Soils of Java
Posted by dedenia72 on September 5, 2009
Not all of parts of Java are of course fertile, but compared to other areas in Indonesia, Java is extraordinary. Its fertility is mainly attributed to the presence of good parent materials from volcanic activities that had been spread over the Pleistocene period. Occasionally recent volcanic activities rejuvenate the parent material by spreading out new volcanic products in the neighboring areas. Volcanic materials are the sources of most major nutrients needed by crops. For example, volcanic ash spread by Mt. Galunggung of Tasikmalaya, West Java, in the 1982-1983 eruptions contain high amounts of basic element, like Calcium, Magnesium, and Phosphorus. Volcanic ashes ejected by Mt. Merapi, Central Java, contain phosphorus at even higher concentrations. When incorporated into the soil, and weathers ash materials may free the elements that are readily absorbed by plant roots. The spread of volcanic materials, especially the finest volcanic ash is very wide. Some reports mention that the radius of spreading may reach distance of hundreds of kilometers from the center of eruptions. This could maintain fertility of soils in the vicinity of the mountain. Since there are a lot of active volcanic in Java, the fertility of Java soils are maintained throughout the Java history.
In addition to regular rejuvenilization of soil parent-materials by volcanic ash, soils in the rice field areas of Java are in general well-managed. In the upland are terrace systems an rice field management in general have preserved soil fertility by minimizing erosion by water run off. However, in many upland areas, one to less or poor conservation practices, erosion are also common phenomena.