To allow a wide range of treatments, some factors have been grouped together. For example, the irrigation amount factor has been grouped with the irrigation type factor. This way it is possible to compare different types of irrigation with different amounts (Sprinkler irrigation 200ml versus Drip irrigation 300ml ).

For these factors:

1. Select the factor in the list.
2. Specify the type of factor.
3. Enter the level and their units.
4. Click +, if you need to add another type of the same factor.