Your search found 7 records
1 Rumpel, C.; Chaplot, V.; Planchon, O.; Bernadou, J.; Valentin, Christian; Mariotti, A. 2006. Preferential erosion of black carbon on steep slopes with slash and burn agriculture. Catena, 65(1):30-40.
(Location: IWMI-HQ Call no: IWMI 631.45 G708 RUM Record No: H038783)
2 Rumpel, C.; Gonzalez-Perez, J. A.; Bardoux, G.; Largeau, C.; Gonzalez-Vila, F. J.; Valentin, Christian. 2007. Composition and reactivity of morphologically distinct charred materials left after slash-and- burn practices in agricultural tropical soils. Organic Geochemistry, 38:911–920.
Forest soils ; Nitrogen ; Carbon ; Shifting cultivation ; Forest fires ; Wildfires / Laos / Houay Pano watershed
(Location: IWMI HQ Call no: IWMI 630 G708 RUM Record No: H040753)
The composition of black carbon (BC) was studied up to now using laboratory experiments, which often fail to reproduce conditions occurring in natural fires. We sampled plant material and two BC fractions produced during slash and burn agriculture from two adjacent sites. A coarse fraction (CF), most probably derived from twigs and stems, was differentiated from lighter, fluffy fine material (FF). The samples were analysed for elemental and isotopic composition and their reactivity using acid hydrolysis and acid dichromate oxidation. The chemical composition of the samples was studied by 13C CPMAS NMR spectroscopy and analytical pyrolysis. The lignin content of the samples was determined after CuO oxidation. The two BC fractions were higher in carbon than the plant material. On an ash-free basis the CF and FF sampled from the two different sites had remarkably similar elemental contents. Stable isotope ratios of carbon showed enrichment or depletion depending on the morphological fraction under C3 vegetation. The ratios tended to be depleted in 13C with regards to the plant material in both fractions for samples taken under C4 vegetation. The reactivity of BC towards dichromate oxidation and acid hydrolysis was lower for CF compared to FF. 13C CPMAS NMR spectroscopy showed that BC fractions were aromatic but could also show substantial contribution from alkyl and O-alkyl C. Analytical pyrolysis and CuO oxidation indicated that part of the lignin backbone was remaining in all BC
3 Rumpel, C.; Chaplot, V.; Chabbi, A.; Largeau, C.; Valentin, Christian. 2008. Stabilisation of HF soluble and HCl resistant organic matter in sloping tropical soils under slash and burn agriculture. Geoderma, 145:347-354.
Sloping land ; Shifting cultivation ; Tropical soils ; Climatic soil types ; Erosion ; Soil profiles / Laos / Luang Prabang
(Location: IWMI HQ Call no: IWMI 631.4 G708 RUM Record No: H041554)
4 Jouquet, Pascal; Zangerle, A.; Rumpel, C.; Brunet, D.; Bottinelli, N.; Toan, Tran Duc. 2009. Relevance of the biogenic and physicogenic classification: a comparison of approaches to discriminate the origin of soil aggregates. European Journal of Soil Science, 60:1117-1125. [doi: https://doi.org/ 10.1111/j.1365-2389.2009.01168.x]
Soil analysis ; Biogenic amines ; Earthworms ; Soil structural units ; Soil organic matter ; Nutrient cycling in ecosystems ; Soil structure
(Location: IWMI HQ Call no: e-copy only Record No: H042643)
(0.84 MB)
Although freshly formed or unaltered biogenic aggregates are easily recognized, identifying the origin of aggregates altered by physical and biological processes remains empirical and prone to error. The aim of this study was to distinguish between biogenic (BIO) and physicogenic (PHYS) aggregates in various states of fragmentation or size classes using visual, physical and chemical characteristics. Casts produced by Amynthas khami (BIO) and surrounding soil aggregates without visible biological activity (PHYS) were left to disaggregate by natural rainfall events and then separated into five size classes of >10, 10–5, 5–2, 2–0.5 and <0.5 mm. We then analysed aggregate morphology, elemental and stable isotope composition and soil stability, and used near-infrared spectroscopy (NIRS) to determine their chemical characteristics. Although visual assessment is the method most commonly used in the field to distinguish between BIO and PHYS, our study found that the results obtained were always prone to error and that the classification was arbitrary for BIO and PHYS aggregates smaller than 5 and 2 mm in size, respectively. Soil structural stability was only useful for identifying BIO aggregates larger than 2 mm. While C content and d13C in BIO were always different from PHYS, regardless of soil aggregate size, N content and d15N were similar. NIRS was the most effective method because it clearly discriminated soil aggregates on the basis of size and origin. The NIRS characteristics of BIO were also more uniform than those of PHYS, suggesting that BIO aggregates have a simpler organization and as a consequence more homogeneous ecological functions. Thus, our findings suggest that information may be lost when only the physical aspect of aggregates is used to quantify the activity of ecosystem engineers in soil. After fragmentation, BIO aggregates become hidden and although it may be impossible to distinguish them visually from PHYS aggregates they retain some of their specific chemical characteristics.
