Effect of maize intercropped with alfalfa and sweet clover on soil carbon dioxide emissions during the growing season in North China Plain

Many studies have demonstrated that various agricultural managements can reduce soil carbon dioxide (CO2) emission and intercropping systems is beneficial (such as higher production, effective nutrient acquisition, control of soil erosion, et al.). However, few studies have investigated whether intercropping systems can decrease soil CO2 emission. We thus carried out a field experiment to compare such emissions produced by monocultural maize (M) and maize-legume intercropping systems (maize intercropped with Alfalfa (MA), and maize intercropped with Sweet Clover (MSC)) in 2010. Results showed that mean seasonal fluxes of CO2 was greater for M than that for the intercropped plots. Cumulative CO2 flux for MA was significantly reduced by 14% compared to M (6.83 t ha(-1)) (P<0.05). There were no signicant correlations between daily CO2 emission and soil temperature or moisture during the observed period under dry environmental condition (P<0.05). Grain yield was slightly higher in M than that in MA and MSC but there was no difference (P<0.05). In summary, our result indicated that appropriate maize-legume intercropping pattern could significantly reduce soil CO2 emission without grain yield loss.