Effects of inter-annual climate variability on grape harvest timing in rainfed hilly vineyards of Piedmont (NW Italy)

Giorgia Bagagiolo,Guido Nigrelli,Eugenio Cavallo,Danilo Rabino,Federico Spanna,Luca Mercalli,Giorgio Capello,Daniele Cat Berro,Marcella Biddoccu

doi:10.36253/ijam-1083

Abstract

The current scenario of global warming impacts viticulture, influencing grape and wine quality. A study was carried out in the “Basso Monferrato” region, a rainfed hilly vine-growing area in NW Italy, to investigate the relationships between climate variables and grape harvest dates. The dates of harvest for some local wine grape varieties were recorded from 1962 to 2019 in the Vezzolano Experimental Farm and surrounding vineyards. Three series of climate data were investigated by means of trend analysis for temperature variables, Huglin index, and precipitation during the growing period. A significant trend was found for temperature variables (positive) and harvest dates (negative), indicating anticipation of harvest beginning from 11.6 to 34.2 days in the 58-years study period, depending on the variety. The influence of increasing temperature and Huglin index in anticipating the harvest period, particularly the harvest beginning, was also highly significant for all the considered varieties and vineyards in the Monferrato area. Implication under a climate warming scenario, the relevance of having available continuous and homogeneous datasets and possible future studies were also discussed.

Highlights

The Global Warming of 1.5 °C IPCC special report (IPCC, 2018) clearly highlights and documents the numerous effects of the observed climate changes on natural and human activities
The mean amount of precipitation, which showed high inter-annual variability, ranged from 402.2 mm to 656.9 mm across the three series while the Huglin index ranged from 1917.0 to 2590.2 degree-days per year. For those variables related to temperature, the mean values including in the computation the months of January and February resulted in being lower on average, 3.5 °C difference among minimum temperatures and 4.2 °C difference among maximum temperatures
This study contributed to understand how climate change and, in particular, the increasing trends of temperatures observed in the last decades are affecting the harvest period of grapevine in the Basso Monferrato wine-growing area

Summary

Introduction

The Global Warming of 1.5 °C IPCC special report (IPCC, 2018) clearly highlights and documents the numerous effects of the observed climate changes on natural and human activities. Many studies investigated the sharp impacts of climate change on different agricultural sectors (Jones and Davis, 2000; Jones et al, 2005; Jones, 2007; Moriondo and Bindi, 2007; Tomasi et al, 2011; Ramos, 2017; Kociper et al, 2019). Grapevine (Vitis vinifera L.) growing is one of the most relevant agricultural sectors in Italy, with 708.000 ha, ranking at the third position in Europe for vineyard cultivation, after Spain and France (OIV, 2020). The Piedmont region (NW Italy) has a vineyard surface of 41.360 ha, almost totally devoted to wine production (ISTAT, 2020). In 2014 The Vineyard Landscape of Piedmont: Langhe, Roero and Monferrato was recognised as a UNESCO World Heritage Site for the outstanding landscapes and the importance of vine-growing and winemaking in the Region (UNESCO, 2020)

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