沙漠研究 19-1, 265- 267 (2009 )Journal of Arid Land Studies“Desert Technology IX ”
Refereed Paper

Study on Subsurface Irrigation Using Ceramic Pitcher
on Tomato Cultivation in Greenhouse-Effect of Water Pressure inside Ceramic Pitcher on Soil Moisture and Tomato GrowthJining ZHANG1, Hirotaka SAITO1, Makoto KATO1
Abstract: We investigated the impact of enforcing different water pressure values (10, 0, -30and -50 cmH2O) in the buried ceramic pitcher at 20cm depth below the soil surface on soil
moisture movement and tomato growth in the greenhouse for subsurface irrigation. By
decreasing the water pressure, the soil volumetric moisture content and tomato yield decreased,water use efficiency (WUE) increased. The volumetric moisture content decreased with timein the later stage because ceramic pitcher’s hydraulic conductivity became lower. Numericalsimulation using the HYDRUS-2D code agreed well with the experimental results.
Key words: Ceramic pitcher, HYDRUS-2D, Subsurface irrigation, Tomato, Water pressure

1. Introduction
Water is becoming scarce in arid and drought prone areas. Scarce water limits economic
development of these regions. Ceramic pitcher irrigation, one of the traditional subsurface irrigation
methods, is used with water-filled unglazed baked ceramic pitchers, which are buried to their necks in thesoil. Ceramic pitcher irrigation is very attractive for the following reasons: inexpensive, water-saving,easy to operate, and suitable for uneven terrain (Mondal et al., 1987). In this study, the ceramic pitcher
was buried entirely in a tomato field to evaluate the performance as an underground water emitter for
subsurface irrigation. The main objectives of this study are 1) to investigate the effect of different watersupply pressures on the changes in soil volumetric moisture, yield, and water use efficiency (WUE) for
tomato cultivation, and 2) to develop a cultivation system in which soil moisture content can be
automatically controlled using the ceramic pitcher subsurface irrigation system.
2. Materials and Methods
2.1 Properties of soil and ceramic pitcher
This work was conducted in a greenhouse at the field research station of the Tokyo University ofAgriculture and Technology in Fuchu, Tokyo, Japan. The soil collected at the station was classified as
volcanic ash soil, Andisol. The saturated hydraulic conductivity is 6.0 cm d-1. Figure 1 showed aschematic diagram of the ceramic pitcher used in this study. The length, the outer radius, and the inner
radius of the pitcher are, respectively, 15 cm, 4 cm, and 3 cm. The saturated hydraulic conductivity is0.012 cm d-1.
48cm

20cm

Length,
15cm

8cm
15cm
Marriotttank

Inner radius, 3cm

H

55cm

Andisol

Delivery pipe

Outer radius, 4cm
Filter layer

5cm

37cm

Fig.1. Diagram of the ceramic pitcher.
1Fig.2. Schematic diagram of the experiment’s apparatus.

Graduate School of Agriculture, Tokyo University of Agriculture & Technology, Fuchu, Tokyo 183-8509, Japan266

2.2 Experimental setup
Four experimental treatments were designed with different water pressures (10, 0, -30 and -50
cmH2O). The apparatus used for the experiment layout was presented schematically in Figure 2. A
conical bucket used in this study had a 5 cm-thick sand filter layer in the bottom. A mixture of Andisoland compost were uniformly added and compacted to achieve a uniform dry bulk density of 0.70 g cm-3,and a uniform volumetric moisture content of 0.40 cm3 cm-3.
A ceramic pitcher was buried at 20 cm below the soil surface. ECH2O soil moisture sensors(DECAGON Devices, Inc., USA) were also installed at 10, 30, and 40 cm depth to monitor the variation in
the volumetric soil moisture content. Two tomato plants (Takai momotaro T93) were transplanted into thepot on May 11th, 2007. A constant water pressure was applied to the pitcher during the tomato growing
season. After tomato fruits were harvested, the water supply was stopped before the termination of theexperiment on August 10th, 2007.
2.3

Numerical simulation
The HYDRUS-2D (Simunek et al., 1999) code simulates variably saturated water flow in porous
media by solving the mixed form of the Richard equitation using a Galerkin finite-element method. We
used HYDRUS-2D to simulate the infiltration process around the buried ceramic pitcher. The suitabilityof the model was assessed on the basis of the comparison between simulation results and experimental
observations of soil volumetric moisture contents.

3.1

Soil volumetric moisture contentFigure 3 presented variations of thevolumetric soil moisture content at different waterpressures during the tomato growth period (90days). The water pressure decreased, thevolumetric soil moisture content became less at agiven depth. In all the cases, changes in thevolumetric soil moisture contents could be divided
into three phases. During the first phase (0～200.50
3So i l vol um et ric mosi t ure co nte n t (cmcm-3 )3. Results and Discussion
Data were not accurately collected for thewater pressure of 10 cmH2O. We therefore only
show the results of 0, -30, -50 cmH2O water supply
pressures in the remainder of the paper.

