can i sale my NA land part by part

No.  You can sell as you wish but not total land.

Any agricultural land, converted for a non-agricultural purpose can be used for such converted purpose within a year from the date of issue of the conversion , however there is no restriction to sell them in parts to various prospective buyers. 

Show title documents to a local prudent lawyer for appreciation of facts and professional advise since usage of the property has been changed from agriculture to non-agriculture.