Abstract
One of the primary reasons for the slow adoption of mechanical harvesting by Florida citrus growers is the physical injuries associated with it, including loss of leaves, twigs, flowers, and young fruits, limb breakage, and injuries to the bark and root. However, it has been shown that well-managed trees are capable of tolerating defoliation, limb loss, and root and bark injury caused by mechanical harvesting. Irrigation management is one of the most crucial factors that influence citrus tree health. A multiple-year field study was conducted on ‘Valencia’ sweet orange trees in a commercial citrus grove near Immokalee, FL, to determine the effect of initial tree canopy density and short-term drought stress on tree health, water uptake, and productivity of mechanically harvested trees. Three blocks were based on canopy density and overall appearance and indicated as low, moderate, and high canopy density. The experiment was laid in a split-plot design with four replications of six-tree plots of hand-harvested or mechanically harvested trees, taking drought stress or full irrigation as main treatments. The experimental design was repeated with trees in each plot of one of the three canopy density categories. After harvest, each six-tree plot was split into two three-tree subplots, where one subplot was drought-stressed and the other was fully irrigated. Harvesting was conducted in the Spring of 2010, 2011, and 2012 with the same experimental design and data collection procedures. The effects of short-term drought on water use and stem water potential were masked by heavy rains in Spring 2010 and thus no differences in the irrigation treatments were observed. In 2011 and 2012, stem water potential was unaffected by harvesting method. Water use was unaffected by harvesting method across the 3 years. Drought stress significantly increased pull force required to remove fruit and stem water potential after harvest. Although mechanically harvested trees lost leaf mass, with no rain before harvest, results from Spring 2011 and 2012 indicated that short-term drought stress had no effect on citrus leaf area irrespective of harvest method. Drought stress significantly increased fruit detachment force in low and moderate density but not in high-density trees resulting in increased force required to remove fruit from trees with moderate- to low-density canopies. Yield increased from 2010 to 2011 for mechanically harvested trees compared with hand-harvested for low-canopy density trees by 17% and moderate-canopy density trees by 8%, whereas high-density plots indicated similar yield after mechanical harvesting. Comparatively, yield in 2012 decreased in the low and moderate densities compared with yield in 2011 but increased in the high density by 14% and 53% in hand- and machine-harvested trees, respectively. Despite finding 2- to 3-fold more debris in the mechanically harvested trees than the hand-harvested trees, yields and other measured parameters were unaffected suggesting that mechanical harvesting of citrus trees did not have an adverse effect on growth and production of well-watered citrus trees.
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Claims 17
Claim · model-written summary
Heavy rain masked drought effects on water use and stem water potential in 2010.
- Taxon
- Sweet Orange
Citrus sinensist0 - Outcome
- water use and stem water potentiale0
- Qualifier
- masked by heavy rains in Spring 2010e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects of short-term drought on water use and stem water potential were masked by heavy rains in Spring 2010”
t0“Sweet Orange”
Claim · model-written summary
Harvest method left stem water potential unaffected in 2011 and 2012.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- harvesting methode0
- Outcome
- stem water potentiale0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 2011 and 2012, stem water potential was unaffected by harvesting method”
t0“Sweet Orange”
Claim · model-written summary
Harvest method left water use unaffected across three years.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- harvesting methode0
- Outcome
- Water usee0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water use was unaffected by harvesting method across the 3 years”
t0“Sweet Orange”
Claim · model-written summary
Drought increased fruit pull force.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- Drought stresse0
- Outcome
- pull force required to remove fruite0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress significantly increased pull force required to remove fruit”
t0“Sweet Orange”
Claim · model-written summary
Drought increased postharvest stem water potential.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- Drought stresse0
- Outcome
- stem water potentiale0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress significantly increased pull force required to remove fruit and stem water potential after harvest”
t0“Sweet Orange”
Claim · model-written summary
Mechanical harvesting caused leaf mass loss.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- mechanically harvestede0
- Outcome
