I just received results from a water test that was sent off 4 weeks ago. Water testing is done 2x a year so I know what is in the water or what is not in the water. In our case, our water is too CLEAN! So clean, that it strips the soil of nutrients. In fact, we apply 10lbs/1000ft2 of calcitic lime monthly just to replenish the calcium lost through rainfall or irrigation. Different types of nutrients leach more than others. Nitrogen for example, is a heavy leacher. Phosphorous on the other hand, tends to hang around. Very rarely do we apply any kind of fertilizer with Phosphorous in it. Think of old concrete swimming pools. Swimming pool managers put calcium in the water to create a calcium balance between the water and the calcium in the concrete walls. If calcium becomes deficient in the water, it will erode to walls of calcium, causing the walls to deteriorate and the pool to leak! Water quality and soil chemistry are very similar.
Soil testing is done annually to test the health of the soils. However, just because a specific nutrient
is plentiful in the soil doesn't mean the plant is using it or able to uptake the nutrient. Therefore,
during the growing season, we rely on monthly tissue testing which tells me specifically what is
happening inside. It lists each nutrient found in the turfgrass sample and what percentage of each nutrient is present. We are able to tweak our annual fertility program to balance the needs of these 3 modes of testing.
David York, Ph.D in Pittsburgh, PA (Tournament Turf Labs) is used for all three testing applications. I prefer private labs over university settings due to the quicker turn around and more site specific advice.