![At harvest in 2006 (k), 2007 (%), and 2008 (j), sugar beet root yield and quality response to (calcium) ammonium nitrate fertilizer broadcast incorporated preplant or preplant and in-season before row closure at 56'56 and 84'84, respectively. Bars represent SE of means. NS, ' , *, **, *** Nonsignificant or significant at P50.1, 0.05, 0.01, or 0.001, respectively (n ]12).](https://www.researchgate.net/profile/John-Zandstra-2/publication/276032428/figure/fig1/AS:391765296205825@1470415533201/At-harvest-in-2006-k-2007-and-2008-j-sugar-beet-root-yield-and-quality_Q320.jpg)
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Sugar beet (
Beta vulgaris
L.) storage quality in large
outdoor piles is impacted by pile management but not by
nitrogen fertilizer or cultivar
Laura L. Van Eerd
1,2
, Katelyn A. Congreves
1,2
, and John W. Zandstra
2
1
School of Environmental Sciences; and
2
University of Guelph Ridgetown Campus, Ridgetown, Ontario, Canada
N0P 2C0 (e-mail: lvaneerd@ridgetownc.uoguelph.ca)
.
Received 23 March 2011, accepted 5 August 2011.
Van Eerd, L. L., Congreves, K. A. and Zandstra, J. W. 2012. Sugar beet (Beta vulgaris L.) storage quality in large outdoor
piles is impacted by pile management but not by nitrogen fertilizer or cultivar. Can. J. Plant Sci. 92: 129139. Even though
storage results in lower sucrose recovery from sugar beets, physical constraints dictate that a significant proportion of the
sugar beet crop can be stored up to 120 d before processing. From 2006 to 2010, N fertilization (0220 kg N ha
1
), sugar
beet cultivar, and pile management method were independently evaluated to determine their effects on sugar beet
storability in large outdoor piles. At harvest, five representative sugar beet samples from the N and cultivar field trials were
placed in a large outdoor storage pile. Sugar beet quality assessments were taken at harvest and three times over the
storage season. On the last retrieval date only, sugar beet samples were retrieved from piles managed via the length- vs.
end-removal method. Although there were differences among N treatments and cultivars in sugar beet quality at harvest,
there were no storage date by N treatment or storage date by cultivar interactions for any parameters measured indicating
that N fertilization or cultivar did not influence the ability to maintain sugar beet quality in large outdoor piles. The length-
removal method of pile management had better quality sugar beets compared with the standard end-removal method.
Hence, sugar beet producers do not need to modify production practices to optimize storability, but sugar beet processors
can improve sucrose recovery by removing sugar beets lengthwise along both sides of large piles as opposed to the standard
end-removal method.
Key words: Sucrose, pile removal, ammonium nitrogen fertilizer, variety, EuroMaus
Van Eerd, L. L., Congreves, K. A. et Zandstra, J. W. 2012. La qualite´ de la betterave sucrie` re (Beta vulgaris L.) durant le
stockage exte´ rieur en tas importants est affecte´ e par la me´ thode de gestion des stocks, mais pas par l’usage d’engrais azote´ sni
le cultivar. Can. J. Plant Sci. 92: 129139. Bien que le stockage re
´duise la quantite
´de sucrose extraite de la betterave
sucrie
`re, les contraintes physiques ne
´cessite l’entreposage d’une part importante de la re
´colte avant transformation pendant
un maximum de 120 jours. De 2006 a
`2010, les auteurs ont e
´value
´se
´pare
´ment la fertilisation avec des engrais azote
´s
(0 a
`220 kg de N par hectare), le cultivar et la me
´thode de gestion des stocks en vue d’e
´tablir l’incidence de ces parame
`tres
sur la capacite
´d’entreposage des betteraves sucrie
`res en gros tas exte
´rieurs. A
`la re
´colte, ils ont pre
´leve
´cinq e
´chantillons
repre
´sentatifs de betteraves dans les parcelles soumises aux essais de fertilisation N et de cultivar, et les ont de
´pose
´s dans
des amas importants stocke
´sa
`l’exte
´rieur. Ils ont ensuite e
´value
´la qualite
´des betteraves a
`la re
´colte et a
`trois autres
moments, durant l’entreposage. A
`la dernie
`re date seulement, ils ont re
´cupe
´re
´les e
´chantillons des tas ge
´re
´s selon la dure
´e
d’entreposage ou par re
´cupe
´ration a
`une extre
´mite
´de l’amas. Bien que l’usage d’engrais N et le cultivar entraı
ˆnent des
variations au niveau de la qualite
´a
`la re
´colte, il n’existe aucune interaction entre la fertilisation N ou la date de stockage
et le cultivar, quel que soit le parame
`tre mesure
´, signe que les engrais N et le cultivar n’exercent aucune influence sur la
capacite
´de la betterave a
`conserver sa qualite
´quand elle est stocke
´e en tas importants, a
`l’exte
´rieur. La gestion des stocks
par re
´cupe
´ration en fonction de la dure
´e d’entreposage donne des betteraves de meilleure qualite
´que la me
´thode usuelle,
qui consiste a
`pre
´lever l’extre
´mite
´de la pile. Par conse
´quent, les producteurs de betterave sucrie
`re n’ont pas besoin de
modifier leurs pratiques culturales pour optimiser les capacite
´s de stockage de leur produit. En revanche, les transfor-
mateurs pourraient accroı
ˆtre la quantite
´de sucrose extraite en pre
´levant les betteraves selon leur dure
´e d’entreposage, des
deux co
ˆte
´s de la pile, au lieu de ne les pre
´lever qu’a
`une extre
´mite
´.
