Your search found 14 records
1 Jouquet, P.; Bernard-Reversat, F.; Bottinelli, N.; Orange, Didier; Rouland-Lefevre, C.; Toan, Tran Duc; Podwojewski, Pascal. 2006. Influence of change in land use and earthworm activities on carbon and nitrogen dynamics in a steepland ecosystem in Northern Vietnam. Biology and Fertility of Soils, 44(1): 69-77.
Soil management ; Agroecosystems ; Erosion ; Soil properties ; Earthworms ; Land use ; Soil fertility ; Nitrogen / Vietnam
(Location: IWMI-HQ Call no: IWMI 631.4 G784 JOU Record No: H039293)
2 Clement, Floriane; Amezaga, Jaime M.; Orange, Didier; Toan, Tran Duc. 2007. The impact of government policies on land use in northern Vietnam: an institutional approach for understanding farmer decisions. Colombo, Sri Lanka: International Water Management Institute (IWMI). 21p. (IWMI Research Report 112) [doi: https://doi.org/10.3910/2009.112]
Land use ; Public policy ; Reforestation ; Farmers ; Decision making ; Land management ; Shifting cultivation ; Villages / Vietnam
(Location: IWMI HQ Call no: IWMI 333.7313 G784 CLE Record No: H040277)
(881KB)
This report identifies the driving forces for reforestation in three villages of Northern Vietnam. Using an institutional analysis focused on the rules governing upland access and use, the authors assess the relative impact of state policies (reforestation programs and forestland allocation) on land use change. Findings show that the latter are indirectly responsible for reforestation, but not because of the incentives they provided. Instead, they disrupted the local rules governing annual crop cultivation and grazing activities leading to the end of annual cropping. Tree plantation was chosen by farmers as a last resort option. Lessons learned highlight the importance of local level studies and collective rules for land management.
3 Orange, Didier; Podwojewski, Pascal; Toan, Tran Duc; Van Rinh, Pham; Phai, Do Duy; Phuong, Nguten Duy. 2007. Impact of land-use on bed load transported by rivers in the Dong Cao Watershed, North Vietnam. Water Figures Asia: news of IWMI’s work in Asia, 1: 4-5.
(Location: IWMI HQ Call no: IWMI 630.7 G000 IWM Record No: H040803)
4 Jouquet, P.; Bottinelli, N.; Mathieu, J.; Orange, Didier; Podwojewski, Pascal; Henry des Tureaux, Thierry; Toan, Tran Duc. 2007. Impact of land-use change on earthworm diversity and activity: the consequences for soil fertility and soil erosion. In 2nd International Conference on Sustainable Sloping Lands and Watershed Management, LuangPhrabang, Laos, 12-15 December 2006. pp.127-138.
Land use ; Earthworms ; Soil fertility ; Soil properties ; Erosion ; Runoff ; Infiltration ; Cassava ; Farming systems ; Eucalyptus / Vietnam / Dong Cao Watershed
(Location: IWMI HQ Call no: IWMI 631.4 G784 JOU Record No: H040804)
http://www.nafri.org.la/documents/SSLWM/SSLWMpapers/chapter2/ch2_02_jouguet.pdf
https://vlibrary.iwmi.org/pdf/H040804.pdf
https://vlibrary.iwmi.org/pdf/H040804.pdf
Earthworms are considered useful indicators for monitoring different farming practices, landscape structures and transformations because they respond quickly to land-use change. Many articles have been written on the effects of soil macrofauna (termites and earthworms) on soil properties and the functioning of ecosystems. These soil animals are usually considered to have a positive influence on soil organic matter decomposition and nutrient cycling. They increase the concentration of nutrients in their biogenic structures (casts, sheetings, nests, galleries etc.) and promote the growth and diversity of plants. However, there is a lack of data concerning their impact on tropical ecosystems with steep slopes. This study is part of the Management of Soil Erosion Consortium (MSEC) project, which examines the effects of land-use changes on soil erosion on a southeast Asian regional scale. The aim of the study was to evaluate the recovery potential of earthworms and their effects on soil conservation in areas where cassava crops were replaced by four different types of vegetation cover. It was conducted in an experimental watershed in Hoa Binh province, a mountainous area of northern Vietnam. Results showed that landuse change affects earthworm diversity and that this has significant consequences in terms of soil fertility, water infiltration and soil erosion. In plots planted with eucalyptus, large amounts of plant litter and probably higher soil moisture levels favour Pheretima leucocirca activity. These worms produce surface casts, which then became free aggregates, and galleries which are sometimes open at the surface. Casts, galleries and aggregates increase water infiltration and thus reduced water runoff and soil erosion. Cassava, fallow and fodder, however, favour Metaphire californica worms, which do not make casts. A soil crust is formed, which leads to a decrease in water infiltration and increased soil erosion. The data clearly shows that biological parameters such as earthworm diversity and activity must not be neglected in studies of the determinants of soil erosion after land-use change. Upland land-use systems with vegetation that produces lots of ground litter may help encourage beneficial worm species (such as Ph. leucocirca) and thus help reduce soil erosion and accelerate restoration of degraded land.
