Data from: Higher plant diversity does not moderate the influence of changing rainfall regimes on plant-soil feedback of a semi-arid grassland

Climate change is expected to increase the frequency of severe droughts,
but it remains unclear whether soil biotic conditioning by plant
communities with varying species richness or functional group diversity
moderate plant–soil feedback (PSF)—an important ecosystem process driving
plant community dynamics—under altered rainfall regimes. We conducted a
two‐phase PSF experiment to test how plant diversity affects biotic PSF
under different rainfall regimes. In Phase 1, we set up mesocosms with 15
plant assemblages composed of two grasses, two forbs and two
nitrogen‐fixing legumes [one, two, three, or six species from one, two, or
three functional group(s)] common to the semi‐arid eastern Eurasian
Steppe. Mesocosms were subjected to two rainfall amounts (ambient, 50%
reduction) crossed with two frequencies (ambient, 50% reduction) for a
growing season (~3 months). Conditioned soil from each mesocosm was then
used in Phase 2 to inoculate (7% v/v) sterilised mesocosms planted with
the same species as in Phase 1 and grown for 8 weeks. Simultaneously, the
same plant assemblages were grown in sterilised soil to calculate PSF
based on plant biomass measured at the end of Phase 2. Feedback effects
differed amongst plant assemblages, but were not significantly altered by
reduced rainfall treatments within any plant assemblage. This suggests
that the examined interactions between plant and soil microbial
communities were resistant to simulated rainfall reductions and that
increasing plant diversity did not moderate PSF under altered rainfall
regimes. Moreover, increasing plant species richness or functional group
diversity did not lessen the magnitude of PSF differences between ambient
and reduced rainfall treatments. Collectively, these findings advance our
understanding of plant diversity's potential to mitigate climate
change effects on PSF, showing that in semi‐arid grasslands, higher plant
diversity may not moderate PSF responses to altered rainfall regimes and
highlighting the importance of considering species‐specific traits and
interaction stability.