NZ242541A - Controlling hieracium species by applying a boron compound or a boron-containing composition - Google Patents

Description

■y »• 4 2425 41 No.: 242541 Date: 29 April 1992 COMPLETE SPECIFICATION "Formulations and use thereof to control Hieracium in Pastureland" We, SOUTHFERT CO-OPERATIVE LIMITED, a company duly incorporated under the laws of New Zealand of Bluff Road, Awarua, Invercargill, New Zealand hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- Hieracium (commonly termed "hawkweeds" in some areas), has become possible the biggest threat to all New Zealand Hill Country. Potentially it is a far greater threat than rabbits. Currently it is devastating millions of hectares of our environmentally sensitive High Country. Various species are now common in the South Island, e.g. Mouse-ear Hawkweed (Hieracium pillosella) is widespread from sea level to 1700 metres (5,500ft) above sea level and across many varied climate zones. Currently it is thought that around six million hectares are affected by Hieracium (Treskonova, M. 1991: Hieracium - an Ecological perspective"Review" Journal of NZ Mountain Lands Institute, December 1991). Areas having dominant cover, i.e. greater than 50% of vegetation are the Molesworth area of Marlborough, inland areas of Mid Canterbury, the Mackenzie Basin and various areas in Central Otago. It is even present in the Hokonui Hills and Takatimu Mountains of Southland.

While the spread of Hieracium throughout Central Otago was widespread by the late 1980s, many of the developed areas "were still holding their own to a large extent". Many fanners in this region were aware that the "patches" of dense Hieracium on the improved Hill Country were rapidly increasing in size. What had been recently 10m2 or half hectare areas, were quickly becoming whole hillsides of Hieracium dominance. Farmers quickly became desperate for some means of control of Hieracium on this type of scale. While many appreciated that being able to "patch" kill Hieracium was not the total answer due to the potentially high seed loading of soils, they felt that such an option must help them retain at least some of their improved country.

Various aspects of research into Hieracium has been carried out for many years now. Little information of any sort however has been available on control of Hieracium except with herbicides. ' • 2.425 Central Otago farmers have commented on various experiences of Hieracium control with the use of fertiliser products, e.g.

Superphosphate (0-9-0) Sulphate of Ammonia, Lime While it appears that in some cases, such products did give some semblance of short term control, the reasons why were sketchy and repeatability appeared to be almost impossible. Some farmers have intended to greatly increase fertiliser usage on Hieracium dominant areas in the hope that the problem would be dramatically diminished.

It has been proven in the past, that with oversowing and topdressing, the effects of Hieracium can be diminished. Most research along these lines has been based around creating competition to retard its aggressive growth habit One of the greatest problems with this policy of "living" with Hieracium, is the climatic patterns experienced in the semi-arid areas. All too often, seasons are unfavourable to promote the necessary vigourous establishment of improved pasture species to compete with Hieracium. Oversowing, fertilising and grazing management are important factors in the long term control of Hieracium but the fact is that the competitive nature of Hieracium itself still remains.

The present invention relates to a method of control that involves the application of a source of boron (for example boric acid or a borate such as sodium borate) in conjunction with (whether admixed therewith or not) one or more fertilising elements to control Hieracium in pasture situations without any significant damage to the pasture species (e.g. clovers and grasses) while severely wilting and thus controlling the Hieracium species. Oversowing with pasture seeds is highly preferred. 9 A 9 H A The present invention, in another aspect, consists in the application of a boron containing compound at a rate sufficient to wilt Hieracium in conjunction with at least one fertilise element that either (i) "safens" the boron application rate from the view point of grasses and/or clovers in proximity to the Hieracium and/or to result from oversowing or (ii) encourages the competitive growth of desired pre-existing or oversown pasture species.

In a further aspect the present invention consists in solution or as a dry or wet mixture, boron containing compound(s) and at least one fertilising element Preferably said control mixture is associated with over sowing either simultaneously therewith, therefore or thereafter.

Preferably at least one fertilising element is one of those elements or compounds or mixtures referred to hereinafter.

Preferably the boron containing compound is a soluble borate such as sodium borate.

Preferably said composition is applied from an aircraft Preferably the rates of boron compound applied are within the range from 25 to 75 kg per hectare when taken as the compound sodium borate pentaxydrate.

In still a further aspect the present invention consists in a mixture of a borate or boric acid and one or more of the following fertiliser elements (Nitrogen, Phosphorous, Potassium, Sulphur, Magnesium, Molybdenum, Calcium as their normal fertiliser compound forms).

In the preferred form of the present invention boron compound is the sodium borate that is known as fertiliser borate available from ICI New Zealand Limited.

Preferably the fertiliser element provided by one or more of Superphosphate, Lime, Sulphate of Ammonia, Urea, Sulphur, Potassium Chloride, Magnesium Oxide, —4.

Sodium Molybdate or Sulphur Agricultural compounds providing the above named fertiliser elements. (N.B. by N.Z. Fertiliser Act. Fertilising elements are e.g. N, P, K etc, fertilisers are Urea, Superphosphate, Potash etc).

Preferred formulations disclosed in the provisional specification were as follows -Example 1 10% Boron, 15% Elemental Sulphur, 75% Superphosphate Example 2 15% Boron, 15% Elemental Sulphur, 70% Superphosphate Example 3 10% Boron, 80.6% Magnesium Superphosphate, 0.4% Sodium Molybdate Example 4 10% Boron, 90% Limestone Example 5 5% Boron, 15% Potash, 79.6% Superphosphate, 0.4% Sodium Molybdate Recommended application rates disclosed in the provisional specification are as follows for each of the compositions of the examples: 1. 250 kg/ha 2. 125 kg/ha 3. 250 kg/ha 4. 300 kg/ha . 500 kg/ha Preferably the oversowing if needed is simultaneously with the treatment and preferably application is from the air.

Preferably the application rate is such that the boron providing compound is applied at a rate of 5 to 25 kg/ha when expressed as a borate anion i.e. B203 and all fertiliser mixtures and/or lime is sown at approximately 250 kg per hectare.

In one aspect the present invention consists in a method of controlling hieracium in pastureland which comprises applying a source of boron to said pastureland to increase the boron soil level available to pasture growth at a level of substantially 3ppm or greater but below levels that are toxic to the pasture grasses. , ^ 2 8 MAR 5994. 242 5 Preferably said boron is applied in the autumn and/or early winter.

Preferably said boron is applied as a borate.

Preferably said borate is applied at a rate which, when expressed as elemental boron, is greater than 2kg/ha.

Preferably the application rate of the boron providing compound, when expressed with respect to elemental boron, is at a rate of about 3.75kg/ha.

Preferably said boron providing compound is applied as sodium borate.

Preferably said boron providing compound is applied to the pastureland in conjunction with at least one fertilising element selected from the group consisting of nitrogen, phosphorous, potassium, sulphur, magnesium, molybdenum and calcium in a fertiliser compound form.

Preferably said boron providing compound and the at least one fertilising element is applied as a mixture/composition.

Preferably said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 79% superphospate, about 11.97% elemental sulphur and about 0.03% sodium molybdate.

Preferably the application rate of the formulation is about 250kg/ha.

Preferably said mixture/composition is (by weight) about 20% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 35% elemental Sulphur and about 45% superphosphate.

Preferably the application rate of the formulation is about 125kg/ha.

Preferably said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 40% elemental sulphur and about 50% superphosphate.

Preferably the application rate of the formulation is about 250kg/ha.

Preferably a said mixture/composition is (by weight) about 20% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 20% elemental sulphur and about 60% superphosphate.

Preferably the application rate of the formulation is about 125kg/ha.

Preferably wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 22% elemental sulphur and about 68% superphosphate.

Preferably the application rate of the mixture/composition is about 250kg/ha.

Preferably wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 90% superphosphate.

Preferably the application rate of the formulation is about 250kg/ha.

Preferably said mixture/composition is (by weight) about 40% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 60% superphosphate.

Preferably the application rate of the mixture/composition is about 250kg/ha.

Preferably said mixture/composition is (by weight) about 40% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 60% superphosphate.

Preferably the application rate of the formulation is about 125kg/ha.

