Spotlight: Michael A. Bengwayan

Rapid Composting, A Faster Way To Cash and Safe Vegetables

An article by Michael A. Bengwayan

Baguio City, Philippines: In many less-developed countries, many farmers are using compost to cut down costs on fertilizers. But composting normally takes three to four months, a long time especially for  marginal and hand to mouth subsistence  farmers.

There is a way to compost in only a month’s time. Yes, one month. By using Trichoderma harzianum Rifai.

Trichoderma is a  cellulose decomposer fungus isolated from a soil in Mount Makling, Philippines by Dr. Virginia C. Cuevas of the University of the Philippines.  Because of  Trichoderma,  many Filipino farmers are now composting faster. This technology can be used by other poor farmers in the world as well.

The fungus is cultured in sterile sawdust mixed with leaves of ipil-ipil (Leucaena leucocephala, a leguminous tree). The whole package — a one-kilogram pack of fungus medium in a plastic bag — is referred to as compost fungus activator (CFA). The activator is broadcast over rice straw or other plant residues when the substrate is made into a pile. It should be applied at a rate of 1% (by fresh weight) of the substrate. Adequate moisture and aeration should be provided throughout the composting period.

The activator increases the population of microbial cellulose decomposers. If the compost pile has an adequate moisture content, enough nitrogenous materials and good aeration, these microorganisms multiply rapidly. The increase in the population of microorganisms raises the temperature inside the compost heap, which in turn hastens the decomposition process. The composting period is shortened to just four weeks

The experiences of farmers  being assisted by  project PINE TREE and the Igorot Tribal Assistance Group in the Cordillera Region, Philippines, regarding composting with Trichoderma have led to many farmers earning more and harvesting safer vegetables.

They have done so by producing compost which they use and partly sell sell to other farmers during agricultural trade fairs. Their Trichoderma-assisted compost are being used to grow organic vegetables like cabbages, potato and carrots;  spices  like  raise mint, parsely, spring onions, thyme, garlic, hot chili  and cut flowers like anthurium and chrysanthemums.

The farmers’ produce are certified by the Department of Agrculture as organic thus, they sell their crops ate a higher price and certainly, more and more customers buy from them because they also don’t use pesticides.

Here is how the Trichoderma compost is prepared.

Steps In Composting With Trichoderma

Preparation of Substrates
Substrates such as rice straw, weeds and grasses should be chopped. Chopping helps speed up decomposition by increasing the surface area available for microbial action, and providing better aeration. If large quantities of substrates are to be used (i.e. several tons), a forage cutter/chopper is needed. Chopping can be dispensed with if the compost is not needed in the near future.

Substrates should be moistened with water. Plant substrates can be soaked overnight in a pond, which cuts down on the need for water. If a large volume of substrates are to be composted, a sprinkler is more convenient.

The Compost Mixture
Carbonaceous substrates should be mixed with nitrogenous ones at a ratio of 4:1 or less, but never lower than 1:1 (on a dry weight basis). Some possible combinations are:

• 3 parts rice straw - 1 part ipil-ipil  (any nitrogen fixing legume or tree foliage or leaves will do)
• 4 parts rice straw - 1 part chicken manure or hog or cow manure
• 4 parts grasses - 1 part legume materials + 1 part manure
• 4 parts grasses - 1 part Chromolaena odorata or Mikania cordata + 1 part animal manure

Note: Chromolaena odorata is a common broad-leaf weed. Mikania cordata is an herbaceous climbing plant, a common weed in the Philippines.

It is important to use grasses and weeds which do not have any flowers or seeds.

Composting Procedure
The substrates should be piled loosely in a compost pen to provide better aeration within the heap. The material should not be too compact and no heavy weights should be put on top. Compost heaps should be located in shady areas such as under big trees. The platform should be raised about 30 cm from the ground, to provide adequate aeration at the bottom. Alternatively, aeration can be provided by placing perforated bamboo trunks horizontally and vertically at regular intervals, to carry air through the compost heap.

The compost activator, consisting of a cellulolytic fungus, is broadcast onto the substrates during piling. The amount of activator used is usually 1% of the total weight of the substrates (i.e. about 1 kg compost activator per 100 kg substrate). Decomposition is faster if the activator is mixed thoroughly with the substrate. A greater amount of activator can be used if faster decomposition is desired.

The heap should be covered over completely. This maintains the heat of decomposition, and minimizes water evaporation and ammonia volatilization. White plastic sheets, or plastic sacks with their seams opened and sewn together, can serve as a cover.

The compost heap usually heats up in 24 - 48 hours. This heat is very important, especially if manure is used, because it kills disease microorganisms. Some seeds of weeds are also rendered nonviable. Temperature readings should be taken at different parts of the pile at least three times a week.

Heat should be maintained at 50°C or higher, and the heap should be turned over every 5-7 days for the first two weeks, and thereafter once every two weeks. Turning over the pile provides adequate aeration, and evens up the rate of decomposition throughout the pile. It also serves as a means of checking the moisture content of the substrate. After the first week, the volume of the pile should be reduced by one-third. After two weeks, the volume of the pile should be reduced to one half the original.

Compost Maturity
The compost is ripe if:

• The temperature in all parts of the pile drops to 33-35°C, or approximately air temperature, after the 2nd or 3rd turning.
• The different materials in the substrate are no longer recognizable.
• The compost is dark brown to black, and looks like soil.
• The ripe compost does not emit a foul odor.

If the temperature of the heap drops to 30°C but the compost is not needed immediately, it is best to let decomposition continue further. The mature compost should be removed from the pen, and dried in the sun for two days. It should then be put into sacks and stored in a shaded area. Decomposition will continue until the substrate is finely fragmented, so that the finished product has a powdery texture. Then, once decomposition is complete, the compost should be sun-dried again until the moisture contest is at most 10-20%. /Michael A. Bengwayan

If mature compost is needed at once, it should be sun-dried for one day, as soon as its temperature drops to 30°C. Drying removes excess moisture, and makes the compost much easier to handle. Although the compost still retain some fibers, it can be applied immediately as fertilizer.

In a tropical country like the Philippines, compost can be made throughout the whole year. Mature compost can be stored for at least six months without any appreciable change in nutrient content, especially if the stored compost has a very low moisture content (10-20%).