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| Christensen, Soren; Bjornlund, Lisa; Vestergård, Mette. |
| Quantification of the organic carbon released from plant roots is a challenge. These compounds of rhizodeposition are quickly transformed into CO2 and eventually bacterial biomass to be consumed by bacterivores (protozoa and nematodes). Microbes stimulate rhizodeposition several-fold so assays under sterile conditions give an unrealistic value. Quantifying bacterial production from H-3-thymidine incorporation falls short in the rhizosphere and the use of isotopes does not allow clear distinction between labeled CO2 released from roots or microbes. We reduced rhizodeposition in 3-5 week old barley with a 2 week leaf aphid attack and found that biomass of bacterivores but not bacteria in the rhizosphere correlated with plant-induced respiration activity... |
| Tipo: Journal paper |
Palavras-chave: "Organics" in general; Soil. |
| Ano: 2007 |
URL: http://orgprints.org/16084/2/16084.pdf |
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| Christensen, Soren; Alphei, Jörg; Vestergård, Mette; Vestergaard, Peter. |
| This paper deals with migration of nematodes along nutrient gradients in soil. Portions of barley straw and green vetch leaves were mixed with soil and buried at 6, 12, 18, and 50mm distance from each other in soil. During the following 12 weeks respiration activity, microbial (SIR) biomass, nitrogen limitation of respiration activity in soil slurries all indicated that nitrogen was transferred in the soil from the nutrient rich vetch to the nutrient poor barley at least during the first 3 weeks of the experiment. Twelve out of 39 taxonomic groups of nematodes showed different growth in the two plant material-soil mixtures. Only one of these taxonomic groups (long rhabditid larvae) suggested that migration could have contributed to population development;... |
| Tipo: Journal paper |
Palavras-chave: "Organics" in general; Soil. |
| Ano: 2007 |
URL: http://orgprints.org/16085/2/16085.pdf |
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| de Vries, Franciska T.; Liiri, M.E.; Bjørnlund, Lisa; Bowker, M.A.; Christensen, Soren; Setälä, Heikki; Bardgett, Richard. |
| Soils deliver several ecosystem services including carbon sequestration and nutrient cycling, which are of central importance to climate mitigation and sustainable food production. Soil biota play an important role in carbon and nitrogen cycling, and, although the effects of land use on soil food webs are well documented, the consequences for their resistance and resilience to climate change are not known. We compared the resistance and resilience to drought — which is predicted to increase under climate change 2,7 — of soil food webs of two common land-use systems: intensively managed wheat with a bacterial-based soil food web and extensively managed grassland with a fungal-based soil food web. We found that the fungal-based food web, and the processes of... |
| Tipo: Journal paper |
Palavras-chave: Soil biology. |
| Ano: 2012 |
URL: http://orgprints.org/20882/1/20882.pdf |
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