Saturday, April 07, 2012
how to analyse soil by looking at weeds
One of the subjects I'm really interested in is how analysis soil composition by looking at weeds.
Farmers spend untold amounts of time and/or money augmenting the soil. Put some chicken manure in the soil, you need to sweeten it with lime. Many growers are concerned with NPK, and neglect trace minerals (which are just as important).
Then there is the soil testing industry. You can buy home kits that tell you the basics, or you can send out soil samples to some far off lab for a full evaluation. This can range from a few dollars to several hundred.
Chemical analysis of soil is such a new thing; started less than 200 years ago. Yet, people have been growing food for a little longer than that. So, how did they tell when to add manure or compost, or wood ash, or...?
I've seen references in the old household and farming manuals to analysing the soil by looking at weeds. This is especially helpful if you are thinking of buying some new land. You have a look at the lay of the land, dig in the dirt a bit to determine drainage and check out the weeds. Easy!
Only problem, it was so easy, that the writers I've read didn't bother to write down what different weeds tell us about the soil.
It's not just how sweet or sour the soil is, but also what minerals, drainage, how much loam, sand, &c. There is so much you can tell by looking around you and seeing what plants thrive naturally.
But to find a comprehensive list of them all.... ah, that's my dream.
Slowly complaining one of my own by observation, but I would love a more scientific source of information.
Some acid loving plants:
Stinging Nettle (ouch - leaves sting) - loves soggy ground, with a bit dryer in the late summer/fall
A kind of dead nettle
Dock (make a paste by mashing up the leaves and put it on your stinging nettle sting to reduce the ouch) - deep root grows as companion to stinging nettles
Burdock (yummy! don't weed this please, I'll eat it all in the fall) - loves old pasture, doesn't seem to care about drainage at all.