SCIENCE CITY OF MUÑOZ, Nueva Ecija—The Philipine Rice Research Institute has cautioned Filipino farmers to refrain from burning “dayami” (rice straw), saying this could reduce nutrients in soil and make farmlands less productive.
Evelyn Javier, supervising science research specialist of the PhilRice’s agronomy, soil and physiology division, said rice straw-burning, which is practiced during the harvest season, causes air pollutants such as carbon dioxide, carbon monoxide, nitrogen dioxide and sulphur dioxide.
When done frequently, she said this could reduce the soil’s nitrogen content and phosphorus content by 25 percent. It also cuts potassium content in soil by 20 percent and sulphur by 5 percent to 60 percent.
Javier said this practice also damages food resources of beneficial insects in the rice field.
The institute said Republic Act 9003, also known as the Solid Waste Management Act (RA 9003) and the Philippine Clean Air Act of 1999 both prohibit open-field burning, including burning of rice straws.
According to PhilRice statistics, the country produces 15.2 million tons of rice annually of which 11.3 millions are turned into rice straw.
To minimize post-harvest waste, rice straws can be used by farmers as organic fertilizer and primary material for mushroom production. Also, rice straw and other biomass from farm by-products can help farmers save expenses from chemical fertilizer inputs.
Javier said when rice straws are scattered in the field during land preparation, they maintain the soil’s nutrients such as nitrogen, phosphorus, potassium, sulphur, silicon and carbon as well as moisture.
They also preserve the biodiversity of microorganisms that helps in nutrient cycling and efficient fertilizer utilization.
Rice straws can also be used as mulch to protect the roots of the plants from heat and cold and reduce the evaporation rate and prevent weeds from growing in the paddy.
Rizal G. Corales of PhilRice’s Palayamanan Plus recommended the use of rice straws as substrate for oyster mushroom (Pleurotus spp.) production.
Corales said the bulk of the rice biomass produced is still being disposed indiscriminately despite its many known uses. “Using rice straw as mushroom substrate is economically profitable for farmers and people engaged in agribusiness,” he said, adding waste from mushroom production is also the main substrate for vermicomposting, one of the best organic fertilizers produced.
