Weeds
and What They Tell Us
is a newly-released, lightly-edited version of Ehrenfried Pfeiffer's
book of nearly the same name (without the "Us") from 1970.
Unfortunately, this little book didn't live up to its promise,
especially given the high price of $13 for a 90 page text. I
could ignore the typographical errors, but the arguments are scattered
and somewhat contradictory.
The intriguing part of
the book is pretty much covered by the title. Pfeiffer believed
that the particular weeds found on our farms are signs of improper
management: "Weeds are indicators of our failure." A single plant
doesn't tell us much, but a suite of plants in the same category or an
increase in numbers of a certain plant is a sign of one of three big
problems:
The trouble is that I'm
not sure Pfeiffer's categories entirely work, especially since later
sections of the book suggest certain plants are indicators of other
soil problems. I'm also not a fan of his solutions to weed
problems, which seem to consist of lots and lots of tilling and some
chemicals (along with less problematic but rather obvious techniques
like hand weeding, mowing when flowers are just pollinated, draining
wet ground, planting cover crops, and adding compost and lime if
needed).
In the end, I'm still
waiting for a good book on this topic, so if anyone wants to go out and
observe weeds, I think your treatise would be well-received.
Meanwhile, for the rest of you, I recommend checking this book out of
your library (or just reading my summary above, which hits the
highlights).
I love observing weeds, and I'm fascinated by the idea of getting clues about the land based on what is growing wild, but if I write a book on the topic it probably won't be out for quite awhile. I'm not too confident with what I've observed. I also think it's tough to generalize because there are so many factors involved.
On our property, we have infestations of a plant called "tea weed" (Sida rhombifolia), johnsongrass and curly dock in an area that was overgrazed by the cows. It's hard to say whether the mucky, overgrazed ground is the reason those specific plants are there, or more likely just the fact that 30 years worth of weedy hay in that site (combined with the fact that the soil was exposed from all the tromping.) I can say for sure that concentrating animals and weedy feed in an area will lead to some kind of weed problems, but I don't know if it's always as predictable as we would hope when it comes to specific plant species. For one thing, we have horse nettle in that area too, and it's soft, boggy, rich organic soil-- nothing like a hardpan or crust.
If you're going to go around and study your weeds and try and give guidance as to what they mean, I think you'd need a pretty big grant, or a university / college / ag extension type of budget. You're going to need huge sample sizes, and you'd want to do soil tests, and data, data, data...
Sounds like fun, albeit rather expensive fun. Either that, or a doctoral thesis..........
Sara --- Yeah, that's where I think the author went wrong. He didn't look into all the possible causes of weed infestations and just latched onto one hypothesis.
Seth --- That's the thing --- the author of this book had all that support behind him (I think he spent his career studying weeds in some government capacity), and yet, he still didn't get there. I was envisioning getting a lot of data from backyard gardeners online --- ask them what their worst weeds are and pay for them to do a soil test, then crunch the data from there. Not that I'm gonna do it --- it's one of the dozen ebook ideas that are on the list but probably won't happen this decade.
Hi Anna,
I have found data scattered here and there, but have found no really useful data either.
I remember reading someone's statement that that cattails imply a lack of copper?
All that said, observations about plants are for sure a MUCH better indication of what is and is not in the soil than soil tests. Conductivity is perhaps useful as well?
I am wondering if a pot with "known good" soil (whatever that means) growing in the test field next to the same plant growing in the local soil might be a useful differential way to measure the soil's ability to grow a plant(s)?
Maybe a series of different plant types as above would be pretty useful though one would have to wait a few weeks to get any data?
Also, it is hard to control the subjective part of the experiment.
One of our well known consultants says he grows groups of plants in his greenhouse and looks for growth without large variations?
John
Do we need to analyze the weeds to tell if our soil is dry, crusted or poorly drained? As Yogi Berra said, "It's amazing how much you can observe by just watching." As I said in a recent comment, only the pro farmers have to strive for maximum efficiency. With a small garden and easy access to water, I let the weeds grow after my crop plants have reached a few inches tall. They help shade the soil, slowing evaporation and may help bring deeper nutrients up to the surface. Every few weeks I just go weed by grabbing handfuls and letting them drop as green compost. My yield is adequate for my needs.
That table in your Weekend Homesteader about nutrient values for various weeds was an eye-opener for me. Dandelions seem to be the SuperWeeds full of cations that I'm going to harvest and throw on my compost pile next year.
Doc --- It's true you can tell a lot about soil without paying attention to the plants, but plants do make a good indicator if you're looking at uncultivated ground and want to make snap judgments. I already use simple things that way, like sedges usually mean at least seasonally wet ground and broomsedge means poor soil. That's where I was hoping to use the information.
De --- I've read that blackberries are a sign of rich ground, but I think they're also just a sign of lack of mowing/grazing. Mark's been battling the blackberries in the gully this year, and we feel your pain....