Yield Mapping

Yield Mapping is the process of measuring and recording crop harvest quantities at fine spatial resolutionSpatial ResolutionSpatial resolution defines the size of the smallest feature or ground area that can be distinguished in a spatial dat... across agricultural fields using GPSGPSThe Global Positioning System (GPS) is a satellite-based navigation system operated by the U.S. Space Force that prov...-equipped combine harvesters and grain flow sensors. As the harvester moves through a field, sensors continuously measure grain flow rate and moisture content while GPS records the precise location, creating a dense dataset of georeferenced yield measurements. These data are interpolated into continuous yield maps that reveal the spatial patterns of productivity within and across fields. Technology and Data Processing for Yield MappingModern combine harvesters equipped with yield monitoring systems measure grain mass flow using impact plate or optical sensors, grain moisture using near-infrared sensors, and harvest width using header position sensors. GPS receivers record the location of each measurement at sub-second intervals. Raw yield data requires cleaning to remove artifacts including start-and-stop pass errors, narrow pass width anomalies, moisture calibration drift, and GPS position lag. Geostatistical interpolation methods like krigingKrigingKriging is an advanced geostatistical interpolation method that uses the spatial covariance structure of sample data ... transform the cleaned point measurements into continuous raster maps of yield variation. Multi-year yield map analysis reveals persistent productivity patterns that distinguish inherent soil and terrain effects from transient weather and management influences. Applications and ChallengesVariable-rate prescription development uses yield maps combined with soil data and elevation models to create customized input application plans that match seeding rates, fertilizer, and amendments to the productivity potential of each field zone. Drainage and soil improvement planning targets investment in the lowest-yielding areas where physical soil constraints limit production. Hybrid and variety evaluation compares crop performance across different field conditions using spatial yield data. Economic analysis calculates profitability by field zone rather than whole-field averages. Key challenges include the need for consistent calibration of yield sensors across different crop types and moisture conditions, the multiple-year data collection required to identify stable yield patterns, and the complexity of attributing yield variation to specific causal factors among the many interacting influences on crop production.