Land management practices that simultaneously improve soil properties are crucial to high crop production and minimize detrimental impact on the environment. The effects of crop residues on crop performance, the fluxes of soil N 2O and CO 2 under wheat-maize (WM) and/or faba bean-maize (FM) rotations in Amorpha fruticosa (A) and Vetiveria zizanioides (V) intercropping systems on a loamy clay soil, in subtropical China, were examined. Crop performance, soil N 2O and CO 2 as well as some potential factors such as soil water content, soil carbon, soil nitrogen, microbial biomass and N mineralization were recorded during 2006 maize crop cultivation. Soil N 2O and CO 2 fluxes are determined using a closed-based chamber. Maize yield was greater after faba bean than after wheat may be due to differences in supply of N from residues. The presence of hedgerow significantly improved maize grain yields. N 2O emissions from soils with maize were considerably greater after faba bean (345 g N 2O-N ha -1) than after wheat (289 g N 2O-N ha -1). However, the cumulated N 2O emissions did not differ significantly between WM and FM. The difference in N 2O emissions between WM and FM was mostly due to the amounts of crop residues. Hedgerow alley cropping tended to emit more N 2O than WM and FM, in particular A. fruticosa intercropping systems. Over the entire 118 days of measurement, the N 2O fluxes represented 534 g N 2O-N ha -1 (AWM) and 512 g N 2O-N ha -1 (AFM) under A. fruticosa species, 403 g N 2O-N ha -1 (VWM) and 423 g N 2O-N ha -1 (VFM) under Vetiver grass. A significantly higher CO 2 emission was observed in AFM (5335 kg CO 2-C ha -1) from June to October, whereas no significant difference was observed among WM (3480 kg CO 2-C ha -1), FM (3302 kg CO 2-C ha -1), AWM (3877 kg CO 2-C ha -1), VWM (3124 kg CO 2-C ha -1) and VFM (3309 kg CO 2-C ha -1), indicating the importance of A. fruticosa along with faba bean residue on CO 2 fluxes. As a result, crop residues and land conversion from agricultural to agroforestry can, in turn, influence microbial biomass, N mineralization, soil C and N content, which can further alter the magnitude of crop growth, soil N 2O and CO 2 emissions in the present environmental conditions.
