中文摘要：

为了阐明黄土丘陵沟壑区森林生态系统植物与土壤之间的养分循环关系,明确叶片与乔木层整体生态化学计量特征差异性,采用野外调查与室内分析相结合的方法对研究区内主要森林生态系统不同乔木器官和土壤C、N、P含量进行了测定,分析了叶片、乔木层和土壤化学计量特征及之间的关系。结果表明：研究区内森林生态系统乔木层平均C、N、P含量均显著低于叶片水平,表层土壤（0—10 cm）C、N含量以及C∶P、N∶P值均显著高于土壤（0—100 cm）平均值;叶片与乔木层及二者与土壤间的生态化学计量特征关系不同;乔木层平均C含量与降水呈显著正相关,乔木层平均P含量仅与海拔呈显著正相关,影响本地区植物生长状态的主要因素是降水。土壤平均C、N含量仅受土壤容重的影响,土壤平均P含量主要受土壤容重、温度和降水的影响。研究结果可以为黄土丘陵沟壑区人工林的建设和管理提供理论依据。

英文摘要：

To understand nutrient cycling and relationships between the soil and plants in forest ecosystems in the hilly-gully area of the Loess Plateau, combined field investigations and laboratory analyses were performed to study the ecological stoichiometry characteristics of trees and soil, and their relationships. The results showed that the carbon （C）, nitrogen （N）, and phosphorus （P） contents of leaves were significantly higher than that of trees, and the contents of the surface soil （0-10 cm） were higher than that in the soil layers （0-100 cm）. The relationship between the trees and soil, and between leaf and soil were inconsistent. In the tree layer, C was positively correlated with precipitation, and P was positively correlated with elevation. Therefore, the main factor affecting plant growth was precipitation. In the soil, C, N only affected by soil bulk density, and P has correlations with soil bulk density,temperature and precipitation. These results provide a theoretical basis for the development and management of plantations in the hilly-gully area of the Loess Plateau.