The Leaves on my Lemon Tree are Turning Yellow

Can anyone tell me what is wrong with my little lemon tree? It was growing fine, and now all of a sudden the leaves are turning yellow. The soil is acidic, so I am not sure what the problem is. Does anyone know what is causing this?

there is possible reason that you take too much water on lemon trees and you lemon trees might be rotten and can no longer uptake nutrients or You may have poor drainage around the roots or an extremely heavy soil.
Citrus need to be watered about once a week and the soil should be kept
a little moist but not soaked.