Evaluation of three techniques for measuring grass leaf area1

Three leaf area measuring techniques were compared. Although statistical considerations received priority, practical issues such as economy of time, labour and finance, were also evaluated. The electronic light interception planimeter and the squared grid method (SGM) are already in common use, while computer‐aided image analysis (CAIA) is relatively unknown for grasses. Results indicated that the planimeter is significantly (P≤0.01) less precise and accurate than the other techniques, between which no significant (P>0.05) differences were detected. Individual SGM operators, although highly consistent within themselves, differed significantly (P≤0.01) in their respective abilities to measure absolute leaf area. It was concluded that, on a practical basis, the planimeter and CAIA were likely to be the most efficient in the long term, with CAIA being more reliable. Under situations of limited finance and equipment, the SGM would seem to be a viable alternative.