United States Department of Agriculture
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Frequently Asked Questions

The characterization reports have changed. What are the main differences?

  1. New data tiers were created to group physical and chemical data and to report more data. Each tier has a name for easy reference. Tiers are only printed if they contain data. Columns on the tiers do not shift as before.
  2. If data were determined for more than one procedure, then additional tiers are printed.
  3. If data were determined for more than one preparation or instrument, then additional rows are printed with footnotes.
  4. Calculated values are stored. Previously, they were re-calculated for each report.
  5. The revised soil name is selected from the most recent classification date.
  6. The NASIS (National Soil Information System) database is the source for the pedon description report; therefore, the availability of the report is conditional on the availability of data in NASIS.

When are the data from current projects available on the Web?

Only data from completed projects are posted to the Web. A project is complete after the project coordinator reviews it and releases it for publication. Data from currently ongoing projects are stored in our laboratory information management system. Provisional data from the laboratory information management system are available by request.

Which trace-and-dash option should I select when I download data?

The notation “trace” indicates that a value is below the reliable detection limit or is less than the reporting limit. A dash indicates that the analysis detected no analyte.

The option to maintain the trace-and-dash notation creates reports in alphanumeric format. The option to replace the trace-and-dash notation with “0” or null creates reports in numeric format and is especially useful for data computations.

How do I decipher the column headings when I download data?

Each tier of data has a companion file consisting of a data dictionary. The file has a name similar to that of the data file but includes “_dict.” The data dictionary has a row of explanatory information for each column heading. The column heading is a concatenated list of data attributes. The list includes, in order, the analyte, procedure, preparation, unit of measure, instrument, origin, and two placeholders.

For example, CaCO3_6E1a_Sjj_% wt_0_CMS_0_0 is a possible column heading. “CaCO3” is the analyte name; “6E1a” is the procedure code; “Sjj” is the sample preparation code; “% wt” is the unit of measure; “0” indicates no instrument or instrument unknown; “CMS” is the symbol for the legacy data that was converted from a mainframe database (“LIMS” is used as the symbol for data from the current system); and the last two zeros are placeholders. The underscore (_) is a delimiter for each part. It is also used in analytes that have an associated extraction solution (e.g. Al_KCl). All of the specific information about the column heading is in the data dictionary files.

Why is more than one column produced for an analyte when I download data?

The column heading is composed of a concatenated list of data attributes. If any of the data attributes included in the column heading change, then a new column is created. This feature allows the user to understand the origin of the data and make informed decisions concerning data usage. The column number associated with the tier report is stored in the data dictionary file for reference.

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