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, of size averaging around 26 - 37 kilobytes.)

• 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.
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• 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.
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• 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.
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• 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.
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• 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.
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• Molybdenum (Mo)
  Molybdenum, along with boron and chlorine, is an anion. As such, it’s 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.
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• 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.
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• 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.
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• 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).
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• 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.
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• 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).
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• 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.
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• 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.
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• 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.
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• 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".
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• 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).
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• 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 1970’s, 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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