Why is Satsuma orange tree dropping all the buds
I have a satsuma tree planted in the ground, and it flowers really well. Probably over 50 flowers, but now that the small fruit started developing (like the size of an apple seed), so many of them are turning yellow and dropping off. I think probably only 20 are left at most, and seems more fall off every day! The same thing happened last year and I got NO remaining fruit, how come the fruit won't stay on this tree?
I did use a fertilizer once in a while, it was just an all-purpose fertilizer, do I need one specifically for citrus? and when are you supposed to fertilize?