Abstract
Abstract We are in the process of developing N best management practices for citrus in sandy Entisols to increase N uptake efficiency and to minimize NO 3 leaching below the rooting depth. We evaluated the effects of N sources as either dry granular form (DGF), fertigation (FRT), or controlled‐release fertilizer (CRF), and rates (56–280 kg N ha ‐1 yr ‐1 ) with optimum irrigation management on: (i) the fruit yield and quality and leaf nutrient concentrations of bearing ‘Hamlin’ orange [ Citrus sinensis (L.) Osbeck] trees on ‘Cleopatra’ mandarin ( Citrus reticulata Blanco) rootstock (planted in 1974) grown in a Tavares fine sand (hyperthermic, uncoated Typic Quartzipsamments) and (ii) changes in NO 3 ‐N status in soil solution sampled from the vadose zone both within and below the root zone. For the DGF and FRT sources, 3‐yr mean fruit yield increased with an increase in N rates in the range of 112 to 224 kg ha ‐1 yr ‐1 . For further increase in N rate, the fruit yield showed a diminishing response, which was quite marked for the DGF. The N requirements for 1 Mg of fruit, mean across all N rates, were 1.79, 2.58, and 2.75 kg N for the CRF, FRT, and DGF sources, respectively. Leaf N concentrations were maintained within the optimal range (25–27 g kg ‐1 ) at N rates ≥168 kg ha ‐1 yr ‐1 , regardless of source of N. Various N rates and sources did not significantly affect the fruit size, nor juice quality parameters. The improved management of irrigation and fertilizer placement and timing of application contributed to minimized leaching of NO 3 ‐N below the root zone.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 8
Claim · model-written summary
DGF and FRT fruit yield increased as N rate rose from 112 to 224 kg ha ‐1 yr ‐1.
- Treatment
- N rates in the range of 112 to 224 kg ha ‐1 yr ‐1e0
- Outcome
- fruit yielde0
- Direction
- increasede0
- Qualifier
- DGF and FRT sourcese0
CitrusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For the DGF and FRT sources, 3‐yr mean fruit yield increased with an increase in N rates in the range of 112 to 224 kg ha ‐1 yr ‐1”
t0“Citrus”
Claim · model-written summary
Further N rate increases yielded diminishing fruit yield response, especially with DGF.
- Treatment
- further increase in N ratee0
- Outcome
- fruit yielde0
- Direction
- diminishinge0
- Qualifier
- quite marked for the DGFe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For further increase in N rate, the fruit yield showed a diminishing response, which was quite marked for the DGF”
t0“Citrus”
Claim · model-written summary
CRF required 1.79 kg N per Mg of fruit.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The N requirements for 1 Mg of fruit, mean across all N rates, were 1.79, 2.58, and 2.75 kg N for the CRF, FRT, and DGF sources, respectively”
t0“Citrus”
Claim · model-written summary
FRT required 2.58 kg N per Mg of fruit.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The N requirements for 1 Mg of fruit, mean across all N rates, were 1.79, 2.58, and 2.75 kg N for the CRF, FRT, and DGF sources, respectively”
t0“Citrus”
Claim · model-written summary
DGF required 2.75 kg N per Mg of fruit.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The N requirements for 1 Mg of fruit, mean across all N rates, were 1.79, 2.58, and 2.75 kg N for the CRF, FRT, and DGF sources, respectively”
t0“Citrus”
Claim · model-written summary
Leaf N stayed in the optimal 25–27 g kg ‐1 range at rates of at least 168 kg ha ‐1 yr ‐1 regardless of source.
- Treatment
- N rates ≥168 kg ha ‐1 yr ‐1e0
- Outcome
- Leaf N concentrationse0
- Direction
- maintainede0
- Value
- 25–27 g kg ‐1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf N concentrations were maintained within the optimal range (25–27 g kg ‐1 ) at N rates ≥168 kg ha ‐1 yr ‐1 , regardless of source of N”
t0“Citrus”
Claim · model-written summary
N rates and sources did not significantly affect fruit size or juice quality.
- Treatment
- Various N rates and sourcese0
- Outcome
- fruit size, nor juice quality parameterse0
- Direction
- did not significantly affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Various N rates and sources did not significantly affect the fruit size, nor juice quality parameters”
t0“Citrus”
Claim · model-written summary
Improved irrigation and fertilizer management minimized nitrate leaching beneath roots.
- Treatment
- improved management of irrigation and fertilizer placement and timing of applicatione0
- Outcome
- leaching of NO 3 ‐N below the root zonee0
- Direction
- minimizede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The improved management of irrigation and fertilizer placement and timing of application contributed to minimized leaching of NO 3 ‐N below the root zone”
t0“Citrus”
The same questions in other papers
nitrogen · yield · CitrusResults differ
16 papers in the same direction as this paper · 4 in the opposite direction
- positive
- no effect
- no effect
17 papers more in this group
See all 21 papers →nitrogen · quality: general · CitrusResults agree
1 paper in the same direction as this paper
- no effect
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.