P.D.Abeytilakarathna1 ,
R.M.Fonseka2 and J.P.Eswara2
1 Regional Agriculture Research and Development
Center, Bandarawela, Sri Lanka.
2 Faculty
of Agriculture, University of Peradeniya, Sri Lanka
ABSTRACT
An
experiment was conducted in the Agriculture Research Station at Rahangala, aim
to evaluate the effect of organic and inorganic fertilisers on growth and yield
performance of Strawberry cultivation under the sub-tropical condition in Sri
Lanka. The specific objectives of this study are, (i) to reduce Department of
Agriculture (DOA) recommended inorganic fertilizer rate without affecting the
yield and quality using compost and titonia green manure and (ii) study the
effect of organic and inorganic fertilizers on fruits quality and yield of
strawberries
The growth and yield performance of strawberry variety
“Chandler” was investigated by using nine different combinations of tithonia
green manure and compost with urea and muriate of potash (MOP). Experiment was
laid out as a Randomized Complete Block Design (RCBD) with 3 replicates.
Strawberry sets were planted in the open field (plot size is 3 x 2 m) with 30 x
40 cm spacing. DOA recommended amount of triple super phosphate (TSP),
agrochemicals and other cultural practices were used.
Weight of all berries, marketable berries and
nonmarketable berries were not significantly different during, when reduction of
the DOA recommended rate of urea and MOP by 25%, 50%, 75% ,100 % while increasing
tithonia at the rate of 2, 4, 6, 8 t/ ha respectively or compost at the rate of
2, 3, 4, 5 t /ha respectively. These combinations of inorganic fertilizers and
compost or tithonia did not affect to the average berry weight, number of
inflorescences per plant and the brix
value of ¾ coloured strawberry fruits.
Key words: Compost, Muriate of potash, Strawberry,
Tithonia, Urea.
INTRODUCTION
The use of inorganic fertilizer is high in the North
Central province followed by North Western, Uva and Eastern provinces due to
the higher extent of land under cultivation. Approximately 600,000 t of solid
fertilizers and 250,000 l of liquid fertilizers are imported to Sri Lanka
annually (Weerarathna, 2014). In year 2012, 0.30 million tons of Urea, 0.11
million tons of TSP, 0.10 million tons of MOP and 0.08 million tons of Ammonium
sulphate were imported to Sri Lanka (Weerarathna, 2014).
Strawbery
plants tend to grow out of the ground and develops poor root-soil contact with
age (Ellis et al., 2006) and dry soil
causes dying of new roots or root tips that are arisen from the crown of
strawberry plant (White, 1929). Therefore, mulching with straw and
incorporation of compost to the soil are required to conserve soil moisture and
soil structure that hasten the growth of roots. Strawberry plants feeds with
more nitrogen and potassium caused to increase number of runner production and
decrease the yield due to reduce the inflorescences number (Ellis et al., 2006). Therefore, it is important to reduce the
inorganic fertilizer while increasing the organic manures.
MATERIALS AND METHODS
Effect of 9 different
combinations of tithonia green manure and compost with urea and MOP (Table 3)
on the growth and yield performance of strawberry variety “Chandler” was
investigated. Experiment was laid out as a randomized complete block design
(RCBD) with 3 replicates. Strawberry sets were planted in open field. Plots
size was 3 x 2 m and plating space was 30 x 40 cm. DOA recommended amount of
triple super phosphate (TSP) and agrochemicals were used.
Four soil samples at
a depth of 0–15 cm were collected at different points from a block of the
experimental field before planting. The samples were bulked, air-dried and
screened through a 2 mm sieve. The soil pH was determined with the pH meter.
Exchangeable K was determined using flame photometer after the soil samples
were extracted in 1 M neutral ammonium acetate (NH4OAC). The total
nitrogen in soil and compost was determined by the Kjeldahl method. Available
phosphorus was determined by using spectrophotometer at 470 nm after extracting
in 0.03 M ammonium fluoride and 0.025 M HCl (Bray and Kurtz, 1945). Organic
matter percentage was determine ignition method (soil samples were kept in dry
oven at 105 0C temperature for 4 hours, followed by 4 hours kept in
muffle furnace at 400 0C temperature (Table 1). Proximate analysis
of the strawberry and Tithonia leaves
for NPK content was carried out using standard method (dry ash method for P
& K, Kjeldhal method for N) (Table 2). Tithonia diversifolia (fresh
leaves and soft stems) was chopped before use. Brix value of fruits was
measured by using brix meter.
