Abstract
Fifty-year-old 'Booth 7' and 'Lula' avocado (Persea Americana Mill.) trees were used to investigate the effect of foliarly applied urea and boron (B) on leaf and inflorescence nitrogen (N) and B contents, and crop yields. The urea trial included soil application of 100 lb N per acre per year (non-urea sprayed control), 10 Ib per acre of urea-N applied foliarly plus 90 Ib soil-applied N per year, and 20 Ib per acre of urea-N applied foliarly plus 80 Ib soil applied-N per year. Applications of urea were made during fruit set and early development. These preliminary data show that urea-N treatments increased leaf N 8-57% but there were no differences in N concentration in leaves among treatments sampled 28 days after application. Foliar application of urea increased fruit yield of 'Booth7' but decreased fruit yield of 'Lula. Boron treatments consisted of two rates of B (1 or 2 Ib B/acre) and a non-sprayed control. Boron at the 1 Ib B/acre and 2 Ib B/acre rates increased leaf and inflorescence B concentration of B of 'Lula and 'Booth 7' 4 weeks after application. There was a trend for trees treated with B to have greater crop yields than non-sprayed controls. Preliminary results suggest foliarly applied urea and B affect leaf and inflorescence content of these nutrients and may influence crop yields. Foliarly-applied urea has been used as a supplement to soil-applied nitrogen fertilizer to improve tissue N content, fruit set and yields in a number of crops; however, research on foliar application of urea for avocado has lead to conflicting results. Abou Aziz et al., (1975) reported foliarly-applied urea increased avocado fruit set, fruit yield, size, and weight. Foliar-applied 15 N-enriched urea on avocado showed substantial uptake of N and urea-N was translocated from leaves to developing fruit (Zilkah et al., 1987). However, Nevin et al., (1990) reported uptake of 14 C enriched urea by avocado leaves was physiologically insignificant (<7% of the total urea applied). Regardless of these findings, some avocado growers in south Florida are applying N fertilizer foliarly. This project was designed to better understand effects of foliar-applied urea on avocado trees under Florida production conditions.
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Claims 5
Claim · model-written summary
Urea-N treatments increased leaf N by 8-57% in avocado trees compared with the non-urea sprayed control.
- Taxon
- avocado
Persea americanae0 - Organ / stage
- leafe1
- Treatment
- urea-Ne1
- Outcome
- leaf Ne1
- Direction
- increasede1
- Value
- 8-57%e1
- Comparator
- non-urea sprayed controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“AVOCADO TREES”
e0“Fifty-year-old 'Booth 7' and 'Lula' avocado (Persea Americana Mill.) trees”
e1“urea-N treatments increased leaf N 8-57% but there were no differences in N concentration in leaves among treatments sampled 28 days after application”
e2“non-urea sprayed control”
Claim · model-written summary
Urea-N treatments produced no differences in leaf N concentration among treatments sampled 28 days after application.
- Taxon
- avocadoPersea americanae0
- Treatment
- urea-Ne1
- Outcome
- N concentration in leavese1
- Direction
- no differencese1
- Comparator
- treatmentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“AVOCADO TREES”
e0“Fifty-year-old 'Booth 7' and 'Lula' avocado (Persea Americana Mill.) trees”
e1“urea-N treatments increased leaf N 8-57% but there were no differences in N concentration in leaves among treatments sampled 28 days after application”
Claim · model-written summary
Foliar urea increased fruit yield of the 'Booth7' avocado cultivar.
- Taxon
- avocadoPersea americanae0
- Material
- Booth7e3
- Treatment
- Foliar application of ureae3
- Outcome
- fruit yielde3
- Direction
- increasede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“AVOCADO TREES”
e0“Fifty-year-old 'Booth 7' and 'Lula' avocado (Persea Americana Mill.) trees”
e3“Foliar application of urea increased fruit yield of 'Booth7'”
Claim · model-written summary
Boron applied at 1 and 2 lb per acre increased leaf and inflorescence B concentration compared with a non-sprayed control.
- Taxon
- avocadoPersea americanae0
- Organ / stage
- leaf and inflorescencee5
- Treatment
- Borone5
- Outcome
- leaf and inflorescence B concentratione5
- Direction
- increasede5
- Comparator
- a non-sprayed controle6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“AVOCADO TREES”
e0“Fifty-year-old 'Booth 7' and 'Lula' avocado (Persea Americana Mill.) trees”
e5“Boron at the 1 Ib B/acre and 2 Ib B/acre rates increased leaf and inflorescence B concentration”
e6“a non-sprayed control”
Claim · model-written summary
Boron-treated avocado trees tended to have greater crop yields than non-sprayed controls, but the difference was a trend only.
- Taxon
- avocadoPersea americanae0
- Treatment
- Be7
- Outcome
- crop yieldse7
- Direction
- greatere7
- Comparator
- non-sprayed controlse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“AVOCADO TREES”
e0“Fifty-year-old 'Booth 7' and 'Lula' avocado (Persea Americana Mill.) trees”
e7“There was a trend for trees treated with B to have greater crop yields than non-sprayed controls”
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See all 5 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.