Mots cle
´s: Sucrose, extraction des stocks, engrais azote
´ammonium, varie
´te
´, EuroMaus
In 2007, Canadian sugar beet production had a farm-
gate value of $9.1 million and $39 million for about 95
and 600 growers on approximately 4000 and 13 800 ha
in Ontario (Ontario Sugarbeet Growers Association,
2008, unpublished data) and Alberta (Chaudhary 2009),
respectively. Sugar beets grown in North America are
produced under grower-owned cooperatives that pro-
cess sugar beets into sucrose. As opposed to paying
growers based on tonnage only, as of 2007, Michigan
Sugar Company Inc. (MSC) paid growers based on
sucrose content and sugar beet tonnage. Thus, methods
that maximize sucrose production and minimize sucrose
losses would be beneficial for all producers, who share
Abbreviations: CJP, clear juice purity; MSC, Michigan Sugar
Company Inc.; RWS, recoverable white sugar
Can. J. Plant Sci. (2012) 92: 129139 doi: 10.4141/CJPS2011-054 129
Can. J. Plant Sci. Downloaded from pubs.aic.ca by 54.152.109.166 on 09/13/15
For personal use only.
cooperative profits. Considering the potential for sig-
nificant sucrose losses during storage, research should
focus on minimizing losses during this period.
The physical constraints of sugar beet processing
operations dictate that much of the crop be stored for
a portion of the winter (up to 120 d), even though the
practice results in a decline in sucrose recovery. During
storage, sugar beets undergo chemical alterations and
the amount of recoverable white sucrose tends to decline
over time. Other than sucrose loss due to root respira-
tion, sugar beet sucrose losses during storage can be
attributed to sugar beet physical injury (Cole 1977;
Wyse and Peterson 1979), raffinose synthesis, sugar
inversion, and fluctuations in storage temperature (Cole
and Bugbee 1976). Sucrose losses during storage can be
substantial, and are estimated at 250500 g sucrose
Mg
1
d
1
(Bugbee 1993). Not only do storage condi-
tions influence sugar beet storability, but Martin
et al. (2001a) observed that pre-harvest and harvest
factors may affect sugar beet quality, which, in turn,
may affect storage and processing quality.
Observations at sugar beet storage piles have also
raised the question of whether or not different sugar
beet production practices have an effect on sugar beet
storability. The winters of 20042005 and 20052006
were unusually warm in southwestern Ontario, which
likely contributed to significant rotting in sugar beet
storage piles. During the 20042005 storage period, an
estimated 40 000 Mg of sugar beets were discarded in
Ontario, which is equivalent to a loss of 24% of the
stored Ontario crop and similar losses were observed at
each of MSC’s 14 other piling stations (Wayne Martin,
MSC, personal communication). While warm condi-
tions resulted in challenging storage conditions, other
factors also seemed to be involved. As the rotting sugar
beets were removed from storage, MSC personnel noted
that side-by-side layers in the pile, suggesting sugar beets
from different loads/producers, varied in quality with
some layers being of acceptable quality for processing
while others were rotted (Wayne Martin, MSC, personal
communication). Hence, the observations indicated that
different production practices may have had an influ-
ence on sugar beet storability, especially under poor
storage conditions. However, it is not known which
production practices affected sucrose loss and rotting
during storage. Although weather and sugar beet hand-
ling at harvest are known to impact storage losses (Cole
1977; Scott and Jaggard 2000), there is little informa-
tion on the impact of grower practices such as fertility
and/or crop cultivar on storage losses.
One critical pre-harvest factor that influences sugar
beet quality is N fertility, which is negatively correlated
to sucrose concentration and quality (Eslami et al. 1988;
Bilbao et al. 2004). Thus, the application of an appro-
priate level of N fertilization is crucial to optimize
sucrose production. Although the impact of N fertilizer
rate on sugar beet yield, recoverable white sucrose and
purity at harvest is well understood (Eslami et al. 1988;
Bilbao et al. 2004), very little is known about the impact
of N fertility on sucrose losses or susceptibility to rotting
during long-term storage in large piles.
Sugar beet cultivar may be another pre-harvest factor
that affects sugar beet storability, particularly because
varieties differ significantly in sucrose content. Small
differences in N response among varieties have been
observed (Stevens et al. 2008), which may contribute to
differences among varieties in storage characteristics.
There are inconsistent results in the literature regarding
cultivar influence on storability, as some studies have
found evidence of varietal differences in storability
(Akeson and Widner 1981; Martin et al. 2001b; Kenter
and Hoffmann 2009), while others have not (Campbell
and Klotz 2007). Therefore, sugar beet cultivar may be a
contributing factor to sugar beet storage losses and
should be further evaluated.
Beyond production practices, storage losses may be
minimized by modifying sugar beet pile management.
Reducing damage to sugar beets or any other storage
roots, such as carrots and turnip, increases storability
and minimizes rots. For instance, mechanical damage
increases sugar beet respiration and significantly lowers
sucrose content over the storage period (Cole 1977).
However, there may be an opportunity to optimize the
method of removing sugar beets from storage to mini-
mize storage losses. In long-term storage piles, an outer
1 m layer of deteriorated sugar beets forms in response
to dehydration and freeze-thaw cycles. Akeson et al.
(1974) found that this outer rind contributes to con-
siderable recoverable sugar loss. In the standard pile
removal method, sugar beets are removed at ship-
ping from the face-end of the pile with large loaders.
An alternative is to remove sugar beets down the length
of the pile on each side using a EuroMaus†. With the
length-removal method, the rind does not form along
the length of the pile and may provide better overall pile
ventilation. Considering that the length-removal method
removes a larger area of the outer pile compared with
the standard end-removal method, sucrose losses may
be minimized by employing the new length-removal
method.
Developing methods to improve storage quality will
ultimately increase sucrose recovery in the processing
plant and thus profitability for the grower-owned co-
operative. Therefore, the objectives of this research were
to evaluate the influence of N fertilization, sugar beet
cultivar and pile management practices on sucrose losses
during storage in large outdoor piles.
