Efficiency analysis of comprehensive utilization of agricultural resources under organic and conventional agricultures*— A case study of rice cultivation systems in Hubei Province

The aim of organic agriculture is to augment ecological processes which foster plant nutrient uptake and conserve soil and water resources by eliminating agrochemicals and reducing other external inputs. However, the superiority of organic agriculture in terms of resources utilization is still unclear. Thus this study established an evaluation index system of agricultural resources utilization efficiency and used it to compare the properties of agricultural resources utilization between conventional and organic rice cultivation systems. In the first case, the study systematically analyzed resources behavioral patterns under rice cultivation processes and the existing evaluation index system. In the analysis, 6 evaluation factors (including 18 indices) were selected for the evaluation index system. The Delphi method and Analytic Hierarchy Process (AHP) were used to determine weight coefficient of each index. The weight coefficient of climate resources factors was 16%, which included light use efficiency, heat use efficiency and rain use efficiency. The weight coefficient of water resources factors was 19%, which included irrigation index and water productivity index. Land resources factors (including reclamation rate, land productivity and multi-cropping index) had the highest weight coefficient (24%) in the evaluated index system. The weight coefficient of biotic resources factors was 19%, which included the Shannon-wiener index, economic yield and straw return rate. Labor cost factors (including input-output ratio, labor productivity, scientific technology contribution and agricultural commodity rate) accounted for 16% of the weight coefficient system. Resources sustainability factors (including soil nutrient balance, water environmental quality and resource stability) gave the lowest weight coefficient (10%) in the evaluated index system. In the second case, an empirical analysis was carried out in Hubei Province using the index system to compare resource utilization efficiency between organic and conventional rice cultivation systems in different years. Some 39 samples, which included 8 organic rice cultivation samples (4 samples from organic certification under 3 years, 1 sample from organic certification over 6 years, 4 samples from organic certification for 3 to 6 years) and 31 conventional rice cultivation samples, were used in the analysis. The results showed that the scores of organic cultivation for climate and land resources were lower than that of conventional cultivation. This was attributed to the lower biomass yield in organic cultivation; and the much higher scores of organic cultivation for water resources, biotic resources, labor cost and the related sustainability. Generally, the evaluation score of comprehensive utilization of resources of the 3-year organic rice cultivation was 0.867, similar to that of conventional rice cultivation (0.857). However, the evaluation score increased gradually with cultivation time (the evaluation score of 3 to 6 years organic cultivation was 0.927) and peaked (0.976) in over 6 years organic cultivation, which represented an increase of 14% compared with conventional cultivation. The results suggested that organic agriculture was superior to conventional agriculture in terms of resource utilization efficiency, but this difference was not obvious in the early stages of organic cultivation. The comprehensive utilization efficiency of resources of organic model developed in this study would be more applicable after long-term cultivation.