5 Jouquet, Pascal; Plumere, Thierry; Doan Thu, T.; Rumpel, C.. 2010. The rehabilitation of tropical soils using compost and vermicompost is affected by the presence of endogeic earthworms. Applied Soil Ecology, 46:125-133. [doi: https://doi.org/10.1016/j.apsoil.2010.07.002]
(Location: IWMI HQ Call no: e-copy only Record No: H043190)
(0.34 MB)
As soil engineers, earthworms play a key role in soil organic matter turnover and ecosystem functioning. Numerous studies have shown their positive influence on plant growth and soil quality. At the same time, organic matter inputs in compost or vermicompost, produced in the presence of earthworms, are valuable soil amendments that may increase plant growth. However, whether the combination of earthworm activity and organic matter amendments can be a successful approach for soil rehabilitation remains insufficiently studied. The aim of the present study was to determine the interactions between Dichogaster bolaui , an endogeic earthworm species, and compost or vermicompost produced by Eisenia andrei , an epigeic earthworm species, in a degraded tropical soil. We assessed nutrient availability and natural vegetation recovery. Treatments with and without D. bolaui earthworms were compared. The incorporation of both types of organic matter improved soil quality (i.e., higher pH, more C and nutrients) and led to the recovery of vegetation growth (i.e., development of seedlings and higher above- and belowground biomass). Mineral nutrients, on the other hand, had no effect on vegetation development and led to more pollution of groundwater (i.e., higher concentrations of N-NH 4 +, N-NO 3 - , K and P). Although we could not draw definite conclusions about whether vermicompost had a more positive effect on plant growth than compost, this substrate improved soil chemical properties compared with compost. Dichogaster bolaui enhanced leaching of N-NH 4 + , N-NO 3 - and K when mineral nutrients were used. However overall, D. bolaui had a neutral impact on plant growth when combined with compost, but a negative effect when in combination with vermicompost inputs. In conclusion, this experiment demonstrated that organic matter amendment is an interesting alternative for the rehabilitation of tropical soils. However, negative interactions can occur between local endogeic earthworms and vermicompost.
6 Hong, Hanh Nguyen; Rumpel, C.; Henry des Tureaux, Thierry; Bardoux, G.; Billou, D.; Toan, Tran Duc; Jouquet, Pascal. 2011. How do earthworms influence organic matter quantity and quality in tropical soils? Soil Biology and Biochemistry, 43(2):223-230. [doi: https://doi.org/10.1016/j.soilbio.2010.09.033]
(Location: IWMI HQ Call no: e-copy only Record No: H043453)
(0.75 MB)
Earthworms are important regulators of soil structure and soil organic matter (SOM) dynamics; however, quantifying their influence on SOM cycling in tropical ecosystems remains little studied. Simulated rainfall was used to disrupt casts produced by Amynthas khami and their surrounding soil (control) into a range of small sized aggregates (50e250, 250e500, 500e2000 and 2000e5000 mm). To gain insight into how earthworms influence SOM biogeochemical composition in the aggregates, we carried out elemental and stable isotope analysis, and analytical pyrolysis (Py GC/MS). We also characterized their lignin component after oxidation with cupric oxide (CuO).The C content of smaller size fractions (<500 mm) in the control soil was higher than in the larger fractions. Our study therefore suggests that the aggregate hierarchy concept, which is used to understand soil aggregates and SOM dynamics in temperate soils, may not be applicable to the tropical Acrisol studied here. Earthworms modified SOM organization in soil aggregates. Although the isotope analyses were useful for highlighting SOM enrichment in the earthworm casts, aggregate fractions could not be classified according to particle size. Molecular analyses were necessary to indicate that SOM in all size fractions of casts consisted of relatively undecomposed material. Protection of the most labile SOM structures occurred in the smallest aggregate size fraction (50e250 mm). Py GC/MS showed that earthworm casts and control aggregates <2000 mm could be clearly distinguished according to the molecular properties of their SOM. Aggregates larger than 2000 mm, however, were most probably composed of all fractions and were not different. As a consequence, our results indicate that studies to determine the impact of earthworms on SOM turnover in soil are spatially dependant on the scale of observation.
7 Jouquet, Pascal; Bloquel, E.; Doan Thu, Thuy; Ricoy, M.; Orange, Didier; Rumpel, C.; Toan, Tran Duc. 2011. Do compost and vermicompost improve macronutrient retention and plant growth in degraded tropical soils? Compost Science and Utilization, 19(1):15-24.
Composts ; Vermicomposting ; Primary nutrients ; Tropical soils ; Soil degradation ; Soil fertility ; Acrisols ; Water pollution ; Plant growth / Southeast Asia / Vietnam / Dong Cao Village
(Location: IWMI HQ Call no: e-copy only Record No: H043675)
(0.89 MB)
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