Abstract
Postbloom zinc (Zn) sprays are replacing dormant and postharvest sprays as the primary means for applying Zn in commercial apple ( Malus × domestica ) orchards. We conducted a multiyear field study comparing the phytoavailability of Zn in 11 commercially available Zn spray products, plus reagent-grade Zn nitrate and a water-sprayed control, applied postbloom at identical Zn concentrations to `Golden Delicious' apple trees. Two sprays were applied per season (mid-May and mid-June), at per-spray rates of either 0.5 lb/acre in 2000 or 1.0 lb/acre in 2001 and 2002. No sprays were applied in 2003 in order to evaluate carry-over effects. The Zn sprays had no effect on fruit number, bitter pit or russeting, or on leaf green color. Zinc concentrations of detergent plus acid-washed leaves (a procedure used to remove surface residues of the Zn sprays) sampled in August and of unwashed winter buds sampled the following January were used as indices of tree Zn status. Leaf Zn concentration generally increased in the order: Zn phosphate < Zn oxide = Zn oxysulfate < chelated/organically complexed Zn ≤ Zn nitrate. There was little consistent difference among chelated and organically complexed Zn products. Leaf Zn concentration varied considerably between seasons, and was not related to Zn application rate. All of the Zn sprays increased leaf Zn concentrations to desirable levels. Because the inorganic Zn-based products typically are substantially less expensive per unit of Zn, it may be less costly and just as effective to use a higher rate of an inorganic Zn product as to use a lower rate of a more expensive chelated or organically complexed Zn product. On the other hand, use of low rates of highly phytoavailable Zn products minimizes release of the nutritionally essential but potentially ecohazardous metal into the environment. There was no detectable lasting effect of the three previous seasons of Zn sprays on leaf Zn in 2003. Similarly, there was no detectable effect in any year of the Zn spray treatments on bud Zn concentration the following winter. These results suggest that the amount of Zn supplied by the sprays at the tested rates was insufficient to promote substantial Zn accumulation within the trees, thereby validating the recommendation for annual application of Zn nutritional maintenance sprays.
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Claims 11
Claim · model-written summary
Zn sprays had no effect on fruit number, bitter pit or russeting in apple.
- Taxon
- Apple Trees
Malus domesticat0 - Treatment
- The Zn sprayse0
- Outcome
- fruit number, bitter pit or russetinge0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Zn sprays had no effect on fruit number, bitter pit or russeting, or on leaf green color”
t0“Apple Trees”
Claim · model-written summary
Zn sprays had no effect on leaf green color in apple.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- The Zn sprayse0
- Outcome
- leaf green colore0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Zn sprays had no effect on fruit number, bitter pit or russeting, or on leaf green color”
t0“Apple Trees”
Claim · model-written summary
Leaf Zn concentration generally increased in the order Zn phosphate < Zn oxide = Zn oxysulfate < chelated/organically complexed Zn <= Zn nitrate.
- Taxon
- Apple TreesMalus domesticat0
- Outcome
- Leaf Zn concentratione0
- Qualifier
- Zn phosphate < Zn oxide = Zn oxysulfate < chelated/organically complexed Zn ≤ Zn nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf Zn concentration generally increased in the order: Zn phosphate < Zn oxide = Zn oxysulfate < chelated/organically complexed Zn ≤ Zn nitrate”
t0“Apple Trees”
Claim · model-written summary
There was little consistent difference in leaf Zn among chelated and organically complexed Zn products.
- Taxon
- Apple TreesMalus domesticat0
- Outcome
- little consistent difference among chelated and organically complexed Zn productse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was little consistent difference among chelated and organically complexed Zn products”
t0“Apple Trees”
Claim · model-written summary
Leaf Zn concentration varied considerably between seasons.
- Taxon
- Apple TreesMalus domesticat0
- Outcome
- Leaf Zn concentratione0
- Qualifier
- varied considerably between seasonse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf Zn concentration varied considerably between seasons”
t0“Apple Trees”
Claim · model-written summary
Leaf Zn concentration was not related to Zn application rate.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- Zn application ratee0
- Outcome
- Zn application ratee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“was not related to Zn application rate”
t0“Apple Trees”
Claim · model-written summary
All of the Zn sprays increased leaf Zn concentrations to desirable levels compared with the water-sprayed control.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- Zn sprayse0
- Outcome
- leaf Zn concentrationse0
- Direction
- increasede0
- Comparator
- a water-sprayed controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All of the Zn sprays increased leaf Zn concentrations to desirable levels”
e1“a water-sprayed control”
t0“Apple Trees”
Claim · model-written summary
Using a higher rate of an inorganic Zn product may be less costly and just as effective as a lower rate of a more expensive chelated or organically complexed Zn product.
- Taxon
- Apple TreesMalus domesticat0
- Outcome
- less costly and just as effectivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it may be less costly and just as effective to use a higher rate of an inorganic Zn product as to use a lower rate of a more expensive chelated or organically complexed Zn product”
t0“Apple Trees”
Claim · model-written summary
There was no detectable lasting effect of the three previous seasons of Zn sprays on leaf Zn in 2003.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- three previous seasons of Zn sprayse0
- Outcome
- leaf Zne0
- Direction
- no detectable lasting effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no detectable lasting effect of the three previous seasons of Zn sprays on leaf Zn in 2003”
t0“Apple Trees”
Claim · model-written summary
There was no detectable effect in any year of the Zn spray treatments on bud Zn concentration the following winter.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- Zn spray treatmentse0
- Outcome
- bud Zn concentratione0
- Direction
- no detectable effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was no detectable effect in any year of the Zn spray treatments on bud Zn concentration the following winter”
t0“Apple Trees”
Claim · model-written summary
The authors consider that the results validate the recommendation for annual application of Zn nutritional maintenance sprays.
- Taxon
- Apple TreesMalus domesticat0
- Outcome
- annual application of Zn nutritional maintenance sprayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“thereby validating the recommendation for annual application of Zn nutritional maintenance sprays”
t0“Apple Trees”
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