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Table 4. Foliar mineral concentrations (dry weight basis) of ‘Starkrim son Delicious’ trees on various rootstocks (overall means for
1984 through 198 6).z
Interstock/
rootstock
N
(%)
p
(%)
K
(%)
Ca
(%)
Mg
(%)
Mn Zn
(p-g'g~ ')
M.27 EMLA 2.74 a 0.18 a 1.30 a 1.2 9 a 0.39 a 126 a 67 a
P.2/K A313 2.58 b 0.19 a 1.36 a 1.01 b 0.36 a 52 c 58 b
P.22/KA3 13 2.57 b 0.19 a 1.2 9 a 1.11 b 0.37 a 66 b 64 ab
C.6/K A31 3 2.62 b 0 .19 a 1.39 a 1.08 b 0. 36 a 73 b 61 ab
zMean separation within columns by Du ncan’s New Multiple Range T est (p = 0 .05). Each data value is the mean of 21 observatio ns.
Liter ature Cited
1. Abdalla, O .A ., H. Khatam ian, and N.W .
Miles. 1982. Effect of rootstock and inter
stems on com position of ‘De licious’ apple
leaves. J. A mer. Soc. Hort. Sci. 107:730-
733.
2. Autio , W .R. and F .W . Southw ick. 1986.
The effe cts of rootstock and root-interstem
comb inatio ns on g rowth, productiv ity, and
ancho rage o f a spur and stan dard strain of
Delicious apple tree. Fruit Var. J. 4 0:12 8-
133.
3. Awad, M.M . and A .L. K enworthy . 1963.
Clonal rootstock, scion var iety, and time of
sampli ng influences in apple leaf composi
tion. Proc. Amer. Soc. Hort. Sci. 83:68-73 .
4. Czynczyk, A. and S.W . Zagaja. 1984. Eval
uation of growth and cropping of apple trees
grafted on dwarf rootstocks and interstems.
Compact Fruit Tree 17:3 7-49.
5. Duncan, D.B. 1955. M ultiple range and
multiple F tests. Biometrics 11 :1-42 .
6. Ferre e, D.C. and R .F. Carls on. 1987. Apple
rootstocks, p. 10 7-1 43 . In: R .C. Rom and
R.F . Carlson (eds.) . Rootstocks for fruit
crops. Wiley, New York.
7. Hewetson, F.N . 1942. Growth and yield of
Steele Red apple trees as influ enced by the
use of variou s dou ble-w orked interstocks.
Proc. Am er. Soc . Hort. Sci. 40:264-2 68 .
8. Hewe tson, F.N. 1944. Growth and yield of
McIntosh apple trees as in fluenced by the
use of various intermediate stem pieces. Proc.
Amer. Soc. Hort. Sci. 45 :18 1- 18 6.
9. Lockard, R. G. 1976. Effect o f apple root
stocks and length and type of interstock on
leaf nutrient levels. J. Hort. Sci. 51 :289—
296.
10. Lord, W .J. , D .W . G reene, R .A. Damon,
Jr. , and J.H. Baker. 1985. Effects of stem-
piece and rootstock combinations on growth,
leaf mineral con centrations, yield , and fruit
quality of ‘Emp ire’ apple trees. J. Amer.
Soc. Hort. Sci. 110:42 2-4 25.
11. Meado r, D .B. 1979. Performance of apple
cultivars on in terste ms C-6 and C-52. Com
pact Fruit Tree 12: 64-66 .
12. NC-140. 198 7. Growth and production of
‘Starkspur Supreme De licious’ on 9 root
stocks in the NC-14 0 cooperative planting.
Fruit Var. J. 41:31 -3 9.
13. Norton, R.L. 1983. Interstems: Advantages,
problems, and vario us interactions. Com
pact Fruit Tree 16:8 3-88.
14. Poling, E.B. and G .H. Oberly. 1979. Effect
of roo tstock on m ineral composition of apple
leaves. J. Amer. Soc . Hort. Sci. 104 :79 9-
801.
