PocketLAI: una smart-app per la determinazione in vigneto dei valori di LAI

The Leaf Area Index (LAI) measure in vineyard involves some critical issues, due to its non-homogeneous and discontinuous canopy that lead to a reduction of the measurements accuracy with the conventional tools. The study goal was to evaluate the suitability of an innovative smart-app, PocketLAI, in measuring the vineyard LAI (LAIv), and carry out the comparison with the performance of hemispherical photography (HP). The estimated LAIv values were compared with those from destructive and direct measurements. Six surveys were carried out on three sampling areas of different vigor in a vineyard. The results show good agreement between PocketLAI data and the direct measurements, especially for LAIv ranging between 0.13-1.41 (R2 = 0.94, RRMSE = 17.27%), while an accuracy decrease, due to a saturation effect, occurred including an outlier LAIv value (R2 = 0.77, RRMSE = 43.00%). The HP showed good agreement with direct measurement (R2 = 0.94), but a large over-estimation (RRMSE = 99.46%). PocketLAI has proved to be a valuable tool to monitor the spatial-temporal variability of vine vigour, as alternative to the traditional methods.