2006 Volume 103 Pages 13-22
The project areas to consolidate paddy fields have been shifting from flat to sloping terrain since around 1980. Studies from various aspects on shifting to sloping areas were carried out to solve the foreseeable problems about such consolidation of paddy fields. However, further technical problems occurred while implementing these projects. For example uneven rice growing areas appeared in the central areas of paddy lots after consolidation. Areas where rice was growing unevenly were becoming overlaid with piled surface soil during consolidation works. The survey revealed the lack of plowsole, and sedimentation of the original surface soil occurred in the same location where uneven rice was growing right after consolidation. The survey also revealed that the uneven rice fields remained after 15 years of consolidation, and that bearing capacity of foundation soil around the central part of a paddy lot was lower than the periphery. The consolidations have long-term effects on the conditions of soil and rice cultivation. Therefore, it is important to consolidate farmland foundations in order to make farmland adequate for rice production.
