WO2019121226A1

WO2019121226A1 - Aqueous composition comprising 2-(dimethyl-1h-pyrazole-1-yl) succinic acid and at least one further acid

Info

Publication number: WO2019121226A1
Application number: PCT/EP2018/084540
Authority: WO
Inventors: Daniel Saelinger
Original assignee: Basf Se
Priority date: 2017-12-22
Filing date: 2018-12-12
Publication date: 2019-06-27

Abstract

The present invention relates to an aqueous composition comprising 2-(dimethyl-1 H-pyrazole-1-yl) succinic acid and at least one further acid.

Description

Aqueous composition comprising 2-(dimethyl-1 H-pyrazole-1-yl) succinic acid and at least one further acid

Description

The present invention relates to an aqueous composition comprising 2-(dimethyl-1 H-pyrazole- 1-yl) succinic acid and at least one further acid.

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

Soil microorganisms convert organic nitrogen to ammonium (NH₄ ⁺) which is subsequently oxi- dized to nitrate (NO₃ ) in a process known as nitrification. Albeit very important for agriculture, nitrate is highly mobile in the soil and may be readily lost from soils by leaching to ground water. Nitrogen is further lost by microbiological denitrification to gaseous forms of nitrogen. As a result of the various losses, approximately 50% of the applied nitrogen is lost during the year following fertilizer addition (cf. Nelson and Huber; Nitrification inhibitors for corn production (2001 ), Na- tional Corn Handbook, Iowa State University).

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

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

WO 2011/032904 and WO 2013/121384 describe 2-(3,4-dimethyl-1 H-pyrazole-1-yl) succinic acid as nitrification inhibitor.

WO 2015/086823 relates inter alia to a formulation of 2-(3,4-dimethyl-1 H-pyrazole-1-yl) suc- cinic acid, which is an aqueous solution comprising from 20 to 40 % by weight of 2-(3,4-dime- thyl-1 H-pyrazole-1-yl) succinic acid, wherein said solution has a pH value of more than 7.

However, the formulations of 2-(3,4-dimethyl-1 H-pyrazole-1-yl) succinic acid described in the prior art have disadvantages. In particular, the alkaline pH value may be disadvantageous for alkaline-sensitive fertilizers, such as ammonium containing and/or urea-containing fertilizers, with which the nitrification inhibitor may be applied in combination. Due to the alkaline pH value, ammonium will be converted to ammonia resulting in a loss of nitrogen in the soil. At the same time, it is required that the formulations have a high active ingredient content to improve trans- portation logistics. Furthermore, it is desired to provide a formulation in the form of a solution without having to add organic solvents.

Therefore, it is an objective of the present invention to provide a formulation, preferably a solu- tion of 2-(3,4-dimethyl-1 H-pyrazole-1 -yl) succinic acid, which is compatible with alkaline-sensi- tive fertilizers such as ammonium-containing fertilizers.

Furthermore, it is an objective that the formulations have a high active ingredient content.

It is another objective of the present invention to provide a formulation, which also improves plant nutrition. In addition also the water input on the fertilizers, which can have a negative im- pact of the physical-chemical properties of the fertilizers, can be reduced by applying highly concentrated 2-(3,4-dimethyl-1 H-pyrazole-1 -yl) succinic acid

It has surprisingly been found that one or more of the above objectives can be achieved by the aqueous compositions as described herein.

In one embodiment, the present invention relates to an aqueous composition comprising 2-(di- methyl-1 H-pyrazole-1 -yl) succinic acid and at least one further acid.

Due to the presence of the at least one further acid, the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid is at least partly present in a form, wherein the basic nitrogen atom of the pyrazole ring is protonated or complexed. This is advantageous for the solubility properties. Therefore, solutions of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid with high concentrations can be achieved. At the same time, the acidic pH value is advantageous with a view to the combined application with al- kaline-sensitive fertilizers.

The presence of a Lewis acid based on certain metals may also improve plant nutrition, as the metal may act as macro- or micronutritient.

Preferred embodiments of the present invention can be found in the claims and the descrip- tion. It is to be understood that the features mentioned above and those still to be illustrated be- low of the subject matter of the invention are preferred not only in the respective given combina- tion, but also in other combinations without leaving the scope of the invention.

In connection with the above aspects of the present invention, the following definitions are pro- vided.

As used herein, the term“2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid” (also abbreviated as DMPSA) preferably refers to 2-(3,4-dimethyl-1 H-pyrazole-1 -yl) succinic acid, 2-(4,5-dimethyl- 1 H-pyrazole-1 -yl) succinic acid, or a combination thereof. It is to be understood that the 2-(dime- thyl-1 H-pyrazole-1 -yl) succinic acid may be present in the compositions of the invention in pro- tonated or complexed form, so that a pyrazolium cation of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid is formed. In particular, the pyrazole group of the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid will be protonated or complexed at the nitrogen atom that is not bonded to the succinic acid moiety.

As used herein, the term“2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof” therefore refers to 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the pro- tonated form thereof, the complexed form thereof or mixtures thereof. Preferably, mixtures of 2- (dimethyl-1 H-pyrazole-1 -yl) succinic acid and the protonated form thereof and/or the complexed form thereof are present. The term“complexed” is relevant, if the at least one acid is a Lewis acid. The Lewis acid may then form a Lewis acid/Lewis base-complex with the free electron pair of the nitrogen atom of the pyrazole group of the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid that is not bonded to the succinic acid moiety. The term“protonated” is relevant, if the nitrogen atom is protonated, which may not only occur in the presence of a Bronsted acid, but also in the pres- ence of a Lewis acid, if the Lewis acid reacts with water and sets free a proton.

