org-agenda-ndays

org-agenda-ndays is a variable defined in `org-agenda.el'.
Its value is

nil

• This variable is obsolete since 24.1;
  use `org-agenda-span' instead.

Documentation:
Number of days to include in overview display.
Should be 1 or 7.
Obsolete, see `org-agenda-span'.

You can customize this variable.