Effects of inter-annual climate variability on grape harvest timing in rainfed hilly vineyards of Piedmont (NW Italy)
From Firenze University Press Journal: Italian Journal of Agrometeorology
Giorgia Bagagiolo, Istituto per le Macchine Agricole e Movimento Terra (IMAMOTER), Consiglio Nazionale delle Ricerche (CNR)
Danilo Rabino, Istituto per le Macchine Agricole e Movimento Terra (IMAMOTER), Consiglio Nazionale delle Ricerche (CNR)
Marcella Biddoccu, Istituto per le Macchine Agricole e Movimento Terra (IMAMOTER), Consiglio Nazionale delle Ricerche (CNR)
Guido Nigrelli, Istituto di Ricerca per la Protezione Idrogeologica (IRPI), Consiglio Nazionale delle Ricerche (CNR)
Daniele Cat Berro, Società Meteorologica Italiana
Luca Mercalli, Società Meteorologica Italiana
Federico Spanna, Regione Piemonte — Settore Fitosanitario e Servizi Tecnico Scientifici
Giorgio Capello, Istituto per le Macchine Agricole e Movimento Terra (IMAMOTER), Consiglio Nazionale delle Ricerche (CNR)
Eugenio Cavallo, Istituto per le Macchine Agricole e Movimento Terra (IMAMOTER), Consiglio Nazionale delle Ricerche (CNR)
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. Not only an increase in temperature but a dramatic change in the frequency of extreme events, such as heat-waves, is also expected. In the last years, 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). Concerning viticulture, the climate effects significantly influence grape and wine quality (Mariani et al., 2009). 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 Pied-mont: Langhe, Roero and Monferrato was recognised as a UNESCO World Heritage Site for the outstanding land-scapes and the importance of vine-growing and winemaking in the Region (UNESCO, 2020).
The study of climate evolution and its environmental, economic, and social effects need to be monitored through its variations over time through a historical series of meteorological data. This kind of data represents an essential resource for agro-meteorology to understand the current and predictive dynamics, address agronomical choices, and finally determine their qualitative and quantitative effects on agricultural production. The availability of long-lasting, complete and accurate data series is a fundamental added value to predict and react to climate variability. Inter-annual climate variability determines effects on the beginning and duration of phenological stages and, ultimately, on the grape harvest and yield (Jones and Davis, 2000).
Grapevines have four primary developmental stages: (i) budbreak, (ii) flowering, (iii) veraison (beginning of maturation) and (iv) full ripeness (harvest). The time between these stages varies greatly with grape variety (Tomasi et al., 2011), and it is mainly influenced by the air temperature of the growth period (Mullins et al., 1992). Previous studies (Jones et al., 2005; Ramos et al., 2008) reported changes of 5–10 days for these stages per 1 °C of warming over the last 30–50 years averaged over several wine regions and varieties. In addition, the observed increase of warm days poses a threat to grape quality because it causes a situation of imbalance at maturity, concerning sugar content, acidity and phenolic and aromatic ripeness (Camps and Ramos, 2012).Climate change brings warmer conditions, generally associated with shorter intervals between phenological stages and earlier harvest occurrence (Tomasi et al., 2011).
The grape harvest timing is closely related to the aptitude of the vine to yield and ripen fruit to the opti-mum levels (Jones and Davis, 2000). In the Italian region of Veneto (NE Italy), grape maturity dates have trend-ed 19 days earlier over 45 years (1964–2009) for several varieties (Tomasi et al., 2011), and similar trends for the harvest dates were observed across numerous other locations in Europe (Jones et al., 2005) for many wine grape varieties. In the Spanish region of Penedès, an analysis of temperature and precipitation trends was correlated with the beginning and ending dates of grape harvest: the ripeness timing showed a continuous advance of between -0.7 and -1.1 days/year (Camps and Ramos, 2012). To our knowledge, no studies have been published correlating long-time climate and harvest data series in Piedmont region. It should be useful for examine the relationships between climate variables and the responses of grapevine in a context of climate change, with particular reference to the beginning and ending harvest dates.
The purpose of this work carried out in the Basso Monferrato, a rainfed hilly wine-growing area in Pied-mont, is to investigate: (i) the existence of trends within long-time climate data series, considering the vine grow-ing season, (ii) the existence of trends within harvest dates for some local wine grape varieties and (iii) the relationships between the considered climate variables and harvest parameters.
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