MATERIALS AND METHODS
A study over three storage seasons was conducted to
determine the independent effect of N fertilization and
cultivar on sugar beet storage losses in commercial
production fields and at MSC’s Dover Piling Station
near Chatham in southwestern Ontario. Field studies
were conducted on a Brookston clay loam to silty clay
loam soil with 3.3 to 4.4% organic matter and pH of
130 CANADIAN JOURNAL OF PLANT SCIENCE
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6.8 to 7.4 (Table 1). Sites were in different fields each
year but were under the same production practices, with
field corn (Zea mays L.) as the previous crop. All
nutrients, other than N fertilization, were based on soil
testing and typical Ontario production practices. Typi-
cal pest control and other field operations were
followed. Air and soil temperature and precipitation
data were collected (Table 2). Sugar beets were seeded
on 28, 19, and 23 April 2006, 2007, and 2008, and 8 May
2009, respectively at 128 500 seeds ha
1
with 76 cm
between plant rows and seeds planted 10 cm apart. At
approximately 4 wk after seeding, stand counts from
2 m of the middle two rows were taken.
Nitrogen Trial
A randomized complete block design with four replica-
tions was used for the N trial with cultivars Crystal 271,
963 and 827RR in 2006, 2007, and 2008, respectively.
Plots were 8 m by 4.6 m or 6 rows wide. Ammonium
nitrate was applied in 2006 and 2007 but due to its
limited availability, calcium ammonium nitrate was
applied in 2008. Nitrogen fertilizer was hand broadcast
at planting at 0, 56, 112, 168 and 225 kg N ha
1
. The
influence of timing of N fertilizer application was
evaluated with split applications of 5656 and 84
84 kg N ha
1
. Ammonium nitrate was broadcasted by
hand with the first application preplant and the second
application on 6, 11 and 12 June 2006, 2007, and 2008,
respectively. At harvest, after collection of leaf and
crown tissue from six sugar beet plants, a commercial
mechanical topper removed sugar beet tops from the
entire N trial area. Approximately 6 m of the center two
rows were machine harvested with a single row har-
vester. Fresh weights were used to calculate marketable
yield.
For total N analysis at harvest, foliage and roots from
five sugar beets were weighed, sliced, and dried at 608C.
After determining dry weights, a representative sample
of dried plant tissue was ground in a Wiley mill with a
2 mm diameter opening mesh screen. Total N content
Table 1. Selected soil characteristics of sugar beet nitrogen fertilizer
experimental sites in Dover, Ontario, Canada, during 2006
2008
Characteristic
z
2006 2007 2008
pH 7.4 6.8 7.4
Soil texture Clay loam Clay loam Silty clay loam
sand:silt:clay (%) 33:30:37 24:45:31 7:57:36
OM (%) 4.4 3.9 3.3
Cation exchange capacity
(MEQ 100 g
1
)
38.9 28 27.3
Preplant nutrients (mg kg
1
)
Nitrate-N 11 9 12
Phosphorus 24 29 20
Potassium 171 241 148
Calcium 6184 4416 5944
Magnesium 765 495 406
z
Soil sample depth was 15 cm for all parameters except nitrate-N,
Table 2. Monthly average maximum and minimum temperature and total rainfall at Dover, Ontario, Canada, and the 30-yr mean. Temperature is presented in 8C and precipitation in mm
2006 2007 2008 2009 30 Year Mean
Month Tmax Tmin Precip Tmax Tmin Precip Tmax Tmin Precip Tmax Tmin Precip Tmax Tmin Precip
Jan. 4.3 1.6 81 1.2 5.3 52 1.5 6.2 26 4.2 15.4 11 1.2 8.0 28
Feb. 2.0 6.7 50 4.4 11.8 3 0.8 9.2 82 1.0 8.1 54 0.0 7.3 31
Mar. 7.0 3.4 101 7.7 2.0 24 3.1 4.9 58 7.3 4.3 110 5.5 2.6 50
Apr. 15.9 2.4 80 12.4 1.6 52 15.5 3.0 158 14.9 1.8 162 12.6 2.7 75
May 20.6 9.2 118 22.2 8.2 67 18.6 5.7 83 21.1 7.2 56 20.0 8.7 74
Jun. 24.8 12.8 68 27.9 13.0 26 25.9 15.2 120 24.0 12.4 103 25.1 14.1 85
Jul. 28.0 16.2 109 27.2 13.5 39 28.2 14.8 97 25.0 13.6 74 27.4 16.6 79
Aug. 26.8 13.8 84 26.8 14.3 124 27.4 12.3 153 25.2 15.0 129 26.3 15.8 85
Sep. 21.0 9.9 70 25.3 10.2 30 25.6 9.8 38 23.2 10.6 29 22.1 11.8 94
Oct. 14.1 3.9 123 20.4 8.7 11 17.2 2.0 114 13.9 4.6 78 15.2 6.1 65
Nov. 10.0 0.9 60 8.1 1.4 67 7.2 0.4 65 10.9 2.0 22 7.7 0.9 72
Dec. 5.1 0.7 70 0.9 5.4 80 0.6 7.6 61 1.2 4.7 58 1.4 4.5 49
VAN EERD ET AL. *PILE MANAGEMENT ON SUGAR BEET STORAGE 131
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in plant biomass was determined by dry combustion
method (Rutherford et al. 2008) using a LECO CN
determinator (Leco Corporation, St. Joseph, MI) at an
Ontario certified laboratory (A&L Canada Laborato-
ries Inc., London, ON). Percent total N content was
converted to kg N ha
1
based on root and shoot dry
weights.
Variety Trial
Sugar beets harvested from an industry-supported
Sugar Beet Advancement Variety Trial in 20072009
(Michigan State University 20072009) were used to
assess storage losses in large outdoor piles. Twelve, four,
and ten varieties were planted in 2007, 2008, and
2009, respectively, and reflect the industry transition to
Roundup Ready†varieties. Roundup Ready†varieties
were planted in 0, 60 and 98% of the Ontario and
Michigan sugar beet acreage in 2007, 2008, and 2009,
respectively. The cultivar trial was a randomized strip
trial with three or four replications. Strips were 4.6 m
(6 rows) wide by the length of the field, at least 330 m.
