Soil Science has tended to focus strongly on understanding the mineral component of soils, yet agriculturally useful soils consist of minerals (ideally 45%), organic matter/biology (5%), air (20%) and water (30%) - all interdependent on each other. Studying one component in isolation can, and has, led to erroneous conclusions.

Nonetheless, a huge reservoir of knowledge has been accumulated on soil minerals and their likely interactions and expressions, taking us a long way down the road to helping us understand and appreciate soils and their role in the overall nutrition of the food chain, both below ground and above ground. 

Cation Exchange Capacity (CEC) and Total Exchange Capacity (TEC) are terms used to describe the mineral/nutrient storage capacity of a soil. It is based on the assumption that very small soil particles (colloids*) hold onto the bulk of the soil's nutrients.

Soil colloids tend to be negatively charged and like a magnet, they attract positively charged elements (cations) onto their surface. But soil minerals are not static, rather they are continually swapping places - or in other words 'exchanging' places. 

Paramagnetism is a real phenomenon that can be measured and explained by scientists, but is often relegated to the weird and fanciful in conventional agricultural circles.

The phenomenon was first named and extensively investigated by the British scientist Michael Faraday beginning in 1845; it was then applied to agriculture by Dr Phil Callahan. Interestingly, Boral quarries in Australia became aware of the benefits of paramagnetic material in agriculture during the 1990s and conducted a lot of research into the topic*.

pH is a measure of the hydrogen ion* concentration of a substance ranging from 1 -14. It is not a measure of the calcium/lime content of a material, or soil in this case!

The lower the pH reading, the higher the hydrogen ion concentration [H+], and the more acidic the soil. The higher the pH, the higher the hydroxyl ion concentration [OH-], and the more alkaline the soil. A soil pH of 7 is considered neutral, ie. [H+] = [OH-].