As used herein, the term“acid” in connection with the at least one further acid that is present in the aqueous composition of the invention refers to Bronsted and/or Lewis acid. Suitable Bronsted acids include organic Bronsted acids such as fumaric acid, maleic acid, succinic acid, acetic acid, formic acid, methanesulfonic acid and combinations thereof, and/or inorganic Bronsted acids such as sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid and combi- nations thereof. Suitable Lewis acids include boric acid, non-basic salts of lithium, magnesium, calcium, aluminum, iron, copper, zinc, manganese, molybdenum, cobalt, nickel, and combina- tions thereof. The term“non-basic” preferably excludes the hydroxide salts of the listed metals. Preferred are the halides, nitrates, sulfates, phosphates, formates, and/or acetates of these metals, in particular the chlorides and nitrates. Preferred metals in the context of the above listed non-basic salts are lithium, magnesium, and calcium, in particular magnesium and cal- cium. It is to be understood that the Bronsted acids as used herein may at least partly be pre- sent in deprotonated form in the compositions of the invention, while the Lewis acids may at least partly be present in a form, wherein they have formed a complex with a hydroxyl group from the aqueous composition, so that a proton was set free, and/or the Lewis acid may at least partly be present in the form of a complex with the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid as explained above.

Different isomers of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or com- plexed form thereof are possible in the aqueous compositions of the invention. As used herein, the term“isomer” describes compounds with the same chemical formula and molecular weight, but different chemical structures. In the context of the present invention, 2-(dimethyl-1 H-pyra- zole-1 -yl) succinic acid, the protonated and/or complexed form thereof may preferably be pre- sent

in the form of 2-(3,4-dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or com- plexed form thereof;

in the form of 2-(4,5-dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or com- plexed form thereof; or

in the form of an isomer mixture comprising

(i) 2-(3,4-dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof; and

(ii) 2-(4,5-dimethyl-1 H-pyrazole-1 -yl) succinic acid , the protonated and/or complexed form thereof.

Preferably, 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is present in the isomer mixture as defined above. The possible isomers only differ in terms of the position of the methyl groups at the pyrazole group.

The term“aqueous composition” as used herein refers to a composition comprising water as solvent. Preferably, the aqueous composition according to the invention does not comprise any additional solvent in significant amounts. In particular, it is preferred that the composition corn- prises less than 30 % by weight, preferably less than 25 % by weight, more preferably less than 20 % by weight, even more preferably less than 15 % by weight, yet more preferably less than 10 % by weight, most preferably less than 5 % by weight of additional solvents. It is especially preferred that the composition comprises less than 3 % by weight, more preferably less than 1 % by weight, even more preferably less than 0.1 % by weight of organic solvents. Most prefera- bly, the composition is free of organic solvents. Further, it is preferred that of the total amount of solvents in the aqueous composition, at least 70 % weight, more preferably at least 80 % weight, even more preferably at least 90 % by weight, most preferably at least 95 % by weight, especially preferably at least 99 % by weight, particularly preferably at least 99.9 % by weight is water.

As used herein, the term“solution” in the context of the aqueous composition according to the invention refers to an aqueous composition, wherein the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is dissolved. In particular, at least 90 % by weight, preferably at least 95 % by weight, more preferably at least 99 % by weight, most pref- erably at least 99.9 % by weight of the total amount of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is dissolved. Particularly preferably, the 2- (dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is com- pletely dissolved.

Preferred embodiments regarding the aqueous composition of the invention are described hereinafter.

As indicated above, the present invention relates to an aqueous composition comprising 2-(di- methyl-1 H-pyrazole-1 -yl) succinic acid and at least one further acid.

In a preferred embodiment, the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid is at least partly present in a form, wherein the basic nitrogen atom of the pyrazole ring is protonated and/or complexed.

In another preferred embodiment, the at least one acid is at least partly present in deproto- nated form or in complexed form, i.e. in the form of a complex with the pyrazole group of 2-(di- methyl-1 H-pyrazole-1 -yl) succinic acid or in the form of a complex with a hydroxyl group from the water in the aqueous composition.

Thus, it is to be understood that the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid and the at least one further acid are present in an acid-base equilibrium or Lewis-acid/Lewis-base equilib rium in the composition of the invention.

Therefore, the present invention also relates in one embodiment to an aqueous composition comprising 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid in protonated form and the at least one further acid in deprotonated form (in case of a Bronsted acid). In another embodiment, the pre- sent invention relates to an aqueous composition comprising 2-(dimethyl-1 H-pyrazole-1 -yl) suc- cinic acid in complexed form and the at least one further acid in the form of a complex with a hy- droxyl group, so that a proton was set free in the aqueous composition, or in the form of a com- plex with the pyrazole group of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid (in case of a Lewis acid). In a preferred embodiment, said compositions additionally contain 2-(dimethyl-1 H-pyra- zole-1 -yl) succinic acid and the at least one further acid, due to acid-base or Lewis acid/Lewis base equilibrium in the aqueous composition. In addition, an excess of the at least one further acid in comparison to the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid may be present.

In view of the above, it may be preferred that the aqueous composition of the invention corn- prises 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof and a further acid, wherein the further acid may at least partly be present in the proto- nated form thereof, in case of a Bronsted acid, or the acid may at least partly be present in the complexed form thereof (including complexation with hydroxyl as well as with the pyrazole group of DMPSA), in case of a Lewis acid. These components will preferably be present in an acid-base or Lewis acid/Lewis base equilibrium.

With regard to the above described aqueous composition of the invention, it is preferred that the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is present in dissolved form.

In a preferred embodiment, the aqueous composition of the present invention is a solution. In particular, it is preferred that at least 90 % by weight, preferably at least 95 % by weight, more preferably at least 99 % by weight, most preferably at least 99.9 % by weight of the total amount of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is dissolved. Particularly preferably, the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is completely dissolved.

The solubility of the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or com- plexed form thereof may depend on the ratio of the two isomeric forms that are present in the aqueous composition.

In one embodiment, the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is present

in the form of 2-(3,4-dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or com- plexed form thereof.

In another embodiment, the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is present

in the form of 2-(4,5-dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or com- plexed form thereof.

in the form of an isomer mixture comprising

(ii) 2-(4,5-dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof.

Preferably, 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is present in the isomer mixture as defined above. In comparison to one isomer alone, the solubility of the isomer mixture may be higher.

