View Single Post
  #7  
Old 11-21-2013, 06:34 PM
Victorsaur Victorsaur is offline
LawnSite Member
 
Join Date: Feb 2011
Location: Asheville, NC
Posts: 78
Quote:
Originally Posted by Kiril View Post
From your link.

http://www.soil.ncsu.edu/about/century/soilacidity.html
The procedure for measuring exchangeable Al+3 is not well suited for routine soil testing procedure. For this reason a buffer solution pH 6.6 is used to measure extractable acidity (Ac) in North Carolina soils. The buffered solution extracts both exchangeable Al3+ and the pH dependent acidity (H+) which becomes ionized up to pH 6.6. The lime rate to apply is calculated with the following equation.

tons CaCO3 / acre = Ac [(desired pH - soil pH) / (6.6 - soil pH)]

The desired pH for a soil is the pH at which the activity of Al+3 is neutralized. The effect of soil organic matter in decreasing the activity of Al+3 has been taken into account by establishing desired pH for each of three classes of soils (mineral, mineral-organic and organic) based on their organic matter content. The desired pH at which exchangeable Al+3 is essentially neutralized is 6 for mineral soils, 5.5 for mineral-organic soils, and 5 for organic soils.
Furthermore, without a value for Ac the formula is worthless.
Ok, thanks Kiril. For all values of desired pH less than 6.6 this formula makes sense.
Reply With Quote
 
Page generated in 0.04074 seconds with 7 queries