Temporal dynamics of biodiversity effects and light‐use‐related traits in two intercropping systems

Abstract

AbstractIntroductionIntercropping systems can be more productive than their respective monocultures and this positive net biodiversity effect is caused by complementarity and selection effects. While the complementarity effect is caused through resource partitioning or facilitation, the selection effect operates via the greater probability that a more diverse community contains a dominant and high‐yielding species which will account for the majority of productivity in that community. Here, we investigated how light‐use‐related traits contribute to the net biodiversity effect via complementarity or selection effects and how these qrelationships change throughout an annual growing season.Materials and MethodsWe conducted weekly destructive harvests to examine temporal dynamics of biodiversity effects in two crop mixtures (oat–lupin and oat–camelina) and their respective monocultures. We linked the biodiversity effects to traits related to light use (i.e., light interception, plant height, photosynthetic efficiency and photosynthetic capacity) and investigated how these relationships changed over time.ResultsWe found that the net biodiversity and selection effect increased over time in both mixtures, while complementarity effects increased only in the oat–lupin mixture. More intercepted light and taller plants in mixtures compared to monocultures positively contributed to biodiversity effects in both mixtures. Strategies for shade tolerance differed between the mixtures, that is, increased photosynthetic capacity and increased photosynthetic efficiency contributed to a positive net biodiversity effect in the oat–lupin and oat–camelina mixture, respectively.ConclusionBy linking the temporal dynamics of the net biodiversity effect and its two additive components to light‐use‐related traits in two different crop mixtures, this study demonstrates that complementary light use contributes to overyielding in intercropping systems. Such understanding is important for the design of effective intercropping systems and developing new crop cultivars suited to these environments.