Abstract: A method of detecting the condition of a turf grass is described. According to one aspect of the invention, the method comprises steps of attaching an active sensor to a mower; traversing a section of turf grass; and processing the output of the sensor. A device for detecting the condition of turf grass is also disclosed. The device comprises an array of illuminating devices generating a pattern of illuminating light; a detecting device receiving a pattern of reflected light which is coincident with the pattern of illuminating light; a detecting device adapted to detect stray light from the array of illuminating devices; and a feedback loop controlling the array of illuminating devices. A system employing the device is also disclosed.

Abstract: A method and apparatus for the real time determination and application of optimum amounts of nitrogen fertilizer to corn and other arable crops such as cotton, sugar beats, wheat, etc. by the use of rapid, non-destructive sensors and various fertilizer application methods. In a first embodiment, optical reflectance measurements of the crop canopy and a reference strip at the fertilizer response plateau are taken by sensors carried by a center pivot irrigation system. A sensor controller receives, stores and analyzes the sensor data as well as position data received from a center pivot controller. The sensor controller then sends commands to the center pivot controller to order fertilizer application, as necessary, through the irrigation system. A second embodiment of the invention utilizes a tractor drawn fertilizer applicator with the sensors mounted on the application booms.