Soil Tests Can Help Drive Fertiliser Efficiency as Prices Skyrocket

Fertilizer costs are at 12 year high and supply shortages are impacting farmers across the country.  Now is the time to take advantage of soil testing to ensure that soils are optimally balanced to maximise nutrient availability and cycling.  A good soil chemistry test is really worth its weight in gold and can guide soil and fertiliser management for the year ahead.

Soil balancing is necessary to improve soil performance and efficiency and regular soil testing is recommended. Converte use a random sampling methodology sourcing 12-16 points in a paddock area of 5-10 ha, to a depth of 20cm and mixing the soil to provide a composite sample.  Provided you pick a representative area of the paddock this technique works well.

Converte send soil samples to independent laboratories for a range of chemical parameters under an Albrecht / Reams soil balancing test. The focus is primarily on addressing key imbalances that could potentially impact nutrient/fertiliser efficiency.

Our first focus on a soil test is the Cation Exchange Capacity (CEC) and Calcium: Magnesium balance.  This has a huge bearing on soil health, ability to hold water and to transfer nutrients to the plant.  The CEC is a measure of the soils ability to hold and transfer nutrients and in a well-balanced soil this will be around 12.

In a balanced soil the Calcium percentage should be 60-70% and Magnesium 10-20%.  Too much calcium and your soil will become too loose and lose moisture. High rates of magnesium cause the soil to become too tight and won’t allow moisture to penetrate.  If the balance is right the pH will be around 6 to 6.5.  Improving the Ca: Mg balance requires careful consideration with your agronomist, liming at high rates can choke the soil and sandy soils may need a dolomite limestone to add additional magnesium.  Take care with this decision as it is critical to your soil’s potential for optimal performance.

Second on the soil test for us is Phosphorus (P) and we like to know the plant available P and the total P.  We often encounter farms with several years of in ground phosphorus and this can be gradually released by improving soil balance and biological function.  This will affect how much P you apply in the form of super phosphate or softer rock phosphate and can lead to considerable savings.

Thirdly we look at the trace elements and in particular Boron, Zinc, Copper and Manganese.  Traces play important roles in plant health and function with deficiencies impacting both quality of crops and total yield.

Finally, the Soil organic matter is the engine room of the soil that keeps the system functioning with nutrients flowing.   Ideally, we want soils with 3-4% organic matter or more, but if we are managing soils with 2% or less, then adding some additional organic matter (if economical) is well worth considering.

Once balanced, soil has an active biological component and soil biology can access far more nutrients than any farmer could ever add.  Soil contains an extensive army of microbiology ready to provide nature’s free services, including water and nutrient management. To get the most from soil biology, it requires protecting with appropriate cover and feeding.  No till farming with year-round cover cropping is one means of protecting soil biology and building soil carbon.  However, any farming system needs to be balanced with appropriate fertiliser and chemical input.  High chemical inputs will result in sub optimum soil biology.   In the end it’s all about balance.  

For more information www.converte.com.au