Mechanisms linking plant community properties to soil aggregate stability in an experimental grassland plant diversity gradient

Abstract

Background and aims Soil aggregate stability depends on plant community properties, such as functional group composition, diversity and biomass production. However, little is known about the relative importance of these drivers and the role of soil organisms in mediating plant community effects. Methods We studied soil aggregate stability in an experimental grassland plant diversity gradient and considered several explanatory variables to mechanistically explain effects of plant diversity and plant functional group composition. Three soil aggregate stability measures (slaking, mechanical breakdown and microcracking) were considered in path analyses. Results Soil aggregate stability increased significantly from monocultures to plant species mixtures and in the presence of grasses, while it decreased in the presence of legumes, though effects differed somewhat between soil aggregate stability measures. Using path analysis plant community effects could be explained by variations in root biomass, soil microbial biomass, soil organic carbon concentrations (all positive relationships), and earthworm biomass (negative relationship with mechanical breakdown). Conclusions The present study identified important drivers of plant community effects on soil aggregate stability. The effects of root biomass, soil microbial biomass, and soil organic carbon concentrations were largely consistent across plant diversity levels suggesting that the mechanisms identified are of general relevance

Plant species richness and functional groups have different effects on soil water content in a decade‐long grassland experiment

“…After the cropland was converted to grassland, the soil structure, originally destroyed by ploughing, redeveloped via the formation of aggregates and continuous pores with the potential to connect top‐ and subsoil quickly. Both soil aggregate and pore formation are closely related to several biotic factors within the soil compartment, which are affected by plant diversity, for example, soil microbial biomass and activity (Eisenhauer et al, ) and soil fauna (Eisenhauer et al, ), SOC concentration (Lange, Eisenhauer, et al, ; Steinbeiss et al, ), and root biomass (Ravenek et al, ) and accordingly previous research has showed diversity effects on aggregate stability (Gould et al, ; Pérès et al, ). Our results suggest that soil structure formation progresses faster in plots with more plant species.…”

“…Besides direct effects on water fluxes (evaporation and transpiration), plant community composition, including species richness and functional group assembly, influences soil functions such as soil microbial biomass and activity (Drenovsky, Vo, Graham, & Scow, ; Eisenhauer et al, ; Lange et al, ; Zak, Holmes, White, Peacock, & Tilman, ), soil fauna (Eisenhauer et al, ), and soil organic matter dynamics (Lange, Eisenhauer, et al, ; Steinbeiss et al, ), all of which affect soil properties related to soil water percolation, such as soil aggregation (Gould et al, ; Pérès et al, ), soil pore volume, and water infiltration capacity (Fischer et al, ). The close relationship between the biogeochemical and water cycles can incur further indirect effects of biodiversity on the availability of other resources that are mediated by soil water (Allan et al, ; Loreau & Hector, ; Tilman et al, ).…”

Direct and indirect effects of glomalin, mycorrhizal hyphae and roots on aggregate stability in rhizosphere of trifoliate orange

“…Meanwhile, water-stable aggregates (WSAs) in macroaggregates, which are stable to the action of repeated soil wetting and drying cycles, are widely used to evaluate aggregate stability by means of the wet-sieving analysis6. As an indicator of soil structure related to soil water regime, erodibility, and nutrient availability, aggregate stability is affected by soil physical, chemical, and/or microbial community properties, root systems, plant species and/or communities78910.…”

Biodiversity Agriculture Supports Human Populations

“…Soil aggregate stability increased signifi cantly from monocultures to plant species mixtures ( Pérès et al 2013 ). Root-derived carbon (C) is preferentially retained in soil compared to aboveground C inputs, and microbial communities assimilating rhizodeposit-C are sensitive to their microenvironment.…”