Tuesday, March 12, 2013

Pensive Tuesday: Dishin' the Dirt

Well, actually, I mean topsoil, not dirt. Topsoil is the top 5cm of the Earth's dirty crust. It's full of microbes, broken down organic material, worms and ants, and hopefully, some water and not a lot of salt. It's where everything good in the plant world happens. And it's leaving us.

Not much topsoil here....
This picture is from near where I live. We used to have nice topsoil, not a full 5cm, but more than this. Our weather has gotten more extreme, with more drought, more monsoon-type deluges, and many more days with very high winds. Our topsoil has vamoosed! And buying more and laying it down over this dry silty sand doesn't help, as the winds and heavy rains just wash it away again.  My patches of garden with vetiver are doing much better. Vetiver has deep, extensive roots that really keep the soil locked in. So anchoring plants are great. Mesembs offer many species of anchoring plants; iceplant is a big soil saver in California. Carpobrotus edulis is one fine plant!

Carpobrotus, on the job saving your soil.
 Worldwide, the topsoil situation is pretty much the same as where I live. Drought is drying the topsoil, then wind or sudden deluges carry it away. "Black blizzards" of topsoil are getting more common, as they did in the 1930s in the US...

Historical photo of the 1930s US Dustbowl
And in Australia, their "Angry Summer" has brought fire, drought, and floods all together. Yeesh! Here's a picture from the floods in Queensland- you can see that topsoil just washing away to wherever.

Queensland flooding
No topsoil, no plants, no plants, no us.  It's not very fashionable these days to be thinking of, and talking about, dirt, but it would be wise to do so.  And I'm thinking of more ways to protect the little patch of dirt that's under my stewardship.  More vetiver and iceplant, anyone?? And how about a bag of worms?


  1. Ice plant was planted every where in San Diego when we lived there for erosion control, but mainly for fire prevention. I remembered playing ice plant wars in empty lots as a kid (where we break off the leaves aka spears and chug them at each other). But what I learned in my landscaping classes is that the ice plant is considered a highly invasive noxious weed in San Diego. Who knew? While it is good as a control for soil erosion and so-so for fire prevention, the common thought now is to stick with natives which don't spread all over and suck-up all the water from the other native plants.

  2. Thanks for your comment, E. It's funny how things change over time. When I lived in California, quite a few years ago now, the iceplant had been recently planted, and we had torrential rains every winter ("Pineapple Express")that could wipe out whole blocks of houses from landslides. The iceplant was a big hero then, as it really anchored the soil in a way nothing else could! I guess moderation is the key when it comes to introducing new species, isn't it? Drought was not a problem then in California, so no one was thinking through the fact that lots of ice plant could take the water from the native plants over time.