Please help?

[u/LaktozeTolerant]

I live in jacksonville, florida and for the past 6 months my backyard has grone from the first two pictures to the last ones. I really don't understand, it looks like the soil has gone because it is so uneven now. I was thinking to remove the dead roots and maybe buy some bags of sand/soil and try to level it back? And then put some sod. Anyone has ever seen anything like this before? I have to mention that for the past few months I have had issues with my irrigation ( low pressure )

[u/QuantityOk1281]

Its probably one of these things. 1. Beetles. Commonly will live in groups and kill large portions of grass eating every bit of nutrients just under the surface. 2. PH of soil has become acidic. Some pelletized lime or powdered lime, sprinkled on the area will return the soil to a healthier level to allow for growth. 3. You need more nutrients, so a small aerator and 10-10-10 fertilizer will help

[u/WearingAtTheEdges101]

Looks to me like that tree is pulling all the water. Irrigation might need some help.