Table 1. Soil
chemical properties of the field at ARS, Rahangala during the years of 2013 and
2014.
|
Soil chemical
property
|
Year 2013
|
Year 2014
|
|
pH (1:1 soil: water
)
Total N %
Bray P (ppm)
Exchangeable K
(ppm)
Organic matter %
|
5.8
0.12
10.5
112
2.1
|
5.7
0.11
11.2
117
2.1
|
Table 2. Chemical properties of compost and tithonia
used for strawberry trial at ARS, Rahangala during the years of 2013 and 2014.
|
Chemical property
|
Year 2013
|
Year 2014
|
||
|
Compost
|
Tithonia
|
Compost
|
Tithonia
|
|
|
N %
P %
K%
|
1.20
0.30
3.80
|
1.60
0.10
0.07
|
1.40
0.40
4.3
|
1.50
0.14
0.09
|
Table 3. Basal and top dressing fertilizer levels used
in different treatments for strawberries during 2013-2014.
|
|
Treatments
|
Basal dressing
kg/ha
|
Top Dressing kg/ha
|
||
|
2 & 3 MAP
|
6 MAP
|
8 MAP
|
|||
|
T1
|
DOA recommended inorganic
fertilizer (100% urea, TSP & MOP)
|
Urea 80, TSP 160, MOP 40
|
Urea 80, MOP 40
|
Urea 60, TSP 80, MOP 40
|
Urea 60, MOP 40
|
|
T2
|
75 % of urea & MOP, 100%
TSP & Tithonia 2 t/ha
|
Urea 60, TSP 160, MOP 30, Tithonia 500
|
Urea 60, MOP 30, Tithonia 500
|
Urea 45, TSP 80, MOP 30, Tithonia 500
|
Urea 45, MOP 30, Tithonia 500
|
|
T3
|
50 % of urea & MOP, 100%
TSP & Tithonia 4 t/ha
|
Urea 40, TSP 160, MOP 20, Tithonia 1000
|
Urea 40, MOP 20, Tithonia 1000
|
Urea 30, TSP 80, MOP 20, Tithonia 1000
|
Urea 30, MOP 30, Tithonia 1000
|
|
T4
|
25 % of urea & MOP, 100%
TSP & Tithonia 6 t/ha
|
Urea 20, TSP 160, MOP 10, Tithonia 1500
|
Urea 20, MOP 10, Tithonia 1500
|
Urea 15, TSP 80, MOP 10, Tithonia 1500
|
Urea 15, MOP 10, Tithonia 1500
|
|
T5
|
0 % of urea & MOP, 100% TSP &
Tithonia 8 t/ha
|
TSP 160, Tithonia 2000
|
Tithonia 2000
|
TSP 160, Tithonia 2000
|
Tithonia 2000
|
|
T6
|
75 % of urea & MOP, 100% TSP & Compost
2 t/ha
|
Urea 60, TSP 160, MOP 30, Compost 20t
|
Urea 60, MOP 30,
|
Urea 45, TSP 80, MOP 30,
|
Urea 45, MOP 30,
|
|
T7
|
50 % of urea & MOP, 100% TSP & Compost
3 t/ha
|
Urea 40, TSP 160, MOP 20, Compost 30 t
|
Urea 40, MOP 20,
|
Urea 30, TSP 80, MOP 20,
|
Urea 30, MOP 30,
|
|
T8
|
25 % of urea & MOP, 100% TSP & Compost
4 t/ha
|
Urea 20, TSP 160, MOP 10, Compost 40 t
|
Urea 40, MOP 20,
|
Urea 30, TSP 80, MOP 20,
|
Urea 45, MOP 30,
|
|
T9
|
0 % of urea & MOP, 100% TSP & Compost
5 t/ha
|
TSP 160, Compost 50 t
|
-
|
TSP 160
|
-
|
MAP- months after planting
Data collection and analysis
Growth, yield and quality
parameters such as weight of all berries per plant, weight of marketable
barriers per plant, weight of nonmarketable berries per plant, average fruit
weight, number of crowns, number of
runners, number of inflorescences, total solid content of ¾ coloured fruits. N,
P, K , pH were recorded. Percentage of organic
matter of compost and soil were measured at the beginning and end of the
experiment. Data were subjected to statistical analysis using AssiStat version 7.6
beta (2012) and R version 3.1.2 software.
