Yesterday, I mentioned that Steve Solomon's health improved when he spent six months in Fiji eating nutrient-dense vegetables.  The obvious question is --- why isn't all soil as good as the stuff in Fiji?

When it comes to soil minerals, you need to understand both rocks and rain.  The bedrock that slowly dissolved to make up the soil in your garden will determine which minerals were there to begin with --- some rocks are more well-rounded than others.  But even if your rocks are perfect, lots of rain can still wash those nutrients out of the earth through a process known as leaching.

As with rocks, not every area is equal in terms of leaching potential.  Hot, dry areas like the American southwest have little or no leaching because all of the water that hits the ground is sucked up by plants and transpired back into the air through their leaves, or simply evaporates from the earth's surface.  At the other extreme, New England soils are strongly affected by leaching because cold weather keeps water in the ground once it hits, so water tends to gush through the topsoil and into the groundwater, carrying minerals away with it.  In general, most of the soils in the eastern United States have been depleted by leaching unless careful stewardship has kept organic matter levels high at all times.  (Humus holds onto the same minerals that rain tries to wash away, keeping them cycling even if soils are flushed with water.)

Another factor to consider is age of your soil.  Young soils have lots of minerals, but as soil ages, the rocks dissolve and stop adding extra nutrients to the soil.  In addition, the cation exchange capacity of soils tend to degrade over geologic time.  Here's where the southeast is even worse off than New England --- we haven't had glaciers down here recently to top off our rock reserves, so many soils are old and low on minerals.

Assuming you aren't as lucky as folks in Fiji, you'll need to remineralize your soil to get it back in balance.  This is why Solomon is down on the compost-cures-all-ills approach to gardening.  As he explained: "Fertilizing a garden by composting local vegetation and animal manures derived from that same kind of vegetation will only magnify the regional soil imbalance."  Time to get scientific and figure out exactly what your unique soil really needs.

This post is part of our The Intelligent Gardener lunchtime series.  Read all of the entries: The Intelligent Gardener Why soils need to be remineralized Soil cations How to fill out Solomon's soil analysis worksheets Using Solomon's worksheets to determine soil additives Do wood and straw raise soil potassium levels? Can you have too much organic matter in your soil? Clay, humus, and CEC Managing blueberry soil micronutrients Excess phosphorus in the soil

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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.



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