JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND

135

Maataloustieteellinen A ikakauskirja
Vol. 60: 135—152, 1988

Effects of different fertilization practices on the growth,
yield and dry matter content of carrot

AINO-MAIJA EVERS
Kemira Oy, Espoo Research Centre, Luoteisrinne 2
SF-02270 Espoo, Finland

Abstract. The effects of different fertilization practices on the carrot root and shoot dry
weights, yield, dry matter contents and root/shoot ratio were studied in field experiments.
Unirrigated and irrigated placement and broadcast fertilization, fertirrigations without basic
fertilization, fertirrigations with basic fertilization, and PK placement with N fertirrigations
were compared. In addition, split application was compared to single application of nutrients.
The soil nutrient levels were studied by soil analysis. The carrot root and shoot samples were
collected three times during the growing period. Cv. Nantes Duke Notabene 370 was grown.

The carrot shoots reached their maximum weightalready by three months, whereas roots
grew slowly duringthe first two months but grew considerably during both the third and fourth
month. The root and shoot dry weights were positively correlated at all sampling dates in both
years (r a o.77***), The big photosynthetizingapparatus caused the production of high root
yield. The placement fertilization of granular NPK fertilizer increased the yield as compared
to broadcast of granular NPK fertilizer (p = 0.009**). The yield was also increased by the
placement of P and K as compared to treatments without placement fertilization of P and K
(p = 0.03*). There was no difference in yields between single application and split applica-
tion. Irrigation decreased the yield in 1985 (p = 0.03*). In 1986 the yield was significantly
higher than in 1985 (p = 0.000***).

At harvest the fertilization did not affect the dry matter content of carrot roots when com-
pared with unfertilized treatments. The difference in dry matter content was greater between
years (p = 0.000***) than between fertilization practices (p = 0.05*). The treatment PK
placement with N fertirrigations yielded carrots with a higher dry matter content than did the
NPK fertirrigation treatments. Besides the fertilization experiment samples from two organically
cultivated fields were collected to obtain data concerning organicallycultivated carrots and soils.

Key words: fertilization practices, carrot, quality, fresh weight, dry weight, yield, dry matter content, root/shoot ratio

Introduction between yielding and non-yielding parts of the
plant (Hole et al. 1983). In carrots (Daucus

Crop yield depends on total production of
biomass and the distribution of dry matter

carota L.), the leaves constitute the source of
photosynthate production, and the roots form

https://www.c-info.fi/en/info/?token=SPJz2O0DbHoM4CI_.Zt0X18EeOK-eMcI2ztcx3A.H1H-r3zGYIOlqpS-SpiCaaZtdwgJ0iPqFXCn1QojnVG1CBCX8dNo7g-wUx6fy1W2wg2333GGl0maE-OPAoGy7sbq3uiiVtb9aVZONros6ys_ufnlwQGC0HKDPK3yfYiAUuI-UOZvWbRyjijFLNd_CKbE79pBBxEgAgbHH_pb


the main sink where photosynthates are used
and stored.

Scant research data are available about
whether high root yield is correlated with big
foliage or about the optimal root/shoot ratio
during different growing periods in carrot pro-
duction. From the economic point of view, it
is important to have a high root yield at har-
vest, and it can be assumed that big photo-
synthetizing apparatus during the growing
period leads to high production of photo-
synthates for the sink. Dragland (1978) re-
ported that the fertilizer level which gave the
highest root yield had also thebiggest foliage
at harvest. He did not measure the root/shoot
ratio during the growing season. Tanaka
(1980) reported that the timing of nitrogen
application to rice has the effect of manipu-
lating the source-sink relationship.

Broadcast fertilization is the most com-
mon fertilization practice in carrot produc-
tion in Finland. The split application is not
used. The nutrient amounts used are 80—

140 kg N/ha, 30—70 kg P/ha and 60—200 kg
K/ha. In corn production in Finland, place-
ment fertilization has given very good results
(Aura 1967, Kaila & Elonen 1970, Esala &

Larpes 1986 a, b).
The aim of the present study was to deter-

mine whether the root and shoot dry weights,
yield, dry matter contents and the root/shoot
ratio can be affected by developing the meth-
ods of fertilizer application. Placement fer-
tilization, broadcast fertilization, fertirriga-
tion, and theircombinations were compared.
The split application was also compared to
single application of nutrients.

Materials and methods

The field experiments were carried out on
theKotkaniemi Experimental Farm of Kemi-
ra Ltd. in Vihti (60°22'N, 24°22'E) during
the growing seasons of 1985 and 1986. The tri-
als were set up according to the method of
completely randomized blocks, four blocks

Table 1. The fertilization treatments.

Treatment Code Number and time of Macro nutrient Irrigation water
fertilizer applications amounts in 19863 amounts in

kg/ha 1985 and 1986
mm

N P K

No fertilization
No irrigation PO 0 0 0 0 0
Irrigation PI 0 .0 0 0 3xlo

NPK placement
No irrigation P 2 1 before sowing 80 35 133 0
Irrigation P 3 1 before sowing 80 35 133 3x 10

NPK broadcast
No irrigation P 4 1 before sowing 80 35 133 0
Irrigation P 5 1before sowing 80 35 133 3x 10

NPK fertirrigation
No basic P 6 3 during season 80 29 160 3x 10
1/2 NPK basic 1 P 7 1 before sowing and 80 32 142 3x 10

3 during season

PK placement2
3N-fertirrigation P 8 1 before sowing and 81 56 133 3x 10

3 during season
4N-fertirrigation P 9 1 before sowing and 155 56 133 3x 10

4 during season

1 Half of the nutrients were given in basic placement fertilization and half in NPK fertirrigations.
2 Phosphorus and potassium were given in basic placement fertilization and nitrogen in fertirrigations.
3 The nutrient amounts were 33 % higher in 1985 than in 1986.

