Much of the credit for the improvement in plant quality and palatability resulting from their use is given to the wide range of minor or trace minerals all fish and seaweed contain.

Often these elements are only present in parts per million and when diluted and applied to pasture the effectiveness of such small amounts is often queried.

Having farmed within five kilometres of the coast as well as far inland as it is possible we have our own views on the effect of small quantities of salt and accompanying minerals carried by rain and wind coming from the sea can have.

In our experience animals reared on pasture close to the coast require are generally healthier.  Our young dairy replacements required less animal health remedies particularly worm drenches. The requirement of lactating cows for sodium was almost nil close to the coast.  Inland, for optimum health and performance, sodium supplementation was a constant requirement.

Two years ago a highly respected stockman farming inland hills introduced some of his young beef animals to fresh seawater.  Fresh water was always available so animals were never forced to drink seawater, however seawater was drunk in surprisingly large quantities.

Although not a scientific trial this farmer became increasingly certain that based on his observation and the results from regular weighing, the animals that had access to salt water grew more rapidly.

Dolomite mined near Collingwood was originally a seabed deposit and therefore contains a range of trace minerals.  Typically Dolomite contains Boron 5ppm (parts per million),

Cobalt 2ppm, Copper 1ppm, Manganese 173ppm, Molybdenum 3ppm, and Zinc 10ppm.

With the typically recommended application rate of 200 – 250kg/ha the rates of trace minerals input appears inconsequential however farmers and growers that regularly apply dolomite often claim general health benefits that cannot be attributed entirely to the calcium content of 24%, and magnesium content of 11.5%, both in the carbonate form.

Being a proven soil conditioner that improves soil tilth some of the improvement will be due to improved nutrient availability and the more rapid exchange of gasses to and from soil and atmosphere.

It is thought that even very small quantities of trace minerals may increase growth-promoting substances in the soil able to be utilised by plants.  With all growing situations there are many factors that influence at any given time however there are frequent reports citing a general improvement in plant and animal health as a result of regular dolomite usage when applied at the rate required to meet soil magnesium requirements.

Some years ago a small dairy company found that dolomite markedly improved the palatability of pasture on paddocks to which effluent was regularly applied.  After trying a number of different remedies pasture that cows were reluctant to graze became acceptable after a single dolomite application.

For more information call 0800 436 566 (0800 4 dolomite)

The questions were, “what is dolomite” and “why don’t we still use it?”  The answers were that dolomite was the most effective magnesium fertiliser available and when the cost of the freight was no longer subsidised it became too expensive.

That conversation took place in 1979.  Dolomite remains the most effective magnesium fertiliser today and there is a commitment from the mine owners and those involved in transport, storage, marketing and selling, to mine it and transport to property as cost effectively as possible.

Too dear?   The cost is measured against the benefits and it will differ for each.

Dolomite is similar to lime in that both contain calcium in the carbonate form.  The analysis is 59% calcium carbonate and 39% magnesium carbonate, which convert to 24% calcium and 11.5% magnesium.  Dolomite is only applied where there is a need for magnesium.

Being in the carbonate form provides much of the unique benefit.  The rate of release of finely ground carbonate is in sync with demand.  Whilst soil temperatures are low release is relatively slow increasing with temperature and peaking in spring when demand is highest.

The rate of application is usually around 220kg/ha providing 25kg Mg/ha.  Even in the most demanding situation this is sufficient to minimise calcium/magnesium related metabolic situations in spring.  Should it be applied a little heavier the effect will simply last a little longer.

A 28 tonne truck and trailer load provides sufficient magnesium for 127ha.  If the area to which it is spread is less, a smaller quantity may be purchased from a local provider.

The price per tonne increases with distance from the mine at Golden Bay.  Dolomite can be delivered to Central Canterbury properties in truck and trailer load lots for $151.20+GST/tonne.  The price per hectare at a spreading rate of 220kg/ha is therefore $33.26+GST not including the cost of spreading.

For that price all animals well fed on dolomite dressed pasture are unlikely to suffer a severe calcium/magnesium imbalance.  Our experience is that calcium/magnesium related metabolic disorders are few and when treated recovery is usually rapid.

The following, by John Ruskin is worth keeping in mind -

“It is unwise to pay too much, but it is worse to pay too little.  When you pay too much you lose a little money – that is all.  When you pay too little, you sometimes lose everything because the thing you bought was incapable of doing the thing it was bought to do.  The common law of business balance prohibits paying a little and getting a lot – it cannot be done.”

