An extensive field survey was conducted in the tropical peat swamp forest area in Narathiwat of the southern part of Thailand in August 1999. That field survey aimed at building an ecological environmental GIS database for monitoring carbon balance in the tropical peat swamp forest area. Then a peat depth survey was conducted to obtain a map of the distribution of peat depth in 1999, and the amount of peat in Bacho area was estimated. Next, a map of the distribution of vegetation there was essential to estimate the amount of biomass of vegetation above the ground.
Four vegetation types were classified by analyzing some of the satellite remote sensing images including optical remote sensing data and microwave remote sensing data. A vegetation map which has four vegetation categories was obtained.

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A study on “the Improvement Strategy of Hydro-Meteorological Network in the Lower Mekong River Basin” has been carried out as one of the components of the Hydrology Programme of the Mekong River Commission (MRC), which was based on a review of the network's historical development and present conditions. Reinforced with data/information collection, the strategic master scheme of improvement has been clarified.
The goal that was set is: “The network of hydro-meteorological stations shall provide timely, sufficient and reliable data and information to water management and water-related programmes and projects at both the regional and national levels.” To achieve this goal, four master scheme components are proposed, as follows:
(1) Proper network configuration: Hydrological network design is revised, and network improvement procedures are proposed by network classifications in each riparian country.
(2) Quality control of hydrological data: Quality control procedure is proposed focusing on the preparation of checklists for monitoring activities.
(3) Institutional strengthening: In parallel with efforts to solve the budgetary constraints, necessary practises are proposed to augment line agencies' presence.
(4) Capacity building: To build up the capacity of human resources in the line agencies, necessary actions to be taken by the MRCS are proposed.

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Mulching to reduce evaporation losses (EL) from small farms, which are the predominant agricultural production systems in the arid and semi-arid regions of Africa and Asia, is a common practice. To increase crop yield in these farms, irrigation seems to be a necessity. However, the water resources available for irrigation in arid and semi-arid environments are limited and saline (high electrical conductivity) or capable of inducing salinity through shallow groundwater table development. In this context, we reviewed the information available in the literature on mulching, evaporation, and salinity (MES) interrelation in order to assess the sustainability of the agricultural production systems in small farms using saline water for irrigation and mulches. It is surprising to find that information on MES interrelation is practically nonexistent even from drying column experiments. However, results from a 4-6-year in-situ vegetable-legume rotation study, where the legume was a cover crop, in California indicate that potential exists for salt accumulation in the rootingzone under saline drainage water irrigation. Without exception, almost all the reviewed studies show substantial reduction in EL under mulches. Three new issues, however, emerged from the review. First, though gravel mulching reduced EL, the savings could be counterbalanced by gravel-induced reduction in water vapor adsorption during the night. Second, the influence of gravel mulch on EL and rainfall infiltration was determined by gravel size. Third, the depth and rate of straw mulch incorporation had significant influence on EL. The review indicated the need for information on EL and water vapor adsorption under different mulches, mulch rates, mulch incorporation depth, and the MES interrelation under these different scenarios. In the absence of sufficient information in the above complex interrelation, it is suggested that for immediate need, surveys of saline water irrigated field histories be supplemented with drying column experiment results to seek answers about this complex interrelation.

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In devising an agricultural policy in Japan, the difficulty lies in that the policy must deal with the unpredictability of the food supply in the long-term perspective, while acting on the present structure of agricultural production which has been producing shortterm excesses. Considering the quite unfavorable conditions determining agricultural land resources in Japan (e.g., an absolute shortage of farmland resources that is aggravated because existing farms are frequently abandoned), it is necessary to separate the issue of agricultural land resource conservation from the issue of achieving the target of food selfsufficiency, and to take the necessary measures for agricultural land resource conservation immediately. The core of farmland policy lies in conservation of the agricultural land resources as such, and this issue is more serious than the issue of food self-sufficiency as related to the utilization of these land resources. This paper will propose extensive management as a means of conserving agricultural land resources and discuss basic concepts pertaining to this form of agricultural management.

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To develop numerical methods for one-dimensional open channel flows, we proposed a stable and high-resolved numerical method for discontinuous flow analysis, established a steady flow analysis method by the time marching method, and developed an efficient flow analysis method for large-scale channel networks.

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Soil erosion affects not only soil productivity of upland fields but also the water environment in streams further down the catchment. Severe eutrophication in reservoirs and canals is associated with nitrogen and phosphorus losses in surface runoff, and these have recently been the focus of intense research in Japan. This study dealt with eutrophic component losses in soil erosion processes and conservation strategy. It was reported that the loads of nitrogen and phosphorus losses increased with the amount of fertilizer applied in upland fields and with the percentage of upland fields in watersheds. Also, the outflow of nitrogen and phosphorus in bottom mud erosion, processes was investigated from the viewpoint of rheological properties. In addition, the structure of an underdrain pipe installed in a settling pond was discussed by evaluating the effect of a settling pond on soil and water conservation.
Thus this study, dealing with the transfer of soil particles and eutrophic components from sloping upland fields to drainage canals and conservation structures, offered knowledge and information for developing the technology of soil and water conservation in watershed management.
It was judged that this study merited the science encouragement award of JSIDRE.

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