Detritus or animals and plant parts are decomposed by microbes like bacteria and fungi. The rate of these decomposes is affected by abiotic factors like temperature, moisture, $\mathrm{pH}$ of soil and light. Soil $\mathrm{pH}$ affects composition of acidic and alkaline microbes. Anaerobiosis and acrobiosis occure in absence of oxygen and pressure of oxygen respectively.

The substance is completely decomposed in presence of oxygen while anaerobiosis and aerobiosis processes occure in absence of oxygen and presence of oxygen. Similarly microbes do not possess growth in best way at high temperature but either at high or low temperature tallerent microbes possess growth.