Soil biota is decisive for overyielding in intercropping under low phosphorus conditions

Cereal/legume intercropping typically increase crop yield, however, the mechanisms through which soil microbes mediate overyielding in intercropping under different nutrient availability remain elusive. Here we examined the effect of soil biota and phosphate (P) availability on intercropping advantages in wheat (Triticum aestivum) /faba bean (Vicia faba) systems using a pot experiment consisting of soil sterilization treatment and different P supply levels. A complementary experiment on the contribution of different microbial groups was also included using the removal method. Intercropping advantage was observed only in the presence of microbes and was mainly associated with increase of wheat biomass. Overyielding effect was stronger under low-P than high-P conditions, and was negatively correlated with P availability and the effect of soil biota in the monoculture. The effect was likely related to the enlarged active P pools and modified microbial communities associated with the altera...禾本科-豆科间作通常可提升作物产量，但不同养分有效性条件下，土壤微生物介导间作超产效应的内在机制仍不明晰。本研究以小麦（Triticum aestivum）-蚕豆（Vicia faba）间作体系为研究对象，通过设置土壤灭菌处理与不同磷（P）供应水平的盆栽试验，探究了土壤生物群落与磷素有效性对间作优势的调控效应。本研究还采用移除法开展补充试验，以解析不同微生物类群的贡献作用。研究结果表明，仅在土壤微生物存在的条件下才可观测到间作优势，且该优势主要与小麦生物量提升相关。低磷条件下的间作超产效应显著强于高磷条件，且该效应与磷素有效性及单作体系中土壤生物群落的作用呈负相关关系。该效应可能与活性磷库的扩大以及伴随改变相关的微生物群落重构有关……