Discipline: Environmental Science
About 32% of the Philippine land area is devoted for agriculture. Given this, the agriculture sector is expected to increasingly generate significant emissions of non-carbon dioxide (CO₂) greenhouse gases (GHG) and their precursors such as methane (CH₄), carbon monoxide (CO), nitrous oxide (N₂O) and nitrogen oxide (NOX) from open burning of biomass residues from rice, corn and sugarcane farming. This study was undertaken to generate an updated yet specific inventory of contributions of provinces and regions to the total emissions of such radiative gases. Biomass residues from rice, corn and sugarcane were purposively sampled from the field and subjected to laboratory analyses to determine carbon fraction as well as carbonnitrogen ratio values. Secondary data on annual crop production were obtained from the PSA while default values of emission factors were secured from the IPCC. Inventory of such non-CO₂ GHwG emissions covering all provinces of the Philippines were undertaken using the IPCC Tier 1 approach. Thematic maps were then generated through simple geographic information system. The study showed an average annual total emissions of 21 Gg, 550 Gg, 0.4 Gg and 15 Gg, respectively for CH₄, CO, N₂O and NOx from 1990 to 2015 with CO constituting 94% of the emissions. Western Visayas was the top “hotspot” region with about ⅓ of the total emissions. Other “hotspot” regions include Central Luzon, Northern Mindanao and Cagayan Valley. Apart from providing technical and financial support to entice farmers to recycle crop residues, heightened monitoring and implementation of applicable environmental regulations must also be pursued to deter farmers from burning crop residues. Tax and non-tax incentives may be offered likewise to attract investors to put up processing plants utilizing crop residues primarily for power generation.