Soils
Two acid soil types in the study area were selected. The Ultisol (Leilehua
series) was a very fine, ferruginous, isothermic, Ustic Kanhaplohumult and the
Oxisol (Wahiawa series) was a very fine, kaolinitic, isohyperthermic, Rhodic
Haplustox. Selected chemical characteristics are listed in Table 1. Substantial
amounts of extractable Al and high Al saturation indicated that Al toxicity
might be a problem in the Ultisol. Hue et al. (1998) reported large amounts
of total (17 g kg−1) and extractable Mn (>500 mg kg−1) in the Oxisol, which
indicated that Mn toxicity might be a problem in that soil.