The Case Study on Structure of Large?sized Paddy Fields

In the cases of KAKURAI and USUI project area in Sakura City, Chiba Prefecture

Abstract

Trying for efficient agricultural management and improvement in crop intensity, large-sized paddy field is required in flat land. This paper focused on the characteristics of paddy field structures of the Kakurai area and Usui area in Chiba Prefecture, where they have been consolidated into large-sized paddy fields with various improvements based on present standard lot structure. Specifically, we estimated the functions and effects of paddy field structures from the viewpoints of irrigation and drainage, efficiency of agriculture operation, water management and so on.
Through the research, the authors found the following results:
1) In these areas, the plots have being expanded by farm block leveling through soil dressing, adjustment of the contours through land grading and took off levees during and after the farm land consolidation projects, and large-sized plots were found as large as 6.8ha, 2.5ha in 1992. Also, there is few problem even in leveling 6.8 ha plot using a laser guided bulldozer, but there is also an example that 5.2 ha plot is divided into 3 plots with insufficiency of land leveling in the irregular sized and land subsided farm block.
2) There are no problems as regarding irrigation and drainage in the large-sized paddy fields of 6.8ha, 2.1 ha and so on. This is obtained by buried irrigation and drainage canal, dual-purpose underdrainage system, as well as automatic watering.
3) Efficient agriculture management has become true in the large-sized paddy fields due to efficient farm machine operation, labor-saving of water management operation and adding effect of direct seeding culture of paddy rice on well-drained paddy field and so on.