Phosphorus Extraction from Soil Constituents in Equilibrium and Kinetics Applying Bray P-1, Mehlich-1, and Olsen Solutions - Jamalam Lumbanraja; Department of Soil Science, Faculty of Agriculture, University of Lampung, Jl. Sumantri Brojonegoro No. 1, Bandarlampung 35145, Indonesia; Indonesia (UNIVERSITY OF LAMPUNG, 2017)