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Applied experiences focused on citrus nutrition and water management for
mitigating HLBExperiencias aplicadas en la nutriciÓn
de cÍtricos y manejo de agua para mitigar del HLB
Davie Kadyampakeni
University of Florida
Citrus Research and Education Center
Lake Alfred, FL33850.
2o CIL, Quadalajara, Jalisco, Mexico 11 October, 2019
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Outline
Status of HLB in FL: What we know now
Irrigation studies for managing HLB: Examples
Nutrition studies for managing HLB: Highlights
Summary
Acknowledgements
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Current Status of HLB
• Citrus accounts for $10 billion in economic activity
• Pre-HLB 240 million boxes (10 billion tons)
• Current 80 million boxes (3.3 billion tons), about 67% reduction in
production
• Production costs up to $2100 per acre due to HLB
• Significant reduction in production area
• Declined tree performance, root loss and significant defoliation
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Irrigation strategies for managing HLB• Preventative measures: HLB negative (healthy trees)
• Frequent irrigation (daily or multiple times a day) e.g. Citrus Under Cover Production System• Regulated deficit irrigation • Partial root zone dryingPlus Asian psyllid control
• Curative management of HLB positive trees (asymptomatic trees)• Daily irrigation plus Asian psyllid control• Managing pH to optimum levels for nutrient availability• Improved nutrition programs via fertigation
• Remediation/Management of HLB affected trees (symptomatic trees)• Daily irrigation plus Asian psyllid control• Managing pH to optimum levels for nutrient availability• Fertigation practices
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Irrigation strategies for managing HLB
Field studies on irrigation conducted in:
• Irrigation studies at 3 sites: Ave Maria, Avon Park, Arcadia (2013-2014)
Comparison of Daily, IFAS (recommended by UF) and Intermediate Irrigation Schedules based on Florida Automated Weather Network (FAWN) evapotranspiration
• Advanced Citrus Production Systems (ACPS) studies:
Two Sites: Immokalee at UF/IFAS, SWFREC, and Lake Alfred (2008 to 2011)Comparison of drip and modified microsprinkler irrigation with grower
practices
• Greenhouse studies conducted at Immokalee, SWFREC (2014-2015)
Comparison of HLB vs non-HLB affected citrus
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Irrigation studies
Water use of HLB affected trees in south west and central Florida
• Daily > Intermediate > IFAS irrigation scheduling
• Daily irrigation could help in managing HLB affected trees, reduce tree water stress
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Irrigation studiesTotal available water (%) in southwest and central Florida
• Increasing TAW with depth, greater uptake in the top 6 inches.
• Greater TAW in in top 15 cm than lower 15-45 cm for Daily than Intermediate and IFAS irrigation schedule.
Irrigation treatment
Soil depth (cm)
Commercial site
Arcadia Avon Park Immokalee
Daily
0-15 68.9dc 80.7b 68.1bc
15-30 72.2c 58.7c 75.3b
30-45 98.2a 87.8a 97.9a
Intermediate
0-15 52.2fg 56.3cd 64.5c
15-30 58.9ef 61.4c 46.6d
30-45 98.8a 74.3b 42.3d
IFAS
0-15 48.1g 49.7d 46.6d
15-30 80.9b 50.4d 32.1e
30-45 62.3de 61.9c 69.3bc
ANOVA
Arcadia Avon Park Immokalee
Source of variation Pr > F Pr > F Pr > F
Irrigation treatment <.0001 <.0001 <.0001
Soil depth <.0001 <.0001 <.0001
Irrigation treatment x Soil depth <.0001 <.0001 0.0876
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Irrigation studies in central and southwest Florida
Avon Park
Vol
umet
ric w
ater
con
tent
(m
3 m-3
)
0.00
0.02
0.04
0.06
0.08
0.10
0.12 IFAS
Intermediate
Daily
Immokalee
Soil depth (cm)
0-15 15-30 30-45
Vol
umet
ric w
ater
con
tent
(m
3 m-3
)
0.00
0.02
0.04
0.06
0.08
0.10
0.12 IFAS
