Skip to Content.
Sympa Menu

market-farming - Re: [Market-farming] Ingham on weeds (was Easy soil fertility test)

market-farming AT lists.ibiblio.org

Subject: Market Farming

List archive

Chronological Thread  
  • From: Nan Hildreth <NanHildreth AT riseup.net>
  • To: Market Farming <market-farming AT lists.ibiblio.org>, Market Farming <market-farming AT lists.ibiblio.org>
  • Subject: Re: [Market-farming] Ingham on weeds (was Easy soil fertility test)
  • Date: Mon, 01 Nov 2010 14:31:46 -0500

Dear Rivka, Thanks for giving me a run for my money.

Yes, many have defined "weed" as a plant you don't want. But I like Shoemaker and Inghams' definition better, an opportunistic plant that thrives where the crop won't, particularly in disturbed soil. Ingham says it's not just clearing off existing vegetation, but also, messing up the soil somehow.

It seems evolution is not just how long a plant has been around, but how complex it is and how much it depends on other life in the soil, air and water. For example, corn doesn't need insects to pollinate. Most Brassicas don't depend on micorrhizal fungi to thrive to bring them nutrients from decaying tree roots, etc.

Hmmm. I don't have better words than "primitive" and "advanced". Dr. Inham made a loud point that plants and soil has a succession of development. Plants, soil, insects co-evolved. She said "Early succession" plants like bermuda grass will thrive on an "early succession" soil, that is one with just a bit of fungi. She said .3 of fungi for each biomass of bacteria. But deciduous trees require a "late sucession" soil with five to 100 times more fungi than bacteria.

So, yes, what's "great soil" for one crop isn't for another. So if you kill your fungi with the rototiller or chemical fertilizer, then plant brassicas or other "early succession" plants.

Here is that part of my notes from Ingham's class.
· A billion years ago, all bacteria, no plants
· Then a few fungi, biomass ratio F/B = .01 (fungus to bacteria)
· soil good enough for weeds = F/B = .1
· early grasses bermuda F/B = .3
· mid-grasses & vegetables F/B = .75
· Late successional grasses, row crops F/B = 1.1
· Shrubs, bushes f/b = 2:1 to 5:1
· Deciduous trees f/b 5:1 to 100:1
· Conifer old growth f/b 100:1 to 1000:1

Soil evolved in the beginning, but as it is disturbed, then it must re-evolve. It takes time to build great soil.

Nan

At 12:43 PM 11/1/2010, Road's End Farm wrote:
But weeds are not some separate category of plant. Weeds are simply
plants growing where a human doesn't want them to grow.

Strawberries are a weed in the lettuce. Brambles are a weed in the
strawberries. Pasture grasses are a weed in the strawberries, the
lettuce, the brambles. All of them are also crops.

Many of the weeds we're dealing with were introduced to the area by
people who wanted to grow them on purpose -- often as food plants.

Amaranth, lambsquarters, etc. are "weeds of fertile soil" (and they
themselves are also grown as crops; though usually different strains
than the ones that show up on their own). I don't think there is any
such thing as soil that will grow good crops, but will not grow any
weeds: though soil in good condition for growing a specific crop (and
"good condition" for blueberries will be different from "good
condition" for corn) will tend to grow as "weeds" plants that want
growing conditions suitable for the desired crop. "Weeds" that want
growing conditions not suitable for the specific desired crop may
indeed indicate a problem; and those specific weeds can be discouraged
if the soil can be modified to better suit the crop; but other weeds
will then be suited to the field.

Modern evolutionary theory doesn't talk about "higher" and "more
primitive". It's true that some modern life forms are more similar to
ancient ones than others, but everything has been evolving for the
same length of time, after all. Different things are more suited to
different conditions, but that doesn't mean they are more "primitive".

The percentage of the plant energy that's in the roots is going to
vary from species to species and also vary with the time of year. I
very much doubt that a 6' tall okra plant in full bloom has the same
percentage of its energy in its roots as a carrot plant close to
maturity; or that a redroot amaranth in full midseason growth has the
same percentage of its energy in its roots as a Canadian thistle in
late fall. To say that all the plants being considered by the farmer
as "weeds" have 20% of their energy in the roots and all the plants
being considered by the farmer as "crops" have 75% of their energy in
their roots -- that can't possibly be accurate.

