14 January 2009 | EN
A palm oil plantation in South-East Asia
[JAKARTA] Scientists in Indonesia have developed a treatment to improve the productivity of the country's swathes of peat forest, which have been cleared for agriculture but are difficult to farm.
Peat soil is difficult to cultivate due to its high acidity, which results in fewer nutrients available to plants. Shallow peat — less than one metre deep — is used for tidal rice fields, dry land crops such as maize and cassava, and a variety of fruits and vegetables. All require a neutral pH of around 5 or 6.
But conventional ways of increasing pH, such as adding ash or limestone to the soil, are unsuitable for large-scale use because of their limited availability.
Scientists from Indonesia's Agency for the Assessment and Application of Technology (BPPT) have been developing a mixture of microbes found in liquid waste from the palm oil industry and the empty bunches of oil palm fruit — an abundant waste material high in cellulose — as a carbon source for the microbes.
Their latest research was conducted in unused peatlands in Pontianak, West Kalimantan Province, which had an initial pH 3.5–3.6.
Researchers combined the mixture with the top 10–15 centimetres of peat. They found this improved soil fertility, with farmers in the area showing that peat soil of less than three metres could be used to grow vegetables. Other trials showed maize grew faster on treated rather than untreated areas.
Scientists believe acids in the peat may be converted as the microbes degrade the cellulose in the fruit bunches.
Indonesia has around 70 per cent of the total 16 million hectares of peatland in South-East Asia.
Chalid Muhammad, former executive director of WALHI — an Indonesian environmental nongovernmental organisation — said using the mixture should not become national policy, as peat forests should not be cleared for agriculture in the first place because of their importance as carbon stores and a source of income for local communities.
Janet Cotter, a soil scientist at the UK-based Greenpeace International Science Unit, doubts that the method could be applied on a large scale.
"Peat soils are not suitable for agriculture. This merely demonstrates the foolishness and futility of deforesting peatlands for agriculture."
The research was discussed at the ASEAN-China Workshop on Development of Effective Microbial Consortium Potent in Peat Modification, held in Jakarta, Indonesia, last year (11–15 November).
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