Browsing by Autor "Rong Yang"

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Decadal changes and ecological risk assessment of trace and heavy metal elements in soils of a desert oasis, Linze County, China
(CSIRO Publishing, 2019) Rong Yang; Zeyu Du; Junqia Kong
This study assesses decadal changes (2005–2015) in the trace and heavy metal element contents of soils from four land use types at a desert oasis and also determines associated ecological and health risks. Concentrations of boron, molybdenum, manganese, zinc, copper, cadmium, lead, and mercury increased significantly over the decade. Farmland ecosystems had higher concentrations of soil trace and heavy metal elements than natural ecosystems, but intercropping with alfalfa tended to reduce concentrations. The environmental pollution assessment indicated that soils were moderately affected by human activities, particularly in farmland ecosystems. The potential degree of ecological risk from all elements was moderate, and in relation to land use this risk decreased in the following order: long-term cultivated farmland &gt; newly reclaimed farmlands with monoculture &gt; newly reclaimed farmlands with intercropping &gt; natural desert grassland. Eight soil heavy metals posed potential non-carcinogenic risks, and dermal contact was the major exposure pathway; however, the carcinogenic risk level from soil was acceptable. These results suggest that agricultural activities increased the concentrations of certain soil trace and heavy metal elements and that adopting appropriate farmland management, such as intercropping with alfalfa, limited this increasing trend.
Soil texture controls vegetation biomass and organic carbon storage in arid desert grassland in the middle of Hexi Corridor region in Northwest China
(CSIRO Publishing, 2015) Yongzhong Su; Jiuqiang Wang; Rong Yang; Xiao Yang; Guiping Fan
Soil texture plays an important role in controlling vegetation production and soil organic carbon (SOC) concentration in arid desert grassland ecosystems. However, little is known about the occurrence and extent of these textural effects in the arid desert grasslands of Northwest China. This study used 160 soil profiles taken from 32 desert grassland sites in similar topographical units (alluvial–diluvial fans) in the middle of Hexi Corridor region of Northwest China to investigate vegetation biomass, SOC storage, and soil texture of seven layers in the top 100 cm of soil. The mean aboveground biomass, below-ground biomass, and total biomass in arid desert grassland were 155.3, 95.3, and 256.3 g m–2, respectively. More than 95% of the below-ground biomass was distributed in the top 30 cm of soil. Spatially, vegetation biomass was positively related to soil clay content and silt + clay content. The mean SOC density in the top 100 cm was 2.94 kg m–2 and ~46.8% of the storage was concentrated in the top 30 cm. SOC concentrations and stocks were positively and significantly related to clay content and silt + clay content in the seven soil layers sampled from the top 100 cm. The soil silt + clay content explained 42–79% of the variation in SOC stocks in the different soil depths. In conclusion, soil texture appears to be an important control on vegetation productivity and SOC capacity in arid Hexi Corridor desert grassland soils.