Tangerine bitter & fruit dropping too soon

I have a 6 year old tangerine tree giving fruit for past 3 years. Have been fertilizing and watering per nursery advice except no ammonium sulfate added until last year (this year adding 1 cup in spring, summer and fall per nursery advice). Fruit is falling off again this year, as in past 2 years - just after starting to turn color, about 2-inches diameter. That fruit is super bitter. Throwing it in the compost pile by the bushel this year.
It gets full sun from morning until about 3pm when shade from a nearby tree shades it for the rest of the day. Leaves, etc, all look healthy & no insects or diseased look. Soil test shows in the proper ranges.
I'm about out of ideas. Any ideas about what to do try?
Bob
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I see no one answered your question - your description indicates the tree is under stress of some kind. The most common problem for homeowner ("dooryard") citrus is being kept too moist. When the tree is young and vigorous its roots can outgrow the root rot problem but by the time it's well established root rot takes over.
If your citrus is getting the same amount of water as your lawn, it's getting way; too much. Also, if you have mulched around the base that has to be removed to allow everything to dry out. Citrus shouldn't have mulch, grass or thick weeds inside the drip line.
It may not be too late to save the tree, if you can clear out around the base and if it's not getting the same watering schedule as your vegetable garden or lawn, but the fruit will probably not improve for at least one year while the tree tries to recover. Keep it well fertilized and let it dry out thoroughly between waterings, especially at this time of year.
I have a 6 year old tangerine tree giving fruit for past 3 years. Have been fertilizing and watering per nursery advice except no ammonium sulfate added until last year (this year adding 1 cup in spring, summer and fall per nursery advice). Fruit is falling off again this year, as in past 2 years - just after starting to turn color, about 2-inches diameter. That fruit is super bitter. Throwing it in the compost pile by the bushel this year.
It gets full sun from morning until about 3pm when shade from a nearby tree shades it for the rest of the day. Leaves, etc, all look healthy & no insects or diseased look. Soil test shows in the proper ranges.
I'm about out of ideas. Any ideas about what to do try?
Bob
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Howdy, Jim. Drainage, etc., is fine. Gets no water unless it's watered by hand. Dry climate here - 1.5" in the last 6 months. I ended up adding some 10-10-10 stuff I had on hand and then added some ammonium sulfate per nursery advise.
It's now about 2 months later. Tree looks great, huge tangerine, much growth since Sept. Fruit has been ripening and dropping the last month or so. Still just as bitter as ever though - no change there.
I am noticing some bright yellow leaves now in one part of the tree. Leaves around each fruit are splotchy with light yellow. All other leaves are dark green.
About all the fruit is off now. Will cutting off a branch with bad fruit and leaves and make the rounds of the nurseries this weekend.
Any ideas?
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