During the 1960s and 70s when there appeared a greater appreciation of the importance of the farming to the financial well-being of the nation the cost of the cartage component of dolomite to farm was subsidised.

The rationale was that the benefits gained from improved farm performance resulting from its use were greater than the cost of the cartage and a greater tonnage of dolomite was sold for pastoral use than has been the case in recent years.

The improvement in overall animal health as a result of an annual dolomite application has never been queried.  Although a marble and therefore very hard the fineness of grinding ensures rapid release of both magnesium and calcium.

On properties where calcium/magnesium related problems are severe marked improvements in animals have been observed as soon as a fortnight after application.

An often-used objection for the use of dolomite is the price.  This is based on the premise that it doesn’t matter in what form magnesium is applied to the soil.

Healthy soil is a living breathing organism teeming with life and what is applied to it and the form in which it is applied has a significant effect on soil processes which in turn has a similar effect on the mineral status and health of plants, animals, and ultimately the final consumers, us.

Dolomite is a natural seabed deposit now above ground but still containing a wide range of minor minerals.  It is highly regarded as a human magnesium/calcium health supplement with no difference between that sold in capsules and what is delivered to farm in 28 tonne truck and trailer loads.

The theory of applying product that provides nutrient at the lowest cost ignores the importance of outcome and no fertiliser product is applied without the expectation of some benefit occurring.

Laboratory analysis and performance modelling may be useful however farmer observation and experience over many years is perhaps of greater value and farmers that are dolomite devotees have become so based on proven and consistent performance.

Soil life is a vital aspect of successful pastoral farming.  As Dr Graham Sparling stated in his 2004 Norman Taylor Memorial Lecture “soil is only soil if it has biological activity, otherwise it’s dead like moon dust…”

For maximum biological activity soils need to be well structured so that air can enter rapidly and gases, predominantly carbon dioxide, leave.

Dolomite is a proven soil conditioner unique in its ability to provide an excellent balance of both calcium and magnesium with regular measuring indicating higher energy levels in pasture and crops to which dolomite has been applied.

We had the privilege, prior to Christmas, of visiting a Collingwood grazing property with stock as good as it is possible to see anywhere in the country.

Without exception all animals were big framed, deep bodied, glossy coated, clean, and not excessively fat. Typical of stock fully fed on pasture of exceptional quality, they were inquisitive and playful but docile.

Rapid animal growth rates without the need for high energy supplement and regular use of animal health remedies can be achieved by ensuring soil health is robust at all times. The annual application of dolomite applied at the rate required for optimum plant magnesium levels is an excellent first step.

At this time of the year soil moisture or the lack of it is foremost in farmers and growers minds. With pasture roots able to penetrate and access moisture to a depth of 0.8m (30 inches), it takes a prolonged dry spell to deny plants sufficient moisture for measurable growth.

Often the most noticeable change pasture in January and February is the change in colour. Brown does not mean growth has stopped. In spring pasture dry matter is often as low as 18% dry matter compared with recently cut pasture averaging 24% –27% dry matter. The eye needs to be recalibrated to ensure that the quantity of short brownish summer pasture is not underestimated.

Brown does not necessarily mean lack of quality either. High quality hay can be an excellent source of feed while summer pasture of the same colour and similar composition is often regarded as second rate. Careful observation of animals grazing short brownish pasture is the best means of ascertaining both quality and quantity.

We have at present hinds grazing apparently dry brown pasture that are at least maintaining weight as well as rearing exceptional fawns. A close examination of the pasture reveals green leaf close to the soil surface, and because there is plentiful feed due to excellent December growth, and the troughs are clean, all animals will continue to perform well over the next month even with little rain.

On physically well-structured soils moisture is able to move both downwards and perhaps a little surprisingly upwards. The rate of moisture movement upwards may not be rapid but is often sufficient for plant survival ensuring significant response to even small quantities of summer rain.

Some years ago a farmer client related the story of the farm of two halves. One half was managed by the owner the other by a sharemilker. Stocking rate, contour, and pasture management was little different as was production throughout spring and summer.

With the arrival of summer rain one half of the property visibly changed colour more rapidly than the other with a corresponding lift in pasture growth. After careful thought the owner attributed the more rapid response to the dolomite that had been applied in winter to that half of the property.
The rate of application on intensive dairy properties is usually 220 – 250kg of dolomite (25kg – 28kg Mg) per hectare. On grazing properties it may be as little as half or may be applied at the dairy farm rate once every second year.

