A plate load test, standard penetration testing or local knowledge by an experienced geotechnical engineer, assuming the bearing level is near the surface. If subsurface, then standard penetration testing or cone penetrometer would be appropriate.
I agree with Ron. My other advice is to carry out boring or trial pitting to at least 3m depth for profiling and soil sampling, carry out classification tests such as sieve analysis, Atterberg limits. Soil profiling, Soil classification tests and insitu tests recommended by Ron, you can use those data to estimate conservatively an allowable bearing pressure at different depths. There are many standard or soil mechanics books which give allowable bearing pressure for every type of soil encountered on site. The one i like to use is British Standard Code of Practice for Foundations -BS8004: 1986).
I have been assigned to perform a series of Lefranc tests down a borehole. I have never come across such a term but assume it is either a constant or falling head test. any ideas on how to perform the test (standards?)