FIRST, WHAT IS YIELD DATA?
Yield monitoring equipment was introduced in the early 1990s and is increasingly considered a conventional practice in modern agriculture. The pioneers of precision agriculture already have several years of yield history and have examined different ways of interpreting and processing these data.
Yield mapping refers to the process of collecting georeferenced data on crop yield and characteristics, such as moisture content, while the crop is being harvested with an onboard yield monitor. Various methods, using a range of sensors, have been developed for mapping crop yields.
The basic components of a grain yield monitor system, according to the Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln, include:
• Grain flow sensor – determines grain volume harvested
• Grain moisture sensor – compensates for grain moisture variability
• Clean grain elevator speed sensor – used by some mapping systems to improve accuracy of grain flow measurements
• GPS antenna – receives satellite signal
• Yield monitor display with a GPS receiver – used to georeference and record data
• Header position sensor – distinguishes measurements logged during turns
• Travel speed sensor – determines the distance the combine travels during a certain logging interval
Each sensor should be properly calibrated according to the operator’s manual. Calibration converts the sensor’s signal to physical parameters. A file is created during harvest to record the output of all sensors, and this file can be converted to a text format or displayed as a map using the yield monitor software.