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Articles Archive
Soiltech soil scientist David McKie writes articles on soil health issues, which are published in New Zealand rural newspapers.
Following is a list of articles published. Click on any name to download the complete article.
(All are in PDF format, and most are about 50 KB in size.)
- Climate, Greenhouse Gases and the Emissions Trading Scheme
We address two broad concerns about the ETS: firstly, a few practical considerations about the scheme and secondly, from a high level perspective, we question the approach to problem solving that undergirds the scheme.
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- Cadmium – What is Cadmium? (April 2013)
Cadmium (Cd) is a widespread, naturally occurring, element that is present in soils, rocks, waters, plants and animals.
The chemical symbol for cadmium is Cd. It occurs naturally with deposits of zinc and phosphorus but, unlike these
nutrients, it is not currently considered to be essential for life.
Download the full article »
- Has
Your Soil Had a Health Check?
Everyone recognises the importance of being healthy. When you eat healthy
food, in quantities appropriate for your age and body size, and combine
this with adequate sleep and exercise, it's a recipe for a healthy enjoyable
lifestyle. Conversely when you eat too much unhealthy food, and/or you
don't get enough sleep or exercise, there's a very good chance that your
health will suffer. In the same way, soils can also be healthy or unhealthy.
So before you order your fertiliser this spring, consider getting a soil health
check.
Download the full article »
- Soil Tests – Time for a rethink?
The term "soil test" means different things to different people. To some, it describes an
inexpensive tool which determines how much phosphorus fertiliser is required and whether
lime needs to be applied. At the other end of the spectrum are those who see a "soil test" as
a valuable resource; an excellent way to monitor soil function.
Download the full article »
- The Return of Natural Fertilisers
The name "fertiliser" can loosely be used as a label for any material that is applied to help boost the process of primary production. In our modern world, "fertiliser" typically equates to some kind of
manufactured inorganic material, generally containing a certain fixed percentage of nutrients eg
superphosphate (P – 9%, S – 11%, Ca – 20%). However, if it were possible to go back in time a 100
years, it is likely that "fertiliser" would mean something different, and most likely people would
think of a natural, organic product.
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- Understanding Soil Organic Matter
Soils comprise both inorganic and organic materials. "Soil Organic Matter" describes the various organic components present, which, in most NZ soils, typically comprise about 5-10% of a soil. Though minor compared to the amount of inorganic material present, organic matter is extremely important in the overall functioning of a soil. Organic matter can be partitioned as living biomass (living and intact organisms, plant and animal tissue, microorganisms); detritus (all non-living materials, dead
roots and other plant tissues and residues which can still be identified); and humus (other non-living materials which are no longer recognizable as plant tissue etc).
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- Is your soil healthy?
How someone answers this question indicates quite a lot about the way that person views the soil.
For some, "healthy" and "soil" are not words which would be used in the same sentence. For such
people, the soil is simply a medium to which fertilisers are added to improve plant growth. To them,
soil "health" means ensuring that there is an adequate supply of N,P, K & S. To others, the soil is
something which requires ongoing cultivation to enhance crop production.
Download the full article »
- It all begins in the soil
Whatever you do on the farm, it all begins with the soil. Soil is the foundation of every farming operation. Obviously then, to get the best from your farm, you need to get the best from your soil. "What is soil?" and "What does it do?" Can you give clear and concise answers to such questions? . . . I like to consider soil as three interrelated spheres: chemical, physical and biological.
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- Iodine (I)
Iodine is essential for animals but is not believed to be required by plants. Its main role is in the
production of hormones in the thyroid gland, with the latter also impacting a range of other
important animal functions i.e. metabolic rate, cell differentiation and the growth and development
of the foetus.
Download the full article »
- Cobalt (Co)
Cobalt is a trace element which is vitally essential for grazing animals, especially ruminants.
There is some evidence that Co has a beneficial effect on some plants, and it does play an essential role in nitrogen fixation by rhizobium bacteria in legume root nodules and in nitrogen fixation by blue-green algae.
Download the full article »
- Selenium (Se)
Selenium is a trace element which is essential for animals but not for plants. In animals, Se is
important for the immune system and also for the thyroid gland. About 30% of the agricultural land in New Zealand is affected by Se deficiency including most of the farmed land between Canterbury and Southland.
Download the full article »
- Molybdenum (Mo)
Molybdenum, along with boron and chlorine, is an anion. As such, its
availability in the soil is affected by absorption reactions such as those which also influence
the availability of other major anion nutrients such as phosphate, sulphate and nitrate.
Download the full article »
- Zinc (Zn)
Zn is an important element for stock health, more so in sheep than in cattle. Zinc also plays a
significant role in preventing and limiting facial eczema. Zn is also an important element for plant growth, being required in several enzymes, growth promoting hormones and in the formation of starch formation as well as in seed production and maturation.
Download the full article »
- Copper (Cu)
Though copper is essential for plants and animals, Cu deficiency is widespread in NZ and is found in sheep, cattle and deer. Cu deficiency is most frequently seen in organic soils (peats), podzols (West Coast forested areas and Northland gumlands), pumice soils, coastal sands, some recent soils derived from greywacke loess and limestone soils.