Fig 1. Field
layouts of strawberry field trials at Agricultural Research Station of Rahangala during (a) 2013 and (b) 2014.
Fig 2.
Strawberry fruiting crop (a) at flowering stage and (b) red coloured
primary fruit, immature secondary and tertiary berries in fruit bearing stage.
Fig. 3. Incorporation
of tithonia for strawberry (a) before planting and (b) after planting. Tithonia
(c) tender stems and leaves and (d) chopping of tender stems
RESULTS
Yield performance of strawberries
The DOA recommended inorganic fertilizer and 25%, 50%,
75% ,100 % reduction of recommended rates of urea and MOP along with incorporation of tithonia 2. 4, 6, 8
t/ha respectively or compost 2, 3, 4, 5 t /ha respectively were observed
statistically similar yields for all berries, marketable berries or
nonmarketable berries during both years of 2013 and 2014 (Table 4).
Furthermore, the weight of total berries, marketable berries and non-marketable
berries obtained during year 2014 was higher than the year 2013.
Table 4. Yield
of strawberry grown with different level of urea, MOP, tithonia and compost
during 2013-2014.
|
Treatments
|
Yield (g/plant) during 2013
|
Yield (g/plant) during 2014
|
||||
|
Marketable berries NS
|
Non marketable
berries NS
|
All berries NS
|
Marketable berries NS
|
Non marketable
berries NS
|
All berries NS
|
|
|
DOA recommended
inorganic fertilizer (T1)
|
27.8
|
12.8
|
40.6
|
31.6
|
13.4
|
45.0
|
|
75 % of urea &
MOP, & Tithonia 2 t/ha (T2)
|
24.7
|
14.3
|
38.9
|
32.8
|
10.0
|
42.0
|
|
50 % of urea &
MOP, & Tithonia 4 t/ha (T3)
|
20.8
|
9.7
|
30.5
|
25.2
|
9.5
|
34.6
|
|
25 % of urea &
MOP & Tithonia 6 t/ha (T4)
|
28.0
|
13.3
|
41.2
|
46.3
|
17.9
|
64.2
|
|
0 % of urea & MOP & Tithonia 8 t/ha (T5)
|
27.4
|
12.8
|
40.2
|
40.6
|
15.6
|
56.2
|
|
75 % of urea & MOP & Compost 2 t/ha (T6)
|
20.8
|
14.1
|
34.9
|
54.7
|
13.4
|
68.1
|
|
50 % of urea & MOP & Compost 3 t/ha (T7)
|
31.5
|
16.2
|
47.6
|
46.3
|
15.4
|
61.8
|
|
25 % of urea & MOP & Compost 4 t/ha (T8)
|
20.4
|
9.9
|
30.2
|
45.0
|
16.5
|
61.5
|
|
0 % of urea & MOP & Compost 5 t/ha (T9)
|
15.5
|
9.6
|
25.1
|
30.8
|
12.7
|
43.5
|
|
CV%
|
67.4
|
53.6
|
61.1
|
32.6
|
34.3
|
31.7
|
NS –Not significant at p=0.05
Yield component of strawberries
Average fruit weight of strawberries
Every increment of compost by 1 t/ha from 2 t/ha basal
dressing or increasing the tithonia by way of 2 t/ha for every 25 % reduction
of recommended amount of urea and MOP were not affected to average fruit weight
of strawberries (Table 5).
