PROBLEM TO BE SOLVED: To provide a technique of being able to stably irrigate soil by utilizing a water pressure difference even if a rapid change of an external environment such as rapid rise of an outside air temperature, rapid vaporization of soil water, and rapid absorption of soil water by a plant at peak growth occurs.SOLUTION: In a method for irrigating soil, a water supply pipe is buried in soil, plural porous pipes being connected to in a conduit while disposed at proper positions of the conduit in the water supply pipe, fine pores being provided in a wall surface of the porous pipe, the fine pores being not provided in a wall surface of the conduit that is able to pass water both ends of the water supply pipe are connected to a water tank at positions lower than the porous pipe a water surface of the water tank is usually maintained at a level (horizontally) equal to or lower than the porous pipe the water supply pipe is saturated with water from the water tank water is intermittently supplied into the water tank and a position of the water surface in the water tank is set slightly higher than positions of the porous pipes buried in the soil, and a water partial pressure of the water tank is set to a slightly positive pressure.COPYRIGHT: (C)2011,JPO&INPIT【課題】 外気温度の急激な上昇による土壌水の急激な蒸発、生育最盛期にある植物による土壌水の急激な吸収などの外部環境に急激な変化が生じても、水圧差を利用した土壌への安定した潅水が継続的に可能な潅水技術を提供すること。【解決手段】 壁面に細孔が設けられていない通水可能な導管の適所に、壁面に細孔が設けられている多孔質管を、複数個配置して接続された送水管を土壌中に埋設され、この送水管の両端を多孔質管の位置よりも下方において貯水槽に接続し、通常は、貯水槽の水面は多孔質管と同位置(水平位置)ないし低位置に維持され、送水管を貯水槽からの水によって飽和させ土壌に潅水する方法において、間歇的に貯水槽内に水を供給し貯水槽内の水面の位置を土壌中に埋設した多孔質管の位置よりも若干高位置とし、貯水槽内の水分圧を微正圧にすることを特徴とする。【選択図】 図1
