An eco-engineering assessment index for chemical pesticide pollution management strategies to complex agro-ecosystems

Human inputs into complex agro-ecosystems, such as those involving rice production, have ecological, economic, and social effects that can be positive or negative. We here described positive effects using the term comprehensive profit (CP), which included ecological, economic and social profits. The negative effects are termed comprehensive cost (CC), including ecological, economic and social losses. To develop an eco-engineering assessment system based on these parameters, we used a matrix of the ratios of comprehensive cost to comprehensive profit (RCC/CP), where the RCC/CP index matrix WCC/CP is defined as the index optimization matrix of CC divided by the index optimization matrix of CP. We applied the basic principles and methods of Analytic Hierarchy Processes (AHP) to determine the comparative weight of indices derived in this manner as the basis for identifying one or more pesticide pollution management strategies for use in rice production systems in Shanghai, China. We used a generalized function to nondimensionalize the value of the index, and then to calculate the systematic evaluation index. The evaluating result range for CP used for this purpose was classified into 5 levels: excellent, better, general, bad and worst, as was the range for CC (very high, much high, common, much low and very low). Applying our assessment system (RCC/CP) for five different pest control strategies in rice fields gave the order of value of the strategies to be: “applying environment-friendly pesticides 6 times and frequency vibration lamps with rice–milk vetch rotation mode” (0.744) < “applying environment-friendly pesticides 5 times and frequency vibration lamps with rice–milk vetch rotation mode” (0.747) < “applying environment-friendly pesticides 5 times and postponing transplanting date with rice–milk vetch rotation mode” (0.753) < “applying environment-friendly pesticides 6 times and postponing transplanting date with rice–milk vetch rotation mode” (0.760) < “applying common pesticides 9 times and following conventional transplanting date with rice–wheat rotation” (0.930). The treatment “applying environment-friendly pesticides 6 times and frequency vibration lamps with rice–milk vetch rotation mode” was determined to be the optimal chemical pollution management strategy for use in rice fields in Shanghai, China.

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► We present RCC/CP matrix of ratios of comprehensive cost to comprehensive profit.
► We construct assessment system for chemical pesticide pollution management.
► The lower the RCC/CP index value is, the better the corresponding technology is.
► “pesticides 6 times + lamps + rice–milk vetch rotation” was the optimal strategy.