ASIATODAY.ID, BALI – Farmers in Bali have long implemented innovations related to water purification technology using plants. The innovation is framed in a local wisdom called andongan. The application of andongan has been adopted for centuries by Subak farmers to obtain better water quality from Subak irrigation streams. Subak residents are highly dependent on the availability of clean water for agriculture. Andongan is a simple yet effective solution to fulfill the need for clean water. Besides its function as a water purifier, andongan also has a deep cultural meaning for the Subak community.
Some literature mentions that Subak existed in Bali since the early ninth century. For many years, Subak has successfully managed and utilized water sources for irrigation. Subak members maintain the irrigation system, ensure equitable water distribution to farms, mobilize resources and help each other, resolve conflicts, and provide the performance of rituals. The Balinese are the most productive rice farmers in Indonesia thanks to the Subak system, which also ensures a high level of food sovereignty for the population.
Subak was recognized by UNESCO as a World Cultural Heritage in 2012. The future stability of the system and the existence of Subak is seen as very important. However, Subak conservation efforts face several challenges, one of which is the reduction in the size of the Subak area and the decline in the quality and amount of water resources. There are additional issues, such as the lack of clear external regulations in favor of Subak conservation and the age of farmers above 40 years. The complexity and its relationship with new agricultural practices and the increase in tourism on the island places the Subak system in a fragile position. The reduction of paddy fields is largely due to the growth of tourism activities.
Subak is a local organization that uses traditional Balinese ecological knowledge and wisdom to regulate and provide water for agriculture. Subak is not only responsible for organizing the distribution and sharing of irrigation water, but they are also responsible for setting the planting schedule and cropping style each year. Over the years, Balinese people have maintained water resources and managed water quality using various local wisdom. Local wisdom is passed down from generation to generation through daily activities. Purification of irrigation water using andongan, local wisdom, is one of the water quality management strategies that has long been applied by farmers who are members of Subak. Farmers still use the andongan concept today, including in Subak Sembung, Denpasar-Bali.
More attention is needed to understand and predict the long-term impacts of rapid changes in irrigation water quality. Today, the quality of irrigation water used is critical to the sustainability of agriculture. The quality of irrigation water from surface water sources varies widely. This is especially true for waters that are often contaminated, such as rainwater runoff or livestock feces that enter rivers directly. The risk of contamination of food crops increases when irrigation systems are polluted, which means the application of the best monitoring methods is necessary.
The removal of toxic organic and inorganic pollutants from water is essential to create a clean environment, both for human society and as a response to water scarcity. Water pollution contributes to the decline in drinking water availability worldwide and is one of the major risk factors for illness, disease, and death. Indigenous peoples’ local wisdom on nature conservation is essential to protect the biodiversity of indigenous peoples and their lands.
Water purification efforts through andongan are not new to Subak member farmers in Bali, especially in Subak Sembung, Denpasar. Andongan is still used today due to its sustainable implementation. This condition is in line with the basic idea that local wisdom is passed down from generation to generation and is not affected by various elements of ignorance from the outside. Local wisdom can be defined as concepts, views, or values embraced by a community in a place. However, modernization and globalization pose a threat to the development and maintenance of local wisdom.
Farmers teach the function and role of andongan to their children or the next generation practically. Learning is done through practice rather than theory, given that local wisdom is a system of knowledge gained from past experiences and adopted and passed on through an evolutionary process to the next generation. Local knowledge will only survive if it is concretely applied in daily life. Education not only teaches ideas but also builds perspectives and personalities that help maintain local culture.
Andongan is one example of Balinese wisdom on water management. Water is considered a source of life as it enables food income as well as the sustainable development of the agricultural sector. According to some literature, Balinese respect water as it is a part of nature that must be preserved. Andongan is not only a Balinese cultural heritage but also a sustainable way to preserve water. The system is easy to maintain and environmentally friendly. The source of inspiration for the development of efficient and sustainable water management technology is Andongan. In traditional literature, water is explicitly mentioned as one of the important aspects of Balinese agricultural life.
Andongan is a shallow pond filled with aquatic plants that serve to improve water quality before it is used to irrigate rice fields. Farmers usually make andongan at the water inlet before the water is channeled to the rice fields. Andongan local wisdom is very similar to phytoremediation technology. Phytoremediation is defined as an economical, effective, and environmentally friendly technique to reduce heavy metal contamination. This method is cost-effective, highly effective, and environmentally friendly. Phytoremediation is a reasonable and profitable method to remove heavy metals from polluted areas because it uses hyper-accumulator plant species that are highly tolerant to heavy metals present in the soil or environment. This technique uses green plants to remove, decompose, or detoxify harmful metals.
There are various sizes of andongan ponds, depending on the area of land to be drained. On average, they have dimensions between one meter by two meters or two meters by six meters, and their depth averages 15 to 30 centimeters. But usually, the plant species used for each andongan is the same. Plant species are the main component that causes differences in removal efficiency in phytoremediation. The choice of an appropriate phytoremediation method for decontamination is influenced by soil properties, heavy metal levels and characteristics, plant species, and climatic conditions. Fletcher and friends in an article entitled “Phytoremediation Using Aquatic Plants” published in 2020 stated that Phytoremediation is a nature-based solution that has the potential to provide efficient, spatially adaptable, and multi-target treatment of polluted waters by using the ability of macrophytes to absorb, and degrade pollutants.
Water hyacinth (Eichornia Crassipes) and lotus (Nymphae sp.) are two plants used in andongan. The selection of these two types of plants is also related to the way they are used by farmers. When large and overgrown, water hyacinth can be harvested and used as feed for ducks and pigs. According to Rajan and colleagues in an article titled “Water Hyacinth a Sustainable Source of Feed, Manure and Industrial Products: A Review” published in Agricultural Reviews in 2022, the use of water hyacinth as poultry feed improved cellular immunity and egg-laying ratio.
Farmers choose water hyacinth as an andongan plant based on the knowledge and experience they gained from their predecessors. Based on this knowledge and experience, they believe that water hyacinths can improve water quality. Its adaptability to various environmental conditions and high nutrient uptake means that water hyacinth can be widely used for phytoremediation purposes. The use of water lilies as part of andongan was obtained by farmers from hereditary knowledge. Based on experiments from Noerhayati and friends written in an article entitled “Improving Wastewater Quality System Using The Internet of Things-Based Phytoremediation Method” published in the Journal of Ecological Engineering in 2023 found that lotus was able to provide a 32.91% reduction in COD, a 31.54% reduction in BOD levels, a 3.55% reduction in phosphate levels and a 19.61% reduction in nitrates.
Andongan, a long-used phytoremediation technique, can be an alternative strategy for cleaning up polluted soil and water. However, its sustainable implementation still faces some challenges. There is a tendency for tenant farmers to be reluctant to build andongan, as it will reduce their cultivated land, which in turn will affect crop production or yields. Another challenge in conserving andongan is the limited number of farmers who farm in an integrated manner while raising ducks, cows, and pigs. As a result, farmers no longer cultivate water hyacinths to be used as animal feed. Another problem is that young farmers still lack knowledge about andongan and its benefits in environmental remediation. Limited information about andongan has led to a reluctance to implement it. (***)
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