These are very inert chemical compounds. Unlike Kansas or other typical mainland sites, Hawaii soils are not usually full of reactive minerals like calcium carbonates from sedimentary rocks such as limestones. Our water is soft, not hard and mineral laden like in Kansas. So you would expect our glassy soils to be lousy conductivity vs. nice wheat fields in Oklahoma. But wait, ocean wave action is constantly generating salt spray that evaporates and makes tiny specs of salt in our trade winds.
Salt is a major problem with Hawaii soils.
In fact, in regions that get trade winds bringing in ocean salt and because of local geography are in a rain shadow and dry, salt can build up to near lethal levels. The Romans used to sow fields with salt to destroy the productivity of farm land and make conquered peoples dependent on them for food until rain could leach out the salt and restore the land's usefulness. Such saline soil areas can accumulate conductivities over 10 decisiemen per meter. At that sea salt level not much can grow. Many plants can be done in by 3 decisiemen per meter if all that conductivity is due to sodium chloride from sea salt.