The acid soils used in this study displayed contrasting soil properties, which reflected differences in
Jenny’s state factors of soil formation and P input levels. Strongly weathered soils derived from granitic
materials exhibited the lowest level of nutrient availability, lowest soil pH and highest level of exchangeable
Al. The statistical evaluation of causal factors of different maize growth along a P availability range
indicates that the low P use efficiency and low potential biomass production in the acid soils are associated
with low levels of Ca and other basic cations and/or Al toxicity. Multivariate statistical analysis
through PCA produced similar results through the identification of 4 components that reflected 4 key
soil qualities that were labeled nutrient deficiency, soil organic matter, soil texture, and HCl-P. The
nutrient deficiency component integrated most chemical variables that significantly influenced maize
growth and revealed as the only soil quality statistically correlated to biomass production function.
Organic matter and soil texture despite their key role in several soil and ecosystem functions showed
no direct effect on biomass production. The last component that reflected HCl-P indicated that this
P pool was less bioavailable. In summary, this study indicates that efficient management of acid soils
needs to alleviate their P deficiency, low levels of basic cations, and aluminum toxicity.