I have a manderin orange fruit tree about 25 years old that has been producing every year and this year had only three oranges. What could be the problem? Do fruit trees ever get old? I am guessing as to the type of orange but the oranges are small and sweet. It was fertilized three to five years ago.
Maricopa County Arizona citrus
Mandarin citrus are noted for their potential for alternate bearing--defined as producing big crops one year, followed by light to no production the following year. The key to your problem is that you have not fertilized in 3 to 5 years. Citrus are heavy nutrient feeders, especially in years when they fruit heavily. My recommendation is an annual fertilization program, following guidelines recommended by Univ. of Arizona cooperative extension program.
In addition to fertilizer, it is important to provide supplemental water during the bloom period. Dry soil before, during and after bloom will increase fruit abortion.
second orange tree question: My naval orange was wonderful when new and for many years. Its about 20 years old, but now has changed as far as taste and size of segments. They are no longer tart and very sweet. It was also fertilized about 3-5 years ago. Does it have to be fertilized every year?
Fertilizing every year stimulates more regular crops of fruit and better foliage condition, both of which play important roles in the quality of fruit produced