Soil carbon and nitrogen storage of different land use types in northwestern Shanxi Loess Plateau.

The soil organic carbon (SOC) and total nitrogen (TN) storage under five different land use patterns, i. e. , poplar and Caragana microphylla plantation, C. microphylla artificial shrubland, poplar plantation, bare land and cropland were studied in the hilly Loess Plateau of north-western Shanxi. The results showed that the contents, densities and storage of SOC and TN varied remarkably under the different land-use patterns. Soil carbon and nitrogen contents and storage in the 0^-20 cm soil layer were significantly higher in the 20-40 cm and 40-60 cm soil layers under each of the five land use patterns. In the same soil layer, the contents and densities of SOC and TN under the five land use patterns were in the order of poplar and C. microphylla plantation > C. microphylla artificial shrubland > poplar plantation > bare land > cropland. The SOC storage in the 0-60 cm soil layer was in the order of poplar and C. microphylla plantation (30. 09 t.hm^-2) > C. microphylla artificial shrubland (24. 78 t.hm^-2 ) > poplar plantation (24. 14 t.hm^-2 ) > bare land (22. 06 t.hm^-2) > cropland (17. 59 t.hm^-2). Soil TN storage had the same trend as SOC storage, and TN storage in the 0-60 cm soil layer was the highest (4. 94 t.hm^-2 ) in poplar and Caragana microphylla plantation, followed by C. microphylla artificial shrubland (3. 53 t.hm^-2), poplar plantation (3. 51 t.hm^-2), bare land (3. 40 t.hm^-2 ), and cropland (2. 71 t.hm^-2 ). Poplar and C. microphylla plantation and C. microphylla artificial shrubland were the good land use patterns in the process of vegetation construction and ecological restoration in the hilly Loess Plateau of northwestern Shanxi. [ABSTRACT FROM AUTHOR]