模拟氮沉降对华西雨屏区苦竹林凋落物养分输入量的早期影响

2007年11月至2010年12月对华西雨屏区苦竹人工林进行了模拟氮(N)沉降试验,氮沉降水平分别为：对照(0 g N.m_–2.a_–1),低氮(5 g N.m_–2.a_–1),中氮(15 g N.m_–2.a_–1),高氮(30 g N.m_–2.a_–1)。在氮沉降2 a后,于2010年1月开始收集各样方的凋落物样品,连续收集12个月,测定凋落物量和养分输入量。结果表明：氮沉降显著增加了凋落物量；同时显著增加了凋落叶中的N、P、K、Ca、Mg元素含量和这几种养分元素的年输入量。本研究表明模拟氮沉降处理增加了凋落物对土壤养分的输入量,这对于维持苦竹林地肥力与保持苦竹林分的长期生长力具有重要的作用。

Early effects of simulated nitrogen deposition on annual nutrient input from litterfall in a Pleioblastus amarus plantation in Rainy Area of West China

The human activities such as combustion of fossil fuels and intensive agriculture, have changed the nitrogen(N) cycle considerably, and have significantly increased the formation and deposition of the reactive N. The increasing deposition of N has exerted much effect on activities of forest ecosystem, such as the alteration of litter production and nutrient concentration of litterfall. In the forest ecosystem, litterfall as the source of soil nutrient and energy plays an important role not only in conserving soil and water and improving the structure and physical-chemical properties of soil, but also in maintaining soil fertility, which links the nutrient pool of vegetation and the soil nutrient pool. The annual nutrient input from litterfall is the product of annual litter production and the nutrient concentration of litterfall, which is the major source of soil fertility. Therefore, exploring the influence of nitrogen deposition on totally annual nutrient input from litterfall has the vital significance, while the related report is rare.