The crack is probably due to shifting soils, or because of too much clay becoming dry. Water the area, see if the crack closes. If wet and the crack doesn't close, fill the crack with soil. Get grass growing on loose dirt as soon as you can.
If wetted, the crack doesn't close, take a look at the slopes. Your slopes may be too steep. See if dirt is sloughing off as it becomes wet. If so, you need heavy equipment.

Teach a man to grow fish...
He can teach to catch fish...