Regarding the isomer mixture, it is preferred that

(i) 2-(3,4-dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof; and (ii) 2-(4,5-dimethyl-1 H-pyrazole-1-yl) succinic acid, the protonated and/or complexed form thereof

are present in a molar ratio of from 5:95 to 95:5, preferably from 50:50 to 95:5, more preferably from 70:30 to 90:10.

Various acids may be used as the at least one further acid in the aqueous compositions of the present invention.

In one embodiment, the at least one further acid is a Bronsted acid.

In another embodiment, the at least one further acid is a Lewis acid.

In another embodiment, the at least one further acid has pK_a value in water of 5 or lower, pref- erably in the range of from -3 to 5.

In one preferred embodiment, the at least one further acid is selected from organic Bronsted acids, which are preferably selected from the group consisting of fumaric acid, maleic acid, suc- cinic acid, acetic acid, formic acid, methanesulfonic acid, and combinations thereof.

In one particularly preferred embodiment, the at least one further acid is fumaric acid.

In another particularly preferred embodiment, the at least one further acid is maleic acid.

In another particularly preferred embodiment, the at least one further acid is succinic acid.

In another particularly preferred embodiment, the at least one further acid is acetic acid.

In another particularly preferred embodiment, the at least one further acid is formic acid.

In another particularly preferred embodiment, the at least one further acid is methanesulfonic acid.

In another preferred embodiment, the at least one further acid is selected from inorganic Bronsted acids, which are preferably selected from the group consisting of sulfuric acid, hydro- chloric acid, phosphoric acid, nitric acid, and combinations thereof.

In one particularly preferred embodiment, the at least one further acid is sulfuric acid.

In another particularly preferred embodiment, the at least one further acid is hydrochloric acid.

In another particularly preferred embodiment, the at least one further acid is phosphoric acid.

In another particularly preferred embodiment, the at least one further acid is nitric acid.

In another preferred embodiment, the at least one further acid is selected from Lewis acids, which are preferably selected from the group consisting of boric acid, non-basic salts of lithium, magnesium, calcium, aluminum, iron, copper, zinc, manganese, molybdenum, cobalt, nickel, and combinations thereof.

In one particularly preferred embodiment, the at least one further acid is boric acid.

In another particularly preferred embodiment, the at least one further acid is lithium chloride.

In another particularly preferred embodiment, the at least one further acid is lithium nitrate.

In another particularly preferred embodiment, the at least one further acid is magnesium chlo- ride.

In another particularly preferred embodiment, the at least one further acid is magnesium ni- trate.

In another particularly preferred embodiment, the at least one further acid is calcium chloride.

In another particularly preferred embodiment, the at least one further acid is calcium nitrate. The aqueous compositions of the present invention may be obtained by combining the 2-(di- methyl-1 H-pyrazole-1 -yl) succinic acid and the at least one further acid in water.

In a preferred embodiment, the composition is obtained by using the at least one acid in an amount such that the molar ratio of acid to 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid is in the range of from 1 :5 to 20: 1 , preferably from 1 :2 to 5: 1. Further details in this regard and regarding the amount of the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid in the aqueous composition are provided below.

The pH value may vary depending on the type of the at least one further acid and the amount of the at least one further acid relative to the amount of the 2-(dimethyl-1 H-pyrazole-1 -yl) suc- cinic acid in the aqueous composition of the invention.

In one preferred embodiment, the pH value of the composition is 7 or lower, preferably in the range of from 0 to 6.

In a further embodiment, the present invention relates to a process of preparing an aqueous composition for inhibiting nitrification comprising the step of

combining 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid and at least one further acid in water.

In one preferred embodiment, 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid is suspended in wa- ter, and then the at least one further acid is added.

In another preferred embodiment, 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid is added to an aqueous solution of the at least one acid.

Suitable molar ratios of further acid to 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid are in the range of from 1 :5 to 20:1 , preferably from 1 :2 to 5:1. Further details in this regard and regarding the amount of the 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid in the aqueous composition are provided below.

In a further embodiment, the present invention relates to an aqueous composition obtainable by the process as defined above.

With regard to the aqueous compositions of the invention as well as with regard to the process of the invention, the following preferences are relevant in terms of the amounts of the at least one further acid and 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated form, and/or the complexed form thereof.

In order to improve transportation logistics, it is generally preferred that the total amount of 2- (dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated form, and/or the complexed form thereof is present in the composition in an amount corresponding to at least 10 % by weight, preferably at least 20 % by weight of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid based on the total weight of the composition.

In a preferred embodiment, the total amount of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated form, and/or the complexed form thereof form thereof is present in the composition in an amount corresponding to from 10 to 60 % by weight, preferably from 20 to 50 % by weight of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid based on the total weight of the composition. In a more preferred embodiment, the total amount of 2-(dimethyl-1 H-pyrazole-1-yl) succinic acid, the protonated form, and/or the complexed form thereof is present in the composition in an amount corresponding to from 10 to 40 % by weight, preferably from 15 to 30 % by weight of 2- (dimethyl-1 H-pyrazole-1-yl) succinic acid based on the total weight of the composition.

In the following preferred embodiments, the term“2-(dimethyl-1 H-pyrazole-1-yl) succinic acid, the protonated form, and/or the complexed form thereof” is referred to as“DMPSA and/or deriv- atives thereof”, and“2-(dimethyl-1 H-pyrazole-1-yl) succinic acid” is referred to as“DMPSA”. All these preferred embodiments are optionally also preferred in combination with the above men- tioned pH value of the composition of 7 or lower, preferably from 0 to 6.

In one preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 10 to 15 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 15 to 20 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 16 to 21 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 17 to 22 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 18 to 23 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 19 to 24 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 20 to 25 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 21 to 26 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 22 to 27 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 23 to 28 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 24 to 29 % by weight of DMPSA based on the total weight of the composition. In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 25 to 30 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 26 to 31 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 27 to 32 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 28 to 33 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 29 to 34 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 30 to 35 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 31 to 36 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 32 to 37 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 33 to 38 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 34 to 39 % by weight of DMPSA based on the total weight of the composition.

