Design and evaluation of a yield monitoring system for combinable crops
Keywords:wheat, spatial variability, yield map, mass flow sensor, precision farming
The existence of spatial variability within fields can be beneficial if inputs for arable crop are given to the field according to locally determined requirements. While yield mapping has become an important part of precision farming strategies, the goal of this paper is to plot a yield map by the application of yield monitoring components. A yield monitoring system capable of providing sufficient reliable data to plot a yield map for small grain fields in central regions of Iran was developed. The system consisted of an impact flow sensor determining the mass flow of grain, the GPS receiver determining geographical position of the machine, two shaft encoders measuring the speed of the combine, an ultrasonic sensor measuring the actual cutting width, and a data logger. The mass flow sensor consisted of a load cell and an impact plate which was exposed to the predominant grain flow from the clean grain elevator. This sensor was positioned in the transition housing between the elevator and the loading auger of the clean grain tank. The calibration of the sensor related the force on the sensor to the mass flow rate of grain. The yield data were used with information generated by the GPS receiver and a yield map was created. At last, the correlation between the maps and the data collected using traditional method was found which supports the reliability of the monitoring system.