EDXRF measurements with synchrotron photons were performed for K X-rays of potassium, calcium and iron in mint plants and soils from a pot experiment with nutrient fertilization treatments keeping all other environment factors; soil, light, temperature and watering same. X-ray peak energies with precision 10-4 of channel width were evaluated using SOLVER fitting, a powerful program included in Microsoft Excel for Windows. Results showed energy shifts with fertilizations that may be because of change in the structure and chemical environment of detecting elements in both plants and soils. Potassium and calcium fertilizations affect potassium peak energy more than calcium and iron peak energies in mint saplings and the soils.
