Response of belowground communities to short-term phosphorus addition in a phosphorus-limited woodland

Abstract

Aims Soil biota regulate essential ecosystem processes but our understanding of how soil fertility constrains biotic interactions remains limited. We investigated belowground responses to short-term phosphorus (P) fertilization in a P-limited woodland. Methods Ten Eucalyptus tereticornis were randomly selected and five fertilized with superphosphate equivalent to 50 kg P ha −1 over 6 months. We estimated aboveground (understory) and belowground plant biomass, and collected samples for soil chemistry, arbuscular mycorrhizal (AM) root colonization, soil fungal abundance and community composition, and extraction of nematodes and microarthropods. Results P-fertilization increased root biomass, abundance of non-AM fungi, and abundances of Collembola, and altered fungal community structure, but was associated with a decrease in predatory nematodes. Structural equation modelling indicated that effects on Collembola and fungal abundances were mediated by direct effects of the fertilizer treatment and/or indirect effects via root biomass responses. However, fungal community compositional changes and reductions in predatory nematodes resulted primarily due to fertilization-mediated changes in soil pH. Conclusion Our study shows that understory plant communities and soil biota are P-limited at the study site but that some biotic groups appear to be more sensitive to changes in soil pH than to increases in P availability.

Canopy leaf area of a mature evergreen Eucalyptus woodland does not respond to elevated atmospheric [CO2] but tracks water availability

“…Based on this L estimate and the relationship across FACE sites reported by Norby & Zak (), we expected about a 30% increase in L under eC a . In contrast to other forest FACE sites, the EucFACE is strongly limited by nutrient availability, in particular phosphorus (Crous et al ., ; Nielsen et al ., ). Hence, it may be too early to draw general conclusions across FACE sites in terms of L response.…”

Influence of phosphorus application and water deficit on the soil microbiota of N2‐fixing and non‐N‐fixing tree

“…This will consequently impede the nutrient availability for microbiota and decrease the microbial mediated enzyme activities (Nielsen et al. , Zhang et al. ).…”

“…), plant and soil microbiota responses to P addition could sometimes be inconsistent (Nielsen et al. ) due to different soil moisture conditions and the identity of the aboveground tree species in terms of their physiological needs, survival strategies, or contribution (quality and quantity of nutrient input) to soil the environment (Tang et al. ).…”

“…Despite the importance of P in terrestrial ecosystem, very few studies have examined its effects in relation to other abiotic factors, such as water, as well as with the specific identity of the aboveground plant species (e.g., fast‐ and slow‐growing trees, native and exotic trees, and nitrogen and non‐nitrogen‐fixing trees) on soil microbiota under drought stress (Nielsen et al. , Tang et al. ).…”

“…Drought stress has been reported to reduce the water potential of the soil physical matrix and enhances phosphorus deficiency by reducing it acquisition, mobility, and accessibility in the soil for plants and soil biota including protozoa, microbes, nematodes, and microarthropods (Nielsen et al. , Cavagnaro ). Despite the general understanding of the impacts of climate‐related alteration on soil ecosystems, the influence of its possible interaction with other abiotic factors is not well understood.…”