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The experiment entitled “Wicking bed irrigation in tomato (Solanum
lycopersicum (L).)” was conducted with the objectives to standardize the height and
media filled reservoir in wicking bed system, to evaluate the performance of tomato as a
test crop under wicking bed (WB) system and to work out the economics. The
experiment was carried out from December 2020 to April 2021 in farmer’s field at
Varkala in Thiruvananthapuram district.
The experiment was laid out in completely randomized design with 8 treatments
replicated thrice. The treatments were T1 – gravel WB 100mm + geotextile inter liner
(GT) + soil bed (SB) 200 mm; T2 - gravel WB 150mm + GT + SB 300 mm; T3 - coconut
shell WB 100 mm + GT + SB 200 mm; T4 - coconut shell WB 150 mm + GT + SB 300
mm; T5 - gravel + coconut shell (1:1) WB 100 mm + GT + SB 200 mm; T6 - gravel +
coconut shell (1:1) WB 150 mm + GT + SB 300 mm; T7 - SB 200 mm conventional
irrigation; T8 – SB 300 mm conventional irrigation. Soil bed was prepared by mixing soil,
coir pith compost and FYM in the ratio 2:1:1. Nutrition was provided as per the organic
POP of KAU. Tomato seedlings of variety Vellayani Vijai was used for transplanting. After
transplanting, all treatments were surface irrigated for two weeks. Irrigation was given in
the wicking bed based on the water level in the reservoir.
The growth characters viz., plant height, number of branches, stem girth and leaf
area were recorded at 30, 60, 90 days after transplanting (DAT) and at harvest. At 30
DAT and 60 DAT, taller plants (59.32, 93.25 cm, respectively) were observed in coconut
shell WB 150 mm + GT + SB 300 mm (T4) and at 90 DAT and at harvest gravel +
coconut shell (1:1) WB 150 mm + GT + SB 300 mm (T6) recorded the taller plants.
Number of primary branches per plant were higher in the treatment coconut shell WB
150 mm + GT + SB 300 mm (T4) in all the growth stages. Stem girth was not influenced
by the wicking bed and surface irrigation treatments except at 60 DAT. At 60 DAT, stem
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girth recorded in all the treatments were on par, except soil bed 200 mm with
conventional irrigation (T7). Leaf area was not influenced during early stages of growth.
Higher leaf area (797 cm2
) was observed for T2 at 90 DAT and at harvest (768 cm2
).
Coconut shell WB 150 mm + GT + SB 300 mm (T4) recorded higher dry matter, root
weight and root volume. The longest roots (17.30 cm) were recorded in gravel WB
150mm + GT + SB 300 mm (T2).
Flower clusters per plant was significantly more in T2 (31.67) which was on par with
T1, T5 and T6. Coconut shell WB 150 mm + GT + SB 300 mm (T4) recorded higher
number of flowers per cluster (10.67). The treatments, coconut shell WB 150 mm + GT +
SB 300 mm (T4) and gravel + coconut shell (1:1) WB 150 mm + GT + SB 300 mm (T6)
took less number of days (37.83) to reach 50 per cent flowering. Fruits were longer (4.35
cm) in T3 and fruit diameter was higher (11.63 cm) in T6. T4 (coconut shell WB 150 mm
+ GT + SB 300 mm) recorded more fruit weight (41.50 g) and remained statistically on
par with T2 and T6.
The analysed data revealed that higher yield per plant (1153 g) and more number of
pickings were recorded in T4 which was on par with T2. Harvest index was higher in
larger reservoir depths. Significantly higher (20.64 mg 100 g fruit-1
) ascorbic acid content
was recorded in T4 and T5. Total soluble sugars and titrable acidity were not influenced
by wicking and surface irrigation treatments.
Soil pH, organic carbon, P and K content were not influenced by wicking bed and
surface irrigation treatments. Bulk density was higher (1.31 Mg m-3
) in gravel + coconut
shell (1:1) WB 150 mm + GT + SB 300 mm (T6) which was on par with T3 and T5.
Surface irrigation treatments (T7 and T8) recorded lower EC value (0.86 and 0.95 dS m-1
,
respectively). Available nitrogen content was significantly higher in T4 (coconut shell
WB 150 mm + GT + SB 300 mm) and was comparable with T1 and T5. Plant uptake of N
and P was higher in T4 (coconut shell WB 150 mm + GT + SB 300 mm) and K uptake
was higher (10.18 g per plant) in T2 (gravel WB 150mm + GT + SB 300 mm) which was
on par with T4.
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Water requirement of tomato varied with the treatments ranging from 480.06 mm (T4)
to 568.22 mm (T7). The frequency of irrigation varied from 9 in larger reservoir depth to
35 in surface irrigation treatments. T4 recorded the lowest water requirement (480.06
mm) and the highest total water use efficiency (65.05 kg ha-1 mm-1
). The economic
analysis revealed that T4 (coconut shell WB 150 mm + GT + SB 300 mm) recorded the
highest net returns per plant (₹ 46.23) and BCR of 2.00.
From the study, it could be concluded that, tomato can be successfully cultivated in
wicking bed system. Among the wicking beds, coconut shell filled reservoir of 150 mm
depth + geotextile inter liner + 300 mm soil bed depth could be recommended for tomato
cultivation considering the yield, quality, water use efficiency and economics.