Rice serves as the essential sustenance for the Philippines, nourishing more than 115 million Filipinos and supporting countless smallholder farmers. But planting rice is never fun, so goes a line from a familiar folk song. Still, a lot of Filipino farmers continued to grow rice.
Statistics indicate that there are 2.9 million Filipinos involved in rice farming and related activities within the country. Rice cultivation occurs over approximately 4.8 million hectares, of which 3.28 million hectares are irrigated, while the remaining 1.51 million hectares consist of non-irrigated areas, including rainfed and upland regions, according to the Philippine Statistics Authority.
The Philippines is estimated to produce around 19 million tons of rice and there is generally considered to be about 0.7 to 1.4 tons of rice straw ("dayami") per ton of rice. Based on this data, it is estimated that about 20 million tons of rice straw is generated every year.
Unfortunately, Filipino farmers view rice straw as waste due to its minimal or nonexistent commercial value. As a result, farmers either burned them or just left them in the open field. "Burning of rice straws, generally practiced during the harvest season, causes air pollutants such as carbon dioxide, carbon monoxide, nitrogen oxide, and sulphur dioxide," said the Philippine Rice Research Institute (PhilRice).
The practice of burning waste straw in rice fields, therefore, is not environmentally sustainable. It also depletes the soil essential nutrients. According to PhilRice, burning reduces the soil's nitrogen content, diminishes phosphorus by 25%, potassium by 20%, and sulfur by 5-60%.
In addition, some beneficial insects –like ladybugs, dragonflies, and spiders – are most likely to be killed when rice straw is burned in the open field. "Useful insects kill some harmful insects which destroy palay," said Evelyn Javier, supervising science research specialist of PhilRice's Agronomy, Soil and Physiology division.
More importantly, burning rice straw is bad for your health. "Rice straw burning is also known to emit particulate matter and chemicals such as dioxins and furans that have negative impact on human health," said a policy brief paper published by the Economy and Environment Program for Southeast Asia (EEPSEA).
Rice farming comes with a steep climate cost. If rice straw is allowed to decompose in the fields, methane emissions are anticipated. Methane is a potent greenhouse gas, over 80 times more harmful than carbon dioxide over a 20-year period. Greenhouse gases are those present in the atmosphere that trap heat, leading to an increase in the surface temperature of celestial bodies, including Earth.
Approximately 8% of global agricultural greenhouse gas emissions are attributed to rice production. Methane emissions from floodplain paddy fields represent 12% of human-caused methane emissions, which contribute 1.5% to their warming effect.
"As the populations in rice-growing regions expand, the production of rice – and consequently methane – increases," cautioned Dr. Alan Teramura, a botany professor at the University of Maryland.
In the Philippines, for instance, the country's population rose by 3.69 million, increasing from 109.04 million in 2020 to 112.73 million. By the year 250, the anticipated population is projected to reach approximately 138.67 million, based on the most recent demographic forecasts.
Turning rice straw into something useful is very challenging. That's what Craig Jamieson, a British national who's originally trained in horticulture and has a master's degree in International Rural Development with "Distinction," is trying to do.
His work has taken him across Africa and Asia developing bioenergy solutions that enhance rather than compete with food production. In 2016, with support from the United Kingdom government, Craig established an industrial pilot plant making clean fuel from waste rice straw. Straw Innovations (SI) Ltd. was born.
He collaborated with the Laguna-based Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA) to create a pilot facility that produces clean fuel from rice straw.
The Rice Straw Bioenergy Hub (RSBH), as it is called, facilitates access to clean energy for remote and underserved rural communities. The energy derived from waste rice straw, offers an innovative suite of technological services for rice farmers.
"The RSBH stands as a testament to what we can achieve when science, innovation and community come together," Jamieson pointed out.
The clean fuel produced from RSBH is utilized for drying grains and subsequent milling. "We consulted with farmers, and they expressed a preference for using the energy for productive activities rather than for domestic purposes. Therefore, that is our focus," Jamieson clarified.
After harvesting, drying the palay is the next most crucial process. Upon harvesting, rice can contain as much as 25% moisture, according to IRRI. The objective of rice drying is to lower its moisture content to the recommended levels suitable for sale and long-term storage.
