jQuery Grid Plugin - jqGrid

How can i reset the filter in JQGrid and get back entire data?

Somehow i have to create parameters like:

_search false
filters {"groupOp":"AND","rules":[]}
nd      1363780609723
page    1
rows    20
sidx    application_name
sord    asc

I tried below code

var grid = $("#list");
grid.jqGrid('setGridParam',{search:false});
var postData = grid.jqGrid('getGridParam','postData');
$.extend(postData,{filters:""});
grid.trigger("reloadGrid",[{page:1}]);

But it generates the parameters like

_search false
filters
nd      1363780823111
page    1
rows    20
sidx    application_name
sord    asc

I just need to send filter parameter like this but don't know how

filters {"groupOp":"AND","rules":[]}