BACKGROUND Nitrification is the process of conversion of a relatively immobile form of nitrogen (N) from an ammonium (NH4+) form into the more mobile nitrate (N03-) form. During nitrification the NH4+ is believed to be first oxidised to nitrite (NO2-) and that this conversion is largely brought about by Nitrosomonas bacteria.

Thereafter the N02-in turn, it is believed, is oxidised to NOs'by Nitrobacter bacteria.

Nitrates, produced from the nitrification process, is subject to losses by leaching from soils and can potentially contaminate surface and ground water.

Nitrates can also undergo denitrification in the absence of oxygen by a taxonomically diverse group of microorganisms to gaseous oxides of N (e. g. N20) and nitrogen gas (N2), which are commonly lost to the atmosphere. These losses of N account for inefficiencies in the use of applied N by plants, whether from N including fertilisers or urine, or both. N20 is one of the greenhouse gases and also has a catalytic effect on the destruction of stratospheric ozone.

An approach previously proposed to increase plant N use efficiency and minimise potential adverse environmental effects by nitrogeneous compounds is the use of nitrification inhibitors. Since NH4+ is less subject to loss from soils, delaying the microbial transformation (nitrification process) of NH4+ to N03-through the use of nitrification inhibitors can result in an increase in potential N availability for plant growth and a decrease in N03-and N20 production.

Nitrification inhibitors are compounds that delay the microbial oxidation of NH4+ to NO2- (the first step of the nitrification process) for a certain period by depressing the activity of Nitrosomonas bacteria in soils. The second step of nitrification it is believed normally is not influenced.

An ideal nitrification inhibitor should have the following characteristics: - Specificity. It should block the conversion of NH4+ to N03-and be non-toxic to other soil organisms, animals and humans.

- Mobility. It should move with N fertilisers or nutrient solution.

- Persistence. It should stay in soils for an adequate period.

- Economy. It should be cheap as it is frequently to be used as an additive to fertilisers.

Examples of compositions that hitherto have been considered for application to soils or pasture include those disclosed by Sumitomo Chemical Co Ltd in its New Zealand Patent Specification No. 161791 where they disclose a nitrophosphate fertiliser containing a nitrification inhibitor in the amount of from 1 to 20% by weight based on total nitrogen content and where the fertiliser contains nitrate nitrogen of from 20 to 80% by weight based on total nitrogen content.

Examples of nitrification inhibitors given in New Zealand are as follows: - N-2, 5-dichlorophenyl succinamic acid - 2-chloro-6-trichloromethyl pyridine ("Nitrapyrin") - dicyandiamide ("DCD or"DCDIN"") which is HN=C (NH2) -NH-CN - zinc ethylene-bis-dithiocarbamate - 2, 4,6-trichloroaniline <BR> <BR> <BR> <BR> - pentachlorophenol<BR> <BR> <BR> <BR> - thio-urea.

Other known nitrification inhibitors include ATS (ammonium thiosulphate) and water soluble DMPP (3,4-dimethypyrazole phosphate). Still other options are discussed in the prior art.

The term"nitrification inhibitor"or its plural refers to any suitable compound or compounds and is inclusive of those discussed above.

It is an object of the present invention to provide advantageous compositions inclusive of nitrification inhibitor (s) capable of agricultural use.

BRIEF DESCRIPTION OF THE INVENTION In one aspect the invention is a method of producing a composition suitable (alone or in conjunction with at least one other material) to be applied to the soil and/or pasture, said method comprising or including formulating a slurry of at least one zeolite as a particulate carrier with a liquid (preferably at least water) after, as and/or prior to the inclusion of at least one nitrification inhibitor therein, and drying the slurry to result in an at least substantially dry particulate material with the zeolite carrying the nitrification inhibitor (s).

The nitrification inhibitor (s) may be soluble to some extent in the liquid but preferably is present as a particle prior to the drying step.

Preferred particle size ranges for the solid carrier or zeolite is from 1 to 3mm (typically 100% passing a 3mm screen and < 1% a lmm screen).

Chemically preferably the zeolite is 65 to 95% w/w mordenite and 5 to 20% smectite.

The nitrification inhibitor is preferably (but optionally) able to pass through a 200m screen.

The nitrification inhibitor (s) prior to drying is supported in the liquid by a suspension agent (preferably a gum).

Preferably the slurry prior to drying (preferably to a dryness of less than 8 % w/w water/composition) includes as the suspension agent or otherwise a tackifier (e. g. a gum).

