A soil aggregate composed Micro- of mineral and organic colony Quartz components, showing that localization of soil microbes Air Organt Very few microorganisms quartz G are found free in the soil Qu solution: most of them A occur as microcolonies Clay particle attached to the soil particlesA soil aggregate composed of mineral and organic components, showing that localization of soil microbes. Very few microorganisms are found free in the soil solution; most of them occur as microcolonies attached to the soil particles