1. Excavate the top 4-6 ins layer of dirt and fill back up with new topsoil of good quality., o* H* o) G0 ~' L5 a6 l J
2. Reduce the use of chemical fertilizer and use organic one instead.
/ @/ g% Q* |% x( w& l8 U/ c
I should tell a bobcat is required if you wanna do the whole front/back yard OR just spot-excavation (dig a bigger and deeper than normal hole, dump the old dirt and back fill w/ good topsoil when you want to plant a new tree) if you gonna do the job yourself.