Re: the "no till" system
Robert Anspach wrote:
>
> I believe that the reason that no-till works is that we stop destroying the
> holes that the worms dig and provide them with all the food that they can
> eat. Every time we till we cut off their passage to the food on the surface
> and their chance for romance. When they can come to the surface to eat they
> carry the food down into the earth and leave it there as castings. Castings
> seem to be the answer to many of our problems such as White Fly, fungus,
> virus and many more problems. The proof is slow in coming and mostly
> anecdotal but there are enough stories to make one think there must be
> something to the worm castings story. Help your friendly worms. Stop the
> chemical fertilizer. Don't destroy their highways. Give them lots of food
> to eat and they will help you. This is my experience and is not the policy
> of the Master Gardeners or the Fullerton Arboretum.
Hi Robert
I agree that worms and their burrowing are responsible for a good part
of the open texture of good no-till soils, but they don't have to do all
the work on their own. Other workers who make burrows include such
things as ground-dwelling beetles, and further channels result from the
death and decay of plant roots. Moreover there are fungi which are
common in undisturbed soils which produce a sort of natural glue called
Glomalin which lines these passages and helps to keep them open.. Some
worm burrows can go remarkably deep. Two or three feet would not be
uncommon in dry areas where the worms retire to the depths to escape
summer dessication. By the way, not all worms come to the surface to
feed, only the night crawler group. The others find their food by
steadily eating their way through the soil and excreting it behind them
as enriched castings. As you so rightly say, though, chemical
fertilizers do them no good at all.
These relatively large channels made by worms and their co-workers are
known as macropores. They ensure that the soil is well-drained and
receives plenty of air and they doubtless also aid root penetration.. In
addition there is also a system of much smaller micropores which
apparently result from interaction between humus and the mineral
fragments. These pores act as a moisture store as they don't empty out
like the larger channels and they can also allow water from the deeper
layers to rise up towards the surface by acting as capillary tubes.
The analogy of a sponge is a good one in understanding the action of
these two types of pores. When a bath sponge has been soaked in water
and is set to drain much of the water will run out of it quickly, but
eventually the outflow stops. This means its macropores have been
emptied. Only if the sponge is then squeezed will more water flow out as
it is forced from the micropores.
One of the beauties of such a natural sponge with its glomalin pore
lining is that it has both strength and elasticity, so someone casually
walking over the surface does not simply crush it in and compress
everything in the footprint into a solid lump. There may be dints in
the surface when the feet have passed, but come back in a hour or so and
it will have all sprung out again, quite different from the fluffy
featureless mass left by digging which has to be so carefully preserved
from treading..
Moira
--
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata (near Wellington, capital city of New Zealand)
