Wednesday, April 7, 2010

What are cations, why do I care.

Soil is so interesting, it makes me want to stare into space.
What are cations? 
They are ions that carry a positive charge of electricity (Reference 4). The common soil cations are calcium (Ca+2), potassium (K+), magnesium (Mg+2), sodium (Na+), and hydrogen (H+) (What is an ion, you ask.  An atom or molecule that has lost or gained a charge -by losing or gaining an electron).
Why do we care?
Many of these cations are nutrients for plants.  Different soils have a different capability to hold these nutrients (and other non-nutrients e.g. aluminum Al+3) and store them. This is quantified by cation exchange capacity.  The higher the exchange capacity, the less likely your favored cations will leach away from your beloved plant roots (and in tangential news, the lower your "base saturation", the less likely the mineral will give that cation up and let it go into the soil water solution for roots.  What is base saturation? I'll get back to you with an eloquent reminder, just... remind me).


  1. Hi! Love your blog! We have a compost thing/worm farm outside that we got at Sam's and have been putting all our food scraps into for about 4 months, a small tomato and herb garden that my husband has been working on, and have been debating getting chickens (not many, maybe 3 hens--in Round Rock you can have up to 5 as long as they're 25 ft away from a neighbor's home), so I'm psyched about your blog. :)
    It was great meeting you the other day!

  2. Ooooooh, a worm farm? That sounds cool. Is it working well? Any tips?

    Also, did you hear about the Austin Chicken Coop tour?

  3. PS It was lovely to meet you too! Thanks :-)

  4. Do you have sodic soils (really really high in sodium (ESP>6) and poor structure) in America?