UNDERGROUND IRRIGATION SYSTEM

PROBLEM TO BE SOLVED: To provide an underground irrigation system that can be suitably used on a slope land since the amount of moisture in a plough layer can be kept as even as possible without needing equipment such as water-table management equipment.SOLUTION: The underground irrigation system 10 includes a sealing member 12 to be buried in the ground of a cropland 200 and supplies water from the underground to keep the amount of moisture in soil in a state appropriate for the growth of a plant. The sealing member is formed of a material having a sealing property in an elongated groove-like shape and is buried in the ground with its longitudinal direction being along the slope of the cropland 200. A water-holding member 14 having a water-absorbing property and water-holding property is provided at the bottom of the inside of the sealing member 12, and a water supply member 16 is disposed through the water-holding member 14. In the underground irrigation system 10, water from a water supply source 30 is supplied to the water-holding member 14 by the water supply member 16 during the irrigation. The water absorbed and held by the water-holding member 14 is soaked up and supplied to the soil above by capillary action.