Rice straw can be used to make geo-textiles, a class of products that is in great demand worldwide and whose market can reach $8.632 billion by 2019 according to marketsandmarkets.com.
Geotextiles are commonly used for applications such as erosion control on slopes and along roadways.
The most popular raw material for geotextiles is coconut husks, which are waste products from coconut farms and processing plants. Although the Philippines is a major supplier of coco coir geotextiles, India and Sri Lanka are the world’s top producers.
According to the paper “Utilization of Rice Straw Biomass in the Production of Biodegradable Geotextile” authored by Rolando Javellonar and Victorino Taylan, the country produces about 18.52 billion kilograms of rice straw annually.
“Of this amount, about 95 percent or 17.1 billion kg is left and burned in the field which emits greenhouse gases that contribute to global warming and climate change,” they added.
Javellonar is a faculty of College of Engineering and Technology, Romblon State University in Odiongan, Romblon while Taylan is faculty of the College of Engineering, Central Luzon State University in Munoz, Nueva Ecija.
The researchers prepared rice straw mat using a binder while rice straw net was prepared by making a straw twine that was turned into a rope by spinning two twines. Then from the rice straw rope a net was formed through weaving.
Javellonar and Victorino said their research showed rice straw mat had higher water absorption capacity at 328.5 percent and percentage swelling of 17.5 percent compared to rice straw net with only 167.3 percent and 1.8 percent, respectively.
However, their testing showed rice straw net recorded higher tensile strength of 2.0 kN cm-2 when wet and 1.95 kN cm-2 when dry as compared to rice straw mat with 1.08 kN cm-2 when wet and 1.02 kN cm-2 when dry.
“The observed water absorption capacity of rice straw mat and rice straw net as well as tensile strength of rice straw net exceeded the standard generic specification values set by the Department of Public Works and Highways for geotextile as erosion control material.
Hence, both the developed rice straw geotextiles can be utilized as ground cover for soil erosion mitigation or an alternate erosion control material in areas where coco coir net is not available,” the researchers said.
The paper of Javellonar and Taylan was presented during the annual convention of the Philippine Society of Agricultural Engineers on April 24-30 at the Mariano Marcos state University in Batac City, Ilocos Norte.