5 Phai, D. D.; Orange, Didier; Migraine, J. B.; Toan, Tran Duc; Vinh, N. C. 2007. Applying GIS-assisted modelling to predict soil erosion for a small agricultural watershed within sloping lands in Northern Vietnam. Paper presented at the 2nd International Conference on “Sustainable Sloping Lands and Watershed Management”, LuangPhrabang, Laos. 12-15 December 2006. pp. 212-228.
(Location: IWMI HQ Call no: IWMI 631.45 G784 PHA Record No: H040813)
GIS-assisted distributed modelling is particularly useful for supplying information to decision-makers regarding land-use, water management and environmental protection. This study deals with the prediction of soil losses by a simple distributed and GIS-assisted model within a small experimental agricultural watershed on sloping lands in northern Vietnam (<1 km2). The Predict and Localise Erosion and Runoff (PLER) model predicts the spatial and temporal distribution of soil erosion rates; thus it can be used to identify erosion hot spots in a watershed. The model has been built specifically to take into account steep slopes. It is a conceptual erosion model on a physical base. Indeed, the model imitates soil erosion as a dynamic process which includes three phases: i) detachment, ii) transport and iii) deposition. In this study the PLER model was used for two complete years, 2003 and 2004. The disparity for the soil erosion quantity between the experiment and the run model was 5.1% in 2003 and 4.9% in 2004, even though these two years had a very different annual amount of rain. Indeed, 40% of the rainfall events were of a strong intensity (>75 mm hr-1) in 2003 as apposed to only 4% in 2004. The amount of rainfall in 2003 and 2004 was 1,583 mm and 1,353 mm, respectively. The PLER model took into account this discrepancy in the rainfall characteristics between the two years. Between April to September, the disparity fluctuates between just 4.7%-5.3%. The maps drawn by the PLER model underline that the erosion process occurs mainly at the top of the landscape and highlights a different behaviour for detachability and soil erosion between the western and the eastern parts of the studied watershed.
6 Jouquet, P.; Podwojewski, Pascal; Bottinelli, N.; Mathieu, J.; Martinez, M. R.; Orange, Didier; Toan, Tran Duc; Valentin, Christian. 2008. Above-ground earthworm casts affect water runoff and soil erosion in northern Vietnam. Catena, 74(1): 13-21.
(Location: IWMI HQ Call no: IWMI 631.45 G784 PAS Record No: H040814)
7 Orange, Didier; Toan, Tran Duc; Salgado, P.; Phuong, N. D.; Van Thiet, N.; Clement, Floriane; Binh, L. H. 2008. Different interests, common concerns and shared benefits. LEISA Magazine, 24(2):12-13.
Soil management ; Erosion ; Control methods ; Villages ; Land management ; Sloping land ; Decision making ; Farmer participation ; Farming systems ; Crop production ; Fodder ; Development projects / Vietnam / Hoa Binh Province
(Location: IWMI HQ Call no: IWMI 631.45 G784 ORA Record No: H041495)
http://www.leisa.info/index.php?url=getblob.php&o_id=209097&a_id=211&a_seq=0
https://vlibrary.iwmi.org/pdf/H041495.pdf
https://vlibrary.iwmi.org/pdf/H041495.pdf
Getting farmers to adopt new technologies to address soil erosion and fertility problems is not easy. In Vietnam, a multidisciplinary research project to improve soil management in traditional mountainous agricultural farming systems managed to attract farmers’ interest and stop soil erosion. This success stems from encouraging farmers, extensionists and researchers to jointly define and implement the project. Their different aims could be followed simultaneously: scientific results for researchers, better agricultural practice for extension workers, and economic success and free choice for farmers.
8 Valentin, Christian; Agus, F.; Alamban, R.; Boosaner, A.; Bricquet, J. P.; Chaplot, V.; de Guzman, T.; de Rouw, A.; Janeau, J. L.; Orange, Didier; Phachomphonh, K.; Phai, Do Duy; Podwojewski, P.; Ribolzi, O.; Silvera, N.; Subagyono, K.; Thiebaux, Jean-Pierre; Toan, Tran Duc; Vadari, T. 2008. Runoff and sediment losses from 27 upland catchments in Southeast Asia: impact of rapid land use changes and conservation practices. Agriculture, Ecosystems and Environment, 128:225-238.
