*4.1. Plant and Grain Nutrient Analyses*

Plant nutrient values for Ca, Mg, and protein were considerably higher for the US compared to ET (Table 2). Mean Ca was five to six times higher; mean Mg almost four times higher; and mean protein nearly 2.5 times higher in the US. Results were similar for grain nutrients (Table 2), with values in the US typically two to four times higher than ET. Additionally, the standard deviation and ranges for Ca and protein at both the plant and grain level were higher in the US, except for Mg, which showed similar standard deviation and ranges across both locations for plant and grain.


**Table 2.** Descriptive statistics for the calcium (Ca), magnesium (Mg), and protein measured for the plant and grain samples from each location.

#### *4.2. Model Performance*
