Q.My lemon tree is not flowering this year
My lemon tree was bearing good fruit but for the last two years it was flowering, it has not given any fruit. This year it is not flowering.
If I understand correctly, your lemon has been fruiting well, until a couple of years ago when the fruit started to drop, and this year it's not even flowering. If you've been fertilizing all along, it seems most likely that either water or light has changed. One thing, have you been increasing the water as the tree grows? The other thing which I'm thinking is that other plants have been growing and shading the lemon more and more; this would make the lemon fruit less and less as years go by. So you can try providing more water, and trimming other plants that may be shading, and follow up with the information in this article: https://www.gardeningknowhow.com/edible/fruits/lemons/lemon-tree-not-fruiting.htm