LBA-ECO ND-30 WATER CHEMISTRY, RAINFALL EXCLUSION, KM 67, TAPAJOS NATIONAL FOREST

This data set reports the results of chemical analyses of rainfall, throughfall, litter leachate, and soil water samples collected before, during, and after a rainfall exclusion experiment conducted at the km 67 Seca Floresta site, Tapajos National Forest, Brazil. Samples were collected every two weeks from May 17, 1999 through May 10, 2006. Measurements included alkalinity, conductivity, pH, and selected anions and cations analyzed by ion chromatography.

The exclusion treatment, began in late January 2000 and continued through December 2004, involved diverting about 60% of throughfall (equivalent to approximately half the rainfall) from a 1-hectare plot using plastic panels installed in the understory. The comparable 1-hectare control plot was unaltered. The purpose was to observe the potential effects of severe water stress on a humid Amazonian forest (Nepstad et al., 2002 and Nepstad et al., 2007). There are five comma-delimited data files with this data set.

本数据集记录了巴西塔帕若斯国家森林公园（Tapajos National Forest）67公里处Seca Floresta样地开展的降雨排除实验前后及实验期间采集的降雨、穿透雨（throughfall）、枯落物渗滤液（litter leachate）与土壤水样品的化学分析结果。样品采集周期为1999年5月17日至2006年5月10日，每两周采集一次样品。测定指标包括碱度、电导率、pH值，以及通过离子色谱法（ion chromatography）分析的部分阴离子与阳离子。
该降雨排除处理于2000年1月下旬启动，持续至2004年12月，通过在林下层（understory）安装塑料面板，截留1公顷样地内约60%的穿透雨，该截留量约相当于总降雨量的一半。与之对应的1公顷对照样地（control plot）未做任何人工改动。本实验旨在探究重度水分胁迫（water stress）对湿润亚马孙森林的潜在影响（Nepstad等，2002；Nepstad等，2007）。本数据集包含5个以逗号为分隔符的数据文件。