Healthy soil is crucial to growers optimising productivity, with testing an important component of fully understanding the limitations and potential productivity of soil.

Incitec Pivot Fertiliser’s (IPF’s) new Soil Health Testing Package helps growers measure and understand the physical, chemical, and biological characteristics of their soil.

The Soil Health Testing Package has already demonstrated the influence of different management practices in the Barossa Valley’s vineyards.

Soil samples were taken from two properties in June and analysed by IPF’s Nutrient Advantage laboratory. The samples compared the health of bare soil under one vineyard with straw mulch spread under the vines of the other vineyard, at a rate of 30 bales/ha.

Conrad Leeks, IPF technical agronomist, says the tests show some stark differences from the addition of mulch to the soil.

“In the vineyard where the straw mulch was spread, the active carbon is 547 mg/kg, which represents 3.9 times the amount in the bare soil system. As a result, the microbial activity is very much higher. Similarly, Total C and Total N are at optimal levels, as is C:N ratio – all key drivers of microbial activity.

“The straw mulch is helping to activate the soil microbiology, which is vital to storing and cycling carbon and nutrients and supporting plant health. Also, application of straw mulch helps build soil structure, which is important to water cycling, building resilience to extreme weather events, and reducing erosion risk,” Mr Leeks said.

The IPF Nutrient Advantage Soil Health Test Package has four measures that cover the physical, chemical, and biological characteristics crucial to soil health:

i. Physical – soil structure (dispersion and slaking - Loveday and Pyle test)

ii. Chemical – active carbon (labile) measurement

iii. Chemical – total nitrogen and total carbon ratio

iv. Biological – the soil microbial respiration (Solvita CO2) test.

Mr Leeks said that by measuring these four parameters, soil health can be better understood and incorporated into an overall farm management plan.

“Monitoring these parameters regularly can tell you how well structured and drained a soil is and how well it provides nutrients and water to plants and other organisms. This in turn will influence microbial activity and plant growth.

“A stable soil structure indicates that adequate organic matter is present in the soil, which assists in the binding of soil particles.

“A healthy soil has biological, chemical and physical properties that promote the health of plants, animals and humans while also maintaining environmental quality.”

To monitor the health of your soil, select SOIL HEALTH 1 as an add-on to your selected test code. You can also contact your local IPF technical agronomist to help understand more about soil and how to help improve soil health.

Comprehensive soil test results from the trial: