Mapping critical loads of sulfur and nitrogen for soils in Zhanjiang

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Mapping critical loads of sulfur and nitrogen for soils in Zhanjiang

Journal Title: Science Paper Online - Year 2007, Vol 2, Issue 7

Abstract

Supported by the geographical information system (GIS), critical loads of sulfur and nitrogen of soils in Zhanjiang area, Guangdong province were estimated through the steady state method. According to the critical loads of sulfur, the area can be divided into three parts, with high values (>5.0 keqhm-2a-1) in the northern and southern ones where coniferous/ broadleaf-conifer-mixed forest and cultivated vegetation are distributed respectively, and low values (<1.0 keqhm-2a-1) in the middle one where broadleaf forest is dominated. The distribution pattern of critical loads of sulfur coincides well with that of vegetation, because the spatial variation of the uptake rates of base cation by vegetation are much more significant than that of the weathering rates of soils in the area. In comparison with the critical loads of sulfur, the critical loads of nitrogen are commonly high (>5.0 keqhm-2a-1) as a results of abundant vegetation and thus high uptake rates of nitrogen by vegetation. It is estimated that critical loads have been exceeded by sulfur deposition or nitrogen deposition in more than half of the area, most of which occurs in broadleaf forest in the middle part with only sulfur exceedance. In addition, the nitrogen exceedance occurs mainly in coniferous/broadleaf-conifer-mixed forest in the northern part.

Authors and Affiliations

Lei Duan, Xianbo Xian, Pixue Li

Keywords

critical loads Soil Sulfur Nitrogen steady state method Zhanjiang

EP ID EP102237
DOI -
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