After mechanical harvest and transport to the piling
yard, random samples were collected as the sugar beets
passed over the pilers, in order to simulate normal
handling conditions.
Sugar Beet Storage and Quality
For N and cultivar trials, sugar beets from each plot
were randomly partitioned into five nylon mesh bags
with approximately 10 roots per bag. One sample was
analyzed for sucrose content and quality parameters at
harvest. Weights and root number were recorded and
the remaining four samples were placed into one of
four well-ventilated steel mesh containers. The 0.75 m
3
volume containers consisted of 5-mm diameter rods
spaced 5 cm apart. Once all samples were placed in the
appropriate containers, the cages were filled with loose
sugar beets and placed on top of approximately 0.6 m of
sugar beets in the middle of a large pile at MSC’s Dover
Piling Station (Chatham-Kent, ON). The containers
were buried with sugar beets by the pilers within 5 h.
The outdoor sugar beet pile was 305 m long by 60 m
wide by 5.5 m high. To aid in sample retrieval, a plastic
pipe extended out from each container to the edge of the
pile. The samples were removed from the outdoor pile at
approximately 50, 80 and 100 d after storage, except in
the 2009/2010 storage season where the last storage date
was 20 January 2010 with only 77 d of storage (Table 3).
The last retrieval date corresponded with the final day of
sugar beet storage at the Dover Piling Station.
To compare the effect of pile removal management on
storage quality, one container was placed in a different
pile, which was managed with the standard end-removal
method and retrieved on the final day of storage each
season. With the end-removal method, sugar beets were
taken from the face end (605.5 m) of the pile and
loaded into trailers for transportation to the sugar
refinery. With the new length-removal method, approxi-
mately 1.5 m of sugar beets was raked from along the
length of the pile (305 m) onto the ground and eleva-
ted, cleaned, and loaded into trailers with a modi-
fied EuroMaus†(ROPA-Fahrzeug und Maschinenbau
GmbH. Herrngiersdorf, Germany). Sugar beet removal
was from both sides of the pile for the length-removal
method. Both piles were not covered nor ventilated.
At harvest and each retrieval date, sampled sugar beets
were washed, weighed, and cut with a rasping circular
saw to obtain 1 L of brei (macerated root material). Brei
was frozen and shipped to MSC for analyses of sucrose
and quality parameters according to industry standards
(Carruthers and Oldfield 1961). Sucrose content was
determined by the polarimeter method (Halvorson et al.
1978), and clear juice purity (CJP), as well as brei
impurity amino-N were determined according to meth-
ods described by Last et al. (1976).
Recovery of sucrose in the processing factory was
estimated as recoverable white sucrose (RWS) per fresh
weight ton of sugar beets, and calculated as:
Grower income was calculated using the 2006, 2007, and
2008 MSC payment system (Wayne Martin, MSC,
personal communication). In 2006, grower income in
US dollars per fresh weight ton of sugar beets was
3.518(S 15.4), where Sis mean percent sucrose of
the cooperative. In 2007 and 2008, grower income in US
dollars per fresh weight ton of sugar beets was G
RWS
/
C
RWS
SPS, where G
RWS
RWS for each individual
grower, C
RWS
mean RWS of the cooperative and
SPSestimated selling price of sugar beets per fresh
RWS((%sucrose18:4)22)((1(60=(% CJP3:5)))=0:4)(Wayne Martin;MSC;personal communication):
Table 3. Sugar beet harvest date and length of storage in large outdoor
piles at Dover, Ontario, Canada, during three storage seasons from
2007
2010
Activity 20072008 20082009 20092010
Harvest 01 Nov. 28 Oct. 4 Nov.
Retrieval no. and month Days in storage
1. Dec. 49 48 40
2. Jan. 82 78 68
3. Feb. 104 100 77
132 CANADIAN JOURNAL OF PLANT SCIENCE
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weight ton. In 2007 and 2008, the cooperative mean was
264.5 and 272 RWS per fresh weight ton of sugar
beets, respectively, and the selling price was $35.00 and
$40.01 per fresh weight ton of sugar beets, respectively.
Thus, grower income per hectare was based not only
on yield but also quality. All economic parameters and
RWS were calculated on a fresh weight basis and data
converted to metric units for analyses and presentation.
Statistical Analysis
The N fertilizer rate responses for sugar beet yield and
quality parameters were fitted to linear and quadratic
models using PROC REG model in SAS (SAS Institute,
Inc. 2010). A paired t-test was used to compare the two
pile management methods for N and cultivar trials
separately. Each storage season of the cultivar trial was
analyzed separately due to the significant change in the
varieties tested and the number of entries from 2007 to
2009 in response to the industry’s move to glypho-
sate-tolerant sugar beet varieties. All other data were
subjected to analysis of variance using type I sums of
squares in PROC MIXED model in SAS (SAS Insti-
tute, Inc. 2010), with year as a random effect and N
application or cultivar and retrieval date as fixed effects.
For all data sets, residual plots and the Shapiro-Wilk
normality test were used to confirm analysis of variance
assumptions. Data, where necessary, were subjected to a
logarithmic transformation and results presented in the
original scale. Data were pooled when there was no
effect or interaction. Means separation was determined
using Tukey-Kramer multiple comparison procedure.
The type I error (a) was set at 0.05.
RESULTS AND DISCUSSION
Growing and Storage Season Conditions
The 2006 growing season was cooler than the 30 yr
climatic mean with near typical precipitation April
through August but 20 and 100% more rainfall than
climatic norms in September and October, respectively
(Table 2). Thus, sugar beet harvest was challenging.
The excessive rainfall and poor field conditions resulted
in an inability to harvest all treatments and an industry
decision to forego the storage experiment for the 2006
2007 season. In the 2007 and 2009 growing seasons,
drought conditions occurred with 25% less rainfall
than the 30-yr mean. Above average air temperatures
in 2007 and dry soil conditions both years caused sugar
beet drought stress, as indicated by lower yields and
higher sucrose content. The 2008 growing season was
ideal with near-average temperature and precipitation.
