Real-time system for determining corn plant population in-situ at harvest time

Producers and seed companies have recently expressed interest in documenting spatial variation in com plant population. In order to measure plant population at harvest-time, the number of com stalks feeding into the harvester must be known. A system has been developed to measure plant population on a combine com header. It uses a non-intrusive capacitive technique to sense com stalks as they enter the header. Stalks pass the sensor face, and an increase in voltage is produced due to a change in sensor capacitance. This voltage increase is recorded as one com stalk. The system was prototyped and tested in both laboratory and field environments. Test results show that the system is capable of measuring plant population to some degree of accuracy. Accuracy measurements were based on manual stalk counts performed before harvesting. Field tests were inconclusive due to insect damage coupled with late season harvest resulted in a severally lodge crop. Accuracy was moderately correlated with speed (r = 0.43: α=0.05). Refinements in sensor head design and measurement circuitry are needed to improve measurement accuracy. Future tests should include com stalks of various moisture contents to determine if moisture related problems exist.