Articles
COMBINING LOW BIURET UREA WITH FOLIAR ZINC SULFATE SPRAYS TO FERTILIZE PEACH AND NECTARINE TREES IN THE FALL
Article number
564_38
Pages
321 – 327
Language
English
Abstract
It has been demonstrated that nitrogen (N) applied as foliar urea to peach and nectarine trees in the fall is readily taken up by leaves and distributed throughout the organs of the tree including the roots.
Therefore, this method of fertilization could be a useful tool to supplement soil-applied fertilization and thus help reduce the potential for excess nitrates in the environment.
Two experiments were conducted to study the horticultural aspects and the practical feasibility of this practice.
The first trial consisted of nine combinations of foliar and soil-applied fertilizers imposed in a commercial orchard of ‘Queencrest’ peach trees over two years.
The treatments that included foliar urea to supply part or all of the N fertilizer were equivalent to the soil-fertilized control in fruit soluble solids content, flower density, fruit set and fruit defects.
Therefore, there appeared to be no negative horticultural effects of fall foliar urea treatments.
The second trial was conducted in a commercial orchard of ‘Summer Beaut’ nectarine and ‘David Sun’ peach.
The objective of this experiment was to study the feasibility of combining foliar urea with zinc sulfate sprays that are co only applied commercially to California stone fruit orchards in October.
Eight different combinations were tested.
Foliar urea substantially increased leaf N concentration the day after application.
However, the amount of N that moved out of the leaves before leaf senescence was the same as the unsprayed control.
When urea was combined with zinc sulfate, there was a significantly greater decrease in leaf N suggesting zinc helps mobilize N out of the leaves.
Zinc sulfate caused earlier defoliation compared to the unsprayed control and the addition of urea advanced it further by about a week in one of two years.
However, none of the combinations caused any reduction in flowering compared to the unsprayed control.
Therefore, this method of fertilization could be a useful tool to supplement soil-applied fertilization and thus help reduce the potential for excess nitrates in the environment.
Two experiments were conducted to study the horticultural aspects and the practical feasibility of this practice.
The first trial consisted of nine combinations of foliar and soil-applied fertilizers imposed in a commercial orchard of ‘Queencrest’ peach trees over two years.
The treatments that included foliar urea to supply part or all of the N fertilizer were equivalent to the soil-fertilized control in fruit soluble solids content, flower density, fruit set and fruit defects.
Therefore, there appeared to be no negative horticultural effects of fall foliar urea treatments.
The second trial was conducted in a commercial orchard of ‘Summer Beaut’ nectarine and ‘David Sun’ peach.
The objective of this experiment was to study the feasibility of combining foliar urea with zinc sulfate sprays that are co only applied commercially to California stone fruit orchards in October.
Eight different combinations were tested.
Foliar urea substantially increased leaf N concentration the day after application.
However, the amount of N that moved out of the leaves before leaf senescence was the same as the unsprayed control.
When urea was combined with zinc sulfate, there was a significantly greater decrease in leaf N suggesting zinc helps mobilize N out of the leaves.
Zinc sulfate caused earlier defoliation compared to the unsprayed control and the addition of urea advanced it further by about a week in one of two years.
However, none of the combinations caused any reduction in flowering compared to the unsprayed control.
Authors
R.S. Johnson, H.L. Amdris
Keywords
Foliar urea, Prunus persica, nitrogen use efficiency, Quit quality
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