I know people who have done this....and think they were using it as a fertilizer. However, I would never do this. I've got to believe it has the potential of poisoning your soil. Living through Sandy here in NJ, I know of homeowners in our town that simply got a single high tide cycle of saltwater, and it killed a number of the plants in their yard. It seems some plants are very sensitive to increase salt....a friend lost all the yews in his yard.