陕西省不同生态区大气氮素干湿沉降的时空变异

Spatial-temporal variability of dry and wet deposition of atmospheric nitrogen in different ecological regions of Shaanxi

为研究陕西省不同生态区大气氮素干湿沉降的时空变化规律,于2009年11月至2010年10月对4个生态区5个监测点的干湿沉降输入量进行为期1a的观测。结果表明:监测期内,榆林、洛川、西安、杨凌和安康地区总N沉降量分别为4.7、11.9、25.8、31.9和19.2 kg/hm2,其中N湿沉降量分别为2.9、10.4、24.8、27.7和16.3 kg/hm2,占总沉降的62%—96%,N干沉降量分别为1.8、1.5、1.0、4.1和2.9 kg/hm2,占4%—38%,且湿沉降与降雨量之间呈正相关关系,干沉降与之相反;各地区NH+4-N沉降量分别为2.0、6.4、17.0、17.2和11.9 kg/hm2,占总沉降的44%—66%,NO-3-N沉降量分别为2.6、5.5、8.8、14.7和7.3 kg/hm2,占34%—56%,除榆林地区外,其他地区以NH+4-N沉降为主。

The objective of this experiment was to study the spatial-temporal variability of dry and wet deposition of atmospheric nitrogen in different ecological regions of Shaanxi Province. Measurements were made at five monitoring sites in four different ecological regions from November 2009 to October 2010. The amounts of total inorganic nitrogen （ TIN ） deposition were 4.7 kg/hm2 at Yulin, 11.9 kg/hm2 at Luochuan, 25.8 kg/hm2 at Xi＇an, 31.9 kg/hm2 at Yangling, and 19.2 kg/hm2 at Ankang. Wet deposition accounted for 62 to 96% of the TIN deposition, ranging from 2.9 kg/hm2 at Yulin, 10.4 kg/hm： at Luochuan, 24.8 kg/hm2 at Xi＇an, 27.7 kg/hmz at Yangling, and 16.3 kg/hm2 at Ankang. Dry deposition accounted for 4 to 38% of the TIN deposition, ranging from 1.8 kg/hm2 at Yulin, 1.5 kg/hm2 at Luochuan, 1.0 kg/hm2 at Xi＇an, 4.1 kg/hm2 at Yangling, and 2.9 kg/hm2 at Ankang. Wet deposition and rainfall were positively correlated, whereas dry deposition and rainfall were negatively correlated. Ammonium nitrogen （ NH4-N） deposition amounts were 2.0 kg/hm2 at Yulin, 6.4 kg/hm2 at Luochuan, 17.0 kg/hm2 at Xi＇an, 17.2 kg/hm2 at Yangling, and 11.0 kg/hm/ at Ankang. These amounts accounted for 44 to 66% of the TIN deposition. Nitrate nitrogen （NO3-N） amounts were 2.6 kg/hm2 at Yulin, 5.5 kg/hm2 at Luochuan, 8.8 kg/hm2 at Xi＇an, 14.7 kg/hm2 at Yangling, and 7.3 kg/hm2 at Ankang. These amounts made up34 to 56% of the TIN deposition. Nitrogen deposition is mainly in the form of NH4-N in all regions except Yulin.