Soil organic carbon and total nitrogen storage under different land uses in the Naiman Banner, a semiarid degraded region of northern China

Li, Y., Han, J., Wang, S., Brandle, J., Lian, J., Luo, Y. and Zhang, F. 2014. Soil organic carbon and total nitrogen storage under different land uses in the Naiman Banner, a semiarid degraded region of northern China. Can. J. Soil Sci. 94: 9–20. Accurate investigation of soil organic carbon (SOC) and total nitrogen (TN) storage at a regional level is important for detecting changes in the C and N sequestration and emission potentials induced by land-use and cover type changes. In a degraded semiarid region of northern China's Horqin Sandy Land, we selected 208 locations and calculated SOC and TN storage to a depth of 100 cm for the main land-use and cover types. The productive cropland on former grassland had the highest level of SOC and TN storage (6613 g C m⁻² and 709 g N m⁻²). The corresponding storage values were 3758 g C m⁻² and 402 g N m⁻² in degraded grassland, 3449 g C m⁻² and 373 g N m⁻² in afforested dunes, 2674 g C m⁻² and 320 g N m⁻² in unproductive cropland on former dunes, and 1109 g C m⁻² and 129 g N m⁻² in sand dunes (from mobile to fixed). The average soil bulk density was highest in sand dunes, with a value of 1.59 g cm⁻³, and lowest in productive cropland on former grassland, with a value of 1.39 g cm⁻³. The conversion of severely degraded sandy land into other land-use and cover types therefore has considerable potential to partially offset the SOC and TN loss during the past century that has resulted from desertification in the Horqin Sandy Land.