Abstract: Proper field arrangements are essential for sustainable agricultural ecosystem. Using emergy theory and method, this paper analyzed the differences of emergy input and output, environmental loading rate and emergy sustainability index under four cultivation modes: 2∶2 cornsoybean strip intercropping (M/S1), cornsoybean traditional intercropping 1∶1 (M/S2), maize monoculture (M) and soybean monoculture (S), in order to provide reference for optimized arrangement of farmlands. The results showed that the emergy inputs were in order of M/S2>M/S1>M>S. Fertilizer input accounted for a large proportion of subsidiary industrial emergy, and labor input accounted for a large proportion of renewable organic emergy. The emergy outputs were in order of M/S1>M/S2>S>M. Compared with maize, soybean had higher energy output, lower energy input, lower environmental load rate, higher emergy sustainability index. Economic benefits of M/S1, M/S2 and M were higher than that of mode S. In order to further optimize M/S1, we should reduce fertilizer input, especially phosphorus and potassium fertilizer, reduce the frequency and depth of farming, and increase the density of soybean, reduce density of maize, reduce environmental load rate and improve the emergy sustainability index.

Key words: rotation cropping, sorghum, soil environment, microbial community, continuous cropping obstacle.