Preferably said mixture/composition is (by weight) about 5% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 12% elemental sulphur and about 83% superphosphate.

Preferably the application rate of the formulation is about 250kg/ha. i L "6 •"=» ^"y Preferably said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% elemental sulphur and about 75% superphosphate.

Preferably the application rate of the formulation is about 250kg/ha.

Preferably said mixture/composition is (by weight) about 15% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% elemental sulphur and about 70% superphosphate.

Preferably the application rate of the formulation is about 125kg/ha.

Preferably said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 80.6% magnesium superphosphate and about 0.4% sodium molybdate.

Preferably wherein the application rate of the formulation is about 250kg/ha.

Preferably said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 90% limestone.

Preferably the application rate of the formulation is about 300kg/ha.

Preferably said mixture/composition is (by weight) about 5% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% potassium chloride, about 79.6% superphosphate and about 0.4% sodium molybdate.

Preferably the application rate of the formulation is about 500kg/ha.

Preferably said borate is fertiliser borate FB48.

In yet a further aspect the present invention consists in a composition comprising (by weight) 10% wet mixed borate compound(s) when expressed as sodium tetraborate pentahydrate, about 79% superphospate, about 11.97% elemental sulphur and about 0.03% sodium molybdate. --8- In yet a further aspect the present invention consists in a composition comprising (by weight) about 20% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 35% elemental sulphur and about 45% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 40% elemental sulphur and about 50% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 20% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 20% elemental sulphur and about 60% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 22% elemental sulphur and about 68% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, and about 90% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 40% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 60% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 40% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 60% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 5% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 12% elemental sulphur and about 83% superphosphate.

In yet a further aspect the present invention comprises a composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% elemental sulphur and about 75% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 15% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% elemental sulphur and about 70% superphosphate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 80.6% magnesium superphosphate and about 0.4% sodium molybdate.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, and about 90% limestone.

In yet a further aspect the present invention consists in a composition comprising (by weight) about 5% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% potassium chloride, about 79.6% superphosphate and about 0.4% sodium molybdate.

Preferably said composition as previously set forth when packaged with instructions to apply the same to a pasture infested or exposed to infestation by hieracium at a rate to increase the boron soil level accessible to pasture growth at a level of substantially 3ppm or greater but below levels that are toxic to the pastures grasses or at a rate which provides the boron providing compound, when expressed with respect to elemental boron, at an application rate of about 3.75kg/ha.

In a further aspect the invention consists in the use of the composition as previously set forth in a method as previously set forth.

Preferably the use as previously set forth is wherein the composition is applied to the pasture from an aircraft Preferably said composition as previously set forth has been formulated by a wet mixing process.

Preferably said method of making a composition as previously set forth when performed substantially as hereinbefore described with or without reference to any example thereof.

With a view to making the invention and proving the invention against other additions, investigations were conducted:- (a) To ascertain if any simple 1 or complex 2 fertiliser or trace element has any direct affect on Hieracium by way of killing or controlling it, and the second:- (b) Duplication of any successful treatment in conjunction with the addition of seeds of "improved" pasture species to replace Hieracium in the medium to long term.

(*Note 1 simple equals fertiliser products containing only one main fertilising element eg Phosphorous. 2 complex equals fertiliser products containing two or more fertilising elements eg Phosphorous plus Sulphur.) Unless stated to the contrary all percentages with respect to mixtures are weight/weight Method fl99(P) Initially all sites selections were based on what would be deemed to be "total" Hieracium (in a farmer's perspective). Actual measurements of vegetation composition of sites were not initially taken. As the main aim was to dramatically decrease the Hieracium component of the sword it was felt that an observational trial was all that was necessary. Any changes would be recorded photographically.

Since the initial site was laid down in December 1990, a large range of sites have been added to the programme.

Small plots The original trial was based around a replicated small plot design using 10m2 plots. All plots would be left unfenced and open to normal grazing management etc. Thirty treatments were initially used based on the following reasoning: 1. A farmer experienced a "killing" affect on Hieracium with the use of Superphosphate (0-9-0-11) at an approximate rate of 750kg/ha. He concluded that Phosphate could be the answer rather than Sulphur which was often promoted (Sulphur being the main fertilising element required in Central Otago). The problem with this rationale was that Superphosphate has more plant available Sulphur than it does Phosphorous. The following questions had to be asked: - (a) Was it in fact the Phosphorous or the Sulphur component that worked or a combination of both? (b) Because of the high rate used, was it purely a "burning" effect due to a high percentage of fines of an acidic fertiliser? Nevertheless 750kg/ha of Superphosphate became the base for the trial design. Three lighter rates were also applied. 2. Because Superphosphate can be regarded as a complex fertiliser (ie more than one fertilising element), it became necessary to isolate and apply the separate elements alone in various forms. Triple Super (0-20-0-1) was chosen as a supplier of Phosphorous only in a readily available form, it was applied at the same rates of P/ha as the three higher rates of Superphosphate. Reactive Phosphate Rock (RPR) (0-14-0-1) was used as a slow release form of Phosphorous only and was also applied at the same rates of P/ha as the three higher rates of Superphosphate.

Some favourable experiences have been noted in the past with applications of Sulphate of Ammonia. This leads to a debate on the practical use of Nitrogen to kill Hieracium and generate more competition from resident pasture species. Therefore D.A.P. (18-20-0-1) was chosen and applied at two rates as a supplier of both Nitrogen and Phosphorous. Sulphate of Ammonia (21-0-0-24) was also applied at two rates, supplying Nitrogen and Sulphur while Urea (46-0-0-0) was applied at one rate for its Nitrogen content only.

Sulphur Supers (S.S.) are commonly used in this region for supplying various rates of Phosphorous and Sulphur. Superphosphate contains Sulphate Sulphur (plant available) only while all Sulphurised Supers supply varying rates of Sulphate Sulphur plus Elemental Sulphur (slow release). As the strength of Sulphur Supers increase, so does the balance of Elemental Sulphur making the high strength Sulphur Supers (e.g. 50% Sulphur Super) slower release products than the low Sulphur Super products (e.g. 22% Sulphur Super).

For these reasons three Sulphur products were chosen, 22% Sulphur Super (0-8-0-22) was applied at three rates as a supplier of equal portions of Sulphate Sulphur and Elemental Sulphur. 50% Sulphur Super (0-5-0-50) was applied at two rates as a slow release Sulphur product (Suggested to meet maintenance requirements based on soil test levels of these areas.) In addition to these, an Elemental Sulphur product known as Durasul (commercially available from Fernz Corp) was applied at two rates as a Elemental Sulphur supplier only. It was felt that the extent of the trial was such that some trace element treatments should be included. These additions were based on various reasoning and included two rates of Sulphate of Iron, one of Fertiliser Borate FB48, one of Zinc Sulphate, one of Hydrated Lime and two rates of Sodium Molybdate.

A control was added (although not necessary as a large area surrounding this plot could serve as a control). Two replicates of each treatment were applied giving a total of sixty plots.

The first site was chosen at Little Valley Station near Alexandra and treated on the 22nd of December 1990. Conditions at the time of treatment were exceptionally dry and this continued throughout the following two months.

In the early New Year (1991), the search for a further site began. The aim was to duplicate the same treatments as before in a higher rainfall climate. To ensure true comparisons, a similarly Hieracium dominant site to that of Little Valley was required. The required site was eventually chosen in early March in the Nevis Valley.

By the end of February 1991, the Little Valley site had failed in its first two months to show effect from any treatment, however in the first week in March a light shower of rain brought a quick response from the Boron treatments with some desiccation of Hieracium leaf in these plots. This response brought about a change to the treatments of the Nevis site.

At this stage it was decided to continue with the main treatments as planned (same as for Little Valley site). The two Molybdenum and one controlled treatments were dropped out allowing room for four rates of Fertiliser Borate (the highest being the same as that used in the Little Valley site). This again meant sixty plots containing two replicates of thirty treatments. (See Appendix 2A). This site was treated on the 25th of March 1991.

Due to the original site only receiving one very high rate of Fertiliser Borate FB48 (here in after referred to as "Borate") treatment (125kg of Borate per hectare), it was decided to treat the two controlled plots at Little Valley with Boron on the 20th of April 1991. One plot had 50kg of Borate per hectare applied and the other 25kg of Borate per hectare.

