.-%, preferably at most 80 wt.-%, more preferably at most 75 wt.-%, still more preferably at most 70 wt.-%, yet more preferably at most 65 wt.-%, even more preferably at most 60 wt.-%, most preferably at most 55 wt.-%, and in particular at most 50 wt.-%.

74. The solution according to any of the preceding claims, wherein the weight content of the non- aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is within the range of from 60±24 wt.-%, preferably 60±22 wt.-%, more preferably 60±20 wt.-%, still more preferably 60±18 wt.-%, yet more preferably 60±16 wt.-%, even more preferably 60±14 wt.-%, most preferably 60±12 wt.-%, and in particular 60±10 wt.-%; in each case relative to the total weight of the solution.

75. The solution according to any of the preceding claims, wherein the weight content of the non- aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is at least 35 wt.-%, preferably at least 40 wt.-%, more preferably at least 45 wt.-%, still more preferably at least 50 wt.-%, yet more preferably at least 55 wt.-%, even more preferably at least 60 wt.-%, most preferably at least 65 wt.-%, and in particular at least 70 wt.-%.

76. The solution according to any of the preceding claims, wherein the weight content of the non- aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is at most 65 wt.-%, preferably at most 60 wt.-%, more preferably at most 55 wt.-%, still more preferably at most 50 wt.-%, yet more preferably at most 45 wt.-%, even more preferably at most 40 wt.-%, most preferably at most 35 wt.-%, and in particular at most 30 wt.-%.

77. The solution according to any of the preceding claims, wherein the weight content of the non- aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is within the range of from 42±24 wt.-%, preferably 42±22 wt.-%, more preferably 42±20 wt.-%, still more preferably 42±18 wt.-%, yet more preferably 42±16 wt.-%, even more preferably 42±14 wt.-%, most preferably 42±12 wt.-%, and in particular 42±10 wt.-%; in each case relative to the total weight of the solution.

78. The solution according to any of the preceding claims, which does not comprise a solvent selected from the group consisting of methanol, dimethylsulfoxide, dimethylformamide, dimethylacetam- ide, and methylpyrrolidone.

79. The solution according to any of the preceding claims, which does not comprise N-methyl-2- pyrrolidone, preferably no pyrrolidone at all.

80. The solution according to any of the preceding claims, wherein the non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is non-toxic.

81. The solution according to any of the preceding claims, wherein the non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols is non-flammable.

82. The solution according to any of the preceding claims, wherein the tracer is a dye.

83. The solution according to any of the preceding claims, which does not contain salts of alkali metals or alkaline earth metals.

84. The solution according to any of the preceding claims, which comprises or essentially consists of

(i) 3,4-dimethylpyrazole (DMP) or an agriculturally acceptable salt thereof;

(ii) N-(n-butyl)thiophosphoric triamide (NBPT);

(iii) optionally, a carboxylic acid selected from the group consisting of citric acid, malic acid, heptanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, maleic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing;

85. The solution according to any of the preceding claims, which comprises or essentially consists of

(ii) N-(n-butyl)thiophosphoric triamide (NBPT), preferably with a total weight content within the range of 25±5.0 wt.-%; (iii) optionally, a carboxylic acid selected from the group consisting of citric acid, malic acid, heptanoic acid, malonic acid, adipic acid, phthalic acid, salicylic acid, gallic acid, nicotinic acid, maleic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing;

86. The solution according to any of the preceding claims, which comprises or essentially consists of

(iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; preferably with a total weight content within the range of 60±10 wt.-%; and

87. The solution according to any of the preceding claims, which comprises or essentially consists of

(iii) a carboxylic acid selected from the group consisting of heptanoic acid, salicylic acid, gallic acid, nicotinic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; preferably wherein the molar ratio of the DMP or agriculturally acceptable salt thereof to the carboxylic acid is within the range of from 1.1 : 1.0 to 1.0: 1.1 ; (iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; preferably with a total weight content within the range of 60±10 wt.-%; and

88. The solution according to any of the preceding claims, which comprises or essentially consists of

(iii) a carboxylic acid selected from the group consisting of malic acid, malonic acid, adipic acid, maleic acid, phthalic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; preferably wherein the molar ratio of the DMP or agriculturally acceptable salt thereof to the carboxylic acid is within the range of from 2.1 : 1.0 to 2.0: 1.1 ;

