AGRICULTURE BUREAU OF SOUTH AUSTRALIA MEDIA RELEASE
Tuesday 11 March, 2008
To P or not to P – Assessing the ‘P’ in Your Soil
Understanding phosphorous levels in soils has now become easier for growers due to an initiative by the Agricultural Bureau of South Australia.
As a result, growers can now purchase Soil Phosphorous Testing kits at a special price with the information provided by the kits enabling them to more accurately calculate fertiliser inputs.
Senior Consultant at Rural Solutions, David Davenport said with the costs of many phosphorous (P) based fertilisers reaching an all time high, efficient applications were essential to manage operation costs without restricting yield potential.
“Knowing and understanding soil phosphorous levels are essential to managing soil and nutrient quality in an efficient manner,” he said.
The kits include four sample bags allowing growers to analyse soil samples from specific parts of their property. Samples can then be lodged at Bureau collection points or Rural Solutions SA offices, which are sent to ACML/SASPAS laboratory in Loxton for analysis.
Samples are then tested for “Colwell P” and the Phosphorous Buffering Index (PBI). Colwell P is a measure that has been widely used in South Australia and elsewhere and provides an indication of the amount of P available to the plant (adequate levels are generally between 20-30mg/kg of available soil Phosophorous depending on soil type and crop grown).
Mr Davenport said PBI provides an indication of the potential for phosphorous to be tied up in the soil (reducing plant availability) or for phosphorous to be leeched through the soil.
“Essentially this index enhances Colwell P data and assists in making decisions on how much and what type of fertiliser to apply,” he said.
Chairman of the Advisory Board of Agriculture, Mark Dennis said the Board was excited about taking part in the initiative to provide the kits at a discounted price.
“We always encourage solutions that will help growers to become more efficient and cost effective,” he said.
