成都平原不同秸秆还田模式下稻麦轮作农田系统能值分析

目的]探索成都平原高产条件下稻麦轮作农田系统适宜的秸秆还田模式,为区域秸秆资源的农业循环再利用和农田系统的可持续发展提供一定的实践指导与科学依据。方法]在田间定位试验中,设置了常规施肥(CF)、秸秆半量还田(CFS1)、秸秆全量还田(CFS2)和秸秆1.5倍量还田(CFS3)4种施肥模式,应用能值分析方法探讨了不同农田系统的能值投入产出总量、结构及综合指标的变化。结果](1)从能值结构看,较CF模式,秸秆还田模式降低了农田系统能值投入中工业辅助能的比重,增强了系统的自给能力,并提高了系统总能值产出;(2)从能值指标看,较CF模式,秸秆还田模式提高了农田系统的净能值产出率、能值投入率、能值反馈率、能值生产力和能值—劳动生产率,降低了环境负载率,有效提升了农田系统的可持续发展性能,增强了系统的发展潜力,其中CFS2和CFS3模式的养分物质内部循环利用率较高,环境负载率较小,有利于农田系统的持续、高效运行。结论]CFS2和CFS3模式是成都平原稻麦轮作农田较优的秸秆还田生产模式。

Emergy Analysis of Farmland Eco-system with Different Straw Returning Modes of Rice-Wheat Rotation in Chengdu Plain

Objective] To find out a suitable straw returning mode for the rice-wheat rotation ecosystem with high yield in Chengdu Plain, and to offer a scientific basis for the efficient operation of regional farmland system.Methods] Four treatments in field experiment was designed according to applied straw quantities, i.e., chemical fertilizer only(CF), chemical fertilizer plus a half of straw returning(CFS₁), chemical fertilizer plus total straw returning(CFS₂), chemical fertilizer plus 1.5 times of straw returning(CFS₃). Based on emergy analysis method, we studied the changes of total amount of emergy input and output, the structure of emergy input and output and the emergy indexes among different fertilization treatments.Results] (1) The results showed that, as compared to CF mode, other straw returning modes lowered the proportion of the non-renewable industrial assistant emergy to the total emergy input and increased the level of self-supply ability and the total emergy output. (2) From the perspective of the emergy indexes, as compared to the CF mode, straw returning modes had higher levels of net emergy yield ratio, emergy input ratio, emergy feedback ratio, emergy productivity and emergy-labor productivity, and had lower levels of environmental load ratio. Straw returning modes effectively improve the sustainable development ability of farmland system, especially CFS₂ and CFS₃ modes had the lower environmental load ratio and the higher emergy sustainable index.Conclusion] Modes of CFS₂ and CFS₃ are the suitable straw returning modes under a rice-wheat rotation in Chengdu Plain.