In the interim some have applied other magnesium ‘fertiliser’ the decision being made on the basis of price. The results have disappointed and the decision to return to dolomite applications is unlikely to be changed.

These farmers and growers understand that price is one aspect however the benefits received from the application is the true measure of value.

Value can only be ascertained by an appreciation of what dolomite delivers. Experience is required to fully appreciate the improvement in general animal health, the reduction in calcium/magnesium related metabolic disorders, and the ability to provide more highly nourishing clover growth over summer.

With major nutrient fertiliser at current prices an increase in the effectiveness and efficiency of applied nutrient may reduce the amount required, which is best monitored with regular soil and leaf tests.

The improvement in physical soil structures from a single dolomite application is often quite obvious. The improvement in the water absorbing ability of dry sandy soils is often remarked on. Home gardeners using dolomite in gardens exposed to the north appreciate this benefit.

Dolomite also has a unique ability to condition or soften soil compacted by animal feet particularly during periods of excessive moisture encouraging plant roots to develop deeper in to the soil.

Deeper root penetration allows the plant access to increased quantities of both nutrient and moisture. Mycorrhizae, a term meaning “fungus root”, play an important role in the ability of plants to take up phosphorus and other nutrients relatively immobile and present in low concentrations in the soil solution.

These fungi invade the plant root and a relationship develops whereby both the plant and fungi benefit. Moisture uptake may also be improved by mycorrhizae, which can extend the plant roots absorptive surface by up to ten times compared to an uninfected plant. There may also be increased protection from soil borne diseases and parasitic nematodes resulting in healthier stronger above ground growth

In return these beneficial fungi derive energy in the form of sugar direct from the plant reducing their need to compete with other soil organisms. Phosphorus is an essential element in the formation of sugars and a plentiful supply of available phosphorus helps ensure maximum sugar formation in the plant leaf providing the necessary energy for further phosphorus uptake by the fungi.

It is probable that all our pastoral soils contain mycorrhizae. Plants in soils to which dolomite is applied are able to develop roots to a significantly greater depth and in conjunction with mycorrhizae their ability to extract nutrient and moisture resulting in higher levels of total growth is enhanced.

Dolomite sales have however bucked the trend, and even into November demand is steady, a tribute to its effectiveness and value.

Value in this case can be defined as the dollars saved and extra generated as a result of its use less the cost. This may be difficult to calculate with great accuracy however those that apply dolomite regularly often become devotees.

In pastoral farming dolomite is applied for its magnesium content. Soils vary in the amount of magnesium contained naturally in the root zone accessed by ryes and clovers. Soils high in organic matter often contain the most due to the large nutrient storage capacity compared to coarser textured soils.

The loss of magnesium from intensive dairy properties, as far back as the 1960’s, was calculated at 15kg/ha/year.

With markedly higher stocking rates, higher inputs of potassium, and regular inputs of nitrogenous fertiliser losses will now be considerably higher though probably not exceeding 25kg/ha/year. Irrigation may well increase leaching losses.

Soil and leaf testing will help quantify the need for magnesium however those that have neglected magnesium inputs to the point of low availability understand both the trauma involved with acute magnesium deficiencies in stock and the amount of money that can be lost with just the loss of one high producing animal, often its progeny of that season, and the loss of production.

The prevention of magnesium deficiencies is often as simple as applying 20 – 25kgMg/ha/year in the form of dolomite. With dolomite typically containing 11.5% magnesium the recommended application rate is 220kg/ha.

On the light pumice based soils of the North Island’s Central Plateau where dolomite is applied regularly to many hectares under intensive dairy 220kg/ha is sufficient to prevent all simple magnesium related metabolic disorders provided animals are fully fed on high quality pasture.

Where potassium inputs are withheld until November, animals are fully fed and rumens are functioning well, often the only extra magnesium needed is during prolonged spells of both cold and wet weather.

Dolomite also contains 24% calcium. Once lactating, the demand for calcium increases and dolomite provides a ready source, an attribute unique to dolomite.

One of the yet to be fully understood reasons for the marked improvement in animal health as a result of regular dolomite applications may be that magnesium is also a carrier for phosphorus. Phosphorus is an important growth element also essential for the formation of sugars in plants.

