V. Nalliah,
R. Sri Ranjan Ph.D., P.Eng.
DEPT. OF BIOSYSTEMS ENGINEERING
UNIVERSITY OF MANITOBA
WINNIPEG
CANADA
CSBE/SCGAB 2008 50th Annual Conference
Vancouver, British Columbia
July 13 - 16, 2008
 Water conservation is important in irrigated agriculture
 limited water resources
 losses during irrigation
 competition for water among the different users
 Improving the sustainability of water resources
 A potential solution is micro irrigation
 frequent water application in small flow rates either on or
below the soil surface
 Drip, bubbler, spray jet, and subsurface irrigation systems
Types of irrigation in Canada

49.8% sprinkler irrigation

23.2% travelling gun

13.1% drip system and

13.8% other irrigation systems such as flooding and
subsurface irrigation

Lower risk of evaporation, runoff losses from the soil
surface

Greater savings of water, nutrient, and labor

Fewer chances for foliage diseases

More uniform plant growth

Very adaptable to different soil conditions

Gives a better chance to optimize the use of fertilizer
and other chemical applications, and

lower rate of weed growth
•No pumping needed
•Low installation cost
•Undemanding operator
expertise and system
maintenance
Plant pot
Emitter
H
Water source
Schematic representation of the capillary irrigation system for container
grown plants

Livingston (1908) introduced the negative pressure
concept with porous clay cups

Richards and Loomis (1942) studied the performance
of improved double-walled irrigator pots suitable for
low flow rates and tension

Kato and Tejima (1982) performed a theoretical
analysis in subsurface irrigation on the basis of
different negative pressures

Lipiec et al. (1988) proposed a porous tube negative
pressure water circulation technique suitable for
measuring plant water uptake continuously under
laboratory conditions
A
study on the efficiency of subsurface irrigation
under various elevation differences by Jiang et al.
(2004)
tested various pressures ranging from 0.5 m positive
pressure to 4.0 m negative pressure
 water infiltration into soil was observed up to 2.0 m soil
depth without applying any pressure to the system

A
soil-cooling and auto-irrigating system by Liu et
al. (2006)
simultaneously irrigating and cooling the soil
 used porous ceramic pipes
 electric pump was used to maintain the pressure

 To
compare the yield and quality of hot pepper
using capillary irrigation systems under
different negative pressures.
 To
optimize the pressure of the system for
producing pepper under controlled
environment.
PES membrane
on the disc
Perforated
acrylic discs
Plexiglass tube
connected to the cup
Initial
setup
As growth
progressed...

Jalapeno hot pepper (Capsicum annuum) was grown
in a controlled-environment
 -0.20, -0.40, -0.60 m negative pressure irrigation, and
hand-watered treatments

A Completely Randomized Design (four treatments
replicated seven times)

The four irrigation treatments received the same
experimental conditions (light, temperature, RH)

Measurements taken were:


Plant height, number of leaves, leaf area, water
consumption, and plant and fruit biomass
Hotness of pepper fruits was quantified using HPLC

Capsaicinoids are responsible for hotness of pepper

Capsaicinoids – Capsaicin & Dihydrocapsaicin

The ground oven-dried fruits were used to extract the
capsaicinoid using acetonitrile by heating at 800C for
4h

An Agilent-1100 series HPLC system with 4.6x250 mm
Eclipse XDB-C18 column was used

Standards of capsaicin and dihydrocapsaicin were used
to identify and quantify the concentration of
capsaicinoid in samples
PLANT HEIGHT
LEAF NUMBER
LEAF AREA
Total water consumption, biomass yields, and
WUE of hot pepper plant
Irrigation
treatments
Hand water
Means and SE of the four treatments [a]
Irrigation
Dry shoot
Fresh root
Dry root
water use Fresh shoot
(kg)
(g)
(g)
(g)
(g)
6.770
44.73a ±1.63 6.20ab ±0.19 2.18a ±0.17
1.50a ±0.19
WUE
(g/kg)
1.14a ± 0.05
-0.2 m pressure
4.437
45.16a±1.55
6.67a ±0.49
1.94a ±0.21
1.20ab ± 0.13 1.78b ± 0.14
-0.4 m pressure
2.335
32.51b ±1.73
5.39b ±0.22
1.41b ±0.18
0.98b ±0.11
2.73c ± 0.09
-0.6 m pressure
1.802
24.93c ±2.13
4.44b ±0.35
1.20b ±0.13
0.80b ±0.11
2.93c ± 0.30
Means in the same column followed by different letters are significantly different using
LSD at P < 0.05.
[a]
Effect of two irrigation treatments on fruit biomass, fruit
size, and water use efficiency (WUE)
Jalapeno hot pepper fruit biomass and size[a]
Total
fresh fruit
Irrigation
treatments
[a]
Total dry
fruit
Fruit
length
Fruit
diameter
WUE
(g)
(g)
(mm)
(mm)
(g/kg)
Hand
watering
42.48 a
3.69 a
44.5 a
18.9 a
6.27 b
-0.2 m
pressure
41.40 a
3.59 a
44.3a
18.1 a
9.33 a
Means followed by the same letter in the same column are not significantly different using LSD at P
< 0.05.

Jalapeno hot pepper was able to grow well under
capillary irrigation systems

Continuous water supply in the system eliminated the
need for larger soil depth to store water

The plant height, leaf number, leaf area, and plant
biomass were significantly higher in the -0.2 m and the
control irrigation treatments compared to the -0.4 and
-0.6 m treatments

The vegetative growth parameters were not
statistically different between -0.2 m and the control
irrigation treatments

The reproductive growth parameters (fruit length,
diameter, and fruit biomass) in the -0.2 m capillary
irrigation treatment were also comparable to the
control treatment

The hotness of fruits in water starved plants were
greater than in the plants under sufficient water

The -0.2 m negative pressure irrigation had better
performance in terms of growth and yield parameters
when compared to the manual irrigation while saving
a considerable amount of water

The system is simple, inexpensive, water saving, and
reproducible with minimum labor requirements for
container grown plants

Manitoba Agri-Food Research & Development
Initiative (ARDI)

Dr. Aluko Rotimi (Dept. of Human Ecology, University of
Manitoba)

Ms. Amarbeer Bandari (Richardson Centre for Functional
Foods and Nutraceuticals, University of Manitoba)

Dr. R. Zakaluk (Civil Engineering & Technology Department,
Red River College, Winnipeg, Canada)
Questions?