Land use changes strongly impact soil functions, particularly microbial biomass diversity and activity. We hypothesized that the catabolic respiration response of the microbial biomass would differ depending on land use and that these differences would be consistent at the landscape scale. In the present study, we analyzed the catabolic response profile of the soil microbial biomass through sub...

Climate warming could increase rates of soil organic matter turnover and nutrient mineralization, particularly in northern high-latitude ecosystems. However, the effects of increasing nutrient availability on microbial processes in these ecosystems are poorly understood. To determine how soil microbes respond to nutrient enrichment, we measured microbial biomass, extracellular enzyme activities...

This study illustrated how crop residue-derived carbon interacts with non-residue carbon (e.g., native soil carbon) in agroecosystems and how carbon is allocated to soil organisms and respiration under different tillage regimes. The carbon dynamics in crop residue, soil microorganisms, nematodes and respiration were monitored using C-labeled corn residue. In addition, the carbon budget was esti...

Climate warming could increase rates of soil organic matter turnover and nutrient mineralization, particularly in northern high-latitude ecosystems. However, the effects of increasing nutrient availability on microbial processes in these ecosystems are poorly understood. To determine how soil microbes respond to nutrient enrichment, we measured microbial biomass, extracellular enzyme activities...

Empirical studies show that nitrogen (N) addition often reduces microbial decomposition of soil organic matter (SOM) and carbon dioxide (CO2) production via microbial respiration. Although predictions from theoretical models support these findings, the mechanisms that drive this response remain unclear. To address this uncertainty, we sampled soils of three grassland sites in the U.S. Central G...

The effects of heavy metals on soil microbial processes were investigated over a period of six weeks. Analytical grade (Sigma) sulphate salts of copper, zinc and nickel were added individually and in combinations to soil samples and incubated in different plastic pots. Samples were taken from the pots forthnightly and the rates of microbial carbon and nitrogen mineralization, microbial biomass ...

To address the combined effects of cadmium (Cd) and elevated CO2 on soil microbial communities, DGGE (denaturing gradient gel electrophoresis) profiles, respiration, carbon (C) and nitrogen (N) concentrations, loessial soils were exposed to four levels of Cd, i.e., 0 (Cd0), 1.5 (Cd1.5), 3.0 (Cd3.0) and 6.0 (Cd6.0) mg Cd kg(-1) soil, and two levels of CO2, i.e., 360 (aCO2) and 480 (eCO2) ppm. Co...

Climate change models predict that future precipitation patterns will entail lower-frequency but larger rainfall events, increasing the duration of dry soil conditions. Resulting shifts in microbial C cycling activity could affect soil C storage. Further, microbial response to rainfall events may be constrained by the physiological or nutrient limitation stress of extended drought periods; thus...

Climate warming is likely to increase the frequency and severity of forest disturbances, with uncertain consequences for soil microbial communities and their contribution to ecosystem C dynamics. To address this uncertainty, we conducted a meta-analysis of 139 published soil microbial responses to forest disturbances. These disturbances included abiotic (fire, harvesting, storm) and biotic (ins...

It is widely known that the carbon availability in the rhizosphere is much higher than in the bulk soil. However, studies have failed to show whether microbial respiration in the rhizosphere is carbon-limited. Precise and timely measurements are lacking. We measured carbon availability index (basal respiration divided by substrate-induced respiration), and water soluble carbon in soils sampled ...