A disc harrow implement has gang assemblies each having aligned disc gangs carried by a support bar. Each disc gang has disc blades spaced along an axis of the disc gang. The disc gangs of each gang assembly are coaxially aligned to create a line of substantially equally spaced disc blades. A plugging detection system alerts an operator if one or more of the disc gangs are rotating at a rotational speed that is slower than rotational speeds of the remaining disc gangs. The plugging detection system includes a gang rotation sensor for each of disc gangs. Each gang rotation sensor is configured to measure the rotational speed of the connected disc gang. A control module compares the rotational speed of each disc gang to the rotational speed of the disc gangs and generates an output that indicates when a disc gang is rotating more slowly that the other disc gangs.