Rapid Rice Straw Composting
Ordinary composting, which requires three months for complete
decomposition, is too slow for farmers who plant two or three
rice crops a year. The IBS rapid composting method (named after
the Institute of Biological Sciences at the University of the
Philippines, Los Baños), speeds up the process with a compost
fungus activator, Trichoderma harzianum. The activator complements
soil microbes as a source of waste cellulose decomposers, thereby
increasing the number of decomposers and the rate of decomposition
so that farmers can use the compost sooner.
Rapid composting requires carbon-rich materials such as rice straw,
nitrogen-rich materials like animal manure and the activator Trichoderma
harzianum. A combination of three parts carbon to one part nitrogen
substrate is best. If animal manure is difficult to obtain, it
may be replaced with leguminous plants such as azolla and sesbania.
Trichoderma harzianum, is widely produced in the Philippines by
the Departments of Science and Technology and Agriculture, state
universities, non-government organizations and farmers' cooperatives.
- At harvest time, rice straw is heaped to one side of the paddy.
It saves labor later to have one compost pile for each paddy instead
of one central pile.
- Rice straw is soaked overnight in irrigation water or in the
rain until saturated.
- A simple platform is made in the middle of the paddy (size
is relative to the size of the paddy).
- A layer of saturated rice straw 10-15 cm thick is loosely
piled on the platform.
- On top of the layer, one or two handfuls of the activator
is broadcast (25 kg /ha).
- Straw is alternately layered with the activator until all
the straw has been used.
- Manure and nitrogenous plants are put on top of the straw
layers. The nitrogen substrate is 15-25% of total composition.
- The compost is covered (with plastic, banana leaves, or coconut
fronds) and heats up within 25 hours.
- The compost must be moistened frequently to compensate for
- The compost is left unturned and matures within one month.
It is ready for use when the pile has cooled and is 30% of its
Income gains resulting from a healthy crop are the most immediate
return. But more importantly, the soil benefits from continued
use of compost in the long term. Results include improved soil
texture and tilth, better aeration and water-holding capacity,
increased fertility and less acidity. Because rice straw is composted
and not burnt, less carbon dioxide is released into the atmosphere.
Compost reduces the need for chemical fertilizers which contaminate
surrounding waters and encourage algae blooms that compete with
fish for oxygen. Additionally, as farmers gain self-reliance they
become less dependent on off-farm inputs.
Rapid composting, like composting in general, often means more
work for the farmer. Labor inputs can be reduced by composting
in the paddy and in small heaps that are easily transportable.
A reliable supply of T. harzianum is critical to facilitate the
rapid decompostion process. Contaminants reduce the effectiveness
of the activator and may cause skin irritations. Also, limited
manure supply may result in compost with low N content.
Rapid composting turns a problem into a solution by using formerly
wasted rice straw to benefit the soil. The process fits into farmers'
busy planting schedules and can help to make them more independent
of chemical inputs purchased externally.
Virginia Cuevas. 1993. Rapid Composting Fits Rice Farmers.
ILEIA. 9 (2), pp. 11-12.
University of the Philippines at Los Banos
Laguna, PHILIPPINES 4031