应用15N稀释技术定量华北平原大气氮沉降的输入总量（英文）

本文采用定量氮沉降总量的ITNI（Integrated Total Nitrogen Input）系统,利用¹⁵N稀释原理和生物监测技术,定量研究了华北平原大气氮沉降的农田输入总量及其在推荐施肥中的作用。结果表明,以玉米和小麦为指示植物,监测到在玉米-小麦轮作体系中整个华北平原大气氮沉降的输入总量高达80-90 kgN ha^-1yr^-1,对玉米和小麦植物有效性的沉降氮总量约为50 kgN ha^-1yr^-1。以黑麦草为指示植物,监测到华北平原大气氮沉降的输入总量约为100 kgN ha^-1yr^-1,对其植物有效性的沉降氮约为76 kgN ha^-1yr^-1,占总沉降氮的77%。由于华北平原小麦季扬尘较多,因此干沉降可能是该时期大气氮沉降输入总量的主要贡献。

Determining Total N Deposition Using 15N Dilution Technique in the North China Plain

Atmospheric N deposition has become an environmental concern in the North China Plain (NCP), because of the large anthropogenic reactive N emissions in this region since the 1990s. A manually integrated total N input (ITNI) method was developed using 15N-labelled monitor plants grown in pots to obtain accurate measures of total N deposition to the agroecosystems in the NCP and to improve N-fertilizer recommendations. In the NCP, total airborne N input into the maize-wheat rotation system is 80-90 kg N ha-1 yr-1, and the plant available N from deposition for maize and wheat plants is c. 50 kg N ha-1 yr-1. While total airborne N input measures at almost 100 kg N ha-1 yr-1 when ryegrass is used as the monitoring plant the plant available N from deposition for ryegrass is c. 76 kg N ha-1 yr-1, accounting for 77% of the total N deposition. Dry deposition is likely to be the major contributor to the total N deposition during the wheat growing season in the dry and dusty NCP. In order to obtain reliable N deposition results,especially when the plant density in small area pots (0.57 m2) is different from the density in the field, we found that a correction factor (0.54 in this study) had to be used for maize to rectify values obtained from pot area.