Naime, R. and Fiori, A.P. 2004. Influence of some variable environmental and geological in the behavior of ratio qc/N in the soils of Porto Alegre. Semina: Ciências Exatas e Tecnológicas. 22, 1 (Jul. 2004), 51–61. DOI:https://doi.org/10.5433/1679-0375.2001v22n1p51.