I received results today from the greens clippings I sent off Thursday. These grass clippings are analyzed for the exact nutrients the plant is using. It is a snapshot in time. Soil testing is also useful on an annual basis. However, there are a lot of other factors that affect nutrient uptake. For example, you could have an abundant nutrient in the soil but it isn't being taken up due to a pH issue. This is just another tool I occasionally use to make management decisions on our greens. It seems like no matter what I do or apply, Potassium always comes back low. This is odd considering we spread a granular Potassium product monthly and spray a foliar product weekly. This leads me to question the accuracy of this method. The key nutrient I want to see is Nitrogen.
Dr. David York with Tournament Turf Labs is my go to man. He studied at Penn State and Cornell.