Most food crops have been bred for many generations by humans to
produce in the fashion that humans want them to. In the process, most
of them have become dependent on human intervention to do well,
because they've been bred, not for best survival in a wide variety of
conditions (including the conditions of competition from other plants,
of variable availability of nutrients, of variable availability of
water, etc.), but for best production of the portion of themselves
that humans want to eat. This doesn't mean that they're "less
primitive"; it means that they're adapted to a particular set of
environments: those enviroments in which humans are an essential and
helpful part of their ecosystem.

The "weeds" that grow best in a given field will be the plants that
are best adapted to the conditions in that particular field. To the
extent that the conditions in that field are as close as possible to
the conditions that the desired crop wants, the desired crop will have
less of a handicap relative to the weeds: so as far as that takes you,
excellent soils (again, excellent for the particular crop) will
certainly help the crop compete with the weeds. But there will always
be weeds that also do well in those conditions, whatever they are.



-- Rivka; Finger Lakes NY, Zone 5 mostly
Fresh-market organic produce, small scale



On Nov 1, 2010, at 11:59 AM, Nan Hildreth wrote:

Yes, Dr. Shoemaker, many weeds evolved to fit a niche: disturbed or
depleted soil said Dr. Elaine Ingham. Good soil thwarts weeds and
plant diseases, she said.

In her class last month I scribbled notes like mad for the 2 days
because this was so new to me. So it's good to try to explain it to
you.

Weeds are typically more primitive plants than crops, says Elaine.
Bermuda grass, she said is primitive grass that thrives when soil
life is primitive, that is, three times more bacteria than fungal
biomass. Weeds evolved to grow quick and produce tons of seeds then
die. Weeds invest only 20% of their energy in roots while veggies
invest 75%, fruit trees 80%.

Plants and soil biology co-evolved. Higher plants need higher soil
life, that is more fungus than bacteria. Higher plants feed soil
life with sugars from the roots. Half their energy goes into "root
exudates" of sugars, carbohydrates and proteins that nurture
symbiotic soil life. Ingham said plants putting out these "cakes
and pies" for symbiotic soil results in them forming a "castle wall"
around roots.

So you can grow more crops less weeds if your soil life is thriving
and mature instead of abused.

Weeds also co-evolved to thrive where there is too much fertility
she said. Thistle, she said, needs 50ppm nitrogen to even
germinate. Nutsedge 10 ppm. But unlike veggies, they thrive if
fertility comes in "pulses" for example, people throwing out
fertilizer now and then. Johnson grass, dandelions too, she said.
Weeds also like bad compost better than veggies. That is, compost
that got too hot from too much manure, went anaerobic, and looks
ashy or grey, she said.





_______________________________________________
Market-farming mailing list
Market-farming AT lists.ibiblio.org
http://lists.ibiblio.org/mailman/listinfo/market-farming

Market Farming List Archives may be found here:
https://lists.ibiblio.org/sympa/arc/market-farming/
Unsubscribe from the list here (you will need to login in with your email
address and password):
http://lists.ibiblio.org/mailman/options/market-farming

Nan Hildreth, Houston 713-842-6643
www.HoustonClimateProtection.org

Make Soil, End Global Warming

"We could end global warming if we restored the fertility in the soils in the state of California." Dr. Elaine Ingham, www.soilfoodweb.com

"...global warming can be reversed by restoring biodiversity in the soils and in the ocean. ... There is enough land to sequester this carbon and it could be done in a decade or two. ... Now that the Oil Age is coming to an end, we are entering the Soil Age. " http://groups.google.com/group/soil-age

"... a 1.6% increase in organic content of soils humans manage would restore atmospheric carbon dioxide levels to normal." says Allan Yeomans in http://www.youtube.com/user/AllanYeomans1#p/a/u/0/-o2N6vJDLpE Free download of his book http://www.yeomansplow.com.au/priority-one-contents.htm

"Soil is the new frontier" Eaarth by Bill McKibben




Archive powered by MHonArc 2.6.24.

Top of Page