INFLUENCE OF TEXTURE ON MOISTURE CHARACTERISTICS OF SOIL .V. RELATIONSHIPS BETWEEN PARTICLE-SIZE COMPOSITION AND MOISTURE CONTENTS AT UPPER AND LOWER LIMITS OF AVAILABLE-WATER

A quantitative assessment was made of the effect of the proportion of sand, silt, clay, and organic matter in twenty‐six soils on the moisture contents at the upper and lower limits of available‐water of the soils. Regression equations were obtained which enabled the moisture contents to be estimated on a weight or volume basis from mechanical analysis data using either International or American size grades. The accuracy of estimating the upper limit of available‐water from the various equations ranged from ±9 to 22 per cent: for the lower limit from ±8 to 16 per cent of the measured values. Mean values of the moisture contents at the upper and lower limits of available‐water for each textural class were calculated from the average particle‐size composition for each class and from the regressions obtained. Copyright © 1969, Wiley Blackwell. All rights reserved