Even in soils that contain relatively low amounts of plant-available calcium, that is still enough to supply all the calcium the grass requires. Why is that? Turfgrass uses relatively small amounts of calcium, somewhere in the range of 1.5 to 5 grams of calcium per square meter per year (0.3 to 1 pound calcium per 1000 ft² per year). Sandy soils with a low cation exchange capacity have the lowest levels of plant-available calcium, but that amount is still 10, 20, sometimes 30 times more than the grass will use in an entire year.

Nitrogen, conversely, is present in the soil at about 1/100^th the concentration of calcium, yet nitrogen is used by grass in about 10 times the amount as is calcium. In fact, at any one time during the year, a typical golf course putting green contains only about 5% of the nitrogen that the grass will use during the the year. Thus, we always get a response to nitrogen fertilizer, but it would be extremely rare to see a response to added calcium.

Working with Dr. Larry Stowell from PACE Turf, the Minimum Level for Sustainable Nutrition (MLSN) guidelines have been developed to provide information about managing soil nutrient levels that can help decrease inputs and costs, while still maintaining desired turf quality and playability levels. This video describes the MLSN approach to nutrient management and discusses the specific guidelines for calcium.