PROBLEM TO BE SOLVED: To automatically and efficiently manage water supply and waste in a field according to the growth character of crops in consideration of important factors capable of affecting the growth of crops, and the like, in a field water management system.SOLUTION: The present invention provides a field water management system 1 comprising: a supply plug 2 to supply water to a field H from an irrigation canal UL； a waste plug 4 to waste water in the field H to a waste canal DL, a field water temperature detection part 6 to detect the water temperature of the field H, a field water level detection part 8 to detect the water level of the field H, a time detection part 10 to detect time, and a controller 20 to control the start and stop of water supply by the supply plug 2 and the start and stop of waste by the waste plug 4 based on the detected information at least at the time among the temperatures of the field H detected by the field water temperature detection part 6, the water levels of the field H detected by the field water level detection part 8 and the times detected by the time detection part 10.SELECTED DRAWING: Figure 1
