Weighted average of bulk density, coarse fragment by layer of the first and second campaign of the French Soil Quality Monitoring Network

The French Soil Quality Monitoring Network (RMQS) is a national program for the assessment and long-term monitoring of the quality of French soils. This network is based on the monitoring of 2240 sites representative of French soils and their land use. These sites are spread over the whole French territory (metropolitan and overseas) along a systematic square grid of 16 km x 16 km cells. The network covers a broad spectrum of climatic, soil and land-use conditions (croplands, permanent grasslands, woodlands, orchards and vineyards, natural or scarcely anthropogenic land and urban parkland). The physical, chemical and biological properties of the soil are measured on each site, during the first campaign and presently on the second campaign. The spatial and temporal variability of soil properties are explained by biophysical variables, sources of contamination, history of land-use and management practices on each plot. The first sampling campaign in metropolitan France took place from 2000 to 2009. This campaign focused on soil contamination assessment and made it possible to map key soil parameters (28 variables) as well as 12 trace metal elements and 70 persistent organic pollutants. The sampling method, measurements and observations on each site are described in the RMQS guidelines. The second campaign started in 2016 and should last 12 years. The soil tests were carried out on composite samples collected with an auger at two sampling layers: 0-30 cm or cultivated layer named “upper layer” or “layer 1” and 30-50 cm named “subsoil layer” or “layer 2”. Each composite sample was made up of 25 individual sample cores taken on a sampling area of 400 m², using an unaligned systematic sampling design (see description in the RMQS guidelines). In some cases, a third layer was made up of holorganic layers in forests or meadows, corresponding to pedological horizons OF and OH, when these layers were sufficiently thick, (at least 1 cm) and continuous over the sampling area. On each plot, were performed, on a pit, volumetric samples to measure bulk density and coarse fragment content. Usually three pseudo-replicates corresponding to both layer 1 and layer 2 and covering the thickness of each layer were sampled. For holorganic layers, bulk density was calculated from the composite sample, for which each elementary volume was measured. The dataset contains the results of bulk density and coarse fragment data from 2168 plots of the first campaign and their available layers and from 2137 plots of the 2nd campaign until 2022. The raw values of bulk density and coarse fragment content are not available here but corrected by layer by applying a weighting taking in account overlapping of samples.

法国土壤质量监测网络（RMQS）是一项用于评估法国土壤质量并开展长期监测的国家级项目。该网络依托2240个具有代表性的法国土壤及其土地利用类型监测站点，沿16千米×16千米的系统方格网分布，覆盖法国全境（包括本土与海外领地）。该网络涵盖了多样的气候、土壤与土地利用条件，涉及农田、永久草地、林地、果园与葡萄园、自然或轻度人为干扰土地以及城市公园绿地。
在每个监测站点，首轮采样与当前进行的第二轮采样均会测定土壤的物理、化学与生物学特性。土壤属性的空间与时间变异可通过生物物理变量、污染源、各地块的土地利用历史与管理措施进行解释。法国本土的首轮采样工作于2000年至2009年间开展，本次采样聚焦土壤污染评估，可绘制关键土壤参数（28个变量）、12种痕量金属元素以及70种持久性有机污染物的空间分布图。各站点的采样方法、测量流程与观测记录均在《RMQS指南》中有详细说明。
第二轮采样于2016年启动，计划持续12年。土壤样品采用钻孔法采集，在两个采样层获取混合样本：0-30厘米的耕作层（又称“上层”或“1层”），以及30-50厘米的亚土层（又称“下层”或“2层”）。每份混合样本由在400平方米采样区内采用非对齐系统采样法采集的25个独立土芯组成，具体采样方法详见《RMQS指南》。在部分森林或草甸的有机土层中，若采样区存在厚度至少1厘米且连续的土壤发生学OF与OH层，则可增设第三层采样。
在每个地块的挖掘坑中，采集体积样本以测定容重与粗碎屑含量。通常会采集3个伪重复样本，分别对应1层与2层，并覆盖各层的厚度。对于有机土层，容重通过混合样本计算得出，其中每个单元体积均已完成测量。本数据集包含首轮采样的2168个地块（含其可采样层）以及截至2022年第二轮采样的2137个地块的容重与粗碎屑数据。此处未提供容重与粗碎屑含量的原始数值，而是通过考虑样本重叠情况进行分层加权校正后的数据。