抄録
1. The effect of nutrients in irrigation water on soil fertility is exaggerated. The fertility of alluvial soils is sustained by renewal of soil material itself by big floods, recurring with a long time interval and often disastrous, and the reductive condition of soil under inundation, besides the nutrient supply by irrigation water.
2. Year-round inundation may suppress laterization, but it could hardly have any noticeable effect in the case of Angkor because laterization is a process of tens or hundreds of thousands of years, while the inundation by irrigation lasted only five hundred years.
3. Even if it was really the case that failure of the hydraulic system would have weakened the agricultural base, the weakened agriculture might have been through the failure of water supply itself rather than through deterioration of the soil.
4. The absence of a sluice gate in the baray is sufficiently clear evidence to refute the possibility of irrigation by baray, as Van Liere mentioned. The arguments that the embankment was destroyed and rebuild each time of irrigation, and that the seepage was used for irrigation are unlikely.
5. The baray is not dug down, but occupies the original ground surface and is surrounded by ca. ten-meter high embankment. Therefore, in the absence of evidence for the existence of a device for raising water into the baray, it is unlikely that a river or canal on the original ground fed the baray.