Thus, diverse growing season conditions among years
were observed. Sugar beets in all experimental sites
were grown without irrigation as is typical for the
region. Storage seasons for 20072008, 20082009 and
20092010 were ideal, with relatively constant tempera-
tures and most precipitation as snow rather than rain.
Nitrogen Fertilizer Effect on Sugar Beet Yield and
Quality
In the N trial, mean sugar beet yields were 93.6, 68.9,
and 92.4 Mg ha
1
with 18.1, 21.8, and 19.5% sucrose
content for 2006, 2007, and 2008, respectively (Fig. 1).
Yields and sucrose contents were representative of the
industry in the region and comparable with the 2006
2008 USDA reported yield of 55.8 Mg ha
1
(USDA
2010a).
In all 3 yr, N fertilizer was negatively related to %
sucrose, RWS, and % CJP, but positively related to the
contaminant amino-N (Fig. 1). Thus, overall sugar beet
quality declined with increased fertilizer N application.
These results were expected, as a negative correlation
between N fertilization and sucrose concentration/con-
tent has been well established (Eslami et al. 1988; Bilbao
et al. 2004; Stevens et al. 2008). Clear juice purity was in
agreement with previous research but sucrose content
was higher than observed by Eslami et al. (1988).
However, the observed high sucrose content in the N
and cultivar trials was typical of sugar beets grown in
southwestern Ontario (Michigan State University 2007
2009).
Based on MSC payments to growers, which were
based on sugar beet root yield and quality, the most
economical rate of N was approximately 112 kg N ha
1
in 2006 and 2008 (Fig. 1). The most economical rate of
N in 2007 was significantly higher at approximately
168 kg N ha
1
due to drought conditions, which
lowered root yield, but increased sucrose content.
Optimal N rates were in agreement with results reported
from the Great Plains growing region (Lauer 1994;
Eckhoff 1995) and Ontario grower practices as indicated
by a 2009 survey of sugar beet producers (Van Eerd and
Zandstra 2010). The observed yield response to drought
conditions was comparable with Lauer (1994), who
found lower sugar beet root yields with insufficient
irrigation in Wyoming, USA. Because the drought
conditions of 2007 can be considered atypical, research
results suggest 112 kg N ha
1
as the recommended rate
of N fertilizer for sugar beets.
For all yield and quality parameters, the split N
applications of 5656 and 8484 kg N ha
1
were not
statistically different from the preplant N application
of the same total N amount (112 and 168 kg N ha
1
)
(Fig. 1). Similarly, split N application has had no effect
on impurities or yield in past research (Eckhoff 1995;
Wiesler et al. 2002). The addition of N fertilizer mid-
season does not replace yield lost during earlier growth
stages (Carter and Traveller 1981), which may explain
why split N fertilizer application seemed ineffective in
increasing root yield. Draycott and Christenson (2003)
observed that during the 60 d period from sugar beet
emergence to a leaf area index of 3, N was rapidly taken
up to meet the needs of plant growth. In the present
study, fertilizer application in the split N treatments
occurred within B60 d of each other, during the rapid
growth period. The lack of differences between N
VAN EERD ET AL. *PILE MANAGEMENT ON SUGAR BEET STORAGE 133
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preplant and split applications suggests there was ade-
quate soil mineral N prior to the second N application.
Nitrogen Fertilizer Effect on Sugar Beet Storage
Nitrogen fertilizer rate was positively correlated to
harvested sugar beet N concentration (%) in 2 of 3 yr
(2006 and 2008) and to N content (kg N ha
1
) in all 3 yr
(Fig. 2). The drought conditions likely contributed to the
lack of correlation between N rate and N concentration
in 2007. Thus, there were differences in sugar beet N
content among treatments upon entering storage in large
outdoor piles (Fig. 2).
As expected, sugar beet quality was higher at harvest
and lower after storage in February (Table 4). For all
parameters measured, there was no interaction between
N rate and retrieval date, despite the fact that total N
concentration and content in sugar beet roots were
lower in the zero N control (Fig. 2). Although sugar beet
quality tended to be lower with the split application of N
compared with the same amount applied preplant, there
were few significant differences. This result indicates
that across the N rates and timings tested, N did not
influence sugar beet storability over the 100 d period.
In must be noted that conditions during all three storage
Y Data
N fertilizer applied (kg N ha–1)
0 50 100 150 200 250
Root yield (tonne ha–1)
0
20
40
60
80
100
r2= 0.6227***
r2= 0.4187*
r2= 0.5504***
56+5684+84
Y Data
0 50 100 150 200 250
Clear juice purity (%)
93
94
95
96
97
98
2006 y = 7.06 + 0.0287 r = 0.8272***
2007 y = 3.97 + 0.00728 r = 0.5318*
2008 y = 5.77 + 0.0274 r =0.7508***
2007 y=95.2+0.0047x-0.000028x2r2 = 0.1558+
2006 y=95.8-0.00018x-0.000017x2r2 =0.6695***
2008 y=97.4+0.00017x-0.000041x2r2 = 0.5127***
N fertilizer (kg N ha–1)
84+84 56+56
Y Data
N fertilizer applied (kg N ha–1)
0 50 100 150 200 250
Sucrose content (%)
16
18
20
22
24
2006 y = 7.06 + 0.0287 r = 0.8272***
2007 y = 3.97 + 0.00728 r = 0.5318*
2007 y=22.4-0.00363x
2006 y=19.2+0.000318x-0.0000216x2r2= 0.5521**
2008 y=19.9+0.00555x-0.0000554x2r2 = 0.6629***
r2 = 0.4478ns
84+84 56+56
Y Data
0 50 100 150 200 250
Amino-N (mg100g–1 sugar)
0
20
40
60
80
100
120
140
84+84 56+56
2007 y=39.7+0.0728x r² = 0.2825*
2006 y=70.6+0.287x r² = 0.6843***
2008 y=57.8+0.274x r² = 0.5637***
Y Data
N fertilizer a
pp
lied
(
k
g
N ha–1
)
0 50 100 150 200 250
Recoverable white sucrose (kg Mg–1)
80
100
120
140
160
84+84 56+56
2006 y=120-0.0394x
2007 y=144-0.0590x
r2 = 0.6104**
2008 y=128+0.0219x-0.000402x2r2= 0.7152**
r2 = 0.4791***
Y Data
0 50 100 150 200 250
Income ($ ha–1)
1000
2000
3000
4000
5000
6000
r2 = 0.7335***
r2 = 0.4519**
r2 = 0.3364**
N fertilizer
(
k
g
N ha-1
)
84+84 56+56
2006 y=87.5+10.2x -0.000771x2
2007 y=61.6–0.294x+0.00432x2-0.0000121x3
2008 y=86.0+0.107x-0.000262x2
2006 y =5070+11.7x -0.0532x2
2008 y =3920+6.91x-0.031x2
2007 y=2640-7.17x+0.127x2-0.000370x3
Fig. 1. At harvest in 2006 (k), 2007 (%), and 2008 (j), sugar beet root yield and quality response to (calcium) ammonium nitrate
fertilizer broadcast incorporated preplant or preplant and in-season before row closure at 5656 and 8484, respectively. Bars
represent SE of means. NS,
, *, **, *** Nonsignificant or significant at P50.1, 0.05, 0.01, or 0.001, respectively (n]12).