89. The solution according to any of the preceding claims, which comprises or essentially consists of

90. The solution according to any of the preceding claims, which comprises or essentially consists of

(iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; preferably with a total weight content within the range of 42±16 wt.-%; and

91. The solution according to any of the preceding claims, which comprises or essentially consists of

92. The solution according to any of the preceding claims, which comprises or essentially consists of

(ii) N-(n-butyl)thiophosphoric triamide (NBPT), preferably with a total weight content within the range of 25±5.0 wt.-%; (iii) a carboxylic acid selected from the group consisting of malic acid, malonic acid, adipic acid, maleic acid phthalic acid, and combinations thereof; or a carboxylic acid anhydride of any of the foregoing; preferably wherein the molar ratio of the DMP or agriculturally acceptable salt thereof to the carboxylic acid is within the range of from 2.1 : 1.0 to 2.0: 1.1 ;

93. The solution according to any of the preceding claims, which essentially consists of

(i) 3,4-dimethylpyrazole (DMP) or an agriculturally acceptable salt thereof; preferably with a total weight content of at least 2.0 wt.-%, more preferably at least 6.0 wt.-%;

(iii) optionally, a carboxylic acid or carboxylic acid anhydride; preferably wherein the molar ratio of the DMP or agriculturally acceptable salt thereof to the carboxylic acid is within the range of from 2.1: 1.0 to 1.0: 1.1;

(iv) a non-aqueous solvent selected from polyalkylene glycols, preferably polyethylene glycols; preferably with a total weight content of at least 25 wt.-%; more preferably at least 30 wt- %; and

94. A process for preparing a fertilizer composition, the process comprising the steps of:

(a) providing a solution according to any of the preceding claims;

(b) providing a fertilizer; preferably a solid fertilizer; preferably a solid fertilizer in the form of granules, prills, pellets, pastilles, or a compounded form; more preferably prills and

(c) applying the solution provided in step (a) to the fertilizer provided in step (b); preferably coating and/or impregnating the fertilizer provided in step (b) with the solution provided in step (a).

95. A fertilizer additive comprising or consisting of the solution according to any of claims 1 to 93.

96. A fertilizer composition comprising a fertilizer and a solution according to any of claims 1 to 93.

97. The fertilizer composition according to claim 96, wherein the fertilizer is a solid fertilizer that is coated and/or impregnated with the solution.

98. The fertilizer composition according to claim 96 or 97, wherein the fertilizer is in the form of granules, prills, pellets, pastilles, or a compounded form; more preferably prills.

99. The fertilizer composition according to any of claims 96 to 98, wherein the fertilizer comprises or essentially consists of

(i) nitrogen fertilizers; preferably calcium nitrate, sodium nitrate, Chile salpeter, ammonium ni trate, calcium ammonium nitrate, ammonium sulfate nitrate, magnesium ammonium nitrate, ammonium sulfate, ammonium chloride, urea, calcium cyanamide, dicyandiamide, or mix tures thereof;

(ii) phosphate fertilizers; preferably basic slag (Thomas phosphate), superphosphate, triple su perphosphate, partly digested phosphate rock, soft phosphate rock, dicalcium phosphate, thermal (fused) phosphate, aluminum calcium phosphate, or mixtures thereof;

(iii) potassium fertilizers; preferably potash ore, beneficiated potash ore, potassium chloride, po tassium chloride with magnesium, potassium sulfate, potassium sulfate with magnesium; or

(iv) lime fertilizers;

(v) magnesium fertilizers; preferably kieserite; or

(vi) mixtures thereof; preferably NP fertilizers, NK fertilizers, PK fertilizers, or NPK fertilizers.

100. Use of a solution according to any of claims 1 to 93 as fertilizer additive.

101. Use of a solution according to any of claims 1 to 93 for reducing nitrification.

102. A method for reducing nitrification comprising the step of applying a solution according to any of claims 1 to 93 to soil or a plant.

103. A method for reducing nitrification comprising the steps of

(a) adding a solution according to any of claims 1 to 93 to a fertilizer thereby obtaining a ferti lizer composition; and

(b) applying the fertilizer composition to soil or a plant.