Estimation of percent aluminum saturation from soil chemical data

Abstract

Numerous studies since the early 1970's have shown that percent aluminum (Al) saturation of the soil ion exchange complex is a useful index for predicting the effects of Al toxicity on crop yield and root growth. However, direct measurements of percent Al saturation are unavailable for many acid soils, especially for those sampled prior to the early 1970's. This paper presents simple multiple regression equations based on texture and frequently measured chemical properties for 446 horizons of 102 soil pedons of Alfisols, Inceptisols, Oxisols, Spodosols, and Ultisols. The regression equations account for up to 91% of the Variation in percent Al saturation for the data set used to generate the equations. For an independent data set of 45 horizons (9 from Alfisols, 10 from Inceptisols, 13 from Oxisols, 5 from Spodosols, and 8 from Ultisols) the simple correlation coefficient between actual and estimated percent Al saturation was 95%.

Key words:

• Aluminum toxicity
• base saturation
• cation exchange capacity

Notes

Published in cooperation with the Texas Agricultural Experiment Station.

Plant Physiologist, ARS, Grassland, Soil and Water Research Laboratory, P. O. Box 748, Temple, TX 76503.