11 results on '"De Neve, Stefaan"'
Search Results
2. Composition of Organic Matter in Sandy Relict and Cultivated Heathlands as Examined by Pyrolysis-Field Ionization MS
- Author
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Sleutel, Steven, Leinweber, Peter, Begum, Shamim Ara, Kader, Mohammed Abdul, Van Oostveldt, Patrick, and De Neve, Stefaan
- Published
- 2008
- Full Text
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3. EFFECT OF CULTIVATION SYSTEMS ON THE DISTRIBUTION OF SOIL ORGANIC MATTER IN DIFFERENT FRACTIONS
- Author
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HUISZ, Andrea, SLEUTEL, Steven, TÓTH, Tibor, HOFMAN, Georges, De NEVE, Stefaan, and NÉMETH, Tamás
- Published
- 2006
4. Four decades of post-agricultural forest development have caused major redistributions of soil phosphorus fractions
- Author
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De Schrijver, An, Vesterdal, Lars, Hansen, Karin, De Frenne, Pieter, Augusto, Laurent, Achat, David Ludovick, Staelens, Jeroen, Baeten, Lander, De Keersmaeker, Luc, De Neve, Stefaan, and Verheyen, Kris
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- 2012
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5. Interactive effect of soil pore network structure and substrate quality on soil CO2 production: a combined X-ray CT incubation experiment
- Author
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Sleutel, Steven, Bouckaert, Liesbeth, Van Loo, Denis, Van Hoorebeke, Luc, De Neve, Stefaan, and Cnudde, Veerle
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Soil ,Earth and Environmental Sciences ,soil organic matter ,pore network ,soil aggregate - Abstract
The role of soil structure in organic matter (OM) stabilization has been primarily investigated through physical fractionation studies operative at the scale of aggregates and smaller organo-mineral particles. By narrowing down soil structure to an arrangement of mineral and organic particles, the majority of studies did not explore the spatial organization of the soil pore network, the actual habitat of microorganisms. In a lab experiment we incubated a sandy loam soil (with application of ground grass or sawdust) in 18 small aluminum rings (Ø 1 cm, h 1 cm). Bulk density was adjusted to 1.1 or 1.3 Mg m-3 (compaction) and 6 rings were filled at a coarser Coarse Sand:Fine Sand:Silt+Clay ratio.
- Published
- 2013
6. Limited short-term effect of compost and reduced tillage on N dynamics in a vegetable cropping system.
- Author
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Willekens, Koen, Vandecasteele, Bart, and De Neve, Stefaan
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COMPOSTING , *NITROGEN fertilizers , *TILLAGE , *CROPPING systems , *ORGANIC compounds , *SOIL quality , *HORTICULTURE , *CARROT growing - Abstract
Judicious management of organic matter supply and tillage practice is crucial for sustaining soil quality in horticulture. We have studied whether N fertilization of vegetable crops should be adapted in the short term when soil management changes to include compost application and reduced tillage as soil quality improving factors. The experimental setup was a multiyear field trial on a sandy loam soil with a vegetable crop rotation. Soil tillage in spring was either conventional (moldboard plough) or reduced, non-inversion tillage (with a specially designed chisel plough). Starting in 2008, farm compost was applied each autumn at three rates: 0, 15 and 45 Mg per hectare. The three-year crop rotation (2009–2011) consisted of broccoli ( Brassica oleracea , var. Italica Group), carrots ( Daucus carota ) and leek ( Allium porrum ). Small but significant differences in N dynamics were found between treatments. Broccoli had a higher N uptake and biomass production under reduced compared to conventional tillage. In accordance with this, the apparent net N mineralization tended to be higher for reduced tillage compared to conventional tillage. In contrast, for leek, N uptake did not differ between tillage practices despite a higher apparent net N mineralization under conventional tillage. A tendency for a higher biomass production under conventional tillage was in line with a tendency for a higher amount of residual soil mineral N that might have increased the risk of N losses. In the carrot crop, a higher amount of mineral N under conventional tillage did not increase root yield. Compost application maintained soil organic matter content and did not result in a higher amount of residual soil mineral N. Only in the carrot growing season, compost application increased soil mineral N content to a limited extent. The small short-term changes in overall N availability observed between treatments do not necessitate changes in N fertilization strategy or additional precautions regarding residual soil mineral N. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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7. C mineralization and microbial activity in four biochar field experiments several years after incorporation.
