Seasonal dynamics of biomass and mineral nutrient partitioning in mature kiwifruit vines.
Clark, C. J.; Smith, G. S.;
Annals of Botany Year: 1992 Vol: 70 Issue: 3 Pages: 229-237 Ref: 25 ref.
1992
บทคัดย่อ
The accumulation of DM plus major and trace elements by various components of 6-year-old, field-grown kiwifruit vines (cv. Hayward) was recorded over one season. Twenty vines were harvested periodically throughout the year and separated into perennial components (roots <20 mm diameter, structural roots, stump, stem, cordon, one-year-old fruiting wood) and current season's growth (non-fruiting shoots, laterals on fruiting wood, leaves and fruits). There was minimal seasonal variation (CVs <7%) in biomass change in perennial components of the vine. Concentrations in these components either fluctuated about a constant value, or indicated a strong seasonal dependence. Changes in biomass and nutrient concentrations in current season's growth, however, were very regular. Prior to budbreak, below-ground components contained between 48 and 81% of the total content of each element. Roots <20 mm in diameter contained more total nutrient than any other perennial component of the vine during the season, with the exception of Zn and Cu, which were concentrated in the cordon. There was consistent accumulation of each nutrient from budbreak until harvest. Rates of greatest uptake occurred in the month following budbreak, or in the 3 weeks after anthesis. Between dormancy and harvest, whole-vine contents increased for all nutrients. Increases in Fe, Mg, P, S and Zn ranged from 21% (Zn) to 88% (Mg), and in B, Ca, Cl, Cu, K, N and Mn from 109% (Cu) to 302% (Cl). Despite the large requirements of the current season's growth, net changes in the seasonal content of perennial components were relatively small. Cu, Mg, P, N and Cl were the elements in which perennial reserves were utilized to the greatest extent to meet transient deficits between nutrient demand for the current season's growth, and that recently taken up from soil. Generally, reserves utilized during the period of vegetative growth were replaced by harvest-time. These observations, based on application of a single fertilizer dressing before budbreak, suggest the vine maintains satisfactory nutrient reserves without the need for late-season or postharvest applications of fertilizer to supplement these reserves, as occurs with some other fruiting crops.