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 ColumbiaJuly 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

Emitter

Plant pot

Water source

Schematic representation of the capillary irrigation system for container grown plants

H

•No pumping needed

•Low installation cost

•Undemanding operator expertise and system maintenance

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.

Perforated acrylic discs

PES

mem

bra

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n

the d

isc

Plexiglass tube connected to the

cup

As growth progressed...

Initial setup

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

Irrigation treatments

Irrigation water use

(kg)

Means and SE of the four treatments [a] Fresh shoot Dry shoot Fresh root Dry root WUE

(g) (g) (g) (g) (g/kg)Hand water 6.770 44.73a ±1.63 6.20ab ±0.19 2.18a ±0.17 1.50a ±0.19 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

Total water consumption, biomass yields, and WUE of hot pepper plant

[a] Means in the same column followed by different letters are significantly different using LSD at P < 0.05.

Irrigation treatments

Jalapeno hot pepper fruit biomass and size[a]

WUE Total

fresh fruit Total dry fruit

Fruit length

Fruit diameter

(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

[a] Means followed by the same letter in the same column are not significantly different using LSD at P < 0.05.

Effect of two irrigation treatments on fruit biomass, fruit size, and water use efficiency (WUE)

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?