GrowMore Virtual Agronomist is built to support faster, clearer fertiliser decisions. Giving Farmers full visibility of what the Market prices are. Meaning an Agronomy Plan can be constructed the minute soil test results are known. Reducing delays. Improving outcomes. Saving money.
Because the Science behind it is already well understood. And the observations made by the Science can be well described using Math. And computer code is very good at Math, perfect even.
That’s not to say the app can overcome poor soil sampling protocols - it can’t. Garbage in = garbage out. But the fundamentals of plant growth — what nutrients are required and how they affect production — were established decades ago with few real breakthroughs in recent years that fundamentally change how pasture responds to nutrients. After all Farmers have long understood that, if you don’t put back in what you take out the earth quickly defeats you - whether those nutrients are refined fertilisers or organically sourced makes scant difference.
New Zealand, in particular, has a strong foundation in soil science with local research playing a major role in calibrating how much of each nutrient is needed to achieve near-optimal pasture production under our conditions. That includes understanding how different soil types respond, and how nutrients like sulphur behave across those soils.
At the same time, the limits are well known, Nitrogen fertiliser has become a powerful tool for filling short-term feed deficits, and it has driven significant gains in production. But it comes with environmental constraints and is not a complete solution on its own.
Most importantly New Zealand soils are geologically young, generally high in organic matter, naturally acidic, and commonly low in phosphorus and sulphur. Under modern farming systems, other nutrients can also becoming limiting. Potassium deficiency is not unusual, particularly under intensive dairying, and is increasingly being seen on sedimentary soils under drystock systems. In some cases, trace elements such as molybdenum are also being depleted over time.
None of this is new science. What has changed is the ability to apply that science consistently and quickly without the friction that traditionally limited its use — enabled by the advent of mobile-based decision support systems.
The mobile app puts this knowledge within your control and allows you to apply it to your specific farm, and present the result in a clear and structured way — including how different supplier options meet those requirements.
It is a tool for applying known science more efficiently, not reinventing it.
The app also provides an alternative way of interpreting soil test results using the Base Cation Saturation Ratio (BCSR) approach.
This method focuses on the balance between the major cation nutrients — calcium, magnesium, potassium and sodium — relative to the soils total exchange capacity. It is commonly referenced in some systems, particularly in turf and certain international agronomy circles, and is included here as an additional lens for understanding soil fertility rather than a replacement for conventional methods.
It should be clearly understood that, within this app, the BCSR approach applies only to the interpretation of cation nutrients and has no bearing on the calculation of phosphorus or sulphur requirements. In practice, its usefulness depends on the accuracy of soil test data and the conversion of laboratory results into consistent units such as kg/ha, alongside the target base saturation percentages often cited for these elements. It should also be understood that these conversions were based on the agronomy of crops with the soils they were grown in being frequently cultivated to a depth that became known as the "Acre Furrow Slice", the depth which a plow turned soils over with soils all being regarded as having similar bulk densities.
The approach also tends to favour maintaining trace elements at levels more consistent with “adequacy” rather than operating close to marginal or deficient levels.
The intent is to give farmers visibility across both approaches, allowing them to compare interpretations and make informed decisions within the context of their own system.
Beyond SLAN and BCSR, a number of alternative soil testing and interpretation philosophies exist. The most widely referenced of these is the Reams approach, along with a range of localised variants promoted in different regions. These systems often place emphasis on broader interpretations of soil condition, sometimes incorporating concepts such as “total” nutrient levels, soil energy, or biological indicators as primary drivers of fertility decisions.
GrowMore is not closed to the possibility of future advances in soil science. New ideas should always be considered where they are supported by sound methodology — that is, repeatable observation, measurement, and empirical validation. However, the standard applied is the same as any other area of applied science: claims must be testable, consistent, and demonstrably linked to production outcomes.
It is important to distinguish between what is measurable and relevant, and what is not. For example, reliance on “total” elemental tests does not reflect plant-available nutrients and can be misleading in a fertiliser decision context. Measuring total phosphorus in a soil is not materially useful when plants respond to the fraction that is available. In effect, this is closer to a mining assay than a soil test.
Similarly, broader claims around soils being “electric” or governed primarily by loosely defined biological or carbon-based frameworks should be treated with caution. While soil chemistry, physics, and biology are all important, they must ultimately be grounded in measurable effects on plant growth and farm performance. Concepts such as building soil carbon or promoting biological activity may have merit in certain contexts, but they are not, in themselves, prerequisites for running a productive and profitable farming system.
In some cases, the practical application of these approaches extends to the sale of materials such as sands, clays, or rock dusts, often attributed with broad or poorly defined properties such as silicon supply or paramagnetism. In other cases, suppliers may be unwilling or unable to provide a clear nutrient analysis of what is being applied, instead suggesting that outcomes are driven less by nutrient quantity and more by forms of “biological activation.” These claims require the same level of scrutiny as any other input — namely, whether they deliver consistent, measurable improvements in production.
A practical test of any system is the outcomes it produces. Farmers should be able to ask: how many operations using this approach are consistently performing at the top end of production for their environment? How many have sustained those results over time? These are the measures that matter — not the claims, but the results.
The intent of the platform is to operate within this framework of measurable, repeatable agronomy. It is not designed to promote or dismiss alternative viewpoints outright, but to provide a consistent and transparent application of methods that are well understood and demonstrably linked to production.
Where new approaches — including those based on biological activation, alternative materials, or emerging interpretations — can meet that same standard, grounded in evidence, repeatability, and real-world outcomes, they remain open for consideration.