Remaining Phosphorus Estimate Through Multiple Regression Analysis1

ABSTRACTThe remaining phosphorus (Prem), P concentration that remains in solution after shaking soil with 0.01 mol L−1 CaCl2 containing 60 μg mL−1 P, is a very useful index for studies related to the chemistry of variable charge soils. Although the Prem determination is a simple procedure, the possibility of estimating accurate values of this index from easily and/or routinely determined soil properties can be very useful for practical purposes. The present research evaluated the Prem estimation through multiple regression analysis in which routinely determined soil chemical data, soil clay content and soil pH measured in 1 mol L−1 NaF (pHnaf) figured as Prem predictor variables. The Prem can be estimated with acceptable accuracy using the above-mentioned approach, and pHNaF not only substitutes for clay content as a predictor variable but also confers more accuracy to the Prem estimates.