Database of topsoil chemical and physical properties in Croatia

Sources
Data for database is collected from four main sources: 

Data published in book "Martinović, J. and Vranković, A. (Editors), 1997. Baza podataka o hrvatskim tlima, I. Državna uprava za zaštitu prirode i okoliša, Zagreb" labeled as "martinovic_1997" in the database.

This source consists of 2199 pedological profiles sampled from 1963 to 1996, most of which include depth to bedrock information.
Data from project: "Spatial variability of trace and toxic metals in agricultural soils of Croatia", Ministry of Science and Education and Croatian Waters. Project leader: prof.dr.sc. Marija Romić from Faculty of Agriculture, Zagreb, labeled as "agricultural_2013".

Data are sampled from "database of properties and quality of agricultural soils of Croatia" on 8x8 km grid and consists only from top soil samples (0-30 cm). There are 811 samples in this database.
Data from the the project: "Change in soil carbon stocks and calculation of trends in total nitrogen and organic carbon in soil and C: N ratio", from Ministry of Environmental Protection and Energy, carried on by Croatian Geological Institute (HGI), the Croatian Forestry Institute (HŠI) and the Agricultural Land Agency (APZ).

This dataset consists of two subsets:

"azo_2013" - 2519 samples of topsoil (0-25 cm), from 1994 to 2004 for making of Geochemistry Atlas of Croatia
"azo_2016" - 742 locations were revisited during 2015-2016 and new samples are taken and analyzed in horizons 0-10 cm, 10-20 cm, 20-30 cm.
Network of piezometers
Description of sources 
Martinović, J. and Vranković, A. (Editors), 1997. Baza podataka o hrvatskim tlima (Database of Croatian Soils) 
The database contains data on soil profiles and covers the total area of the Republic of Croatia. Only data accepted by external control are entered in the Database, as well as those profiles for which there is a minimum data. External control of data reliability was performed by comparing the genetical-morphological characteristics of the soil determined by field research and the data of laboratory soil analyses. The profiles for which the field and laboratory analyses are found to differ are rejected. In addition to data on soil properties, basic data on pedogenetic factors are given. The soil profiles surveyed in the period 1963-1996 are entered in the database. The majority of data come from the Basic Pedological Map of Croatia (Osnovna pedološka karta Hrvatske - OPKH) project. The following are entered in the Database: 1347 profiles in volume I and 851 profiles in volume II, a total of 2198 pedological profiles
Spatial variability of trace and toxic metals in agricultural soils of Croatia, Project Leader: Marija Romić 
The problem of exposure of agricultural soils to different anthropogenic inputs of toxic metals, but also of other potentially toxic substances, has acquired global dimensions in the last decades. Besides atmospheric deposition, environmental dispersion of chemicals used in agriculture is an important factor directly affecting the natural soil functions, or indirectly endangering the biosphere by bioaccumulation and inclusion into the food chain. Metal concentrations in soil can be generally predicted starting with the element abundance in the parent material. The extent to which pedogenesis affects heavy metals distribution varies according to the prevailing factors affecting soil processes. Because of the toxicity to plants and animals, it is important to determine their content, forms and distribution. Such hypotheses may be tested by total metal content determination, as well as other elements relevant for geochemical valorization of the agricultural soils of Croatia. Thus, the spatial variability and baseline of elements in soils will be determined by means of relevant statistical and geostatistical methods. The maps of toxic metal distribution will be produced and the suitability of soils for agriculture will be assessed. GIS is increasingly used in environmental assessment studies because of its ability to superimpose different spatial information and to combine them with the results of statistical analysis, enabling thus the detection of complex spatial relationships among different parameters. Geostatistics and multivariate statistics has been widely used in geochemical studies to identify pollution sources and to apportion natural vs. anthropogenic contribution, establishing a geochemical background as well. The main objectives of the investigation are: (i) to provide a geochemical database relevant to the agricultural soils in Croatia; (ii) to provide a detailed information about the natural variability of the geochemical background which is pertinent to administrative and legal issues as well as to safety food production and environmental protection; (iii) presenting the influence of human and other environmental activities on the soil quality mainly regarding the toxic and trace metal contents, and (iv) we are going to observe the influence of natural conditions on regional differences which have been widely neglected so far, and have not been taken into account while national regulations and guidelines on soil toxic metal contents have been established.
Change in soil carbon stocks and calculation of trends in total nitrogen and organic carbon in soil and C: N ratio 
The project is funded by the Fund for Environmental Protection and Energy Efficiency within the Program "Upgrading and Development of the Environmental Information System and Improving the Monitoring and Reporting System on the State of the Environment in the Republic of Croatia", Component 2: Improving the Monitoring and Reporting System on the State of the Environment Croatia; improving the system of data collection and exchange and developing methodologies for their processing in accordance with the guidelines of the UNFCCC and the Kyoto Protocol defined by the IPCC (Intergovernmental Panel on Climate Change). 
