Your search found 18 records
1 Pierret, Alain; Doussan, C.; Capowiez, Y.; Bastardie, F.; Pages, L. 2007. New computer models of plant roots. CSA News, 52(7): 1.
(Location: IWMI HQ Call no: IWMI 631.4 G000 PIE Record No: H040873)
2 Mousques, C.; Sengsoulychanh, P.; Sengtaheuanghoung, O.; Latchackack, K.; Ribolzi, O.; Pierret, Alain. 2007. Relevance of Payments for Environmental Services (PES) for watershed management in northern Laos. Keynote address at the 2nd International WEPA Forum on Water Environmental Governance in Asia. The Water Environment Partnership in Asia (WEPA), 3-4 December 2007, in Beppu City, Oita Prefecture, Japan. 6p.
(Location: IWMI HQ Call no: IWMI 333.91 G708 MOU Record No: H041516)
(0.46 MB)
In this paper we discuss the main results of a feasibility study for the implementation of Payments for Environmental Services (PES) in a small watershed of northern Laos. The aim of the work was to assess the relevance of such a scheme as a way to control both the quality and flow of a small mountain stream. We found that the PES concept, with some adaptations, may offer interesting avenues as a means to maintain water quality through an improved control of soil erosion in the upper catchment: Willingness-To-Pay (WTP) within the sampled population was approx. USD 0.3/month/household which would be sufficient to abate the negative impact of soil erosion. At the whole catchment scale, major impediments to the immediate implementation of a PES scheme were i) the lack an unequivocal relationship between environmental services, users and providers, ii) insufficient WTP to maintain water quality along the stream through waste management and iii) absence of a critical mass of buyers. A precondition of successful implementation of PES in the area is to increase the awareness of environmental issues in the concerned communities.
3 Pierret, Alain; Doussan, C.; Pages, L.; Do, F. C.; Gonkhamdee, S.; Maeght, J. L.; Chintachao, W.; Nandris, D. 2007. Is impeded root growth related to the occurrence of rubber tree Trunk Phloem Necrosis (TPN)?: preliminary results from NE Thailand. Paper presented at IRRDB Annual Meeting, Siem Reap Cambodia, 12-16 November 2007. 10p.
(Location: IWMI HQ Call no: e-copy only Record No: H041685)
This paper presents the results of a pilot project aimed at unravelling putative links between the occurrence of Trunk Phloem Necrosis (TPN) and impeded root system development in a small rubber tree (RRIM 600) plantation of NE Thailand. To investigate as many root parameters as possible, our methodology included a wide range of techniques: destructive sampling, root mapping, rhizolocation, architectural characterisation of coarse woody roots, and electrical measurements by capacitance and earth impedance. We found that under the environmental conditions that prevail in NE Thailand, there is no relationship between most of the root parameters we measured and TPN, at least within the first meter of the soil profile. This result contrasts with observations previously made in western Africa. However, we found that at a soil depth of ~25 cm where maximum soil bulk density is generally observed, Healthy (H) trees can grow roots of significantly higher Specific Root Length (SRL) than those affected by TPN. The next phase of this work which is part of a multidisciplinary programme on TPN, will therefore focus on root morphological descriptors such as SRL and on the analysis of the deeper parts of rubber tree root systems.
4 Planchon, O.; Orange, Didier; Pierret, Alain; Boonsanner, A.; Nguyen, D. P.; Sengtaheuanghoung, O.; Valentin, Christian. 2008. Relevance and feasibility of PES to combat soil erosion and solve catchment management issues in the Mekong Region. In Humphreys, E.; Bayot, R. S.; van Brakel, M.; Gichuki, F.; Svendsen, M.; Wester, P.; Huber-Lee, A.; Cook, S. Douthwaite, B.; Hoanh, Chu Thai; Johnson, N.; Nguyen-Khoa, Sophie; Vidal, A.; MacIntyre, I.; MacIntyre, R. (Eds.). Fighting poverty through sustainable water use: proceedings of the CGIAR Challenge Program on Water and Food, 2nd International Forum on Water and Food, Addis Ababa, Ethiopia, 10-14 November 2008. Vol.3. Water benefits sharing for poverty alleviation and conflict management; Drivers and processes of change. Colombo, Sri Lanka: CGIAR Challenge Program on Water and Food. pp.69-74.
