Seasonal variation in mineral composition of fine roots from field-grown kiwifruit vines

Abstract

Seasonal variation in the concentration of macronutrients and micronutrients in fine roots (<2 mm diameter) of mature kiwifruit (Actinidia deliciosa var. deliciosa) vines were sampled regularly over 1 year. For the majority of elements, concentrations exhibited a sinusoidal pattern of change, with a seasonal minimum 1–13 weeks after fruitset, and a seasonal maximum, within 12 weeks of budbreak. Concentrations thus declined from around budbreak until after fruitset, thee began rising again before harvest, and into winter. Exceptions were calcium and iron, which fluctuated randomly about a constant value throughout the season, and magnesium and boron, which had two maxima (instead of one) between harvest and budbreak. Measurements were compared with those from other woody tree crops, and the potential for the fine root system to supply nutrient to new season's growth is discussed.

Keywords:

• Actinidia deliciosa
• kiwifruit
• nutrient concentrations
• seasonal change
• roots