15. Roach, W.A. 1947. The role of min eral nu
trition in the rootstock-scion ef fect. Annu.
Rpt. E. Mailing Res. Sta. for 1946 :88 -90 .
16. SAS Inst itute. 1985. SA S/ST AT guide for
personal computers. SAS Institute, Cary,
N.C .
17. Shelton, J.E . and D.C . Zeiger. 1970. Dis
tribution of manganese54 in ‘Delicious ’ ap
ple trees in relation to the occurrence of
internal bark necrosis (IBN). J. Amer. Soc.
Hort. Sci. 9 5:758 -76 2.
18. Tukey, R.B ., R. Langston, and R.A. Cline.
1962. Influence o f rootstock, bodystock, and
interstock on the nutrient content o f apple fo-
HortSci en c e 2 3( 6):985-988. 1988.
Proponents of trickle irrigation contend that
trickle irrigation, because of the frequency
of watering inherent in this system, results
in a constant high soil moisture level that is
nonlim iting to crop productivity. However,
most studies comparing sprinkler and trickle
irrigation have reported similar yields o f var
ious vegetable crops produced by the two
systems (2, 7, 12). Nevertheless, slight dif
ferences in soil matric potential at even a
relatively high level of soil moisture can re
sult in marked differences in vegetable growth
and yield (1, 3, 8, 10, 12). In spite of the
large impact that small differences in soil
moistu re can have on plant growth and yield ,
Received for pu blication 19 Aug. 1987. Paper No.
849, Dept, of Vegetable Crops, Cornell Univ. The
cost of publish ing this paper w as defrayed in part
by the payment of page charges. Under postal reg
ulations, this paper therefore must be hereby marked
advertisement solely to indicate this fact.
Curre nt address: Seabrook B ros. & Sons, Inc.,
Seabrook, NJ 08302.
liage. Proc. Amer. Soc. Hort. Sci. 80:7 3-78 .
19. Whitfield, A .B. 1964. The effects of stock
and scion on the mineral composition of ap
ple leaves. Annu. Rpt. E. Mailing Res. Sta.
for 1963:107-109.
many irrigation studies do not use soil matric
potential as the basis for irrigation schedul
ing.
We more fully assessed the potential ad
vantages of trickle irrigation for vegetable
production in a humid area by exam ining
frequency of irrigation and com parin g trickle
with sprinkler irrigation for bell pepper pro
duction using soil matric potential as the ba
sis for irrigation. Integrated into the study
were cultural practices common to pepper
production that are often used in conjunction
with trickle irrigation: black poly ethylene
mulch was compared with bare soil and raised
beds were compared with level ground. Black
plastic mulch is frequently used to conserve
soil moisture, increase soil temperature, and
control weeds (5). Raised beds are com
monly used in pepper production to improve
soil drainage and decrease disease incidence.
Irrigation studies were conducted during
Summer 1985 at Cornell Univ ersity’s Long
Island Horticultural Research Laboratory in
Riverhead, N .Y . Bell peppers were grown
Influence of Plastic Mulch and Type
and Frequency o f Irrigation on
Growth and Yield of Bell Pepper
Joseph E. VanDerwerken1 and Darlene Wilcox-Lee
Department of Vegetable Crops, Long Island Horticultural Research
Laboratory, Cornell University, 39 Sound Avenue, Riverhead, NY 11901
Add itiona l index words. Soil moisture, Capsicum annuum, trickle, sprinkler
Abstract. A field study was designed to evaluate the effects of various irrigation meth
ods, raised beds, and plastic mulch on yield and fruit quality of bell pepper (Capsicum
annuum L.) Irrigation was scheduled on the basis of soil matric potential and monitored
by Hg manometer tensiometers and soil moisture blocks. Trickle-irrigated plots were
watered at soil matric potentials of —0.025 and —0.075 MPa, and sprinkled plots at
— 0.075 MPa. The combination of black polyethylene mulch and irrigation produced
maximum yields, but frequency of irrigation had little effect on yield when peppers
were mulched. High frequency trickle irrigation (irrigated 15 x ) and trickle irrigation
of a lesser frequency (irrigated 5 x ) resulted in similar yields when peppers were
mulched. The use of mulch without irrigation had a large effect on yield: yields from
plots that were mulched but not irrigated were similar to yields from plots that were
sprinkler-irrigated but not mulched. The percentage of marketable fruit was substan
tially reduced in the absence of irrigation or mulch, because o f the high incidence of
both solar injury and blossom-end rot.
