Healthy soil and sustainable growing

[Dieter Brand <diebrand@yahoo.com>]

Bobby,

I have clay soil, hence I don’t know to what extend my experience can be applied to your situation. In the South of Portugal, were I live, we have extreme arid conditions during the summer months, meaning, not a single drop of rain from May through September with temperatures of around 100 F in the July/August period.

By improving my garden soil and using mulch, I was able to reduce irrigation by about 80% in 5 years. Last year, I used on average 1/2 litre for 1 m2 per day, which I was able to take from the surface water resources available on my property without pumping up any groundwater. On one field which hasn’t been ploughed for the last 12 years, I detected humidity near the surface even after two months without rain and without any irrigation at all. The field was still green after my neighbour’s field (ploughed every year) had gone dry for a long time. Even without humidity many plants can survive if the soil is crumbly and if there is plenty of organic matter.

With sandy soil too, the most important thing is to increase organic matter. It is best to leave it at the top without turning it under. When turning under green manure, due to erosion and oxidation, more soil and nutrients may be lost than gained. Select the plants (cover crops, weeds, perennials, etc.) that will grow best under local conditions without irrigation. Cut them, shredding coarsely when necessary, and leave the residues as mulch on the surface. If you cover a green mulch with a mulch of shredded branches etc. you can protect the greens especially during dry conditions, and by the time the woody mulch starts to decompose you have already covered it by another layer the following season (Gilles Lemieux in Canada did some research on using shredded branches). After some time, an organic layer will form at the surface protecting and enriching even sandy soil.

Regarding irrigation systems, after 10 years of experimenting with sprinklers, mini-sprinklers, drip systems, etc., I have come to the conclusion that “no-irrigation” is the best form of irrigation. I’m not quite there yet, but I keep on trying. In the meantime, I simply use the open end of the garden hose, using my thumb to modulate the water jet into a smooth film which lands softly on layers of mulch. Watering different plots in turn once or twice a week, this doesn’t take more than half an hour every day for a 1000 m2 veg garden. Setting up and maintaining automated sprinkler systems takes a lot of time and invariably involves loss of water even with drip lines. Manually, you can give each part of your garden just the right amount of water.

Other strategies for saving water are: growing as much as possible during the wet season and selecting plants (beans, etc.) that will grow on little or no water for the dry season. In my case, the crops I can grow during the winter include: most cover crops and small grains, almost all root vegetables, cabbages and winter-salads, fava beans, green peas, etc.

I started to clear some of our land. About 30 acres completely overgrown after decades of neglect. One method that proved to be very successful is to throw the seeds (small grains, cover crops, etc.) right into the shrubs. Subsequent cutting/shredding (in one operation) of the shrubs will cover and protect the seeds like a carpet of mulch. The woody mulch together with the new green and the root mass already show signs of improving soil quality after only a couple of years.

I also started collecting stones and logs for building numerous little barriers to prevent water from running off (look for “the man who harvested water” on the net).

Regards,

Dieter Brand, Portugal

Bobby G <bobbyg53211@yahoo.com> wrote:

> Hey folks, the area i live in is called the "Central
> Sands" of Wisconsin.
>
> the problem of soil retention is in the extreme here. 
> driving down I-39 towards Madison, WI, one passes
> signs that say: "WATCH FOR BLOWING DUST OVER ROAD."
>
> there's a billboard right there that says "WELCOME TO
> THE CENTRAL SANDS IRRIGATED VEGETABLE AREAS"
>
> i passed through a dust storm in that area once. the
> air turned a sickly yellow.
>
> that's what's left of the sandy topsoil blowing away.
>
> meanwhile, the irrigators were running just a couple
> miles away, spraying water everywhere, not having much
> effect on the loss of soils.
>
> so, this discussion is of great interest to us as we
> set out to find land for our land co-op. the
> predominant soils in the area are sandy. i don't
> think double-dug beds are going to be needed. rather,
> the cover-cropping, no-till, and heavy mulching with
> drip under the
>  mulch seem to offer the best ideas i
> hear on this list. irrigation as they practice it
> here seems utterly mad to me--all that water just
> evaporating into the hot winds...
>
> thanks for all the info, everyone!
>
> bobby g
>
>
>
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