In another preferred embodiment, the total amount of DMPSA and/or derivatives thereof in the composition corresponds to from 35 to 40 % by weight of DMPSA based on the total weight of the composition.

As mentioned above, these DMPSA concentrations are preferably obtained at a pH value of the composition of 7 or lower, preferably in the range of from 0 to 6, more preferably in the range of from 0 to 5.

In particularly preferred embodiments, compositions with the parameters according to table A are preferred according to the present invention.

Table A

^* Total amount of DM PSA and/or deriva- tives thereof calculated as % by weight of DMPSA based on the total weight of the composition

^** pH measured in water, i.e. the aqueous composition

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is fu- maric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is maleic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is suc- cinic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is acetic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is formic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is me- thanesulfonic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is sulfu- ric acid. In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is hydro- chloric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is phos- phoric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is nitric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is boric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is lithium chloride.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is lithium nitrate.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is mag- nesium chloride.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is mag- nesium nitrate.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is cal- cium chloride.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries A-1 to A-38 of table A, and the at least one further acid is cal- cium nitrate.

In connection with the above embodiments relating to compositions with an acidic pH value and/or certain DMPSA concentrations, it is further preferred that the composition is obtained by using the at least one further acid in an amount such that the molar ratio of further acid to 2-(di- methyl-1 H-pyrazole-1-yl) succinic acid is in the range of from 1 :5 to 20:1 , preferably from 1 :2 to 5:1.

Therefore, in particularly preferred embodiments, compositions with the parameters according to table B are preferred according to the present invention.

Table B

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is fu- maric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is maleic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is suc- cinic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is acetic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is formic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is me- thanesulfonic acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is sulfu- ric acid. In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is hydro- chloric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is phos- phoric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is nitric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is boric acid.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is lithium chloride.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is lithium nitrate.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is mag- nesium chloride.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is mag- nesium nitrate.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is cal- cium chloride.

In certain preferred embodiments, the aqueous composition of the invention is a composition according to any one of entries B-1 to B-38 of table B, and the at least one further acid is cal- cium nitrate.

The aqueous compositions as defined above are particularly advantageous for transportation of the active ingredient 2-(dimethyl-1 H-pyrazole-1-yl) succinic acid, which acts as a nitrification inhibitor. The acidic formulations may further advantageously be used in combination with alka- line-sensitive fertilizers.

In certain embodiments, the present invention therefore also relates to methods of applying the aqueous compositions as defined herein to soil or soil substitutes where plants are growing or are intended to grow.

The aqueous compositions may be applied in combination with at least one fertilizer or with a certain time lag, preferably a time lag of 1 day, 2, days, 3, days, 1 week, 2 weeks or 3 weeks.

The aqueous compositions may preferably be applied in combination with alkaline-sensitive fertilizers, such as ammonium-containing fertilizers. The compositions of the invention are suitable as nitrification inhibitors. In one embodiment, the compositions of the invention are used as nitrification inhibitors.

In one embodiment, the compositions of the invention are applied or sprayed into or onto soil, and are preferably applied together with at least one fertilizer, one nitrogen-containing fertilizer or one urea-containing fertilizer into the soil in-furrow and/or as side-dress and/or as broadcast.

In another preferred embodiment, the compositions of the invention can be used as nitrification inhibitor in combination with, and/or as additive and/or as coating material for a fertilizer, prefera- bly with/for an ammonium-containing and/or urea-containing fertilizer, more preferably with/for an ammonium-containing and/or urea-containing fertilizer selected from the group consisting of solid and liquid mineral fertilizers and organic fertilizers, most preferably with/for ammonium-containing and/or urea-containing fertilizer selected from the group consisting of ammonium nitrate, calcium ammonium nitrate, ammonium sulfate, ammonium sulfate nitrate, calcium nitrate, diammonium phosphate, monoammonium phosphate, ammonium thio sulfate, calcium cyanamide, NPK ferti- liz-ers, NK fertilizers, NP fertilizers, UAN, manure, and/or urea, particularly preferably with/for calci-um ammonium nitrate, ammonium sulfate, and/or ammonium sulfate nitrate. In another pre- ferred embodiment, the compositions of the invention can be used as nitrification inhibitor in com- bination with an ammonium-containing and/or urea-containing fertilizer selected from the group consisting of ammonium nitrate, calcium ammonium nitrate, ammonium sulfate, ammonium sul- fate nitrate, diammonium phosphate, monoammonium phosphate, ammonium thio sulfate, NK fertilizers, NP fertilizers, UAN, manure, and urea. The fertilizers can be in crystalline, granulated, compacted, prilled or ground form, and is preferably in granulated from.

In another preferred embodiment, the compositions of the invention can be applied to or on nitrogen-containing fertilizers by either mixing the compositions of the invention, in either liquid or solid form, with the fertilizers, or incorporating them into the fertilizers by granulation, compacting or prilling, by addition to a corresponding fertilizer mixture or to a mash or melt. Preferably, the compositions of the invention are applied to the surface of existing granules, compacts or prills of the nitrogen-containing fertilizer by means of spraying, powder application or impregnating, for example. This can also be done using further auxiliaries such as adhesive promoters or encasing materials. Examples of apparatuses suitable for performing such application include plates, drums, mixers or fluidized-bed apparatus, although application may also take place on conveyor belts or their discharge points or by means of pneumatic conveyors for solids. A concluding treat- ment with anticaking agents and/or anti-dust agents is likewise possible. The compositions of the invention are used in the context of fertilization with ammonium-containing and/or urea-containing fertilizer. Application takes place preferably to an agriculturally or horticulturally exploited plot.

The fertilizers can be used together, processed, combined, treated, coated, and/or molten with the compositions of the present invention.

