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Cluster Analysis of Spatiotemporal Corn Yield Patterns in an Iowa Field

USDA-ARS, National Soil Tilth Lab., 2150 Pammel Dr., Ames, IA 50011

View larger version (74K): [in a new window]   Fig. 1. Distribution of (a) 224 yield plots, (b) elevation, (c) 0 to 255 gray-scale soil color, and (d) apparent electrical conductivity within a 32-ha field.

View larger version (53K): [in a new window]   Fig. 2. Elevation and spatial distribution of the 224 yield plots in the southern half of the 32-ha field assigned to the five yield clusters.

View larger version (18K): [in a new window]   Fig. 3. Average corn yield by year for each cluster. Years when growing season precipitation was less than the 40-yr average are identified as dry and those greater than the 40-yr average as wet.

View larger version (22K): [in a new window]   Fig. 4. Cluster assignment of the 224 yield plots plotted against the first two canonical composites determined for the field attributes.

View larger version (9K): [in a new window]   Fig. 5. Stretched loading vectors for soil electrical conductivity (EC), soil color (SC), elevation (EL), plan curvature (PL) profile curvature (PR), and slope (SL), and cluster means plotted on the first two rotated canonical composites. The PR vector is obscured by other vectors.

View larger version (77K): [in a new window]   Fig. 6. Spatial distribution of the four yield clusters (Cluster 1&2, toeslope; Cluster 3, footslope; Cluster 4, shoulder; Cluster 5, backslope) across the 32-ha field as predicted from the multiple discriminant analysis and significant field attributes.