How to Retain Nutrients on Calcerous Sand Greens

Nitrogen usually gets the most attention when it comes to fertilization, and there are good reasons for that. It's the nutrient with the most visual effect and results in the greatest effects to the plant. However potassium (K) is also essential, as is phosphorous (P). We all know how to apply nitrogen using the range of fertilizer sources available today to superintendents and field managers. But what about P and K? Can we put on large amounts once or twice a year and have good results, or is the management more complicated than that? In most soils, few applications are just fine, but in the modified root zones that we often deal with fertilization practices may not be that straightforward. This may be the particular case with calcareous sands that are found throughout North America, but are common in the intermountain West. Sands in general leach quickly, but to compound the low nutrient-holding capacity, the high pH of these sands often limits the availability of many important nutrients. In most cases, new sand root zones quickly gain cation exchange capacity because of the large amounts of organic matter deposited from the growing turfgrasses. However, sometimes in calcareous sands, this organic matter deposition is delayed because of slow turfgrass growth. Also, turf grown on these sands sometimes has substantial thatch layers because of low microbial activity. To gain more information on proper management of these sands, we studied nitrogen (N), P, and K and their interactions on a creeping bentgrass (Agrostis stolonifera Huds.) green built with the calcareous sands common to the intermountain West region of North America. P levels can be maintained at