zero tillage practices have a direct effect on soil microbial communities modifying soil productivity and sustainability. the crop sequences used can change the aforementioned properties, too. in this study, we evaluated the effect of crop sequences under zero tillage management on soil biological and chemical properties including vertical distribution of soil organic carbon, soil basal respira...

The contamination of agricultural soils by heavy metals is a global problem. Soil texture as a biotic factor represents one of the most important factors that influences the distribution of organic matter and ultimately play decisive role in retention of heavy metals in soil ecosystem. The effects of heavy metals on soil microbial processes were investigated. Analytical grade sulphate and chlor...

land use change of forest ecosystems in northern iran changes the soil quality of paresar (gilan province) and gorgan (gorgan province) regions. in order to study changes in some biological soil quality indices due to land use change from forest to cultivated lands, composite soil samples from two depths (0-20 and 20-40 cm) were taken from paresar and gorgan regions and urease, alkaline and aci...

Temperature is an important factor regulating microbial activity and shaping the soil microbial community. Little is known, however, on how temperature affects the most important groups of the soil microorganisms, the bacteria and the fungi, in situ. We have therefore measured the instantaneous total activity (respiration rate), bacterial activity (growth rate as thymidine incorporation rate) a...

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 ...

Heterotrophic respiration contributes a substantial fraction of the carbon flux from soil to atmosphere, and responds strongly to environmental conditions. However, the mechanisms through which short-term changes in environmental conditions affect microbial respiration still remain unclear. Microorganisms cope with adverse environmental conditions by transitioning into and out of dormancy, a st...