用稳态法确定中国土壤的硫沉降和氮沉降临界负荷

Estimating Critical Loads of Sulfur and Nitrogen for Chinese Soils by Steady State Method

在地理信息系统支持下 ,用稳态法确定了中国土壤的硫沉降临界负荷和氮沉降临界负荷 .中国硫沉降临界负荷最小 [<0 3g·(m2 ·a) - 1]的地区主要分布在东北的大兴安岭、小兴安岭和长白山 ,青藏高原南部雅鲁藏布江河谷以及云南西南部怒江和澜沧江流域 ,而酸沉降污染较为严重的富铝土区域 ,总体上都能够承受 0 8～ 3 2 g·(m2 ·a) - 1的酸沉降 .根据硫沉降临界负荷可以将中国大致划分为东南和西北 2部分 ,东南部大部分地区只能接受小于 3 2 g·(m2 ·a) - 1的硫沉降 ,而西北部普遍可以接受大于 3 2 g·(m2 ·a) - 1的硫沉降 ,其分界线基本上与4 0 0mm等降水量线重合 .与硫沉降临界负荷的分布不同 ,中国氮沉降临界负荷在总体上呈现自西向东逐渐增加的格局 .中国氮沉降临界负荷最低 [<1 0 g·(m2 ·a) - 1]的地区分布青藏高原西部和阿拉善高原 ,而氮沉降临界负荷最高 [>4 0 g·(m2 ·a) - 1]的地区则包括东北平原、华北平原。

Supported by the geographical information system (GIS), critical loads of sulfur and nitrogen of Chinese soils were estimated through the steady state method. Results showed that the lowest critical loads of sulfur [<0 3g·(m 2 ·a) -1 ] occurred on the Daxingan Mountain, Xiaoxingan Mountain and Changbai Mountain in northeast China, the valley of the Yaluzangbu River on the south of the Tibetan Plateau, and the catchments of the Nu River and the Lancang River in the southwest of Yunan province. However, the critical loads of southeast China, where acid deposition was very high, were intermediate and in the range of 0 8～3 2g·(m 2 ·a) -1 . According to the critical loads of sulfur, China might be divide into two parts approximately by the 400mm isohyet the northwest part could generally tolerate more than 3 2g·(m 2 a) -1 sulfur deposition, but the southeast one could not. Dislike the distribution of the critical loads of sulfur, the critical loads of nitrogen were low in the west China and high in the east. The lowest critical loads of nitrogen [<1 0g·(m 2 ·a) -1 ] occurred on the west of the Tibetan Plateau and on the Alashan Plateau, and the highest [>4 0g·(m 2 ·a) -1 ] on the Dongbei Plain, the Huabei Plain, the Changjiangzhongxiayou Plain, and the Sichuan Basin, etc.