We then selected another site at Little Valley. Two half hectare plots were marked out and treated using a tractor mounted Vicon spreader on the 13th of June 1991. Plot 1 received 12.5kg/ha of Borate and Plot 2 received 25kg of Borate per hectare. Both plots received a base dressing of 200kg/ha of 33% Sulphur Super. RESULTS The sites at Little Valley were inspected regularly over the Winter months when weather conditions allowed.

Inspection of the two half hectare plots on the 8th of August (only two months after treatment) showed a remarkable colour change in the Hieracium with leaves being bleached and completely desiccated. This was in marked contrast to Hieracium plants outside the treated area. The plot that received 25kg/ha of Borate was showing a superior response to that of the 12.5kg/ha of Borate and similar responses to that of the very high rate (five times higher) used in the original small plot trial (December 1990).

The Nevis site was accessible only once during the Winter period on the 7th of July 1991. At this time only three and a half months after treatment, desirable responses to Borate applications were noted. Visually the 50kg/ha appeared to be giving the same response as 125kg/ha and 25kg/ha was close behind. Once again, responses to 12.5kg/ha appeared to be minimal. These responses were recorded photographically.

As Spring growth conditions began in late September, all Boron treated plots including the high rate of 125kg/ha of Borate began to show signs of Hieracium re- 24^54 growth. This was of concern to the project as ultimately a possible treatment must show signs of medium to long term control.

Some areas of treated Hieracium were extracted and soil washed from the dense root system. Re-growth appeared to be occurring from the very end of what otherwise appeared to be dead stolons. This young growth was sending down a new root system into the soil below. From a 225cm2 section (6in x 6in), 19 young plants were extracted in such a way.

The cause of this re-growth was, to an extent, a mystery. Soil samples were taken for Boron tests (Hot Water Extractable Boron) on the 27th of September 1991. The half hectare plots that received 25kg/ha of Borate and 12.5kg/ha of Borate yielded levels of 7.32ppms and 4.51ppm respectively compared with a pretreatment level of 0.98ppms. Why was Hieracium re-growing if it was truly susceptible to Boron? Because of the noted lack of response in the Summer/Autumn 1991 trials (in accordance with the trial aims) from all treatments, except that of Boron, it was decided to concentrate further trials and research around Boron alone.

In accordance with the second main aim of the trial, i.e. duplication and replacement, a Spring 1991 Trial Programme was put in place.

We were pleased with the promise that the half hectare scale plots had shown and therefor wanted to continue with them as they were closer to a commercial scale than that of the 10m2 plots. It was necessary to also repeat the small plot design in order to maintain a reasonable level of control.

In early August 1991, two sites were selected in the Omarama area for the use of half hectare plots. --16- The first site (Croft) was chosen for its heavy Hieracium cover and because it had been overdrilled and topdressed a number of years ago with little apparent success.

The second site was chosen for its dominance of Kingdevil Hawkweed (Hieracium praealtum). This was an important choice, as to date all previous sites had displayed only Mouse-ear Hieracium. This site had also had a recent history of topdressing and oversowing in the past On both sites five half hectare plots were marked out and treated. The following treatments were selected:-(see also Appendix 2B) 1. Control = 200kg/ha of 22% S.S. plus 0 Borate 2. 200kg/ha of 22% S.S. plus 6.25kg Borate/ha 3. 200kg/ha of 22% S.S. plus 12.5kg Borate/ha 4. 200kg/ha of 22% S.S. plus 25kg Borate/ha . 200kg/ha of 22% S.S. plus 50kg Borate/ha These sites were treated on the 7th of August 1991 and 16th of August 1991 respectively. Treatments were applied with the use of a C-Dax Fertiliser Spreader mounted on a four wheel motorbike.

Added at each of these sites were a set of smaller plots (25m2 each) being treated each with one of the above rates of Boron plus 22% Sulphur Super. This was done for the sake of precision and comparison if necessary in future.

A duplication of the original two half hectare plots at Little Valley was made on 26 September. These two plots also received 200kg/ha of 33% Sulphur Super plus Borate at the rates of 12.5kg/ha and 25kg/ha applied with the motorbike mounted spreader. 2425 The first of the Spring small plot trials was sited on another Omarama property. This site was regarded as being previously unimproved, (i.e. no fertiliser or oversowing history). Hieracium, especially Kingdevil and Mouse-ear were prevalent with much bare ground.

Boron was applied to all plots with a range of four rates (same as used in half hectare plots). Boron was to be applied by itself, with Superphosphate, 22% Sulphur Super, 50% Sulphur Super and Lime giving twenty treatments. Two replicates of each treatment were laid down giving a total of forty plots. (See Appendix 2A for treatment rates.) The large area around the site would be sufficient to act as a control. Treatments were applied on the 10th of September 1991.

In addition to the fertiliser treatments, all plots within Replicate 2 were oversown (by hand) with a pasture seed mix of: 2kg/ha Tahora White Clover 2kg/ha of Alsike 2kg/ha of Cocksfoot This seed mix was applied the same day as the fertiliser treatments and was based around the "normal" seed mix and rate used for oversowing in the area.

A further plot was added of 5m x 20m to which the seed mix along was applied. This may have been necessary to help distinguish any variances in germination, e.g. to Boron additions (which can be expected) or purely seasonal influences.

Another small plot design site was laid down at Little Valley on the 26th of September 1991. This was of identical design to that just outlined at Omarama, except control plots were incorporated in the design due to varying vegetation cover outside of the site area.

A further replication of the above small plot trial was sited in the Nevis Valley. It was treated on the 7th of October 1991.

The aim of these three sites was to test the same treatments on varying soil types and climate zones.

To help fulfil the main aim of replacement, seed was applied to Replicate 2 of the original small plot trial (Dec 1990) at Little Valley on the 26th of September 1991. Half of each plot within the Replicate was direct drilled while the other half was oversown.

Results Results from this round of treatments and period, (i.e. Spring/Early Summer 1991) were disappointing to say the least Visually there appeared to be no response at all at any of the sites. Regular inspection of sites until Christmas time failed to show any change.

The half hectare plots treated in August at Omarama had up to 50mm of rain within 10 days of treatment Possibly leaching of Boron out of the root zone was debated. Soil samples were taken from each of the treatments at the first Omarama site on the 21st of October and the following Hot Water Extractable Boron levels were found: - Control (zero Boron) 0.82ppm 6.25kg/ha of Borate 1.65ppm 12.5kg/ha of Borate 1.78ppm 25kg/ha of Borate 1.80ppm 50kg/ha of Borate 2.93ppm While these results show that the soil Boron level increased with the increasing addition rate, the highest level was still well below that obtained from the Little Valley 242 5 4 sites back on the 27th of September. One could suggest that this was due to the rainfall, however Little Valley also experienced similar levels of rain over the same period.

This experience in conjunction with the Spring re-growth of Hieracium in the Autumn treated plots was concerning. However some hope was held in the fact that soil Boron levels were still higher than pretreatment (in Autumn applied plots). A key role of duplication in different seasons, was to establish if there were seasonal variations and therefore ideal timing of application. It was hoped at this stage that Hieracium may display some possible physiological change with time of year and therefore re-growth may decline again later in the season.

On the positive side, germination of introduced grasses and legume species was particularly pleasing. This was somewhat unexpected (especially at high Boron rates) as Boron is commonly regarded as being toxic to germinating seedlings. The small plots at Omarama, which had seed oversown on the same day as Boron treatment, showed remarkable levels of germination, especially considering the very dry nature of the period after application. Visual assessment of these plots concluded that seed germination was as good in the plots that received 50kg/ha of Borate (highest rate used in this trial) as it was on the lowest rate of 6.25kg/ha of Borate. The same conclusions were also reflected in the comparison between the Boron plots and the plot that had seed only (no Boron).

Seedling establishment beyond germination however (regardless of treatment) was not particularly good, due mainly to climatic patterns of the time. We conclude from this experience that a combination of earlier seeding and a higher seeding rate is necessary in such situations.

