Comparative analysis of unmanned rice production methods in China: an evaluation of energy and economic benefits

To explore the potential application value of various unmanned rice planting methods, we performed quantitative comparisons of energy utilization and economic benefits for unmanned aerial seeding (UAS), unmanned dry direct seeding (UDDS), and unmanned carpet transplanting (UCT) from 2021 to 2023. The results showed that the total energy inputs in UAS and UDDS were significantly lower than that in UCT, reflecting decreases of 10.13 % and 13.84 %, respectively. UCT demanded considerably more diesel, water, plastics, and labor than the other methods, while UAS significantly reduced inputs of machinery, diesel, water, and labor but increased inputs of electricity, seeds, and farm chemicals. Meanwhile, UDDS further decreased diesel and water consumption despite more machinery input. Although both UAS and UDDS caused lower energy outputs of grain and straw yields, only UDDS showed a significant difference from UCT, while all methods exhibited similar net energy. Additionally, UAS and UDDS significantly outperformed UCT in energy use efficiency, profitability, and productivity, while also significantly reducing specific energy consumption. Both economic income and cost trends were UCT > UAS > UCT, with UAS and UCT differing significantly only in costs, while UDDS and UCT differed significantly in both indicators. However, there was no statical difference in net profit or net return rate among the methods. These findings suggest that UAS is promising for rice unmanned cultivation with the characteristics of low-cost and high-income and coordinating grain yield and food security.