In one embodiment, the compositions of the invention are applied to the plants preferably by spraying on the soil and/or the leaves. Here, the application can be carried out using, for exam- pie, water as carrier by customary spraying techniques using spray liquor amounts of from about 50 to 1000 l/ha (for example from 300 to 400 l/ha). The compositions of the invention may also be applied by the low-volume or the ultra-low-volume method, or in the form of microgran- ules. The compositions of the present invention can be applied pre- or post-emergence or to- gether with the seed of a crop plant. It is also possible to apply the compositions of the invention by applying seed, pretreated with a composition of the invention, of a crop plant. In a further embodiment, the compositions of the invention can be applied by treating seed. The treatment of seed comprises essentially all procedures familiar to the person skilled in the art (seed dressing, seed coating, seed dusting, seed soaking, seed film coating, seed multilayer coating, seed encrusting, seed dripping and seed pelleting) based on the compositions of the present invention as well as its compounds. Here, the compositions of the present invention can be applied diluted or undiluted.

The term“seed” comprises seed of all types, such as, for example, corns, seeds, fruits, tubers, seedlings and similar forms. Here, preferably, the term seed describes corns and seeds. The seed used can be seed of the useful plants mentioned above, but also the seed of transgenic plants or plants obtained by customary breeding methods.

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

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

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

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

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

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

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

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

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

Further envisaged coated fertilizers may be provided by reacting resin-based polymers on the surface of the fertilizer granule. A further example of providing coated fertilizers includes the use of low permeability polyethylene polymers in combination with high permeability coatings.

In specific embodiments, the composition and/or thickness of the fertilizer coating may be ad- justed to control, for example, the nutrient release rate for specific applications. The duration of nutrient release from specific fertilizers may vary, e.g. from several weeks to many months.

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

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

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

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

Any of the above mentioned fertilizers or fertilizer forms may suitably be combined. For in- stance, slow release fertilizers may be provided as coated fertilizers. They may also be com- bined with other fertilizers or fertilizer types. The same applies to the presence of the composi- tion of the present invention, which may be adapted to the form and chemical nature of the ferti- lizer and accordingly be provided such that its release accompanies the release of the fertilizer, e.g. is released at the same time or with the same frequency.

The term "fertigation" as used herein refers to the application of fertilizers, optionally soil amendments, and optionally other water-soluble products together with water through an irriga tion system to a plant or to the locus where a plant is growing or is intended to grow, or to a soil substituent as defined herein below. For example, liquid fertilizers or dissolved fertilizers may be provided via fertigation directly to a plant or a locus where a plant is growing or is intended to grow. Likewise, compositions of the present invention may be provided via fertigation to plants or to a locus where a plant is growing or is intended to grow. Fertilizers and the compositions of the present invention may be provided together, e.g. dissolved in the same charge or load of material (typically water) to be irrigated. In further embodiments, fertilizers and the compositions of the present invention may be provided at different points in time. For example, the fertilizer may be fertigated first, followed by the composition of the present invention, or preferably, the composition of the present invention may be fertigated first, followed by the fertilizer. The time intervals for these activities follow the herein above outlined time intervals for the application of fertilizers and the compositions of the present invention, for example in a time interval of from 0.25 hour to 30 days, preferably from 0.5 hour to 14 days, particularly from 1 hour to 7 days or from 1.5 hours to 5 days, even more preferred from 2 hours to 1 day. Also envisaged is a re- peated fertigation of fertilizers and compositions of the present invention, either together or in- termittently, e.g. every 2 hours, 6 hours, 12 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days or more.

In a further preferred embodiment, the fertilizer may be applied first to the soil or to the plants, followed by the composition of the present invention, or preferably, the composition of the pre- sent invention may be applied first to the soil or to the plants, followed by the fertilizer. The time intervals for these activities follow the herein above outlined time intervals for the application of fertilizers and the compositions of the present invention, for example in a time interval of from 0.25 hour to 30 days, preferably from 0.5 hour to 14 days, particularly from 1 hour to 7 days or from 1.5 hours to 5 days, even more preferred from 2 hours to 1 day. Also envisaged is a re- peated application of fertilizers and compositions of the present invention, either together or in- termittently, e.g. every 2 hours, 6 hours, 12 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days or more. In particularly preferred embodiments, the fertilizer is an ammonium-containing and/or urea containing fertilizer.

The present invention also relates to an agrochemical mixture comprising at least one fertilizer and the composition of the present invention.

The agrochemical mixture according to the present invention may comprise one fertilizer as defined herein above and a composition of the present invention. In further embodiments, the agrochemical mixture according to the present invention may comprise at least one or more than one fertilizer as defined herein above, e.g. 2, 3, 4, 5, 6, 7, 8, 9, 10 or more different fertiliz ers (including inorganic, organic and urea-containing fertilizers) and a composition of present invention.

In addition to at least one fertilizer and the composition of the present invention, an agrochemi- cal mixture may comprise further ingredients, compounds, active compounds or compositions or the like. For example, the agrochemical mixture may additionally comprise or composed with or on the basis of a carrier, e.g. an agrochemical carrier, preferably as defined herein. In further embodiments, the agrochemical mixture may further comprise at least one additional pesticidal compound. For example, the agrochemical mixture may additionally comprise at least one fur- ther compound selected from herbicides, insecticides, fungicides, growth regulators, biopesti- cides, urease inhibitors, nitrification inhibitors, and denitrification inhibitors.

In specific embodiments, the treatment may be carried out during all suitable growth stages of a plant as defined herein. For example, the treatment may be carried out during the BBCH prin ciple growth stages.

The term "BBCH principal growth stage" refers to the extended BBCH-scale which is a system for a uniform coding of phenologically similar growth stages of all mono- and dicotyledonous plant species in which the entire developmental cycle of the plants is subdivided into clearly rec- ognizable and distinguishable longer-lasting developmental phases. The BBCH-scale uses a decimal code system, which is divided into principal and secondary growth stages. The abbrevi- ation BBCH derives from the Federal Biological Research Centre for Agriculture and Forestry (Germany), the Bundessortenamt (Germany) and the chemical industry.