Table 1. Effects of type and frequenc y of irrigation and mulch on early flowering , early and total yi elds , and individual fruit weigh t
of ‘Calwonde r’ pepper.
______________________________
____
_____________
_________________________________
Early4 T otal x
Flowersy yield yield wt/fruit
Irrigation Mu lch (No./plant) (t- ha-1) ( t- h a -1) (g)
Trickle 15 x Yes 6.9 10.8 40.4 121
Trickle 5 x Yes 6.5 11.9 42.6 128
Sprinkler Yes 6.4 11.1 41.3 126
Sprinkler No 4.4 8.7 3 6.7 129
No irrigation Yes 6.7 10.2 38.3 121
No irrigation
Significance
No 4.3 3.2 24.1 94
Trickle 15 x /mulch > trickle 5 x /mulch NS NS NS NS
Trickle/mulch > sprin kler/m ulch NS NS NS NS
Sprinkler/m ulch >sp rinkler/no mulch * * * * ** NS
Sprinkler/m ulch > no. irrigation/no mulch NS NS *NS
Sprinkler/no mulch > no. irrigation/no. mulch NS * ** ** *
No irrigation/mulch > no. irrigation/no. mulch * ** * * * * *
Main effect sprink ler NS na na na
Main effect mulch * *na na na
Sprinkler x mulch NS * * * ** *
z Flowers per plant at anthesis.
y Cumulative marketab le and unmarketa ble fruit harvested through 16 Aug.
x Cumu lative marketable and unm arketable fruit harvested through 10 Sept.
ns ,*.** jq ot significant, significant at 5% , signific ant at 1 %, respectively; na = not applicab le since interac tion was highly significant
for these parameters.
on a Riverhead sandy loam soil. Fertilizer
was broadcast and incorporated before trans
planting 6-week-old transplants, at N, P, and
K rates o f 110, 100, and 90 k g-h a -1, re
spectively. Nitrogen was applied at 30 kg-ha~l
by spreading along the edge of the plastic
mulch about 2 weeks after transplanting.
Appropriate pest control measures were taken
throughout the season. Where required, raised
beds (0 .90 m wide and 0.12 m high) were
shaped mechanically.
Black polyethylene mulch (1.20 m wide
and 0.050 mm thick), underlaid with trickle
irrigation hose, was installed before trans
pla nting. A 0.4 -m m biw all drip tu b in g
(Chapin Watermatics, Watertown, N.Y.) was
used. A pressure regulator and four pressure
gauges in the irrigation system facilitated
monitoring of water pressure and increased
the accuracy of treatment applications. Shut
off valves for each plot allowed independent
treatment applications.
Plots were separated by a 2-m buffer zone
to limit the effects of neighboring sprinkler
treatments and water movement between
plots. Trickle or sprinkler irrigation lines were
centered in the middle of double rows of
plants in irrigated plots. Disregarding the wide
buffer zone between plots, a double row
configuration with plant spacing of 0.30 x
0.45 m equalled a population of 36,000 plants/
ha. Plots were 7.5 x 1.4 m and contained
50 plants.
Soil matric potential was monitored at about
8 a m , 6 days per week by Hg manometer
tensiometers (0.1 MPa standard design as
sembly, no. 655X1-B1M1, Soil Moisture
Equipment Co., Santa Barbara, Calif.) in the
irrigated plots and soil moisture blocks (no.
