研究区域位于昆仑山脉为界的青藏高寒区和塔克拉玛干沙漠之间,植被稀少,生态系统结构简单,稳定性差。中国科学院新疆策勒荒漠草地生态系统国家野外科学观测研究站(以下简称“策勒站”)自2005年加入中国生态系统研究网络(Chinese Ecosystem Research Network,CERN)以来,按统一的监测规范,对荒漠生态系统中土壤营养元素、主要理化性质及重金属含量等指标进行长期定位监测。本数据集收集整理了策勒站2009–2015年3个荒漠观测场和7个农田观测场长期采样地0–10、10–20、20–40、40–60、60–80、80–100 cm土层土壤的交换量、养分全量、矿质全量、微量元素和重金属元素、速效微量元素、机械组成及容重等42项指标。本数据集可为荒漠系统大气–土壤–植物生物地球化学循环过程提供基础数据,为荒漠生态系统修复和保育提供理论参考。
CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR Inc. and LI-COR, 820) from Aug. to Oct. of 1999, Apr. to Jul. of 2000, and from Aug. 2002 to Sept. 2003. Based on the collected dada, the diurnal and seasonal dynamics of profiles and storage of carbon dioxide in the forest were analyzed. The diurnal CO2 profiles showed that the vertical distribution of CO2 concentration were different for daytime and nighttime, and the CO2 concentration was highest close to forest floor, no matter at daytime and nighttime. The seasonal profiles of CO2 showed that stratification in the canopy was evident during growth season. CO2 concentrations at different heights (60 m to 2.5 m) had a little change in March, with a difference of 10 mmolmol-1, but had a significant change in July, with a difference of 60 mmolmol-1. In July, there also existed a greater gradient of CO2 concentrations at canopy (22, 26 and 32 m), with a difference of 8 mmolmol-1. The calculated total storage (ΔC/Δt ) of CO2 in the air column with height of 40 m beneath eddy covariance instrument was negative, and made a little contribution to NEE.