Erosion control ; Soil conservation ; Catchment areas ; Watershed management ; Environmental management ; Environmental protection ; User charges ; Farmers ; Stakeholders ; Sloping land ; Crop production ; Case studies / South East Asia / Vietnam / Thailand / Laos / Mekong Region
(Location: IWMI HQ Call no: IWMI 333.91 G000 HUM Record No: H041852)
http://cgspace.cgiar.org/bitstream/handle/10568/3708/IFWF2_proceedings_Volume%20III.pdf?sequence=1
https://vlibrary.iwmi.org/pdf/H041852.pdf
https://vlibrary.iwmi.org/pdf/H041852.pdf
(0.15 MB)
5 Bourdon, Emmanuel; Blavet, D.; Luankongkam, O.; Soulileuth, B.; Chanhphengxay, A.; Pierret, Alain; Ribolzi, Olivier. 2008. Semi-quantitative evaluation of waterlogging duration using two models based on soil colour in a representative upland catchment of northern Lao PDR. Lao Journal of Agriculture and Forestry, Special issue no.17:150-165.
Groundwater ; Waterlogging ; Soil properties ; Water table ; Catchment areas ; Models / Laos / Houay Pano catchment
(Location: IWMI HQ Call no: e-copy only Record No: H041771)
(0.57 MB)
Groundwater is a vital resource for rural populations in tropical areas who depend on seasonal rainfall. Groundwater is often the only source of water feeding streams, allowing them to flow throughout the dry season. The aim of this study was to evaluate two models for estimating the average duration that soil is waterlogged by shallow groundwater table. These models, based on variations in soil colour, were developed by Blavet et al (2000) from observations and measurements made in a semi-arid environment in West Africa. Therefore there is a need to evaluate whether these models are also pertinent in a mountainous context of northern Laos. Our approach consisted in comparing data obtained from field measurements (water table level, morpho-pedological features including soil colour) with predictions made by the models. This study was carried out along two transects with contrasting characteristics in terms of the landscape morphology as well as the soil hydrodynamic: the first was in an open swampy valley with convex hillslopes, the second was in a steep-banked and narrow valley with convexo-concave hillslopes. Preliminary results from our study identified relationships between soil colour and the mean rate of soil waterlogging and are a first step for developing an inexpensive and simple method to predict soil saturation in this environment.
6 Vigiak, Olga; Ribolzi, Olivier; Pierret, Alain; Sengtaheuanghoung, O.; Chaplot, Vincent; Valentin, Christian. 2008. Estimation of runoff curve number (CN) of some Laotian land use types. Lao Journal of Agriculture and Forestry, 16:49-60.
(Location: IWMI HQ Call no: e-copy only Record No: H041781)
(0.34 MB)
7 Mousques, C.; George, A.; Sengsoulichanh, P.; Latchackack, K.; Sengtaheuanghoung, O.; Ribolzi, Olivier; Pierret, Alain. 2008. Relevance of Payments for Environmental Services (PES) for watershed management in northern Lao PDR. Lao Journal of Agriculture and Forestry, Special issue no. 17:129-148.
(Location: IWMI HQ Call no: e-copy only Record No: H041947)
http://www.nafri.org.la/documents/newsletter/Journal/journal_17/section7.pdf
https://vlibrary.iwmi.org/pdf/H041947.pdf
https://vlibrary.iwmi.org/pdf/H041947.pdf
(0.72 MB)
8 Valentin, Christian; Lestrelin, Guillaume; Chanthavongsa, A.; Phachomphon, K.; de Rouw, Anneke; Chanhphengxay, A.; Chaplot, V.; Bourdon, Emmanuel; Briquet, J. P.; Marchand, P.; Pierret, Alain; Ribolzi, Olivier; Thiebaux, Jean-Pierre. 2008. The MSEC project in the Lao PDR at a glance: biophysical and socio-economic background and project experimental set up. Lao Journal of Agriculture and Forestry, Special issue no.17:32-50.
Erosion ; Runoff ; Land use ; Policy ; Crop production ; Catchment areas ; Rice ; Shifting cultivation ; Social aspects / Laos
(Location: IWMI HQ Call no: e-copy only Record No: H041777)
http://www.nafri.org.la/documents/newsletter/Journal/journal_17/section2.pdf
https://vlibrary.iwmi.org/pdf/H041777.pdf
https://vlibrary.iwmi.org/pdf/H041777.pdf
(0.83 MB)
9 Ribolzi, Olivier; Thiebaux, Jean-Pierre; Bourdon, Emmanuel; Briquet, J. P.; Chaplot, V.; Huon, S.; Marchand, P.; Mouche, E.; Pierret, Alain; Robain, H.; de Rouw, Anneke; Sengtahevanghoung, O.; Soulileuth, B.; Valentin, Christian. 2008. Effect of fallow regrowth on stream water yield in a headwater catchment under shifting cultivation in northern Lao PDR. Lao Journal of Agriculture and Forestry, Special issue no.17:52-71.
