Evaluation of the Least Limiting Water Range for a Typic Argiudoll under Different Intensities of Agricultural Use

Abstract

The least limiting water range (LLWR) has been proposed as an indicator of physical soil quality that integrates aeration, penetration resistance, and soil water content effects on plant growth in a single parameter. The objective of this study was to evaluate the LLWR along with other soil physical properties under different rotation and fertilization treatments. The research was conducted on a typic Argiudoll, in Colonia, Uruguay, in a long-term crop-pasture rotation experiment started in 1963. The treatments evaluated were: a) continuous agriculture without fertilization (ACs / Fert), b) fertilized continuous agriculture (AC), c) crop-pasture rotations with 50 % of the time under crops (50 % Cult), and d) crop-pasture rotations with 33 % of time under crops (33 % Cult). The LLWR decreased with increasing cropping intensities, ranging between 0,08 and 0,02 cm3 cm-3 for treatments 33 % Cult and ACs / Fert, respectively. Thus, the LLWR allowed assessing a decline in soil physical quality. The analysis of the limits of the LLWR allowed understanding the possible physical restrictions that would be affecting plant growth, showing that aeration and resistance to penetration become increasingly limiting with higher cropping intensities.