Soil health can be like Human health in many ways

Soil health begins with improving the physical environment in the soil and this brings many important benefits for the gardener.

However, it is important to realize that soil health relies on a balance that is actually made up of three components - Structure, Nutrients and Biology. Each of these has its own balance relationship and must also be in balance with the others.

This is the basis for the Mikhail soil balance system, but one of the biggest differences between this and earlier balance systems is that it begins with Structure - not Nutrients! In other words, it first improves the friability and other aspects of the physical environment within the soil, upon which plants and all other soil organisms depend.

To put it another way, the Mikhail system looks at soil health in the same way that you or I would look at a balanced and healthy lifestyle for ourselves. That is, to have a healthy human, you must first begin with a strong skeleton. To have strong bones we need Calcium, Magnesium and Phosphorus – in the right proportions. Likewise in soil, the proportions of Calcium, Magnesium, Sodium, Potassium and Hydrogen are important for the basic structure or ‘skeleton’ of the soil.

But, a human being is more than just a collection of bones. The skeleton supports the body and the development of strong muscles. This process requires Carbohydrate, Protein and Fat in the right proportions, throughout life. Likewise, soil health is built on having Nitrogen, Phosphorus, Potassium and Sulphur available to plants in the right proportion throughout their growing season.

In addition, we see the interaction between these two components when we look at people of different sizes. Imagine, for instance, trying to build a 'Schwarzenegger' body on a 'Mr Bean' skeleton. It is just as ludicrous to try and build soil with only fertilizer - the 'body' of the soil must be proportional to its 'skeleton'.

Of course, human health relies on more than just carbohydrate, protein and fat; we also have requirements for various vitamins and minerals - in the proper amounts. In similar fashion, productive soils must provide plants with the complete range of Trace elements in suitable quantities.

Still, we all realize that healthy people need even more. We need the right balance of ‘good bacteria’ on our skin and in our digestive system to help us take up the nutrients we require and help protect against infection. Soil health is no different and the biological component of the soil also needs to be balanced for similar reasons.

And just as the requirements for humans will vary somewhat for each individual and at every stage throughout life, so too, each soil will have its own individual needs and characteristics, while the requirements of plants will alter throughout the growing season.

Cation Balance

In terms how we manage sustainable production, the Mikhail System focuses on cation balance (the soil skeleton) as the most important step in developing soil health. This optimizes soil structure and ensures the greatest possible availability of all nutrients.

For proper soil health, the desired cation proportions (as percentages of the Adjusted Exchange Capacity), as well as the Calcium Magnesium ratio , are as follows:

Adjusting these proportions requires the application of materials such as Lime, Dolomite and Gypsum in the appropriate amounts. But how can you work out which material (or combination of them), as well as the 'approapriate' amount to use?

This is where the Hydrogen becomes so important. When the early researchers (like Albrecht) were developing their soil balance systems, there was no test for exchangeable Hydrogen in the soil - only the estimate of total hydrogen expressed as "exchangeable acidity". So these scientists developed a pH-based estimate of the exchangeable Hydrogen that 'Albrecht' laboratories continue to use today.

However, a reliable test for exchangeable Hydrogen in soil was developed in 1960 - just as Ted Mikhail was beginning his research - and this showed that in places like Australia, Africa and other countries with very old and fragile soils, the pH estimate simply doesn't work.

Ted Mikhail's laboratory (SWEP) still uses this test, but in the course of his research Ted also found it necessary to take the soil organic matter into account. Organic matter is intrinsically high in exchangeable Hydrogen, but will be degraded if this is balanced with Calcium in the same way as the mineral fraction of the soil.

To overcome this problem, Ted developed an adjustment for the measured amount of exchangeable Hydrogen, relative to the organic matter percentage. He calls this the Adjusted Hydrogen and combining this with the amounts of exchangeable Calcium, Magnesium, Sodium and Potassium gives the Adjusted Cation Exchange Capacity - upon which the proportions above and the appropriate amounts of any required Lime, Dolomite or Gypsum should properly be calculated.

The practical outcome of all this is that instead of looking for places that have good soil, you can work with what you have and easily improve almost any problem soil.

Once the cation balance has been corrected, providing balanced plant nutrition will mean ensuring the plants you are growing have the necessary amounts of all the nutrients they require (and - ideally - no more) throughout the period of their growing season. Of course, the soil will supply much of this requirement, so the only nutrients needed (as fertilizer) will be those that are in short supply in terms of the existing levels in the soil.

Don't rush to put on fertilizer though. Lime, Dolomite and Gypsum need time to improve the soil in ways that assist in making nutrients available to plants. Be sure you allow at least six months between cation balancing and fertilizing. However, a question often asked here is "Should I use Organic or Chemical fertilizer?"

Soil Biology

Now all that remains for complete soil health is to stimulate the activity of those organisms that are needed to help facilitate the changes we have set in motion. Soil Biology as an aspect of soil health is a topic that needs a page of its own, so click here for more information.

Further Reading and Useful Links

Using kelp, humic acid and fish emulsion, etc.
Here you can also read about the results of recent research showing the effects of various 'Bio-active materials' like Kelp extracts, Fish emulsions and so on.

Which is best - Organic or Chemical fertilizer?
It is not so much what you use, but how you use it. Having said this, organic fertilizer causes less disturbance to the biological community in the soil.

You can also keep up with issues related to soil health by subscribing to our email newsletter - The Food Gardener.