Intermediate
Daily
ArcadiaV
olum
etric
wat
er c
onte
nt (
m3 m
-3)
0.00
0.02
0.04
0.06
0.08
0.10
0.12IFAS
Intermediate
Daily
Arcadia
0.10 0.15 0.20 0.25
Sap
flow
(g
m-2
h-1
)
18
20
22
24
26
28
30
Syx = 0.2794
P = 0.02
r2 = 0.999***
Y = 13.62 + 57.4x
Avon Park
0.04 0.06 0.08 0.10
Sap
flow
(g
m-2
h-1)
20
22
24
26
28
30
32
34
36
38
Syx = 0.5719
P = 0.0353
r2
= 0.999***
Y = 12.7 + 276.6x
Immokalee
Volumetric water content (m3 m
-3)
0.04 0.06 0.08 0.10 0.12 0.14
Sap
flow
(g
h-1 m
-2 h
-1)
5
10
15
20
25
30
35
40
45
Y = -27.5 + 534.3x
Syx = 1.523
P = 0.0488
r2= 0.994***
Moisture contents and significant relationships with sapflow
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Water use of HLB affected trees in southwest Florida under greenhouse conditions
• 22 to 35% greater water use for Non-HLB affected trees
• Inter-season and annual variability in water use
• Comparable water use between varieties
Month -year ETo
(mm d-1)
ETc (mm d-1) ETc diff. (%)‡
Hamlin-Non HLB Hamlin-HLB
Jan-Jun-14 3.57 2.97 2.23 23.73
Jul-Dec-14 4.42 4.16 2.63 34.82
Jan-Jun-2015 3.38 4.08 2.83 29.82
Jun-Oct-15 3.73 4.94 3.18 35.20
Overall Average 3.79 4.00a** 2.69b** 30.75
Valencia-Non HLB Valencia-HLB
Jan-Jun-14 3.57 2.83 2.22 22.28
Jul-Dec-14 4.42 3.97 2.83 28.85
Jan-Jun-2015 3.38 3.85 2.69 30.98
Jun-Oct-15 3.73 4.79 3.56 26.42
Overall Average 3.79 3.82a** 2.80b** 26.99**
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Citrus Crop Coefficients between HLB and Non-HLB affected Citrus Trees
• Patterns of Kc similar for HLB affected and non-affected trees
• Non-affected tree Kc similar to those found to field trees prior to greening
• Infected trees consistently with lower Kc
• 35.2% in 2014 and 20.8% in 2015
0
0.2
0.4
0.6
0.8
1
1.2
Dec-13 Feb-14 Apr-14 Jun-14 Aug-14 Oct-14 Dec-14
Cro
p C
oe
ffic
ien
t (K
c)
Date
Hamlin Hamlin - HLB Valencia Valencia - HLB IFAS
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Dec-14 Feb-15 Apr-15 May-15 Jul-15 Sep-15 Oct-15 Dec-15C
rop
Co
eff
icie
nt
(Kc)
Date
Hamlin Hamlin - HLB Valencia Valencia - HLB IFAS
Crop coefficient (Kc) for HLB affected trees in southwest Florida under greenhouse conditions
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Nutrition studies for managing HLB: Highlights• Advanced Citrus Production Systems (ACPS) studies:
Two Sites: Immokalee at UF/IFAS, Immokalee, and Lake Alfred (2008 to 2011)
Comparison of drip and modified microsprinkler fertigationsystems with Conventional grower practices
Two ACPS systems: drip (DOHS) and microsprinkler (RM, MOHS), and conventional microsprinkler practice (CMP)
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Leaf NPK concentration
ACPS Nutrition Studies
Fertigation practice
CMP DOHS MOHS
Lea
f co
nc.
(%)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
N
P
K
Leaf NPK conc. were in
optimum or high range.
CMP needs more fertilizer and
water per ha at 1 to 2.5 years than
ACPS (Schumann et al. 2010)
Nutrient efficiency (m3/kg N)
Fertilization method
CMP MOHS DOHS-S DOHS-C35
Eff
icie
ncy
(cu
bic
m/k
g N
)
0
10
20
30
40
50
60
After 1 year
After 2.5 years
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N and P accumulation on Immokalee sandFertigation
methodCMP Drip RM CMP Drip RM
Tissue N (kg ha-1) P (kg ha-1)
Leaves 24.00 49.78 37.10 1.34 1.69 1.48
Fruits 22.40 15.78 29.98 2.68 1.03 2.28
Branches/trunk 20.70 28.38 26.44 4.76 3.80 4.22
Roots 11.60 20.82 20.20 2.85 2.98 2.96
Total 78.70 114.78 113.72 11.64 9.52 10.95
ACPS Nutrition Studies (2)
High N accumulation with ACPS than CMP but P
accumulation similar for all practices.
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ACPS Nutrition Studies (3)
Leaf NPK concentration (%) determined in
June 2009 at Immokalee.
• Sufficient NPK concentrations.
• Drip OHS was effective in
enhancing N uptake compared with
the other two irrigation methods
studied.
