Soil tests reveal what the nutrient levels are in the soil and tissue tests reveal what the nutrient levels are in the plant. I seldom see samples of both from the same field. When I do, it surprises me how different they can be. More important is the soil pH, or acidity, which determines nutrient availability in the soil. Soil tests should be done every three to five years.
Most growers base their fertilizer programs on soil tests.
But I don't think fruit growers should use that approach. Because perennials have a larger root system and recycle nutrients, tissue testing is a better means of determining plant nutrient needs. Growers are being penny wise and pound foolish to base their fertilizer programs on soil tests simply because the soil test is cheaper. Tissue tests should be done on a regular cycle every two to five years. Tissue tests give a accurate picture of the nutritional status of your plants.