Following on from yesterday's story about AWD (Alternate wetting and drying farming), AWD can contribute to climate change mitigation measures by reducing methane gas production by about half and can reduce water use by about a third. How exactly this is done is simply by preparing a 40 cm PVC pipe. Just a pipe with a diameter of about 4 inches, which we use for our biogas, is ideal because it allows us to see what is going on inside. But this 4-inch pipe is actually a bottleneck. These days, not so much, but toilet plumbing is often made with pipes as small as 2 inches in Indonesia. So there may be areas where 4-inch PVC pipes are not available. If you have a farmer interested in this AWD when you introduce our biogas, you may want to consider sending him some PVC pipe and it.
You can find out more about how this is done on YouTube at the International Rice Research Institute. To recap, you drill numerous holes in the bottom half of the pipe and insert the pipe halfway into the paddy. The mud in the pipe is removed so that we can see the water content in the pipe. If there is water up to about 15cm below the surface, the rice is fine. The rice plant roots are deeper, and, as mentioned previously, rice is a flood-tolerant plant and does not need to live in a constant flood area like water plants.
Depending on the water level and the area, it is possible to leave intervals of up to 5 days when the surface is dry. By using this pipe, you can also check the water level at the same time. To reapply water to the paddy, just apply 5 cm of water above the surface. If the AWD fails to reduce weeds, which is one of AWD objectives, it is best to leave the field as a flood until the weeds eliminated.
AWD will also make the paddy fields more suitable for producing other vegetables, and if the dry season continues, it will be easier to produce crops other than rice.
As Indonesia's report to the United Nations shows, Bali is the most likely place in the country to experience water shortages. In addition to agriculture, there is another water-intensive industry, tourism, which is also in competition with Bali. In addition to reducing competition for water, there is another reason why AWD is useful in Bali, where there are many hotels. In my area of Canggu, which is highly urbanised, there are often paddy fields between buildings. When there is a gust of wind, the same phenomenon occurs in urban buildings, and we often see rice being torn down. I have not studied this statistically, so I am not sure, but if there is a greater chance of a rice crop being knocked down by a building wind caused by a hotel, etc., it will be more resistant to gusts if the roots of the rice are more deeply embedded in the ground. The AWD is not always waterlogged, so the roots go deeper in search of moisture. As a result, the paddy fields will be more resistant to building winds. This is a very beneficial story for Bali, where tourism and paddy fields are mixed.
The first Climate Field School I started with BMKG was for rice farming. In LANDMARC, which we are doing now, the project has Nepal's case, decarbonisation from rice farming. I may go around and get involved in rice research in Bali again ;-)