Spatial variability and temporal stability of corn (Zea maysL.) grain yields – relevance of grid size

Abstract

Corn yields are frequently heterogeneous across space and time. A 5-year field monitoring was conducted to determine spatial variability and temporal stability of corn grain yields within three farmer fields. The objectives of this study were to evaluate the spatial variability and temporal stability of yields. Therefore yield data was analysed at the field scale and for three different grid sizes. Results indicated that the grid size required to capture the spatial variability and temporal stability of yield differed over the fields. In general, smaller grid sizes were able to describe yield variability more precisely, whereas larger grid sizes were able to more accurately describe yield stability. To develop units for site-specific management, grid size should be determined in consideration of temporal yield stability and in consideration of the underlying factor leading to spatial yield variability. If the underlying factor is highly variable within the field, smaller grid sizes are useful. If the underlying factor is less variable within the field larger grid sizes seem to be more suitable for site-specific management.