In spring the demand for energy by animals increases. Higher energy pasture is lower in crude protein and more energy is available for essential body functions including good rumen function ensuring more of the ingested magnesium is utilised.

Dolomite can be applied at any time of the year with the effect lasting a full twelve months.

Short frost damaged grass abundant on properties monitored this spring is highly palatable and contains much of what cows need soon after calving. Fibre levels are relatively high, dry matter is low, and stock are easily satisfied on what appears to be a meagre amount.

More rapidly grown grass has recently been measured at 14% – 20% dry matter with brix levels of 9.5. Slower growing grass was measured at 20 –28% dry matter with brix levels of 11 – 13.5.

We are still learning the relevance of brix to animal performance however properties monitored where stock are grazing high brix pasture this spring have low somatic cell counts, very few cases of clinical mastitis, and a low incidence of calcium/magnesium related metabolic disorders.

Pasture energy levels are directly related to sunshine hours and the ability of the plant to photosynthesise. Photosynthesis is the process by which plants utilise sunshine to build energy, which is then fed to animals to produce food.

Soil temperatures largely govern the increase in the rate of growth in spring, with the greatest influence being direct sunshine hours. Springs following dry frosty winters usually receive more direct sunlight.

It may therefore be that the apparent low pasture covers worrying many this spring contain as much energy as greener, taller, lower dry matter pastures typical of August, and energy is the key to production.

Regular monitoring of brix levels on properties using Golden Bay Dolomite based nutrient programmes over the last two years has indicated that as brix levels in pasture increase so too does animal weight and total production. There also appears to be a corresponding decrease in somatic cell counts and the incidence of clinical mastitis.

The ability to increase plant energy levels regardless of how they are measured is the ability to provide an environment that suits the plants we wish to grow and the provision of all nutrients as required by the plant.

Friable soils with excellent crumb structure provide the best medium for pasture plants. Excellent structure is achieved by ensuring biological activity is maximised and this is achieved by providing regular inputs of calcium as calcium availability drives beneficial soil biology. Dolomite contains both magnesium and calcium in the proportion beneficial to plant and stock health.

Well-drained friable soils are also able to hold more moisture. The root zone on monitored properties is often as deep as 0.8m. This ensures that growth throughout the drier months of January, February, and March is maximised. With strong pasture and animal production during this time a successful outcome to the season is largely guaranteed.

Golden Bay Dolomite often provides both an almost immediate response and a season long affect.
When it comes to a magnesium/calcium fertiliser GB Dolomite is almost the perfect fit. Although technically a marble therefore extremely hard, when ground to the typical particle size of product supplied for pasture the response can be very rapid.

The initial breakdown of very fine particles takes place mostly as a result of the acidic conditions on the soil surface, releasing both magnesium and calcium. Larger particles incorporated into the soil as result of treading and earthworm activity will breakdown more slowly providing a steady supply over twelve months.

Dolomite encourages earthworm activity. The most common earthworm is the Apporectodea caliginosa. Beneficial earthworms in pasture are almost universally introduced worms that arrived in the ballast of ships or with trees that began arriving here over one hundred years ago with native bush dwelling earthworms not suited to pastoral conditions.

Dolomite itself has a soil conditioning or flocculating effect. Flocculation is the process of soil particles joining together in clumps thereby increasing pore space. Increased pore space speeds moisture movement through the soil.

In conjunction with strong earthworm activity moisture infiltration rates increase. One study showed the infiltration rate increasing from 12.5 mm to 25 mm/hr as result of increased earthworm numbers and activity. The same study also showed moisture holding capacity increased 17%.

This means earlier spring growth as a result of better drainage in winter as well as higher pasture production over summer.

With improved physical soil structures nutrient is cycled more rapidly resulting in more total growth throughout the season. Only a very small percentage of nutrients stored in the soil are available to plants at any given time so speed of cycling is important.

With greater nutrient availability pasture energy levels can also be expected to be higher, resulting in better animal gut function with the resultant dung more readily incorporated back into the soil.

Dolomite does not replace required inputs of phosphorus and sulphur but does help address the ongoing requirements of both magnesium and calcium.

Ideally Base Saturation Calcium levels should be close to 65% with a marked increase in phosphorus availability between pH 6.0 and 6.5. Magnesium Base Saturation levels of 10% ensures maximum pasture growth.

At this level there is also likely to be sufficient plant available magnesium for only small quantities of extra magnesium required to be fed at strategic times and dolomite either drenched, dusted, or incorporated into a lick, is effective.