Water yield ; Runoff ; Water balance ; Shifting cultivation ; Stream flow ; Water uptake ; Groundwater depletion ; Land use ; Water table / Laos
(Location: IWMI HQ Call no: e-copy only Record No: H041774)
http://www.nafri.org.la/documents/newsletter/Journal/journal_17/section3.pdf
https://vlibrary.iwmi.org/pdf/H041774.pdf
https://vlibrary.iwmi.org/pdf/H041774.pdf
(0.53 MB)
10 Valentin, Christian; Sengtahevanghoung, O.; Ribolzi, Olivier; Pierret, Alain; Vigiak, Olga. 2008. The MSEC project in the Lao PDR: achievements, ongoing activities and perspectives on sustainable alternative farming practices for the uplands. Lao Journal of Agriculture and Forestry, Special issue no.17:2-30.
Land use ; Soil conservation ; Sloping land ; Erosion ; Shifting cultivation ; Farming systems / Laos / Houay Pano catchment
(Location: IWMI HQ Call no: e-copy only Record No: H041776)
http://www.nafri.org.la/documents/newsletter/Journal/journal_17/section1.pdf
https://vlibrary.iwmi.org/pdf/H041776.pdf
https://vlibrary.iwmi.org/pdf/H041776.pdf
(0.98 MB)
11 George, A.; Pierret, Alain; Boonsaner, A.; Valentin, Christian; Orange, Didier; Planchon, O. 2009. Potential and limitations of Payments for Environmental Services (PES) as a means to manage watershed services in mainland Southeast Asia. International Journal of the Commons, 3(1):16-40.
Watershed management ; Reservoirs ; Water quality ; Erosion ; Environmental management ; User charges ; Farmers ; Poverty ; Social aspects ; Economic aspects ; Highlands ; Water users ; Surveys ; Case studies ; Institutions / South East Asia / Laos / Thailand / Mae Thang Watershed / Houay Xon Watershed / Luang Prabang
(Location: IWMI HQ Call no: e-copy only Record No: H042327)
http://www.thecommonsjournal.org/index.php/ijc/article/viewPDFInterstitial/131/84
https://vlibrary.iwmi.org/pdf/H042327.pdf
https://vlibrary.iwmi.org/pdf/H042327.pdf
(0.38 MB)
Based on two case studies conducted at local sites in Northern Thailand and Lao PDR, the objectives of this paper are (i) to assess whether conditions for the establishment of PES at the watershed level exist in the uplands of mainland SE Asia and (ii) to examine and discuss limitations that are likely to impinge on direct transfer of the PES concept as well as the institutional adaptations and support that are required for the successful implementation of PES markets in this regional context. The study’s main findings are that: (i) acceptance of PES principles and constraints are directly related to stakeholders’ perception of their land rights irrespective of their actual rights; (ii) willingness to pay (WTP) is very low among local stakeholders, making any PES market unlikely to emerge without external support; (iii) the classical scheme for watershed services hardly applies in its original form because environmental service (ES) providers and buyers are generally the same people; (iv) where potential ES buyers feel that ES providers are better-off or wealthier than them, they do not have any WTP for ES; (v) good governance, including a strong liaising at various levels between people and the authorities is a strong prerequisite for the successful establishment of PES markets, even without direct government funding.
12 Pages, L.; Serra, V.; Draye, X.; Doussan, C.; Pierret, Alain. 2009. Estimating root elongation rates from morphological measurements of the root tip. Plant and Soil, 328(1-2):35-44. [doi: https://doi.org/10.1007/s11104-009-0079-x]
(Location: IWMI HQ Call no: e-copy only Record No: H042680)
(0.19 MB)
To measure the elongation rate of individual roots in soil remains a challenge. A novel method for estimating elongation rates of excavated roots is presented. Morphological markers are identified along the tip of excavated roots, and their distance relative to the apex is measured. These markers correspond to developmental stages which follow known temporal patterns. Hence, their distance relative to the apex reflects root elongation during the period corresponding to their development. The method was tested on maize roots grown in a range of conditions and substrates. It was found that distances from markers to apices were proportional, with some variability, to elongation rates. Remarkably, the linear relationships between these distances were neither affected by substrate, nor by growing conditions. Using several markers allows covering time periods ranging from 0.3 day to 3 days as well as cross validation of estimates. Provided further testing, under a wider range of environmental conditions, is conducted, the concepts presented in this paper may serve to define a new measurement technique.