Assessment of seed germination and establishment on the same trial design at Little Valley was impossible due to a large increase in production from existing pasture species, especially annual grasses and legumes in response to timely rainfall.

The same problem occurred with the oversowing portion of the original Little Valley site. However the response from the direct drilling portion was spectacular. In all treatments except that of Boron, introduced seedlings (direct Drilled) struggled with the severe competition. Those plots that had received Boron showed a marked contrast with, especially, legumes well established.

This response was recorded photographically on the 4th of March 1992. In reflection this would appear to be a result of reducing the severe competition for available moisture rather than a direct response of the introduced species to the Boron itself. The exceptionally high rate of 125kg/ha of Borate (even though not recommended) certainly had no adverse effect on seed germination and establishment in this trial where seed was introduced nine months after the initial Boron application. AUTUMN 1992 Inspection of sites in February/early March revealed that regrowth in the earlier plots (Summer/Autumn 1991) was in fact reversing and going through a very similar regression to which was experienced at the time of original application. This appears to suggest Hieracium may go through physiological changes which make it more susceptible to Boron applications in the Autumn and early Winter months. It also suggests that a Boron treatment is likely to have some ongoing effect at least beyond one season.

In the late Autumn, some of the sites that were Spring treated, also showed some similar signs but not to the same extent as the Autumn applied treatments had. ■ ■ 242 5 These new developments brought the whole programme to a critical point Ideally another season of small plots were necessary to confirm current trends. However time was lacking for many thousands of hectares being effected by Hieracium. The scale of the programme was, therefore, rapidly expanded.

Methods Again a small plot trial programme was carried out in the Autumn (1992) in order to ensure continual control and assessment Four rates of Borate was used, 12.5kg/ha, 25kg/ha, 50kg/ha and lOOkg/ha applied alone and in conjunction with 200kg/ha of 22% Sulphur Super (see Appendix 2A for treatments). Two replicates of each treatment gave a total of 16 plots.

This trial design was replicated at the three previous properties at Little Valley, Nevis Valley and Omarama. Treatments were applied between the 7th and 9th of April 1992.

The two half hectare plot sites at Omarama had a further four half hectare plots added to each using a control plot plus three rates of Boron, i.e. 12.5, 25 and 50kg Borate/ha, all with a basal dressing of 200kg/ha of 22% Sulphur Super (see Appendix 2B). These were treated on the 21st of May 1992.

A larger scale trial programme was set up for late March 1992. In addition to the original trial aims, this programme had two purposes:- 1. To attempt to duplicate favourable results to date on a commercial scale. The choice of sites that were used for this aim, were based on severe Hieracium infestation (on a large scale, 20-40ha), spread of rainfall patterns and soil types and varying altitudes. 2. To ascertain if Hieracium can be kept out of large areas yet to be infested by Hieracium by applying a light rate of Boron on a regular basis. The choice of u4^ sites for this purpose was based on size (40ha) and the sites being in close proximity to already severe Hieracium infestation without containing predominant Hieracium itself.

The sites that were chosen were:- (a) Little Valley, Alexandra 20ha (b) Little Valley, Alexandra 40ha (c) Beaumont Station/Taieri Headwaters 40ha (d) R. Hill/Millers Flat area 20ha (e) R. Hill/Millers Flat area 20ha (f) Morven Hills Station/Lindis Pass 20ha (g) Nokomai Station/Nevis Valley 40ha Total 200ha (500 acres) (see Appendix 1 for more detailed site description and Appendix 2C and 2D for treatments) Each site had varying aspects, degree of slopes, and pasture cover. All treatments were applied by fixed wing aircraft in a normal commercial manner, the intent being to measure both the response on a commercial scale compared with small plot trials as well as to objectively measure and visually assess any variation and response within each site due to differing degrees of slope, aspect, vegetation, spread patterns etc.

The two Little Valley sites and two Millers Flat sites had had a history of oversowing and topdressing, therefore it was not expected to have to re-seed these sites. 1 24254 The Beaumont site had no history of fertiliser but had been oversown with seed eight months previously.

The Morven Hills and Nokomai sites were both native therefore seed was oversown on the 6th of September and the 13th of September respectively. The seed mixture consisting of Tahora White Clover, Alsike, Wana Cocksfoot and Massy Bassyn at a combined rate of 12kg/ha.

Objective measurement (due to some expected variation) became necessary on plots of this scale. This measurement process would be repeated 12 months after treatment to assess any changes.

It was hoped to have a large scale site (20ha plus) of predominantly Hieracium at a greater annual rainfall than we have, e.g. 1200-1700mm. This however was not possible. While Hieracium is certainly present in such rainfall regions, it was not possible to locate a suitably accessable site of this scale.

We therefore compromised and laid down five small plots (10m2) in the Rees Valley area, Glenorchy, on an area of Mouse-ear Hieracium. This site was treated on the 18th of May 1992.

Results Generally the results from the small plots applied in Autumn 1992 have been similar to that of Autumn 1991 except for the general observation that it appears a greater rate of Borate per hectare was required this season to get a similar response to last season. The small plot sites at Little Valley, Nevis and Omarama (T) all showed exceptional results from the application of 100kg Borate/ha (very little Hieracium has remained in these plots). The application of 50kg/ha Borate showed a medium response in reducing plant numbers while 25 and 12.5kg Borate/ha showed little response this season. Winter and Spring Conditions (1992) were damper and cooler than 1991 and growth was approximately three weeks later in the Spring. A question that arises from this is the effect that varying seasonal patterns may have on Boron as a treatment On all sites (as experienced in previous sites), there was no difference in responses between that of Borate plus 22% Sulphur Super and Borate alone. This confirms that Boron is itself the active ingredient The five small plots at Rees Valley also showed similar responses to the above, i.e. increasing response with increasing strength, however lOOkg/ha showed less response than it did in the other three sites. This is likely due to two reasons:- 1. Again rainfall - this site is substantially higher rainfall than all other sites. 2. Topography - this site is on a very steep slope compared with the flat sites of Little Valley and Omarama (T). Some evidence of response below the pegged plots at Rees Valley suggests the movement of Borate down the slope. Some small evidence of movement with slope is also apparent on the less steep Nevis site.

The commercial scale plots (20 & 40ha plots) that received 25kg/ha Borate have yielded mixed results. Little Valley (Site 10) has shown the best results to date.

Results within this 20ha plot vary from no response to what appears to be very good control. There was a marked difference during the spring between Hieracium still present within this plot and that outside the plot (control). Hieracium outside the plot appeared far more active in its growth patterns.

Inside this plot the best responses tended to be found on the flatter area near the top of the site and in the ruts where water movement had been channelled. Generally the steeper slopes showed poorer responses although there was a steep sloped area that showed a very favourable response.

The Lindis site (Site 14) showed favourable responses on the flat area and lower (gentle) fan slopes early in the season but those were quickly masked by regrowth of especially Hieracium praealtum. The very steep slopes of the main ridge in this plot tended to show no response.

The Millers Flat Site that received the high rate of Boron (Site 12b) showed early signs of favourable results but this was also quickly masked by some regrowth of Hieracium and especially growth of the improved pasture species that were present It was not possible to inspect the Beaumont (Site 13) and Nokamai (Site 18) sites until November/December 1992 by which time spring growth was well advanced. Responses to the applied Boron could be found in some areas however as with the other sites, the spring growth was likely masking the earlier effects.

Generally the results from these large plots (with the exception of Little Valley) have been disappointing. Across all sites there appears to be variation in results, possibly due to varying rainfall patterns and topography. On a commercial scale slope plays a bit factor. In all examples, fertiliser treatments are applied by air on a "flat survey" basis. Areas of flat topography therefore receive the required application rate but intermediate and especially steep slopes could receive substantially less than desirable due to a greater "true area". This in conjunction with an potential run off factor, could explain the variations in results with changing topography.

