| Multi-cropping is a high-yield and high-efficiency characteristic planting mode in Southwest China,especially in hilly dry land of Sichuan Province.The evaluation and analysis of resource utilization and Eco-economic benefits of different planting modes are of great significance to the structural adjustment and optimization of planting modes and the promotion of sustainable agricultural development.This study was conducted from November 2016 to November 2018.Through two-year field positioning experiment,the material and energy production,economic benefits,resource utilization and ecological energy benefits of eight different cropping patterns in the hilly dryland of Sichuan Province were comprehensively evaluated and analyzed.The results are as follows:1.In terms of productivity of different planting modes,multi-cropping compound cropping mode is superior to two-cropping net planting mode in material and energy production,conversion of yield and economic benefits.The advantages of different multi-cropping modes are different.Among them,T5 "forage rape-spring maize/summer soybean" has the best biomass and energy production,and T6 "forage rape-spring maize‖peanut" has the best economic yield and material energy production.T7 "Potato-Spring Maize‖Peanut" has the best conversion of yield and economic benefits.2.In the comparison of resource utilization among different cropping patterns,the absolute amount and allocation rate of light-temperature and water resources in the multiple cropping modes were significantly better than that in the twocropping net cropping mode.The economic production efficiency of light,temperature,water resources and production efficiency of multi-cropping mode was better than that of twocropping net cropping mode,and the economic efficiency of intercropping mode was better than that of intercropping mode under the same sowing date.T5 "forage rape-spring maize/summer soybean" and T6 "forage rape-spring maize‖peanut" were superior to the two-cropping net cropping mode in terms of light,temperature and water resources biological yield production efficiency,and the intercropping mode was superior to the intercropping mode.T6 "Potato-spring maize‖peanut" is a double-optimal model for comprehensive utilization of climatic resources of economic yield and biological yield in the comprehensive evaluation of utilization rate of climatic resources of light,temperature and water.3.Compared with the two cropping modes,the multi-cropping mode shortened the growth period to reduce the negative effect of precipitation,stabilized the distribution of light,temperature and water resources,and tapped the potential of accumulated temperature production.Compared with the twocropping net cropping system,intercropping spring maize with multiple cropping modes could earlier sowing and harvesting period,avoid the influence of summer waterlogging on yield,and the intercropping system showed water compensation benefits to alleviate the impact of spring drought,and cope with the system production stability of light,temperature and water resources change: intercropping > intercropping > net cropping.The annual intercropping mode of multiple cropping is more stable and efficient than the net cropping mode of double cropping in the interannual climate change.4.In the comparison of eco-economic benefits of emergy theory,the emergy input rate,purchasing emergy ratio and emergy density of multi-cropping mode are higher than those of twocropping net cropping mode.The level of modernization and intensification is higher,and it has more economic competitive advantages.T7 "potato-spring maize‖peanut" is the best,and the emergy output rate of T2 "rape-summer maize" is the highest.In terms of ecological benefits,multi-cropping mode is less than dual-cropping net cropping mode in terms of energy self-sufficiency,system production superiority and environmental load.It relies less on the environment,has smaller internal uniformity and less environmental pressure.T7 "Potato-spring maize‖peanut" is the best.In terms of comprehensive ecological and economic benefits,the sustainable index and system stability index of the overall multiple cropping mode are better than the two-cropping net cropping mode,the stability and sustainability of the multiple cropping model are better,and the T7 "potato-spring maize‖peanut" is the best.5.In the benefit analysis of AHP comprehensive index,T7 "potato-spring maize‖peanut" model pays more attention to quantity advantage,T5 "forage rape-spring maize/summer soybean" pays more attention to efficiency advantage,among which T5 is the best.T5 "forage rape-spring maize/summer soybean" is the best in ecological benefit,and it is superior to other models in material,energy and land use efficiency.T7 "potato-spring maize‖peanut" is the best in social benefits.In the comprehensive evaluation of the three benefits,the overall multiple cropping model is better than the double cropping model.Among them,T5 "forage rape-spring maize/summer soybean" is an agricultural sustainable model that takes into account economic,ecological and social benefits.In conclusion,the multi-cropping mode is better than the two-cropping net cropping mode,and the intercropping system is superior to the single cropping system in terms of economic performance,biological performance,resource utilization and value-based ecological and economic benefits.Winter forage rape and potato have different prominent advantages over grain and oil production,and they are ideal substitutes for winter crops.It shows that while developing the advantages of intercropping maize in summer and autumn,it is necessary to fully tap and utilize the high productive potential and high efficiency characteristics of winter forage and cash crops relative to grain and oil crops.T5 "forage rape-spring maize/summer soybean" is the optimum mode of biomass,material and energy production,biomass,light,temperature,water resources production efficiency and AHP comprehensive index benefit.T6 "forage rape-spring maize‖peanut" is the optimal model for economic yield,material and energy production,yield increase potential,comprehensive utilization of resources and system stability.T7 "Potato-Spring Maize‖Peanut" is the best mode of eco-economic stability and sustainability in conversion of yield,economic benefit and value analysis. |
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