Evaluation of an indirect method for leaf area index determination in the vineyard: Combined effects of cultivar, year and training system
DOI:
https://doi.org/10.5073/itis.1998.37.73-78Keywords:
gap fraction, leaf area index, training system, grapevine cultivarAbstract
The performance of the plant canopy analyzer LAI-2000 was evaluated in three seasons to estimate vineyard LAI (leafarea index) in the Bordeaux area. Measurements were made in a vertical-trellised vineyard with 5555 Semillon and Sauvignon blanc vines per ha, and with 2525 lyre-trained Cabernet franc vines per ha. Various LAI-2000 sampling protocols were tested and the data compared with destructive determinations. While the results from single vines a ere not satisfactory, very good relationships were obtained if five consecutive vines were used. In the vertical-trellised vineyard, a very accurate and direct estimate of LAI could be obtained with the LAI-2000 using a combination of "parallel" and "diagonal" sampling protocol. LAI values obtained by direct and LAI-2000 had a 1:1 correspondence and were identical for both, year and cultivar. For the lyre system, a local calibration was required, mainly because of the contribution of shoots, perennial vine parts and posts. This calibration was easily obtained by progressively removing leaves from the vines.Downloads
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