Examples of suitable gums for one or both purposes include microbial polysaccharides such as dextran, gellan, rhamsan, guar and xanthan gums; polysaccharide derivatives such as hydroxymethylcellulose, hydroxyethylcellulose, microcrystalline cellulose and modified starches; and synthetic polymers such as polyvinyl alcohols, polyvinyl acetates and cross-linked polyacrylates.

In another aspect the invention is a method of producing a composition suitable (alone or in conjunction with at least one other material) to be applied to the soil and/or pasture, said method comprising or including the steps of formulating an aqueous slurry of a particulate nitrification agent or agents together with one or both of a suitable suspension stabilising agent and a zeolite carrier or carriers in a particulate form, and drying the slurry to at least a substantially dried particulate form which has the nitrification inhibitor (s) adhered to or otherwise carried by the zeolite (s) carrier.

Preferably the formation of said slurry is a stage wise process.

Preferably said stage wise process involves optionally milling in water the nitrification inhibitor (s).

Preferably the suspension stabilising agent and/or tack providing agent is added to the initial slurry and thereafter the zeolite (s) carrier is added. In preferred forms of the present invention the nitrification agent is selected from the range of particulate nitrification agents including DCD and ATS.

Preferably said suspension stabilising agent and/or tack providing agent is a gum. Preferably said gum is a polysaccharide gum such as, by way of example, one or more of xanthan gum, guar gum, etc. [e. g. as earlier exemplified].

Preferably the composition produced by the process is any of the compositions hereinafter described.

In yet a further aspect the present invention consists in the aforementioned process (es) and the optional additional step of adding a flow enhancing agent such as a particulate agent such as talc to the dried product.

In still a further aspect the present invention consists in the aforementioned process (es) and the additional optional step (irrespective of whether or not a flow enhancing agent has been utilised) of admixing or otherwise associating the zeolite carried nitrification inhibitor (s) with a fertilising agent, compound or composition irrespective of whether or not it includes nitrogen. Preferably however it includes nitrogen and may be, by way of example, urea.

In another aspect the present invention consists in a composition for pasture application in the form of particulate zeolite or zeolites carrying at least one nitrification inhibitor.

Preferably said composition has a tack providing agent and/or adhesive at least in part binding the at least one nitrification inhibitor to the particulate zeolite (s).

Preferably but not necessarily the nitrification inhibitor (s) is (are) low water solubility.

Preferably said tack providing agent and/or adhesive is a gum.

Preferably said gum is a polysaccharide gum (e. g. at least one or both of xanthan gum and/or guar gum).

Preferably the composition has a composition of 30 to 70% w/w zeolite (s), 1 to 50% w/w nitrification inhibitor (s), and 0.1 to 5% w/w tack providing agent/adhesive, and optionally 0 to 5% w/w flow enhancing agent.

In a further aspect the present invention consists in a composition of any of the preceding kinds in admixture with a fertiliser.

Preferably said fertiliser is a nitrogen containing fertiliser. In other forms it is or can include trace elements or other fertilising elements.

In another aspect the present invention consists in a fertiliser composition comprising 10 to 80% w/w fertiliser (s), 10 to 70% w/w zeolite (s), 1 to 45% w/w nitrification inhibitor (s), 0.05 to 5% w/w tackifying and/or suspension agent (s) and optionally other inclusion (s) (e. g. flow enhancing agents, etc.).

Preferably the fertiliser is from 50 to 80% w/w of the composition.

The fertiliser may be urea. The urea may be about 60% of the composition.

Preferably the nitrification inhibitor is one or both of DCD and ATS.

Preferably said the composition is formed by any of the methods hereinbefore described and/or hereinafter described with or without reference to any example thereof and/or any of the accompanying drawings.

In still a further aspect the present invention consists in a method of potentiating the nitrification inhibition of a nitrification inhibitor (preferably but optionally selected from one or both of DCD and ATS) which comprises or includes coupling the nitrification inhibitor with a zeolite.

In yet a further aspect the present invention consists in a synergistic nitrification inhibiting composition comprising or including an effective amount of a particulate zeolite carrying an effective amount of at least one nitrification inhibitor.

Preferably the w/w ratio of zeolite (s) to nitrification inhibitor (s) is from 95%/5% to 35%/65% (i. e. 9: 1 to7: 13).

Preferably the nitrification inhibitor is one or both of DCD and ATS.

In still a further aspect the present invention consists in, in a fertiliser delivery system, particulate zeolite (s) carrying (optionally adhered) nitrification inhibitor (s).

In another aspect, as a broadcastable or selectively applicable fertilising composition, (I) liquid and/or solid material (s) having an N and/or other fertilising elemental content together with (II) particulate zeolite (s) carrying a nitrification inhibitor or nitrification inhibitors.

