Abstract
The commercial blueberry industry in Florida has expanded significantly in both acreage and value in the past several years. The southern highbush blueberry (SHB, Vaccinium corymbosum L. interspecific hybrid) is the major blueberry type grown in Florida. The nitrogen (N) demand of young SHB differs from the northern highbush blueberry (NHB, V. corymbosum L.) and from mature blueberry plants. The objective of this study was to optimize fertigated N rates for the growth and yield of young SHB plants. One-year-old ‘Emerald’ and ‘Farthing’ plants were fertilized with 32N-0P-0K through drip irrigation at annual rates of 0, 42, 84, 168, and 336 kg N ha−1. Soil nitrate levels at multiple depths were measured along with leaf nutrient concentration, percent canopy ground cover, fruit yield and fruit quality. The results indicated that N rates had no significant effect on leaf nutrient concentrations. Greater N rates advanced bloom and harvest, increased percentage of ground cover (an indicator of canopy size), fruit yield and berry numbers per plant, but decreased mean berry diameter and weight. The soil nitrate results from both ‘Emerald’ and ‘Farthing’ revealed that the 336 kg N ha−1 treatment had a significantly greater risk for nitrate leaching than the lower N treatments in spring. The effect of N rates on fruit quality varied with cultivar and harvest season. The linear plateau regression of fruit yield and N rates indicated that the maximum yield reached at the annual N fertigation rate of 222 kg ha−1 for ‘Emerald’ and 206 kg ha−1 for ‘Farthing’.
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Claims 8
Claim · model-written summary
Nitrogen rates had no significant effect on leaf nutrient concentrations.
- Taxon
- southern highbush blueberryt0
- Treatment
- N ratese0
- Outcome
- leaf nutrient concentrationse0
- Direction
- no significant effecte0
Not reportedComparator
Verbatim
e0“N rates had no significant effect on leaf nutrient concentrations”
t0“southern highbush blueberry”
Claim · model-written summary
Greater nitrogen rates advanced bloom and harvest.
- Taxon
- southern highbush blueberryt0
- Treatment
- Greater N ratese0
- Outcome
- bloom and harveste0
- Direction
- advancede0
Not reportedComparator
Verbatim
e0“Greater N rates advanced bloom and harvest”
t0“southern highbush blueberry”
Claim · model-written summary
Greater nitrogen rates increased canopy ground cover, fruit yield and berry number.
- Taxon
- southern highbush blueberryt0
- Treatment
- Greater N ratest1
- Outcome
- percentage of ground cover (an indicator of canopy size), fruit yield and berry numbers per plante0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“increased percentage of ground cover (an indicator of canopy size), fruit yield and berry numbers per plant”
t0“southern highbush blueberry”
t1“Greater N rates advanced bloom and harvest”
Claim · model-written summary
Greater nitrogen rates decreased mean berry diameter and weight.
- Taxon
- southern highbush blueberryt0
- Treatment
- Greater N ratest1
- Outcome
- mean berry diameter and weighte0
- Direction
- decreasede0
Not reportedComparator
Verbatim
e0“but decreased mean berry diameter and weight”
t0“southern highbush blueberry”
t1“Greater N rates advanced bloom and harvest”
Claim · model-written summary
The 336 kg N ha−1 treatment increased spring nitrate leaching risk relative to lower treatments.
Verbatim
e0“the 336 kg N ha−1 treatment had a significantly greater risk for nitrate leaching than the lower N treatments in spring”
t0“southern highbush blueberry”
Claim · model-written summary
Nitrogen effects on fruit quality varied by cultivar and harvest season.
- Taxon
- southern highbush blueberryt0
- Treatment
- N ratese0
- Outcome
- fruit qualitye0
- Qualifier
- cultivar and harvest seasone0
Not reportedDirection
Verbatim
e0“The effect of N rates on fruit quality varied with cultivar and harvest season”
t0“southern highbush blueberry”
Claim · model-written summary
Emerald maximum yield was reached at 222 kg ha−1 annual nitrogen fertigation.
Verbatim
e0“maximum yield reached at the annual N fertigation rate of 222 kg ha−1 for ‘Emerald’”
t0“southern highbush blueberry”
Claim · model-written summary
Farthing maximum yield was reached at 206 kg ha−1 annual nitrogen fertigation.
Verbatim
e0“and 206 kg ha−1 for ‘Farthing’”
t0“southern highbush blueberry”
t1“maximum yield reached at the annual N fertigation rate of 222 kg ha−1 for ‘Emerald’”
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