Abstract

The levels of N, P, K, Ca and Mg in the various organs of a raspberry plant were determined at intervals from the beginning of April to mid-August. Expressed as percentage dry weight, nutrient levels were generally highest in the fruits and leaves, at intermediate levels in prinocane stems and fruiting laterals and at low levels in the fruiting cane stem. The concentration of most minerals fell rapidly over the growing season in all components except the fruiting cane stem. Leaf levels of N and P were significantly higher in primocane leaves throughout the sampling period.
The total weight of each nutrient in the plant usually showed an increase over time, with fruiting cane having as high a total nutrient demand as primocane in the period up to the end of fruiting. Apparent falls in the total weight of fruiting cane leaf N and Mg at the time of fruit development were probably due partly to leaf fall but there may have been some transfer of the nutrients to the fruit. At the end of the fruiting period the accumulated mineral contents of the fruit, expressed as a percentage of total above-ground plant content, were: N - 33%, P - 40%, K - 42%, Ca - 15% and Mg - 21%.