Genotypic Differences in Cotton Root Penetration of a Compacted Subsoil Layer

Abstract

Roots able to penetrate through compacted subsoil might result in better use of soil water. This study was conducted to determine whether roots of cotton (Gossypium hirsutum L.) genotypes differ in ability to penetrate through compacted soil and, if so, to develop a system for early identification of superior rooting. Sixteen genotypes were compared without irrigation in Norfolk loamy sand (fine‐loamy siliceous, thermic Typic Kandiudult) overlying a compacted subsoil layer near Florence, SC. Some remained turgid, while others wilted. Roots of the turgid genotypes penetrated the compacted layer, whereas few roots of the wilted genotypes did. One line that remained turgid and one that wilted in the field were then studied over artificially compacted soil cores. Roots of the turgid (but not the wilted) genotype penetrated bulk densities of 1.4 g cm−3. Artificially compacted cores can provide a tool to evaluate genotypes for root penetration as an early part of cultivar development for sandy soils that overlie compacted subsoil.