Agriculture Reference
In-Depth Information
that it gets the organic matter down into the soil where it can be broken down into humus,
whereas if it stays on top, more of the carbon is volatized into the air.
Other research shows that if no-till is used with sufficient existing biomass, both the
supply of nutrients and good soil structure can be maintained. This is especially true if
you've tilled in compost and green manures for the first couple of years to bring up that
biomass.
In the long run, I'm most likely to do just shallow tilling to a couple inches deep,
mostly by hand. The main reason you might do this shallow tilling is to lightly incorporate
the organic matter from a cover crop or from this year's veggies or compost, as this does
hasten decomposition and promotes more humus formation and less volatization of carbon
into the air. If you stay shallow, you won't have as detrimental an effect on soil structure,
dormant weed seeds, microorganisms, and earthworms. Even so, do this minimally and
carefully in order to limit the disturbance. There's generally no need to till in order to pre-
pare the garden for seeding, other than perhaps with a light hoeing.
Sometimes, I sheet mulch to prepare new garden beds. As we've seen, this involves
layering organic matter 12 or more inches high right on top of the grass or soil. It takes
longer for the organic matter to get down into the soil, but you don't cause drastic soil
structure damage. Many people have had great success doing this, but I mostly prefer to
do it when I know I have a decent organic matter content in the soil already. Something
else I sometimes do for fun is work on half of a garden with the tilling or double digging
method, and the other half using the sheet mulching method, to see which does better over
the years.
The other main reasons gardeners may till are: 1) to make the soil look fluffy and nice,
2) to allow more air and water into the soil, 3) to reduce weeds, and 4) to relieve compac-
tion. Tilling is generally a short-term solution for all of these. I'll now address each of
them in more detail.
1. One reason we can get rid of right away is “to make the soil look fluffy and nice.”
Not that the goal isn't achieved, but the goal is arguably unreasonable. We've
learned to think of bare, fluffy soil as being the most attractive “look” for our gar-
dens. I understand this — and tilling is a good fluffer-upper — but I also think
leaf mulch and other natural mulches are attractive. That's what you see in a
forest, not bare soil or several inches of bark mulch for that matter.
As organic gardeners, one of our goals is working with nature. It doesn't mean
we need to have a messy garden, but we definitely aren't going for cleanliness
like that of a living room floor. If you want to put a wood mulch on to make it
look tidy, it would generally be better not to use bark. Preferably a better type of
wood mulch would be from hardwoods, not softwoods such as cedar and fir.
