About KITAGAWA IWAO
About TSUNETA DAISUKE
About 北海道農業開発公社
About HARAGUCHI NOBURO
About WAKASUGI KOSUKE
About 農業農村工学会誌
About farm land consolidation
About productivity
About farm land
About cost
About improvement
About underdrain
About durability
About condition
About 高生産性
About 穿孔暗渠
About low cost
About 適用条件
About 土層改良
About 排水改良
About Agricultural engineering
About コスト縮減
About 圃場整備
About 農地
About 段階
About 整備
About 排水改良