Need to disable the CK Editor programmatically for specific form fields?

New form method

function mymodule_settings_form() {
$form['foobar'] = array(
'#type' => 'textarea',
'#title' => t('foobar'),
'#default_value' => "foobar",
'#required' => FALSE,
'#wysiwyg' => FALSE,
);
 
return system_settings_form($form);
}
form alter method

function mymodule_form_alter(&$form, &$form_state, $form_id) {
if ($form_id == 'mymodule_settings_form') {
$form['foobar']['#wysiwyg'] = FALSE;
}
}