52 0 1 , meter n o. 5 9 10A, So il M ois tu re
Equipment Co.) in the unirrigated plots. Six
to ten measurements of soil matric potential
in the plant root zone at a depth of 0.15 m
were averaged for each treatment or subplot
treatment to schedule irrigation. Irrigation was
applied when the soil matric potential reached
a minimum of - 0 .0 2 5 or -0 .0 7 5 MPa.
There was an unirrigate d treatment as well.
Before initiation of irrigation treatments,
a relationship was established between soil
matric potential and mass soil w ater content
by means of pressure plate extraction (15 bar
cerami c plate ex trac to r, no . 1500, Soil
Moisture Equip ment Co.). Based upon this
soil moisture characteristic curve, the rate of
wate r delivery and the period of time for
each irri gati on w ere c alcu la te d for each
treatment to restore soil moisture to field ca
pacity (about - 0 .0 1 MPa soil matric poten
tial).
'California Wonde r’ peppers were trans
planted on 11 June onto raised beds and level
ground with the plot configuration already
described. Perforated, triple-chambered gar
den sprinkler hoses, 7 m in length, were used
to provide irrigation in sprinkler-irrigated
plots. Raised beds and black polyethylene
mulch were added as variables. The exper
iment was arranged as a split-plot with four
replications. Raised beds and level ground
were two main plot treatments. The six sub
plot treatments were combinations of irri
gation regime and mulch. Trickle-irrigated
plots were watered at - 0 . 0 2 5 and -0 .0 7 5
MPa. Sprinkler-irrigated plots were watered
only at -0 .0 7 5 MPa. A sprinkler treatment
at a minimum soil matric potential of -0.0 2 5
MPa was not included because it was not
considered a feasible practice for commer
cial pepper production. All trickle-irrigated
plots were mulched whereas mulch w as a
variable in sprinkler-irrigated plots.
Measurements of plant height and diam
eter of leaf canopy spread on 10 plants per
plot were taken at three biweekly intervals
beginning 18 July, and ending 15 Aug. The
number of buds on 10 plants per plot that
had reached anthesis by 24 July were counted
as an indication of the potential for early fruit
development and subsequent early yield.
Cumulative yield as well as the percentage
of unm arketable fruit exhibiting solar injury
or blossom-end rot from 40 plants per plot
were recorded throughout the season.
Statistic al an alysis was perfo rm ed by
analysis of variance to segregate the effects
Table 2. Effects of type and frequency of irrigation and mulch on the combined incidence of blo ssom -
end rot and solar injury of ‘Calwon der’ pepper.
Irrigation Mulch
Percent of
total yield
Trickle 15 x Yes 8.3
Trickle 5 x Yes 7.1
Sprinkler Yes 8.8
Sprinkler No 5.4
No irrigation Yes 10.4
No irrigation No 24.8
Significance
Trickle 15 x /mulc h < trickle 5 x /mulch NS
Trickle 5 x/m ul ch < sprinkler/m ulch NS
Sprinkler/m ulch < sp rinkler/no mulch NS
Sprinkler/m ulch < no irrigation/no mulch NS
Sprinkler/no mulch < no irrigation/no mulch * *
No irrigation/mulch < no irrigation /no mulch * *
Sprinkler x mulch **
30 40 50 60 70 80
Days after Transplant ing
Fig. 1. Fluctuation of soil matric potential as influenced by irrigation and mulch (A). Leaf canopy
spread (B) and plant height (C) of ‘Calwonder’ pepper as influenced by mulch and irrigation type
and frequency. Trickle 15 x /mulch (□); trickle 5 x /mulch (♦ ); sprinkler irrigation/mulch (©); sprin
kler irrigation/no mulch ( 0); unirrigated/mulch (■); unirrigated/no mulch (□).
of the main and subplot treatments. Specific
planned contrasts were then performed to es
tab lish si gn ific ant treatmen t differenc es .
