El metamorfismo del sector El Vellon-Pedrezuela (Sistema Central Español)

El presente trabajo aborda el estudio metamorfico del sector «El Vellon - Pedrezuela». Mediante la determinación de los diferentes tipos de paragenesis minerales que contienen los materiales que afloran en este sector (metapelitas. metasamitas. anfibolitas y rocas calcosiiicatadas). de sus relaciones interminerales y de sus penodos de blastesis. se establece un metamorfismo regional progresivo de grado medio. Dicho metamorfismo se caracteriza por unas condiciones de 5.25 Kbar y 550 UC para un periodo de interfase yariando estas durante la segunda fase a 4 4 0.5 Kbar y 600 JC. Ei gradiente metamorfico aumenta di: 26 oC/Km. a 380 4 5 oC/Km desde el periodo de interfase a la segunda fase hercinica

Variability in grape composition and phenology of 'Tempranillo' in zones located at different elevations and with differences in the climatic conditions

The objective of this research was to analyse the variability on phenology and berry composition of 'Tempranillo' among different elevations and different climatic conditions. The study was conducted on 'Tempranillo' vineyards located in Rioja DOCa at elevations between 367 and 650 m a.s.l. Phenology and the evolution of berry composition during ripening, related to pH, total acidity, malic acid, total anthocyanins, total polyphenols index, colour intensity and sugar content were analysed for the period 2008-2018 at each elevation. The weather conditions recorded during the period of study were evaluated. The results indicate that, on average, differences between the analysed elevations of up to 21 days existed in the dates in which the maturity was reached, being the differences higher in the years with extreme conditions (very wet or dry and very hot or cool). The comparative analysis among elevations and in years with differences in temperature and in precipitation allowed knowing the differences in the vine response under different climatic conditions. From this analysis some conclusions may be extracted that may be useful for police makers to define new planting areas in which less imbalanced situations may occur under warm conditions

Interannual and spatial variability of grape composition in the Rioja DOCa show better resilience of cv. graciano than cv. tempranillo under a warming scenario

Weather conditions affect vine development and grape composition, although the response may be different depending on the variety and altitude. Under scenarios of climate change, the knowledge of the relationships between grape composition and climate is therefore important to know the suitability of a given cultivar. In this research, the variability of the grape composition of two red varieties with different phenological timings (Vitis vinifera L. cv. Tempranillo and Graciano) cultivated in Rioja DOCa (Spain) and the climatic variables that have a higher effect on the response of each of them were analysed. Grape composition of both cultivars at technical maturity (considered when a probable volumetric alcoholic degree (PVAD) = 13 º was reached) was analysed during the period 2008–2020 in areas located at different elevations and related to the weather conditions recorded in those areas. The results show the effect of temperature and water availability in different periods during the growing cycle on grape composition and the potential benefits of cultivating at a higher elevation, under higher water availability. The anthocyanins were affected by the maximum temperatures recorded in the period before veraison and during ripening (period veraison to technical maturity), decreasing their concentrations with increasing temperatures. In addition, higher water availability gave rise to an increase in acidity. Graciano is shown as a variety more suitable than Tempranillo to be cultivated under warmer conditions

Projecting changes in phenology and grape composition of 'Tempranillo' and 'Grenache' varieties under climate warming in Rioja DOCa

The aim of this research was to predict the changes in vine phenology under future climate change of two red varieties, cultivated under rainfed conditions, and how grape composition can be affected. The research was conducted in Rioja Designation of Origin (DOCa), a viticultural area located in north central Spain, where red varieties represent near 90 % of the cultivated vineyards. The research focuses on 'Tempranillo' and 'Grenache', which represent about 85 % and 10 %, respectively, of cultivated red varieties in the area. The analysis included data related to vineyards located at different elevations and with different climatic conditions, recorded during the period 2008-2018. Phenological dates related to separated flowers (stage H), veraison (stage M) and maturity of the two varieties as well as the grape composition during the ripening period and at maturity were evaluated. The future scenarios were based on the predicted temperature and precipitation changes under two Representative Concentration Pathway (RCP) scenarios –RCP4.5 and RCP8.5-, which were simulated with an ensemble of models. Projections for 2050 and 2070 were made based on the observed phenological dates and the heat accumulation needed to reach each stage along the growing cycle. An advance of all phenological stages was projected, higher for veraison and maturity than for the earlier stages, and without large differences between both varieties but with differences at different elevations. Veraison is expected to be advanced up to 11 days for 2050 and up to 12 days for 2070 under the RCP4.5 scenario, while under the RCP8.5 scenario, the advance by 2070 could be up to 20 days for both varieties. For maturity, the advance could be up to 27 days for 'Tempranillo' and 25 days for 'Grenache', with differences between the cooler and the warmer areas. These changes resulted in a shortening of the periods between phenological stages, giving rise to maturity under warmer conditions. Based on the variability of grape composition observed in the warmer in relation to cooler years, and on the relationship with climate variables, a decrease in acidity as well as a reduction in the content of total anthocyanins is expected for both varieties, which may be higher for 'Grenache' than for 'Tempranillo'