Land use change and soil and water processes in tropical mountain environments

LAND USE CHANGE AND SOIL AND WATER PROCESSES IN TROPICAL MOUNTAIN ENVIRONMENTS

This symposium follows the symposium held in Quito, Equator, December 2002 ‘Land use change and geomorphic, soil and water processes in tropical mountain environments’. It aims at bringing together scientists from various disciplines dealing with land use and soil and water management in tropical mountain areas. The main objectives of the symposium are:

· To exchange information and scientific findings on the effects of land use change on soil and water processes in tropical mountain areas in a broad sense.

· To identify the gaps in our knowledge and understanding of the response of soil and water dynamics in tropical ecosystems to land use change.

· To formulate research strategies and guidelines that will allow advancing our understanding of the response of soil and water processes to land use change in tropical mountain areas.

· To reflect on suitable strategies for the sustainable development of tropical mountain areas.

Key topics

· Impact of land use/-cover change on soil erosion processes, such as tillage erosion, water erosion and mass movements

· Assessment of the proportion of anthropogenic and natural degradation in mountain areas

· Development of suitable strategies for sustainable land and water management.

Symposium organizing and scientific committee

·         Dr. Bounthong Bouahom, fodder scientist
Director General,
National Agriculture and Forestry Research Institute
Vientiane, Lao PDR

·         Mr Anolath Chanthavongsa, soil scientist
Director,
Soil Survey and Land Classification Center
Vientiane, Lao PDR

· Dr Fahmuddin Agus, soil scientist
Director
Soil Research Institute (SRI),
Bogor, Indonesia

· Dr Tran Duc Toan, soil scientist
Deputy Director,
National Institute for Soils and Fertilizers
Hanoi, Vietnam

· Mr Ian Makin, hydrologist
Regional Director,
International Water Management Institute (IWMI),
Bangkok, Thailand

· Dr. Christian Valentin, soil scientist
Institut de Recherche pour le Développement - International Water Management Institute,
Vientiane, Lao PDR

· Dr Bruce Linquist, crop scientist
International Rice Research Institute (IRRI),
Luang Phrabang, Lao PDR

· Dr Rod Lefroy, soil scientist
Regional Director,
Centro Internacional de Agricultura Tropical (CIAT)
Vientiane, Lao PDR

· Prof. Dr. G. Govers, geomorphologist
Laboratory for Experimental Geomorphology, Department Geography – Geology
Katholieke Universiteit Leuven, Belgium

· Prof. Dr. J. Poesen, geomorphologist
Laboratory for Experimental Geomorphology, Department Geography – Geology
Katholieke Universiteit Leuven, Belgium

· Mr Pouthone Sopathirath, fodder scientist
Integrated Upland Research Programme Leader
National Agriculture and Forestry Research Institute
Vientiane, Lao PDR

· Mr Oloth Sengthahuanghung, soil scientist
Asialand/Sloping Land Project coordinator in Lao PDR
National Agriculture and Forestry Research Institute
Vientiane, Lao PDR

· Dr. Anneke de Rouw, crop and weeds scientist
Institut de Recherche pour le Développement - International Water Management Institute,
Vientiane, Lao PDR

· Dr. Vincent Chaplot, soil scientist
Institut de Recherche pour le Développement - International Water Management Institute,
Vientiane, Lao PDR

· Dr. Bernard Moizo, anthropologist
Institut de Recherche pour le Développement,
Vientiane, Lao PDR

· Dr Arthorn Boosonner, hydrologist
National Park, Wildlife and Plant Conservation Department (NPWPCD)
Phrae, Thailand

· Dr. Pascal Podwojewski, soil scientist
Institut de Recherche pour le Développement - International Water Management Institute,
Hanoi, Vientiane

· Dr. Didier Orange, hydrologist
Institut de Recherche pour le Développement - International Water Management Institute,
Hanoi, Vientiane

· Dr. Sylvain Huon, isotopic biogeochemist,
Université Pierre et Marie Curie
Paris, France

Provisional programme

The meeting will be organised in Luang Phrabang, the capital of a mountainous province in Lao PDR.

Monday	13/12	18.00 – 19.00	Arrival of participants Registration
Tuesday	14/12	8.00-9.00 9.00 – 9.30 10.00-12.00 13.00-17.00 19.00	Registration Opening ceremony Presentation of papers/posters Presentation of papers/posters Symposium dinner
Wednesday	15/12	8.00 – 12.00 14.00-18.00	Presentation of papers/posters Field visit of the Houay Pano catchment located at 10 km from Luang Phrabang" including the experiments of the Managing Soil Erosion Consortium.
Thursday	16/12	8.00 – 12.00 13.00-15.00 15.30-17.00	Presentation of papers/posters Presentation of papers/posters General discussion – Recommendations
Friday	17/12		Departure of participants for Vientiane or Bangkok

Registration fee

The symposium registration fee will be of the order of 150 USD for non-Lao participants. This registration fee will cover all symposium materials, a book of abstracts, the symposium field guide, and the symposium dinner.

