Macro scale analysis of Syrah vineyards under winter growing cycles: Agronomical and ecophysiological responses

ABSTRACT: In Southeast Brazil, the change of grape harvest from wet summer to dry winter through double-pruning management has improved the quality of wines, currently denominated winter wines. In order to better understand the influences of soil, macroclimate, and vineyard management in winter wines, we investigated seven vineyards in the states of Minas Gerais (Três Corações – TC, Três Pontas – TP, Cordislândia – COR, São Sebastião do Paraíso – SSP and Andradas – AND) and São Paulo (Itobi – ITO and Espirito Santo do Pinhal – PIN) during three consecutive growing seasons. The vineyards are located in warm temperate zones and grouped in four soil types: Acrudox in TC, AND and SSP, Hapludox in TP; Hapludult in AND and PIN; Eutrudept in ITO. The high clay content (> 35 %) observed in all soil types, associated to low evapotranspiration demand, avoided the occurrence of severe water stress, as observed by the high values of leaf and stem water potential, stomatal conductance, photosynthesis, and transpiration. Differences in vigor were more related to vineyard management and did not affect grape composition. Among vineyards, parameters for berry quality from ITO, such as sugar and acidity, were more associated to high soil sand content and winter temperature. No significant differences were found in anthocyanins and total phenols of berries among vineyards, suggesting that the high thermal range and low precipitation during autumn-winter, historically observed in all municipalities, seemed to be the main factor for improvement of phenolic compounds.

摘要：在巴西东南部，通过双修剪管理将葡萄收获期从湿润夏季调整至干燥冬季，已显著提升了葡萄酒品质，这类葡萄酒目前被命名为冬酿葡萄酒（winter wines）。为深入探究土壤、大气候及葡萄园管理对冬酿葡萄酒（winter wines）的影响，我们在连续三个生长季中，对米纳斯吉拉斯州（Minas Gerais）的Três Corações（TC）、Três Pontas（TP）、Cordislândia（COR）、São Sebastião do Paraíso（SSP）与Andradas（AND），以及圣保罗州（São Paulo）的Itobi（ITO）及Espirito Santo do Pinhal（PIN）共7座葡萄园开展了调研。上述葡萄园均坐落于暖温带区域，共涵盖4类土壤类型：TC、AND与SSP地块的土壤为强风化氧化铁土（Acrudox），TP地块为暗色氧化铁土（Hapludox），AND与PIN地块为强发育老成土（Hapludult），ITO地块为肥沃薄层新成土（Eutrudept）。所有土壤类型均检测到较高的黏粒含量（>35%），加之区域蒸散需求较低，有效规避了严重水分胁迫的发生；这一结论可通过叶片与茎秆水势、气孔导度、光合速率及蒸腾速率的高观测值得到佐证。葡萄长势差异更多与葡萄园管理措施相关，并未对葡萄果实组成产生显著影响。在各调研葡萄园中，ITO地块的浆果品质参数（如糖度与酸度）与较高的土壤砂粒含量及冬季气温的关联度更高。各葡萄园的浆果花青素与总酚类物质含量未出现显著差异，这表明，所有调研县域历史上观测到的秋冬季节高温度极差与低降水量，或是酚类物质品质提升的核心影响因素。