The project holder is the Ministry of Environmental Protection and Energy, and the executors are the Croatian Geological Institute, the Croatian Forestry Institute and the Agricultural Land Agency.
In the period 2014-2017, field and laboratory research of soil conditions was conducted at 725 representative locations. General data on the location of sampling were collected, which contain administrative, locational, geographical and other data (relief, climatic and meteorological data, detailed data on land use and vegetation cover, description of surface soil properties).
Field soil sampling for each LULUCF land use category was performed according to a modified methodology described in the EU DG JRC (Joint Research Center) "Protocol for soil sampling to confirm changes in organic carbon stocks in the EU" by Stolbovoy et al. 2007 (Soil sampling protocol to certify the changes of organic carbon stock in mineral soil of the European Union - EU JRC). The protocol modifications aimed to ensure reporting under the UNFCCC and Kyoto protocols, i.e., to ensure compliance with the IPCC methodology. Soil sampling on forest land (FL) according to the JRC protocol is planned at two depths of 0-10 cm and 10 - 20 cm and an organic layer (list), but due to reporting requirements under the UNFCCC and Kyoto protocol, sampling was carried out at a depth of 20 - 30 cm. Land under crops (CL) was sampled at two depths (0-20 cm and 20-30 cm) and grasslands (GL), wetlands (WL), settlements (SL) and other land (OL) were sampled at three depths 0- 10, 10-20 and 20-30 cm. Geochemical analyzes were performed at depths of 0–10 and 20–30 cm for forest soils (FL) and for meadows and pastures (GL) while for soils under crops (CL) composite samples of 0–30 cm and 0–20 cm were analyzed.
Network of piezometers
To get a more accurate depth to bedrock parameter, positions of 812 piezometers are considered as they have at least 4 meters of depth to bedrock.
Description of database
Column names and descriptions:
Metadata columns:
site_key - unique identifier that identifies sample in source database source_db - label of source database source_sampled - label of organization/team who sampled and analyzed data site_obsdate - year of taking sample longitude_decimal_degrees - longitude in degrees in WGS84 geographical projection latitude_decimal_degrees - latitude in degrees in WGS84 geographical projection pedon_completeness_index - quality factor (0-100) taxgrtgroup - classification of sample according to WBR 2014/2016 classification 
Soil properties columns:
column name - property - measurement units - descriptionoc - Carbon, Organic - % wt - CMS analyte. Organic carbon is a measure of all organic forms of carbon in the soil, including organic carbon within minerals. n_tot_ncs - Nitrogen, Total NCS - % wt - Total nitrogen is a measure of all organic and inorganic nitrogen, including that found in nitrogen minerals.ca_mehlich3 - Calcium, Mehlich3 Extractable  - mg/kg - The calcium extracted by the Mehlich III solution. k_mehlich3 - Potassium, Mehlich3 Extractable - mg/kg - The potassium extracted by the Mehlich III solution. mg_mehlich3 - Magnesium, Mehlich3 Extractable - mg/kg - The magnesium extracted by the Mehlich III solution. p_mehlich3 - Phosphorus, Mehlich3 Extractable - mg/kg - The phosphorus extracted by the Mehlich III solution. cec_sum - Cation Exchange Capacity, Summary   cmol(+)/kg - The effective cation exchange capacity is calculated by BASE_SUM+AL_KCL. It is not calculated if soluble salts are present. It is reported as meq per 100 grams on a <2 mm base. CMS derived value default ec_satp - Electrical Conductivity , Saturation Extract - dS/m - The electrical conductivity of the saturation extract is used to estimate the concentration of salts in a sample, and provides inferences on cation concentration in solution and osmotic pressure. It is reported as mmhos per centimeter. caco3 - Carbonates - % wt - Carbonate in the < 2mm fraction is measured by CO2 evolution after acid treatment. It is reported as gravimetric percent CaCO3 on a <2 mm base, even though carbonates of Mg, Na, K, and Fe may be present and react with the acidph_h2o - pH, 1:1 Soil-Water Suspension - (NA) - The pH, 1:1 soil-water suspension is the pH of a sample measured in distilled water at a 1:1 soil:solution ratio. If wider ratios increase the pH, salts are indicated. ph_kcl - The pH, 1:1 soil-KCl suspension - (NA) - The pH, 1:1 soil-KCl suspension is the pH of a sample measured in 1.0N KCl at a 1:1 soil:solution ratio. If the pH in KCl < pH in water, Al+++ is indicated. total_clay - Clay, Total - % wt - Total clay is the soil separate with <0.002 mm particle diameter. Clay size carbonate is included. Total clay is reported as a weight percent of the <2 mm fraction. total_silt - Silt, Total - % wt - Total silt is the soil separate with 0.002 to 0.05 mm particle size. It is reported as a gravimetric percent on a <2 mm base. total_sand - Sand, Total - % wt - Total sand is the soil separate with 0.05 to 2.0 mm particle diameter. It is reported as a gravimetric percent on a <2 mm base. wpg2 - Coarse fragments - % wt - The weight fraction of particles with >2 mm diameter is reported as a gravimetric percent on a whole soil base. db_od Bulk Density, <2mm Fraction, Ovendry - g/cc - Bulk density, oven dry (105 C) is the weight per unit volume of the <2 mm fraction, with volume measured on oven dry (105 C) natural fabric (clods). It is reported as grams per cubic centimeter on a <2 mm base. dbr - Depth to bedrock - cm - Depth to the R horizon or similar

