# Laboratory Methods

Soil data users may require basic information, such as pH and bulk density according to well established standard methods in soil science. It is therefore recommended to collect these parameters for each soil sample. In data repositories acknowledged coding systems for field- and laboratory methods should be used to enhance methods documentation, data comparability and interoperability.

Overview of existing standards

Soil sample pretreatment for laboratory analysis are defined by ISO 11464:2006 and
DIN 19747:2009 . The national standard DIN 32645:2008-11 contains statistical approaches and calibration features for chemical analysis and describes limits of detection and determination under statistical replication conditions. Alternative methods on detection limits and calibration can be found within the international standard DIN ISO 11843-1ff series (see below). In Table 2 important standards for soil quality analysis are listed.

# Methods of Soil Analysis

The book series is a standard work in the US and collects lab and field methods in soil science within five parts: Physical and Mineralogical Methods, Microbial and Biochemical Properties, Chemical Methods, Physical Methods, and Mineralogical Methods.

# Handbook of Soil Investigation

Loose-leaf collection with relevant standards (12,195 pages, 15 folders, in German) for soil description and investigation as well soil assessment. These standards cover the whole range of soil investigation: selection of sampling locations, sample preparation, treatment and transportation, extraction and fractionation techniques, analytical measurements, and evaluation methods. Many of these standards are enshrined in German legislation. More than 300 standards of the Handbook of Soil investigation are cited in the Federal Soil Protection and Contaminated Sites Ordinance.

Table 2: recommended soil quality analysis as regulated by national or international standards

# VDLUFA Method Book “The Investigation of Soils”

Loose-leaf collection with seven supplements (1991-2016) . One of the main issues of VDLUFA (Association of German Agricultural Analytic and Research Institutes) is to establish uniform methods and evaluation principles in agricultural research. The methods book treats analysis on soil quality for agricultural issues, including methods which are not (yet) described in international ISO standards. The methods include sampling, determination of total element contents, characterization of organic matter, and many other soil chemical and physical analyses and field methods (Table 3).

Table 3: Recommended soil quality analysis as regulated by the VDLUFA Method Book (VDLUFA, 2016)

# Laboratory Methods for Soil Testing

This method book contains preferred analytical procedures for investigation of the most important soil parameters. This selection was discussed and agreed with the Geological Surveys of the Federal States in Germany. It was designed as a method database containing descriptions of analytical procedures, references to existing standards and method codes that link methods with analytical results in the laboratory database of the Federal Institute for Geosciences and Natural Resources (BGR). Information about the application range of analytical methods, plausibility of analytical results, restrictions, and common sources of errors are given in this documentation of laboratory methods.

# Handbook of Forestal Analytics

Loose-leaf collection with 5 supplements containing harmonized analytical methods for the resources soil/humus, plant and water in forest context, starting from sample preparation up to determination of physical and chemical parameters. Moreover the handbook provides a customized method coding system that was developed in order to enable complex documentation of analytical methods in a database and to make them evaluable and interoperable. Analytical methods and method codification are applied for the National Forest Soil Inventory in Germany and for Environmental monitoring in Europe. Several methods are based on accepted national and international standards (DIN, EN, ISO), which is tagged in the handbook. If there are deviations from certain standards, these are marked as well.

# Conflicts and solutions

Soil analytical methods which are described within VDLUFA Method Book are considered to be national standards. In Germany the VDLUFA Method Books for soil analyses are established as standard field and lab methods for soil quality analyses on national scale and compete with existing other national standards and ISO standards. Numerous soil analytical laboratories in Germany use these methods for a long time to ensure comparability of national data. However national standards may complicate data transfer to international databases and reduce comparability of data sets in international contexts. The future challenge will be to develop transfer procedures for soil quality methods and results within different countries. The establishment of an international IT-infrastructure on soil and agricultural data could be an important step on this process. The authors can give support to find and use derivation tools (if any exist) to transfer data that was acquired according to national standards into international standards (see Chapter 2.3).