NITROGEN AND LIME TREATMENT EFFECTS ON THE NUTRIENT BALANCE OF APPLES

The value of a number of nitrogen and calcium sources and nutrients such as boron and zinc, were tested in an experiment on Yorking/MM.106 begun in 1972. Twenty treatments applied at preplanting were related to the uptake of nitrogen, calcium and other nutrients, nutrient balance, fruit size and corking severity.
After four years, several of the high lime treatments had increased leaf calcium levels by up to 21 per cent but produced excessive tree vigour and high N/Ca ratios in leaves and fruit flesh.
In 1976/77 nitrogen was applied only to high nitrogen treatments.
In the treatment with the highest leaf calcium (33.6 t ha^-1 lime) a decrease of 7 per cent in nitrogen leaf concentration was associated with an increase of 30 per cent in leaf calcium when comparing 1976/77 results with 1974/75. This represented a drop in the N/Ca ratio from 2.2 to 1.5 in the leaves and 22 to 20 in the fruit flesh (Table)

43.1). Where the higher lime rates were applied as coarse lime there were large increases in soil pH and leaf calcium in the fifth and sixth years.

In 1976 when the trees had a moderate crop load, the treatments which received boron had a higher boron concentration in the fruit flesh, fewer cork spots per fruit and a higher percentage first grade fruit.
In 1977 the

Symposium on Mineral Nutrition and Fruit Quality of Temperate Zone Fruit Trees

C.B. Smith, G.M. Greene

https://doi.org/10.17660/ActaHortic.1980.92.44