Gross NO Production Process, Not Consumption, Determines the Temperature Sensitivity of Net NO Emission in Arable Soil Subject to Different Long-Term Fertilization Practices.

Chronic amendment of agricultural soil with synthetic nitrogen fertilization and/or livestock manure has been demonstrated to enhance the feedback intensity of net NO emission to temperature variation (i.e., temperature sensitivity, TS).

Reduction of NO emission by biochar and/or 3,4-dimethylpyrazole phosphate (DMPP) is closely linked to soil ammonia oxidizing bacteria and nosZI-NO reducer populations.

Biochar has been demonstrated to reduce nitrous oxide (NO) emissions from soils, but its effect is highly soil-dependent. In particular, in soils with strong nitrification potential, biochar addition may increase NO emissions. Thus, in soils with strong nitrification potential, the combination of biochar with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) may be more effective in reducing NO emissions than biochar alone.

Effect of land use and soil organic matter quality on the structure and function of microbial communities in pastoral soils: Implications for disease suppression.

Cropping soils vary in extent of natural suppression of soil-borne plant diseases. However, it is unknown whether similar variation occurs across pastoral agricultural systems. We examined soil microbial community properties known to be associated with disease suppression across 50 pastoral fields varying in management intensity.

Nitrous oxide emission and denitrifier communities in drip-irrigated calcareous soil as affected by chemical and organic fertilizers.

The effects of consecutive application of chemical fertilizer with or without organic fertilizer on soil NO emissions and denitrifying community structure in a drip-irrigated field were determined. The four fertilizer treatments were (i) unfertilized, (ii) chemical fertilizer, (iii) 60% chemical fertilizer plus cattle manure, and (iv) 60% chemical fertilizer plus biofertilizer. The treatments with organic amendments (i.

Geogenic Factors as Drivers of Microbial Community Diversity in Soils Overlying Polymetallic Deposits.

This study shows that the geogenic factors landform, lithology, and underlying mineral deposits (expressed by elevated metal concentrations in overlying soils) are key drivers of microbial community diversity in naturally metal-rich Australian soils with different land uses, i.e., agriculture versus natural bushland.

Effects of climate change on the delivery of soil-mediated ecosystem services within the primary sector in temperate ecosystems: a review and New Zealand case study.

Future human well-being under climate change depends on the ongoing delivery of food, fibre and wood from the land-based primary sector. The ability to deliver these provisioning services depends on soil-based ecosystem services (e.g.

Links between sulphur oxidation and sulphur-oxidising bacteria abundance and diversity in soil microcosms based on soxB functional gene analysis.

Sulphur-oxidising bacteria (SOB) play a key role in the biogeochemical cycling of sulphur in soil ecosystems. However, the ecology of SOB is poorly understood, and there is little knowledge about the taxa capable of sulphur oxidation, their distribution, habitat preferences and ecophysiology. Furthermore, as yet there are no conclusive links between SOB community size or structure and rates of sulphur oxidation.

Influence of geogenic factors on microbial communities in metallogenic Australian soils.

Links between microbial community assemblages and geogenic factors were assessed in 187 soil samples collected from four metal-rich provinces across Australia. Field-fresh soils and soils incubated with soluble Au(III) complexes were analysed using three-domain multiplex-terminal restriction fragment length polymorphism, and phylogenetic (PhyloChip) and functional (GeoChip) microarrays. Geogenic factors of soils were determined using lithological-, geomorphological- and soil-mapping combined with analyses of 51 geochemical parameters.

Bacterial communities associated with a mineral weathering profile at a sulphidic mine tailings dump in arid Western Australia.

We investigated bacterial community assemblages and functions down a hill slope contaminated by tailings from a volcanogenic massive sulphide mine in arid Western Australia. Weathering of waste rock, high in S and Fe, had resulted in a varying elemental dispersal down a face of the tailings hill. Bacterial community assemblage, characterised by PCR-DGGE fingerprinting, was significantly associated with electrical conductivity (E.

Extent of copper tolerance and consequences for functional stability of the ammonia-oxidizing community in long-term copper-contaminated soils.

Adaptation of soil microbial communities to elevated copper (Cu) concentrations has been well documented. However, effects of long-term Cu exposure on adaptation responses associated with functional stability and structural composition within the nitrifying community are still unknown. Soils were sampled in three field sites (Denmark, Thailand, and Australia) where Cu gradients had been established from 3 to 80 years prior to sampling.

The abundance of microbial functional genes in grassy woodlands is influenced more by soil nutrient enrichment than by recent weed invasion or livestock exclusion.

A diverse soil microbial community is involved in nitrogen cycling, and these microbes can be affected by land management practices and weed invasion. We surveyed 20 woodlands with a history of livestock grazing, with livestock recently excluded from 10 sites. We investigated whether soil nutrients were lower when grazing was excluded and higher when exotic grasses dominated the understory.

Bacteria, not archaea, restore nitrification in a zinc-contaminated soil.

Biological ammonia oxidation had long been thought to be mediated solely by discrete clades of beta- and gamma-proteobacteria (ammonia-oxidizing bacteria; AOB). However, ammonia-oxidizing Crenarchaeota (ammonia-oxidizing archaea; AOA) have recently been identified and proposed to be the dominant agents of ammonia oxidation in soils. Nevertheless, the dynamics of AOB versus AOA, and their relative contribution to soil ammonia oxidation and ecosystem functioning on stress and environmental perturbation, remain unknown.

The effect of bacteria on the sensitivity of microalgae to copper in laboratory bioassays.

Although single-species laboratory toxicity tests with microalgae are sensitive and highly reproducible, they lack environmental realism. Interactions between algae and their associated bacteria, either in the plankton or in biofilms, may alter algal sensitivity to contaminants, which are not mimicked in laboratory toxicity tests. This study investigated the effects of simple algal-bacterial relationships on the sensitivity of laboratory-cultured algae to copper using 72-h algal growth-rate inhibition bioassays.

Effect of wastewater treatment plant effluent on microbial function and community structure in the sediment of a freshwater stream with variable seasonal flow.

We investigated the effects of wastewater treatment plant (WWTP) discharge on the ecology of bacterial communities in the sediment of a small, low-gradient stream in South Australia. The quantification of genes involved in the biogeochemical cycling of carbon and nitrogen was used to assess potential impacts on ecosystem functions. The effects of disturbance on bacterial community structure were assessed by PCR-denaturing gradient gel electrophoresis of 16S rRNA genes, and clone library analysis was used to phylogenetically characterize significant shifts.

The effects of stubble retention and nitrogen application on soil microbial community structure and functional gene abundance under irrigated maize.

The effects of agronomic management practices on the soil microbial community were investigated in a maize production system in New South Wales, Australia. The site has been intensively studied to measure the impact of stubble management and N-fertilizer application on greenhouse gas emissions (CO(2) and N(2)O), N-cycling, pathology, soil structure and yield. As all of these endpoints can be regulated by microbial processes, the microbiology of the system was examined.