Some of the background basis for the way we look at overall soil health including biological considerations is based on the learnings from Professor Albrecht and the “Albrecht Model” and Professor Justus van Liebig’s “Law of the minimum”. Professor Albrecht developed the concept of Cation Exchange Capacity (CEC) which is essentially information related to the soil’s character/fertility and thus its ability to hold the nutrients required by plants along with its capacity to protect groundwater from cation contamination.
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There are many different ways to look at the overall soil health, various testing methods and ways to interpret this data. We focus on assisting producers to understand the overall options, what it all means and what may be the best fit for their particular management strategies.
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We are always in a constant state of change as new science becomes available, focus on other methods of testing and producer interests change and will continue to develop our knowledge to better assist farmers to decipher their own on farm data; to enable them to make fully informed management decisions
General Soil Sampling Method / Process
Sampling methods vary between agronomists and suppliers however VAES utilises Department of Primary Industry Guidelines/“Guidelines for fit for purpose sampling” developed by Cameron Gourley and David Weaver.
This provides the background rationalisation for sampling plan development/number of samples according to paddock size etc.
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Sampling programs also largely depend on what the producer is looking for. 1) Are they looking to compare a performing and non-performing paddock or 2) A general average of a paddock or two or 3) different land types/systems within one paddock or across a property or 4) previous sampling method and data for comparison.
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We can sample and split samples at any depth down to 2 metres or more. We have various types of equipment and are ready to face any challenge we may find out in the field.
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From automated ute mounted equipment that splits up to 3 samples down to a depth of 90 cm (at any required depth) or Christie Engineering hydraulic gear mounted on ute/trailer that can take larger samples and to a greater depth, to hand held post rammer type probes that we may use in less accessible areas for example established salt bush plantings on marginal land that need a 4x4 motorbike to get to.
Soil Nutrition
Sampling Programs
Each Soil sampling program is tailored to the needs of the business so we may use various labs depending on the needs of the project. There are quite a few labs in Australia that are NATA Accredited (NATA is Australia's leading accreditation organisation) accredited and provide various options for analysis whether you are looking for general soil nutrient parameters, biological testing, or other methods of testing. For example Eurofins APAL, EAL, CSBP, Microbe Wise; and we will work in with the producers, consultants or preferred suppliers when required to provide the best tailored program for your particular situation.
​The minimum standard parameters to assess the overall picture for our soil nutrition programs are:
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​Phosphorus (Colwell), Potassium (Colwell), Sulphur (KCl 40), Organic Carbon (Walkley-Black), Nitrate Nitrogen, Ammonium Nitrogen, Electrical Conductivity, pH (water), pH (CaCl2), Texture (In-house method).​
Also Boron, Trace Elements (DTPA) - Copper, Zinc, Manganese, Iron, Exchangeable Cations without pre-wash - Calcium, Magnesium, Sodium, Potassium, Aluminium, Texture (In-house method), Phosphorus Buffering Index.​
Plus Total Nitrogen and Total P which helps to factor in nutrients that are available via or to microbial counterparts in the soil.​
We also now as standard practice factor in in-field biology tests whenever possible.​ Also to note that we have the highest accuracy when traversing to or saving new soil sampling points with top of the range GPS equipment and location and navigation systems to ensure we can get the best data for comparison at a later date.
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We can also factor in other methods of testing such as the Haney Test. The Haney test is a soil testing method that uses chemical and biological data to measure nutrients available to plants and microbes but also measures some soil health indicators such as soil respiration, water soluble fractions of organic carbon, organic nitrogen and their ratio.
