Soil testing of putting greens for desired species

Abstract Evidence is provided for the proposition that soil analysis should be interpreted for dominance of Agrostis capillaris over Poa annua in putting greens. Using a database of soil analysis results and golf green species composition, 64 combinations of test results were devised. Each was evaluated for statistical difference between A. capillaris and P. annua for three increments of cation exchange capacity (CEC) and pH. Boxplot increments with pH were assessed for separation between A. capillaris means and P. annua interquartile zones. Inconsistent results were eliminated. The test results most suitable for interpretation were K + Mg 10.8 (%BS), Mg 5.7 (%BS), K 3.4 (%BS). The target zone for A. capillaris dominance is the area below P. annua quartile 1 representing 81.5%–92.5% of A. capillaris , alternatively pOH/K+Mg 0.8 (%BS), pOH/K 2.6 (%BS), and CEC 8 (meq/100 g) could be used with 78.1%–91.8% of A. capillaris above P. annua quartile 1. CEC could be used with either option but is only valid <20 (meq/100 g).