The transfer Vientiane-Luang Phrabang or Bangkok-Luang Phrabang are not included in this fee.

If necessary, the organizing committee will assist the participants for air booking and guest house reservation in Luang Phrabang.

Travel assistance

Participants are encouraged to seek travel support from their own government agencies or program sponsors. The symposium organising committee will be pleased to write pro forma letters of invitation to the symposium, in order to support qualified symposium participants in applying for financial assistance for travel and accommodations. These pro forma letters of invitation do not include any financial commitment of the organising committee. In general, no travel assistance will be available through the Symposium organising committee. However, sources of funds to provide travel assistance to a limited number of participants are currently being investigated. Participants needing travel support from the organising committee are asked to contact the committee as soon as possible.

Participants are urged to make airline reservations well in advance because the demand for airline tickets to Thailand and Lao PDR is very high in December. Luang Phrabang can be reached from Vientiane, Lao PDR, Bangkok and Chiang Mai, Thailand.

Call for abstracts

Abstracts for poster and/or oral presentations should be submitted in a soft copy as Microsoft Word or ASCII text. Abstracts should not exceed 400 words in length and the format should be as the attached example. All abstracts must include the author's name and affiliation, as well as the mailing address, telephone and fax number and an e-mail address of the corresponding author. Abstracts should be sent by e-mail to valentinird@laopdr.com.

The deadline for submission of all abstracts is September 15, 2004. Individuals who submit abstracts will be informed about the acceptance of their abstracts for an oral or a poster presentation by October 1, 2002.

All abstracts accepted for presentation during the symposium "Land use change and geomorphic, soil and water processes in tropical mountain environments" will be published in a book of abstracts that will be made available to all participants at the onset of the symposium.

Publication of papers

Selected papers could be published as regular articles after normal peer review procedures in four proposed international scientific journals: Agriculture, Ecosystems and Environment; Catena, Geomorphology; Journal of Hydrology.

Housing accommodation

Symposium participants are requested to book themselves a guest house room for December 19-22, in Luang Phrabang. A short list of guesthouses with their email address with fares ranging from USD 25 to 100 per night will be circulated. Participants will be urged to make reservations for their accommodation and flights very early because December is the peak season in Luang Phrabang.

Timetable and Deadlines

Dynamic modelling for gully initiation and development under climate and land-use changes in northern Laos

Chaplot V. ¹, Giboire G.², Marchand P.³ Valentin C.¹

¹Institut de Recherche pour le Développement (IRD)/International Water Management Institute (IWMI)/National Agricultural and Forestry Research Institute (NAFRI), BP 06, Vientiane, Lao PDR.

2 Faculté des Sciences Agronomiques, Université Catholique de Louvain, Croix du Sud 2, boite 2, B-1348 Louvain la Neuve, Belgique.

3 Institut de Recherche pour le Développement (IRD), BP 5045, 34032 Montpellier cedex, France

Erosion due to gullies has become a broad challenge for food supply, food security, human health and natural ecosystems. This issue is even more crucial in areas were rapid changes in land use and climate patterns may dramatically affect soil erosion. Gullies form when a hydraulic threshold for incision into a resistant soil surface is exceeded. Our main objective was to investigate to what extent one could use direct flow velocity estimations from GIS-based models for predicting gully initiation and development in agricultural landscapes. Secondly this study aimed at estimating the effect of land use and climate change on erosion by gullying.

The study was conducted in a 0.62 km² watershed of Laos (Southeast Asia) representative of the slash and burn systems under sloping land, without inputs but submitted to a reduction of the fallow period. During the 2001 rainy season, gully features were surveyed throughout the watershed after each rainfall event. Flow velocity was estimated using a surface water routing developed at Utrecht University. It uses as input data a DEM with a 10-m mesh was constructed by spline interpolation from field spot heights using theodolite, a soil and land use map. Input infiltration characteristics have been obtained from rainfall simulation. This model was run for each rainfall event responsible for gully features evolution. Scenarios of global change include: (i) an annual crop proportion of 65% and 100%; (ii) the generalisation of soil-conservation practices; (iii) an increase and a decrease by 20% of rainfall amount and maximum intensity. Throughout 2001 only two rainfall events, among the 150 registered events with a total amount higher than 2 mm, produced new rills. 14 gullies were formed with an erosion rate of 3.5 T/ha. Using modelling, a velocity threshold of 0.062 m.s^-1 over a 10-m width cell was estimated for gully initiation. Using a validation event, this threshold was useful for the prediction of gully length, with a prediction error of total gully length lower than 15%.

Increasing annual crop from 10 to 100% increased gully length by 600%. Climate change had less impact on gully formation. Finally, this approach that provides dynamic data for the prediction of erosion by gullying under global changes is discussed.

Keywords: gully, flow velocity, dynamic modelling, global change, Asia

Corresponding author: Vincent Chaplot, IRD, BP 06, Vientiane, Lao PDR, chaplotird@laopdr.com