DEAR NEW FARM:
In this article: www.newfarm.org/depts/NFfield_trials/0705/weeds.shtml
on weeds and crop competition, do you also study the types
of weed growing and the effect different weeds have on the
crop? Do some weeds attract more beneficial insects? Do some
weeds supply better replacement minerals after tilling in?
Can some be a kind of beneficial living mulch discouraging
some pests and soil born infections? I am reading some books
on weeds, why they grow, what they say about the soil and
fertility of the soil, and how they can help bring good fertility
levels back to neglected and depleted lands. But I was wondering
about weeds as beneficial to the crop itself in an organic
system and if anyone had done any study on it.
Thank you for your time,
Great questions all! Once again we turn to our organic weed
control expert Matt Ryan. (Matt was the primary author on
the piece you sited in your question.) Here’s what Matt
had to say:
Thank you for your interest in our research at The Rodale
Institute! Yes, we do study the diversity of weed species
present in the experiment mentioned in the article. However,
we do not study the effects of individual weed species on
crop yields (we'll save that type of research for the land
grant universities). This experiment was designed to evaluate
the naturally occurring flora that encompasses multiple
weed species. If you would like to see a summary of the
work we have done on weed species diversity, please let
The next part of your message seems to focus on the potential
benefits that weeds may provide (correct me if I am wrong).
Certainly, different weeds do different things, such as
attracting beneficial insects, cycling nutrients, and stimulating
crop growth. One of the issues people face when trying to
retain beneficial weeds is that there are usually some bad
weeds that come along for the ride.
You are right on target when you say that weeds can improve
fertility levels in depleted soils, and it is a natural
progression to ponder the potential benefits these weeds
may provide to crops. While research has been done on this
topic, it’s still in its infancy. One study looked
at the effect of weeds on soil microorganisms and the potential
for weeds to supply crops with beneficial microorganisms
(Struz et al 2001). I have listed a few journal articles
that you might be interested in below. If you are interested
and cannot access them, please let me know and I will send
you a copy of each.
I am hopefulthis answered you questions, but if I came up
short let me know and we'll continue the discussion.
DEAR MR. RYAN:
Thank you so much for the articles you referenced—I
have a lot to read and learn (about all things related to
land)! Any actual doing of things has to wait until the house
is done (only a few more months) and I am living up there.
The study of how to use the land and its resources wisely
is a good use of time, so I study. What I find usable will
be in the providence of time and experience. Study will at
least make any mistakes I make well educated ones! My intentions
are good, so hopefully I will at least do no harm. ATTRA and
SARE have also been good resources for environmentally sound
and sustainable land use, as have the forums at New Farm and
Organic Gardening magazine. The generous nature of people
shines in the way so much information is so willingly shared.
us with comments, suggestions and questions.