Brynk wrote:

Damage the soil structure?
Please, explain this.

... Tilling wet soil damages the soil structure, and shouldn't be done...




Since this query was posted yesterday and had no responses, I have to
assume there's no generally known good information out there about soil
structure. If that's not the case, lets hear it.

Disclaimer: I'm not a soil scientist nor an expert on soil structure.

My $0.02:

Soil structure is two things. The first is the obvious structu Dig a
hole and you'll pull up loam (hopefully). A little further down it will
be another type of soil, maybe just mineral soil with less organic
content. Further down it might be clay. There are wide local variations
in this kind of structure. The material making up the soil is classified
in "soil associations", which use the organic content, the region of the
sand/silt/clay triangle
(http://web.mit.edu/dryfoo/www/Info/soil-grid.html), and the number of
stones (important here in New England) to differentiate between types of
soil. Surveys of soil associations have been done by the USDA and they
have maps available of most if not all areas for which agriculture is
feasible.

The second is the way the individual soil particles associate with each
other. They may clump together in large lumps or they may not associate
with each other at all, in which cast you have dust. Moisture has a
significant effect on this structure.

Tilling will alter the soil structure, no matter whether it's wet or
dry. However, damage is a subjective thing. If you are tilling down into
the clay level, the alteration may "improve" the soil by increasing
drainage. If the tilling during wet periods contributes to compaction of
the soil it's degrading the soil for purposes of growing things. Tilling
in average to moist soil moisture conditions will loosen the soil and
contribute to drying out. Obviously, what will happen will depend
strongly on the composition of the soil, whether it's high in organic
material, or high in clay, or high in sand.

Here, the terms improvement and degradation are assessed on the basis of
the use of the soil for growing things. If you are gardening (why else
would you be looking in this newsgroup?) the above terms are presented
for you. If you think that natural soil structure should be preserved
above all, then you are probably a hunter-gatherer and your outlook is
vastly different from most people on the planet. Please give us your
opinions.