Energy Bill of Rice (Oryza sativa) in Calbayog City, Samar, Philippines
Philippine agriculture is an energy user of oil for production such as tillage, farm input applications, irrigations, postproduction, and up to cooking. Rice production in the Philippines, particularly Samar, is heavily dependent on fossil fuel–based inputs. Energy accounting in agriculture is an approach where energy consumption of different farm activities is determined with the view of improving fossil energy use. Energy was divided into three types: direct energy (fuel used to run machines and vehicles), indirect energy (petroleum used for the manufacture of inorganic fertilizers and chemical pesticides), and embedded energy (energy expended to operate machines, equipment, farm implements, farm tools, and motorized vehicles, and draft animals). The study was conducted to account for the energy bill per hectare of rice and identify the practices from production to postharvest activities that consume high levels of energy. A total of 115 rice growers of Calbayog City were interviewed using a survey questionnaire in 2017. The energy bill analysis showed that the total energy bill in various field productions per hectare of milled rice was 4533.60 Mcal or 397.20 L diesel oil equivalent (LDOE), which can be broken down as follows: indirect energy at 95.35% (4322.98 Mcal ha–1 or 378.74 LDOE), direct energy at 4.24% (192.33 Mcal ha–1 or 16.85 LDOE), and embedded energy at 0.41% (18.29 Mcal ha–1 or 1.60 LDOE). Indirect energy expended the highest energy bill, which was contributed by the chemical fertilizers.