pebblepedpedalfarpedestal erosionpediplainpedocalpedogenicpedonpeimitive waterpelean cloudpellicular erosionpellicular waterpendular waterpeneplainpenetrabilitypenstockpercent of normal indexperched aquiferpercolationpercolation passpercolation testpercusive actionpercussionpergrlicperimeter of watershedperiodperiod averageperiod of operationperiodicperiodic splineperipheral weirperlitepermafrostpermanent pasturepermanent waterpermanent wilting percentagepermanetly absorbed waterpermeabilitypermeability coefficientpermeable rockpermeameterpermissible soil losspermissible tractive forcepermissible unit tractive forcepermissible velocitypernnial streampetrifying wellpetrocalcice horizonpetrogypsic horizonpfactor