Assessment of conventional and highly mechanized rice production systems using life cycle assessment (LCA) approach.

Abstract

A well-managed and judicious utilization of energy from fossil fuel, chemical fertilizers, and pesticides in intensive rice production may favor less GHG emission and not contribute to global warming as well. To avoid high emissions in rice production, there is a need to thoroughly look into factors that contribute to increased emissions and recommend ways of reducing them. This study used LCA (Life Cycle Assessment) to compare farm inputs in conventional or common farmer's practice and highly mechanized rice production systems through actual field experimentation. Generally, inbred and hybrid varieties had similar energy efficiencies, as well as GHG emissions for both dry and wet seasons. Energy inputs (10,714 MJ/ha) of transplanted rice production for both conventional and highly mechanized farming were higher compared to directseeded rice. It also had higher cost of production owing to more human labor-days employed, and had higher GHG emissions. Rice production during the dry season had higher energy efficiency, owing to lower energy input, production cost, and GHG emissions. Direct-seeded rice using machine is advantageous in terms of cost, number of human labor-days, energy input, GHG emissions, and time of machine operations. Conventional rice production cost was 39.9% higher compared to highly mechanized, resulting from the number of human labor employed and time of machine operations. Energy output-input ratio and GHG emission were higher in highly mechanized production compared to conventional. Additionally, mechanized production in the dry season had higher yield, and higher energy efficiency compared to conventional.