用SMB法确定中国土壤的营养氮沉降临界负荷

Evaluating critical loads of nutrient nitrogen on soils in China using the SMB method

为了对中国的氮沉降控制提供依据,确定了土壤的氮矿化速率、反硝化速率和临界氮淋溶速率以及植被对氮的吸收速率等参数,运用简单质量平衡法(SMB)对营养氮沉降临界负荷进行了计算和区划。结果表明:中国土壤营养氮沉降临界负荷的分布总体上呈现自西向东逐渐增加的格局,青藏高原和内蒙西部、新疆东部等地区(温带、亚热带高寒草原、温带高寒矮半灌木荒漠和温带矮半灌木荒漠)临界负荷小于0.5kmol.hm-2.a-1,而超过国土面积2/3的大部分地区则大于1.0kmol.hm-2.a-1。

The critical loads of nutrient nitrogen on soils were calculated and mapped using a simple mass balance (SMB) method to predict nitrogen deposition potential in China. The analysis considered important parameters such as nitrogen imbalance, denitrification, critical nitrogen leaching in soils, and nitrogen uptake by vegetation. The results showed that the lowest critical loads (<0.5 kmol·hm-2·a-1) occurred on the western side of the Tibetan Plateau and the Inner Mongolia Plateau, and in the eastern part of the Xinjiang Uigur Autonomous Region. However, most parts of China (over 2/3 of the land) were not sensitive to nitrogen deposition, with relatively high critical loads (>1.0 kmol·hm-2·a-1). In general, the critical nitrogen loads are lower in the west and higher in the east.