Runoff ; Sedimentation ; Catchment areas ; Land use ; Erosion ; Upland rice ; Maize ; Cassava ; Shifting cultivation ; Farming systems ; Soil conservation ; Sloping land / Southeast Asia / Indonesia / Laos / Philippines / Thailand / Vietnam
(Location: IWMI HQ Call no: IWMI 631.45 G800 VAL Record No: H041507)
9 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.
10 Bottinelli, N.; Henry des Tureaux, Thierry; Hallaire, V.; Mathieu, J.; Benard, Y.; Toan, Tran Duc; Jouquet, Pascal. 2010. Earthworms accelerate soil porosity turnover under watering conditions. Geoderma, 156(1-2):43-47. [doi: https://doi.org/10.1016/j.geoderma.2010.01.006]
(Location: IWMI HQ Call no: e-copy only Record No: H042815)
(0.56 MB)
Endogeic earthworms significantly modify soil aggregation and porosity, which in turn control water flow in soil. This study aimed to determine how the earthworm casting activity influences soil porosity and its dynamics. The main hypothesis was that the deposition of belowground water-stable casts increases soil porosity and its water stability. First we quantified cast production by the endogeic earthworm species Metaphire posthuma under laboratory conditions for 15 days. Secondly, casts and the bulk soil were analysed for structural stability to water and were packed in soil and subjected to wetting under various conditions and energy levels. The shape and size of pores were measured by image analysis. Almost all casts (98%) were produced belowground. M. posthuma produced approximately five times its own weight per day. Casts were depleted in C and were more easily disaggregated by water than the bulk soil. Although casts initially led to larger soil porosity (on average 50%), their structure was unstable. As a consequence, water inputs led to a faster decrease in soil porosity in the presence of casts. Large pores in between casts were rapidly replaced by small elongated and rounded pores. These results suggest that cast lifespan and associated porosity are of primary importance in the regulation of soil porosity turnover and the ecological functions that are under its control. Our findings suggest that in the field, the low stability of casts is likely to lead to a rapid compaction of the soil after rainfall events. However, high levels of cast production may prevent soil porosity from being broken down. Soil structural porosity thus depends on the balance between the production and degradation of casts. Improvements to the soil structure will occur when the former predominates.
11 Jouquet, Pascal; Henry des Tureaux, Thierry; Mathieu, J.; Doan Thu, Thuy; Toan, Tran Duc; Orange, Didier. 2010. Utilization of Near Infrared Reflectance Spectroscopy (NIRS) to quantify the impact of earthworms on soil and carbon erosion in steep slope ecosystem: a study case in northern Vietnam. Catena, 81(2):113-116. [doi: https://doi.org/10.1016/j.catena.2010.01.010]
(Location: IWMI HQ Call no: e-copy only Record No: H042814)
(0.65 MB)
This work focuses on a new approach to quantify the effects of above-ground earthworm's activity on soil erosion in steep slope ecosystems such as in Northern Vietnam. In these areas and in many others in the world, soil erosion becomes a major issue while the factors that determine it are still misunderstood. Earthworm's activity is believed to influence soil erosion rate, but we are still unable to precisely quantify their contribution to soil erosion. In this study, we used Near Infrared Reflectance Spectroscopy (NIRS) to quantify the proportion of soil aggregate in eroded soil coming from earthworm activity. This was done by generating NIRS signatures corresponding to different soil surface aggregates (above-ground soil casts produced by earthworms vs. surrounding topsoil). In order to test the proposed approach, we compared the NIRS-signature of eroded soil sediments to those of earthworms' casts and of the surrounding soils. Our results strongly supported that NIRS spectra might be used as “fingerprints” to identify the origin of soil aggregates. Although earthworms are generally assumed to play a favorable role in promoting soil fertility and ecosystem services, this method shows that cast aggregates constitute about 36 and 77% of sediments in two tropical plantations, Paspalum atratumand Panicum maximum plantations, respectively. In light with these results, we estimated that earthworms led to an annual loss of 3.3 and 15.8 kg of carbon ha-1 yr-1, respectively in P. atratum and P. maximum agroecosystems.
12 Minh, L. T. N.; Orange, Didier; Anh, L. L.; Linh, T. T. M.; Toan, Tran Duc. 2007. Su bien doi hang nam cua chat ran lo lung va chat luong nuoc tai vung cua song dong bang chau tho song hong. In Vietnamese. [Annual evolution of suspended matter flows and the quality of water of the Red River at the entry of its delta.]. Vietnamese Scientific Journal, 2:94-97.
(Location: IWMI HQ Call no: e-copy only Record No: H043008)
(1.19 MB)
13 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.
14 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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