A Study on Carbon Sink of Reforestation Under Different 'Grain for Green' Models in the Southern Ningxia Province of Loess Hilly Region

摘要

Based on biomass collected from field surveys and carbon contents determined in laboratory, carbon storage of different reforestation under different models for conversion of cropland to forestland or pasture and its distribution characteristics were examined. The results showed as follow: the carbon stock of the different reforestation models is L. gmelini (106.12 t-hm~(-2)) > P. sibirica (85.08 t-hm~(-2)) > P. davidiana (77.78 t-hm~(-2)) > Hippophae rhamnoides (63.29 t-hm~(-2)) > Caragana korshinskii (52.82 t-hm~(-2)). Compared to that of the sloping cropland (59.55 thm~(-2)), carbon densities of P. sibirica and L gmelini ecosystems increased by 42.90% and 78.20%, respectively; for the Hippophae rhamnoides and P. davidiana ecosystems, the number increased by 6.28% and 30.61%; carbon content in soil layer between 0-100cm reduced significantly with the depth, the distribution pattern of carbon sequestration was in the order of soil layer > vegetation layer.