13 Pierret, Alain; Doussan, C.; Capowiez, Y.; Bastardie, F.; Pages, L. 2007. Root functional architecture: a framework for modeling the interplay between roots and soil. Vadose Zone Journal, 6(2):269-281. [doi: https://doi.org/10.2136/vzj2006.0067]
(Location: IWMI HQ Call no: e-copy only Record No: H033450)
(0.43 MB)
Soil ecosystems support a plethora of intertwined biophysical and biochemical processes. Soil structure plays a central role in the formation and maintenance of soil biological activity by providing a diversified habitat for soil organisms and determining the movement and transport of the resources on which they rely. At the same time, the formation and preservation of soil structure and fertility is also strongly linked to soil biological activity through feedback loops. In most soil ecosystems, soil biological activity and associated processes are concentrated in the soil located around living plant roots and influenced by root activity, an environment known as the rhizosphere. Consequently, among the wide array of soil life forms, plants play a dominant role in the regulation of many soil processes. In this paper, we illustrate the functional complexity of soil ecosystems using specific examples of root–soil interactions and associated processes. Through examples taken from the literature, we examine the origins and variations in soil physical, chemical, and biological properties and their impact on root growth. Next, we consider how the response of root systems to their environment affects resource acquisition by plants. Finally, we describe how the concept of root functional architecture can improve the integration of research advances from fields operating as independent disciplines and improve our understanding of soil ecosystems.
14 Planchon, O.; Pierret, Alain; Orange, Didier. 2009. Relevance and feasibility of PES to combat soil erosion and solve catchment management issues: three case studies in Southeast Asia. Project completion report of the Payment for Environmental Services initiative of Theme 2 of the CGIAR Challenge Program on Water and Food (CPWF), 2007-2008. 146p.
Environmental protection ; User charges ; Water pollution ; Erosion ; Land use ; Water quality ; Watersheds ; Waste management ; Biofuels ; Biogas ; Case studies / South East Asia / Laos / Thailand / Vietnam / Houay Xon / Ban Lak Sip / Ban Donkang / Phrae Province / Mae Thang Watershed / Ban Pong / Tien Xuan Commune / Dong Xuan Commune / Cua Khau Dam
(Location: IWMI HQ Call no: e-copy only Record No: H043015)
(3.66 MB)
15 Lacombe, Guillaume; Pierret, Alain; Hoanh, Chu Thai; Sengtaheuanghoung, O.; Noble, Andrew. 2010. Conflict, migration and land-cover changes in Indochina: a hydrological assessment. Ecohydrology, 3(4):382–391.
Hydrology ; River basins ; Land cover ; Forests ; Evapotranspiration ; Rainfall-runoff relationships ; Time series analysis ; Models / Southeast Asia / Laos / Myanmar / Thailand / Vietnam / Mekong River Basin / Indochina
(Location: IWMI HQ Call no: e-copy only Record No: H043213)
(0.35 MB)
The Indochinese section of the Mekong Basin has been subjected to major environmental disturbances over the last half century. The Vietnam War is invoked as a central explanation for the extensive deforestation in specific areas while conflictinduced exoduses caused the abandonment of cultivated lands, followed by forest regeneration. Although the socio-economical consequences of these episodes have been analysed, their hydrological impacts remain unknown. This paper investigates hydrological changes in two catchments of the lower Mekong Basin that were either heavily bombed (in southern Laos) or depopulated (in northern Laos). This analysis is based on the widely and independently recognized fact that vegetation, via evapotranspiration, is a central driver of basin water yield. The analysis of the most complete Vietnam War air mission database and of available hydro-meteorological data over the period 1960–2004 reveals a sharp runoff increase in the southern catchment when bombing climaxed in the early 1970s while no hydrological change is observed in the northern catchment over the same period. From 1995 onwards, the northern and southern catchment’s runoff productions are significantly lower and higher than in the pre-war conditions, respectively. Although causalities could not be ascertained because of data limitations, these short- and long-term hydrological shifts were found to be consistent, in terms of occurrence, spatial distribution and magnitude, with the expected changes in the vegetation cover, either denser in the north (in response to abandonment of cultivated lands) or sparser in the south (as a result of bomb-induced deforestation and soil degradations).
