Methods for estimating leaf area in forages species

Leaf area is an important variable for ecophysiological studies since it plays an important role in light interception, photosynthesis, water and nutrient use, crop growth and development. Moreover, understanding the properties of the leaf area could provide valuable information regarding cultural practices such as irrigation, fertilization, pruning etc. Nevertheless, determination of the leaf area is not an easy task, and there has been a great variety of methods developed. We present the most frequently used, direct and indirect techniques to estimate leaf area in forage species, and their advantages and disadvantages are discussed. Direct methods usually require removing leaves and then determining the leaf area; these methods are destructive and require adequate, potentially expensive, equipment. Indirect, non-destructive, methods are user friendly, less expensive, and can provide accurate leaf area estimation. The latter methods offer reliable and inexpensive alternatives in horticultural experiments and may be also used to determine the relationship between leaf area and plant growth rate. However, selection of the most appropriate method for leaf area estimation should be based on experimental goals and available equipment.