Table 5. Average berry weight of strawberry grown with
different level of urea, MOP, tithonia and compost during 2013-2014
|
Treatments
|
All berries
|
|||
|
2013
|
2014
|
|||
|
Log transformed NS
|
Average weight (g)
|
Log transformed NS
|
Average weight (g)
|
|
|
DOA recommended
inorganic fertilizer (T1)
|
0.7953
|
5.3
|
0.8797
|
6.6
|
|
75 % of urea &
MOP & Tithonia 2 t/ha (T2)
|
0.8365
|
6.0
|
0.9020
|
7.0
|
|
50 % of urea &
MOP & Tithonia 4 t/ha (T3)
|
0.8522
|
6.1
|
0.8544
|
6.2
|
|
25 % of urea &
MOP & Tithonia 6 t/ha (T4)
|
0.8782
|
6.6
|
0.8576
|
6.3
|
|
0 % of urea & MOP & Tithonia 8 t/ha
(T5)
|
0.7680
|
4.9
|
0.9505
|
8.0
|
|
75 % of urea & MOP & Compost 2 t/ha (T6)
|
0.8454
|
6.0
|
0.8994
|
6.9
|
|
50 % of urea & MOP & Compost 3 t/ha (T7)
|
0.7755
|
5.0
|
0.9479
|
7.9
|
|
25 % of urea & MOP & Compost 4 t/ha (T8)
|
0.8378
|
6.0
|
0.9055
|
7.1
|
|
0 % of urea & MOP & Compost 5 t/ha (T9)
|
0.7402
|
4.6
|
0.9188
|
7.3
|
|
CV%
|
7.6
|
-
|
5.6
|
-
|
NS- Not significant at p=0.05
Numbers of inflorescences
Statistically, same number of inflorescences per plant
of strawberry were observed when increasing compost by 1 t/ha from the basal
dressing of 2 t/ha or increasing the tithonia by 2 t/ha along with reduction of
urea and MOP by 25 % (Table 6).
Table 6 Average
number of inflorescences of strawberry grown with different level of urea, MOP,
tithonia and compost during 2013-2014.
|
Treatments
|
Average number of
inflorescences/plant
|
|||
|
2013
|
2014
|
|||
|
Log transformed NS
|
Untransformed
|
Log transformed NS
|
Untransformed
|
|
|
DOA recommended inorganic
fertilizer (T1)
|
0.2299
|
0.7
|
0.2341
|
0.7
|
|
75 % of urea &
MOP & Tithonia 2 t/ha (T2)
|
0.3308
|
1.2
|
0.3089
|
1.1
|
|
50 % of urea &
MOP & Tithonia 4 t/ha (T3)
|
0.3192
|
1.1
|
0.3245
|
1.2
|
|
25 % of urea &
MOP & Tithonia 6 t/ha (T4)
|
0.2709
|
0.9
|
0.2651
|
0.9
|
|
0 % of urea & MOP & Tithonia 8 t/ha
(T5)
|
0.2732
|
1.1
|
0.2364
|
0.7
|
|
75 % of urea & MOP & Compost 2 t/ha (T6)
|
0.2996
|
1.0
|
0.3735
|
1.4
|
|
50 % of urea & MOP & Compost 3 t/ha (T7)
|
0.4327
|
1.7
|
0.1755
|
0.6
|
|
25 % of urea & MOP & Compost 4 t/ha (T8)
|
0.4025
|
1.5
|
0.2502
|
0.8
|
|
0 % of urea & MOP & Compost 5 t/ha (T9)
|
0.1693
|
0.6
|
0.2535
|
0.8
|
|
CV%
|
42.2
|
-
|
44.9
|
-
|
NS- Not significant
Effect of different treatments on soil N P K
The soil nitrogen percentages at the end of harvesting
season of strawberry were not significantly difference with the different
treatments during the year 2013. But there was a significant difference of nitrogen
at p=0.01 during the year 2014. Incorporation of tithonia at the rate of 2 to 8
t/ ha were seen higher soil nitrogen than the addition of compost at the rate
of 2 to 5 t/ha (Fig. 4).
A significantly higher Bray phosphorous was also found
in the treatment which was incorporated tithonia at the rate of 8 t/ha (6.6 ppm
Bray P) and the lowest P was observed in the treatments that was incorporated
compost at the rate of 3 t/ha (4.8 ppm Bray P) during the year 2013. However,
there was not any significant difference of soil P during the year 2014 (Fig. 5).
