Lin et al. (1988) used a mesh bag technique to examine
the effect of phosphogypsum versus lime on
alleviating poor root growth in a Spodosol Bh
horizon.
Soil in mesh bags was amended with either lime or
phosphogypsum, and the bags were implanted around
mature orange trees and sampled for periods up to 139
days. The Bh
horizon amended with lime had significantly
higher root densities than control soils, but root
densities in phosphogypsum-amended soil were not
significantly different than those of controls. In this
study, phosphogypsum did not decrease exchangeable
Al compared to control soils.