Estimating leaf area and leaf area index in VSP trained grapevines under different management systems (Vitis vinifera L. cv. Riesling)

Abstract

The aim of this study was to validate and implement different non-destructive methods of leaf area and leaf area index (LAI) determination in VSP trained grapevines (Vitis vinifera L. cv. Riesling) in a field trial comparing different management systems (i.e. integrated (GAP) and two different organic (European Union Regulation 834/07) management systems). 

For leaf area determination of primary and secondary shoots the models of Mabrouk and Carbonneau (1996) and of Lopes and Pinto (2005) were evaluated. Indirect measurements of LAI were conducted using the LAI-2200 Plant Canopy Analyzer (Li-Cor, Lincoln, NE, USA). Direct leaf area was measured using LI-3100 Area Meter (Li-Cor, Lincoln, NE, USA).

The model of Mabrouk and Carbonneau (1996) showed reliable results for secondary shoots. The correlation between direct and estimated leaf area of primary shoots of the different management systems was weaker. This was due to shorter internode lengths in the organic compared to the integrated system. Leaf area determination according to Lopes and Pinto (2005) showed to be a very accurate estimate of leaf area for both primary and secondary shoots of the different management systems. The application of the LAI-2200 showed to give an accurate prediction of direct LAI although it underestimated it systematically.

The application of the validated methods showed that vines of the organic treatment had significantly smaller secondary leaf area and a significantly lower LAI compared to the integrated treatment.