khourshed, the more usual symptom is a pale leaf blade with green leaf veins.
With a bit of imagination you can discern a green 'triangle' (outlined by the yellowing edge) on the older leaves. You have probably seen the same symptom on older palm fronds - especially Phoenix canariensis, the Canary Island date palm. The symptom is related to magnesium deficiency,
I think that you have over applied iron and this may have depressed magnesium uptake (if I remember correctly).
Hence the browning along the edge (iron toxicity) and the green triangle (magnesium deficiency).
The brown sections should be crisp to the touch. If not, you might have something else.
Another pleasant fruit is the soursop, Annona muricata. It flavors ice cream exquisitely.

ronalawn82
thanks for your valuable information, time to look for Magnesium supplement for my tree

i will keep you updated

ps. never heard or see the soursop on Wikipedia the tree looks way richer than Sugar Apple does the fruit taste like Sugar apple ?

khourshed, the texture is creamy rather than grainy.
Here!

Khourshed, and also Here!

BTW, those yellowing leaves are not needed to be there. I would trim all of them. they are not functioning anymore. Also, prune any new branching starting at the bottom. You already have three branches.