What I did was take some old white cotton bed sheets, tear them into 3 inch wide strips. Mix up white glue and water. Brush on the glue mix over the joint. Carefully apply the cotton strip over the gap, feather out the edges, then apply more glue mix. Let it dry, then paint the table top a light brown earth color. The joints are hard to see. As you add more ground cover they will be totally gone.
Steve