Grass burning problem...help required
 

I have completed some landscaping that included the laying of a new lawn.

I have layed this over what was brick footings of old garden wall/shed.

They are about 12 18 inches below the finished surface.
I am now seeing the footprint of the footings as burn marks on the lawn.

I expect that the footings are leaching salt/other minerals and causing this
burning.
Without going to the BIG task of removing these footings is there anything I
can do to counter what is occurring?

In addition there are other burn marks on the lawn trhat I expect is from
soil originating from near or on the footings (before I started the
earthworks)

thanks in advance

-j