Download the full article »
- Iron (Fe)
Iron is taken up by plants at a much higher rate than is the case with other trace elements. Though
major nutrients like phosphorus and sulphur are often analysed in soil tests and the trace element
iron is ignored, it is important to appreciate that iron is essential for plant (many enzymes,
chlorophyll formation, nitrogen fixation etc) and animal life (blood, many enzymes).
Download the full article »
- Manganese (Mn)
Mn is a necessary element for a range of plant, animal and microbiological functions i.e.
photosynthesis in plants, nitrogen metabolism and assimilation in plants and microorganisms, and
the development and function of the reproductive system, maintaining healthy nervous system,
structural protein synthesis, energy production, health of joints and proper bone formation in
animals.
Download the full article »
- Boron (B)
Boron is essential for plants, playing a major role in the carbohydrate metabolism including the
production and storage of sugars. It is also believed to be important in protein production and
general cellular activities (division, growth, respiration, maturation and differentiation e.g. the
formation of fruit cells).
Download the full article »
- Ignore Trace Elements At Your Peril
Because the amounts of trace elements required by both plants and animals are tiny compared with their requirements for nitrogen, phosphorus, sulphur, magnesium, potassium etc, it can be tempting to
focus more on maintaining the supply of these later macro-nutrients than the seemingly
insignificant trace elements.
Download the full article »
- Promising Fertiliser Trial Results, Part B
Between March 2005 and March 2007, Soiltech supervised a trial comparing Mainland Minerals (MM)
fertilisers with conventional superphosphate. This is the second part of the report on that study.
Download the full article »
- Promising Fertiliser Trial Results
Between March 2005 and March 2007, Soiltech supervised a trial comparing Mainland Minerals (MM)
fertilisers with conventional superphosphate. The trial objective was to measure and
compare the dry matter responses of different MM fertilisers and Superphosphate in a dry climate.
Download the full article »
- Stock Health Begins in the Soil
Every year, millions of dollars are spent on veterinary medicines and related costs trying to
overcome the problem of unhealthy stock. In fact, for most farmers, veterinary costs have become a necessary and accepted budget item, even though they significantly erode the "bottom line".
Download the full article »
- Benefits of Limeflo Fertiliser Demonstrated (Part B)
Last month I reported on a trial to investigate what benefits, if any, would accrue from applying Limeflo. Unfortunately, the article was too long and some of the content was edited out. In
this article, I present the balance of the information.
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- Benefits of Limeflo Fertiliser Demonstrated
Reports on another trial to investigate what benefits, if any, would accrue from applying finely ground calcium carbonate or Limeflo. Many farmers think there are only two soil criteria that really matter, pH (which
measures acidity) and Olsen P (which measures plant available phosphorus).
Download the full article »
- Fertiliser Trial Demonstrates Excellent Stock Performance
For the past 3 seasons, Soiltech has overseen a trial for Mainland Minerals to evaluate any stock performance differences which might result from using Mainland Minerals fertiliser system rather than conventional granular fertiliser. The trial arose largely from the dissatisfaction of the farmer with the stock performance he was obtaining after years of using granular fertiliser.
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- Probitas Court Case Raises Questions
The recent Tauranga District Court decision against the Probitas fertiliser company raises questions, whichever side of the fertiliser debate one is on. If you see plant growth and productivity as involving more than soil chemistry, you are likely to view the decision with some dismay. Download the full article »
- Balancing Potassium Requirements
It is worth the effort to ensure the legumes are well supplied with adequate nutrients because they reward you by providing significant quantities of �free� fixed nitrogen to drive grass growth. Download the full article »
- Is Your Soil Healthy?
Soil is the foundation of every farming activity. Whatever your operation, it all begins with the soil! Therefore, if you want to get the best from your farm, you need to get the best from your soil. This will only happen if your soil is healthy! Download the full article »
- Challenging the Fertiliser Paradigm
The current "fertiliser paradigm" summarises the prevailing mindset as to the reasons fertiliser is applied (including content and quantity) and its impact on the soil. Download the full article »
- Improving Hill Country Production
Rather than trying to "squeeze the last drop" from the flats, what if we started thinking differently and looked for more return from the hill country? Download the full article »
- Need More Fertiliser P?
Grazing animals obtain the P they require from plants, which in turn extract it from the soil in which they grow. Humans derive the P they need by eating primary produce. Download the full article »
- Soil Spheres: The Key to Better Productivity
If you want to get the best from your farm, you need to get the best from your soil. The way to do this is by improving your understanding of this valuable resource which lies hidden, and largely forgotten, beneath your feet. Download the full article »
- Re-assessing Agriculture's Objective
As primary producers, it is easy to get so caught up in running the business that some of the big
questions, like "Why am I doing what I do?" get overlooked. Download the full article »
- Is Urea Agriculture's "Silver Bullet"?
The application of nitrogen in the form of urea has become the trendy way to farm in recent years. This approach reduces the complex holistic system we call "farming" to little more than a simple mathematical calculation. Download the full article »
- Suffering From P Fixation?