"It is important to dry rice grain as soon as possible after harvesting – ideally within 24 hours," IRRI explained. "Delays in drying, incomplete drying or ineffective drying will reduce grain quality and result in losses."
However, before drying can occur, rice must first be harvested. In this context, SI is introducing a rice harvesting system that has been developed over a span of five years. "The primary challenges involve removing the rice straw from the field and transporting it to a location where it can be utilized," Jamieson said.
The solution is the "5-in-1" harvesting technology, which refers to a machine that is claimed to be the first of its kind globally.
"Our machine operates in a single pass across the field and executes the five distinct operations involved in conventional straw collection – harvester, chopper, rake, densifier, and collection. It is more efficient and, importantly, it functions effectively even in wet conditions (muddy or flooded fields)," he emphasized.
The harvested palay is subsequently transported to a different machine where the grain is separated from the rice straw. "At the biogas hub, a dryer utilizes energy derived from rice waste to dry the rice grain, while another machine removes the husk, and yet another mills the grain, resulting in the final product," said Jamieson.
The drying process takes approximately 12 hours. "The innovative technology involves using rice straw to fuel the entire process," he explained. "We provide farmers with the opportunity to maintain ownership of their grains throughout the entire procedure."
In many current scenarios, farmers receive only 4% of the rice's purchase price. In the SI approach, farmers can take advantage of its harvesting, drying, and milling services, and subsequently sell the finished products to consumers. "We simply take our share after the sale," he said.
"In the past, the government tried to give out free rice dryers but as soon as something broke, the dryers were no longer used," Jamieson said. "Our business model is to work with and support the farmers to ensure long-term sustainability."
He asserted that effective management of rice straw in a sustainable manner must achieve a balance between energy production and soil restoration to preserve soil fertility and guarantee productive agricultural lands.
"Some of the bioenergy we are producing is, in fact, combined heat and biochar," he said. "The heat is used for drying rice, and the biochar is returned to the soil to build up carbon levels and increase fertility. We are encouraged by the early results of this approach as a solution for the food-energy-water-carbon nexus."
The Department of Agriculture (DA) Region IV-A recognized the initiative for its potential benefits to farmers and the economy. During the Techno-Demo at Pila, Laguna, the DA Regional Executive Director Fidel L. Libao was quoted as saying:
"Rice straw innovation can power a circular agricultural economy—a system where nothing is wasted and every byproduct adds value. When we treat straw as a resource, we create farming that delivers higher yields, cleaner air, stronger rural economies, and a healthier planet."
At the recent Techno-Demo, SI also showcased a full suite of sustainable rice farming technologies and innovations. These include:
Straw Traktor. This is a machine equipped with a soil amendment applicator and a land rotavator, leading to improved soil health, enhanced crop quality, and increased yields.
He said processed rice straw can be transformed into pellets or briquettes, biogas or biochar (a substance resembling charcoal), which are currently being employed by various companies.
Rice straw can also be used as bedding for livestock (particularly swine), organic compost or fertilizer thereby generating new income opportunities for farmers.
Mushroom cultivation. This process uses rice straw as substrate for mushroom production thus giving additional income for farmers.
Enhanced rock weathering. This advancement utilizes natural soil amendments to enhance fertility and facilitate carbon sequestration whilst replacing nutrients lost by removing straw.
Koolmill. A next generation rice mill that uses up to 90% less energy and reduces grain breakage, thus increasing profits.
The British innovator is confident that the rice straw bioenergy hub can eliminate the burning of millions of tons of rice straw waste throughout Asia, where the majority of rice is cultivated. "It can provide clean energy access for productive use, or other income opportunities to the 150 million small-scale rice farmers who produce the staple we depend upon," he said.
Jamieson hopes it can address climate challenges faced by developing countries like the Philippines. "As a biomass specialist, the potential of rice straw made me drool," he said. "All around the world, the hunt has been on for a large amount of biomass that can be used for delivering clean energy or circular economy benefits without competing with anything else. Rice straw is one of the largest biomass sources in the world and is still mostly underused or wasted."