Homestead mailing list

["Karen L. Black" <karen AT plamondon.com>]

Rob asks:

> What's the rule of thumb for amount of lime needed to raise ph one point?

I don't know of a rule of thumb. It depends on how many hydrogen ions the
calcium ions need to displace (the "buffering capacity" or cation exchange
capacity). The more clayey a soil is, the higher the CEC. 

I know that my "silty clay loam" pastures, with a pH around 5.5, would see a
pH increase from 2 tons of lime per acre. One ton would be a maintenance
level, and more than three tons at once is not recommended. (This from my
pasture nutrition class several years ago). My instructor was keen on
hands-on, and suggested that we try several liming levels (i.e. parallel
strips at different amounts) to see what the pasture did best with. I'm
getting around to it this year.

If you have done a soil test, here is an explanation of the info:
http://www.gov.pe.ca/af/agweb/index.php3?number=74158. If you haven't, you
could try my instructor's method. One ton per acre is roughly 3/4 oz. per
square foot, or 4.5 lb. per 100 square feet.

Hope this is of some help,
Karen Black
Norton Creek Farm
Blodgett, OR