136



(I —IV), ten treatments (PO —P9, Table 1)
and plots of 25 m 2 (55 row meters in each).
The data were studied by contrast analysis
(PO —P9) and by analysis of variance as a fac-
torial experiment (PO —P 5), where the fer-
tilization levels were 1) no fertilization, 2)
placement fertilization, 3) broadcast fertiliza-
tion. The irrigation levels were 1) no irriga-
tion, 2) irrigation (Steel & Torrie 1980).

Simultaneously with the fertilization ex-
periment, samples from two organically cul-
tivated fields were collected in 1986. These
were grown with the same seed material, but
the geographical position, climate and soil
characteristics were different. The aim of this
sampling was to obtain some data concerning
organically cultivated carrots and soils.

Fertilization
In placement fertilization treatments (Ta-

ble 1) the granular NPK fertilizer (10-4-17 with
microelements) was placed 8 cm deep in the
soil, and the fertilizer rows were marked.
The seeds were sown with a MiniNibex sowing
machine 1 cm deep and 3 cm beside the fer-
tilizer row. In broadcast treatments, the gran-
ular NPK-fertilizer (10-4-17 with micronu-
trients) was spread on the soil surface and
harrowed with a rotary cultivator. In the

NPK fertirrigation treatments the water-
soluble NPK fertilizer (10-3.6-20) was dis-
solved in water and spread with a self-made
boom. The same boom was used in irrigation.
In NPK-fertirrigation treatment with basic
fertilization, half of the nutrients was applied
with granular NPK fertilizer (10-4-17 with
microelements) by the placement method, and
half of nutrients with soluble NPK fertil-
izer (10-3.6-20) in three applications. In N-
fertirrigation treatments, the basic PK-fer-
tilization was done with granular PK-fertilizer
(0-7-17 with microelements) by placement
method. The nitrogen fertilizer (1985 calcium
nitrate, 1986 urea) was dissolved in water
and spread with the boom three or four times
during the growing season. All fertilizer per-
centages are expressed as pure elements.

The basic fertilization was done on 4th
June, 1985 and 6th June, 1986. The fertirriga-
tions and irrigations were done on 14th June,
sth July and 19th July, 1985 and on 26th
June, 10th July and 24th July, 1986.

In 1986 the amounts of nutrients in the
treatments were 33 % less than in 1985 (Table
1). All fertilized treatments contained the
same amounts of micronutrients, 1.2kg B/ha,
0.8 kg Fe/ha, 0.8 kg Cu/ha, 0.8 kg Zn/ha,
5.6 kg Mn/ha, 0.08 kg Mo/ha and 0.013 kg
Se/ha. The treatment NPK-fertirrigation

Table 2. The nutrient contents of composts used at the organically cultivated locations as well as the amounts of
nutrients given in compost fertilization.

The nutrient contents The amount of nutrients
of composts given in fertilization

% in dry matter kg/ha

Location 1 Location 2 Location 1 Location 2

Water-soluble N 0.18 0.07 113 47
Total N 0.73 0.63 450 424
Total P 0.45 0.39 275 262
K 0.53 0.44 325 296
Mg 0.41 0.41 250 276
S 0.13 0.12 77 81
B 0.002 0.002 1.5 1.3
Fe 1.01 1.05 619 706
Cu 0.002 0.002 1.0 1.3
Zn 0.008 0.01 4.8 6.7
Mn 0.03 0.02 18.4 13.5
Mo 0.00009 0.0001 0.055 0.067

137



Table 3. Weather conditions at Vihti in 1985 and 1986 and the 30-year average.

Mean day temperature Precipitation • Sunshine hours
°C mm h

1985 1986 1931—60 1985 1986 1931—60 1985 1986 1959—84

May 9.0 10.8 9.0 40 51 39 263 267 268
June 13.2 16.3 14.2 52 28 46 250 326 282
July 15.4 16.3 16.8 72 103 73 236 281 254
August 15.8 13.2 14.9 79 138 77 199 154 212
September 8.7 6.4 9.9 75 88 66 145 135 127
October 6.8 5.5 4.7 29 74 65 108 87 71
Total 347 482 366 1,201 1,250 1,214
* Helsinki-Vantaa airport

without basic contained no Fe at all, whereas
the treatment NPK-fertirrigation with 1/2
basic contained 0.4 kg Fe/ha. During winter
1985 the experimental field was limed with
dolomite lime, 5,000 kg/ha.

The biologically cultivated fields were fertil-
ized with compost, 1,250 kg/100 m 2 (Table 2).

Growing technique and climate

The carrots were grown according to the
normal growing practise used in Finland.
Seeds of cv. Nantes Duke Notabene 370 were
coated with a mixture of lindan (75 °7o) and
tiram (10 %), using 120 g pesticide/kg seeds.
The seeds were sown on Bth June, 1985 and
9th June, 1986. The organically cultivated
carrots were sown on 14thMay, 1986 at loca-
tion one and 21st May, 1986 at location two.
The plants were thinned for 30 plants/m.
Weeds were sprayed with promethryn twice
per year. Sypermetrin was used for protection
against Trioza apicalis F. The informationon
climate is given in Table 3.

