Can phosphorus application and cover cropping alter arbuscular mycorrhizal fungal communities and soybean performance after a five-year phosphorus-unfertilized crop rotational system?

backgroundUnderstanding diversity of arbuscular mycorrhizal fungi (AMF) is important for optimizing their role for phosphorus (P) nutrition of soybeans (

methodsIn this study, we established three cover crop systems (wheat, red clover and oilseed rape) or bare fallow in rotation with soybean. The P-application rates before the seeding of soybeans were 52.5 and 157.5 kg ha

resultsThe increase in the root colonization at the flowering stage was small as a result of P-application. Cover cropping did not affect the aboveground biomass and P uptake of soybean in both years, but the P-application had positive effects on the soybean performance such as plant P uptake, biomass and grain yield in 2015. AMF communities colonizing soybean roots were also significantly influenced by P-application throughout the two years. Moreover, the diversity of AMF communities in roots was significantly influenced by P-application and cover cropping in both years, and was positively correlated with the soybean biomass, P uptake and grain yield throughout the two years. DISCUSSION: Our results indicated that P-application rather than cover cropping may be a key factor for improving soybean growth performance with respect to AMF diversity in P-limited cover cropping systems. Additionally, AMF diversity in roots can potentially contribute to soybean P nutrition even in the P-fertilized cover crop rotational system. Therefore, further investigation into the interaction of AMF diversity, P-application and cover cropping is required for the development of more effective P management practices on soybean growth performance.