- Author
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Ameloot, Nele, Sleutel, Steven, Case, Sean D. C., Alberti, Giorgio, McNamara, Niall P., Zavalloni, Costanza, Vervisch, Bram, Vedove, Gemini delle, and De Neve, Stefaan
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BIOCHAR , *BIOMINERALIZATION , *SOIL microbial ecology , *SOIL biology , *DEHYDROGENASES , *BIOMASS , *GLUCOSIDASES - Abstract
Most studies looking into the effect of amendment of biochar on soil microbial functioning employ short-term laboratory studies and probably describe relatively transient phenomena. Multi-year experiments, spanning beyond initial degradation of biologically labile biochar constituents, on the other hand are more scarce, although these are much needed to establish the medium-term effect of biochar on soil organisms. In the present study, soil was sampled from biochar-amended and control plots of four biochar field trials at Lincoln (UK), Rivignano, Rocca Bernarda and Beano in Italy. Air-dried pre-incubated soil samples were incubated at 15 °C for 8-9 weeks to follow-up carbon dioxide (CO2) emissions. We then determined soil β-glucosidase and dehydrogenase enzyme activity, and used PLFA analysis to quantify the total soil microbial biomass and community structure. The analysis indicated that soil microbial activity was either not affected or inhibited to different extents in the biochar-amended plots. At Lincoln, with the highest application rate (49 t ha−1), an overall inhibition of all investigated measures of microbial activity, a lower sum of extracted PLFAs and lower fungal abundance were observed. On the other end at Beano, depth dispersion of biochar by deep tillage and a lower application rate (20 t ha−1) probably explain the absence of any significant effect on microbial activity in that experiment. At Rivignano and Rocca Bernarda, dehydrogenase activity was lower in the biochar amended soil and C-mineralization was lower as well for Rivignano. Interestingly, however, β-glucosidase activity and the sum of extracted PLFAs was not affected by biochar treatment. Several mechanisms could reconcile the different effect of biochar application on overall microbial activity on the one hand and microbial abundance and rate of cellulose degradation on the other. Biochar amendment led to a lowered or equal soil microbial activity and abundance in most field sites. In contrast to many short-term laboratory studies, it therefore seems unlikely that biochar would still function as a substrate 1-4 years after incorporation in the field. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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8. Contrast agents for soil investigation with X-ray computed tomography.
- Author
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Van Loo, Denis, Bouckaert, Liesbeth, Leroux, Olivier, Pauwels, Elin, Dierick, Manuel, Van Hoorebeke, Luc, Cnudde, Veerle, De Neve, Stefaan, and Sleutel, Steven
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COMPUTED tomography , *SOIL microbiology , *HUMUS , *SOIL porosity , *NITRATES , *SOIL composition , *SOIL mineralogy - Abstract
Abstract: The majority of microbial mediated soil processes depend on availability of organic matter (OM), water and air. Because of its ability to visualize the 3D architecture of soil non-destructively, X-ray computed tomography (CT) is becoming a widespread tool for studying soil pore network structure. However, phase determination of pore space, soil OM, soil mineral matter (MM) and water is often limited even with the latest technological and software advances, allowing high resolution and better quality imaging. Contrast agents commonly used in histology enable enhancement of X-ray attenuation of targeted structures or compounds. Here we report on the first systematic investigation of the use of such X-ray contrast agents for soil research. An evaluation procedure as well as a method to apply the agents to soil samples was developed and applied on reference soil samples. The effectiveness and selectivity of the contrast agents was evaluated for soil organic matter (SOM), MM and water. Several products were found to selectively increase the attenuation of water or SOM. The four agents with the best OM-staining capabilities (phosphomolybdenic acid (PMA), silver nitrate, lead nitrate and lead acetate) were further tested on an OM-MM mixture and all showed an increased of the SOM attenuation coefficient above the MM values. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
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9. Shifts in soil organic matter composition following treatment with sodium hypochlorite and hydrofluoric acid
- Author
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Sleutel, Steven, Leinweber, Peter, Ara Begum, Shamim, Kader, Mohammed Abdul, and De Neve, Stefaan
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ORGANIC compound content of soils , *SOIL composition , *SODIUM hypochlorite , *HYDROFLUORIC acid , *FIELD ionization mass spectrometry , *SOIL chemistry , *HEATHLANDS , *CHEMICAL decomposition - Abstract
