Leaf blade area estimate of Digitaria pentzii under different cutting heights

Abstract

Pasture studies require information on leaf area, as it is one of the main parameters for evaluation of plant growth. Thus, the objective of this study was to estimate the leaf blade area of pangolão grass (Digitaria pentzii Stent.) using non-destructive methods by regression model analysis. The experimental design consisted of randomized blocks, with three cutting heights (10, 15, and 20 cm) and four replications. Three hundred leaf blades of pangolão grass were randomly collected, and their respective lengths (L) and widths (W) determined using a digital caliper. The leaf blade area of pangolão grass was estimated by the gravimetric method, using linear and power regression models to explain the leaf blade area as a function of the product of L and maximum W. The real leaf blade area presented an average value of 18.64 cm², ranging from 4.29 to 45.95 cm². The leaf blade area of pangolão grass, regardless of cutting height, was estimated with greater accuracy by the power model. The power model, ?=LW1.007, can be used to estimate the leaf blade area of pangolão grass based on leaf blade L and W values. Keywords: modeling; non-destructive method; pangolão grass.