Land and Water Link
November 2003
 Good
Oil for PNG Producers
Visitors to Port Douglas in north Queensland would recollect the enormous
palms forming a grand colonnade to the coastal community. Although not
a commercial crop in Australia, the oil palm is Papua New Guinea’s
(PNG) most valuable agricultural commodity, outranking coffee at annual
export value of A$152 million in 2002.
In the early stages of palm cultivation in PNG’s West New Britain,
oil palms developed ‘Orange Frond’ symptoms, characteristic
of magnesium deficiency. An essential nutrient for all plants, magnesium
has a major role in photosynthesis, is important for the transfer of energy
within the plant and it promotes oil production. Magnesium deficiency
results in poor plant growth and reduced productivity.
The PNG Oil Palm Research Association (PNGOPRA) carried out numerous
trials with kieserite, a soluble magnesium fertiliser, to combat the Orange
Frond symptoms. When the palms failed to improve, PNGOPRA approached the
Australian Centre for
International Agricultural Research (ACIAR) and CSIRO researchers
in Townsville to help tackle the problem.
According to CSIRO plant scientist Dr Michael Webb, ‘Soil research
into the volcanic ash soils of PNG indicated that there are high levels
of calcium in West New Britain, while in Oro Province the soil’s
ability to hold onto magnesium is very low. Although the situation in
each place is different, the end result is the same – highly soluble
magnesium fertiliser might be washing away before the plant can capture
it.’
‘However,’ Dr Webb explains, ‘there is limited information
on movement of water or magnesium through these soils and we cannot predict
the fate of added fertilisers. Consequently, information on soil hydraulic
properties is essential if we want to understand leaching pathways.’
As part of a five-year ACIAR funded project, Dr Webb is working closely
with PNGOPRA scientist Dr Paul Nelson and colleagues in PNG to determine
why magnesium deficiency is causing the problem when magnesium is routinely
added.
 All
the evidence points to magnesium deficiency being the causal effect of
the symptoms even though there has been little response to magnesium fertiliser.
Their evidence is based on plant sample analyses and soil chemical and
physical properties that are unique to this region.
‘Our role is now to determine how we can supply magnesium in a
much more effective way’, Dr Webb says. ‘We are testing some
less soluble forms such as magnesium carbonate in an attempt to keep the
magnesium close to the palm roots for longer.’
‘CSIRO’s Davies
Laboratory in Townsville is also playing an important role in this
research. Tools developed there for studying soils are very suitable for
this project, plus we have ready access to scientists with expertise in
tropical soils and plants, analytical facilities and a glasshouse.’
As well as looking into techniques to prevent magnesium fertiliser from
leaching away, research will take a longer term, strategic approach in
the search for more effective, alternative ways of supplying magnesium
to palms.
The team will look at the extent of the problem and the usefulness of
diagnostic factors and they will examine the properties of the soils,
palms and fertilisers affecting magnesium nutrition. At the same time,
the research team will develop a program to predict when and where magnesium
deficiencies might occur and how best to manage the problem.
Some PNG researchers have come to Australia for training in HYDRUS software
to predict magnesium movement through the soil. Dr Webb travelled to PNG
to collaborate with Dr Nelson in designing experiments and sampling soils
and oil palm leaves. ACIAR also asked Dr Webb to look at magnesium nutrition
of local food crops such as taro, yams, sugar cane and bananas.
‘By working closely with PNG researchers and producers’,
says Dr Webb, ’we are able to combine our expertise with theirs,
leading to effective solutions to plant nutrition problems that have a
substantial impact on rural productivity and incomes.’
CSIRO contact:
Dr Michael Webb
Ph: +61-7-4753 8500
| Per hectare, oil palm is the
highest yielding vegetable oil crop in the world. Producing saturated
and unsaturated oils, its applications include cooking oil, margarine,
soap and cosmetics as well as various industrial uses.
Oil palms grow up to 14 metres high, and produce fruit
continuously. Originally from the wetter parts of West Africa, the
oil palm is essentially a low altitude (below 400m) wet tropics
crop.
Oil palms were introduced to PNG in 1895 and commercial
plantings were established in 1967. The industry is crucial in socio-economic
terms as it provides family incomes for smallholder growers, and
is a source of independent income for local women who have been
encouraged to collect loose fruit under the ‘Lus Frut Mama’
scheme.
According to Sir Michael Somare, PNG’s prime
minister, the oil palm industry is ‘Creating direct employment
for over 20,000 people and over 150,000 in indirect employment opportunities
across the country’. |
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