There appears to be an ongoing balancing act taking place with weather patterns and their consequences. Will what has been a severely cold winter for most areas turn into an outstanding spring? In some areas early season bulbs have appeared a little earlier than normal while in other areas they are a little later than usual.

There are however some things we can be reasonably sure of. Dry frosty winters normally precede memorable springs. Memorable for strong sunlight, contented healthy stock, and rampant pasture growth, when it arrives.

Soil temperatures dictate when strong spring pasture growth occurs and although frosts bring soil temperatures down, the sunlight that follows dries the soil. Dry soils warm more rapidly in spring with direct sunlight hours having the greatest influence.

An annual application of Golden Bay dolomite provides a range of benefits for pastoral farmers and growers dependant on soils for their livelihood.

Dolomite contains typically contains 11.5% magnesium and 24% calcium and is applied annually wherever there is a requirement for magnesium, normally at 250kg/ha, which applies 28 – 29kg of magnesium.

The long-term efficiency of dolomite is in large part due to it being a natural rock. Finely ground it is rapidly assimilated into the soil organic matter and the release rate of calcium and magnesium fits closely with plant demand. Little is lost via leaching or run-off.

Originally laid down on the ocean floor millions of years ago, dolomite contains a wide range of trace elements essential for plant and animal health. These traces although small contribute to the outstanding health of stock grazing or plants growing on land to which dolomite is regularly applied.

Regular applications of dolomite stimulate beneficial earthworm activity as a result of the direct soil conditioning effect and the supply of calcium.

As early as 1945 observers in New Zealand recognised the beneficial effect of earthworms and in the early 1950s trial work over a 20 month period showed increased pasture yields of 28% – 110% as a result of beneficial earthworm activity.

Reports from that time stated that where earthworms are active dung and plant residues are incorporated into the topsoil enriching it in organic material and available plant nutrients. Plant growth substances are secreted and passed into the soil. Physical structures are improved with better infiltration of rain, improved moisture holding capacity and root development.

With the likelihood of a dry spell sometime during summer the benefits of improving the moisture holding capacity of the soil are self-evident.

It may be low tech by some standards however its effectiveness is unequalled. The application of dolomite at any time during the year is guaranteed to provide substantial benefits resulting from improved soil and animal health.

Regardless of the price of other magnesium fertilisers, dolomite has always provided outstanding value, which is the difference between what is paid and the monetary return.

Dolomite now has a marked price advantage when compared to magnesium oxide, in some areas. The present price of magnesium oxide supplies magnesium at approx. $1.30/kg of magnesium.
Dolomite contains approx. 115kg magnesium per tonne (11.5%) and is available in bulk ex Richmond at $90.00+GST/tonne, which equates to 78cents/kg of magnesium.

When the cost of cartage is included for truck and trailer loads delivered to Central Canterbury properties the price is $1.35/kg magnesium, and to South Canterbury properties $1.43/kg magnesium.

The effectiveness of dolomite relates to its unique composition, typically 11.5% magnesium and 24% calcium.

Metabolic disorders due to a lack of magnesium (hypomagnesaemia) often also involve calcium, if not at the time almost certainly soon after. Body reserves of magnesium are too small to meet the increased demand just prior to and after calving so sufficient needs to be ingested on a daily basis.

The ability of a single application of dolomite to markedly reduce the severity of these problems as well as help eliminate all but the worst cases is due in large part to the balance of magnesium and calcium.

Leaf analysis over years of monitoring indicates that a single application of dolomite at approx 250kg/ha (28kg/Mg) will lift magnesium leaf levels to between 0.22% and 0.25%. Animals well fed on pasture containing these levels are likely to have their magnesium intake requirements met.

To maximise milk production spring pasture needs to have calcium levels of 0.60% or higher. Pasture to which dolomite has been applied nearly always surpasses this level.
The quality of pasture is largely dictated by soil quality with well-aerated and flocculated soils usually having higher mineral content and energy levels. Dolomite being a natural deposit contains a wide range of trace elements further enhancing its performance.

Dolomite assists with physical soil structures, increasing humus content and improving tilth. Well-aerated soils drain more rapidly after heavy rain and consequently warm a little more quickly providing earlier spring growth.

Dolomite is finely ground ensuring rapid response. An improvement in animal performance can often be noticed within a fortnight of application allowing dolomite to be applied at any time with positive results.