Intercropping improves soil ecosystem multifunctionality through enhanced available nutrients but depends on regional factors

PurposeIntercropping is an important agricultural management that has been applied worldwide. Although intercropping improves soil nutrients and crop productivity, its effects on the microbial-mediated belowground processes and main drivers remain unclear.MethodsWe performed the same field study at two sites (Site1, Youyu; Site2, Zhangbei) by growing soybean and oat in monoculture and intercropping to investigate their effects on rhizosphere soil properties, enzyme stoichiometry, and soil ecosystem multifunctionality (EMF).ResultsIntercropping increased available phosphorus (Avail-P) by 87% and 16% for oat and soybean compared to the corresponding monoculture in site1, respectively. We also found that intercropping increased the C-acquiring and N-acquiring enzyme activities by 18%-48% in site1. Moreover, intercropping enhanced soil EMF and alleviated microbial P limitations for both oat and soybean compared to the corresponding monoculture in site1. However, all observed parameters were not affected by intercropping in site2, which may be due to the lower Avail-P, mineral nitrogen (Nmin), and precipitation in site2 compared to site1. Moreover, the soil EMF was strongly positively correlated with soil Nmin, Avail-P, air temperature, and precipitation.ConclusionTherefore, intercropping improves soil ecosystem multifunctionality by increasing available nutrients, which are regulated by regional factors.