Effects of wheat/faba bean intercropping on soil nitrogen transformation processes

摘要

Purpose Intercropping can increase crop production and maintain soil organic matter levels in soil. The underlying mechanisms are associated with above- and below-ground nutrient (e.g., nitrogen) availability, uptake, and use efficiency. The aims of this study were to identify the effect of the N availability improvement on yield of intercrops and to explore soil N transformation rates in rhizosphere soil of wheat/faba bean intercrops, as compared with their sole crops.Materials and methods In a field experiment, crops productivity was measured and rhizosphere soils of intercropped and monocropped wheat/faba bean were collected to examine changes of soil gross N transformation rates via a nitrogen-15 (N-15) incubation study.Results and discussion Intercropping significantly increased the productivity. Grain yields of intercropped faba bean and wheat were 11.4 and 34.2% higher than those of the corresponding monocrops, respectively. The gross and net rates of organic N mineralization and nitrification, as well as the gross mineral N immobilization rates were considerably greater in intercropping compared to the sole cropping system. The results suggested that the increased grain yield during intercropping was related to an improved capacity of N supply and conservation in soils via an intensification of the mineralization-immobilization turnover (MIT) and intercropping enhanced mineral N availability.Conclusions Our findings demonstrated that wheat/faba bean intercropping was able to significantly increase the productivity of both companion crops under subtropical condition. The environmental implication of NO3- leaching and runoff under monocropping conditions could be alleviated by adopting an intercropping management.