16 Lacombe, Guillaume; Hoanh, Chu Thai; Pierret, Alain; Sengtaheuanghoung, O.; Smakhtin, Vladimir; Noble, Andrew. 2010. Climate change versus land-cover change: a comparative analysis in the Mekong Basin. In Herath, S.; Wang, Y.; Liang, L. (Eds.). Meeting climate change challenges in transboundary basins: role of sciences. Tokyo, Japan: United Nations University (UNU). Institute for Sustainability and Peace (ISP). pp.29-31. (Climate and Ecosystems Change Adaptation Research (CECAR) 4)
Climate change ; Land cover ; Analysis ; River basins ; Catchment areas ; Rainfall-runoff relationships / South East Asia / Mekong River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H043309)
(4.77 MB)
17 Lacombe, Guillaume; Pierret, Alain; Hoanh, Chu Thai; Sengtaheuanghoung, O. 2010. Hydrological consequences of armed conflicts and massive migrations in the Lower Mekong Basin over the second half of the 20th Century. [Abstract only]. Paper presented at the Hydrology Conference 2010, San Diego, California, USA, 11-13 October 2010. 2p.
(Location: IWMI HQ Call no: e-copy only Record No: H043383)
(0.17 MB)
We investigated whether the Vietnam War bombing and conflict-induced exodus could have altered the hydrological behaviour of the Mekong Basin. The rainfall-runoff relationship was analysed in 2 catchments over period 1960-2004 (figure 1). In each catchment, rainfall and runoff time series together with potential evapotranspiration were used as input to run GR2M monthly water balance model whose robustness is adapted to data-scarce conditions. The space-time distribution of densities of bombs dropped during the war was derived from UXO-NRA database which records the amount and type of ordnances and the aircraft types and numbers per US Air Force sorties from 1965 to 1973. Bomb-induce damages inflicted on vegetation was estimated using the Bomb Damage Assessment Report. We found that the delivery of about 1.5 million tons of high-explosive ordnances likely caused profound damage to one third of the southern catchment whose runoff increased by >365 mm/year during at least 4 years after bombing climaxed in 1972. The magnitude of this increase was found to be consistent with usual tropical forest transpiration rates over the bomb-cleared surface area. No hydrological change was observed during this period in the 30-fold-less bombed catchment located in the North. From 1995 onward, southern and northern catchments’ runoff productions are significantly higher and lower than in pre-war conditions, respectively. These hydrological shifts are most likely attributed to permanent changes in the vegetation cover, either denser in the northern sub-catchment (in response to the extensive abandonment of cultivated lands) or sparser in the southern catchment (as a result of bomb-degraded soil conditions). These results illustrate the high responsiveness of flow regime to forest cover changes in tropical areas where deforestation is expected to perpetuate at a high rate over the coming decades.
18 Ribolzi, O.; Cuny, Juliette; Sengsoulichanh, Phonexay; Mousques, Claire; Soulileuth, Bounsamai; Pierret, Alain; Huon, S.; Sengtaheuanghoung, O. 2010. Land use and water quality along a Mekong tributary in northern Lao P.D.R. Environmental Management, 47(2):291-302. [doi: https://doi.org/10.1007/s00267-010-9593-0]
Land use ; Water quality ; Measurement ; Water pollution ; Rivers ; Highlands ; Wastewater ; Surveys / Laos / Mekong Basin tributary / Houay Xon Stream / Luang Prabang Province
(Location: IWMI HQ Call no: e-copy only Record No: H043454)
(0.65 MB)
Improving access to clean water has the potential to make a major contribution toward poverty reduction in rural communities of Lao P.D.R. This study focuses on stream water quality along a Mekong basin tributary, the Houay Xon that flows within a mountainous, mosaic land-use catchment of northern Lao P.D.R. To compare direct water quality measurements to the perception of water quality within the riparian population, our survey included interviews of villagers. Water quality was found to vary greatly depending on the location along the stream. Overall, it reflected the balance between the stream self-cleaning potential and human pressure on the riparian zone: (i) high bacteria and suspended load levels occurred where livestock are left to free-range within the riparian zone; (ii) very low oxygen content and high bacteriological contamination prevailed downstream from villages; (iii) high concentrations of bacteria were consistently observed along urbanized banks; (iv) low oxygen content were associated with the discharge of organic-rich wastewater from a small industrial plant; (v) very high suspended load and bacteria levels occurred during flood events due to soil erosion from steep cultivated hill slopes. Besides these human induced pollutions we also noted spontaneous enrichments in metals in wetland areas fed by dysoxic groundwater. These biophysical measurements were in agreement with the opinions expressed by the majority of the interviewees who reported poor and decreasing water quality in the Houay Xon catchment. Based on our survey, we propose recommendations to improve or maintain stream water quality in the uplands of northern Lao P.D.R.
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