Soil microbial community composition and respiration along an experimental precipitation gradient in a semiarid steppe

Abstract

As a primary limiting factor in arid and semiarid regions, precipitation strongly influences soil microbial properties. However, the patterns and mechanisms of soil microbial responses to precipitation have not been well documented. In this study, changes in soil microorganisms along an experimental precipitation gradient with seven levels of precipitation manipulation (i.e., ambient precipitation as a control, and ±20%, ±40%, and ±60% of ambient precipitation) were explored in a semiarid temperate steppe in northern China. Soil microbial biomass carbon and respiration as well as the ratio of fungal to bacterial biomass varied along the experimental precipitation gradient and peaked under the +40% precipitation treatment. The shifts in microbial community composition could be largely attributable to the changes in soil water and nutrient availability. The metabolic quotient increased (indicating reduced carbon use efficiency) with increasing precipitation due to the leaching of dissolved organic carbon. The relative contributions of microbial respiration to soil and ecosystem respiration increased with increasing precipitation, suggesting that heterotrophic respiration will be more sensitive than autotrophic respiration if precipitation increases in the temperate steppe as predicted under future climate-change scenarios.

Pedotransfer Functions in Earth System Science: Challenges and Perspectives

“…Major soil microbial and mycorrhizal activity of heterotrophic respiration and nutrient mineralization are strongly affected by soil moisture content (Zhao et al, ). Both hydrologic variability and its effects on soil moisture (Rodriguez‐Iturbe & Porporato ) transferred on decomposer activity need to be accounted for in mathematical models of soil C and nutrient cycling.…”

Intensified Precipitation Seasonality Reduces Soil Inorganic N Content in a Subtropical Forest: Greater Contribution of Leaching Loss Than N2O Emissions

“…This is consistent with findings from rainfall reduction experiments in arid and semiarid ecosystems (Reichmann et al, ). The increase in soil inorganic N content after rainfall exclusion in arid and semiarid ecosystems was mainly attributed to decreased plant N uptake and microbial immobilization with reduced SWC (Reichmann et al, ; C. Zhao et al, ). In our study, however, plant N uptake may not have decreased, because the average SWC (27%) following extension of the dry season was still higher than the permanent wilting coefficient (SWC 19%) of the trees growing in the plots; the permanent wilting coefficient has been documented as a threshold of water stress for plant growth (Briggs & Shantz, ).…”

Interações Bióticas Entre Actinobactérias E Rizóbios Em Solos Da Região Semiárida Brasileira

“…Os microrganismos no solo são fortemente influenciados por vários fatores químicos e físicos, incluindo a disponibilidade de nutrientes, matéria orgânica, umidade do solo e temperatura (GORLACH-LIRA ; COUTINHO, 2007;FREITAS et al, 2014;ZHAO et al, 2016).…”

“…A produção de enzimas hidrolíticas extracelulares, como proteases, amilases, celulases e quitinases no solo semiárido, caracterizadas pela disponibilidade limitada de nutrientes, bem como o efeito rizosférico, podem contribuir grandemente para o crescimento e sobrevivência da população bacteriana (MAESTRE et al, 2010;SOUTO et al, 2013;ZHAO et al, 2016).…”