The present study was executed in 2014 and 2015 seasons on 23-year-old Zebda mango trees grown in sandy soil under drip irrigation system at the experimental orchard of El-Kassasien Hort. Res. Station, Ismailia Governorate. This investigation aimed to study the possibility of using the organic nitrogen (chicken manure 3.21 % N) with bio nitrogen (biogen) fertilizers partially instead of completed mineral nitrogen (ammonium sulphate 20.6 %N).
Results revealed that reducing the percentage of mineral nitrogen from 100 % to 25 % and increasing organic nitrogen to 75 % with bio-fertilizers ( 100 g biogen /tree) had an announced promotion and increasing number and length of new shoots, number of leaves/ shoot , leaf area, N,P and K contents, number of initial and retention fruit set percentage and yield (kg/tree). Fruit weight and pulp firmness, TSS and vitamin C content were also increased. While, fruit peel thickness and juice acidity percentage were significantly decreased in comparison with the control treatment (100 % mineral N).
Conclusively, under the conditions of this study, 75 % of organic nitrogen (23.36 kg chicken manure/tree) + 25 % mineral nitrogen (1.21 kg ammonium sulphate/tree) with biogen bio-fertilizer at 100 g /tree was sufficient for minimizing mineral nitrogen fertilization to the quarter and increasing yield/tree by 41.50 % (average of the two seasons) with the best fruit quality of Zebda mango as compared with control treatment.