It is hoped that the followup analysis of the objective measurements of the Little Valley and Lindis sites (results due April/May 1993), will help measure any relative change in plant compositions and cover compared with pre-treatment The two sites one at Little Valley (Site 11) and one at Millers Flat (Site 12a), that received the low Boron treatments (6.25kg Borate/ha) will be monitored over time for any increase in Hieracium cover. 242 5 4 The l/2ha sites, Sites 20 & 21 (Omarama(C) & Omarama(W)) again have been disappointing in their response. This may be due to purely seasonal variations or differences in the site itself compared with the original l/2ha sites at Little Valley. Both of the above sites were soil tested for Boron pretreatment giving levels of 0-94ppm and 2.18ppm respectively (Omarama(W) tested higher than expected). Both sites were retested on the 18 December 1992 and gave the levels of 2.58ppm and 2.34ppm respectively. These levels are in contrast to 6.28ppm received from lOOkg/ha Borate plots on the Omarama(T) site (Site 16) on the same day (18/12/92). These variances are similar to those experienced in the past.

We believe a "critical" soil boron level must be obtained before responses in Hieracium occurs eg. 3-4ppm.

Trial Conclusions - To date - January 1993 1. Boron adversely affects the vigour and survival of Hieracium compared with many other plants, especially "improved" pasture species. It appears that Hieracium is less tolerant, compared with other plants, to levels of Boron that are higher than normal. 2. Out of many fertilising elements trialed Fertiliser Boron FB48 was the only treatment to directly control and, in cases kill Hieracium. However, other boron combinations with a fertiliser can be manufactured. 3. Best results are obtained from an Autumn/early Winter application of Boron. 4. Survival of existing pasture species and the establishment of new species is possible using a far greater application rate of Boron than would be expected.

. Responses to Borate applications on a commercial scale can be variable due to various influences such as seasonal climatic patterns, topography, method of application etc.

"Wet Mixed" Borated Fertilisers Southfert normally add Fertiliser Borate to base fertiliser products, when required, by "dry mixing" Borate with Fertiliser at dispatch. This normally entails passing base fertiliser over a weigh feeding system thereby automatically adding the required Borate/t in a dry "as received" form. This means that the Borate is part of the mixture but able to segregate from the bigger fertiliser particles that it is mixed with. It is not a "homogeneous" mix, i.e. Boron is not contained within every fertiliser particle. To the best of our knowledge, the above process is normal for the whole of the fertiliser industry in New Zealand.

The Hieracium trials showed that it was important to touch each plant at a sufficient rate in order to control it The problem with "dry mixed" borated products is that separation of the fine Borate from the granular fertiliser it is mixed with, can occur in both transit and application giving an uneven spread of the "active ingredient" on the ground.

It was also experienced that mixtures containing 10% Borate addition or more displayed adverse keeping characteristics, i.e. products tended to "set up" and go lumpy. The more Borate that was added, the greater the problem.

It therefore became necessary to produce a product that met the following requirements: 1. A product that contained B in all particles of the fertiliser mix to prevent segregation and therefore achieve as even a spread as possible. 2. To produce a high Borated product that was more stable.

An option was to "wet mix" the Borate. Wet mixing of some trace elements, e.g. Molybdenum is common. In the case of Mol because the standard addition rate (300gms Sodium Molybdate/t) is so small, it is easy and advantageous for evenness of ' ' 24254 mixing, to dilute the Mo in water and spray on to fertiliser product. In the case of Boron where we need to add in excess of 50kg Fertiliser Borate/t, wet mixing in such a way is not possible due to the extreme amount of liquid that would be required.

Instead, modifications to the manufacturing plant were made to allow the Borate to be added at the "ex-Den" stage instead of the normal dispatch stage. This meant that the Borate was added to the "raw" Superphosphate etc and was mixed throughout the product prior to going through the granulating process (see Figure 1 appended hereto).

The manufactured "wet mixed" product from this trial production, was used in the large scale plots that received the high rate of Boron, i.e. Sites 10,12a, 13, 14 & 18, Sites 11 & 12a received a low rate of Boron supplied by a "dry mixed" product In both cases the pilots involved were asked to pick which of the lines were high Boron and which were low Boron containing fertilisers. In both cases the pilots believed the high Boron products were in fact the low Boron products. This demonstrates the success in stabilising the physical characteristics of a high Boron product by wet mixing. The high Boron products had four times more Boron content than the low Boron products.

The Synergistic Effect The trials to date have shown that out of all the fertilising elements trialed, Boron is the only one to have a major physical effect on the species Hieracium. Many people in the recent past however have shown concern that if the prominence of Hieracium dramatically declined by way of either natural and or human influences then we may be faced with a far greater problem of massive soil erosion. Therefore 4 2 R 4. 14 i' research into Hieracium control must include measures that will transform the land into a better state than it currently is.

To this end the Southfert trials and general field experience has helped to formulate the following "preferred formulation" for the purpose of Hieracium control: 10% wet mixed Fertiliser Borate FB48, 79% Superphosphate 11.97% Elemental Sulphur, 0.03% Sodium Molybdate Recommended application rate of 250kg/ha is such that the Boron providing compound is applied at a rate of 3.75kg Elemental Boron/ha.

A range of Boron application rates, outside that of the "preferred formulation" could be used from 10kg Borate/ha to 100kg Borate/ha (1.5-15kg Boron/ha). Because base nutrient requirements (e.g. requirement for N, P, K, S, Ca etc) will differ for many reasons, e.g. soil type, climate, stocking rate etc, the above range of Boron applications could be mixed with any base fertiliser product containing one or more of Nitrogen, Phosphorous, Potassium, Sulphur and Calcium (including Limestone). The Borate could be added to such "base" products by wet mixing or the conventional dry mixing process. The list of possible "base" products is essentially infinite (thousands) however a list of some of the more likely mixes are listed below.

Recommended Sowing Rates Preferred formulation: % wet mixed Fertiliser Borate FB48, 79% Superphosphate, 11.97% Elemental Sulphur, 0.03% Sodium Molybdate 250kg/ha Alternatives 1. 20% Borate, 35% Elemental Sulphur 45% Superphosphate 125kg/ha / k) r* / /n / *- J ^ 250kg/ha 2. 10% Borate, 40% Elemental Sulphur 50% Superphosphate 3. 20% Borate, 20% Elemental Sulphur 60% Superphosphate 125kg/ha 4. 10% Borate, 22% Elemental Sulphur 68% Superphosphate 250kg/ha . 10% Borate, 90% Superphosphate 250kg/ha 6. 40% Borate, 60% Superphosphate 250kg/ha 7. 40% Borate, 60% Superphosphate 125kg/ha 8. 5% Borate, 12% Elemental Sulphur 83% Superphosphate 250kg/ha 9. 10% Borate, 15% Elemental Sulphur 75% Superphosphate 250kg/ha . 15% Borate, 15% Elemental Sulphur 70% Superphosphate 125kg/ha 11. 10% Borate, 80.6% Magnesium Superphosphate 0.4% Sodium Molybdate 250kg/ha 12. 10% Borate, 90% Limestone 300kg/ha 13. 5% Borate, 15% Potassium Chloride, 79.6% Superphosphate, 0.4% Sodium Molybdate 500kg/ha Reasoning The trials show that an application of 25kg/ha of Fertiliser Borate FB48 gives the best combination of economic and agronomic effects on Hieracium.

The Boron component is the sole "active ingredient" for the purpose of controlling Hieracium in the above "preferred" and any other formulations. -■-31- The Superphosphate plus molten mixed Elemental Sulphur (combined are commonly known as 22% Sulphur Super) forms the base material for the above formulation. The main purpose of this is to supply the "ideal" balance of plant available Phosphorous and Sulphur (from Superphosphate) and "slow release" Sulphur (from Elemental Sulphur). Plant available P & S are essential for the establishment of improved pasture species, e.g. White Qover, Red Qover, Cocksfoot, Alsike Cover, Lotus etc in order to replace the controlled Hieracium while "slow release" Sulphur is essential for ongoing vigour of these species, especially the legumes, e.g. White Qover, Red Clover, Alsike.

The added Sodium Molybdate is essentially for the Rizobia Bacteria contained in the nodules of Legume Roots, to "fix" Nitrogen from the atmosphere and make it available for use by other plant species.

The application of Superphosphate and Elemental Sulphur (22% S.S.) with or without Sodium Molybdate is common practice in much of the "improved" Hill Country of the South Island. However the combination of these with Boron would be very rare in this class of country.

