Abstract
The research was conducted at the Purwodadi Botanical Gardens in three areas covered by the dominant vegetation Mahoni(Swietenia macrophylla), Jabon (Anthocephalus cadamba) and trembesi (Samanea saman) in January to May 2012. The purpose of thisstudy was to obtain a model infi ltration rate (cm/h) that was infl ued by physical and chemical properties of the soil that exist under thevegetation. Physical and chemicalparameters of soil chemical properties is observed macropore (%), organic matter (%), percentage ofthe fraction silt (%), sand(%), and clay(%), and bulk density (BD) (g/cm3). The six factors are thought to differ indirectly because of thespecifi cation and morphology of the dominant plant species shelter. Data infi ltration was collected by using the ring infi ltrometer, whilemacroporosity tested with metylen blue method, the properties of the other physical chemical factortested by laboratory of Departmentof Soil, Brawijaya University. The model derived from the analysis of the regression equation using SPSS software version 17.0. Thestudy produced three different models of infi ltration rate on each plot different, they were Y = - 15,8 + 17,3 X1 - 1,09 X2 + 1,53 X3 +0,001 X4 - 21,3 X6 (Mahoni's plot);Y = - 108 + 53,0 X1 - 0,68 X2 + 5,27 X3 - 0,470 X4 + 59,7 X6 (Jabon's plot); Y = - 20,1 + 17,4X1 - 1,06 X2 + 1,57 X3 + 0,082 X4 - 21,6 X6 (Trembesi's plot). Y= Infi ltration rate (cm/h), X1= macropore (%), X2= organic matter(%), percentage of the fraction silt (%) (X3), sand (%) (X4), and X6= bulk density (g/cm3). In the equation not found factor X5 (clayfraction) helped form a model because of multicollinearity analysis obtained by assuming that the clay fraction still contains a linearrelationship (correlated) with other variables.