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1Performance of Irrigated and Non-Irrigated Oil Palms

Literature Review : Performance of Irrigated and Non-Irrigated Oil Palms

The growth and production of oil palms are known to be influenced by the

variations in climatic conditions especially by the rainfall distribution in Malaysia.

Although Malaysia has copious rainfall, there are certain areas which are drier thanthe rest due to the differences in the land’s geography such as inland areas which

are sheltered by mountain ranges and are relatively free from its influences. This

will influence the ratio of female to male inflorescence by decreasing the number of

female inflorescence and promoting inflorescence abortion. These might due to the

differential costs of producing male inflorescence versus female inflorescence, size

of the palm and also the relationship between sink and source. Water stress in oil

palms could also effect the oil palm yield by affecting the bunch ripening and oil

accumulation in the bunches. In addition to that, the decline in the physical state of

the oil palm could also be seen when palms are subjected to water stress. These

include an increase in vegetative disorders (accumulation of unopened leaves,

premature drying out of lower leaves, broken green leaves, drying out of bunches

and toppling of the entire canopy or in the worst case, die), decrease in trunk size,

stunted young palms and declining frond production of about 4% to 12% as

compared to a wet site. This is due to the limitation in the nutrient uptake by the oil

palm since the nutrients are taken in from the soil solution. Low availability of water

in the soil will cause the remaining available water and nutrients to be tightly held

within the soil matrix. Besides that, water stress in oil palms will also induce the

closure of stomata and thus reducing the transpiration and photosynthesis rate.

Water deficiency in oil palm could also lead to the unavailability of nutrients

in the soil solution. Since oil palm absorbs nutrients in the form of solution, it is

vital that the soil has adequate water to dissolve the nutrients. Based on an

experiment done by FELDA (2000) showing the effects of fertilizers on irrigated and

non-irrigated, it is proven that irrigation has a positive affect on frond production,

frond length, dry weight and leaf area as compared to non-irrigated site. Besides

that, there is also an increase in bunch weight which directly influences the FFB

yield which showed an increase of 35%. The yearly rainfall in the area also

influences the FFB yield as too much rainfall coupled with irrigation will reduce the




FFB yields due to excessive water in the soil which causes leaching and runoff of

nutrients. This can be seen in the graph below where the rainfall exceeded 2000mm

per year in 2006 AND 2010, the FFB yield declined. Although oil palm can tolerate

rainfall up to 5,000mm per year, the soil must be properly drained in order for the

oil palm to sustain its production. Overall, the FFB yield was higher and better in

the irrigated plot as compared to non-irrigated plot.

In order to prevent water stress in oil palms especially in the drier regions,

irrigation set ups are proposed. There are many types of irrigation which can be

used such as overhead spray, overhead sprinkler, layflat perforated polythene tube,

drip irrigation and furrows. The advantages and disadvantages of the irrigation

types mentioned above are listed in the following table.

Table 1: Advantages and disadvantages of different types of irrigation.

Irrigation Type Advantages Disadvantages

Overhead Spray –

Mist System

(Sumishower)

The mist distributed in

a square.

Delivered in fine mist

for better penetration

into the soil.

No fertilizers wash off

from the bad.

Easy for cleaning.

Can be used on

undulating terrain.

Creates larger wetted

area.

Clogging of filter that

requires frequent cleaning.

Strong wind velocity affects

the water distribution.

Require more piping.

High initial cost to set up.

May have blind spot if fitted

at wrong angle.

Frequent cleaning is

required if water is dirty.

Overhead Sprinkler Uniform watering.

Less blockage.

Easy to maintain.

Reusable.

Can deliver necessary

High capital cost.

Larger water droplet size.

Require more piping.




amounts of water.

Able to adapt to the

size of the field.

Layflat Perforated

Polythene Tube

Very fine mist droplet.

No ‘hardcapping’.

Low pressure

requirement.

Low capital cost.

Need a level base & free of

hard/sharp article.

Wind drift.

Blockages.

Interference by growing

fronds.

Require clean water.

Require sufficient pressure.

Water jet may be impededby tall seedlings.

Regular flushing required to

prevent clogging.

Drip Irrigation Provide localized

irrigation pattern with

high WUE and fertilizer

use efficiency.

Reduce the growth of

weeds between plant

rows.

Medium maintenance.

Reduce labor needs

and energy.

Digging trenches for dripper

lines close to palm causes

root damage.

Do not prevent

intercropping irrigation.

No micro-climate cooling

effect.

High filtration and water

quality demands.

Difficult inspection during

irrigation.

High initial costs.

Furrows Provide on-farm water

management flexibility

under many surface

irrigation conditions.

Medium maintenance.

Low WUE and fertilizer use

efficiency.

No mirco-climate cooling

effect.

Low water distribution.




Low filtration and

water quality

demands.

Easy inspection during

irrigation.

Low primary

investment.

High erosive potential of

the flow.

Difficulty in moving farm

equipments.

Evaporation from water

surface.

Implementing irrigation system in oil palm plantations proves to be beneficial

not only to the oil palm itself but also to the estates in the long run. This can be

seen in the physical conditions of the oil palm whereby there is an increase in the

girth size and leaf area. The girth size of the oil palm is important as the trunks acts

as sinks during immature stage and as a buffer during maturity so that the bunches

are able to retain nutrients. A higher photosynthesis rate will also be recorded as

the leaf area increases. This means that the palm will be able to produce more

assimilates which in return will increase the bunch number and to a lesser extent,

heavier bunch weight. This can be seen where FFB yields increased by 12.8%

totaled over the 3 ½ years of planting (Lee, Nga, Romzi and Ismail, 2005).

Providing adequate amount of water to the oil palm through irrigation methods can

also produce denser and healthier canopies that are able to shade the ground

better to prevent weeds and reduce water loss from the soil. Proper irrigation could

also increase the production of frond number by 18% (5-6 fronds/palm), during

years where the dry spell is more prominent. Besides that, the amount of oil

produced per palm will also have a significant increase as the kernel to bunch ratio

is recorded to increase by 10%. In the long term, the plantation will be able to

sustain yields of 30-36 t/ha for more than 10 years. In an experiment by Lee et. al.

(2005), the yield response to irrigation in a drier region with poor soils condition

was much higher at 73% but in a moderately wet region, it showed a 35% higher

yield response. However, yield responses to irrigation are subjected to the humidity

level at that point of time as low humidity will restrict photosynthesis and thus

reduces the responses.




The main challenges in implementing large scale irrigation are inadequate

water supply and also unsuitable terrain. Inadequate water supply poses a huge

challenge to us especially in the inland area due to the small amount of rainfall and

also the difficulty in looking for a good water source. Unsuitable terrain such as

uneven ground, terraced areas and slopes also influence the choosing and

implementation of irrigation.

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