The highest soil potassium which significant at p=0.01, were found in the
treatment of DOA recommended inorganic fertilizer both during 2013 and 2014 (
132.3 and 133.3 ppm of K respectively).
The lowest K was seen in the treatments of compost at the rate of 5 t/ha and 25 % urea and MOP + compost 4 t/ ha
during both years of 2013 (82 and 81 ppm K respectively) and 2014 (89 and 86 ppm of K respectively)
(Fig. 6).
Fig. 4. Soil nitrogen percentages of different
treatments measured at the end of harvesting season of strawberry of the years
of 2013 & 2014
Fig. 5. Soil phosphate of different treatments
measured at the end of harvesting season of strawberry of the years of 2013
& 2014
Fig. 6. Soil
potash of different treatments measured at the end of harvesting season of
strawberry of years of 2013 & 2014
Total solid content of strawberry fruits
The brix value of ¾ coloured strawberry fruit were not
changed with increasing compost by 1 t/ ha after adding 2 t/ ha as basal
dressing or tithonia by 2 t/ha with
reducing recommended urea and MOP by 25 %
(Table 7).
Table 7. Total solid contents of strawberry grown with
different level of urea, MOP, tithonia and compost during 2013-2014
|
Treatments
|
Total solid content
of fruits
|
|||
|
2013
|
2014
|
|||
|
Log transformed NS
|
0Brix
|
Log transformed NS
|
0Brix
|
|
|
DOA recommended
inorganic fertilizer (T1)
|
0.7953
|
5.3
|
0.8797
|
6.6
|
|
75 % of urea &
MOP & Tithonia 2 t/ha (T2)
|
0.8365
|
6.0
|
0.9020
|
7.0
|
|
50 % of urea &
MOP & Tithonia 4 t/ha (T3)
|
0.8522
|
6.1
|
0.8544
|
6.2
|
|
25 % of urea &
MOP & Tithonia 6 t/ha (T4)
|
0.8782
|
6.6
|
0.8576
|
6.3
|
|
0 % of urea & MOP & Tithonia 8 t/ha (T5)
|
0.7680
|
4.9
|
0.9505
|
8.0
|
|
75 % of urea & MOP & Compost 2 t/ha (T6)
|
0.8454
|
6.0
|
0.8994
|
6.9
|
|
50 % of urea & MOP & Compost 3 t/ha (T7)
|
0.7755
|
5.0
|
0.9479
|
7.9
|
|
25 % of urea & MOP & Compost 4 t/ha (T8)
|
0.8378
|
5.9
|
0.9055
|
7.1
|
|
0 % of urea & MOP & Compost 5 t/ha (T9)
|
0.7402
|
4.6
|
0.9188
|
7.3
|
|
CV%
|
7.6
|
-
|
5.6
|
-
|
Ns- not significant
at p=0.05
DISCUSSIONS
Nitrogen requirement for strawberry are 166 kg/ha
(Albergts and Howard, 1982) or 168 kg/ha (DOA, 2010) for the total season
(200 days). Growers should avoid the temptation to apply of more nitrogen
because excess nitrogen can increase the amount of malformed fruits (Albergts
and Howard, 1982) and lead to excessive vegetative plant growth and reduce
yield. The maximum annual incorporation of organic fertilizer to the amount of
170 kg/ha nitrogen due to excessive use of organic fertilizers can lead to
adverse effects such as nitrogen leaching in to ground water, release of heavy
metal and harmful organic substances in to soil, spread of weeds, soil
pollution with harmful microorganisms etc.
(Council of Directive, 1991). Nitrogen 1.3% and potassium 4.1% were
contained in the compost while nitrogen 1.6% and potassium 0.1 % were contained
in the leaf and tender stems of tithonia (Table 2) on dry matter basis.
