A Simple Method to Estimate the LEAF Area INDEX Using Digital Camera in Irrigated Processing Tomato.

The leaf area index (LAI) is important information used in crop modellings. Usually, the LAI is obtained by destructive method with LI-COR equipment. The objective of this research was to develop a non-destructive method that uses photographs taken in situ and a public domain software (ImageJ). To validate the method, we used the irrigated processing tomato crop. Samples were taken at 15, 30, 45, 60, 75, 105, 130 days after planting. For the photographic method a ruler of 1m² was placed on the soil in 24 randomized sampling points, and for each point a photograph was taken. For each point, one plant was collected to obtain the LAI through the LI-COR method. The photographs were processed in ImageJ for LAI estimation. The comparison with destructive (LI-COR) and non-desctructive (photo) methods was evaluated by the mean absolute percentage error (MAPE), a measurement of accuracy, and R², a measurement of precision. The photographic method had high accuracy and precision, the MAPE and R² were 0.4% and 0.94, respectively.