Seasonal uptake and partitioning of macronutrients in mature 'concord' grape.

ADDITIONAL INDEX WORDS. calcium, magnesium, nitrogen, phosphorus, potassium, Vitis labruscana ABSTRACT. Understanding how grape (Vitis L.) vines store nutrients in permanent tissues, how much nutrient vines take up from the soil, and how nutrients are partitioned and redistributed throughout the plant is critical to the development of sound nutrient management practices. This study investigated the seasonal patterns of macronutrient uptake and redistribution in whole 'Concord' grape (Vitis labruscana Bailey) vines. The study was conducted in a 42- year-old own-rooted 'Concord' vineyard. The site was a furrow-irrigated fine sandy loam. In 2006 and 2007, four vines were excavated at winter pruning, budbreak, three- to four-leaf stage, bloom, veraison, harvest, and postharvest. Each vine was separated into different organs, dried, and weighed to determine biomass, and then ground and analyzed for C, N, P, K, Ca, and Mg. The results showed that the seasonal dynamics of nutrient contents shared a consistent pattern: translocation of nutrients from woody tissues to actively growing organs at the beginning of the season; nutrient uptake from bloom to veraison (P and Mg in 2006), bloom to harvest (N, P, K, and Ca), or veraison to harvest (P and Mg in 2007); and nutrient movement to woody tissues occurring after veraison until leaf fall with no further nutrient uptake. There was a very high accumulation of Ca in permanent structures of the vine, reflecting the high Ca and CaCO3 found in the soils of the region. As a result, the vines had a higher Ca content than all other nutrients throughout the growing season, which is different from findings in other growing areas. Grape is a perennial crop in which the mineral nutrient concentration changes throughout the growing season. Not only is a portion of the vine's mineral nutrients taken up from the soil each year, the other portion is redistributed throughout the plant from woody and root tissues that function as storage organs. Most studies report that grapevines take up the majority of the N between bloom and veraison (Araujo and Williams, 1988; Bates et al., 2002; Hanson and Howell, 1995; Lohnertz, 1991; Mullins et al., 1992; Williams and Biscay, 1991). However, Conradie (1980, 1981, 1986) reported substantial N uptake after harvest in potted 'Chenin Blanc' grown in the South Africa. He reported that N uptake during the postharvest period was 27% and 37% of the total annual N uptake (Conradie, 1980, 1986, respectively) and provided 60% of the stored N for the next season (Conradie, 1992). Potassium uptake in whole vines was examined in several studies (Conradie, 1981; Schreiner et al., 2006; Williams and Biscay, 1991). These studies showed that the bulk of K uptake occurred between bloom and veraison. Of the three studies, only Conradie (1981) in South Africa and Schreiner et al. (2006) in an Oregon field study examined P, Ca, and Mg uptake in their whole-vine studies. Their results agreed that the time of maximum Ca and Mg uptake was between bloom and veraison. However, the Oregon study on 23-year-old 'Pinot Noir' showed that P uptake occurred predominantly before bloom, while the South African study on 2-year-old 'Chenin Blanc'/99 Richter