Relevance of the Lin's and Host hydropedological models to predict grape yield and wine quality

摘要

The adoption of precision agriculture in viticulture could be greatlyenhanced by the diffusion of straightforward and easy to be appliedhydropedological models, able to predict the spatial variability ofavailable soil water. The Lin's and Host hydropedological models wereapplied to standard soil series descriptions and hillslope position, topredict the distribution of hydrological functional units in two vineyardand their relevance for grape yield and wine quality. A three-years trialwas carried out in Chianti (Central Italy) on Sangiovese. The soils of thevineyards differentiated in structure, porosity and related hydropedologicalcharacteristics, as well as in salinity. Soil spatial variability was deeplyaffected by earth movement carried out before vine plantation. Six plotswere selected in the different hydrological functional units of the twovineyards, that is, at summit, backslope and footslope morphologicalpositions, to monitor soil hydrology, grape production and wine quality.Plot selection was based upon a cluster analysis of local slope, topographicwetness index (TWI), and cumulative moisture up to the root limiting layer,appreciated by means of a detailed combined geophysical survey. Watercontent, redox processes and temperature were monitored, as well as yield,phenological phases, and chemical analysis of grapes. The isotopic ratioδ13C was measured in the wine ethanol upon harvesting toevaluate the degree of stress suffered by vines. The grapes in each plotwere collected for wine making in small barrels. The wines obtained wereanalysed and submitted to a blind organoleptic testing.The results demonstrated that the combined application of the twohydropedological models can be used for the prevision of the moisture statusof soils cultivated with grape during summertime in Mediterranean climate.As correctly foreseen by the models, the amount of mean daily transpirablesoil water (TSW) during the growing season differed considerably between thevineyards and increased significantly along the three positions on slope inboth vineyards. The water accumulation along slope occurred in every year,even during the very dry 2006. The installation of indicators of reductionin soils (IRIS) tubes allowed confirmation of the occurrence of reductiveprocesses in the most shallow soil.Both Sangiovese grape yield and quality of wine were influenced by theinteraction between TSW content and salinity, sometimes contrary toexpectations. Therefore, the studied hydropedological models were notrelevant to predict grape yield and wine quality in all the hydrologicalfunctional units. The diffusion of hydropedological models in precisionviticulture could be boosted considering salinity along with topography andsoil hydrological characteristics.