2006-2020年环江站喀斯特农田生态系统土壤物理性质数据集

中国科学院环江喀斯特生态系统观测研究站（本文中简称“环江站”）是我国西南喀斯特地区重要的农业生态系统长期野外定位观测研究站，是依照中国生态系统研究网络（Chinese Ecosystem Research Network，简称CERN）联网监测规范布置的试验样地。自2005年以来，环江站依照国家生态系统观测研究网络（National Ecosystem Research Network of China，简称CNERN）和CERN农田生态系统观测指标要求，逐一开展针对喀斯特峰丛洼地农田生态系统水分、土壤、生物、气象等环境要素的监测活动。 本数据集收集、整理了环江站2006–2020年8个长期联网监测样地的土壤机械组成与土壤容重数据。2006—2007年分别对综合观测场土壤生物水分采样地(HJAZH01ABC_01)、旱地辅助观测场土壤生物水分采样地(HJAFZ01ABC_01)、坡地草本饲料辅助观测场(HJAFZ02ABC_01)、坡地顺坡垦殖辅助观测场(HJAFZ03ABC_01)以土壤自然发生层采样分析了土壤机械组成;2015年增加四处不同作物类型的站区调查点———地罗村桑树生物土壤采样地(HJAZQ01AB0_01)、地罗村玉米地土壤生物长期采样地(HJAZQ01AB0_02)、清潭村经济作物土壤生物长期采样地(HJAZQ02AB0_01)、清潭村水田土壤生物长期采样地(HJAZQ02AB0_02),按中国生态系统研究网络(CERN)长期观测规范以固定分层采样分析土壤机械组成;坡地草本饲料辅助观测场(HJAFZ02ABC_01)、坡地顺坡垦殖辅助观测场(HJAFZ03ABC_01)两个观测场,因样地内土壤层浅薄,且为土石混合环境,未能采集得到可供分析的样品；期间分析得到的机械组成数据包括0.05-2mm沙粒含量、0.002-0.05mm粉粒含量、＜0.002mm黏粒含量、土壤质地名称4个分析指标。剖面土壤容重监测频率为每5年1次,分别在2006—2007年(环江站开始实施CERN长期观测规范)、2010年、2015年于作物收获季节开挖剖面,采用环刀法分层采取土壤容重样品；同时也由于样地内土壤层浅薄,且为土石混合环境,未能采集得到可供分析的样品，坡地草本饲料辅助观测场(HJAFZ02ABC_01)、坡地顺坡垦殖辅助观测场(HJAFZ03ABC_01)两个观测场在2015年、2020年两个采用年度中未能测得土壤容重数据。 本数据集反映了桂西北喀斯特峰丛洼地农业区传统代表性作物早晚稻、玉米、大豆、桑叶、柑橘等农作地土壤质地和土壤的结构性，可以为农业生产研究以及土壤改良提供依据,也可以为水土保持、环境演变等领域定量化推论提供基础数据。本数据集可协议进行共享。

The Huanjiang Karst Ecosystem Research Station, Chinese Academy of Sciences (hereinafter referred to as "Huanjiang Station" in this paper) is an important long-term field positioning observation and research station for agricultural ecosystems in the karst region of southwest China. Its experimental plots are laid out in accordance with the monitoring specifications of the Chinese Ecosystem Research Network (CERN). Since 2005, Huanjiang Station has successively carried out monitoring of environmental factors including water, soil, biology, and meteorology for the karst peak-cluster depression farmland ecosystem, in accordance with the observation index requirements of the National Ecosystem Research Network of China (CNERN) and the farmland ecosystem of CERN.

This dataset collects and organizes soil mechanical composition and soil bulk density data from 8 long-term networked monitoring plots at Huanjiang Station from 2006 to 2020. From 2006 to 2007, soil mechanical composition was analyzed by sampling according to natural soil genetic horizons at the comprehensive observation field soil biological and water sampling site (HJAZH01ABC_01), dry land auxiliary observation field soil biological and water sampling site (HJAFZ01ABC_01), sloping herbaceous feed auxiliary observation field (HJAFZ02ABC_01), and sloping land downslope reclamation auxiliary observation field (HJAFZ03ABC_01). In 2015, four survey sites in the station area with different crop types were added: mulberry biological soil sampling site in Luoluo Village (HJAZQ01AB0_01), long-term soil biological sampling site in corn field of Luoluo Village (HJAZQ01AB0_02), long-term soil biological sampling site in cash crop field of Qingtan Village (HJAZQ02AB0_01), and long-term soil biological sampling site in paddy field of Qingtan Village (HJAZQ02AB0_02). Soil mechanical composition was analyzed via fixed layered sampling in accordance with the long-term observation specifications of CERN. However, the two observation fields, sloping herbaceous feed auxiliary observation field (HJAFZ02ABC_01) and sloping land downslope reclamation auxiliary observation field (HJAFZ03ABC_01), failed to collect samples suitable for analysis due to the shallow soil layer and rock-soil mixed environment in their plots. The mechanical composition data obtained during this period include four analysis indicators: sand content (0.05–2 mm), silt content (0.002–0.05 mm), clay content (<0.002 mm), and soil texture name.

The monitoring frequency for profile soil bulk density is once every five years. Soil bulk density samples were collected via layered sampling with the ring knife method during crop harvesting seasons in 2006–2007 (when Huanjiang Station began implementing CERN long-term observation specifications), 2010, and 2015. Again, due to the shallow soil layer and rock-soil mixed environment in their plots, the two aforementioned observation fields failed to obtain measurable soil bulk density data in the 2015 and 2020 sampling years.

This dataset reflects the soil texture and soil structure of farmlands growing traditionally representative crops in the karst peak-cluster depression agricultural area of northwest Guangxi, including early and late rice, corn, soybean, mulberry leaves, citrus, etc. It can provide a basis for agricultural production research and soil improvement, as well as basic data for quantitative inference in fields such as soil and water conservation and environmental evolution. This dataset can be shared under agreement.