Subplot treatm ents that were sprinkler-irri
gated or unir rigated, both mulched and non-
mulched, constituted a 2 x 2 factorial,
examin ing the effects of sprinkler irrigation
(irrigated at - 0.0 7 5 MPa) and black poly
ethylene mulch. The presence of an inter
action of sprinkler irrigation and mulch was
determined and the simple effects of sprin
kler irrigation and mulch were examined by
contrasts of the means. When no interaction
was present, the main effects of sprinkler
irrigation and mulch were examined.
Split plot analysis o f variance of every
measured characteristic revealed no signifi
cant differences resulting from the main plot
treatments of raised beds and level ground.
Therefore, main plot effects were pooled for
the determination o f the subplot treatment
effects.
Soil moisture levels in all but the unirri
gated, nonmulched treatment were similar up
to 9 weeks after transplanting (Fig. 1). The
total precipitation from April through Sep
tember was 578 mm. From the 5th week
after transp lanting, the unirrigated, non
mulched plots had decreasing soil moisture
with a minimum level of - 0 .5 4 MPa. The
unirrigated mulched treatment did not ex
hibit a drop in soil moisture until 9 weeks
after transplanting, reaching a minimum of
-0 . 3 5 MPa.
Plant height and leaf canopy spread in
creased over the season regardle ss of treat
ment (Fig. 1). Plant height and leaf canopy
spread w ere similar for plants in the two tric
kle-irrigated treatments at all times of me a
surement. The comparison of trickle irrigation
with sprinkler irrigation also showed no sig
nificant differences in plant height or leaf
canopy spread. However, in sprinkler irri
gated plots, plant height and leaf canopy
spread showed significant (p < 0.05) pos
itive responses to mulch at all times o f mea
surement. In mulched plots, plant height and
leaf canopy spread did not show a significant
response to sprinkler irrigation. Leaf spread
and plant height at 37 days were similar in
sprink ler-irrigated and n on -irrigated plots
without mulch. However, at 65 days, there
was a highly significant (p < 0.0 1 ) advan
tage to sprinkling. In the absence of irriga
tion, highly significant (p < 0.01 ) responses
to mulch were observed for plant height and
leaf canopy spread at all times of measure
ment. These results indicate a much larger
growth response to mulch than to irrigation.
Earliness of flowering, as indicated by the
number of flowers per plant that had reached
anthesis by 24 July (Table 1), was not en
hanced by the type of frequency of irriga
tion. The plants in the frequent trickle regime
had been irrigated five times by the 24 July
measurem ents, while those in the other ir
rigated regimes had been irrigated once.
Flowering, however, w as more advanced on
mulched than on nonmulched plants.
Early fruit yield (Table 1) reflected the
measurements of early flowering. All mulched
plants had comparable yields regardless of
any irrigation variable. Neither frequency nor
type o f irrigation influenced yields. How
ever, early yield was higher in irrigated than
in nonirrigated plots that were not mulched.
Total fruit yield was similar for high (15
times) and low (5 times) frequency trickle
irrigation (Table 1). Total fruit yield was also
similar under trickle and sprinkler manage
ment. The combination o f any type of irri
gation and mulch produced maximum yields.
Irrigation of bare ground resulted in a 10%
reduction of yield relative to mulched ground.
Plots that were mulched but not irrigated
yielded 10 % less than those that were mulched
and irrigated. Plots that were neither irri
gated nor mulched yielded about 40% less
than those that were irrigated and mulched.
Fruit were smallest and, therefore poten
tially least marketable, in the nonirrigated,
nonmulc hed treatment (Table 1). There was
a statistically significant, but practically un
important difference in fruit w eight between
high and low frequency trickle irrigation.
