Evaluation of NCDA&CS Boron Sufficiency Ranges
for Flue-Cured Tobacco
C.H. Jernigan, D.H. Hardy, K. A. Hicks, and M.S. McGinnis NC Dept. of Agriculture & Consumer Services
M.C. Vann and L.R. FisherNC State University
48th Tobacco Worker’s ConferenceJanuary 16, 2018
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Today’s Presentation• Review of boron (B)
• History of growth concerns leading to research objectives
• Materials and Methods
• Results
• Findings and practical applications
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Introduction to Boron• B is an essential micronutrient
• Uptake primarily as H3BO30
• Xylem transported to leaves
• Transport through phloem varies with species
• Primary function is in cell wall structural integrity
• Essential for transport of H2O, nutrients, and sugars to developing tissues
Havlin, J. L., S. M. Tisdale, W. L. Nelson, and J. D. Beaton. 2014. Soil fertility and fertilizers. An introduction to nutrient management. Eighth edition. Pearson.
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Introduction to Boron• Crops vary in need
– High needs: peanuts, cotton, alfalfa, sweet potato, apples– Flue-cured tobacco is not known to have high need
• 0.09 lb B in 2500 lb per acre crop (Miner and Tucker, 1990)
– Toxicity can be an issue if over-applied
• Deficiency symptoms vary widely by crop– In tobacco, distortion of young leaves & terminal bud death
(Miner and Tucker, 1990) – Visual symptoms not well documented in tobacco until recently
Miner, G. S. and M. R. Tucker. 1990. Plant analysis as an aid in fertilizing tobacco. IN: Westerman, R. L., editor. Soil testing and plant analysis. 3rd. Ed. Madison (WI): Soil Science Soc. of America, Inc. p. 645-57. (SSSA book series:3).
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
https://diagnosis.ces.ncsu.edu/tobacco/ (Forensic floriculture; Brian Whipker, Matthew Vann)
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Introduction to Boron• In soil, H3BO3
0 predominates in solution pH range 5 – 9 – Transported through soil to roots via mass flow & diffusion
• Absorption to clay, OM, and Fe/Al compounds
• Plant availability– pH dependent, especially at pH > 6.5– Very soluble and subject to leaching in sandy, low OM soils
• Soil testing for B– Hot water extraction, Mehlich 3, DTPA– NCDA does not analyze B; recommend 0.5 to 2 lb per acre for
crops with high need
Havlin, J. L., S. M. Tisdale, W. L. Nelson, and J. D. Beaton. 2014. Soil fertility and fertilizers. An introduction to nutrient management. Eighth edition. Pearson.
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
2014 Growth Concerns• Numerous growth abnormalities in NC flue-cured
tobacco in eastern NC
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
2014 Growth Concerns• Potential causes…..
– Boron deficiency– Calcium deficiency– Off-type (genetically impure) plants– Budworm injury– Chemical injury
• Some cases, nutritionally…..– Low and deficient B found– Low and deficient Ca found
Ca deficiency
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
2014 Growth Concerns• Other cases, tissue analysis did not confirm any concerns
– Tobacco may grow out problem while old symptoms are present– Questioning of sufficiency ranges– Questioning of which plant part to sample
• Foliar B applied in some fields– After application, tobacco grew normally…response to B?
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
NCDA Plant Tissue Guidelines• Interpretation of ppm in bud and MRML; based on bud
– Deficient < 10.9– Low 11.0 – 17.9– Sufficient 18.0 – 75.0– High 75.1 – 150.0– Excessive > 150
Same interpretation as published by Campbell, C. R. 2000. Tobacco, Flue-Cured. Sufficiency Ranges for Plant Analysis in Southern Region of US.
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
2014 Growth Concerns• Why might this be B?
– Bud death indicated B might be involved
– Symptoms in early rapid growth phase, tissue development
– Concern concentrated on sandy, low OM soils
– Wet winters and growing seasons, much leaching occurred
– Some cases pH > 6.2
– Less use of premium tobacco grades with micronutrients• 0.02% to 0.5% B (currently available)• Supply 0.2 to 3.0 lb B per acre
– NCDA&CS soil test does not include B….
