Thursday, June 9, 2011

Accelerated Composting with Wild Sunflower

Abe V Rotor

Who would think those shrubs growing on roadsides and wastelands with bright yellow flowers make excellent compost?

Wild sunflower, Tithonia diversifolia, has been found to contain high nitrogen content, exceeding nearly 6 percent, and not only that, it contains enzymes that hasten decomposition and cut down composting time from three months to just a few weeks. This is why it is an excellent additive in composting rice hay and other farm wastes which have low N content and which normally decompose slowly.

Because of immediate heat buildup and sustained high temperature in the compost pile that the sunflower initiates, weed seeds and harmful microorganisms are sterilized. This cuts down bacteria and yeast responsible in fermentation which causes acidic reaction. Acidic soil locks up, nutrients that are otherwise available for plant use.

With the addition of chopped sunflower in the compost pile, the pH value remains at 7 to 8 (neutral to slightly alkaline), throughout the decomposition period. Under this condition nitrogenous materials are immediately mineralized into ammonium nitrogen (NH4N+) and nitrate (NO3) which are directly absorb by the plants.

These findings highlight the results of a graduate research at the University of Santo Tomas leading to a masteral degree in biological science. Says Luisito Evangelista, the researcher, "accelerated composting is the key to successful production of on-farm organic fertilizer especially in areas where sunflower abounds."

Wild sunflower is also an alternative to Trichodernia activated composting where the fungus inoculant is not readily available. This technology was developed by Dr. Virginia C. Cuevas of the Institute of Biological Sciences at UPLB in which Trichodernia, a cellulose-acting fungus is inoculated in the compost pile.

When the sunflower-activated compost was used on Red Creole onions, yield increased by as much as 20 percent, and the physical quality of the bulbs improved. Other than being bigger, the bulbs are brighter, heavier and more uniform in size. Their neck is well closed and this is important in storage as danger of rotting is reduced.

How can one make his own sunflower compost? Here is how.

1. A well drained area, half shaded if possible, is prepared. Here a compost pile of 2 x 4 meters in dimension, breast high when compact, will be constructed.

2. The raw compost materials are prepared by chopping the rice straw and fresh wild sunflower separately. The ratio by weight of sunflower to rice hay is 3:1. Chicken droppings or animal manure and top soil from the farm are also readied.

3. These materials are piled in the following arrangement: the rice hay makes the first layer, 20 cm thick. On top of it is the chopped sunflower, followed by manure and soil.

4. A second set of layers is made on top of the first, compacting the pile as the process is repeated. The pile should not be higher than 1.5 meters for convenience in watering and turning over.

5. Aeration tubes made of bamboo are planted vertically into the pile 50 cm apart. The tubes are made by partly opening the nodes, outside and inside to allow air to enter and heat to rise.

6. Temperature is monitored with a thermometer inserted through the tubes. Heat is expected to increase immediately reaching its peak for two weeks before it gradually declines.

7. Watering should be just sufficient to maintain a moisture content of 60 to 70 percent. Plastic or sacks are used to cover the pile to protect it from rain and to help conserve the heat generated.

8. As decomposition progresses the pile will shrink, and temperature will soon equal to that of the surroundings. After three to four weeks the compost is "ripe". To facilitate, the pile is turned once or twice before harvesting it.

9. Temperature is monitored with a thermometer inserted through the tubes. Heat is expected to increase immediately reaching its peak for two weeks before it gradually declines.

10. Watering should be just sufficient to maintain a moisture content of 60 to 70 percent. Plastic or sacks are used to cover the pile to protect it from rain and to help conserve the heat generated.

As decomposition progresses the pile will shrink, and temperature will soon equal to that of the surroundings. After three to four weeks the compost is "ripe". To facilitate, the pile is turned once or twice before harvesting it.

To know if the compost can now be used, here are the indicators.

• There is no foul odor emitted by the pile.
• Temperature has gone down to the same as that of the surrounding area.
• The original substrates are no longer recognizable.
• The color is dark, loamy and soft to touch.

Composting is a bio-oxidative process which results in the production of stable organic product that contributes directly to soil conditioning and fertility. In many books it is called mineralization, that is, the breaking down of organic compounds into their elemental forms and as they settle down in the compost or in the soil as may be the case, become available to plants. This is particularly true with nitrogen. This is nature's way of recycling chemical compounds, from organic to inorganic form, and vice versa.

Composting rice hay alone is not advisable as it has low C:N ratio. This is the reason farmers seldom convert rice hay - and also corn stover - into compost but would rather have other uses, such as roughage, if not burn them. The addition of sunflower, manure and topsoil brings the C:N closer (30:40) in order to increase the plant nutrient value of the compost while accelerating the rate of decomposition. Maintaining moisture content at 60 to 70 percent and temperature at 50 degrees centigrade in the initial two weeks, the pH levels stabilize between 6 to 8 which is favorable to both biological and chemical reactions taking place.

Start making your own compost with wild sunflower. You will find it highly advantageous over conventional methods. Composting is safe to health and the environment, and has many its socio-economic benefits.~

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