134 CANADIAN JOURNAL OF PLANT SCIENCE
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seasons were excellent (Table 2; Wayne Martin, MSC,
personal communication), as no rot (data not shown)
and very little weight loss were observed (Table 4).
The effect of N fertility under less than ideal storage
conditions is unknown.
Cultivar Effect on Sugar Beet Storage
In each storage season, differences in sucrose content
were noted among cultivars, although significant differ-
ences in RWS were observed only in the first two
seasons (Tables 57). There were no differences in
percent weight loss or CJP during storage among
varieties in any year (Tables 57). Overall sugar beet
quality decreased over the storage period as evident by
decreases in % sucrose, % CJP, and RWS (Tables 57).
Similar to the N fertility storage trial (Table 4), in the
20072008 and 20082009 storage season, weight loss
was significantly greater in January compared with
December and February retrieval dates (Tables 5 and
6), likely due to lower temperatures and precipitation
in January (Table 2). For all parameters, no cultivar
by storage date interaction was found in any of the
storage seasons (Tables 57), indicating that, in this
study, cultivars did not differ in storability in large
piles, which was consistent with the N fertility storage
trial.
Sucrose losses over the storage period were expected
(Kenter and Hoffmann 2009) and differences in storage
characteristics among sugar beet cultivars were consis-
tent with some (Martin et al. 2001b; Kenter and
Hoffmann 2009), but not other studies (Campbell and
Klotz 2007). Differences among sugar beet cultivars
in concentrations of impurity factors, such as sodium,
potassium, amino-N and betaine, were observed after
100 d of pile storage (Martin et al. 2001b). Addition-
ally, amino-N, dry matter, sucrose, invert sucrose and
raffinose concentrations differed between two cultivars
after pile storage (Kenter and Hoffmann 2009). It has
therefore been suggested that genetic variability for
storability may exist (Kenter and Hoffmann 2009) but
cultivar screening under controlled storage conditions
selects for good storage characteristics of commercially
available cultivars, which ultimately may decrease the
likelihood of observing a cultivar by retrieval date
interaction in large outdoor piles.
Many sugar beet storage studies involve measurement
of respiration in vitro (Cole 1977; Wyse et al. 1978;
Wyse and Peterson 1979). Recent work has suggested
that respiration is influenced more by environment and
environment by genotype interactions than genotype
alone (Campbell and Klotz 2007). Similarly, Kenter and
Hoffmann (2009) observed that although sugar beet
quality declined over 110 d of storage, there was a
difference in sugar beet quality between varieties when
the sugar beets were stored at 78C compared with 208C.
In our study, the outdoor storage conditions over the
three storage seasons were ideal with minimal fluctua-
tions in temperature (Table 2). The influence of cultivar
on sugar beet storability may be more pronounced
under unfavorable storage conditions (Martin et al.
2001b). Regardless, the lack of cultivar by storage date
interaction for all storage quality parameters measured
in all three storage seasons suggests that growers do not
need to modify their cultivar selection to minimize
storage losses.
Pile Management Effect on Sugar Beet Storage
In both trials in all three storage seasons, sucrose
concentration (%), RWS content, and grower income
were significantly higher with the new length-removal
technique compared with the standard end-removal
method (Table 8). Likewise, percent CJP was numeri-
cally or significantly higher with the length-removal
method compared with the end-removal method. In
contrast, the length-removal method tended to increase
the impurity amino-N (data not shown) compared with
the standard end-removal method.
Overall, sugar beets from both N and cultivar trials
had significantly better quality after up to 104 d of
split
Y Data
N fertilizer (k
g
N ha–1)
0 50 100 150 200 250
N content (kg N ha
–1
)
0
50
100
150
200
2006 y=114+0.683x-0.00232x² r ²=0.4788*
2007 y=88.3+0.142x r ²=0.4643*
2008 y=90.2+0.273x r ²=0.4130*
split
Y Data
0 50 100 150 200 250
N concentration (%)
0.0
0.2
0.4
0.6
0.8
1.0
2006 y=0.549+0.000610x r ²=0.3007+
2007 y=0.518+0.000322x r ²=0.2028NS
2008 y = 0.398+0.00103x r ²=0.4183*
A
B
Fig. 2. At harvest in 2006 (k), 2007 (%), and 2008 (j), sugar
beet root nitrogen (N) accumulation expressed as percent
nitrogen concentration (A) and on a dry weight basis (B)
in response to preplant broadcast incorporated (calcium)
ammonium nitrate fertilizer. The split treatment was two
applications at 8484 kg N ha
1
applied preplant and in-
season before row closure, respectively. Bars representing SE
of means. NS,
, * Nonsignificant or significant at P50.1 or
0.05, respectively (n12).
