RAPID MONITORING OF NITROGEN IN MANGO TREES

Nitrogen (N) is an essential nutrient in mango, influencing both productivity and fruit quality.
In Australian mango orchards, tree N is traditionally assessed once a year at the dormant pre-flowering stage using laboratory analysis of leaf N. This single assessment is insufficient to determine tree N status at all stages of the annual phenological cycle.
Development of a field-based rapid N test would allow more frequent monitoring of tree N status and improved fertiliser management.
These experiments examined the accuracy and useability of several devices used in other horticultural crops to rapidly assess mango leaf N in the field; the Konica Minolta ‘SPAD-502 chlorophyll meter’, Horiba ‘Cardy Meter’ and the Merck ‘RQflex 10.’ Regression and correlation analyses were used to determine the relationship between total leaf N and the measurements from the rapid test devices.
The relationship between the chlorophyll index measured by the SPAD-502 meter and leaf N was highly significant at late fruit set (R²=0.72, n=40) and post-harvest (R²=0.81, n=40) stages and significant at the flowering stage (R²=0.51, n=40) in the cultivar ‘Kensington Pride’, indicating the device can be used to rapidly assess mango leaf N in the field.
Correlation analysis indicated the relationship between petiole sap measured with the Cardy or Merck devices and leaf N was non-significant.

IX International Mango Symposium

I.S.E. Bally, L.A. Still

rapid test, ‘Kensington Pride’, chlorophyll index

https://doi.org/10.17660/ActaHortic.2013.992.12