Using Nature for Sustainable Rice Harvesting

A look at rice farmers in Bali and Dewi Sri, the Rice Goddess

Anthropologists are still arguing over the origin of rice, Oryza sativa, a staple grain most of us don’t pay too much attention to. Some believe its origins lie in China along the Yangtze River basin and spread throughout Asia. Still others believe it originated in India.

Wherever it originated, rice is part of just about everyone’s diet. Rice production is a big business in many countries. All together more than 787 million metric tonnes of rice was produced in 2021 (up from 216 metric tonnes in 1961).

In this article, we will look at rice farmers in Bali, Indonesia and the practice of rice stalk burning. For context, Indonesia ranks #4 in rice production out of the 113 countries that produce rice (2021).

A long history of rice farming

Wetland rice farming in Indonesia traces back to 500 BC. Indonesian rice farming is closely tied with Hinduism. Dewi Sri and other rice spirits and deities play an important part in Bali rice farmer’s rituals including when the rice is harvested. Harvesting takes place, on average, three times a year.

Once the rice is harvested, the fields are readied for the next planting. The straw that has been left behind during harvest is often burned in open field fires. While this is a quick method to remove the straw, weeds, and any pests, the results are terrible for the environment – so much so that straw burning is banned or strictly regulated in most agricultural regions. In Bali, where harvests occur more often, straw burning still occurs as a quick method to prepare for the next yield.

Straw Burning’s Negative Effects

The negative effects of straw burning are numerous:

• Loss of nutrients in the soil, depletion of soil organic matter, and a reduction of beneficial soil biota. This in turn leads to the use of chemicals to correct the loss which may have an adverse change in the rice’s nutritional value and the chemicals may be harmful to humans.
• Causes greenhouse gas emissions: CO2, nitrogen oxide, and sulphur dioxide.
• Produces aerosol particles (coarse particles from the ash) and fine particles both of which affect air quality and the radiation budget of the earth.

While ash in the soil has some silica retention benefit, the overall negative effects warrant discouraging straw burning.

Incorporating the straw into the soil has been found to be ineffective because the straw’s decomposition rate is too slow. In Bali, rice replanting takes place within 3 weeks of harvesting which is not enough time for the straw to have fully decomposed.

Nature’s Way To Use Rice Straw

If straw burning is bad for the field and the environment, and composting takes too long, what if instead we could put the straw to good use?

Through our Nature Works all organic, experimental farm, we are testing the use of microbes in rice straw as an alternative to rice straw burning. The results so far are promising: in addition to eliminating rice straw burning and its negative health and environmental effects, microbial composting has the added benefit of producing free fertilizer in the form of composted rice straw to low-income farmers.

Microbial Composting Results

In the Nature Works tests, we collected straw from 5 hectares of paddies, approximately 25 metric tonnes in volume. Rice straw is generally known to be about 40-50% carbon. Introducing microbes in the composting process reduced this down to as low as 15%.

If the same amount of rice straw was burned, it would have introduced 1,650 kg of CO2 into the atmosphere. Composting with microbes prevented approximately 41 metric tonnes of CO2 entering the atmosphere. Thus far, we’ve repeated this process three times although the amount of straw collected varied with the 25 metric tonnes being the largest.

Removing Pollutants in the Water

In our microbial composting work, we also found that composting water hyacinth helps to remove toxins from water. As an invasive plant species that grows really fast, this natural toxin remover when composted produces a rich fertilizer. This video shows all the testing measures we are using to reduce water pollution in rice paddies.

Preserving Cultural Rituals

Western technology has tried to change rice production in Bali before. In a region where rice planting and harvesting is still done by hand there is a strong belief in Dewi Sri as the benevolent “Goddess of Rice” and fertility. Upon her burial ground, it is believed that many plants grew, including padi, or rice. These cultural traditions cannot be ignored or changed. In fact, many rice paddies have shrines to Dewi Sri, and there are special blessings of the rice seeds before planting and for the workers to ward off bad luck and misfortune.

Dewi Sri is also revered in the Subak system, the irrigation that manages the water allocation for rice agriculture. All in all, she is associated with rice, fertility, a successful harvest, and family prosperity and harmony.

Any changes, such as no longer burning rice stalks, has to consider the cultural norms of the region. In this case, removing the straw for faster composting can ensure that the harvesting rituals under Dewi Sri are respected and preserved.

As you savor your next plate of fragrant Jasmine, Basmati, or any of the 120,000 rice varieties, take a moment to appreciate the delicate balance between tradition and sustainability that thrives in the rice fields of Bali, under the watchful gaze of Dewi Sri. Nature’s wisdom is guiding us toward a more harmonious and eco-friendly future for rice harvesting.

Learn more about how Laconic is working to deliver cleaner air through our decarbonization agricultural projects in Bali and watch this video.