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1. Fine roots and mycorrhiza often represent the largest input of carbon (C) into soils and are therefore of primary relevance to the soil C balance. Arbuscular mycorrhizal (AM) fungi have previously been found to increase litter decomposition which may lead to reduced soil C stocks, but these studies have focused on immediate decomposition of relatively high amounts of high-quality litter and may
The clover seed weevils Apion fulvipes Geoffroy, 1785 and Apion trifolii L., 1768 (Coleoptera: Apionidae) cause major losses to seed production of white clover (Trifolium repens L.) and red clover (Trifolium pratense L.), respectively. Clover is important as animal forage and an alternative to inorganic fertilizers. Because clover is mainly pollinated by bees, the use of insecticides in management
Increasing nitrogen(N) deposition due to anthropogenic activities has become a significant global change threat to N-poor terrestrial ecosystems. We compared bacterial growth and nutrients limiting bacterial growth in one of the longest running experiments on increasing N-deposition to a temperate forest, the Chronic Nitrogen Amendment Study at Harvard Forest, USA. Soil samples were collected in f
Under chronically elevated N deposition, N retention mainly occur at high soil C-to-N ratio. This may be mediated through soil microbes, such as ectomycorrhizal (EM) fungi, saprotrophic fungi and bacteria, and the aim of this study was to evaluate the relationship between soil microbes and forest floor C-to-N ratios. Soil samples from 33 Norway spruce (Picea abies (L.) H. Karst) forests in Denmark
The influence of soil pH on the phospholipid fatty acid (PLFA) composition of the microbial community was investigated along the Hoosfield acid strip, Rothamsted Research, UK - a uniform pH gradient between pH 8.3 and 4.5. The influence of soil pH on the total concentration of PLFAs was not significant, while biomass estimated using substrate induced respiration decreased by about 25%. However, th
Microbial decomposition of soil organic matter (SOM) is the source of most of the terrestrial carbon dioxide emission. Consequently, our ability to predict how climate warming will affect the global carbon (C) budget relies on our understanding of the temperature relationship and adaptability of microbial processes. We exposed soil microcosms to temperatures between 0 and 54 degrees C for 2 months
Boreal forest soils function as a terrestrial net sink in the global carbon cycle. The prevailing dogma has focused on aboveground plant litter as a principal source of soil organic matter. Using C-14 bomb-carbon modeling, we show that 50 to 70% of stored carbon in a chronosequence of boreal forested islands derives from roots and root-associated microorganisms. Fungal biomarkers indicate impaired
Foliose lichens with cyanobacterial bionts (bipartite and tripartite) form a distinct assemblage of epiphytes strongly associated with humid microclimatic conditions in inland British Columbia. Previous research showed that these cyano- and cephalolichen communities are disproportionately abundant and species-rich on conifer saplings beneath Populus compared to beneath other tree species. More rev
The effects of nitrogen (N) fertilization (0-150 kg N ha(-1) year(-1) since 1865) and pH (3.3-7.4) on fungal and bacterial growth, biomass and phospholipid fatty acid (PLFA) composition were investigated in grassland soils from the 'Park Grass Experiment', Rothamsted Research, UK. Bacterial growth decreased and fungal growth increased with lower pH, resulting in a 50-fold increase in the relative
We studied bacterial and fungal colonization of submerged plant litter, using a known Si-accumulator (Equisetum arvense), in experimental microcosms during one month. We specifically addressed the microbial decomposer role concerning biogenic silica (bSiO2) dissolution from the degrading litter. To vary the rates and level of microbial colonization, the litter was combined with a range of mineral
There is growing evidence of the importance of extramatrical mycelium (EMM) of mycorrhizal fungi in carbon (C) cycling in ecosystems. However, our understanding has until recently been mainly based on laboratory experiments, and knowledge of such basic parameters as variations in mycelial production, standing biomass and turnover as well as the regulatory mechanisms behind such variations in fores
Mycorrhizal fungi constitute a considerable sink for carbon in most ecosystems. This carbon is used for building extensive mycelial networks in the soil as well as for metabolic activity related to nutrient uptake. A number of methods have been developed recently to quantify production, standing biomass and turnover of extramatrical mycorrhizal mycelia (EMM) in the field. These methods include min
Global patterns in soil, plant, and fungal stable isotopes of N (delta N-15) show promise as integrated metrics of N cycling, particularly the activity of ectomycorrhizal (ECM) fungi. At small spatial scales, however, it remains difficult to differentiate the underlying causes of plant delta N-15 variability and this limits the application of such measurements to better understand N cycling. We co
Our aim was to examine the effect of water stress on plant growth and development of two native plant species (Tetraclinis articulata and Crithmum maritimum) and on microbial community composition and activity in the rhizosphere soil, following the addition of an organic amendment, namely sugar beet residue (SBR), and/or the inoculation with an arbuscular mycorrhizal (AM) fungus, namely Glomus mos
Soil tillage practices affect the soil microbial community in various ways, with possible consequences for nitrogen (N) losses, plant growth and soil organic carbon (C) sequestration. As microbes affect soil organic matter (SOM) dynamics largely through their activity, their impact may not be deduced from biomass measurements alone. Moreover, residual microbial tissue is thought to facilitate SOM
Secondary hole-nesting birds that do not construct nest holes themselves and hence regularly breed in nest boxes constitute important model systems for field studies in many biological disciplines with hundreds of scientists and amateurs involved. Those research groups are spread over wide geographic areas that experience considerable variation in environmental conditions, and researchers provide
While many laboratory studies have focused on the short term effects of biochar addition to soil), there have been comparatively few tracing its longer term effects in the field. This study investigated the multiyear impact of biochar on crop performance and soil quality with specific emphasis on carbon (C) and nitrogen (N) cycling over a 3 y period. Biochar was added to an agricultural field at 0
A substantial portion of the carbon (C) fixed by the trees is allocated belowground to ectomycorrhizal (EM) symbionts, but this fraction usually declines after fertilization. The aim of the present study was to estimate the effect of optimal fertilization (including all the necessary nutrients) on the growth of EM fungi in young Norway spruce forests over a three year period. In addition, the amou
The determination of the phospholipid fatty acid (PLFA) pattern of soil organisms has become one of the most commonly used methods to study microbial community structure. Here we recapitulate the background of our work applying the PLFA method to soil in the early 1990s. We also stress that although the PLFA method was, and still is, a rapid and sensitive method to detect changes in the microbial
