4.2 PhytOC long-term sequestration potential
Many previous studies have assessed the potential of PhytOC
sequestration in various ecosystems, such as forest, grassland, wetland
and agriculture ecosystems (Parr et al., 2010; Parr et al., 2009; Li et
al., 2013b; Zuo et al., 2011). But most of these assessment are based on
the PhytOC production in plant aboveground biomass, ignoring that in
belowground biomass. A recent study (Chen et al., 2018) reports that the
belowground biomass in a bamboo forest accounts for 39.41% of the total
plant biomass.. Another recent study (Zhang et al., 2019) shows that the
litter layer in bamboo forest plays a important role as phytOC storage.
In native steppes, plant aboveground biomass turns to litter in current
year, while the belowground biomass is huge and accumulated over
multiple years (Chai, et al., 2014; Dai, et al., 2012; Hou, et al.,
2014). Qi et al. (2016) shows that phytOC production from the
belowground part is much greater than that from the aboveground parts
for the typical steppe. The results of the present study confirms the
previous findings with more data from three steppe types along a
precitation gradient, and indicate the necessity to involve the
belowground part in the assessment of PhytOC production and
sequestration potential.