Carrot samples

The total growing time was four months.
The first sampling date was 2.5 months after
sowing in 1985, 2 months in 1986. The second
sampling date was 3 months after sowing. The
third sampling date was at harvest, four
months after sowing. Each time, 20 consecu-
tive plants per plot were collected from the

middle of the plantation. For dry weight the
shoots and roots were dried at 60°C for 48
hours. The dry matter content is expressed as
the percentage of dry weight in fresh weight.

Soil samples
Soil samples were collected across the carrot

row from a soil layer 15 cm deep. In all, eight
partial samples per plot were gathered at equal
distances across the plot. Soil samples were
taken two days before sowing and 6, 27, 41,
54, 76, 96 and 116 days after sowing in 1985.
In 1986 the soil samples were taken one day
before sowing and 18, 31,46, 65 and 117 day
after sowing.

Soil samples were analysed in a commercial
laboratory, Viljavuuspalvelu Oy, located in
Helsinki. N03-N was extracted with water
( + 20°C) and determined by the ionspecific
electrode method (modification of Bremner
et al. 1968). NH 4-N was extracted with 0,1
M K :S0 4 and determined by the Kjeldahl
procedure. P, K, Ca and Mg were extracted
with ammonium acetate, pH 4.65. P was
determined by spectrophotometry, using am-
moniummolybdate as the colour reagent; Mg
was determined by AAS (Atomic absorption
spectrophotometer), K and Ca by a flame
photometer (Vuorinen & Mäkitie 1955). B
was extracted with boiling water (+ 100°C)
and determined by an ICP-spectrometer
(Berger & Truog 1944). S was extracted with
0.01 M CaCl2 and determined gravimetrically
with barium sulphate (Salonen et al. 1965).

138



Table 4, Chemical characteristics of experimental blocks (1985), treatments (1986) and biologically cultivated fields
(1986) in the spring before fertilization.

1985 pH jl NOrN NH4-N P K Ca Mg S B Fe* Mn* Cu* Zn* Mo*

I 5.6 0.6 <lO 3.9 7 115 1675 240 12.4 0.7 11.0 7.9 7.8 29.3 0.51
II 5.7 0.3 <lO 0.1 11 95 1000 75 7.0 0.5 4.7 9.4 4.4 14.7 0.53
111 5.8 0.5 <lO 2.5 9 110 1625 140 4.6 0.7 9.0 6.8 8.6 25.0 0.64
IV 5.7 0.6 <lO 0.1 10 95 1050 65 8.5 0.6 3.1 8.8 7.0 13.7 0.68

1986

P0 1 6.2 1.0 1.0 1.3 10.6 110 2356 135 4.4 0.6 450 12.2 3.9 3.6 0.09
PI 6.4 1.3 0.9 0.2 9.4 110 3050 119 7.8 0.6 430 8.8 3.9 6.6 0.07
P 2 6.3 0.9 0.9 0.4 10.6 143 2475 144 9.9 0.8 520 11.8 4.0 3.3 0.09
P 3 6.2 0.8 0.6 0.4 11.3 135 2194 108 8.9 0.8 440 12.0 4.0 3.6 0.09
P 4 6.3 0.9 1.4 2.1 11,3 115 2625 119 4.8 0.6 410 11.0 4.3 4.6 0.09
P 5 6.3 1.0 2.4 2.1 10.8 123 2794 155 3.3 0.7 480 9.2 4.1 4.1 0.08
P 6 6.2 0.9 0.8 1.6 11.7 138 2613 154 11.0 0.8 480 12.8 4.8 4.0 0.12
P 7 6.4 0.9 0.8 2.6 10,6 126 3175 151 7.7 0.7 600 12.0 4.8 3.6 0.12
P 8 6.4 0.9 0.9 4.6 14.8 140 2513 113 12.0 0.8 420 11.5 4.1 5.1 0.11
P 9 6.3 1.0 0.9 7.8 12.1 136 2575 109 7.7 0.8 410 11.9 4.2 3.8 0.12
LI 2 6.2 0.4 11 2.7 20 88 725 80 3.2 0.3 210 39 2.8 9.2 0.13
L 2 7.2 0.9 12 4.6 126 218 2475 296 1.9 0.7 360 19 5.6 23.0 0.08
• Different determinations in 1985 and 1986.

1 See treatments in Table 1.
2 Organically cultivated fields.

In 1985, Fe, Cu, Zn, Mn and Mo were ex-
tracted with ammonium acetate (pH 4.65).
In 1986 these elements were extracted with
ammonium acetate-EDTA (pH 4.65, 0.02 M
EOTA). Fe, Cu, Zn and Mn were determined
by flame AAS and Mo by flameless AAS
(Takanen & Erviö 1971).

The first sampling was done before the fer-
tilization application on 4th June 1985 by
blocks and 6th June 1986 by treatments, be-
cause the same plots were used each year
(Table 4). Table 4 also presents the results
for the biologically cultivated fields (loca-
tion 1 at Varkaus and location 2 at Ranta-
salmi). The soil in the fertilizer trial was fine
sand (15 —30 °7o clay), with a humus content
of 12—20 %. The soil in the organically cul-
tivated fields was fine sand moraine, with a
humus content of 3—6 % in one location and
of 12—20 % in the other location.