## 数据来源
本数据库的数据主要源自四大来源：

### 来源1：专著数据集
数据源自专著《Martinović, J. 与Vranković, A.（主编）, 1997. 克罗地亚土壤数据库. 克罗地亚国家自然与环境保护总局, 萨格勒布》，数据库中标记为"martinovic_1997"。
该来源包含1963年至1996年间采集的2199个土壤剖面，其中多数包含基岩埋深信息。

### 来源2：农业土壤痕量与有毒金属空间变异性项目
数据源自克罗地亚科学与教育部及克罗地亚水利厅资助的项目《克罗地亚农业土壤中痕量与有毒金属的空间变异性》，项目负责人为萨格勒布大学农学院Marija Romić教授（博士），数据库中标记为"agricultural_2013"。
该数据集采自《克罗地亚农业土壤属性与质量数据库》，采样网格为8×8公里，仅包含表层土壤（0~30厘米）样品，共计811份。

### 来源3：土壤碳库及碳氮趋势计算项目
数据源自克罗地亚环境与能源部资助的项目《土壤碳库变化及土壤全氮、有机碳与碳氮比趋势计算》，执行方为克罗地亚地质研究所（Croatian Geological Institute, HGI）、克罗地亚林业研究所（Croatian Forestry Institute, HŠI）与农业土地局（Agricultural Land Agency, APZ）。
该数据集包含两个子数据集：
1. "azo_2013"：1994年至2004年间为编制《克罗地亚地球化学图集》采集的2519份表层土壤（0~25厘米）样品；
2. "azo_2016"：2015年至2016年间对742个采样点进行重访后采集的新样品，采样层次为0~10厘米、10~20厘米及20~30厘米。

### 测压计网络
为获取更精准的基岩埋深参数，本数据集纳入812个测压计点位，这些点位的基岩埋深均不小于4米。

## 数据源详细说明
### 专著数据源《克罗地亚土壤数据库》（Martinović, J. 与Vranković, A.主编, 1997）
该数据库收录克罗地亚共和国全境的土壤剖面数据，仅纳入通过外部质量控制的数据集及具备最低有效数据量的土壤剖面。数据可靠性的外部质控通过比对野外调查获取的土壤发生形态学特征与实验室土壤分析结果完成，若野外与实验室分析结果存在显著差异，则该剖面数据将被剔除。除土壤属性数据外，数据库同时提供土壤发生学影响因子的基础信息。1963年至1996年间调查的土壤剖面均已纳入该数据库，其中多数数据源自《克罗地亚基础土壤图》（Osnovna pedološka karta Hrvatske, 简称OPKH）项目。数据库共收录第一卷1347个剖面、第二卷851个剖面，总计2198个土壤剖面。

