Carbon dioxide fixed in plant biomass through afforestation inevitably impacts the quality, quantity and spatial and temporal dynamics of soil organic carbon (SOC) pools. Thus, understanding the dynamics of SOC pools following afforestation is critical for the development of terrestrial forest conservation and management strategies. 

However, no consensus has yet been reached regarding the effects of afforestation on SOC sequestration, and quite few studies have explored the effects of afforestation on sequestration patterns of total and labile SOC fractions. 

Recently, a research group from the Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences, together with colleagues from Gansu Desert Control Research Institute, examined the effects of Caragana microphylla plantations with different ages on organic carbon sequestration in total and labile soil organic carbon fractions in the Horqin Sandy Land. 

Scientists analyzed the samples from soil depths of 0-5 and 5-15 cm under two shrub-related scenarios, and evaluate the amounts of organic carbon in terms of total SOC and labile SOC fractions in different-aged C. microphylla plantations in the Horqin Sandy land, and obtain a further understanding on which SOC fraction responds to C. microphylla plantations more sensitively. 

The results showed that the concentrations and storages of total SOC at soil depths of 0-5 and 5-15 cm were higher in 12- and 25-year-old C. microphylla plantations than in moving sand dunes, with the highest value observed under shrubs in 25-year-old C. microphylla plantation. 

This study demonstrates that the total and labile SOC fractions show significant increases in the first 12 years after afforestation with C. microphylla shrubs on moving sand dunes in the Horqin Sandy Land. 

It can be concluded that the establishment of C. microphylla in the Horqin Sandy Land may be a good mitigation strategy for SOC sequestration in the surface soils. 

The results of this study are important for providing scientific reference on the effects of C. microphylla plantations on SOC sequestration in the Horqin Sandy Land and also for other similar regions. 

The research results have been published in the Journal of Arid Land in an article entitled "Effects of Caragana microphylla plantations on organic carbon sequestration in total and labile soil organic carbon fractions in the Horqin Sandy Land, northern China". 

Horqin Sandy Land (Image by NIEER)