Results

Growing rhythm

On average, the carrot shoots grew faster
in 1986 that in 1985 (Fig. 1). By the middle

of the growing season, the carrot shoots
reached 40 % of their final shoot fresh weight
in 1985, 68 % in 1986. By the third quarter
of the growing season, the shoots reached
95 °7o and 113 % of their final fresh weight
but only 75 °7o and 95 % of their final dry
weight in 1985 and 1986,respectively. In both
years the final shoot yield was very similar.

Carrot roots developed slowly. By the
middle of the growing season, the root fresh
weight reached only 17 % (1985) and 26 %

(1986) of the final root fresh weight. The
corresponding figures on the second sampling
date were 59 % and 72 °7o. Thus the carrot
root weight increased considerably during the
last month of the growing period. The result
was similar when calculated for dry matter.

In 1985, the mean weights of a single carrot
root were 15.4 g, 53 g and 89 g on the con-
secutive sampling dates. The corresponding
weights in 1986 were 27.2 g, 77 g and 106 g.

Root dry weight

The difference in the dry weights of roots
between treatments increased as the growing

139



140

Fig. I. The development of fresh and dry weights of roots and shoots on three sampling dates in the fertilization
experiment and in the organically cultivated locations.



season proceeded (Fig. 2). There was no
notable difference on the first sampling date,
two months after sowing. Three months after
sowing, on the second sampling date, the
highest dry weight of roots was obtained with
the PK placement with 3N fertirrigations
treatment. The difference between the highest
and the lowest root dry weights in fertilized
treatments was 23.7 g/20 carrots, which
equals a calculated value of 711 kg dry mat-
ter/ha (Fig. 2).

At harvest the best fertilization practices,
according to the dry weight of carrot roots,
were irrigated broadcast, irrigated placement
and PK placement with 3N fertirrigations. The
difference between the fertilization treatment
yielding the highest dry weights of roots and
the fertilization treatment yielding the lowest
dry weights of roots was 42.1 g/20 carrots,
which equals a calculated difference of 1,263
kg dry matter/ha (Fig. 2).

Fig. 2. The effect of different fertilization practices on the development of the dry weights of roots.

141



142

Shoot dry weight tively correlated on all sampling dates and in
the two years as follows:

The shoot dry weight varied already on the
first sampling date (Fig. 3). In fertilized treat-
ments the difference between the highest and
the lowest value was about similar on the first,
second and third sampling dates, being 8.6,
11.7 and 10.4 g/20 carrots, respectively (at
harvest the unirrigated placement fertilized
treatment was omitted).

KAI KA2 KA3

1985 r = o.B6*** r = o.77*** r = o.79***
1986 r = o.77*** r = o.B4*** r = o.Bo***

Yield

On average, all treatments gave a 42 %

higher yield in 1986 than in 1985 (Table 5).The root and shoot dry weights were posi-

Fig. 3. The effect of different fertilization practices on the development of the dry weights of shoots.



Table 5. The effect of different fertilization practices on the carrot yield.

Treatment Yields and standard errors
tons/ha

Average
yield

tons/ha1985 1986

No fertilization
No irrigation 36.413.1

32.013.0
47.611.5
45.815.4

42.0
Irrigation 38.9

NPK placement
No irrigation 37.712.7

38.611.5
50.612.4
56.613.4

44.2
Irrigation 47.6

NPK broadcast
No irrigation 37.112.9

25.912.6
48.211.8
48.214.8

42.7
Irrigation 37.1

NPK fertirrigation
No basic 35.115.9

36.012.1
52.113.7
55.011.6

43.6
1/2 NPK basic 45.5

PK placement
3N fertirrigation 39.812.0

37.711.8
48.4 +6.5
52.612.2

44.1
4N fertirrigation

Average yield

45.2

35.6 ± I 50.5 + 1.1 43.1

Contrast analysis revealed that placement fer-
tilization produced higher yields than broad-
cast fertilization (p = 0.009**). The yields were
higher also when phosphorus and potassium
were applied by placement fertilization com-
pared to the treatments where P and K were
not applied by placement method (p = 0.03*).

The split application did not affect the yield
when compared to single application.

Of the individual fertilization practices, the
best yield was obtained by irrigated placement
fertilization, followed by NPK fertirrigation
with NPK basic fertilization and PK place-
ment with 4N fertirrigations. NPK fertirriga-
tion without basic fertilization gave moderate
yields in each year. Broadcast fertilization
proved to be the poorest method of fertiliza-
tion, the yields being similar to those obtained
with unfertilized treatments.

In a factorial experiment, irrigation de-
creased the yield in 1985. The average yield
for irrigated treatments was 32.2 t/ha; for
non-irrigated treatments it was 37.1 t/ha
(p = 0.03*). In 1986, irrigation increased the
yields. The yield of irrigated treatments aver-
aged 50.2 t/haand of non-irrigated treatments
48.8 t/ha (p = 0.06). Placement fertilization

yielded 38.2 t/ha and broadcast fertilization
31.5 t/ha (p = 0.06) in 1985, in 1986 53.6
t/ha and 48.2 t/ha (p = 0.10), respectively.

Root/shoot ratio

The root/shoot ratio increased and the dif-
ferences between treatments increased with
advancing growing season (Fig. 4).

