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...