Timing of Application The trials have strongly suggested that an Autumn/early Winter (Feb-May) application of Boron to Hieracium is most effective. Spring applications have not been as favourable. It is not fully understood why this may occur. One possibly reason is a physiological change in the Hieracium plant itself making it more susceptible to Boron poisoning at a certain growth phase, e.g. post flowering.

Flowering normally occurs in the months of November-January. I understand fruit trees in Central Otago show these types of changes with growth stage. >4^5 4 Therefore the "preferred formulation" or any other used for this purpose, would be best applied in the months of February to May to control Hieracium.

Seeds of improved pasture species, e.g. White Clover, Red Qover, Alsike, Cocksfoot should preferably be applied separately in the Spring following treatment, e.g. August/September for the following reasons: 1. Studies show that Hieracium species (especially Hieracium pillosella) produce phenolic acids which affect the establishment and growth of species such as White Clover (process termed "Allelopathy"). Some studies show that these acids are released only from dead leaves. Furthermore, these acids are leached from such leaves quickly therefore creating only a short term problem (Makepeace pages 89-122). By treating Hieracium with Boron in the Autumn period and then applying seed in the Spring would allow Winter rainfall to leach any phenolic acids from the dead leaves and therefore present less risk to germinating seedlings. 2. Winter rainfall will also have the tendency to dilute soil Boron concentrations which in turn would pose less risk to young seedlings of Boron toxicity (not experienced to a high degree in trials).

Fertiliser Application The "preferred method" of application of the "preferred formulation" or any other formulation would be "ground spread by means of a ground operated bulkspreader". An alternative to this would be aerial application by fixed wing aircraft or helicopter. The said mixtures should not be sown down the spout of a drill in contact with seeds due to the potential toxic effect of Boron on seedlings.

Reasons - Ground spreading tends to offer the best control over evenness of spread of the products involved. Evenness of spread is critical to success as trials have --33- ' ' 2425 4 shown that if plants are missed by the treatment, then they will remain. Ground spreading allows for better targeting of isolated areas.

It is not possible to access and operate ground machinery on much of the Hieracium problem areas. Therefore aerial applications of some form or another is important This however creates associated problems as experienced in the large scale trial plots (20ha and 40ha). On this larger scale "stripping" of product is common due to flying patterns and uneven distribution of fertiliser particles (which cover a range of sizes) from the aircraft's hopper. This means some areas receive greater than the desired rate while other areas may not receive any. Compounding on this is the topography typically involved with this method. Groundspreading due to limitation is carried out on more gentle slopes than is aerial application. With aerial application in reality, the treatment is spread on a "flat survey" over country that varies dramatically from flat areas to gentle slopes to very steep slopes. Because the treatment is based on a "flat survey" only, the flatter areas receive the desired application rate. Very steep areas can receive appreciably less than desired consequently with expected results. (This type of trend was experienced on the large scale plots.) Seed Application Ideally seed should be drilled into the soil using "minimum cultivation" type techniques. This would allow for best possible establishment of seedlings in the treated area. Again the normal practice of aerial application of seeds will be necessary in many cases especially where it is not possibly to use ground operated machinery. Seeding rates in such cases may need to be increased in such situations. Both methods were used in trials with success.

Appendix 1 Site Descriptions Site 1. Little Valley Soil Type:- Blackstone Hill (YGE) Pretreatment soil test levels:- pH Olsen P Sulphate S .6 48 9 Annual Rainfall:- 350mm Vegitation:- Predominantly Hieracium, previously oversown and topdressed. Altitude/Aspect:- 670m, shady flat aspect Treated:- 22 December 1990 Plot Size:- 60 * 10m2 Site 2 Nevis Soil Type:- Arrow (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S .1 37 2 Annual Rainfall:- 875mm Vegetation:- Predominant Hieracium, Native Altitude/Aspect:- 770m, Sunny aspect 0-2S° slope Treated:- 25 March 1991 Plot Size:- 60 * 10m2 " Site 3 Little Valley Soil Type:- Blackstone Hill (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Annual Rainfall:- 350mm Vegetation:- Predominant Hieracium, previously developed Altitude/Aspect:- Shadey 0-3° Treated:- 13 June 1991 Plot Size:- 2 * 0.5ha Site 4 Omarama (C) Soil Type:- Dalgety (Upland YBE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .8 30 8 0.77 Annual Rainfall:- 600mm Vegetation:- Predominant Hieracium, previously topdressed and Overdrilled Altitude/Aspect:- , flat Treated:- 7 August 1991 Plot Size:- 5 * 0.5ha plus 4 * 25m2 Site 5 Omarama ("W"! Soil Type:- MacKenzie (Upland YBE) ^^Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron 5.7 30 7 0.55 Annual Rainfall:- 550mm Vegetation:- Predominant Hieracium, previously oversown and topdressed Altitude/Aspect:- ,flat Treated:- 16 August 1991 Plot Size:- 5 * 0.5ha plus 4 * 25m2 t £, q, Site 6 Omarama (T) Soil Type:- Acheron (Upland YBE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .5 24 3 0.72 Annual Rainfall:- 600mm Vegetation:- Predominant Hieracium, Native Altitude/Aspect:- , flat Treated:-10 September 1991 Plot Size:- 44 * 10m2 Site 7 Little Vallev Soil Type:- Blackstone Hill (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron --37- 2 .6 44 11 0.72 Annual Rainfall:- 350mm Vegetation:- Hieracium, Browntop, Native (undeveloped) Altitude/Aspect:- 650m, flat Treated:- 26 September 1991 Plot Size:- 44 * 10m2 Site 8 Little Vallev Soil Type:- Arrow (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .7 31 20 1.35 Annual Rainfall:- 350mm Vegetation:- Predominant Hieracium, Browntop, previously oversown and topdressed Altitude/Aspect:- 700m, shadey 2-3° slope Treated:- 26 September 1991 Plot Size:- 2 * 0.5ha Site 9 Nevis Soil Type:- Arrow (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S .5 36 2 Annual Rainfall:- 875mm Vegetation:- Predominant Hieracium, Native 4254 m*. r tta qJI ^Altitude/Aspect:- 770m, Sunny slope 15-20° Treated:- 7 October 1991 Plot Size:- 40 * 10m2 Site 10 Little Valley Soil Type:- Arrow (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Annual Rainfall:- 350mm Vegeitation:- Predominant Hieracium, previously oversown and topdressed Altitude/Aspect:- 700m, Dark facing, 1-30° slope with sunny and dark ridges Treated:- 26 March 1992 Plot Size:- 1 * 20ha Site 11 Little Valley Soil Type:- Arrow (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Annual Rainfall:- 325mm Vegetation:- Browntop etc, Previously topdressed Altitude/Aspect:- 460m, flat Treated:- 26 March 1992 Plot Size:- 1 * 40ha ite 12 Millers Flat Soil Type:- Arrow (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Annual Rainfall:- Vegetation:- Improved oversown Tussock with Some Hieracium Altitude/Aspect:- Sunny 0-15° slope Treated:- 30 March 1992 Plot Size:- 2 * 20ha Site 13 Beaumont Station Soil Type:- Teviot (Upland YBE) Pre-treatment soil test levels: - pH Olsen P Sulphate S Annual Rainfall:- Vegetation:- Native Tussock with some Hieracium Altitude/Aspect:- Sunny 0-10° slope Treated:- 30 March 1992 Plot Size:- 1 * 40ha Site 14 Lindas Soil Type:- Cass (Upland YBE) 're-treatment soil test levels:- pH Olsen P Sulphate S Annual Rainfall Vegetation:- Native Tussock with Hieracium Altitude/Aspect:- 950m, Sunny 3-30° slope Treated:-1 April 1992 Plot Size:-1 * 20ha Site 15 Little Valley Soil Type:- Blackstone Hill (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .4 28 9 1.52 Annual Rainfall:- 350mm Vegetation:- Hieracium, White Qover, Browntop, previously overdrilled and topdressed Altitude/Aspect:- 670m, shady flat aspect Treated:- 7 April 1992 Plot Size:- 16 * 10m2 Site 16 Omarama (T) Soil Type:- Acheron (Upland YBE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .2 29 4 1.06 Annual Rainfall:- 600mm Vegetation:- Pedominant Hieracium, Native Altitude/Aspect:- , flat Treated:- 7 April 1992 Plot Size:-16 * 10m2 Site 17 Nevis Soil Type:- Arrow (YGE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .2 30 2 1.02 Annual Rainfall:- 875mm Vegetation:- Predominant Hieracium, Native Altitude/Aspect:- 770m, Sunny slope 15-20° Treated:- 9 April 1992 Plot Size:- 16 * 10m2 Site 18 Nokamai Station Soil Type:- Dunstan (Upland YBE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron Annual Rainfall:- a & z ^ wvegetation:- Native Tussock with Some Dominant Hieracium B Altitude/Aspect:- 850m, sunny 15-30° slope Treated:-11 April 1992 Plot Size:- 1 * 40ha Site 19 Rees Valley Soil Type:- Haast (High Country Podzolised YBE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .1 10 2 0.66 Annual Rainfall:- 1750mm Vegetation:- Hieracium, Native vegetaion Altitude/Aspect:- Dark 20-30° slope Treated:-18 May 1992 Plot Size:- 5 * 10m2 Site 20 Omarama (C) Soil Type:- Dalgety (Upland YBE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .8 25 2 0.94 Annual Rainfall:- 600mm Vegetation:- Predominant Hieracium, previously topdressed and overdrilled Altitude/Aspect:- Flat Treated:- 20 May 1992 --43- ®Plot Size:- 4 * 0.5ha Site 21 Omarama (W) Soil Type:- MacKenzie (Upland YBE) Pre-treatment soil test levels:- pH Olsen P Sulphate S Boron .5 31 6 2.18 Annual Rainfall:- 550mm Vegetation:- Predominant Hieracium, previously oversown and topdressed Altitude/Aspect:- m, flat Treated:- 21 May 1992 Plot Size:- 4 * 0.5ha ^APPENDIX 2A Small Plot Sites (10m2) Site 1 - Little Valley Treated 22/12/90 - seed applied 26/09/91 (replicate 2 only) Treatment 1 " 0-9-0 @ 125kg/ha 2 0-9-0 @ 250kg/ha 3 0-9-0 @ 500kg/ha 4 0-9-0 @ 750kg/ha Triple Super @ 105kg/ha 6 Triple Super @ 210kg/ha 7 Triple Super @ 320kg/ha 8 R.P.R. @ 152kg/ha 9 R.P.R. @ 304kg/ha R.P.R. @ 455kg/ha 11 D.AP. @ 250kg/ha 12 D.AP. @ 500kg/ha 13 Sulphate of Ammonia @ 250kg/ha 14 Sulphate of Ammonia @ 500kg/ha Urea @ 125kg/ha ^^16 22% Sulphur Super @ 250kg/ha 17 22% Sulphur Super @ 375kg/ha 18 22% Sulphur Super @ 500kg/ha 19 50% Sulphur Super @ 250kg/ha 50% Sulphur Super @ 500kg/ha 21 Durasul @ 125kg/ha 22 Durasul @ 250kg/ha 23 Sulphate of Iron @ 125kg/ha 24 Sulphate of Iron @ 250kg/ha Fertiliser Borate @ 125kg/ha 26 Zinc Sulphate @ 125kg/ha 27 Hydrated Lime @ 250kg/ha 28 Molybdenum @ 150gms/ha 29 Molybdenum @ 300gms/ha Fertiliser Borate @ 25kg/ha and 50kg/ha (20/04/91) Site 2 - Nevis Treated 25/03/91 —46- - seed applied 07/10/91 (replicate 1 only) Treatment 1 0-9-0 @ 125kg/ha 2 0-9-0 @ 250kg/ha 3 4 ' 6 7 ^54 0-9-0 @ 500kg/ha 0-9-0 @ 750kg/ha Triple Super @ 105kg/ha Triple Super @ 210kg/ha Triple Super @ 320kg/ha 8 9 R.P.R. R.P.R. R.P.R. @ @ @ 152kg/ha 304kg/ha 455kg/ha 11 12 D.A.P. D.AP. @ 250kg/ha 500kg/ha 13 Sulphate of Ammonia @ 250kg/ha 14 Sulphate of Ammonia @ 500kg/ha Urea @ 125kg/ha 16 17 22% Sulphur Super @ 250kg/ha 22% Sulphur Super @ 375kg/ha —47.