Blossom-end rot was a common disorder
during the early harvests, while solar injury
predominated during the later harvests. Most
striking was the high percentage of unmar
ketable fruit harvested from the nonirrigated,
nonmulched treatment (Table 2). The wide
fluctuations in soil moisture observed in the
nonir rigated, nonmulched treatment (Fig. 1)
probably contributed to the high incidence
of blossom-end rot, while the exposure of
fruit to direct sun, which resulted from re
duced plant leaf cover (Fig. 2), probably
contributed to the high incidence of solar in
jury late in the season. Irrigation, mulch, or
the combination o f the two markedly re
duced both blossom-end rot and solar injury
relative to lack of irrigation and mulch (Ta
ble 2).
Tr ickle or sprin kl er irrigation w orke d
equally well when application of water was
based upon soil matric potential. However,
in 1985, a moderately dry year, sprinkler
irrigation, which saturated the soil over a
wider area, maintained adequate soil mois
ture longer than trickle irrigation, and, there
fore, required one less irrigation. It may be
that the increased yields often reported to be
due to trickle irrigation in humid areas are
due to the cultural practices often accom
panying the use of trickle, such as mulch and
timely fertilizer and pesticide applications
through the trickle system (9).
In this study, mulch without irrigation re
sulted in slightly higher yield than irrigation
without mulch. Similar results have been ob
served with eggplant (9) and strawberry (11).
Through the combination of irrigation and
mulch maximized total fruit yield, the mar
ginal gain was so small that only one or the
other is likely to be economically advan ta
geous.
Early flowering and early yield were in
creased by the use of mulch in both irrigated
and unirrigated plots, just as in other vege
table crops (4, 6). Improved growth associ
ated with mulched crops resulted from both
the warming effect of mulch and the im
proved soil moisture retention by mulch (5).
The pattern of soil moisture depletion (Fig.
1) suggests that in humid vegetable growing
areas, maximum yields still may be obtained
when irrigation is withheld in mulched pep
pers until quite late, even in a relatively dry
season.
Liter ature Cited
1. Bar-Yosef, B. and B. Sagiv . 1982. Re
sponse of tomatoes to N and water applied
via a trickle irrigation system . Agron. J.
74:637-639.
2. B ernste in , L. and L .E . Fr an co is. 1 983 .
Comp arisons of drip, furrow, and sprinkler
irrigation. Soil Sci. 115:73—86.
3. Bruc e, R.R ., J.L . Chesness, T.C. Keisling,
J.E . P allas, Jr. , D.A. Smittle, J.R. Stansell,
and A .W. Tho mas. 1980. Irrigation of crops
in the southeaste rn United States. Principles
and practices. U SDA Sci. and Educ. Ad
min. Agr. Rev. and Manuals, Southern Se
ries 9.
4. Burg a-Mendoza, C .A. and B.L. Pollack.
1973. A com paris on of degradable and non-
degradable film m ulches for production o f
vegetable crops. Proc. Natl. Agr. Plastics
Conf. 11 :14 9-1 53.
5. Hill, D.E ., L. Hankin, and G.R. Stephens.
1982. Mulches: Their effect on fruit set,
timing and yields of vegetable s. Conn. Agr.
Expt. Sta. Bui. 805.
6. Kohm , P.C. 198 3. The effect of plastic
mulch es and tunnels on yield of bell peppers
(Capsicum annuum L): A study of micro
climate modifica tion. MS Thes is, Cornell
Uni v., Ith aca, N.Y.
7. Liss, H. and B.L . Pollack. 1975. A com
parison o f trickle and sprinkle irrigation of
peppers on polyethylene mulch at different
soil moisture regimes. Proc. Natl. A gr. Plas
tics Conf. 12:27-3 5.
8. Millar, A.A . and W.R . Gardner. 1972. E f
fect of the soil and plant water potentials on
the dry matter production of the snap beans.
Agron . J. 64:55 9-5 62 .
9. Paterson, J.W . and N .J. Smith. 1973. Ni
trogen, mulch and trickle irrigation effects
on eggplant produ ction . Proc. Natl. Agr.
Plastics Conf. 1 1:1 79 -18 6.
