AU600120B2

AU600120B2 - Nitrification-inhibiting agent

Info

Publication number: AU600120B2
Application number: AU14638/88A
Authority: AU
Inventors: Werner Dr. Goll; Svatopluk Dr. Solansky; Richard Dr. Youngman
Original assignee: SKW Trostberg AG
Current assignee: Evonik Operations GmbH
Priority date: 1987-05-02
Filing date: 1988-04-14
Publication date: 1990-08-02
Anticipated expiration: 2008-04-14
Also published as: EP0289757B1; IL86205A0; DK167061B1; IN168234B; CN1031071A; EP0289757A3; SU1650005A3; EP0289757A2; ATE52995T1; DE3714729A1; KR880013856A; AU1463888A; HUT46635A; CS270586B2; FI882031A0; ES2015976B3; ZA882899B; FI882031A; DD281592A5; DK205288A

Abstract

1. Nitrification-inhibiting agent, characterised in that it consists of a) dicyandiamide and b) guanylthiourea and/or ammonium thiosulphate, as well as possibly c) ammonium phosphate.

Description

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CO;MOi\WEALTH OF AUSTRALIA I 1 Patent Act 1952 0 COMPLETE S P E C I F I C A T I N

(ORIGINAL)

Class Int. Class Application Number Lodged Complete Specification Lodged Accepted Published S Priority Related Art m IYe(NV -al- st CIII1/IT d

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I L"L~LL~L~Y"Y "-*U~~-UUlillYI)IIlL~SnCY~Y 2 May 1987 Name of Applicant Address of Applicant Actual Inventor/s SKW TROSTBERG AKTIENGESELLSCHAFT Dr.-Albert-Frank-Strasse 32 D-8223 Trostberg Federal Republic of Germany Dr. Svatopluk Solansky; Dr. Werner Goll; Dr. Richard Youngman F.B. RICE CO., Patent Attorneys, 28A Montague Street, BALMAIN 2041.

c Address for Service .1 Complete Specification for the invention entitled: NITRIFICATION-INHIBITING AGENT The following statement is a full description of this invention including the best method of performing it known to us/me:i i; RI~ il~IIIW1I---- 11111-1 1~ 1~3~ 2 The present invention relates to an agent for inhibiting nitrification of ammonium-nitrogen, in particular in mineral and organic fertilizers in the soil.

It is known that ammonium nitrogen in the soil is converted relatively quickly into nitrate nitrogen by bacteria. This nitrification process is considerably 9999 influenced by the temperature, soil moisture content, ooo pH and biological activity in the soil.

9 Since nitrate nitrogen, in contrast to ammonium nitrogen, does not adhere to soil particles, it can very easily be leached during precipitation, in particular on light, permeable soils. In this fashion, the nitrogen is lost to the plants as an important nutrient. In addition, nitrate accumulation in ground water or drinking water can occur, which, under certain circumstances, can lead to health problems.

Besides leaching losses, also considerable losses of gaseous nitrogen occur through denitrification of I M nitrate nitrogen.

These losses of nitrogen can be reduced, and the utilization of nitrogen-containing fertilizers can be decisively improved, by adding nitrification-inhibiting agents.

Thus, a number of nitrification-inhibiting agents, for example based on pyridine, aniline, chlorine or sulphur derivatives have been developed for this purpose.

q -1, 3 However, these compounds have various disadvantages in practice, such as, for example, high volatility, which makes expensive incorporation into the soil necessary. In addition, these compounds are generally toxic and/or leave toxic residues in the soil. From I Q* the ecological point of view, only those known nitrifica. oo ation-inhibiting substances which are neither toxic nor throw up residue problems can thus be recommended for 0o practical use. These include, in particular, nitrogen- I containing compounds such as, for example, dicyandiamide, guanylthioruea or ammonium thiosulphate, which are degraded completely in the soil to form nitrogen 0 which is available to plants. The low activity and t< duration of action of these compounds compared, for example, to pyridine derivatives is disadvantageous.

They must therefore be used in relatively large amounts, causing not only financial problems, but also a number of applicational problems.

