Technologies are described for devices and methods to irrigate a crop. The systems may comprise an irrigation processor configured to be in communication with, a memory, a soil moisture tension sensor, an infrared camera, and a valve. The irrigation processor may receive an input, soil moisture tension data, infrared data, ambient temperature data, humidity data, and weather data, and store each in the memory. The input may include a crop, an area planted, and a location. The irrigation processor may generate an output of a crop water stress index. The irrigation processor may generate a water requirement. The irrigation processor may determine an irrigation requirement. The irrigation processor may generate a determination to irrigate based on the soil moisture tension data, the output of the crop water stress index, and the irrigation requirement. The irrigation processor may operate the valve to irrigate based on the determination to irrigate.