In winter of 2015, decision to study B nutrition in flue-cured tobacco
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Objectives• Evaluate current boron sufficiency ranges• Determine if correct plant part is being used• Evaluate growth stage effects on B concentration
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Materials and Methods• 5 locations at research stations to provide a range of soil type
20151- Border Belt Tobacco Res. Stn5 - Lower Coastal Plain Res. Stn8 - Oxford Tobacco Res. Stn11- Sandhills Res. Stn. 13 - Upper Coastal Plain Res. Stn
2016 & 20175 - Lower Coastal Plain Res. Stn8 - Oxford Tobacco Res. Stn11- Sandhills Res. Stn. 13 - Upper Coastal Plain Res. Stn5 - Hugo Research Station
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Materials and Methods• Transplant production practices
– B added to float bed to achieve 1 ppm nutrient solution– B levels in transplants were sufficient
• ~ 0.002 lb/ac B taken to the field in transplants
• Standard field production practices otherwise
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Materials and Methods• Treatments & Experimental Design
– Soil applied B• 0, 0.5 1.0, 2.0, 5, and 10 lb per acre• Band-applied as a stream & covered with a rolling cultivator
– Foliar applied B• AN-F - as needed if B deficiency visually seen (only in 2015)• 0.5 FS - 0.25 lb per acre applied at 2nd cultivation and layby• 0.5 F - 0.5 lb per acre applied at layby • 1.0 F - 1.0 lb per acre applied at layby (only in 2016 & 2017)
– RCBD, 4 replications- 4-row, 50-ft plots
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Materials and Methods• Data collection
– Initial soil fertility and soil B levels by Mehlich 3– Plant measurements biweekly until flowering– Plant analysis - green tissue and cured leaf
• N, P, K, Ca, Mg, S, Fe, Mn, Cu, B, Zn, Na• Green leaf sampling
– Bud and most recent mature leaf (MRML)– Three events
» Day of / prior to 1st FS application (~ 3 wk AT)» Day of / prior to 2nd FS application (~ 7 wk AT)» At topping (MRML only)
– Yield, grade index, value
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Materials and Methods• Statistical analysis
– ANOVA by SAS• Locations analyzed separately • Plant part treated as split-plot treatment design• Mean separation by LSD0.05 for significant effects
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Results and Discussion• Strong main treatment effect of B rate on B plant tissue
levels in bud and MRML at all locations
• B levels were significantly different in plant parts at the first two sampling events (treatment x plant part interaction)
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
0
5
10
15
20
25
30
35
40
0 0.5 1 2 5 10 0.5FS 0.5 F 1.0 F
B pp
m
B Rate lb / acre
Bud
Event 1 Event 2
cde
bcd bcb
a a
cde e de
DCDBC
AA
BBBCD
2017 Boron Plant Levels- SRS
18 ppm
Means with same letters not sig. different at 0.05 level by LSD.
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
0
20
40
60
80
100
120
140
0 0.5 1 2 5 10 0.5FS 0.5 F 1.0 F
B pp
m
B Rate lb / acre
MRML
Event 1 Event 2
bcb
aa
AA
B
BC
D
2017 Boron Plant Levels- SRS
CDD D
cdd d d d 18 ppm
Means with same letters not sig. different at 0.05 level by LSD.
75 ppm
D
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
0
10
20
30
40
50
60
70
80
90
100
0 0.5 1 2 5 10 0.5FS 0.5 F 1.0 F
B pp
m
B Rate lb / acre
MRML- Event 3
aa
cd
d
2017 Boron Plant Levels - SRS
bc bcc
b
cd
18 ppm
Means with same letters not sig. different at 0.05 level by LSD.