The present invention had the object of developi0 ing a nitrification-inhibiting agent which does not j have the disadvantages mentioned of the prior art, but has an excellent activity and good application S; possibilities and is without toxicological and residue problems.

This object was achieved according to the invention by a nitrification-inhibiting agent which comprises 4 4 a) dicyandiamide and b) guanylthiourea and/or ammonium thiosulphate and/or ammonium phosphate.

This is because it has surprisingly been shown that the agent according to the invention effects a o significantly more intensive and longer-lasting inhibit- 0 a 0 o ion of nitrification than results from addition of the o o inhibitory effects of the individual components a) and 0o This synergistic effect, which is also strongly 6 4 developed in combination with several individual components, was in no way foreseeable.

The nitrification-inhibiting agent corresponding to the present invention comprises component namely dicyandiamide, and at least one further component b), selected from the group comprising guanylthiourea, ammonium thiosulphate and ammonium phosphate, so that it comprises two to four individual components.

The ratio of the individual components to one another can be varied with broad limits, the magnitude of the synergistic effect naturally varying.

In two-component systems, mixtures comprising A :to 80% by weight of dicyandiamide and 20 to 80% by weight of guanylthiourea are to be regarded as preferred.

Three-component systems which have proved particularly successful are mixtures comprising 20 to 70% by weight of dicyandiamide, to 70% by weight of ammonium thiosulphate and 5 to 60% by weight of ammonium phosphate.

Finally, the agent according to the invention can be employed as a four-component system, preferably comprising to 60% by weight of dicyandiamide o 00 20 to 60% by weight of guanylthiourea "o 10 to 50% by weight of ammonium thiosulphate and a o 10 to 50% by weight of ammonium phosphate.

0oo0 In the context of the present invention, ammonium S phosphate is taken to mean ammonium-containing phosphate I compounds, in particular ammonium dihydrogen phosphate, 9 diammonium hydrogen phosphate and ammonium polyphosphate.

The nitrification-inhibiting agent according to the invention can be applied alone and in combination with nitrogen-containing fertilizers.

to If it is applied without fertilizers, an applic- 'o ation rate of 0.1 to 300 kg/ha, preferably 1 to kg/ha, is recommended, it being possible for application to take place before, at the same time as or after fertilization.

If, in contrast, the agent according to the Si', invention is used in combination with the nitrogen- Scontaining fertilizer, the nitrification of which fertilizer is to be inhibited by said agent, it is suitably used in an amount of 0.1 to 30% by weight, preferably 1 to 15% by weight, relative to the fertilizer.

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6 .Suitable nitrogen-containing fertilizers are both mineral and/or organic fertilizers, where all ammonium salts, such as, for example, ammonium nitrate or ammonium sulphate, and also ammonia or urea can be employed in single- and multi-nutrient fertilizers in o o o o0 the case of the mineral nitrogen-containing 0 00 o 0 0 Sfertilizers. Organic fertilizers are taken to mean, 0 0 .0 for example, liquid manure, sewage, sewage sludge and e000 the like.

QQ4o9 04 The use of the agent according to the invention 0 is without problems as a consequence of its good 0 00 applicational possibilities. It is equally highly 0 o0 suitable for solid and liquid fertilizers.

0"9* In order to prepare solid fertilizers, a controlled amount of the nitrification-inhibiting agent according to the invention is added to the fertilizers using conventional devices and mixed with these fertilizers or granulated, prilled or compacted together with them.

In general, no problems occur either during addition S and mixing of the agent according to the invention with liquid fertilizers (in the form of solutions or suspensions). The addition and mixing can be carried out during the preparation of the fertilizer solution or suspension or subsequently. In addition, the agent according to the invention is excellently suitable for the preparation of an aqueous suspension which can be applied using conventional plant sprayers. In addition, c 1 L 7 application can be combined with application of plantprotection agents and pesticides.

The nitrification-inhibiting agent correspondinc to the present invention enables the amount of active compound to be reduced markedly compared to the individual S'o, components for the same activity and duration of action.