VAN EERD ET AL. *PILE MANAGEMENT ON SUGAR BEET STORAGE 135
Can. J. Plant Sci. Downloaded from pubs.aic.ca by 54.152.109.166 on 09/13/15
For personal use only.
storage when piles were recovered by removing sugar
beets along the length of the pile compared with the
industry standard method of removing sugar beets from
the face-end of the pile. Although conditions during
all three storage seasons were ideal, one would expect
this trend to hold true under more challenging storage
conditions. Past research on sugar loss in large un-
covered piles has found that 40% of the recoverable
sugar loss occurred in the outer 60 cm of the pile, despite
the outer rim representing only 17% of pile volume
(Akeson et al. 1974). Thus, one would expect increased
sucrose recovery with the new length-recovery method,
Table 4. Impact of N fertilizer and length of storage on sugar beet weight loss and quality during 2007
2008 and 2008
2009 storage seasons in large
outdoor piles at Dover, Ontario, Canada
z
N Applied
y
(kg N ha
1
) Weight loss
x
(%) Clear juice purity (%) Sucrose (%) Recoverable white sucrose (kg Mg
1
) Income ($ ha
1
)
0 4.1 95.9a20.5a128a3210c
54 3.9 95.9a20.5a127a3250c
112 3.7 95.6ab 20.3ab 126ab 3370abc
168 4.2 95.0b19.7bc 120bc 3610a
225 3.6 95.3ab 19.7bc 121bc 3520ab
8484 3.3 95.1b19.2c118c3280cb
5656 3.3 95.9a20.1ab 125ab 3380abc
Storage date
Harvest 95.8a20.7a129a3510a
Dec. 3.3b95.6a19.6c121b3320bc
Jan. 3.3b96.0a20.2b126a3450ab
Feb. 4.6a94.7b19.5c119b3230c
Fixed effects ----------------------------------------------------------------------- Pvalue-----------------------------------------------------------------------
N 0.8449 B0.0001 B0.0001 B0.0001 B0.0001
Storage date 0.017 B0.0001 B0.0001 B0.0001 B0.0001
Ndate 0.8467 0.4319 0.9326 0.8002 0.9918
z
Data were pooled means of two storage season with four replicates each. Within each column, means for N or date with a different letter indicate a
statistical difference (P50.05) based on Tukey-Kramer multiple range test.
y
(Calcium) Ammonium nitrate was broadcast incorporated preplant or preplant and in-season before row closure at 8484 or 5656 kg N ha
1
,
respectively.
Table 5. Impact of cultivar and storage duration on sugar beet weight
loss and quality during 2007
2008 storage season in large outdoor piles
at Dover, Ontario, Canada
z
Cultivar
Weight
loss
y
(%)
Clear juice
purity (%)
Sucrose
(%)
Recoverable
white sucrose
(kg Mg
1
)
2771 RZ 2.5 94.9 19.7ab 121bc
79 RZ 1.8 94.9 19.4b118c
80 RZ 2.0 94.4 18.8c113d
B-5411 R 3.1 95.3 20.2a124a
B-5451 2.3 94.7 19.7ab 120bc
B-5833 R 3.2 95.1 19.3b119c
B-5930 R 2.6 94.9 20.1a123ab
C-271 2.9 94.7 19.8ab 120bcd
C-355 2.3 95.0 19.6b121abc
C-963 2.5 94.9 19.8ab 121abc
R-442 2.7 94.9 19.5b119bc
R-509 2.8 95.1 19.8ab 121abc
Storage date
Harvest 94.9 19.9a121bc
Dec. 1.4c95.1 19.9a118c
Jan. 4.1a94.7 19.5b113d
Feb. 2.6b94.7 19.4b124a
Fixed Effects ----------------------------- Pvalue -----------------------------
Cultivar 0.1219 0.3059 0.0001 0.0002
Storage
date
B0.0001 0.1198 0.0011 0.0007
Cultivar
date
0.4035 0.0658 0.4948 0.5599
z
Data were means of three replicates. Within each column, means for
variety or date with a different letter indicate a statistical difference
(P50.05) based on Tukey-Kramer multiple range test.
y
Weight loss was relative to beet weight at harvest.
Table 6. Impact of cultivar and storage duration on sugar beet weight
loss and quality during 2008
2009 storage season in large outdoor piles
at Dover, Ontario, Canada
z
Cultivar
Weight
loss
y
(%)
Clear juice
purity (%)
Sucrose
(%)
Recoverable white
sucrose (kg Mg
1
)
C-RR827 3.2 96.0 20.0a125a
HM-27RR 3.4 96.1 19.6b123b
HM-28RR 3.3 96.1 19.6b123b
HM-29RR 3.7 96.2 19.8b124ab
Storage date
Harvest 96.6a19.8 125a
Dec. 2.2c96.0b19.8 123ab
Jan. 4.5a95.7b19.6 122b
Feb. 3.6b96.1b19.8 124a
Fixed
Effects
----------------------------- Pvalue-----------------------------
Cultivar 0.6496 0.9752 0.0001 0.0232
Storage
date
0.0001 0.0002 0.3989 0.0138
Cultivar
date
0.6736 0.0699 0.6501 0.4780
z
Data were means of four replicates. Within each column, means for
cultivar or date with a different letter indicate a statistical difference
(P50.05) based on Tukey-Kramer multiple range test.
y
Weight loss was relative to beet weight at harvest.
136 CANADIAN JOURNAL OF PLANT SCIENCE
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because it removes a larger area of the outer rim of the
pile on both sides compared with the end-removal
method.
