permaculture

[Toby Hemenway <toby@patternliteracy.com>]

On 8/16/2011 4:24 AM, m_astera wrote:
> There is a myth, a very popular one, that all one needs is "more organic
> matter" to turn any piece of ground into a fertile paradise.
> 
> Among others promoting the myth are the Rodale organic crowd,
> Biodynamics, Permaculture, Fukuoka's fans, and Ingham's SoilFoodWeb. The
> soilfoodweb organization has probably taken it to its furthest extreme,

It's not that it's a myth, because it's often true. It's just not the whole 
story. But it tends to be true so often because so many of our soils have 
been depleted of their organic matter. Tillage, chemical fertilizers, 
addition of urine or other high-nitrogen materials to soils, and many 
practices of agriculture deplete soil organic matter. So in many, many cases, 
the first and best thing you can do to restore soil health is to add organic 
matter. I know there's been a certain backlash to this because it's been 
over-simplified, but in many cases the results of adding OM are more dramatic 
than anything else you can do. By now, OM has become the limiting element for 
proper soil function in most of the world's soils.

If you don't have SOM to hold onto minerals like Ca and Mg, adding them is 
just a short term solution, even in the form of rock dusts. Rock dusts are 
more persistent than soluble chemical fertilizers, but both are just ways of 
delivering minerals to plants (or microbes). Rock dusts need microbes to 
break them down and keep them in the soil. No SOM, no microbes, no mineral 
retention. Some clays are good at holding minerals, but SOM is far better. 

So in most cases, adding OM is the first and most effective step, and 
refinements like rock dusts come later.

Toby
http://patternliteracy.com