Indonesian Experiences: Effects on Soil and Water Biodiversity of Shifting from Conventional to Organic Farming in Paddy Fields

Most rice field ecosystems in Indonesia are managed using either conventional or organic methods, or a combination of the two. Conventional management involves applying agrochemicals such as inorganic fertilizers and chemical pesticides. Recently, however, the government is socializing organic or semi-organic management methods among farmers' groups. Any resulting change from conventional to organic farming systems is likely to affect biotic environments in rice paddy fields. Although changes in biodiversity are due to the different inputs for conventional farming as opposed to organic, the extent to which inputs affect biodiversity needs to be clarified.

We conducted research during 2006–2007 in the Pagelaran subdistrict of the Tanggamus district in Lampung Province. The research studied how the physical, chemical, and biological properties of soil altered as a result of the farmers changing their rice paddy fields from conventional to organic cultivation. In the following description, however, we will focus only on changes affecting soil and water biodiversity in the paddy fields.

The farmers had cultivated rice in the paddy fields since the 1970s and had used high inputs of agrochemicals, high quality seeds, etc., to generate higher rice production volumes. From the year 2000, however, some farmers who were members of Ikatan Petani Pengendali Hama Terpadu (IPPHT, the Farmers' Association for Integrated Pest Management) realized that although they were using high inputs the rice yields were not increasing anymore and the soil fertility had deteriorated. The soil was hard, and cracking, and lacking in fertility due to reduced levels of organic matter. From then on, therefore, certain farmers pioneered the use of an organic fertilizer called “bokashi.” Bokashi was introduced by Japanese farmers; it is a compost made from paddy husk, cow manure, and microorganisms that act as decomposers. Recently it has become very popular in Indonesia too. The farmers make their own bokashi using microorganisms produced using local materials (i.e., papaya fruits are mixed with coconut water and palm sugar, then fermented for 2 weeks, and the supernatant which contains microbes is used as decomposer).

The Pagelaran farmers refer to themselves as organic paddy farmers and they cultivate rice in paddy fields twice a year (there are two seasonal planting periods, in the wet and dry seasons). During each planting period they apply about 4 t bokashi ha−1 and they do not use chemical fertilizers anymore. They also no longer use chemical pesticides, which they replaced with organic pesticides made from local plants such as tobacco and ginger.

Our study commenced in 2006, and we surveyed farmers who converted to organic methods during the period from 2000 to 2005, since each farmer converted at a different time. Within the sample, therefore, farmers who started organic farming in 2005 had one year's application of bokashi, those who started in 2004 had 2 years of application, and so on. Farmers who had not applied bokashi by 2006 (non-organic farmers) were used as a control (0 years' application). Some farmers did not want to be organic farmers because they were afraid their rice production would be low if they did not use agrochemicals as fertilizers and pesticides. The results of the study are reviewed below.

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