Q.Meyer Lemon tree with yellow leaves
Planted last fall. Good growth, lots of blooms, lots of lemons coming on. Mostly full sun but the leaves are yellow. It is watered by drip every other day, 30 mins. and I have soaked it for hours to flush salts. No improvement. Then I used mixture of water/epsom salts for magnesium. Waited a week, no improvement. Then fish fertilizer for nitrogen. Waited a week, no improvement. I have deep watered for about 3 hours twice in the last month. Thank you for any suggestions you can provide.

You not only have yellowing leaves but, judging by the photo, your leaves look a little cupped/curled. This usually happens when trees are over-watered. I would ease up on the watering and monitor for signs of improvement.
For more information on meyer lemon trees, please visit the following link:
https://www.gardeningknowhow.com/edible/fruits/lemons/growing-meyer-lemons.htm