Paulo Ceccon (Udine University)

Martindale's Calculators

Mississippi State University

New Mexico State University

Earl C. Ellis (agroecology.org)

Juan Luis Rouanet M., Ph.D.
Natural Resources Dpt.
Agricultural Research Institute (INIA)
Carillanca Research Station, CHILE
phone 56-45-215706
fax 56-45-216112
jrouanet@carillanca.inia.cl