L8 22% Sulphur Super @ 500kg/ha 19 50% Sulphur Super @ 250kg/ha 50% Sulphur Super @ 500kg/ha 2 to ^ 21 Durasul 22 Durasul @ 125kg/ha @ 250kg/ha 23 Sulphate of Iron @ 125kg/ha 24 Sulphate of Iron @ 250kg/ha Zinc Sulphate @ 125kg/ha 26 Hydrated Lime @ 125kg/ha 27 Fertiliser Borate 28 Fertiliser Borate 29 Fertiliser Borate Fertiliser Borate @ @ 125kg/ha 50kg/ha 25kg/ha 12.5kg/ha Site 6 - Omarama(T) Treated -10/9/91 - seed applied 10/9/91 to Replicate 1 only Site 7 - Little Valley Treated - 26/9/91 - seed applied 26/9/91 to Replicate 1 only Site 9 - Nevis Treated - 7/10/91 - seed applied 7/10/91 to Replicate 2 only Treatment - 1 Fertiliser Borate - 12.5kg/ha 2 Fertiliser Borate - 25.0kg/ha 3 Fertiliser Borate - 50.0kg/ha 4 Fertiliser Borate - lOO.Okg/ha CONTROL Fertiliser Borate - 12.5kg/ha + 0-9-0 6 Fertiliser Borate - 25.0kg/ha + 0-9-0 7 Fertiliser Borate - 50.0kg/ha + 0-9-0 8 Fertiliser Borate - lOO.Okg/ha + 0-9-0 9 Fertiliser Borate - 12.5kg/ha + Fertiliser Borate - 25.0kg/ha + 11 Fertiliser Borate - 50.0kg/ha + 12 Fertiliser Borate - lOO.Okg/ha + CONTROL 13 Fertiliser Borate - 12.5kg/ha + 50% Sulphur Super 14 Fertiliser Borate - 25.0kg/ha + 50% Sulphur Super Fertiliser Borate - 50.0kg/ha + 50% Sulphur Super 16 Fertiliser Borate - lOO.Okg/ha + 50% Sulphur Super 17 Fertiliser Borate - 12.5kg/ha + Lime 18 Fertiliser Borate - 25.0kg/ha + Lime 19 Fertiliser Borate - 50.0kg/ha + Lime Fertiliser Borate - 100.0kg/ha + Lime *A11 fertiliser and lime sown at 250kg/ha 242541 Site 15 - Little Valley Site 16 - Omarama(T) Site 17 - Nevis Treatments - 1. 12.5kg/ha Borate 2. 25.0kg/ha Borate 3. 50.0kg/ha Borate 4. lOO.Okg/ha Borate Treated - 7/4/92 Treated - 7/4/92 Treated - 9/4/92 . 12.5kg/ha Borate + 200kg/ha 22% Sulphur Super 6. 25.0kg/ha Borate + 200kg/ha 22% Sulphur Super 7. 50.0kg/ha Borate + 200kg/ha 22% Sulphur Super 8. lOO.Okg/ha Borate + 200kg/ha 22% Sulphur Super Site 19 - Rees Valley Treated -18/5/92 Treatments - 1. lOOkg/ha Borate 2. lOOkg/ha Borate + 200kg/ha 22% Sulphur Super 3. 50kg/ha Borate 4. 50kg/ha Borate + 200kg/ha 22% Sulphur Super >. 25kg/ha Borate 24 ^ D 4 1 APPENDIX 2B Q.5ha Sites Site 3 - Little Valley Treated Site 8 - Little Valley Treated Treatments - 1. 12.5kg/ha Borate + 200kg/ha 33% Sulphur Super 2. 25.0kg/ha Borate + 200kg/ha 33% Sulphur Super 13/6/91 26/9/91 >rv .i Site 4 - Omarama(C) Site 5 - Omarama(W) Treatments - 1. Control = 200kg/ha of 22% S.S. plus 0 Borate 2. 200kg/ha of 22% S.S. plus 6.25kg Borate/ha 3. 200kg/ha of 22% S.S. plus 12.5kg Borate/ha 4. 200kg/ha of 22% S.S. plus 25kg Borate/ha . 200kg/ha of 22% S.S. plus 50kg Borate/ha Treated Treated 7/8/91 16/8/91 Site 20 - Omarama(C) Site 21 - Omarama(W) Treatments - 1. 200kg/ha 33% Sulphur Super 2. 200kg/ha 33% Sulphur Super 3. 200kg/ha 33% Sulphur Super 4. 200kg/ha 33% Sulphur Super Treated - 20/5/92 Treated - 21/5/92 + 12.5kg/ha Borate + 25.0kg/ha Borate + 50.0kg/ha Borate APPENDIX 2C 20ha Sites 24 Site 10 - Little Valley Treated - 26/3/92 Site 14 - Lindas Treated - 1/4/92 - seed applied 6/9/92 Treatments - 1. 25kg/ha Borate + 175kg/ha Molybdenised 22% Sulphur Super Site 12 - Millers Flat Treated - 30/3/92 Treatments - 1. 6.25kg/ha Borate + 175kg/ha Molybdenised 22% Sulphur Super 2. 25kg/ha Borate + 175kg/ha Molybdenised 22% Sulphur Super APPENDIX 2D 40ha Sites t 9 £ Site 11 - Little Valley Treated - 26/3/92 Treatments - 1. 6.25kg/ha Borate + 175kg/ha Molybdenised 22% Sulphur Super Site 13 - Beaumont Station Treated - 30/3/92 Site 18 - Nokamai Station Treated - 11/4/92 - seed applied 13/9/92 Treatments - 1. 25kg/ha Borate + 175kg/ha Molybdenised 22% Sulphur Super 242,

