Modifying tree nutrition for optimal storage quality
Lime and fertiliser recommendations for apples are intended to ensure that availability and uptake of mineral nutrients do not limit growth and cropping. Soil and leaf analyses are used to determine general fertiliser requirements and to identify mineral deficiencies. The latest information on apple nutrition can be found in Section 7 (Fruit, vines and hops) of the Nutrient Management Guide (RB209).
However, it cannot be assumed that a nutrient supply that is satisfactory for tree growth and cropping necessarily produces fruit with a satisfactory storage potential and eating quality. In many cases the availability of specific minerals needs to be restricted or supplemented in order to improve storage and eating quality.
Growers are advised to analyse soils, leaves and fruits on a regular basis in order to understand the full effect of their use of lime and fertilisers in specific orchards. These different types of analyses are necessary, as often there is a lack of association between fertiliser application and nutrient uptake or a poor correlation between nutrient levels in leaves and fruits.
There are many factors other than fertiliser application that affect the levels of nutrients in the leaves and fruits. Soil type, water availability, rootstock, use of green waste mulches, pruning and cropping are some of the more important factors that influence uptake and partitioning of mineral nutrients within the tree.