• Leaf P concentration was high
(0.17-0.30%) in all treatments
• Leaf K concentration was within
optimum and high ranges (1.2-
2.4%) suggesting no significant
differences between ACPS and
Conventional method.
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ACPS Nutrition Studies (4)
0
0.5
1
1.5
2
2.5
3
Irrigated Non-irrigated Irrigated Non-irrigated
Ammonium N Nitrate N
Con
cen
trati
on
(m
g/k
g)
Conventional practice Drip OHS Microsprinkler OHS
Ammonium and nitrate distribution in the irrigated and non-irrigated zone
• Greater inorganic
N in irrigated than
non-irrigated
zones
• Better N contents
in irrigated zones
of ACPS than
Conventional.
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ACPS Nutrition Studies (5)
0
10
20
30
40
50
60
70
80
90
Co
nce
ntr
atio
n (
mg/
kg)
Mehlich 1 P Irrigated
Mehlich 1 P Non-irrigated
Soil P distribution in the irrigated and non-irrigated zones
• Greater P in
irrigated than non-
irrigated zones
• Soil P contents in
irrigated zones of
Drip greater than
Conventional.
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ACPS Nutrition Studies (6)
Lateral ammonium-N (mg/kg) distribution in July 2010 at the Lake Alfred site using drip fertigation.
Cross-row (cm)
0 5 10 15 20 25 30
With
in ro
w (c
m)
0
5
10
15
20
25
30
0.4
0.5
0.6
0.7
0.8
0.9
D
T
Higher NPK conc.
in irrigated vs.
non-irrigated zones
of drip fertigation.
D=area below
dripper, T=tree
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ACPS Nutrition Studies (7)
Mehlich 1 P (mg kg-1)
20 40 60 80 100 120 140 160
Depth
(cm
)
0
20
40
60
80
100
120
140
DOHS-Swingle
CMP
DOHS-C35
MOHS
Mehlich 1 P (mg kg-1)
0 10 20 30 40 50
Depth
(cm
)
0
20
40
60
80
100
120
140
CMP
DOHS
MOHS
Immokalee
Candler
Vertical P distribution at Immokalee and Lake
Alfred sites in 2010
Less P leaching with OHS than CMP in 2010.
High P at Lake Alfred than Immokalee
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ACPS Nutrition Studies (8)
Canopy volume as a function of fertilization practice at the Lake Alfred site
ACPS fertigation
had greater tree size
than conventional
practice
Date
11/1/09 1/1/10 3/1/10 5/1/10 7/1/10
Can
opy
volu
me
(m3 )
0.0
0.5
1.0
1.5
2.0
2.5
DOHS-Swingle
CMP
MOHS
DOHS-C35
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ACPS Nutrition Studies (9)
Lateral RLD (cm cm-3) distribution using CMP
Lateral RLD (cm cm-3) distribution using DOHS
Cross-row (cm)
0 10 20 30 40
With
in r
ow
(cm
)
0
5
10
15
20
25
30
0.07
0.08
0.09
0.10
0.11
MT
Cross-row (cm)
0 10 20 30 40
With
in r
ow
(cm
)
0
5
10
15
20
25
30
0.15
0.20
0.25
0.30 T
D
D
T=tree, M=microsprinkler
Roots uniformly distributed
around the tree
T=tree, D=dripper, Roots
concentrated below the
drippers
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Positions in the irrigated zones of showed higher root density than non-irrigated zones
M=microsprinkler
T=tree
Cross-row (cm)
0 10 20 30 40
With
in r
ow
(cm
)
0
5
10
15
20
25
30
0.08
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
MT
ACPS Nutrition Studies (7)
Lateral root density (cm cm-3) distribution
using ACPS microsprinkler
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Summary
Daily, frequent irrigation critical for improved tree performance, soil moisture distribution and water use.
HLB affected trees use 22 to 35% less water than the non-affected trees.
ACPS practices could be adapted to grower practices for vigorous tree growth, water use, greater root density and nutrient accumulation.
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Acknowledgements
• Dr. Morgan, Dr. Schumann, Dr. Ebel, Dr. Hamido – University of Florida
• Grove/Orchard Space: • UF/IFAS SWFREC, Immokalee, FL
• Gapway Groves, Auburndale, FL
• Pacific Inc., Ave Maria, FL
• Orange Co, Arcadia, FL
• Ben Hill Griffin, Avon Park, FL
• Funding: Southwest FL WMD, FDACS, UF/IFAS
• Thanks to Mrs. Ana Villalpando and Dr. Medina for the invitation. Muchas Gracias!