- leaf masse0
- Direction
- loste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mechanically harvested trees lost leaf mass”
t0“Sweet Orange”
Claim · model-written summary
Short drought did not affect leaf area in 2011 and 2012.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- short-term drought stresse0
- Outcome
- citrus leaf areae0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“short-term drought stress had no effect on citrus leaf area irrespective of harvest method”
t0“Sweet Orange”
Claim · model-written summary
Drought increased fruit detachment force in low and moderate canopy density trees.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- Drought stresse0
- Outcome
- fruit detachment forcee0
- Direction
- increasede0
- Qualifier
- low and moderate densitye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress significantly increased fruit detachment force in low and moderate density”
t0“Sweet Orange”
Claim · model-written summary
Drought did not increase detachment force in high density trees.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- Short-term Drought Stresst0
- Outcome
- Tree Healtht0
- Qualifier
- high-density treese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but not in high-density trees”
t0“Short-term Drought Stress and Mechanical Harvesting on Sweet Orange Tree Health”
Claim · model-written summary
Mechanical harvest raised 2011 yield 17% in low canopy density trees relative to hand harvest.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- mechanically harvestede0
- Outcome
- Yielde0
- Direction
- increasede0
- Value
- 17%e0
- Qualifier
- low-canopy density treese0
- Comparator
- hand-harvestede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield increased from 2010 to 2011 for mechanically harvested trees compared with hand-harvested for low-canopy density trees by 17%”
t0“Sweet Orange”
Claim · model-written summary
Mechanical harvest raised 2011 yield 8% in moderate canopy density trees relative to hand harvest.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- Mechanical Harvestingt0
- Outcome
- Yieldt0
- Value
- 8%e0
- Qualifier
- moderate-canopy density treese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“moderate-canopy density trees by 8%”
t0“Mechanical Harvesting on Sweet Orange Tree Health, Water Uptake, and Yield”
Claim · model-written summary
High density plots had similar yield after mechanical harvest.
- Taxon
- Sweet OrangeCitrus sinensist0
- Outcome
- yielde0
- Direction
- similare0
- Qualifier
- high-density plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high-density plots indicated similar yield after mechanical harvesting”
t0“Sweet Orange”
Claim · model-written summary
In 2012 low and moderate density yields decreased relative to 2011.
- Taxon
- Sweet OrangeCitrus sinensist0
- Outcome
- yielde0
- Direction
- decreasede0
- Qualifier
- low and moderate densitiese0
- Comparator
- yield in 2011e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“yield in 2012 decreased in the low and moderate densities compared with yield in 2011”
t0“Sweet Orange”
Claim · model-written summary
High density hand harvested yield increased 14% in 2012.
- Taxon
- Sweet OrangeCitrus sinensist0
- Outcome
- Yieldt0
- Direction
- increasede0
- Value
- 14%e0
- Qualifier
- hand- and machine-harvested treese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased in the high density by 14% and 53% in hand- and machine-harvested trees, respectively”
t0“Sweet Orange Tree Health, Water Uptake, and Yield”
Claim · model-written summary
High density machine harvested yield increased 53% in 2012.
- Taxon
- Sweet OrangeCitrus sinensist0
- Outcome
- Yieldt0
- Direction
- increasede0
- Value
- 53%e0
- Qualifier
- machine-harvested treese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased in the high density by 14% and 53% in hand- and machine-harvested trees, respectively”
t0“Sweet Orange Tree Health, Water Uptake, and Yield”
Claim · model-written summary
Mechanical harvesting produced two to three times more debris than hand harvesting.
- Taxon
- Sweet OrangeCitrus sinensist0
- Treatment
- mechanically harvestede0
- Outcome
- debrise0
- Direction
- moree0
- Value
- 2- to 3-folde0
- Comparator
- hand-harvestede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“2- to 3-fold more debris in the mechanically harvested trees than the hand-harvested trees”
t0“Sweet Orange”
Claim · model-written summary
Authors concluded mechanical harvest did not adversely affect well watered citrus growth and production.
- Treatment
- mechanical harvestinge0
- Outcome
- growth and productione0
- Direction
- did not have an adverse effecte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mechanical harvesting of citrus trees did not have an adverse effect on growth and production of well-watered citrus trees”
The same questions in other papers
drought · growth · Citrus sinensis (sweet orange)Positive and negative results
4 papers in the same direction as this paper · 1 in the opposite direction
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See all 6 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.