0.45

0.40

0.35

0.30

0.25

0 c mH2 O
0.20
01020304050607080
Time (Day )

90

0.50

0.5 0

M eas ured 10 cm H2O

M easu red 10 cm H 2O
Simulated 10 cm H 2O
M easu red 30 cm H 2O
Simulated 30 cm H 2O
M easu red 40 cm H 2O
Simulated 40 cm H 2O

0.4 5

0.4 0

Soil v olumetric moisture content (cm3 cm -3)

3
S oil volumetric mois ture co ntent (cmcm- 3)

M eas ured 1 0 cm H 2O
Simulated 10 cm H 2O
M eas ured 3 0 cm H 2O
Simulated 30 cm H 2O
M eas ured 4 0 cm H 2O
Simulated 40 cm H 2O

0.3 5

0.3 00.2 5

Simulated 10 cm H 2O
M eas ured 30 cm H2O
Simulated 30 cm H 2O
M eas ured 40 cm H2O
Simulated 40 cm H 2O

0.45
0.40
0.35
0.30
0.25
-50 c mH2O-30 cmH 2O

0.20

0.2 00102030

4050607080

90Time (D ay )01020304050607080

Time (Day)

Fig. 3. Variation of measured and simulated soil moisture content for 10cm, 30cm and 40cm soil depth.

90267days), changes were around the pitcher (depth of 30 and 40 cm) for all three cases, while the volumetricmoisture contents relatively small decrease dramatically at the depth of 10 cm for all three cases. In thenext phase (20～45 days), the volumetric content decreased significantly, probably because root water
uptakes by tomato and root extension were greater during this phase. At the same time, the volumetricsoil moisture content decreased because the pitcher was covered by roots that take water directly from thepitcher. And then, in the final phase (45～90 days), the volumetric soil moisture contents were in generalinvariant and were almost at their steady states.
Figure 3 compared simulated and measured values of the soil volumetric moisture content for 10, 30,
and 40 cm below the soil surface, respectively. To account for direct water uptake from the pitcher byroots covering the pitcher, in numerical simulation we modified the boundary condition during the second
and third phases by decreasing the water pressure from 0, -30, and -50 cmH2O, to -500, -700, and -800
cmH2O, respectively. In general, the simulated values were in good agreement with the observations.
3.2

Tomato yield
Table 1 showed the tomato yield at all investigated water pressures. The 0 cmH2O water pressurecase had the best yield. The main reason for increasing the tomato yield was soil moisture content. The
0 cmH2O water pressure case depleted more water, resulted in higher tomato yield. The relationshipbetween the water supply pressure and the tomato yield revealed that the smaller pressure decreased thesoil moisture content, and then decreased consequently the tomato yield.
3.3 Water use efficiency
Table 1 also showed the water use efficiency (WUE), which was obtained from dividing the total
fresh tomato yield by the total amount of water supplied. It is useful to identify the best irrigation
scheduling strategies. -50 cmH2O water pressure gave the highest WUE. Improving irrigation method
and increasing WUE in arid and semiarid region is important for water resource protection. It can be said
that although the tomato yield of water pressure of -50 cmH2O was not the highest, the WUE was the best.
Table 1. Tomato yield and water use efficiency at different water pressures.

Water pressure (cmH2O)

Tomato yield (kg pot-1)

WUE (kg m-3)

0-30
-50

1.17
1.06
0.95

24.9
32.1
32.8

4. Conclusions
A study of water seepage from the subsurface ceramic pitcher in Andisol under different waterpressures was executed in a greenhouse of Tokyo University of Agriculture and Technology, Tokyo, Japan.
While the soil volumetric moisture content and tomato yield decreased, WUE increased as the waterpressure decreased. The volumetric moisture content decreased with time in the later stage because
ceramic pitcher’s hydraulic conductivity became lower. Numerical simulation results obtained using theHYDRUS-2D code agreed well with the experimental results. Consequently, it can be said that low
pressure irrigation can save water and improve water use efficiency. The subsurface irrigation systemutilizing ceramic pitcher would be a useful and practical technique for vegetable production in arid andsemi-arid regions.
References
Mondal R.C., Gupta S.K., Dubey S.K. (1987): Pitcher irrigation. Central soil salinity research institute, Karnal-132001, India.
Simunek J., Seina M., van Genuchten M.Th.(1999) The HYDRUS-2D software package for simulating the two dimensional movementof water, heat and multiple solutes in variable-saturated media, IGWMC-TPS 53, version 2.0, Int. Ground Water Modeling Center,Colorado School of Mines, Golden, Colorado.
Zhang J., Nagasawa K., Suzuki S., Nishimura T., Kato M. (2007): Development of Subsurface irrigation technology by utilizing
Ceramic Pitcher- Effect of Pressure on Soil Moisture Movement inside Ceramic Pitcher-. Journal of Arid Land Studies,
17(3):113-122.