Yield and must composition of ‘cabernet sauvignon’ grapevines subjected to nitrogen application in soil with high organic matter content

Abstract

It is common for vineyards in regions of high altitude to have high organic matter content in soil. Furthermore, reduced mineralization of organic matter and decomposing residues is expected because of the low temperatures. Thus, soils may not provide enough mineral nitrogen (N) to meet the needs of the grapevines and so the application of N sources is necessary, but may affect yield and must composition. The study aimed to evaluate yield and must composition of grapevines subjected to N application in soil with high organic matter content and the relationship with temperature and rainfall. The study was conducted in crops seasons 2011/12, 2012/13 and 2013/14 in a vineyard located in the city of Água Doce, state of Santa Catarina, southern Brazil. The treatments consisted of N doses (0, 20, 40, 80 and 120 kg N ha–1) supplied via urea. Leaves opposite to the cluster were collected at full flowering and at veraison. Afterwards, the leaves were dried, ground and submitted to N analysis. Parameters of yield and must composition were evaluated. The dose of maximum technical efficiency in Cabernet Sauvignon grapevines was reached with 46 kg N ha–1 year–1 in crop season 2012/13. Leaf N content was a sensitive parameter to the application of N doses in the soil and underwent seasonal variation in relation to rainfall distribution. The N doses reduced total soluble solids (TSS) contents in the must. Based on principal component analysis, we found a correlation between total N content in leaf and accumulated rainfall, as well as between yield and temperature.