华西雨屏区不同人工植被类型下土壤氮库及其有效性

为了解华西雨屏区人工植被类型对土壤氮库及其有效性的影响，选取华西雨屏区7种典型人工植被类型：橘树（Glycosmis cochinchinensi5）迹地、橘树林地、巨桉（Eucalyptus grandis）林地、玉米（Zeamays）地、香樟（Cinnamonum camphora）林地、柚子（Citrus mnxima）林地和桃树（Pmnnus persica）林地，于2010年7月分别采集土壤根层与根下层原状土样，分析其氮库及有效性。结果表明，华西雨屏区几种典型人工植被类型均表现出较大的氮库特征，但不同人工植被类型间具有较大的差异。相对于其他植被类型，玉米地根层和根下层土壤氮库均相对较小，而橘树、柚子和桃树林地根层土壤氮库相对较大，巨桉、香樟和桃树林地根下层土壤氮库相对较大。然而，玉米地具有较高的根层土壤铵态氮和硝态氮含量，但巨桉林地具有较低的根下层土壤铵态氮和硝态氮含量。这些结果为区域氮素合理利用、土地利用结构调整以及生态环境建设提供了一定理论依据。

Effects of Planted Vegetations on Soil Nitrogen Pool in Rainy Area of West China

To understand the effects of planted vegetations on soil N pool and its availability in Rainy Area of West China, 7 representative vegetations were selected including orange cutver plantation, orange plantation, eucalyptus plantation, corn farmland, camphor plantation, grapefruit plantation and peach plantation. Soils were sampled in the root layer and under-root layer in July,2010. Soil N content and available N （ NH4-N and NO3 -N ） content were analyzed, and soil N pool was calculated. The results indicated that there were significant effects of planted vegetation on soil N pool, but the effects were different under different vegetations. Compared with other vegetations, corn farmland showed relative lower soil N pools in both root layer and under-root layer. Orange plantation, grapefruit plantation and peach plantation had higher soil N pools in root layer, but camphor plantation, eucalyptus plantation and peach plantation displayed higher soil N pools in under- root layer. However, higher NH4-N and NO3 -N contents were observed in root layer of corn farmland, but lower ones were detected in under- root layer of eucalyptus plantation. The results here provide some efficient data for regional N utilization, land using and environment construction.