Turf Growth and Performance Evaluation Based on Turf Biomass and Tiller Density

Visual rating systems are often used for evaluating turfs because of the absence of biological criteria associated with growth and performance. The purpose of this paper is to examine whether describing turfs quantitatively in terms of their biomass and tiller density can contribute to our understanding of turf growth, and form the basis of an objective, quantitative system of turf assessment. Measurements of the aboveground biomass, and the corresponding tiller densities of turfs, were gathered mostly from published work. The data indicate that turfs, like many crowded populations of plants, are governed by a rule of population biology called the power, or thinning, rule. As applied to turfs, conformity to the power rule means that biomass is highest at the lowest tiller densities, with the consequence that very hard‐wearing turfs may inevitably be coarse textured. Estimates of the upper limits to biomass at tiller densities commonly found in turfs of different texture, suggest that there is more potential for the improvement of coarse turfs than fine ones. For turf assessment, biomass (alone or divided by tiller density to estimate mean tiller mass), is a useful guide to wear resistance. A measure of the fineness of turf texture is proposed. The use of biomass density (biomass divided by turf height) as a predictor of golf ball roll and lie is discussed. When turfs are at full cover, one of the parameters of the power rule, the biomass intercept log c, which can be derived from single measurements of biomass and tiller density, is proposed as a measure of the ability of turfs to accumulate biomass. Log c has the advantage of being independent of tiller density and of differences in nonlimiting management resources