Dry matter content, shoots

Fertilization did not affect the dry matter
content as compared to unfertilized treat-
ments. On the first, second and third sampling
dates, the mean dry matter contents of shoots
were 12.1 % (range 11.7—12.6 %), 11.4 %

(range 11.0—12.0 %) and 14.0 % (range
13.7—14.4 %), respectively. On the first
sampling date the dry matter content was
higher for broadcast fertilization than for
placement fertilization (p = 0.009**). The
value was also higher when P and K were not
placement fertilized compared to P and K
placement (P = 0.009**). On the second and
third sampling dates there were no statistical
differences between fertilization practices.

143



Dry matter content, roots

The dry matter content was lower in the
roots than in the shoots. On the first sampling
date, the mean root dry matter content was
9.1 % (range 9.0—9.3 %), on the second
sampling date 9.4 % (range 9.1—9.6 %). On
the second sampling date the dry matter con-
tent of roots was higher when basic and addi-
tional fertilization was used as compared to
fertirrigation (p = 0.006**). The dry matter
content was also higher when P and K were

applied by placement fertilization when com-
pared to treatments where P and K were not
placement fertilized (p = 0.02*). At harvest,
the mean dry matter content was 10 % (range
9.8—10.2 %). The dry matter content in roots
was higher with the PK basic with N fertirriga-
tions method than with the NPK fertirriga-
tions treatments (p = 0.03*).

The content was also higher whenbasic and
additional fertilization was used as compared
to fertirrigation (p = 0.05*).

Fig. 4. The effect of different fertilization practices on the development of the root/shoot ratio.

144



There was a highly significant difference
between the two years (p = 0.000***) as
to root dry matter content. The mean values
were 9.5 % and 10.5 % in 1985 and in 1986,
respectively. When treatments PO—PS were
studied as a factorial experiment neither the
fertilization method nor irrigation affected the
dry matter content of carrot roots.

Organically cultivated carrots

The fresh and dry weights of shoots and
roots are shown in Fig. 1. In the two organi-
cally cultivated fields, the yields were 46.2 ±

1.4 and 41.4 + 2.7 t/ha, respectively. The
dry matter content of carrot shoots were
11.3 % and 10.3 % on first sampling date, at
the second sampling date 11.8 % and 9.6 %,

respectively. At harvest, the shoot dry matter
content was not determined. The root dry
matter contents on three sampling dates were
9.4 and 9.1 %, 7.1 and 7.6 % and 10.5 and
9.6 %, the root/shoot ratios on fresh weight
basis were 2.7 and 1.8, 3.3 and 2.7 and 4.8
and 3.4 in the two organically cultivated fields
respectively.

To make it easier to see the differences
between the organically cultivated carrots and
the carrots in the fertilizer experiment (the fer-
tilized treatments), the mean values at harvest
1986 are listed side by side as follows:

Organically Fertilization
cultivated experiment

1986

Shoot fresh weightg/20 carrots 424 667

Shoot dry weight g/20 carrots —* 85.8
Root fresh weight g/20 carrots 1716 2175
Root dry weight g/20 carrots 173.6 227.5
Yield kg/16 row meters 35.0 41.2
Shoot dry matter content % —* 12.9
Root dry matter content % 10.1 10.5
Root/shoot ratio (fresh
weight basis) 4.1 3.3
* Not determined

The yield of organically cultivated carrots
was somewhat smaller than the average yield
for fertilized carrots grown in the fertilization
experiment. There was no appreciable dif-
ference between root dry matter content but

the root/shoot ratio was higher in organical-
ly grown carrots than in those grown in the
fertilization experiment.

Soil analysis
The dissimilar effects of different fertiliza-

tion practices on the soil nutrient concentra-
tions can be verified by soil analysis (Fig. 5).

During germination the highest N0 3-N
concentrations ( ~25 mg/1) were observed nat-
urally in plots where all nutrients were given
in single application before sowing (Fig. 5).
In 1985 the NQ3-N concentrations were 40—

50 mg/1 during the first 50 days, and they
decreased sharply thereafter in all fertilization
treatments, except for placement fertilization,
where the values ranged 50—90 mg/1 during
the first 50 days. In 1986 the highest N0 3-N
concentrations were observed in broadcast fer-
tilization 30 days after sowing. In organically
cultivated fields, the NQ3-N concentration
was 15 mg/1 before sowing, increased to 25—

40 mg/1 during the first 40 days and decreased
thereafter.

In 1985, 20—45 mg/1 of NH 4-N was de-
tected in unfertilized and single-application
treatments. In 1986, in split application treat-
ments as well as in single-application treat-
ments, the NH 4-N concentration was <lO
mg/1. In organically cultivated soils the values
ranged 0—25 mg/1.

The phosphorus concentrations were similar
in all soil samples in the fertilization experi-
ment. In organic cultivation the soils had a
higher P content (Fig. 5).

The potassium content in unfertilized treat-
ments decreased from 110 mg/1 to 50 mg/1
during the growing season (Fig. 5). Fertiliza-
tion increased the K level in soils. In treat-
ments where K was applied by placement fer-
tilization potassium behaved similarily. Dur-
ing the first 40 days, the K values ranged 110—
150 mg/1, then dropped to ~ 100 mg/1, and
were 60—80 mg/1 at harvest. In broadcast fer-
tilization, the K levels were highest during the
first 40 days, being 150—160 mg/1; it de-
creased thereafterand was 70 —80 mg/1 at har-
vest. The potassium content in the fertirriga-

145



Fig. 5. The effect of different fertilization practices on the nutrient levels, pH and electrical conductivity of the soil.

