The Philippine Rice Research Institute (PhilRice) is urging farmers to refrain from burning rice straws, saying this could reduce soil nutrients and make farmlands unproductive.
Evelyn Javier, supervising science research specialist of PhilRice’s Agronomy, Soil and Physiology division, said rice straw-burning, which is being practiced during the harvest season, causes air pollution by producing carbon dioxide, carbon monoxide, nitrogen dioxide and sulphur dioxide.
When done frequently, she said rice straw-burning could reduce the soil’s nitrogen and phosphorus content by 25 percent.
“It also cuts potassium content in soil by 20 percent and sulphur by 5-60 percent,” she said.
Javier added that some beneficial insects are killed when rice straws are burned.
“Useful insects kill some other harmful insects which destroy palay and make production less,” she said.
PhilRice said Republic Act 9003, the Solid Waste Management Act of 2000; and Republic Act 8749, the Clean Air Act of 1999; both prohibit open-field burning, including burning of rice straws.
Based on PhilRice statistics, the country produces 15.2 million tons of rice annually, of which 11.3 million 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.
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, these maintain soil 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,” she said.
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 also recommended the use of rice straws as substrate for oyster mushroom production.
Instead of burning rice straws, Corales said the same could be utilized for other agricultural purposes.
“Using rice straw as mushroom substrate is economically profitable for farmers and people engaged in agribusiness,” he said, adding that waste from mushroom production is also the main substrate for vermicomposting, one of the best organic fertilizers produced.
Likewise, the Philippine Carabao Center (PCC) said that using rice straw as fodder is good for buffalo and cattle production.
“Although rice straws have low protein content (4-4.5 percent), it can be sprayed or treated with molasses and urea to increase its nutritive value and feeding quality. The urea-treated rice straws’ protein content ranges from seven to nine percent. When fed to dairy buffaloes, the feed intake is increased by 12 percent, milk production is improved by 18% and it increases the farmer’s profitability by 33 percent,” a PCC study showed. (Marilyn Galang/PNA)