Since all components have low toxicity and leave no 00 dangerous residues in the soil, the agent proposed is #000 *to excellently suitable for practical use.

010 The following examples are intended to illustrate the invention in greater detail, but without limiting o it.

0 Example 1 In an incubation experiment, 100 g of soil (sandy loam, pH 7.2) were mixed with 20 mg of urea nitrogen and the following amounts of inhibitors: Experiment 1 1.5 mg of dicyandiamide (DCD) Experiment 2 1.5 mg of guanylthiourea (GTU) Experiment 3 1.5 mg of DCD 1.5 mg of GTU As control, the same urea dose, but without inhibitors, was used in the soil. The soil was E incubated at 60% relative air humidity and 20 0 C in litre plastic bottles. After an incubation time of 8, 12 and 16 weeks, the content of nitrate nitrogen in the soil was determined and the nitrification inhibition calculated from this in according to the following formula: 8 Nitrification inhibition a b x 100 a c a nitrate nitrogen b nitrate nitrogen c nitrate nitrogen Results: content content content the control the experiment the soil I Tr I I t I I I; r 111l inhibition in 8 weeks 12 weeks 16 weeks Experiment 1: mg of DCD Experiment 2: mg of GTU Addition exper. 1 exper, 2 Experiment 3: mg of DCD 1.5 mg of GTU

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i I I '4 4 Common application of dicyandiamide and guanylthiourea produced nitrification inhibition which was 7, 22 and 34 percentage points higher than addition of the inhibition of the individual components.

Example 2 The experiment was carried out as described in Example 1, but using ammonium sulphate as the nitrogen source.

17 9 Results: inhibition in 8 weeks 12 weeks 16 weeks Experiment 1: mg of DCD 23 10 0 Experiment 2: 1.5 mg of GTU 50 38 13 Addition exper. 1 exper. 2 73 48 13 Experiment 3: 1.5 mg of DCD 1.5 mg of GTU 82 66 44 Common application of dicyandiamide and guanyl- B* I I to 4 thiourea produced nitrification inhibition which was 9, 18 and 31 percentage points higher than addition of an tLI inhibition of the individual components.

Example 3 Several experiments were carried out as described in Example 2, but using various inhibitor combinations of dicyandiamide and guanylthiourea. After an incubation time of 12 weeks, the active ingredient combinations surpassed the additive inhibition of the individual components by the following percentage i points: 0.5 mg of DCD 2.5 mg of GTU 17% mg of DCD 2.0 mg of GTU 21% mg of DCD 1.5 mg of GTU 22% mg of DCD 1.0 mg of GTU mg of DCD 0.5 mg of GTU 10 Example 4 The experiment was carried out as described in Example 1, but using ammonium thiosulphate (ATS) as a second component of the inhibitor combination. The incubation time was 4, 6 and 8 weeks.

0, Results: inhibition in 4 weeks 6 weeks 8 weeks o Experiment 1: mg of DCD 50 36 21 Experiment 2: mg of ATS 12 6 2 Addition experiment 1 experiment 2 62 42 23 Experiment 3: mg of DCD mg of ATS 65 50 38 Common application of dicyandiamide and ammonium thiosulphate produced nitrification inhibition which was 3, 8 and 15 percentage points higher than addition *i of the inhibition of the individual components.

j0 Example i The experiment was carried out as described in S Example 1, but using a triple combination, comprising dicyandiamide (DCD), guanylthiourea (GTU) and ammonium thiosulphate (ATS). The incubation time was 8, 12 and 16 weeks.

V -t 11 Results: inhibition in 8 weeks 12 weeks 16 weeks Experiment 1: mg of DCD 15 2 0 Experiment 2: mg of GTU 41 23 8 r Experiment 3: mg of ATS 2 0 0 1 Addition experiment 1 experiment 2 experiment 3 58 25 8 Experiment 4: mg of DCD 1.0 mg of GTU 1.0 mg of ATS 77 60 48 The triple combination of dicyandiamide, guanylthiourea and ammonium thiosulphate produced nitrification inhibition which was 19, 35 and 40 percentage '1 points higher than addition of the inhibition of the i individual components.