In still another aspect the invention is the use of any composition, fertiliser or product of the present invention on soil and/or pasture.

As used herein the term"zeolite"includes a zeolite of a kind (see attachment) As used herein the term"slurry"is not restrictive to water carried particle mixtures but preferably includes water in the liquid or has water as the sole liquid.

As used herein"nitrification inhibitor (s)" includes one or more inhibitor and preferably, but not only, one of those previously referred to. Examples include - N-2, 5-dichlorophenyl succinamic acid,

2-chloro-6-trichloromethyl pyridine ("Nitrapyrin"), dicyandiamide ("DCD or"DCDIN""), zinc ethylene-bis-dithiocarbamate, 2, 4,6-trichloroaniline, <BR> <BR> <BR> <BR> pentachlorophenol,<BR> <BR> <BR> <BR> <BR> <BR> <BR> thio-urea, ATS (ammonium thiosulphate), and - DMPP (3,4-dimethypyrazole phosphate).

As used herein the term"and/or"means"and"and"or", or both.

As used herein the term"s"following a noun means the singular and plural forms of that noun.

Nothing herein precludes other agents in addition to the nitrification agent (s) also being carried by the zeolite (s).

BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the present invention will now be described with reference to the accompanying drawings in which Figure 1 shows a flow diagram of one form of preparative method in accordance with the present invention leading either to a particulate form having a nitrification inhibitor or inhibitors carried by a particulate carrier or carriers or to a resultant mix thereof with a fertiliser, Figure 2 shows a more specific procedure of which the procedure of Figure 1 is generic, and Figure 3 demonstrates efficacy as explained hereinafter.

DETAILED DESCRIPTION OF THE INVENTION In the preferred form of the present invention the zeolite is of a kind that is preferably with a substantially w/w Mordinite presence (preferably at least 20%, more preferably greater than 40% and most preferably at least 50% e. g. 55 to 95%).

Various aspects of the present invention will now be demonstrated by the following examples which are not limiting of the invention.

Example 1 shows one suitable zeolite form.

Example 1 Composition: Clinoptilolite 25-65% Mordenite 25-65% Smectite <5% Opal C 5-20% K Feldspar 5-20% Density 1.2 g. cm3 Porosity 60% Slurry pH 5.6 CEC 80 meq/lOOg Internal surface area 35 m2/g Colour Opaque Absorbencies Water 55% Oil 45% Example 2 shows a more preferred higher mordenite containing zeolite form.

Example 2 Composition: Mordenite 65-95%

Smectite 5-20% Opal C <5% K Feldspar 5-20% Density 0.89g. cm3 Porosity 60% Slurry pH 5 to 6 for 20% w/v CEC 120 meq/100g Internal surface area 48m2/g Pore size 7 Angstroms Colour Off white Absorbencies Water 55% Oil 45% Examples 3 and 4 show two composition forms where the nitrification agent is DCD alone. Analogous examples can be formed with other nitrification agents disclosed herein or blends of any such agents disclosed herein. The more soluble nitrification agents will be more adsorbed into the zeolite rather than to adhere to the zeolite as is the case with the less soluble nitrification agents.

Example 3-A DCD/Zeolite composition 250 gram DCD (ground until 100% passing 200pm screen) 250 gram Water

Water and DCD were blended until a smooth slurry was formed. To this slurry 5 grams of xanthan gum was added and stirred until fully hydrated (approx 15 min).

The suspension was then added to 500 gram of zeolite (1-3mm) and mixed until the zeolite grains were evenly coated and the mix was the consistency of bread crumbs.

50 grams of talc was then added to form a free flowing, granular DCD product.

Final product contains 23.7% DCD and 0.47% xanthan gum.

The product of Example 3 is a heterogeneous mix of granules typically 1-3mm particle size range. This material is relatively free flowing and is stable in blends with fertilisers.

Example 4-A DCD/Zeolite composition 165 grams of DCD 300 grams of 55% w/w ATS solution DCD and ATS were mixed and blended for 5 minutes with a Silverstone type blender. 4.65 grams of xanthan gum was added and allowed to fully hydrate.

The above mix was added to 470 grams of zeolite (1-3mm) and stirred until bread crumb like granules were formed. The wet granules were dried to yield 800 grams of product.

The product of Example 4 is a heterogeneous mix of granules typically 1-3mm particle size range. This material is relatively free flowing and is stable in blends with fertilisers.

These Example's 3 and 4 products are mixable in all proportions with urea which is the preferred product for delivery to enhance the nitrogen use efficacy of the urea.