146



tion treatment ranged 100—160 mg/1. The K
contents in organically cultivated fields were
90 mg/1 and 200 mg/1 seven days after sowing,
increased thereafter at both locations, reached
their maximum values 150 mg/1 and 360 mg/1
40 days after sowing and finally decreased to
the original values.

The calcium and magnesium values are not
shown in Fig. 5 because they were very similar
in all treatments. The Ca concentrations
ranged from 800 to 1,600 mg/1 in 1985 and
from 1,900 to 3,000 in 1986 as a result of
liming. In one of the organically cultivated
fields, the Ca concentration was 800—1,100
mg/1 and in the other 2,500—3,000 mg/1.
The magnesium concentrations ranged SO-
HO mg/1 in the fertilization experiment, and
in organically cultivated soils the Mg values
were 100—170 mg/1 and 290—360 mg/1.

The pH was different in 1985 and in 1986
because of liming during the winter 1985/
1986. The pH tended first to fall and then to

rise during the growing season (Fig. 5).
The electrical conductivity (EC) during the

first 30 days when carrots germinate and
emerge was higher in single-application treat-
ments than in split application treatments.
In 1985 the treatments where P and K were
applied by placement fertilization, the EC
was higher than in other treatments. In 1986
the broadcast fertilization treatments had
especially high EC, 20 days after sowing. The
ECs of organically cultivated soils were of the
same magnitude as in soils of the fertilization
experiment.

Discussion

Carrot is one of the most important vege-
tables grown and stored in Finland. The
growth of carrot is influenced by genotype,
environment and growing techniques. In the
present study, cv. Nantes Duke Notabene
370 was used. This variety is most common-
ly grown for the food industry in Finland.

The root and shoot dry weights were posi-
tively correlated on all sampling dates of both
years (r o.77***); big foliage produced

high root yield. A similar result has been re-
ported by Dragland (1978). Carrot shoots
reached their maximum weight by three
months whereas the roots grew slowly during
the first two months, but growth increased
considerably during the third and fourth
months. Big photosynthetizing apparatus
seemed provide plenty of photosynthates for
the growing root.

Placement fertilization
The average carrot yield in Southern Fin-

land is 23 tons/ha (range 18—28 tons/ha), and
30—36 tons/ha on contract farms (Ylätalo
1982). The most common fertilization practice
is broadcast fertilization. According to the
present study, development of the fertiliza-
tion practises could increase the carrot yield.
The placement of granular NPK fertilizer in-
creased the yield considerably as compared to
broadcast fertilization of granular NPK fer-
tilizer. The yield was also increased by the
placement of P and K as compared to treat-
ments where P and K were not applied by
placement method.

Ekeberg (1986) also studied the effects
of placement and broadcast fertilization on
carrot, and found that placement fertiliza-
tion increased carrot yield by 2 % and 12 %

in the dry years of 1981 and 1982, respectively,
but it did not affect the yield in the rainy
year of 1980. In broadcast fertilization, the
fertilizer granules remain in the top o—s0—5 cm
of the soil (Kaila & Hänninen 1961), which
dries quickly, and the granules thus do not
dissolve in dry periods. In placement fer-
tilization, the fertilizer granules are placed
under the soil surface at a depth of B—ls8 —15 cm,
where moisture conditions remain optimal
for granules to dissolve. In rainy years the
granules dissolve also in the top soil layer. This
may explain why Ekeberg (1986) did not get
differences between placement and broadcast
fertilization in the rainy year of 1980.

Esala & Larpes (1986 a) have reported
placement fertilization to increase barley and
spring wheat yields, particularly at low fer-

147



148

tilizer levels. The placement application in-
creases the effiency of the fertilizer. In the
present study, the difference in carrot yields
between placement and broadcast practices
would probably have been even bigger if a
lower nutrient level had been used. The nu-
trient level used in the present experiment was
chosen according to the practice in Finnish
carrot production. It would be worth while
to study the lowest effective fertilizer levels
of placement method that would achieve
yields similar to those of the inefficient broad-
cast method. From the ecological point of
view, too, this would be an interesting topic.
Nitrogen in particular is a nutrient which is
easily leached by rain or irrigation (Watts
1975).

Fertirrigation
Hergert (1977) reported that although all

nutrients may be applied in the irrigation
water, there are some limitations as to those
that probably should not be applied, because
of effectiveness. He claims that the nutrients
which are not absorbed by the soil and which
have a tendency to move with soil water are
the ones best suited for sprinkler application.
Thereby nitrogen, sulfur, and probably some
of the chelated micronutrients are suited for
application in irrigation water.

Nutrients such as Mg, Ca, K, P and in-
organic forms of micronutrient cations may be
soluble in the irrigation water. Because of soil
reactions, however, they tend to accumulate
in the top inch or two of the soil surface.
These nutrients would not be distributed
throughout the root zone to be taken up by
the roots of the growing crop (Hergert
1977). On the contrary, storage organ of the
carrot is formed of a tap root and hypocotyl,
with lateral roots arising in both of them
(Esau 1940). This means that carrots have
lateral roots along the soil profile, which can
probably take up nutrients also from the top
layer if the soil moisture content is optimal.
But because the top layer is often dry, this may
hinder the nutrient uptake of fertirrigated
nutrients as well as broadcast nutrients.

