How to measure capacitance of soil without being affected by resistance?
The magazine RF Design provided circuit for inductance meter, many years ago.
Ran at 100,000Hz and used NE602 double-balanced mixer that cancelled both the RF input and the LO input, leaving only the differential sum+difference energy as the output.

Given real inductors have losses (real) in addition to the energy-storage (reactive) component, that meter used a precise quadrature source of current, imposed across Kelvin force-sense terminal pairs.

I redesigned the meter to run at 10MHz, with full scale of 1,000 nanoHenries, for measuring very small inductors and some PCB parasitics. The terminals were 1cm squares of PCB material, with "force" on one edge, "sense" on opposite edge, and the "test point" the intervening orthogonal edge.

For a capacitance meter, take the opposing approach: there is no DC path needed, thus a VOLTAGE is needed. You must extract the real and the quadrature components; The "capacitor" will induce 90 degrees; the losses will be inphase.