In one embodiment, the invention relates to a method for reducing nitrification comprising treating a plant growing on soil or soil substituents and/or the locus where the plant is growing or is intended to grow with a composition of the present invention at a growth stage (GS) be- tween GS 00 and GS > BBCH 99 of the plant (e.g. when fertilizing in fall after harvesting apples) and preferably between GS 00 and GS 65 BBCH of the plant.

In one embodiment, the invention relates to a method for reducing nitrification comprising treating a plant growing on soil or soil substituents and/or the locus where the plant is growing or is intended to grow with a composition of the present invention at a growth stage (GS) be- tween GS 00 to GS 45, preferably between GS 00 and GS 40 BBCH of the plant.

In a preferred embodiment, the invention relates to a method for reducing nitrification compris- ing treating a plant growing on soil or soil substituents and/or the locus where the plant is grow- ing or is intended to grow with a composition of the present invention at an early growth stage (GS), in particular a GS 00 to GS 05, or GS 00 to GS 10, or GS 00 to GS 15, or GS 00 to GS 20, or GS 00 to GS 25 or GS 00 to GS 33 BBCH of the plant. In particularly preferred embodi- ments, the method for reducing nitrification comprises treating a plant growing on soil or soil substituents and/or the locus where the plant is growing or is intended to grow with a composi- tion of the present invention during growth stages including GS 00.

In a further, specific embodiment of the present invention, a composition of the present inven- tion is applied to a plant growing on soil or soil substituents and/or the locus where the plant is growing or is intended to grow at a growth stage between GS 00 and GS 55 BBCH, or of the plant.

In a further embodiment of the present invention, a composition of the present invention is ap- plied to a plant growing on soil or soil substituents and/or the locus where the plant is growing or is intended to grow at the growth stage between GS 00 and GS 47 BBCH of the plant.

In one embodiment of the present invention, a composition of the present invention is applied to a plant growing on soil or soil substituents and/or the locus where the plant is growing or is in- tended to grow before and at sowing, before emergence, and until harvest (GS 00 to GS 89 BBCH), or at a growth stage (GS) between GS 00 and GS 65 BBCH of the plant.

In particularly preferred embodiments, a composition of the present invention is used for treat- ing the locus where the plant is intended to grow with a composition of the present invention be- fore planting the plant and/or before sowing the seeds of the plant.

Depending on the application method in question, the compositions according to the invention can additionally be employed in a further number of crop plants for increasing yield, for increas- ing the productivity (e.g. bio mass production, grain yield, starch content, oil content or protein content), for improving plant health or for improving or regulating plant growth. Examples of suit- able crops are the following:

Allium cepa, Ananas comosus, Arachis hypogaea, Asparagus officinalis, Avena sativa, Beta vulgaris spec altissima, Beta vulgaris spec rapa, Brassica napus var. napus, Brassica napus var. napobrassica, Brassica rapa var. silvestris, Brassica oleracea, Brassica nigra, Camellia sinensis, Carthamus tinctorius, Carya illinoinensis, Citrus limon, Citrus sinensis, Coffea arabica (Coffea canephora, Coffea liberica), Cucumis sativus, Cynodon dactylon, Daucus carota, Elaeis guineensis, Fragaria vesca, Glycine max, Gossypium hirsutum, (Gossypium arboreum, Gossy- pium herbaceum, Gossypium vitifolium), Helianthus annuus, Hevea brasiliensis, Hordeum vul- gare, Humulus lupulus, Ipomoea batatas, Juglans regia, Lens culinaris, Linum usitatissimum, Lycopersicon lycopersicum, Malus spec., Manihot esculenta, Medicago sativa, Musa spec., Ni- cotiana tabacum (N.rustica), Olea europaea, Oryza sativa, Phaseolus lunatus, Phaseolus vul- garis, Picea abies, Pinus spec., Pistacia vera, Pisum sativum, Prunus avium, Prunus persica, Pyrus communis, Prunus armeniaca, Prunus cerasus, Prunus dulcis and prunus domestica, Ribes sylvestre, Ricinus communis, Saccharum officinarum, Secale cereale, Sinapis alba, Sola- num tuberosum, Sorghum bicolor (s. vulgare), Theobroma cacao, Trifolium pratense, Triticum aestivum, Triticale, Triticum durum, Vicia faba, Vitis vinifera, Zea mays.

Preferred crops are Arachis hypogaea, Beta vulgaris spec altissima, Brassica napus var. na- pus, Brassica oleracea, Citrus limon, Citrus sinensis, Coffea arabica (Coffea canephora, Coffea liberica), Cynodon dactylon, Glycine max, Gossypium hirsutum, (Gossypium arboreum, Gossy- pium herbaceum, Gossypium vitifolium), Helianthus annuus, Hordeum vulgare, Juglans regia, Lens culinaris, Linum usitatissimum, Lycopersicon lycopersicum, Malus spec., Medicago sativa, Nicotiana tabacum (N.rustica), Olea europaea, Oryza sativa , Phaseolus lunatus, Phaseolus vulgaris, Pistacia vera, Pisum sativum, Prunus dulcis, Saccharum officinarum, Secale cereale, Solanum tuberosum, Sorghum bicolor (s. vulgare), Triticale, Triticum aestivum, Triticum durum, Vicia faba, Vitis vinifera and Zea mays.

Especially preferred crops are crops of cereals, corn, soybeans, rice, oilseed rape, cotton, potatoes, peanuts or permanent crops.

The mixtures or compositions according to the invention can also be used in crops which have been modified by mutagenesis or genetic engineering in order to provide a new trait to a plant or to modify an already present trait.

The term "crops" as used herein includes also (crop) plants which have been modified by muta- genesis or genetic engineering in order to provide a new trait to a plant or to modify an already present trait.

Mutagenesis includes techniques of random mutagenesis using X-rays or mutagenic chemi- cals, but also techniques of targeted mutagenesis, in order to create mutations at a specific lo- cus of a plant genome. Targeted mutagenesis techniques frequently use oligonucleotides or proteins like CRISPR/Cas, zinc-finger nucleases, TALENs or meganucleases to achieve the tar- geting effect.

