Adaptability of the Technology
This techology is best suited to small-scale farming, and to sandy, acidic and relatively infertile soils. It is effective for such crops as soybean, cowpea, corn and sorghum. It is also worth trying for other field crops and vegetables.
How to Prepare the Charcoal
Prepare the rice husk charcoal as follows.
- 1) Puncture small ventilation holes in a tin can (about 18-liter capacity) and insert a metal pipe for a chimney ( Fig. 1(79)).
- 2) Put several sheets of screwed-up newspaper inside the can.
- 3) Set fire to the newspaper.
- 4) Cover the can quickly with dry rice husk ( Fig. 2(79)).
- 5) Wait for 6-8 hours.
- 6) When the surface of the heap is smoked black, remove the can from the pile of rice husk and put out the fire with water.
How to Use the Charcoal
Apply the rice husk charcoal to the field at an application rate of 10-20 mt/ha. Row application is recommended, rather than broadcasting. After application, the rice husk charcoal should be mixed into the surface soil for best results.
Effects of Charcoal Appplications
Application of rice husk charcoal at the recommended rate will give a yield increase of 10 - 40% ( Fig. 3(73)). The rate of the increase depends on the crop, the nature of the soil, and the application rate of chemical fertilizers which supply other nutrients ( Table 1(74), Table 2(73), Table 3(81)).
Reasons for the Effectiveness of Rice Husk Charcoal
The mechanism whereby rice husk charcoal improves crop yield is not clearly understood. The effect may vary from soil to soil. However, the following effects have been seen in experiments.
- 1. The rice husk charcoal increases the soil pH, thereby increasing the available P.
- 2. The aeration in the crop root zone is improved.
- 3. The water-holding capacity of the soil is improved.
- 4. There is an increase in the level of exchangeable K and Mg.
- 1. The rice husk must not be burnt so throughly that it turns to gray ash.
- 2. Agricultural technologies are highly location specific. Please try this new technology first on a small scale, to see if it works in your own field.
Index of Images
Figure 1 Tin Can with Ventilation Holes and Chimney
Table 2 Field Trial for Soybean in Indonesia
Figure 2 Making Charcoal
Table 1 Field Trial for Soybean in Thailand
Figure 3 Better Growth of Corn with the Application of Rice Husk Charcoal
Table 3 Soil Properties after Harvest of Preceeding Crop
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