Field experiment was carried out under drip irrigation system for examining the impact of organic farming practices on production of two potato varieties grown on sandy soil.Cornposting of plant residues and animal manure was occurred in different combinations. Results showed that potato tuber yield and N uptake were frequently affected by compost treatments. In most of the compost treatments, both yield and N uptake were enhanced by application of compost either alone or in combination with chemical fertilizer. Nitrogen uptake by tubers from chemical fertilizer was higher in case of totally fertilized treatment than those treated with combined treatment indicating the dependence of plants on the portion of N derived from compost when organic amendments were applied. Consequently,the efficiency of chemical fertilizer used by tubers was higher when the plants totally fertilized with mineral N than when combined with organic compost. Similar trend was noticed with 15N recovery by tubers.Approximately,all measured parameters were higher with spunta variety than those recorded with burn variety.