Growth of ‘Thompson Seedless’ Grapevines: II. Nitrogen Distribution

Abstract

Nitrogen content and concentration were determined on field-grown ‘Thompson Seedless’ grapevines in the San Joaquin Valley of California. Individual vine replicates were harvested throughout the growing season over a 3-year period. There was a linear increase in vine N content from budbreak to 1000 growing degree days (GDDs) later. During this time, the accumulation of N was primarily in the stems and leaves. Subsequent to 1000 GDDs, the increase in vine N was due to the accumulation of N in the clusters. Throughout the season, N concentration in all vine parts decreased. The increase in cluster N content did not appear to occur at the expense of N remobilization from the vegetative structures measured in this study. On a single date, the N concentration of leaves varied throughout the canopy—the outer layer of leaves contained 3.2% N, while leaves in the interior of vine contained 2.4% N. The loss of N from the vine through leaf fall and cane pruning was about 20 and 15 g, respectively. The data were similiar from year to year with regards to both N concentration and content in leaves, stems, and clusters when plotted vs. GDDs. The approximate requirement of N for current season’s growth of ‘Thompson Seedless’ grapevines used for raisin production was 75 g/vine, or 84 kg·ha-1.

Distribution and Translocation of Nitrogen Absorbed During Late Spring by Two-Year-Old Grapevines Grown in Sand Culture

“…3e, 3f), being hydrolyzed and exported to the bunches. As expected (1,5,6,32), N migrated from leaves after harvest, with the total N showing a decline of 21% (Fig. 3d) against an even larger loss of 38% for "spring-N" (Fig.…”

“…From this stage up to the end of dormancy (30 August) the concentrations increased before starting to decrease as new growth commenced in the third season. Leaves and bunches, however, showed a decreasing trend throughout the season as was found by several other workers (4,5,13,32). The N concentration in shoots increased from the start of leaf-fall to the time of pruning, probably partly due to a concentration effect on account of reduced dry mass (Fig.…”