 Plant derived soil carbon is a continuum, ranging from living biomass to humus, and it decays in different stages, ranging from months (decomposable plant material; DPM) to hundreds of years (humus).The rate of decay depends on many factors, for instance plant species, soil, temperature and humidity, but as long as fresh new carbon is input, a certain amount of carbon stays in the ground—in fact Poeplau et al.did not find any "[…] indication of decreasing SOC [soil organic carbon ] accumulation with age of the plantation indicating no SOC saturation within 15–20 years."