Energy and Carbon Input-Output Analysis of Tomato Production in Barangay La Paz, Zamboanga City, Philippines

The study on tomato production was carried out in the barangay La Paz in Zamboanga City, Philippines, to estimate the carbon input and output and determine the tomato production system's carbon efficiency ratio. The input carbon has calculated from the total energy input (TEI), which is the sum of "direct energy input (DEI), indirect energy input (IEI), and embedded energy input (EEI). The tomato production produced a total input carbon of 2,444.51 CO2e kg-1 . To obtain the CO2 emission equivalent, the TEI in Mcal units has been converted into Liter Diesel Oil Equivalent (LDOE), where 1.0 LDOE equals 11.414 Mcal unit-1 multiplied by 3.96. The results indicated that crop care and management activity received the most input carbon, with a potential CO2 emission equivalent of 74.91%, followed by harvest and pre-harvest activity (9.41%) and pre-planting operation (8.10%). Crop establishment obtained the lowest input carbon at 7.58% CO2e potential share. The tomato production produced 2,454.66 CO2e kg ha-1 of output carbon, resulting in a total of 10.15 net CO2e kg ha-1 . To the carbon efficiency (ratio), output carbon divided by input carbon has the result of 1.0. The carbon efficiency ratio has correlated with the typical yield of tomatoes. It demonstrates that the city's existing cultural practices for producing tomatoes led to positive carbon sequestration rates, whereas it does not emit carbon beyond the output carbon produced from the production of tomatoes. It indicates that tomato is one of the carbon-neutral crops because the a