Articles
Nutrient status of apple trees impacted by bushfires: does nature of fire affect tree nutrition?
Article number
1432_18
Pages
131 – 138
Language
English
Abstract
Bushfire incursion into orchards is threatening horticultural fruit tree production because of the adverse effects of fire on tree physiology and functioning.
Factors such as prevailing weather and orchard conditions, and tree inherent characteristics, could enhance fire destructive ability leading to greater effects on trees.
This study investigated the nutrient status of apple trees in Australian orchards exposed to two unique fire types, during the 2019-2020 Australian bushfires.
The assessment was carried out on ‘Royal Gala’/M26 and ‘Rosy Glow’/M9 apple trees affected by smoldering and radiant fires, respectively.
For both sites, fire effects on tree nutrition were assessed for the immediate three seasons after bushfires, through the analysis of leaves from trees in the four established impact levels.
In the smoldering fire site, mean summer K and P leaf values across three seasons, were higher and significantly different (p<0.05) from the standard nutrient values (SNVs) except in extremely impacted trees.
Mean N, Ca and Mg leaf contents of smoldered trees were lower than SNVs.
In the blowtorch site mean K leaf nutrient value across the three seasons was significantly lower than SNV in slightly, moderately, and severely impacted trees.
Extremely impacted trees had lower mean K value which was not significantly different (p>0.05) from the SNV. Apart from N, other analyzed nutrients (P, Ca and Mg), in the blowtorch site, were within or above the standard nutrient range.
Highest bushfire impact on nutrient was observed in the smoldering fire site as nutrient status was constantly lowest in extremely impacted trees, for all analyzed macronutrients.
These findings show that smoldering fire could elicit greater negative effects on tree nutrition in the few seasons after fruit tree damage by bushfires.
Management strategies for reducing orchard vegetation cover within interrow must be developed prior to fire seasons to protect tree damage and the potential effects on nutrition.
Factors such as prevailing weather and orchard conditions, and tree inherent characteristics, could enhance fire destructive ability leading to greater effects on trees.
This study investigated the nutrient status of apple trees in Australian orchards exposed to two unique fire types, during the 2019-2020 Australian bushfires.
The assessment was carried out on ‘Royal Gala’/M26 and ‘Rosy Glow’/M9 apple trees affected by smoldering and radiant fires, respectively.
For both sites, fire effects on tree nutrition were assessed for the immediate three seasons after bushfires, through the analysis of leaves from trees in the four established impact levels.
In the smoldering fire site, mean summer K and P leaf values across three seasons, were higher and significantly different (p<0.05) from the standard nutrient values (SNVs) except in extremely impacted trees.
Mean N, Ca and Mg leaf contents of smoldered trees were lower than SNVs.
In the blowtorch site mean K leaf nutrient value across the three seasons was significantly lower than SNV in slightly, moderately, and severely impacted trees.
Extremely impacted trees had lower mean K value which was not significantly different (p>0.05) from the SNV. Apart from N, other analyzed nutrients (P, Ca and Mg), in the blowtorch site, were within or above the standard nutrient range.
Highest bushfire impact on nutrient was observed in the smoldering fire site as nutrient status was constantly lowest in extremely impacted trees, for all analyzed macronutrients.
These findings show that smoldering fire could elicit greater negative effects on tree nutrition in the few seasons after fruit tree damage by bushfires.
Management strategies for reducing orchard vegetation cover within interrow must be developed prior to fire seasons to protect tree damage and the potential effects on nutrition.
Authors
O. Idowu, T. Pitt, K. Dodds, J. Golding, J. Fearnley, P. Petrie, B. Holzapfel
Keywords
radiant fires, smoldering fires, fruit tree, macronutrients, orchard productivity
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