THIS STUDY was carried out during 2013 and 2014 seasons to ……examine the effect of foliar application of seaweed extract four times at 1 to 8% as an alternative to mineral N fertilizers on growth, plant pigments, nutrients, namely N,P,K,Mg, Zn, Fe, Mn and Cu in the leaves, yield and fruit quality of ‘Taimour' mango trees. mineral N (1000 g N/ tree / year) was added at percentages 0.0 to 100% as inorganic source in the form of amonnium nitrate
Using the 50 to 75% mineral N source plus 1 to 2% seaweed extract gave good results on all the studied parameters comparing with using N as 100% mineral as well as when inorganic N was added at 0.0 or 25%?. Applying only inorganic was superior than not applying mineral N even when foliar application of seaweed extract at 8% was applied. The increasing content of the investigated parameters was significantly related to the reduction of mineral N percentage from 100 to 0.0 % and at the same time to increasing concentrations of seaweed extract from 0.0 to 8%. The results obtained in the present study indicates that four application of seaweed extract at 2% to Taimour mango trees , plus reduction of inorganic N fertilizers by 50% gave the best results regarding yield and fruit quality