LCA on Lettuce Cropping System by Top-down Method in Protected Cultivation

Abstract

This study was carried out to estimate carbon emission using LCA (Life Cycle Assessment) and to establish LCI (Life Cycle inventory) DB for lettuce production system in protected cultivation. The results of data collection for establishing LCI DB showed that the amount of fertilizer input for 1 kg lettuce production was the highest. The amounts of organic and chemical fertilizer input for 1 kg lettuce production were 7.85E-01 kg and 4.42E-02 kg, respectively. Both inputs of fertilizer and energy accounted for the largest share. The amount of field emission for CO₂, CH₄ and N₂O for 1 kg lettuce production was 3.23E-02 kg. The result of LCI analysis focused on GHG (Greenhouse gas) showed that the emission value to produce 1 kg of lettuce was 8.65E-01 kg CO₂. The emission values of CH₄ and N₂O to produce 1 kg of lettuce were 8.59E-03 kg CH₄ and 2.90E-04 kg N₂O, respectively. Fertilizer production process contributed most to GHG emission. Whereas, the amount of emitted nitrous oxide was the most during lettuce cropping stage due to nitrogen fertilization. When GHG was calculated in CO₂-equivalents, the carbon footprint from GHG was 1.14E-+00 kg CO₂-eq. kg-¹. Here, CO₂ accounted for 76% of the total GHG emissions from lettuce production system. Methane and nitrous oxide held 16%, 8% of it, respectively. The results of LCIA (Life Cycle Impact assessment) showed that GWP (Global Warming Potential) and POCP (Photochemical Ozon Creation Potential) were 1.14E+00 kg CO₂-eq. kg-¹ and 9.45E-05 kg C₂H₄-eq. kg-¹, respectively. Fertilizer production is the greatest contributor to the environmental impact, followed by energy production and agricultural material production.