75 ppm
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 0.5 1 2 5 10 0.5FS 0.5 F 1.0 F
lb /
acre
B Rate lb / acreHugo LCPRS SRS OTRS UCPRS
a
2017 Cured Leaf Yield
Means with same letters not sig. different at 0.05 level by LSD.
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
0
10
20
30
40
50
60
70
80
90
100
0 0.5 1 2 5 10 0.5FS 0.5 F 1.0 F
Gra
de in
dex
B Rate lb / acreHugo LCPRS SRS OTRS UCPRS
2017 Grade Index
Means with same letters not sig. different at 0.05 level by LSD.
a
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
0
1000
2000
3000
4000
5000
6000
7000
0 0.5 1 2 5 10 0.5FS 0.5 F 1.0 F
$ / a
cre
B Rate lb / acreHugo LCPRS SRS OTRS UCPRS
2017 Cured Leaf Value
Means with same letters not sig. different at 0.05 level by LSD.
a
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Boron Toxicity from Soil Applications
SRS 6/25/201510.0 lb per acre
~ 275 ppm MRML
LCPRS 7/02/20152.0 lb per acre
~ 62 ppm MRML
UCPRS 7/15/20151.0 lb per acre
~ 90 ppm MRML
Upper end of sufficiency is 75 ppm, Excessive > 150 ppm
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Boron Toxicity from Foliar Applications
LCPRS 20160.5 lb per acre foliar
~ 40 ppm MRML
LCPRS 20161.0 lb per acre foliar
~ 47 ppm MRML
Upper end of sufficiency is 75 ppm, Excessive > 150 ppm
UCPRS 20170.25 lb per acre foliar
~ 26 ppm MRML~48 ppm Harvest Leaf
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
0100200300400500600700800
0 0.5 1 2 5 10 0.5FS 0.5 F 1.0 F
B pp
m
B Rate lb / acre
Harvest Leaf - Event 3a
b
c
d
Boron Toxicity - LCPRS
cd cd cdd
Means with same letters not sig. different at 0.05 level by LSD.
75 ppm
150 ppm
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Findings• At low rates of B, bud & MRML data indicate borderline
low B with no deficiency symptoms expressed
– 2015, yield & quality not affected when B was not applied (2 sites); toxicity negatively affected yields at high rates
– 2016, yield response at only one of 5 sites• SRS- unexpected and unexplained
– 2017, yield & quality not affected when B was not applied at 5 sites; yield & quality not affected by toxicity at high rate
• Present sufficiency ranges could potentially be lowered
• Either bud or MRML may be sampled
• Sampling 3 to 4 weeks after transplant may be too soon
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Findings• In the MRML, later sampling resulted in higher
concentrations, especially at the higher rates • Toxicity symptoms in MRML were visually & analytically
identified– Over application has potential to reduce yield & quality
• Micronutrient deficiencies are unpredictable– Soil & environmental conditions affect availability, uptake,
growth rate, etc.– Some years deficiencies may be prevalent & then nonexistent
for a number of years– Certain geographical areas may be more prone than others to
have deficiencies
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Practical Applications• If boron remains a concern:
– A rate < 1 lb/ac B soil applied in a band appears to be safe• Attention to placement….not too close to plant
– Foliar applications of 0.5 lb/ac B generally appear safe • Split applications of 0.25 lb/ac B• Single application of 0.5 lb/ac B
UCPRS 7/15/20151.0 lb per acre
~ 90 ppm MRML
SRS 6/29/20170.5 lb per acre foliar
~ 37 ppm MRML~ 74 ppm HL
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
Acknowledgements• Lloyd Ransom – BBTRS, Jeremy Martin – SRS, Brett Bynum
- LCPRS, Louis Pitt – UCPRS, Carl Watson – OTRS• NCSU tobacco program and NCCES agents• Regional agronomists for field work and oversight• NCDA Plant Lab for analyzing samples
2018
_TW
C09
_Jer
niga
n.pd
fT
WC
2018
(48)
- D
ocum
ent n
ot p
eer-
revi
ewed
