Improving yield and fruit quality of date palm by organic fertilizer sources

Abstract: A field study was carried out during 2007 and 2008 seasons on twenty-six years old Zaghloul cultivar of date palm growing in clay silt soil. One level of nitrogen alone or plus P and K from mineral (ammonium nitrate alone or ammonium nitrate + calcium superphosphate + potassium sulphate, NPK) and organic sources [poultry /chicken manure (CM), cow dung (CD) and town refuse compost (TR)] were applied either alone or in combinations to study their influence on the yield and fruit physico-chemical quality. The results revealed that applying organic manure either alone or combined with mineral fertilizers increased palm yield and enhanced fruit colour as compared with mineral fertilization alone. CM and CD resulted in the best fruit weight, fruit flesh weight and length. Fruit TSS, anthocyanin and sugars content increased while, tannins content was decreased by CM and CD as compared with combining organic manure with NPK or mineral alone. However, fruit acidity was not affected by any of the treatments when compared among each others. In general, micronutrients contents were significantly higher in fruits by applying organic manure alone than organic manure combined with NPK or mineral fertilization alone. Organic manure fertilization alone (especially CM and CD) resulted in decreasing lead, cadmium, nitrate and nitrite content than mineral fertilization.