Genetic engineering usually uses recombinant DNA techniques to create modifications in a plant genome which under natural circumstances cannot readily be obtained by cross breeding, mutagenesis or natural recombination. Typically, one or more genes are integrated into the ge- nome of a plant in order to add a trait or improve a trait. These integrated genes are also re- ferred to as transgenes in the art, while plant comprising such transgenes are referred to as transgenic plants. The process of plant transformation usually produces several transformation events, wich differ in the genomic locus in which a transgene has been integrated. Plants corn- prising a specific transgene on a specific genomic locus are usually described as comprising a specific“event”, which is referred to by a specific event name. Traits which have been intro- duced in plants or hae been modified include in particular herbicide tolerance, insect resistance, increased yield and tolerance to abiotic conditions, like drought.

Increased yield has been created by increasing ear biomass using the transgene athb17, be- ing present in corn event MON87403, or by enhancing photosynthesis using the transgene bbx32, being present in the soybean event MON87712.

Crops comprising a modified oil content have been created by using the transgenes: gm-fad2- 1 , Pj.D6D, Nc.Fad3, fad2-1 A and fatb1-A. Soybean events comprising at least one of these genes are: 260-05, MON87705 and MON87769.

Tolerance to abiotic conditions, in particular to tolerance to drought, has been created by using the transgene cspB, comprised by the corn event MON87460 and by using the transgene Hahb- 4, comprised by soybean event IND-00410-5.

Traits are frequently combined by combining genes in a transformation event or by combining different events during the breeding process. Preferred combination of traits are herbicide toler- ance to different groups of herbicides, insect tolerance to different kind of insects, in particular tolerance to lepidopteran and coleopteran insects, herbicide tolerance with one or several types of insect resistance, herbicide tolerance with increased yield as well as a combination of herbi- cide tolerance and tolerance to abiotic conditions.

Plants comprising singular or stacked traits as well as the genes and events providing these traits are well known in the art. For example, detailed information as to the mutagenized or inte- grated genes and the respective events are available from websites of the organizations“Inter- national Service for the Acquisition of Agri-biotech Applications (ISAAA)”

(http://www.isaaa.org/gmapprovaldatabase) and the“Center for Environmental Risk Assess- ment (CERA)” (http://cera-gmc.org/GMCropDatabase), as well as in patent applications, like EP3028573 and WO2017/01 1288.

The use of compositions according to the invention on crops may result in effects which are specific to a crop comprising a certain gene or event. These effects might involve changes in growth behavior or changed resistance to biotic or abiotic stress factors. Such effects may in particular comprise enhanced yield, enhanced resistance or tolerance to insects, nematodes, fungal, bacterial, mycoplasma, viral or viroid pathogens as well as early vigour, early or delayed ripening, cold or heat tolerance as well as changed amino acid or fatty acid spectrum or content.

In an equally preferred embodiment, the present invention relates to a method for improving the nitrification-inhibiting effect, wherein the seeds, the plants or the soil are treated with a Nl effective amount of the composition of the invention.

The term "Nl effective amount" denotes an amount of the composition of the invention, which is sufficient for achieving nitrification-inhibiting effects as defined herein below. More exemplary information about amounts, ways of application and suitable ratios to be used is given below. Anyway, the skilled artisan is well aware of the fact that such an amount can vary in a broad range and is dependent on various factors, e.g. weather, target species, locus, mode of applica- tion, soil type, the treated cultivated plant or material and the climatic conditions.

According to the present invention, the nitrification-inhibiting effect is increased by at least 2%, more preferably by at least 4%, most preferably at least 7 %, particularly preferably at least 10 %, more particularly preferably by at least 15%, most particularly preferably by at least 20%, particularly more preferably by at least 25%, particularly most preferably by at least 30%, partic- ularly by at least 35%, especially more preferably by at least 40%, especially most preferably by at least 45%, especially by at least 50%, in particular preferably by at least 55%, in particular more preferably by at least 60%, in particular most preferably by at least 65%, in particular by at least 70%, for example by at least 75%. In general, the increase of the nitrification-inhibiting ef- fect may be for example 5 to 10 %, more preferably 10 to 20 %, most preferably 20 to 30%. The nitrification-inhibiting effect can be measured according to the Example 2 as shown below.

The present invention is further illustrated by the following examples.

Examples:

Example 1

Aqueous compositions according to the invention were prepared according to the following procedure.

An aqueous solution of the acid (1 -18.8 eq.) was stirred at room temperature. Solid DMPSA (1 -3 g, 98.9% purity, 3,4-isomer : 4,5-isomer = 77 : 23) was added portionwise to reach the indi- cated amount and pH was measured after a solution was formed.

It was tested whether a solution could be obtained. The results are provided in the following table 1 .

Table 1

^* Total amount of DMPSA and/or derivatives thereof calculated as % by weight of DMPSA based on the total weight of the composition

Example 2:

The DMPSA active ingredient analysis (hereinafter referred to as“a.i. analysis DIN EN 17090”) has been done according to the method DIN EN 17090 (“Fertilizers - Determination of nitrifica- tion inhibitor DMPSA in fertilizers - Method using high-performance liquid chromatography (HPLC); German and English version prEN 17090:2017”).

The nitrification inhibition effect of the aqueous compositions according to the invention has been determined as follows:

100 g soil is filled into 500 ml plastic bottles (e.g. soil sampled from the field) and is moistened to approx. 50% water holding capacity. 10 mg nitrogen in the form of ammoniumsulfate-N is added to the soil. Prior to soil mixing, the a.i. is added to reach a final concentration of 0.1 or 1 % a.i. of applied ammonium-N. Bottles are capped but loosely to allow air exchange. The bottles are then incubated at 20°C for up to 14 days.

