A survey of soil nutrient analyses from turfgrass sites in Asia, Europe, and North America

Abstract

From 2013 to 2015, turfgrass managers from around the world were invited to submit soil samples from good-performing turf. A total of 162 samples, submitted from 10 countries and 42 unique sites across three continents, were analyzed using identical procedures at Brookside Laboratories (Ohio, USA). This global soil survey (GSS) was conducted to assess soil nutrient levels producing good turf, and to compare those results to conventional guidelines and to the minimum levels for sustainable nutrition (MLSN) data. Because each sample from the GSS was collected from good-performing turfgrass, the results represent a distribution of soil nutrient levels that can produce good turf. The pH of these samples ranged from 4.6 to 8.2 with a median of 6.5. Soil organic matter by mass loss on ignition at 360 ◦C ranged from 1.7 g/kg to 102 g/kg with a median of 18 g/kg. Soil nutrients were extracted by Mehlich 3. Median values for K, P, Ca, Mg, and S respectively, were 60, 68, 586, 76 and 14 mg/kg. Additional tests for P were done by Olsen (median of 15 mg/kg) and Bray 2 (median of 90 mg/kg) extractions. The soil organic matter and nutrient content of these survey results can be represented as continuous data from lognormal distributions. Soil pH was best represented by a normal distribution. The distribution of soil test results from the GSS show similar properties compared to the MLSN data. The nutrient contents of the GSS samples are lower than the levels recommended by conventional guidelines used in turfgrass soil test interpretation.