Carbon, Nitrogen and Water Footprints of Organic Rice and Conventional Rice Production over 4 Years of Cultivation: A Case Study in the Lower North of Thailand

An integrated method is required for comprehensive assessment of the environmental impacts and economic benefits of rice production systems. Therefore, the objective of this study was to apply different footprinting approaches (carbon footprint (CF), nitrogen footprint (NF), water footprint (WF)) and determine the economic return on organic rice farming (OF) and conventional rice farming (CVF) at the farm scale. Over the 4-year study period (2018-2021), the results showed lower net greenhouse gas (GHG) emissions in OF (3289.1 kg CO(2)eq ha(-1) year(-1)) than in CVF (4921.7 kg CO(2)eq ha(-1) year(-1)), indicating that the use of OF can mitigate the GHG emissions from soil carbon sequestration. However, there was a higher CF intensity in OF (1.17 kg CO(2)eq kg(-1) rice yield) than in CVF (0.93 kg CO(2)eq kg(-1) rice yield) due to the lower yield. The NF intensities of OF and CVF were 0.34 and 11.94 kg Neq kg(-1) rice yield, respectively. The total WF of CVF (1470.1 m(3) ton(-1)) was higher than that in OF (1216.3 m(3) ton(-1)). The gray water in CVF was significantly higher than that in OF due to the use of chemical fertilizers, herbicides, and pesticides. Although the rice yield in OF was nearly two times lower than that in CVF, the economic return was higher due to lower production costs and higher rice prices. However, more field studies and long-term monitoring are needed for future research.