Data from: Soil aggregate stability and grassland productivity associations in a northern mixed-grass prairie

Soil aggregate stability data are often predicted to be positively
associated with measures of plant productivity, rangeland health, and
ecosystem functioning. Here we revisit the hypothesis that soil aggregate
stability is positively associated with plant productivity. We measured
local (plot-to-plot) variation in grassland community composition, plant
(aboveground) biomass, root biomass, % water-stable soil aggregates, and
topography. After accounting for spatial autocorrelation, we observed a
negative association between % water-stable soil aggregates (0.25-1 and
1-2 mm size classes of macroaggregates) and dominant graminoid biomass,
and negative associations between the % water-stable aggregates and the
root biomass of a dominant sedge (Carex filifolia). However, variation in
total root biomass (0-10 or 0-30 cm depths) was either negatively or not
appreciably associated with soil aggregate stabilities. Overall,
regression slope coefficients were consistently negative thereby
indicating the general absence of a positive association between measures
of plant productivity and soil aggregate stability for the study area. The
predicted positive association between factors was likely confounded by
variation in plant species composition. Specifically, sampling spanned a
local gradient in plant community composition which was likely driven by
niche partitioning along a subtle gradient in elevation. Our results
suggest an apparent trade-off between some measures of plant biomass
production and soil aggregate stability, both known to affect the
land's capacity to resist erosion. These findings further highlight
the uncertainty of plant biomass-soil stability associations.