The effect of afforestation on inorganic carbon in soils of arid and
semi-arid lands of northwest China
Abstract
Alxa is a region with severe land desertification and extreme ecological
fragility in China. The plantation in the area has effectively curbed
the desertification of the local land. However, Studies on soil
inorganic carbon(SIC)dynamics after sandy land afforestation are still
relatively few. Understanding SIC profiles’ distribution and stock
changes after afforestation is essential for assessing regional,
continental, and global soil carbon sink potential. Using 5, 11, 22, and
46 years of Haloxylon ammodendron (H. ammodendron) plantations and
control sands (MS) in the Alxa region, we studied the variation
characteristics of SIC with increasing stand age from 0 to 300 cm.
Within the 0-300 cm soil layer, SIC storage increased significantly
after afforestation, with 46yrs increasing by 6.52 kg m-2 compared to
MS. SIC sequestration rate (CSR) decreased with increasing stand age, in
the order of 5yrs(0.054 kg m-2 yr-1)>11yrs(0.025 kg m-2
yr-1)>22yrs(0.016 kg m-2 yr-1)>46yrs(0.009 kg m-2 yr-1). The
100~300 cm SIC storage accounts for over 60% of the SIC
pool. Soil carbon pool estimation will be largely underestimated if only
the shallow SIC is considered.