Biomass Deposition and Chemical Composition of Litterfall in Clonal Eucalyptus Plantations

ABSTRACT Productivity in clonal eucalyptus plantations depends on the genetic material and on the demand and cycling of nutrients, making studies that evaluate these requirements necessary. The aim of this study was to evaluate the effect of management (with and without thinning) on the deposition, chemical composition and nutrient contribution in litter at different clonal or stallion eucalyptus plantations. The experiment was conducted under a subdivided plot design for comparison of “clone” and “thinning” treatments. Plots were composed of eight different clonal and eucalyptus seed plantations, with subplots being areas where thinning was performed and areas without thinning. Litter deposition pattern associated to seasons was observed, with higher values in the spring and summer. The leaf fraction was more representative in relation to nutrients. Deposition values were close in most plantations. Nutritional contents were higher in leaves of areas with thinning in relation to the other areas.

摘要 无性系桉树人工林（clonal eucalyptus plantation）的生产力取决于遗传材料以及养分需求与循环过程，因此开展针对此类养分需求的评估研究具备必要性。本研究旨在评估经营措施（疏伐（thinning）与不疏伐）对不同无性系及实生桉树人工林凋落物（litter）的沉积量、化学组成及养分贡献的影响。本实验采用裂区设计（subdivided plot design），以比较"无性系"与"疏伐"两种处理的效应。实验主区由8个不同的无性系与实生桉树人工林构成，副区划分为实施疏伐的地块与未实施疏伐的地块。研究发现凋落物沉积量存在季节变化特征，春季与夏季的沉积量更高。就养分贡献而言，叶片组分更具代表性。多数人工林的凋落物沉积量水平相近。疏伐区域的叶片养分含量高于其他区域。