### 农业土壤痕量与有毒金属空间变异性项目（项目负责人：Marija Romić）
近数十年来，农业土壤遭受各类人为源有毒金属及其他潜在有毒物质污染的问题已演变为全球性环境议题。除大气沉降外，农业化学品的环境扩散是直接影响土壤自然功能的重要因素，还可通过生物富集进入食物链，间接威胁生物圈安全。土壤中金属浓度通常可依据母质中的元素丰度进行预测，而土壤发生过程对重金属分布的影响程度则取决于主导土壤形成的各类因素。鉴于重金属对动植物具有毒性，明确其含量、赋存形态与空间分布至关重要。可通过测定金属全量及与克罗地亚农业土壤地球化学价值评估相关的其他元素含量，验证相关科学假说。本研究将借助相关统计与地统计方法，明确土壤中元素的空间变异特征与地球化学基线，绘制有毒金属空间分布图，并评估土壤农业适宜性。地理信息系统（GIS）因可叠加多源空间信息并结合统计分析结果，能够揭示不同参数间的复杂空间关联，正日益广泛应用于环境评估研究。地统计学与多元统计方法已被广泛用于地球化学研究，以识别污染源、区分自然与人为贡献并构建地球化学背景值。本调查的主要目标包括：
1. 构建适配克罗地亚农业土壤的地球化学数据库；
2. 提供地球化学背景自然变异性的详细数据，该数据可用于行政与法律合规、食品安全生产及环境保护等领域；
3. 阐明人类活动与其他环境过程对土壤质量的影响，重点关注有毒与痕量金属含量变化；
4. 分析自然条件对区域土壤差异的影响——此类影响此前被广泛忽视，且在制定国家土壤有毒金属含量相关法规与标准时未被纳入考量。

### 土壤碳库变化及趋势计算项目
本项目由克罗地亚环境与能源效率基金资助，隶属于"克罗地亚共和国环境信息系统升级与发展、环境状态监测与报告体系完善"计划的第二部分：完善克罗地亚环境状态监测与报告体系；优化数据收集与交换系统，并依据政府间气候变化专门委员会（Intergovernmental Panel on Climate Change, IPCC）制定的《联合国气候变化框架公约》（UNFCCC）与《京都议定书》（Kyoto Protocol）指南，研发数据处理方法。
本项目由克罗地亚环境与能源部牵头，执行方为克罗地亚地质研究所、克罗地亚林业研究所与农业土地局。
2014年至2017年间，研究团队在725个代表性采样点开展了土壤条件野外调查与实验室分析。收集的采样点位基础信息包含行政、定位、地理及其他相关数据（地形、气候与气象数据、土地利用与植被覆盖详细信息、表层土壤属性描述等）。
针对每一类土地利用、土地利用变化和林业（Land Use, Land-Use Change and Forestry, LULUCF）土地类型，野外土壤采样均采用经修正的欧盟联合研究中心（EU DG JRC）Stolbovoy等人2007年发布的《欧盟矿物土壤有机碳库变化验证土壤采样规程》（Soil sampling protocol to certify the changes of organic carbon stock in mineral soil of the European Union - EU JRC）。规程修改的目的是确保数据符合UNFCCC与《京都议定书》的报告要求，即遵循IPCC核算方法。按照原JRC规程，林地（Forest Land, FL）的采样层次应为0~10厘米、10~20厘米及有机层（枯落物层），但为满足UNFCCC与《京都议定书》的报告要求，实际采样深度调整为0~30厘米。耕地（Cropland, CL）的采样层次为0~20厘米与20~30厘米；草地（Grassland, GL）、湿地（Wetland, WL）、建设用地（Settlements, SL）及其他土地（Other Land, OL）的采样层次为0~10厘米、10~20厘米与20~30厘米。林地与草地的地球化学分析采样深度为0~10厘米与20~30厘米，耕地则分别分析0~30厘米与0~20厘米的混合样品。

