SOIL tests should be used in concert with tissue tests to try to unravel the complex world of life beneath the soil surface.
This is the view of leading soil consultant and author, Graeme Saint, from Queensland company Nutri-Tech Solutions.
"Tissue testing is very important, almost more so than soil testing but you must look at the two together," Graeme told a series of soil health field days in Gippsland recently.
He urged farmers to develop an understanding of the ideal ratios, or balance, between particular minerals and nutrients.
He also stressed the importance of calcium and trace elements such as boron and molybdenum in optimising plant growth and animal health.
When a soil was in balance, the leaf analysis should mirror the soil analysis, he said.
"We subscribe to the concept of a balanced calcium to magnesium ratio (about 7:1) in the soil," Graeme said.
Calcium acted as a flocculant and opened up the soil to allow oxygen in, while magnesium tightened it up, he said.
"Oxygen is the single most important of all elements in soil biology," Graeme said.
Another factor governing soil health was organic matter, which ideally should be in the range of 4-10 per cent, he said.
Organic matter worked in concert with mineral balance, the importance of which lessened as organic matter increased.
"Soils with a high organic matter usually have a large number of organisms helping out with nutrient recycling," Graeme said.
Another important measure is cation exchange capacity.
"This tells you how much clay you've got, and clay together with organic matter holds on to leachable negatively charged and unstable anions - such as sulphur, nitrogen, nitrates and boron," he said.
