[APWG] Native straw mulch still winning against weeds

[Craig Dremann - Redwood City Seed Company]

Dear All,

The rains in California in October started the germination of the annual
weeds that cover our state from top to bottom from sea level to about
3,000 feet elevation, and nearly 100% cover.  That has made weed
management and conversion of weedy areas back to solid native cover,
nearly an impossible task.

Our weed issue is especially important when managing the listed Endangered
species critical habitats that require grasslands to survive, which is our
most weed-infested biome, and where most of our Endangered species are
trying to survive in central California.

Fortunately California grassland weeds have been annuals, until the
introduction by the USDA/NRCS of Harding grass, and the introduction by
the nursery industry of Fountain grass and Pampas grass.  The USDA has
even worked on Franken-grasses, crossing European weedy species and North
American natives, to develop an ever stronger form of land-smallpox.

You can read about intentionally introduced weeds at
http://www.ecoseeds.com/juicy.gossip.six.html.

In my test plot in Palo Alto, I am using native grass Stipa straw to
eradicate the weeds.  Nassella pulchra or Stipa is a perennial bunchgrass,
and I am also using cut annual weed straw from the site, that you can see
a painting of at http://www.ecoseeds.com/art3.html.  So far, the straw, of
both the Stipa straw and the local weed straw, is working very well.

However, right at the edge of the test plots, Italian thistle seedlings
are coming up at the rate of about four per sq. inch and the annual weed
grasses are at about 8 per sq. inch, which equals a whole lot of seedlings
per acre.

You would think that all grass straws would act about the same, but there
is a big difference between the annual weed grass straw and the perennial
straw.

For the annual grasses, they need the organic matter and nutrients in the
straw for their seedlings ASAP, so that straw breaks down pretty fast,
like within the first couple of inches of rainfall.  The annuals weed
grass straws do not build up any soil organic matter reserves, because the
carbon is always either in the straw or in the growing plants, and never
gets sequestered in the soil.

However, the perennial native straw is much longer lasting, maybe up to a
year or more.  The prairie soils, or Molisols, were built up the soil
carbon that the generous perennial grasses sequestered with their roots
and leaves.  Every time I eat a slice of bread, I am grateful for the
generous perennial native grasses for creating the soils, where the wheat
was grown for my bread.

I am doing plantings of native seedlings in a mima-mound pattern in the
straw covered plot. Mima mounds are the bulb farming patterns of the
Pacific Coast Native American fields from 200+ years ago.   Geologists
have always wondered about what created these mounds, were they made by
giant gophers, or what?  It was Native American farmers, and if you go see
the mounds, you see the genius in their design.

Mima mounds were converted wetlands, where circular mounds about 8-10 feet
in diameter were build up a few inches above the water level and native
bulbs were planted and harvested.  The bulbs were growing in a drier soil,
but their roots would always have water.  Instead of bringing water to the
crops, you brought the crops to the water in California. You can see
examples of these mounds along I-5 north of the Weed airport, at the
northbound rest stop.

So the mima mound pattern in my Palo Alto plot, is a circular areas raked
free of the Stipa straw and planted with mostly California poppy seedlings
so far.  I will be updating my web page to show the current conditions of
the plot at http://www.ecoseeds.com/art3.html and a new painting will be
posted by the end of the month.

I would love to hear of anyone who is trying the native straw method on
weeds, especially in sensitive areas like Endangered Species habitats,
where you cannot use the older and more severe methods of grazing,
tilling, burning or herbicides to do weed control.

Sincerely,  Craig Dremann (650) 325-7333