Work by Watts (1975) with sprinkler ap-
plication of nitrogen solutions on sandy soils
has shown greater efficiency of use from
sprinkler-applied nitrogen than preplant broad-
cast nitrogen. In that study, the nitrogen losses
increased as the nitrogen rate increased re-
gardless of the application method. Much of
the loss was due to leaching. Losses from the
sprinkler-applied nitrogen (split) were lower
than from the broadcast-applied nitrogen.

In the present study, no difference could be
shown in yields between one application and
split application. Future studies should in-
vestigate the effects with a lower fertilization
level.

Weather conditions

There was wide variation in yields between
the years. In 1986, the yields were significantly
higher (p = 0.000***) than in 1985. Bishop

et al. (1973) has reported a wide range in
carrot yields for different years at the same
location as well as for different locations in
the same year. Vuorinen & Takala (1987)
have reported 64 % lower yields between 1980
and 1982 and, on average, 60 kg N/ha gave
the highest yield, but in 1980, 120 kg N/ha
gave the biggest yield. Also Nilsson (1979)
has reported differences (25 %) in yields be-
tween years, whereas the amount of fertilizer
was found to have no effect on carrot yields.
In the present study the amounts of fertilizer
used were higher in 1985 than in 1986. At least
the higher N amount in 1985 did not affect
on the yield levels, because the treatment
PK placement with 4N fertirrigations had
very high nitrogen amounts in both years
(155 kg N/ha in 1985 and 200 kg N/ha in
1986), and in both years this treatment gave
equally good yields as did the PK placement
with 3N fertirrigations. The surplus nitrogen
did not lower the yield in either year.

Irrigation

Irrigation decreased the yields in 1985 and
increased them in 1986, although the total



149

precipitation was greater in 1986 than in 1985.
The high precipitation rate in June, 1985
should be noted. In that year heavy rains came
two days after the first irrigation, at the time
when seedlings began to emerge. The heavy
rain caused a crust to form on the soil surface,
and the crust hindered the emergence of
seedlings and prevented gas exchange in the
soil. The soil was fine sand which contained
15—30 % clay, enough to form a crust. In
both years the sowing could take place only
very late. In 1985 the first irrigation and fer-
tirrigation was done too early with respect to
the sowing date. It would have been better to
give the first fertirrigation only after plant
growth had made a good start. Also the num-
ber of sunshine hours in June and July, 1985
was lower than in 1986, and retarded early
development. In 1986, the first irrigation and
fertirrigation was done not until at the end
of June, which was favourable. Dragland

(1978) has reported that an early drought
period from the two true leaf stage onwards
resulted in higher carrot root yield.

Dry matter content

In the present study, the mean dry matter
content in roots was 10 % at harvest. The
difference in the dry matter content of roots
was bigger between years than between fer-
tilization practices. Similar results have also
been reported by other researchers (Drag-
land 1978, Aura 1985, Vuorinen & Takala
1987). These researchers found that increasing
amounts of N did not affect the dry matter
content in carrot roots. Aura (1985) and
Vuorinen & Takala (1987) also found that
irrigation did not affect the dry matter con-
tent, but Dragland (1978) reported that a
drought period before harvesting increased the
dry matter content. In Nilsson’s (1979) study
there was no difference between the dry mat-
ter content of carrot roots with normal or half
the normal NPK fertilizer levels. Ekeberg

(1986) reported that placement fertilization
decreased the dry matter content in carrot
roots as compared to broadcast fertilization

on peaty soil. Nor did an increased N amount
decrease the dry matter content. In the present
study, no difference was found between place-
ment and broadcast fertilization, but the PK
placement with 3N fertirrigations had a higher
dry matter content than the NPK fertirriga-
tions treatments.

In the present study the dry matter con-
tent was, on average, somewhat lower than
in the other experiments. The ranges were as
follows: 9.0—10.2 % (present study); 9.2
13.5 % (Dragland 1978); 11.4—12.0 %

(Nilsson 1979); 11.0—12.6 % (Aura 1985);
10.6—11.2 % (Ekeberg 1986); and 9.8
12.4 % (Vuorinen & Takala 1987). The
reason for the slightly lower mean dry matter
content may be climatic or genetic. In both
years September was rainy, and according to
Dragland (1978), a dry period before har-
vest increases the dry matter content in carrot
roots. Bajaj et al. (1980) studied various
chemical constituents of 23 carrot varieties
grown in the same conditions. They found a
42 % difference in the dry matter content of
carrot varieties (range 7.9—11.2 %). Drag-

land (1978) and Ekeberg (1986) grew cv. Tip
Top Red Core. Nilsson (1979) and Aura
(1985) grew cv. Nantes Fancy Notabene, and
Vuorinen & Takala (1987) grew cv. Nantes
Notabene 20.

Root/shoot ratio

The highest root/shoot ratios were found
in fertilization practices which also had high
yields. These were the irrigated placement
fertilization and the PK placement with 4N
fertirrigations. The development of root/
shoot ratios in these treatments was 1.0—

1.8—2.4 and 1.0—1.7—2.3 on the basis of dry
weight on the first, second and third sampling
dates, respectively. The trend was that the
higher the yield, thebigger was the root/shoot
ratio, with two exceptions, which were thePK
placement with 3N fertirrigations and irrigated
broadcast fertilization.