For analysis, 300 ml of a 1 % hGSC -solution is added to the bottle containing the soil and shaken for 2 hrs in a horizontal shaker at 150 rpm. Then the whole solution is filtered through a Macherey- Nagel Filter MN 807 ¼. Ammonium and nitrate content is then analyzed in the filtrate in an auto- analyzer at 550 nm (Merck, AA1 1 ).

The a.i. analysis DIN EN 17090 was conducted for several samples according to the method as described above, and the results are provided in the following table 2 (a.i. analysis). The nitrifica- tion inhibition effect was measured according to the method as described above, and the results are provided in the following table 3 (nitrification inhibition effect). Active ingredient is referred to as“a.i.”. 3,4-dimethylpyrazole phosphate is referred to as“DMPP”. Calculations are done according to the Bohland equation:

(N03-N without NI at end of incubation N03-N with NI at end of incubation) inhibition in % = - x 100

(N03-N without NI at end of incubation - N03-N at beginning)

(Bohland equation)

The Bohland equation is described in Bohland, H., et al. (1973)„Mittel zur Hemmung bzw. Re- gelung der Nitrifikation von Ammoniumstickstoff in Kulturboden". DDR-Wirtschaftspatent (Eco- nomic patent of the German Democratic Republic) C 05c 169 727. Cited by: Peschke, H. (1985)„Zur Bewertung der inhibierenden Wirkung von Nitrifiziden im Boden", Zbl. Mikrobiol. 140, pp. 583-588.

Table 2

Table 3

^*= No. refers to the number of aqueous composition as specified in Table 1 (with further a.i. analysis in Table 2).

^**= according to the Bohland equation (see above).

The results in Table 3 show that the aqueous compositions according to the invention also have a good nitrification inhibition effect.

Claims

1. An aqueous composition comprising 2-(dimethyl-1 H-pyrazole-1-yl) succinic acid and at least one further acid.

2. The aqueous composition according to claim 1 , wherein the 2-(dimethyl-1 H-pyrazole-1-yl) succinic acid is at least partly present in a form, wherein the basic nitrogen atom of the pyrazole ring is protonated and/or complexed.

3. The aqueous composition according to claim 1 or 2, wherein the at least one acid is at least partly present in deprotonated and/or complexed form.

4. The aqueous composition according to any one of claims 1 to 3, wherein the aqueous composition is a solution.

5. The aqueous composition according to any one of claim 1 to 4, wherein the 2-(dimethyl- 1 H-pyrazole-1-yl) succinic acid, the protonated and/or complexed form thereof is present

in the form of 2-(3,4-dimethyl-1 H-pyrazole-1-yl) succinic acid, the protonated and/or com- plexed form thereof;

in the form of 2-(4,5-dimethyl-1 H-pyrazole-1-yl) succinic acid, the protonated and/or com- plexed form thereof; or

in the form of an isomer mixture comprising

(i) 2-(3,4-dimethyl-1 H-pyrazole-1-yl) succinic acid, the protonated and/or complexed form thereof; and

(ii) 2-(4,5-dimethyl-1 H-pyrazole-1-yl) succinic acid, the protonated and/or complexed form thereof.

6. The aqueous composition according to any one of claims 1 to 5, wherein the composition is obtained by using the at least one acid in an amount such that the molar ratio of acid to 2-(di- methyl-1 H-pyrazole-1-yl) succinic acid is in the range of from 1 :5 to 20:1 , preferably from 1 :2 to 5:1.

7. The aqueous composition according to any one of claims 1 to 6, wherein the at least one further acid is selected from acids having a pK_a value in water of 5 or lower, preferably in the range of from -3 to 5.

8. The aqueous composition according to any one of claims 1 to 7, wherein the at least one further acid is selected from organic Bronsted acids, which are preferably selected from the group consisting of fumaric acid, maleic acid, succinic acid, acetic acid, formic acid, me- thanesulfonic acid and combinations thereof.

9. The aqueous composition according to any one of claims 1 to 7, wherein the at least one further acid is selected from inorganic Bronsted acids, which are preferably selected from the group consisting of sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, and combina- tions thereof.

10. The aqueous composition according to any one of claims 1 to 7, wherein the at least one further acid is selected from Lewis acids, which are preferably selected from the group consist- ing of boric acid, non-basic salts of lithium, magnesium, calcium, aluminum, iron, copper, zinc, manganese, molybdenum, cobalt, nickel, and combinations thereof.

1 1 . The composition according to any one of claims 1 to 10, wherein the total amount of 2-(di- methyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is present in the composition in an amount corresponding to at least 10 % by weight, preferably at least 20 % by weight of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid based on the total weight of the corn- position.

12. The aqueous composition according to any one of claims 1 to 1 1 , wherein the total amount of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is present in the composition in an amount corresponding to from 10 to 60 % by weight, preferably from 20 to 50 % by weight of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid based on the total weight of the composition.

13. The aqueous composition according to any one of claims 1 to 1 1 , wherein the total amount of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid, the protonated and/or complexed form thereof is present in the composition in an amount corresponding to from 10 to 40 % by weight, preferably from 15 to 30 % by weight of 2-(dimethyl-1 H-pyrazole-1 -yl) succinic acid based on the total weight of the composition.

14. The aqueous composition according to any one of claims 1 to 13, wherein the pH value of the composition is 7 or lower, preferably in the range of from 0 to 6.

15. Use of the aqueous composition according to anyone of the claims 1 to 14 as nitrification in- hibitor in combination with an ammonium-containing and/or urea-containing fertilizer.

16. Use according to claim 15, wherein the ammonium-containing and/or urea-containing ferti- lizer is selected from the group consisting of ammonium nitrate, calcium ammonium nitrate, am- monium sulfate, ammonium sulfate nitrate, di-ammonium phosphate, monoammonium phos- phate, ammonium thio sulfate, NK fertilizers, NP fertilizers, UAN, manure, and urea.

17. Use according to claim 15, wherein the ammonium-containing and/or urea-containing ferti- lizer is selected from the group consisting of calcium ammonium nitrate, ammonium sulfate, and/or ammonium sulfate nitrate.