DOI: 10.5281/zenodo.10065970
title: Database of topsoil  chemical and physical properties in Croatia

description: 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