An article in February issue of Fine Gardening Magazine recommends watering the plants with 2 inches of water weekly for 2 months and applying gypsum. Aerating the soil will also help with compaction. I would use a garden fork to make holes in the ground around your plants. I would also put a couple of inches of compost on the surface of the soil. Do not fertilize with chemical based fertilizers that are also high in salts.