Trial Performance The uniform placement of a fertiliser or nitrification inhibitor is most uniform and efficacious if applied as a liquid or suspension.

When applied as a DCD zeolite granule of the present invention (e. g. a composition of Example 3), we have found the granule application surprisingly gave equal or superior efficacy to such liquid or suspension applications as either measured as nitrate or ammonia reduction or expressed as dry matter production.

See Figure 3 in respect of nitrogen losses and Table 1.

This is illustrated from field trial data showing statistically the same efficacy in terms of soil N fractions but a statistically significant advantage in terms of dry matter production.

This may be due to a release characteristic from the zeolite core or an absorption property of the material. In any event, the association with the zeolite in such scenarios of application provide advantages.

Field trials show, almost without exception, at least equality of performance from the particulate (zeolite) application to that of a liquid vehicle application.

The following data presents some results from a range of field trials evaluating the DCD carried in/on zeolite particles when applied dry versus dissolved DCD formulations when applied as a spray, where high nitrogen application rates of order of 600 kg/ha of N have been applied to all treatments.

Pasture measurements were assessed by mowing cuts. DCD N Care trial 1 Woodlands. The granule composition was as in Example 3 Table 1 Form Total yield (kg/ha) Control 1715 Liquid DCD (15 kg DCD/ha) 3194 Zeolite DCD granule (15 kg DCD/ha) 3957 Lsd 294

DCD N Care trial 2 Rotorua. The granule composition was as in Example 3 Table 2 Form Total yield (kg/ha) Control 4254 Zeolite DCD granule (30 kg/ha DCD) 5202 Lsd (5%) 493

DCD N Care trial 3 Ruakura. The granule composition was as in Example 3 Table 3 Form Total leaching (kg N/ha) Control (no urine) 11 Urine 210 Urine plus Zeolite DCD granule (12 kg 145 DCD/ha) Lsd

Table 4 is that table identified as Table 1 in our priority specification (the provisional specification of NZ Patent Application No. 531078). This table shows a range of DCD inhibitor rates and formulations including liquid (DCD L) and their impact on pasture production parameters. Urine was applied at 600 kg N/ha.

Table 4 Treat Form Urine 15. 12.03 15. 01. 04 Total Kg/ha Grass Clover Kg/ha Grass Clover Yield (kg/ha) DM % % DM % % 1 Control 0 641 66.1 30.1 392 52.0 40.3 1715 2 Urea 0 1099 63.3 31.1 508 52.5 38.8 2795 3 Urea + 1771 75.3 20.8 503 67.4 22.3 3301 4 Super U 0 1243 66.8 28.3 384 53.6 39.2 2952 5 Super U + 2104 72.4 17.4 479 65.2 29.2 3852 6 Coated N 0 1168 67.2 29.4 394 58.6 35.0 2877 7 Coated N + 1933 80.3 11.2 637 71.6 21.8 3565 8 DCD (L) 15 + 1827 77.4 18.5 443 73.2 19.7 3194 9 DCD (L) 30 + 1881 76.2 17.0 611 74.9 19.4 3636 10 Zeolite 15 + 2104 77.0 18.7 636 74.7 19.9 3957 11 Zeolite 30 + 2020 75. 3 21.1 618 71.8 16.8 3792 12 Urea 0 988 67.9 27.9 380 54.7 33.9 2356 13 Urea + 2065 76.2 18.4 662 80.7 15.0 3780 *** * *** *** *** SED 182 6.9 5.9 124 7. 3 5.7 294 Contra +-Urine <BR> <BR> <BR> sts<BR> <BR> <BR> <BR> UreavSuperU NS NS NS NS NS t t<BR> <BR> <BR> <BR> <BR> SuperUvCoatedN NS NS NS NS NS NS NS<BR> <BR> <BR> <BR> UreavCoatedN NS NS NS NS NS NS NS<BR> <BR> <BR> <BR> Urine v Super U v Coated N N S N S N S N S N S N S N S Urea v Coated N & Super U N S N S N S N S N S N S N S 2 UreavDCD (all) NS NS NS NS NS NS NS All Super U v Coated N N S N S N S N S N S N S N S with Urine Urea v DCD (Zeolite & Liq DCD) N S N S N S N S N S t N S <BR> <BR> <BR> <BR> <BR> <BR> 30kg/havl5kg/ha NS NS NS NS NS NS NS<BR> <BR> <BR> <BR> Zeolite v Liquid DCD N S N S N S N S N S N S<BR> <BR> <BR> <BR> Interaction N S N S N S N S N S N S N S