Nonlinear Models for Analyzing NDVI-LAI Relationships in Multi-factor Soybean Experiments.

Nonlinear regression is more appropriate for many agronomic relationships.  One-factor experiments are relatively easy to fit non-linear equations.  However, many agronomic studies involve more that one factor, making the analysis more complicated.  A linear-plateau and their relatives anda variant of Mitscherlich's Yield Equation was used to analyze the relationship between soybean LAI and NDVI in a multi-factor treatment structure.  The experimental design was a randomized complete block with four replications and arranged in a split-plot arrangement.  NDVI was obtained from aerial images from three altitudes and three measurement dates.  Both non-linear models were suitable for the analysis of pooled data, but linear-slope models were the best fit of data when individual factors were extracted.