Abstract
Foliar fertilization reduces nutrient accumulation in soil, run-off and groundwater, where they contribute to salinity, eutrophication or nitrate contamination, with negative consequences to humans and the environment. Soil-applied fertilizers should be replaced in part with foliar-applied fertilizers. Foliar fertilizers can meet the crop's nutrient demand when soil temperature, moisture, pH, or salinity renders soil-applied fertilizers ineffective. Applying nutrients directly to leaves ensures that the plant's photosynthetic machinery is not compromised by low availability of an essential nutrient. Foliar-applied phloem-mobile nutrients are translocated to all plant parts, even feeder roots. However, not all nutrients are taken up through leaves and, even if taken up, some nutrients are not phloem mobile. Foliar fertilizer rates are typically lower than soil fertilizer rates, but application can be more costly. The goal of our research is to properly time the application of foliar fertilizers at specific stages of tree phenology, when nutrient demand is likely high, to increase yield, fruit size or quality, such that foliar fertilization results in a net increase in grower income even when the tree is not nutrient deficient by standard leaf analysis. A single foliar application of zinc sulphate to Citrus sinensis, 'Washington' navel orange, at 10% anthesis significantly increased fruit set through harvest in January, without impact on fruit size or quality. Later applications reduced fruit set. Winter (December) prebloom foliar application of low-biuret urea to C. reticulata, 'Nules' Clementine mandarin, increased 2-year cumulative yield of commercially valuable fruit (transverse diameter 63.51-69.85 mm) as both kg and number of fruit per tree with no effect on total yield or fruit quality. Earlier or later applications were without effect. Foliar application of potassium phosphite to Persea americana, 'Hass', at the cauliflower stage of inflorescence development significantly increased 3-year cumulative yield (kg and number of fruit per tree) of commercially valuable fruit (178-325 g per fruit) compared to trees receiving foliar- or soil-applied potassium phosphate. All cases resulted in a net increase in grower income.
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Claims 8
Claim · model-written summary
Zinc sulphate at 10% anthesis significantly increased Washington navel orange fruit set through January harvest.
- Taxon
- Citrus sinensis
Citrus sinensise0 - Material
- 'Washington' navel orangee0
- Organ / stage
- 10% anthesise0
- Treatment
- A single foliar application of zinc sulphatee0
- Outcome
- fruit sete0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A single foliar application of zinc sulphate to Citrus sinensis, 'Washington' navel orange, at 10% anthesis significantly increased fruit set through harvest in January”
Claim · model-written summary
The orange zinc application did not affect fruit size or quality.
- Taxon
- Citrus sinensisCitrus sinensise0
- Material
- 'Washington' navel orangee0
- Treatment
- A single foliar application of zinc sulphatee0
- Outcome
- fruit size or qualitye0
- Direction
- without impacte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A single foliar application of zinc sulphate to Citrus sinensis, 'Washington' navel orange, at 10% anthesis significantly increased fruit set through harvest in January, without impact on fruit size or quality”
Claim · model-written summary
Later zinc applications reduced orange fruit set.
- Taxon
- Citrus sinensisCitrus sinensise0
- Treatment
- Later applicationse0
- Outcome
- fruit sete0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A single foliar application of zinc sulphate to Citrus sinensis, 'Washington' navel orange, at 10% anthesis significantly increased fruit set through harvest in January, without impact on fruit size or quality. Later applications reduced fruit set”
Claim · model-written summary
Winter prebloom low-biuret urea increased commercially valuable Clementine mandarin fruit yield in kg and number over two years.
- Taxon
- C. reticulata
.jpg?width=60)
Citrus reticulatae0 - Material
- 'Nules' Clementine mandarine0
- Treatment
- Winter (December) prebloom foliar application of low-biuret ureae0
- Outcome
- 2-year cumulative yield of commercially valuable fruite0
- Direction
- increasede0
- Qualifier
- transverse diameter 63.51-69.85 mme0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Winter (December) prebloom foliar application of low-biuret urea to C. reticulata, 'Nules' Clementine mandarin, increased 2-year cumulative yield of commercially valuable fruit (transverse diameter 63.51-69.85 mm) as both kg and number of fruit per tree”
Claim · model-written summary
The winter prebloom urea application had no effect on total mandarin yield or fruit quality.
- Taxon
- C. reticulataCitrus reticulatae0
- Treatment
- Winter (December) prebloom foliar application of low-biuret ureae0
- Outcome
- total yield or fruit qualitye0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Winter (December) prebloom foliar application of low-biuret urea to C. reticulata, 'Nules' Clementine mandarin, increased 2-year cumulative yield of commercially valuable fruit (transverse diameter 63.51-69.85 mm) as both kg and number of fruit per tree with no effect on total yield or fruit quality”
Claim · model-written summary
Earlier or later urea applications had no effect on mandarin yield.
- Taxon
- C. reticulataCitrus reticulatae0
- Treatment
- Earlier or later applicationse0
- Outcome
- without effecte0
- Direction
- without effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Winter (December) prebloom foliar application of low-biuret urea to C. reticulata, 'Nules' Clementine mandarin, increased 2-year cumulative yield of commercially valuable fruit (transverse diameter 63.51-69.85 mm) as both kg and number of fruit per tree with no effect on total yield or fruit quality. Earlier or later applications were without effect”
Claim · model-written summary
Potassium phosphite at the cauliflower inflorescence stage significantly increased three-year commercially valuable Hass avocado yield against potassium phosphate.
- Taxon
- Persea americana
Persea americanae0 - Material
- 'Hass'e0
- Organ / stage
- cauliflower stage of inflorescence developmente0
- Treatment
- Foliar application of potassium phosphitee0
- Outcome
- 3-year cumulative yield (kg and number of fruit per tree) of commercially valuable fruite0
- Direction
- increasede0
- Qualifier
- 178-325 g per fruite0
- Comparator
- trees receiving foliar- or soil-applied potassium phosphatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar application of potassium phosphite to Persea americana, 'Hass', at the cauliflower stage of inflorescence development significantly increased 3-year cumulative yield (kg and number of fruit per tree) of commercially valuable fruit (178-325 g per fruit) compared to trees receiving foliar- or soil-applied potassium phosphate”
Claim · model-written summary
All three foliar fertilization cases increased grower income.
Not reportedTaxon
Verbatim
e0“All cases resulted in a net increase in grower income”
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See all 17 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.