In response to environmental concerns regarding nutrient leaching and runoff into groundwater, lakes, and streams, regional best management practices (BMP) for soil fertility have been developed to assist managers in caring for turf while conserving and protecting hydro-systems. PRS™-probes are an effective tool for functionally measuring the soil supply of nutrients available to turf grass (Woods et al., 2006).

Woods et al. (2006) used the PRS™-probes to measure K⁺ supply, from six different rates of fertilizer K, in a calcareous sand putting green at Cornell University in Ithaca, NY. Their objective was to determine whether the supply rate of K⁺ measured with PRS™-probes correlated with leaf K⁺ in creeping bentgrass (Agrostis stolonifera). PRS™-probes were inserted vertically into the putting green in the root zone of the grass. The PRS™-probes were buried in the ground for 24 hours on 15 dates over a 17-month period. The authors concluded PRS™-probes are a useful tool in turf research because: 1) they can be used in situ and 2) they reflected the variability in soil K⁺ supply. The authors also realized the potential of PRS™ to measure the diffusion and release of K⁺ from non-exchangeable forms which, they hypothesized, would aid in improved understanding of turf response to added fertilizer K.

Figure 1. Differences among K⁺ supply rates from six K⁺ fertilizer rates (standard deviation = 1.7, n=60). These data aided the researcher in determining that on this sandy site K+ supply in year 1 influenced K⁺ supply rate in year 2.

1. Woods, M.S., Rossi, F.S., and Ketterings, Q.M. 2006. App. Turf. Sci. Online (ATS-2006-0323-01-RS). Potassium supply rate as measured by exchange membranes in a calcareous sand.