Re: No-Till
Cyndi,
It sounds like you got great results from your "no-till". (I hope you saved the
dirt from the sod you cut out - in this locale that top few inches is the best soil
you have, and the only thing approaching "topsoil".)
When your finished, it sounds like you have a soil that you can keep moist, but it
is still clay underneath your layer of organic material. A lot of plants really
don't do well in clay; I'm not surprised that Bett' s roses did fine - a lot of
roses and most trees of that family do OK with their roots deep in clay. Keeping
us on topic of mediterranean plants, I wonder what kind of surface soil
predominates in the rest of the mediterranean climate. I think the principal
reason we have so little loamy topsoil here, is because with the light seasonal
rainfall, there isn't enough year round moisture to allow for soil buildup through
decomposition of the plant material on the surface, and that the growing season is
so short, thus not producing (in the grasslands) a lot of annual vegetative
debris. Even in our heavily forested areas, there are only a few inches of humus
on top of the subsoil.
I think if you had used mostly wood products (such as chips, ground bark, etc.)
instead of manure, your amended soil would have stayed friable, and not dried into
brick. The wood (especially redwood bark, which is available here locally) does
not break down as fast, and the wood fibers (lignin?) persist in the soil for a
long time, keeping the soil from sticking together, and maintaining air spaces.
(It really helps to mix in gypsum in quantity, as said by Sean). I agree you have
to mulch to keep the soil moist, regardless of whether you amend it or not. And I
have used a LOT of woody organic material in my soil amendment. When I first moved
here, I followed the advice of garden columnists, etc., who advised that you should
add about 1/3 of organic material to the top 6" of soil and rototill it in. It
only took one season to learn that this accomplished almost nothing. I use about 2
parts organic material to 1 part of the clay soil. (Like Sean said, the soil has
to be of the right moisture content before you try amending it, which is why if you
want to do it in the winter, you place plastic over it to keep from getting to
wet.) For individual planting beds, I have even moved the adobe aside, removed a
foot of clay beneath, and replaced the adobe amended with nitrolized redwood. Even
unmulched, the soil stayed friable. I have found that even California natives such
as Arctostaphyllus and Ceanothus get a much better start if planted in a soil well
amended with bark. They appreciate the better drainage.
Michael, I agree with you on rhododendrons (hardly a mediterranean plant) - I would
never plant a rhododendron in the ground here, but plant them above ground, in
their own bed of firbark.
Cyndi Norman wrote:
> I have done an experiment comparing no-till to till.
> Plot 1: sod removed with shovel. Soil dug up to about one foot and mixed
> with horse manure. Left to sit all fall and winter.
> Plot 2: sod removed with shovel. Soil untouched except for a very little
> bit when the sod was removed. Same amount of horse manure (same source)
> put on top of the soil. Leaves also put on top. Left to sit for a couple
> months of the winter.
>
> Results:
> Plot 1 was hard and in places like bricks.
> Plot 2 was soft and moist everywhere.
