Insert Fig. 4
The response of TN storage to specific LUCCs sampled at different depths exhibited similar pattern. The shallow sampling led to a higher loss efficiency of TN and TN storage loss efficiency gradually decreased with deeper sampling. TN loss efficiencys were 43.5%, 42.3%, 38.1%, 34.3% and 33.6%, respectively for the 0-20, 0-30, 0-40, 0-60 and 0-100 cm profiles. Land restoration increased the SOC and TN storages, and these gains occurred in these selected five sampling depths. Specifically, the gained SOC storage was 49.2% in the 0-20 cm soil layer, while the increased SOC was 10.5%, 19.7% and 20.9% respectively, in the 0-30, 0-40 and 0-60 cm profiles and the revered SOC lost was observed in the 0-100 cm profile. Thus, sampling depth significantly influenced the SOC and TN storages in response to LUCC.