Aqua regia will not give a total analysis for metals in soils.
A mixed acid (usually four-acid: HF+HNO3+HCl+HClO4) digest gives as close to a total analysis as possible with a digestion procedure, as it will dissolve even recalcitrant silicates, etc. (but not necessarily very resistant minerals like chromite).
An alternative is fusion with a lithium metaborate / lithium tetraborate flux, followed by dissolution of the fused material in dilute (~1M) HCl or HNO3, with analytical finish by ICP-OES or ICP-MS. In my lab we have achieved similar results to XRF (X-ray fluorescence) using this method with an ICP-OES finish.
Depending on the lower limits of detection you require, XRF could also be an alternative.
For methods descriptions look at http://pubs.usgs.gov/of/2002/ofr-02-0223/ on the USGS website
for total you need microwave digested HF to dissolve the Phylosilicates
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