中文摘要：

采用二次正交回归旋转设计，研究模拟氮硫沉降下建阳市的邓恩桉幼林凋落物C、N含量动态变化。经过1a的监测和分析发现，凋落物分解过程中，C、N含量均呈双峰变化模式，各处理间呈显著差异，C含量在初始值（44.76%）附近上下波动，N含量整体随时间呈增长趋势。Na2SO4为130－192 kg·hm-2·a-1， CO（NH2）2为203－300 kg·hm-2·a-1，氮硫两因子沉降量增加有利于C、N含量的增加。Na2SO4为192 kg·hm-2·a-1，CO（NH2）2为300 kg·hm-2·a-1，C含量最大；Na2SO4为192 kg·hm-2·a-1，CO（NH2）2为256 kg·hm-2·a-1，N含量最大。研究为邓恩桉人工林可持续经营提供基础数据和理论参考。

英文摘要：

The dynamic changes of carbon and nitrogen contents of Dunn eucalyptus plantation litterfall under nitrogen and sulfur deposition were studied by the quadratic rotatio-northogonal combination design in Jianyang. Based on one year of litterbag collection and analyses, carbon and nitrogen contents showed two peaks, showing very significant diff erence between treatments. Carbon contents fluctusted around initial value （44.76%）, and nitrogen contents preasented a n increasing trend by time. When Na2SO4 content was between 130 kg·hm-2·a-1 and 192 kg·hm-2·a-1, CO（NH2）2 content was between 203 kg·hm-2·a-1 and 300 kg·hm-2·a-1, carbon contents increased by adding the contents of Na2SO4 and CO （NH2）2. Besides, carbon contents reached a maximum on condition of Na2SO4 content in 192 kg·hm-2·a-1 and CO（NH2）2 content in 300 kg·hm-2·a-1,nitrogen contents reached a maximum on condition of Na2SO4 content in 192 kg·hm-2·a-1 and CO（NH2）2 content in 256 kg·hm-2·a-1. Therefore, the results can provide basic data and theoretical reference for plan tation and sustainable management of Eucalyptus Dunnii Maiden.