Comparison of energy use between fully mechanized and semi-mechanized rice production in Southwest China.

This study performed energy analyses of fully mechanized rice production mode (FM) and semi-mechanized rice production mode (SM) in China. Fertilizer, fuel, and water were the three largest inputs, accounting for 92.02% of the total energy input. FM adopted side-deep fertilization with machine transplanting and implemented intermittent irrigation regime to improve water and fertilizer use efficiency. Compared with SM, FM reduced fertilizer and water energy inputs by 1252.62 MJ ha−1 and 2187.87 MJ ha−1, respectively. Because of the lower degree of mechanization, the fuel energy input of SM was 691.19 MJ ha−1 less than that of FM. The total average energy input of FM was 23,610 MJ ha−1, which was 10.80% lower than SM (26,470.01 MJ ha−1), whereas the rice and straw yields of FM were not significantly different from SM. The energy use efficiency, energy productivity, and energy profitability of FM were 11.10, 0.41 kg MJ−1, and 10.10, respectively, corresponding to increases of 8.56%, 8.61%, and 9.49% compared to SM. With appropriate agronomic measures in rice production, a higher degree of mechanization would not necessarily lead to an increase in energy input in Southwest China. [Display omitted] • Fully mechanized (FM) and semi-mechanized (SM) rice production modes were compared. • The energy consumption of SM increased by 12.11% on average compared to that of FM. • Fertilizer, fuel, and water accounted for about 92% of the total energy input. • Energy use efficiency and energy productivity of FM were higher than that of SM. • FM has more advantages than the SM. [ABSTRACT FROM AUTHOR]