When sugar beets were removed along the length of
the pile, a rind of degraded sugar beets does not form
along the 300 m length of pile. Preventing the formation
of a rind is speculated to improve pile ventilation and
overall sugar beet quality during storage. This may be
beneficial for two reasons. First, fewer degraded sugar
beets are shipped to the factory for processing with the
new length-removal method, whereas the standard
end-removal method includes degraded sugar beets
thereby lowering processing efficiency. Second, air
flow and temperature control are important in main-
taining sugar beet sucrose levels in storage piles (Bugbee
1993); thus removing the rind may provide better
ventilation and improve storage conditions. Considering
that the sugar beet samples were placed in the middle of
the pile and not within the rind, the length-removal
method clearly resulted in higher quality beets (Table 8)
likely due to better storage conditions, which may be
attributed to better ventilation than the end-removal
method.
Higher quality sugar beets from the length-removal
method may also be due to greater sugar beet weight
loss when compared with sugar beets managed using the
end-removal method (Table 8). The greater weight
loss was likely due to greater ventilation of low humidity
air in the length-removal pile. Lighter sugar beets,
due to moisture loss, will reduce the cost of shipping
sugar beets from the piling yard to the processing plant
and may lower sucrose production costs by lowering the
amount of water that needs to be removed during
processing.
Other possible efficiencies with the length-removal
method of pile management may result from the use
of a EuroMaus†. The EuroMaus†is a self-propelled
machine, which lifts, cleans, and elevates sugar beets
into trailers for shipment to the processing plant. It was
developed in Europe to load sugar beets from short-
term storage piles (clamps) in grower’s fields. Effective
cleaning of the sugar beets results in less dirt being
shipped, which saves on shipping costs and reduces the
amount of beet cleaning needed at the factory before
sucrose extraction.
Although the results show that growers do not have to
modify their N management practices or select speci-
fic varieties to maintain storage quality, they indicate
that the length-removal method of pile manage-
ment improves storability compared with the standard
Table 7. Impact of cultivar and storage duration on sugar beet weight
loss and quality during 2009
2010 storage season in large outdoor piles
at Dover, Ontario, Canada
z
Cultivar
Weight
loss
y
(%)
Clear juice
purity (%)
Sucrose
(%)
Recoverable
white sucrose
(kg Mg
1
)
B-17RR32 1.7 94.6 19.5b115
B-17RR62 1.7 94.0 19.8ab 118
C-RR824 1.5 95.5 19.5b121
C-RR827 1.9 94.8 19.8ab 120
C-RR827
x
1.8 94.8 20.1a123
HM-27RR 1.6 94.8 20.1a123
HM-28RR 1.6 94.3 19.5b114
HM-29RR 1.8 95.1 19.6ab 120
HM-42RR 1.4 95.0 20.0a123
HM-50RR 1.4 94.5 20.1a122
HM-50RR
x
1.2 94.6 19.7ab 119
SX-1260RR 2.1 94.3 19.8ab 119
Storage date
Harvest 95.5a19.9a123a
Dec. 1.6b94.3c19.6b118bc
Jan. 1.1c94.4c20.0a121ab
Feb. 2.2a94.5b19.6b116c
Fixed
Effects
----------------------------- Pvalue -----------------------------
Cultivar 0.5584 0.2386 0.0278 0.0546
Storage
date
0.0001 0.0001 0.0049 0.0009
Cultivar
date
0.3087 0.7303 0.1989 0.5023
z
Data were means of three replicates. Within each column, means for
cultivar or date with a different letter indicate a statistical difference
(P50.05) based on Tukey-Kramer multiple range test.
y
Weight loss was relative to beet weight at harvest.
x
Denotes cultivars that received a single application of azoxystrobin
(Quadris†) at the 68 leaf stage.
Table 8. Impact of sugar beet removal method on sugar beet weight loss and quality after 77 to 104 d of storage in large outdoor piles at Dover, Ontario,
Canada, during three storage seasons from 2007
2010
Trial Removal method Weight loss
y
(%) Sucrose (%) Clear juice purity (%) Recoverable white sucrose (kg Mg
1
) Income ($ ha
1
)
Nitrogen End 2.7 19.3 94.5 121 2080
Length 3.9 19.7 94.7 123 3190
Pvalue B0.0001 0.0067 0.0926 0.0113 B0.0001
Cultivar End 2.4 19.2 92.8 116
Length 3.0 19.6 94.8 123
Pvalue 0.0054 0.0016 B0.0001 0.0002
z
Data were means of two or three storage season with four or three replicates each for the nitrogen and cultivar trial, respectively. Statistical
significance (P50.05) was based on a one-tail paired t-test.
y
Weight loss was relative to beet weight at harvest.
VAN EERD ET AL. *PILE MANAGEMENT ON SUGAR BEET STORAGE 137
Can. J. Plant Sci. Downloaded from pubs.aic.ca by 54.152.109.166 on 09/13/15
For personal use only.
end-removal method. Based on an estimated 2.8 million
Mg of sugar beets stored by MSC and the mean
difference of 5 kg of recoverable white sucrose Mg
1
between the two pile management methods, switching to
the length-removal method would increase white sucrose
recovery by 14 000 Mg. Not all sugar beets are stored for
the full season; therefore, effects would be expected to be
less for shorter storage durations. Based on the 2007
2010 average sucrose selling price of $0.42 kg
1
(USDA
2010b), if one considers a conservative 7000 Mg in-
crease in white sucrose by switching to the length-
removal method, this would amount to an increase
in estimated revenue of $2.9 million and $10 million
for the MSC cooperative and the sugar beet industry in
Alberta, respectively. Thus, implementing the length-
removal method of pile management has the potential to
improve overall sugar beet processing efficiency and
profitability.
ACKNOWLEDGEMENTS
Funding for this project was provided in part by Agri-
culture and Agri-Food Canada through the Agricultural
Adaptation Council and the Alberta Agriculture and
Food Program. Other sources of funding include the
Ontario Sugarbeet Growers Association, and Ontario
Ministry of Agriculture, Food and Rural Affairs. In-
kind analyses were provided by A&L Laboratories
Canada Inc. and Michigan Sugar Company Inc. and
weather data from Weather Innovations Incorporated
(WIN). The authors are especially grateful to Brian
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