Mineral status of kiwiberry

Kiwiberry [Actinidia arguta (Siebold et Zucc.) Planch. ex Miq.] is – just like the green (Actinidia chinensis var. deliciosa) and yellow (A. chinensis var. chinensis) kiwifruit – a fast-growing, deciduous climbing plant that requires adequate fertilizer management for optimum orchard production. However, compared with kiwifruit, very little is known about the fertilization needs of this crop. Since kiwiberry is gaining importance worldwide, a project was started at four mature orchards in Belgium and the Netherlands with a focus on the mineral status of kiwiberry plants. During two growing seasons, visual deficiency symptoms were recorded and the mineral composition of the first basal leaves on fruiting canes was monitored for three cultivars, ‘Geneva’, ‘Weiki’ and ‘Issai’. We then assessed how these data correlated with each other and whether they were related to soil parameters. Additionally, the mineral composition of the fruits was determined and linked to fruit quality, which was evaluated by storage tests. Sufficiency ranges were set up for kiwiberry leaf composition based on hundreds of foliar analyses for three different timeframes during the growing season: pre-flowering, from flowering until 50 days after full flowering, and from 50 days after full flowering until harvest. The data showed that, in comparison with green and yellow kiwifruit, kiwiberry has a tendency to have higher B, higher Cl, and lower Zn levels in its leaves. Moreover, kiwiberry appeared to be very sensitive to Mn deficiency. Clear varietal differences were observed in the leaves for Mg and P. Sufficiency ranges are important to evaluate foliar analyses and, by consequence, the mineral status of kiwiberry orchards. Although the mineral fruit composition at harvest varied significantly depending on the location, Ca consistently played a key role in the storability of the berries. However, besides Ca, the ratios with, inter alia, K, Mg and N were also important.