Design Period

Experiment design

Every long-term experiment must have an experimental design. In the GLTEN metadata schema, the experiment design can include the following:

  • Experiment design, including the number of replicates and plots.
  • Crops and crop rotations.
  • Factors, also known as treatments and interventions.
  • Measurements and observations made.

Overtime LTEs modifications can be made to an experiment which change the overall design. The GLTEN metadata schema uses the Design Period concept to describe these significant changes. For example, in 1968 the [Broadbalk wheat experiment]( introduced crop rotations and modern short stem cultivars; in the GLTEN, this is treated as a separate design period to the preceding years.

Not every change needs to be documented as a different design period. The recommendation is to create a new design period for a significant change, such as introducing a new factor.

Optional fields

Harvests per year
Indicates the maximum number of harvests per year.
Indicates whether or not the experiment is factorial, i.e all combinations of factor levels are present in the experiment.


Add the crops grown on your experiment here. In most cases you shouldn’t specify cultivars or varieties here. If your LTE is evaluating different cultivars you should specify these as a Factor.

If crops are grown in rotation you can specify the rotation order in the next section.

Crop Rotations

The crop rotation section lets you describe the crop rotation(s) used in your experiment.

If you use crop rotation as a factor in your experiment you should still enter the rotations here and not in the Factors section. You should use the Is factor? option to indicate the crop rotation is a factor category.

For more detail on crop rotation terminology please review the crop rotations help.

Mandatory fields

Crop rotation name
This is a meaningful name for the rotation and is especially helpful if you have several different rotations.
Is factor
Check this box if crop rotations are used as an experimental factor.
Use this to state whether or not the rotation is fully phased (i.e. all phases of the rotation are present each year) or not.

Add each crop as a phase. The drop down list is generated from the list of crops added to the previous Crops section, so make sure you have added all the crops cultivated in the LTE design period (if not you can easily go back and add them).

If two crops occur in the same phase click the same phase button for the later crop. You now should see the two crops are now listed in the same phase.

Optional fields

Start Year and End Year
If the crop rotations have changed during the design period, use these fields to state when a specific rotation was used.


For more detail on factors terminology please review the factors help.

Measured Variables