this threads been a bit slow heres some links to read on, little bit of this little bit of that nothing in particular.
http://www.soils.umn.edu/academics/classes/soil3416/organic_fertility.htm
http://www.suite101.com/article.cfm/organic/44253
http://www.soils.umn.edu/academics/classes/soil3416/organic_fertility.htm
http://www.suite101.com/article.cfm/organic/44253