A high yield was obtained by the PK place-
ment with 3N fertirrigations. This treatment



favoured shoot growth. The treatment had the
highest root and shoot dry weights, but the
root/shoot ratio was only 0.9—1.5—2.0,
which means that dry weights of shoots were
particularly high. The irrigated broadcast
treatment had a high root/shoot ratio and a
high root and shoot dry weight, yet the yield
was low in both years. The reason for this in-
consistency remained uncertain.

Organically cultivated carrots
The organically cultivated location one had

low nutrient levels in the soil, with the ex-
cept of P, Mn and Zn. Location 2 had high
nutrient levels in soils, except for S. The
nutrient amounts given by fertilization with
compost were much higher than those in the
fertilization experiment. The most distrikt
difference between composts was the amount
of water-soluble nitrogen. Despite the huge
nutrient amounts, the fresh and dry weights
of 20 carrots (Fig. 1) remained below the
average value for 1986 in the fertilization ex-
periment. The organically cultivated carrots
were sown earlier than those of the fertiliza-
tion experiment, and the root and shoot fresh
and dry weights had already reached high
levels on the first sampling dates. Location
one got 113 kg/ha water-soluble nitrogen,
while location two only 47 kg/ha water-
soluble nitrogen. This is probably the reason
for the lower yield at location two. There was
no difference in the root dry matter content

between the organically cultivated carrots and
the fertilized carrots of the fertilization ex-
periment.

The root/shoot ratio had to be calculated
on the basis of fresh weight, because the
shoot dry matter contents at harvest were not
determined. The root/shoot ratio was higher
for the organically grown carrots than was the
average value for the fertilized carrots in the
fertilization experiment.

According to these experiments, high carrot
yields were obtained when the total biomass
production was high. The big photosynthe-
sizing foliage did produce plenty of photo-
synthates for the roots. It proved to be pos-
sible to increase the carrot yields by developing
the fertilization practices. Placement fertiliza-
tion increased the yields as compared to
broadcast fertilization. The placement of P
and K increased the yields, as compared to
treatments where P and K were not applied
by placement method. The split application
did not affect the yield when compared to one
application. Fertilization did not affect the dry
matter content as compared to unfertilized
treatments.

Acknowledgement. 1 am indebted and grateful to Ms.
Oili Uusitalo for excellent technical assistance. I am
grateful to Professor E. Kaukovirta, Professor A-L. Va-
ris and M. Niemi, Lie. Phil., for their valuable com-
ments on the manuscript. I also thank V-M. Taavitsai-
nen, Lie. Phil., for advice in the statistical analysis and
Mrs. A-M, Korhonen for the typing. I am grateful to the
Academyof Finland and Kemira Oy for financial support.

References

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1985. Avomaan vihannesten veden ja typen tarve. Maa-

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SELOSTUS

Lannoitusmenetelmien vaikutus porkkanan
juurien ja naattien kuivapainoon, satoon,
kuiva-ainepitoisuuteen ja juuri/naatti
-suhteeseen

Aino-Maija Evers
Kemira Oy, Espoon tutkimuskeskus,
Louleisrinne 2, 02270 Espoo

Eri lannoitusmenetelmien vaikutusta porkkanan ’Nan-
tes Duke Notabene 370’ juurien ja naattien kuivapainoon,
satoon, kuiva-ainepitoisuuteen ja juuri/naatti -suhteeseen
tutkittiin kenttäkokeina Kotkaniemen koetilalla Vihdis-
sä 1985 ja 1986.Sijoitus- ja pintalannoitusta(ilman kas-
telua ja kastelun kera), NPK kastelulannoitusta, NPK kas-
telulannoitusta, jossa puolet ravinteista annettiin sijoit-
taen keväällä sekä koejäsentä, jossa P ja K annettiin si-
joittaen keväällä ja N kastelulannoituksena kasvukaudella
tutkittiin. Kokeessa verrattiin myös ravinteiden kertale-

vitystä jaksotettuun ravinteiden antoon. Maan ravinne-
tilaa seurattiin maa-analyysein. Porkkanoiden juuri- ja
naattinäytteet kerättiin kolme kertaa kasvukauden aika-
na. Tulokset analysoitiin kontrastianalyysillä ja osa tu-
loksista varianssianalyysillä faktorikokeena.

Porkkanan naattien ja juurien kuivapainot korreloivat
positiivisesti kaikkina näytteenottoaikoina molempina
vuosina (r a o.77***). Suuri yhteyttävä lehdistö tuotti
suuren juurisadon. Sijoituslannoitus lisäsi satoa verrat-
tuna pintalannoitukseen (p = 0.009**). Sato oli suurempi

151



koejäsenissä, joissa P ja K oli sijoitettu verrattuna koe-
jäseniin, joissaP:tä ja K:ta ei ollut annettu sijoituslan-
noituksena (p = 0.03*). Sadossa ei ollut eroa annettiin-
pa ravinteet yhdellä kerralla tai jaksottaen.

Sadonkorjuuvaiheessa lannoitus ei vaikuttanut pork-
kanan juurien kuiva-ainepitoisuuteen verrattuna lannoit-
tamattoraiin koejäseniin. Kuiva-ainepitoisuuden erot oli-

vat suuremmat eri vuosien välillä(p = 0.000***) kuin lan-
noitustapojen välillä (p = 0.05*). Kuiva-ainepitoisuus oli
suurempi koejäsenissä, joissa P ja K annettiin sijoitus-
lannoituksena ja N kastelulannoituksena kuin koejäse-
nessä, jossa kaikki ravinteet annettiin NPK-kastelulan-
noituksena.

152