Another approach to quantifying soil processes and phenomena uses "in situ" methods that do not disrupt the soil as occurs when the soil is shaken or leached with an extracting soil solution. These methods usually use surface spectroscopic techniques, such as Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), Mossbauer spectroscopy, and X-ray spectroscopy. These approaches aim to obtain information on the chemical nature of the mineralogy and chemistry of particle and colloid surfaces, and how ions and molecules are associated with such surfaces by adsorption, complexation, and precipitation.