Example 6 The experiment was carried out as described in i Example 1, ammonium polyphosphate (APP) in the form of a commercially available NP solution (10 34) being added to the various inhibitor combinations. The incubation time was 4 weeks in the experiments 1 and 2 and 12 weeks in the experiments 3 and 4.

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12 o o 0 0 0 0 0 o I t l I II Results: Experiment 1: mg of DCD mg of ATS Experiment 2: mg of DCD 1.5 mg of ATS Experiment 3: mg of DCD 1.0 mg of GTU 1.0 mg of ATS Experiment 4: 1.0 mg of DCD mg of GTU mg of ATS without APP 66% inhibition with APP 75% inhibition without APP 60% inhibition with APP 73% inhibition Addition of ammonium polyphosphate increases the inhibition of nitrification by 9 or 13 percentage points respectively.

Example 7 In a pot experiment (7 kg of soil in a Mitscherlich pot), the influence of inhibitor combinations comprising dicyandiamide (DCD) and guanylthiourea (GTU) on the leaching of nitrate nitrogen after fertilization with urea was investigated. The following proportions of the applied urea nitrogen were leached within the first three weeks after fertilization: Urea without inhibitor 48.2% Urea with 10% of DCD nitrogen 19.9% Urea with 10% of GTU nitrogen 14.2% Urea with 5% of DCD nitrogen 5% of GTU nitrogen 10.3% .s ij a U u i Ir a I a rr Iplsmnn~ 13 I It t It QI I S It I *t St Iflt( It Is 1i

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t0~ I.,o Example 8 In a field experiment, the effect of the inhibitor combination comprising dicyandiamide (DCD), guanylthioruea (GTU) and ammonium thiosulphate (ATS) on the yield of sugar beet was tested. The active ingredient combination was applied before sowing the sugar beet together with urea ammonium nitrate solution (UAN) at a rate of 200 kg/ha of nitrogen (incl. inhibitor nitrogen). The following yields were achieved: Fertilization Yield UAN without inhibitor UAN with 10% of DCD nitrogen UAN with 6% of DCD nitrogen 4% of ATS nitrogen UAN with 4% of DCD 2% of GTU nitrogen 4% of ATS nitrogen t/ha S 71.4 S 73.0 75.1 S 76.6 100.0 102.3 105.2 107.3 'i 1 I 2

Claims

1. Nitrification-inhibiting agent characterized in that it comprises a) dicyandiamide and b) at least one of guanylthiourea and ammonium thiosulphate and, optionally, c) ammonium phosphate.

2. Agent according to Claim 1, characterized in that it comprises 20 to 80% by weight of dicyandiamide and 20 to 80% by weight of guanylthiourea.

3. Agent according to Claim 1, characterized in that it comprises 20 to 70% by weight of dicyandiamide to 70% by weight of ammonium thiosulphate and 10 to 60% by weight of ammonium phosphate.

4. Agent according to Claim 1, characterized in that it comprises 20 to 60% by weight of dicyandiamide to 60% by weight of guanylthiourea to 50% by weight of ammonium thiosulphate and to 50% by weight of ammonium phosphate

5. Agent according to any one Claims 1 to 4, characterized in that it contains as ammonium phosphate ammonium polyphosphate.

6. Agent according to any one of claims 1 to characterized in that it is present in combination with a nitrogen-containing fertilizer. WT a 15

7. Process for inhibiting nitrification using an agent according to any one of Claims 1 to 6, character- ized in that the agent is applied at a rate of 0.1 to 300 kg/ha, preferably 1 to 60 kg/ha.

8. Process according to Claim 7, characterized in that the agent is used in combination with a nitrogen- containing fertilizer in an amount of 0.1 to 30% by weight, preferably 1 to 15% by weight, relative to the fertilizer. oa, a0 0 0000 0000 a Dated this 13th day of April 1988 E SKW TROSTBERG AKTIENGESELLSCHAFT Patent Attorneys for the Applicant F.B. RICE CO. ii A I; i