Scale-Dependent Relationship between Wheat Yield and Topographic Indices
- Bing Cheng Si * and
- Richard E. Farrell
Topography can have a significant influence on crop yield, thus a better understanding of the effects of topographical parameters on crop yield is important—especially for site-specific soil management. The objective of this study was to determine whether topographical indices developed for hydrological studies could be used as indicators of crop yield using a wavelet approach. The effects of soil curvature, upslope length, and a wetness index on wheat grain yields in a hummocky terrain were investigated along a transect on a clay loam Black soil (Blaine Lake Association) in Saskatchewan, Canada. A wavelet approach was used to elucidate the processes underlying the relationships between crop yield and topographical parameters. Wheat grain yields had significant correlations with upslope length (R 2 = 0.60) and the wetness index (R 2 = 0.46), whereas soil surface curvature explained only 15% of the variations in grain yield. Wavelet analyses revealed that significant variations occurred at scales <160 m for wheat grain yield, 280 m for upslope lengths, and 110 m for the wetness index. The cross wavelet analysis indicated that significant covariance existed at scales <180 m between wheat grain yield and upslope lengths and at scales <140 m between wheat yield and the wetness index, at a 99% confidence level.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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