According to Jama et al., (2000), the green leaf biomass of tithonia was
high in nutrient, average about 3.5% N, 0.37 % P and 4.1 % K on dry matter
basis. The advantage of incorporating tithonia biomass was the rapid
decomposing after application to the soil and incorporating biomass can be
effective for source of N, P, K for crops. Because of high labour requirements
for cutting & carrying the biomass to field, the use of tithonia biomass as
a nutrient source is more profitable with high value crops like strawberries
(Jama et al., 2000). Ikerra et al., (2006), noted that the yield
of corn grains was increased significantly with the application of 5 t/ha of
this green manure. Similar effect was found in Asian rice Jama et al.,
2000. In both cases authors associated
the beneficial effect of this manure with increments produced by it on the pH
and on the exchange calcium, as well as with the decline of exchangeable aluminum
and with the absorption capacity of phosphorus in the soil. The beneficial
effect of green manures on improvements of the soil properties and on rice
areas were indicated by Kumar et al., (2003). These authors attributed
it mainly to the beneficial effect of the green manures on the percentage of
stable aggregates to the water and to the increase of the organic matter
content. Tithonia biomass was also recognized as an effective source of
nutrient resulting in improved yield of Brassica oleraceae in nitrogen
limiting soil (Onyango and Onyango, 2002).
DOA recommended rate of inorganic fertilizers give
nitrogen at the rate of 168 kg /ha and potassium at the rate of 99.6 kg/ha
(Table 3). When reducing the DOA recommended urea and MOP by 25%, 50% and 100%;
nitrogen was received 126, 84, 42 and zero kg/ha and potassium was received
74.7, 49.8, 24.9 and zero kg/ha respectively. In our treatments, the DOA
recommended urea and MOP were reduced by way of 25%, 50%, 75% ,100 % with adding
tithonia 2, 4, 6, 8 t/ha or compost 2, 3, 4, 5 t /ha respectively. This
combination of urea and tithonia were caused to receive the total nitrogen by
6.5, 13.1, 19.6 and 26.2 relative percentage respectively lower than the DOA
recommended rate. Potassium was received by 23.2, 46.4, 69.6 and 92.8 relative
percentages respectively. This lower than the DOA recommended rate of potassium
from the combination of MOP and tithonia. The combination of reducing MOP while
increasing compost were caused to increase the addition of extra potassium by
8.3, 72, 87.7 and 103.3 relative percentage than the DOA recommendation. But
the combination of reducing urea while increasing compost was resulted reduce
nitrogen receiving by 9.5, 26.8, 44 and 61.3 relative percentage than DOA
recommendation. Wen et al., (1997) also stated that the application of
compost had a positive effect on the concentration of available potassium.
When consider the yield and yield components, the DOA recommended inorganic fertilizer and urea
and MOP by way of 25%, 50%, 75% ,100 % reduction from recommended amount
incorporating with tithonia 2. 4, 6, 8 t/ha respectively or compost 2, 3, 4, 5
t /ha respectively produce similar yields for
all berries, marketable berries or nonmarketable berries during both
years of 2013 and 2014 (Table 4) and the
total, marketable and non marketable yields obtained during year 2014 was
higher than the year 2013. This combination of inorganic fertilizers and
compost or tithonia did not effect to the average berry weight (Table 5),
number of inflorescences per plant (Table 6) and the brix value of ¾ coloured
strawberry fruits.
Triple super phosphate at the rate of 240 kg/ha (48.6
kg P /ha) were applied according to the DOA recommendation (2010) for all the
treatments combinations (Table 3). But
Compost had 0.35 % P and Tithonia had a 0.12 % P (Table 2). Therefore when
addition of tithonia the rate of 2, 4, 6 and 8 t/ ha, the extra P was added by
4.9, 9.9, 14.8 or 19.8 relative percentage respectively than the DOA
recommendation while addition of compost
at the rate of 2, 3, 4 and 5 t /ha was caused to add extra P by 14.4, 21.6,
28.8 or 36 relative percentage respectively than the DOA recommendation. Reduction
of recommended urea and MOP by 25 %
while increasing compost by 1 t/ha after adding 2 t/ha at the time of plant
establishment or increasing tithonia by 2 t/ ha did not effect brix value of ¾
coloured strawberry fruit.
CONCLUSIONS
Strawberry yield did
not reduced significantly with the reduction of DOA recommended urea and MOP by
way of 25%, 50%, 75% ,100 % along with addition of tithonia 2, 4, 6, 8 t/ ha or compost 2, 3, 4,
5 t / ha respectively. Therefore, 25% inorganic fertilizer could be reduce from
recommended rate of urea and MOP by adding tithonia or compost at the rate of 2
t/ha.
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