## 数据库字段说明
### 元数据列
| 字段名 | 说明 |
|--------------------------|----------------------------------------------------------------------|
| site_key | 源数据库中用于唯一标识样品的标识符 |
| source_db | 源数据库的标记标签 |
| source_sampled | 负责样品采集与分析的机构/团队名称 |
| site_obsdate | 样品采集年份 |
| longitude_decimal_degrees | WGS84地理投影下的经度（十进制度单位） |
| latitude_decimal_degrees | WGS84地理投影下的纬度（十进制度单位） |
| pedon_completeness_index | 样品质量评分（取值范围0~100） |
| taxgrtgroup | 依据世界土壤资源参比基础（World Reference Base for Soil Resources, WBR）2014/2016版进行的土壤分类 |

### 土壤属性列
| 字段名 | 中文属性名称 | 计量单位 | 说明 |
|--------------|----------------------------|----------------|----------------------------------------------------------------------|
| oc | 有机碳 | % 质量分数 | CMS分析物。有机碳指土壤中所有形态的有机碳，包括矿物结合态有机碳。 |
| n_tot_ncs | 全氮（NCS） | % 质量分数 | 全氮指土壤中所有有机态与无机态氮，包括矿物结合态氮。 |
| ca_mehlich3 | 梅利奇3法提取钙 | mg/kg | 经梅利奇3浸提液提取的钙元素含量。 |
| k_mehlich3 | 梅利奇3法提取钾 | mg/kg | 经梅利奇3浸提液提取的钾元素含量。 |
| mg_mehlich3 | 梅利奇3法提取镁 | mg/kg | 经梅利奇3浸提液提取的镁元素含量。 |
| p_mehlich3 | 梅利奇3法提取磷 | mg/kg | 经梅利奇3浸提液提取的磷元素含量。 |
| cec_sum | 阳离子交换量（总量） | cmol(+)/kg | 有效阳离子交换量通过BASE_SUM+AL_KCL计算得到，若样品中存在可溶性盐则不计算该值。结果以<2mm粒径组分的每100克干土毫克当量数报告，为CMS默认衍生值。 |
| ec_satp | 饱和浸提液电导率 | dS/m | 饱和浸提液的电导率用于估算样品中盐浓度，可推断溶液中阳离子浓度与渗透压。结果以mmhos/cm报告。 |
| caco3 | 碳酸盐含量 | % 质量分数 | 采用酸解法释放CO₂的方式测定<2mm粒径组分中的碳酸盐含量，结果以<2mm粒径组分的质量分数报告，即使样品中存在镁、钠、钾、铁等碳酸盐并与酸发生反应。 |
| ph_h2o | 1:1土水比悬液pH | 无单位（NA） | 1:1土水比悬液pH指以1:1土水比在蒸馏水中制备的悬液的pH值，若增大水土比会导致pH升高，则表明样品中存在盐类。 |
| ph_kcl | 1:1土氯化钾悬液pH | 无单位（NA） | 1:1土氯化钾悬液pH指以1:1土比在1.0N氯化钾溶液中制备的悬液的pH值，若氯化钾悬液pH低于水悬液pH，则表明样品中存在Al³+。 |
| total_clay | 总黏粒含量 | % 质量分数 | 总黏粒指粒径<0.002mm的土壤颗粒组分，包含黏粒级碳酸盐。结果以<2mm粒径组分的质量分数报告。 |
| total_silt | 总粉粒含量 | % 质量分数 | 总粉粒指粒径0.002~0.05mm的土壤颗粒组分，结果以<2mm粒径组分的质量分数报告。 |
| total_sand | 总砂粒含量 | % 质量分数 | 总砂粒指粒径0.05~2.0mm的土壤颗粒组分，结果以<2mm粒径组分的质量分数报告。 |
| wpg2 | 粗碎屑含量 | % 质量分数 | 粗碎屑指粒径>2mm的颗粒组分的质量分数，以全土为基准报告。 |
| db_od | <2mm组分干容重 | g/cc | <2mm粒径组分的烘干（105℃）容重，即单位体积<2mm组分的烘干质量，体积通过烘干（105℃）原状土块（土团）测定。结果以<2mm粒径组分的克/立方厘米为单位报告。 |
| dbr | 基岩埋深 | cm | 指土壤R层或类似层次的埋深。 |