digraph soil {
        size="8,8";
        node [fontsize=12, color = lightblue2, style = filled];
       
        "solar radiation budget" [color = yellow];
        "Cs log(As)" [color = yellow];
        "landscape position" [color = yellow];
        "aspect" [color = yellow];
        "geology" [color = yellow];
        "VEG" [color = yellow];
        "landscape / landform age" [color = red];
       
        subgraph cluster0 {
                "surrounding terrain";
                "precip";
                "landscape position";
                "aspect";
                "local weather";
                "VEG";
                "solar radiation budget";
                "Cs log(As)";
                "soil moisture status";
                "xy water routing";
                "energy flux";
                "erosional / depositional surface";
        }

        subgraph cluster1 {
                "geology";
                "parent material";
                "soil texture";
                "infiltration rate";
                "leaching";
                "weathering rate";
                "landscape / landform age";
                "vertical soil development";
                "soil properties";
                "taxonomy";
        }
       
        "erosional / depositional surface" -> "weathering rate" ;
        "parent material" -> "landscape / landform age" -> "soil texture";
        "parent material" -> "weathering rate";
        "geology" -> "parent material" -> "soil texture";
       
        "landscape position" -> "xy water routing";
        "local weather" -> "solar radiation budget";
        "solar radiation budget" -> "soil moisture status" -> "VEG";
        "landscape position" -> "aspect" -> "solar radiation budget";
        "landscape position" -> "Cs log(As)" -> "erosional / depositional surface";
        "surrounding terrain" -> "solar radiation budget";
        "surrounding terrain" -> "landscape position";
        "surrounding terrain" -> "precip" -> "Cs log(As)";
        "Cs log(As)" -> "xy water routing";
        "xy water routing" -> "soil moisture status";
        "xy water routing" -> "energy flux" [style = dotted];
        "VEG" -> "energy flux";
        "soil moisture status" -> "energy flux" [style = dotted];
        "energy flux" -> "weathering rate";
        "soil texture" -> "infiltration rate";
        "soil texture" -> "weathering rate";
        "infiltration rate" -> "weathering rate";
        "infiltration rate" -> "leaching" -> "vertical soil development";

        "weathering rate" -> "vertical soil development";
        "landscape / landform age" -> "vertical soil development" [style = dotted];
        "vertical soil development" -> "soil properties";
        "vertical soil development" -> "taxonomy" [style = dotted];
        "soil properties" -> "taxonomy";
}