Claims (55)

WHAT WE CLAIM IS:

1. A method of controlling hieracium in pastureland which comprises applying a source of boron to said pastureland to increase the boron soil level available for pasture growth to a level of substantially 3ppm by weight or greater but below levels that are toxic to the pasture grasses.

2. A method as claimed in claim 1 wherein said boron is applied in the autumn and/or early winter.

3. A method as claimed in claim 1 or claim 2 wherein said boron is applied as a borate.

4. A method as claimed in any one of the preceding claims wherein said borate is applied at a rate which, when expressed as elemental boron, is greater than 2kg/ha.

5. A method as claimed in claim 4 wherein the application rate of the boron providing compound, when expressed with respect to elemental boron, is at a rate of about 3.75kg/ha.

6. A method as claimed in any one of the preceding claims wherein the boron providing compound is applied as sodium borate.

7. A method as claimed in any one of the preceding claims wherein said boron providing compound is applied to the pastureland in conjunction with at least one fertilising element selected from the group consisting of nitrogen, phosphorous, potassium, sulphur, magnesium, molybdenum and calcium in a fertiliser compound form.

8. A method as claimed in claim 7 wherein the boron providing compound and the at least one fertilising element is applied as a mixture/composition. f) E yf\ ^42 5

9. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 79% superphosphate, about 11.97% elemental sulphur and about 0.03% sodium molybdate.

10. A method as claimed in claim 9 wherein the application rate of the mixture/composition is about 250kg/ha.

11. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 20% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 35% elemental Sulphur and about 45% superphosphate.

12. A method as claimed in claim 11 wherein the application rate of the mixture/composition is about 125kg/ha.

13. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 40% elemental sulphur and about 50% superphosphate.

14. A method as claimed in claim 13 wherein the application rate of the mixture/composition is about 250kg/ha.

15. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 20% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 20% elemental sulphur and about 60% superphosphate.

16. A method as claimed in claim 15 wherein the application rate of the mixture/composition is about 125kg/ha.

17. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 22% elemental sulphur and about 68% superphosphate. ' .■ / v -56- ^28HARl?W ? c Z

18. A method as claimed in claim 17 wherein the application rate of the mixture/composition is about 250kg/ha.

19. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 90% superphosphate.

20. A method as claimed in claim 19 wherein the application rate of the mixture/composition is about 250kg/ha.

21. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 40% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 60% superphosphate.

22. A method as claimed in claim 21 wherein the application rate of the mixture/composition is about 250kg/ha.

23. A method as claimed in claim 20 wherein the application rate of the mixture/composition is about 125kg/ha.

24. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 5% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 12% elemental sulphur and about 83% superphosphate.

25. A method as claimed in claim 24 wherein the application rate of the mixture/composition is about 250kg/ha.

26. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% elemental sulphur and about 75% superphosphate.

27. A method as claimed in claim 26 wherein the application rate of the mixture/composition is about 25 Okg/ha. -57- 8 I'-AR ^

28. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 15% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% elemental sulphur and about 70% superphosphate.

29. A method as claimed in claim 28 wherein the application rate of the mixture/composition is about 125kg/ha.

30. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 80.6% magnesium superphosphate and about 0.4% sodium molybdate.

31. A method as claimed in claim 30 wherein the application rate of the mixture/composition is about 250kg/ha.

32. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 90% limestone.

33. A method as claimed in claim 32 wherein the application rate of the mixture/composition is about 300kg/ha.

34. A method as claimed in claim 8 wherein said mixture/composition is (by weight) about 5% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% potassium chloride, about 79.6% superphosphate and about 0.4% sodium molybdate.

35. A method as claimed in claim 34 wherein the application rate of the mixture/composition is about 500kg/ha.

36. A method as claimed in Claim 9 or any claim dependent thereon wherein said borate is a fertiliser borate substantially as hereinbefore described. -58- I

37. A composition comprising (by weight) 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 79% superphosphate, about 11.97% elemental sulphur and about 0.03% sodium molybdate, the borate compound(s) having been wet mixed with the fertiliser elements.

38. A composition comprising (by weight) about 20% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 35% elemental sulphur and about 45% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

39. A composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 40% elemental sulphur and about 50% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

40. A composition comprising (by weight) about 20% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 20% elemental sulphur and about 60% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

41. A composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 22% elemental sulphur and about 68% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

42. A composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, and about 90% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements. _ • \ o y » / '• -59- 12 8 MAR 5994 ?, t.

43. A composition comprising (by weight) about 40% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 60% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

44. A composition comprising (by weight) about 40% borate compound(s) when expressed as sodium tetraborate pentahydrate and about 60% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

45. A composition comprising (by weight) about 5% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 12% elemental sulphur and about 83% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

46. A composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% elemental sulphur and about 75% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

47. A composition comprising (by weight) about 15% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% elemental sulphur and about 70% superphosphate, the borate compound(s) having been wet mixed with the fertiliser elements.

48. A composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 80.6% magnesium superphosphate and about 0.4% sodium molybdate, the borate compound(s) having been wet mixed with the fertiliser elements. -60- 28n\5?>9»

49. A composition comprising (by weight) about 10% borate compound(s) when expressed as sodium tetraborate pentahydrate, and about 90% limestone, the borate compound(s) having been wet mixed with the fertiliser elements.

50. A composition comprising (by weight) about 5% borate compound(s) when expressed as sodium tetraborate pentahydrate, about 15% potassium chloride, about 79.6% superphosphate and about 0.4% sodium molybdate, the borate compound(s) having been wet mixed with the fertiliser elements.

51. A composition as claimed in any one of claims 37-50 when packaged with instructions to apply the same to a pasture infested or exposed to infestation by hieracium at a rate to increase the boron soil level available for pasture growth to a level of substantially 3ppm by weight or greater but below levels that are toxic to the pasture grasses or at a rate which provides the boron providing compound, when expressed as elemental boron, at an application rate of about 3.75kg/ha.

52. The use of a composition as claimed in any one of claims 37 to 51 in a method as claimed in any one of Claims 1-36.

53. The use as claimed in Claim 52 wherein the composition is applied to the pasture from an aircraft.

54. A composition as claimed in any one of Claims 37-51 which has been formulated by a wet mixing process.

55. A method of making a composition as claimed in any one of Claims 37-50 when performed substantially as hereinbefore described with or without reference to any example thereof. &GENTS FOR THE APP_L^ANTc