10. Phene, C.J. and O.W. Beale. 1976. High-
frequ ency irrigation for water nutrient man
agement in humid regio ns. Soil Sci. S oc.
Amer. J. 40: 43 0-4 36 .
11. Renquist, A.R. , P.J. Breen, and L.W . Mar
tin. 1982. Ve getative g rowths response of
‘Olympus’ strawberry to polyethylene mulch
and drip irrigation regimes. J. Amer. Soc.
Hort. Sci. 1 07 :369-372.
12. S amm is, T.W. 1980. Compariso n of sprin
kler, trick le, subsurface, and furrow irriga
tio n m etho ds fo r row cro ps. A gro n. J.
72:701-704.
HortSci en c e 23(6):988-991. 1988.
Within-row Spacing Effects on Yields
of Celeiy for Processing and Fresh
Market
Peter J, Stoffella1
Agricultural Research and Education Center, IFAS, University of
Florida, P. O. Box 248, Fort Pierce, FL 34954
Herbert H. Bryan2
Tropical Research and Education Center, IFAS, University o f Florida,
18905 S.W. 280 Street, Homestead, FL 33031
Kenneth D. Shuler3
Palm Beach County Extension Service, IFAS, University of Florida, 400
Gulf stream Blvd., Delray Beach, FL 33444
Additio nal index words. Apium grave ole ns, plant density, plant population
Abstract. Celery (Apium graveolens L.) cultivars, Camlyn, Tall Utah 52-70R (IMP.),
Florida 2-14, and Clean Cut were grown at within-row spacings of 10, 20, or 30 cm
during the winter seasons of 1984-85 and 1985-86 in commercial celery fields located
near South Bay, Fla. Stalks were trimmed to 36 or 51 cm height to simulate fresh and
processing celery yields, respectively. Cultivars responded similarly to within-row spac
ings for each measured variable. Untrimmed or trimmed to 51-cm-stalk weights per
plant or per hectare were not different among cultivars. ‘Camlyn’ when trimmed to a
36 cm height had a lower stalk weight and a smaller stalk diameter than the other
cultivars except when compared with ‘Clean Cut’ in the 1984-85 experiment. Un
trimmed and trimmed stalk weights increased linearly per hectare and decreased lin
early per plant as within-row spacings decreased from 30 to 10 cm. Stalk diameter
decreased quadratically as within-row spacings decreased from 30 to 10 cm. Market
able petiole number per plant decreased linearly in the 1984-85 experiment and quad
ratically in the 1985-86 experiment as within-row spacings decreased. Celery stalks
produced at 10-cm within-row spacing were too small for optimum economic fresh
market returns, although they produced the highest marketable yield per hectare for
a processing market. Plants from a 20-cm within-row spacing were optimum for fresh
market celery.
Celery is a major crop in Florida with pro
duction having encompassed about 3400 ha
at a v alu e o f $ 42 .8 m illio n dur in g the 1 98 6-
Received for pu blication 7 Dec. 1987. Florida Ag
ricultural Experimen t Station Journal Series no.
8584. The cost of publishin g this paper was de
frayed in part by the payment o f page charge s.
Under postal regulatio ns, this paper therefore must
be hereby m arked advertisement solely to indicate
this fact.
As so cia te Professor of Ve getable Crops.
2Professor of Vegetable Crops.
3Multi-County Extension Agent.
87 season (2). Plant spacings of 61 cm be
tween rows and 17 cm within rows (4) are
re co mm en d ed to obt ai n o ptim um fres h m ar
ket yields on muck soils of Florida. In a 2-
year study, a reduction in between-row spac
ing from 71 to 61 cm resulted in an increase
in fresh market celery yields (1). As within-
row spacing increased from 15 to 20 cm,
fresh market celery yield per hectare de
creased in one year and no significant effects
on yields was noted in another year (1). In
another study (3) fresh market celery yield s
increased as within-row spacing decreased
from 81 to 61 cm. A prelim inary study re-