Abstract: A renewed interest in chemical fractionation of soil organic matter (SOM) originates from the premise that it enables to isolate labile SOM from SOM protected through mineral binding and recalcitrant SOM. Both selective removal of labile non-bound SOM through oxidation or hydrolysis as well as selective removal of minerals and attached SOM are often applied. Molecular-level SOM characterization by means of temperature resolved Pyrolysis-Field Ionization Mass Spectroscopy analysis (Py-FIMS) was used here as an approach to obtain insight into the fate of SOM upon wet chemical treatment with regard to composition and thermal stability. The applied sequential chemical treatment with 6% NaOCl and 10% HF yielded similar sizes in stable SOM fractions between sandy semi-native heathland and cultivated cropland soil pairs (i.e. NaOCl resistant OC: 12.3–15.0 g C kg−1 and NaOCl+HF resistant OC: 2.6–5.3 g C kg−1). Py-FIMS spectra of bulk SOM in both heathland–cropland soil pairs were dominated by signals assigned to lipids, alkylaromatics and sterols. Difference spectra and thermograms showed selective loss of signals from sterols, lignin dimers and thermolabile lipids. This matches advancing SOM decomposition as derived from previously reported gradients in SOM composition as decomposition proceeds from plant material over particulate organic matter (OM) to SOM in silt and clay particle sizes. However, increased ion intensity attributed to carbohydrates, peptides and short-chained lipids after NaOCl treatment indicates that biologically labile SOM components were also enriched, and they may possibly have been protected through mineral binding or encapsulation in macromolecular OM structures. Subsequent HF treatment yielded increased volatilization in the thermostable region for mass signals tentatively assigned to phenols and lignin monomers and of heterocyclic N-containing compounds and thermostable alkylaromatics. The resistance to chemical treatment of the latter two components matches with their hypothesized structural function in macro OM molecules. However, even for the sites investigated here, with a very similar soil texture, climate, land-use, drainage and contents of pedogenic oxides, contrasting and not readily explainable results were found for other SOM constituents. Therefore, chemical fractionations seem to yield very site specific and less distinct patterns and this study demonstrated that derivation of useful information regarding SOM stabilization mechanisms from such experiments is by no means straightforward. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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10. Nitrogen dynamics in relation to soil management and soil quality in field vegetable cropping systems
- Author
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Willekens, Koen, De Neve, Stefaan, and Vandecasteele, Bart
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vegetables ,compost ,Earth and Environmental Sciences ,soil organic matter ,nitrogen dynamics ,soil quality ,reduced tillage ,soil management ,green manuring ,apparent net N mineralization - Published
- 2016
11. Influence of vegetable inclusion in rice monoculture on soil organic matter quality under sub-tropical climate
- Author
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Steven Sleutel, Abdul Kader, Stefaan De Neve, Shamim Ara Begum, De Neve, Stefaan, Boehme, M, Everaarts, A, and Neeteson, J
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Agriculture and Food Sciences ,geography ,rice monoculture ,geography.geographical_feature_category ,Floodplain ,Terrace (agriculture) ,Soil organic matter ,soil organic matter quality ,food and beverages ,vegetable soil ,sub-tropical soil ,Subtropics ,Horticulture ,Silt ,complex mixtures ,Agronomy ,cropping pattern ,Soil water ,MANAGEMENT ,physical fractionation ,Environmental science ,Monoculture ,Cropping ,FRACTIONS - Abstract
Soil organic matter (SOM) quality and iits decomposibility is influenced by cropping pattern. However, little is known on this matter, particularly so far rice monoculture or comination of vegetables with rice culture. Therefore, four pairs of fields having vegetable-rice and rice-rice cropping pattern were selected from four different locations in Bangladesh, covering floodplain and terrace soils. Soils were first physically fractionated into particulate organic matter (POM) and silt and clay sized OM. The silt and clay sized OM was further chemically fractionated by oxidation with 6% NaOCl to isolate an oxidation-resistant OM fraction, followed by extraction of mineral bound OM with 10% HF (HF-res OM). The results show that there is a small increase in POM in vegetable compared with rice soils. Among the chemical treatments, NaOCl oxidized the largest amount of OC and N from the silt and clay fractions of vegetable soils. The silt and clay N in vegetable soil was found to be more susceptible to NaOCl treatment compared with OC. Both the HF-extracted (HF-ex) and HF-res OM fractions were found to be lower in vegetable soils compared with rice soils. Results from both physical and chemical fraction of SOM suggest that SOM accumulated in vegetable-rice cropping pattern are more labile than the solely rice based cropping pattern and prone to decompose quickly in any change of land use.
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