Correlation between 1/3 atmosphere percentage and moisture equivalent in soils of northeastern Brazil

Abstract

This paper shows regression equations and their respective correlation coefficients for 107 soil-horizon samples of 21 soil profiles which belong to four soil classes: Red-Yellow Latosol dystrophic (RYLd); Red-Yellow Podzolic eutrophic (RYPE); Red-Yellow Podzolic dystrophic (RVPd) and "Terra Roxa Estruturada Similar" eutrophic (TRESe). The 1/3 atmosphere percentage (Y) was determined by pressure plate and the misture equivalent (x) by centrifuge, both of them using air dry soil samples < 2 mm diameter. The moisture equivalent values were almost same to those of 1/3 atmosphere percentage for the Podzolic and "Terra Roxa" soils. Using regression equations instead of direct values of "moisture equivalent" to represent 1/3 atmosphere percentage of the studied soils is suggested as a good option.