Many farmers are obsessed with the Olsen P levels of their soil. Listening to them, you get the
impression that maintaining or elevating Olsen P is all one needs to know about the soil! Yet P
is just one of many essential nutrients required by the growing plant! Download the full article »
- What Happens to Superphosphate P in the Soil?
Superphosphate (Super) is still the dominant phosphorus (P) fertiliser used in NZ. Despite this,
Super users often have little idea of what happens to the P supplied in this fertiliser when it is added to the soil. Download the full article »
- Trace-El Boosts Silage/Baleage Mineral Levels
The benefits of mineral supplementation are well known throughout New Zealand. Trace element
limitations to farm performance go well beyond the classic cases. Download the full article »
- Time For More P Fertiliser?
Because NZ soils are generally quite low in phosphorus (P), fertiliser P inputs have been
a major factor in NZ agriculture for many years. Download the full article »
- Soil Organic Matter: An Overlooked Resource
Soil is the foundation of every farming enterprise. Surprisingly, many farmers have only a
rudimentary understanding of this important farming asset. Download the full article »
- Soil and Cultivation
Soil is the foundation of every farming operation. Yet if someone asked: "What is soil?" or "What
does it do?" it might be a struggle to give a meaningful answer. Download the full article »
- Calcium Plays a Vital Role in the Hill Country
To claim that "carbonate, not calcium is needed on hills" as your headline suggests is
at best misleading, and at worst, mischievous and dishonest. Download the full article »
- Resin P Test
Over the years much research has focussed on the development of suitable soil tests
to measure levels of soil phosphorus (P). In the mid 1970s, the Olsen P test
demonstrated itself to be the best test available. Download the full article »
- Quality Supplementary Feed Starts in the Soil
The value of supplementary feed depends on both the quantity and quality of stored feed
harvested. Download the full article »
- Phosphorus "Gold Mine" in Your Soil
Most New Zealand farmers are sitting on a goldmine! Not the precious mineral sought by
miners long ago but a stockpile of invisible phosphorus hidden in the soil. Download the full article »
- pH and Nutrient Availability
The pH, or acidity, of the soil refers to the concentration of hydrogen ions present in soil
solution. The term "pH" is derived from a mathematical logarithmic correlation. Download the full article »
- Mainland Minerals Improves Hill Country Productivity
It is a well attested fact that each of us is often blind to the most obvious things. In many situations we become so used to operating in a certain way that, if we continue to do that for a long enough period of time, we become closed to other options. Download the full article »
- Misled By Olsen P?
Many farmers have an obsession with the Olsen P levels of their soil. For them, maintaining or
elevating Olsen P is just about the only reason for soil testing! Yet P is just one of many
nutrients required by the growing plant! Download the full article »
- Is Pasture Renovation Necessary?
"Nothing lasts forever" or so the old saying goes. This is as true of pasture as it is of
fertiliser or anything else. The time will eventually come when either the grasses or
the legumes or both are no longer performing at an optimal level. Download the full article »
- OLSEN P: The Best Test for Soil phosphorus?
Phosphorus (P) is of critical importance in NZ agriculture, mainly because it exists at plant
available levels in most soils which are too low for optimal production. Download the full article »
- Ignore Soil Organic Matter at your Peril
Although the soil is the foundation of every farming enterprise, many farmers have only a
basic understanding of this important farming asset. Download the full article »
- How to Maintain 250SU/ha!
"Stocking rate" is a term which indicates how many animals a farm can comfortably
run. As such it is a good pointer to its fertility and economic potential. Equally
important in this regard and usually overlooked, is the stocking rate of the invisible
organisms that live below the surface of the ground. Download the full article »
- FPF Improves Phosphorus Usage
Pasture-based farming in NZ has a long tradition of relatively heavy application of phosphate fertilizers, generally based on Olsen P test readings. Download the full article »
- Fine Lime Boosts Soil Biology and Farm Productivity
In the mindset of many farmers, lime is applied for 2 main reasons: either to raise soil pH in
acid soils or to maintain soil pH at desirable levels. Lime also has many other more startling but
less well known benefits. Download the full article »
- Fertiliser - Is It Value For Money?
We live in a "market driven economy". This means that retailers (fertiliser
companies) are constantly clamouring for the consumers (farmers) attention, hoping
you buy their product. How do you decide which to buy? Are they all value for
money? Download the full article »
- Fertiliser – A Cost or a Benefit?
For any enterprise to be successful, the "money spent" must be offset by the "money received".
This is basic economics! If this is not the case, then the business is heading for rocky times! Download the full article »
- Comprehensive Soil Test Benefits
Topsoil may well be the farmer's greatest asset. The fertility of the top few
centimetres of the soil largely determines the farms productivity. Download the full article »
- Big Benefits From Fine Particle Fertilisers
Fine particle fertilisers offer a number of significant benefits. Before discussing some of these, let's be sure we understand what we're talking about. Download the full article »
- Comparison Between Bulk Lime and Limeflour
Bulk Lime (AgLime) is applied primarily to increase the soil pH over the medium to long
term in soils that are too acidic for optimum agricultural production. In essence there
are three main benefits of this exercise. Download the full article »
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