## 3 Results  
### Physiological, Biochemical, and Morphological Responses  
Figure 3 compares the sensitivity of seasonal canopy evapotranspiration (ET), leaf transpiration rate (\(\mathrm{T_{r}}\)), leaf photosynthetic CO\({}_{2}\) assimilation rate (A), and leaf stomatal conductance (\(\mathrm{g_{s}}\)) towards changing water availability based on the three water holding capacity (WHC) groups. Comparing among soil water status from 100% (wet/control) to 40%, (dry) soybean showed significant decreases in season average ET, \(\mathrm{T_{r}}\), A, and \(\mathrm{g_{s}}\) (\(p\)-value \(<\) 0.05). However, for maize the season average responses of leaf A, \(\mathrm{g_{s}}\), and \(\mathrm{T_{r}}\) were not sensitive to soil drought, while they were significantly higher for canopy ET from dry to wet soil water status. Maize A was significantly higher than in soybean plants for the same soil water stress, consistent with higher efficiency of C\({}_{4}\) metabolic path. \(\mathrm{T_{r}}\) and \(\mathrm{g_{s}}\) were also higher in maize than soybean, whereas maize ET at canopy level was significantly lower in each water group. Separating the influence of soil drought (WHC) and phenology (days of measurement, DoM) (Table 3), we saw significant differences for both treatments in soybean physiology (A, \(\mathrm{T_{r}}\), and \(\mathrm{g_{s}}\)) and biochemistry (chl) at the leaf level, but not for their interaction. Maize leaf parameters only showed a significant response to phenology, with similar variability (F-values) as in soybean parameters. At canopy level, ET of both crops were sensitive to soil drought and phenology (Table 3 and Figure 3), whereas \(\mathrm{h_{c}}\) only changed over time (Table 3 and Figure S1). In addition, phenology effects on canopy level parameters (ET and \(\mathrm{h_{c}}\)), were more than 150 times higher than replicates variability (F-values \(>\) 150) for maize, but not for soybean plants (Table 3). Interestingly, comparing wet and dry plants at each day of measurement, soybean and maize ET showed significant decrease since DoM 4. Besides that, soybean leaf chl significantly increased from very early in the growth cycle. However, other parameters such as A, T\({}_{\rm r}\), g\({}_{\rm s}\) or h\({}_{\rm c}\) were not sensitive in most of the dates (Figure S2). Physiological, biochemical, and morphological parameters (Figure S3) showed a normal distribution over time among WHC groups and replicates. A strong relation was observed between T\({}_{\rm r}\) and g\({}_{\rm s}\), showing \(p\)-value \(<\) 0.001 and coefficients of determination (R\({}^{2}\)) of 0.75 and 0.86 in soybean and maize, respectively. g\({}_{\rm s}\) and T\({}_{\rm r}\) vs. A for each crop revealed slightly lower relations (R\({}^{2}\) between 0.56 and 0.63, \(p\)-value \(<\) 0.001). These correlations between physiological traits suggest adequate and regular plant behavior inside the growth chamber (Figure S3). Coefficients of determination were relatively high between ET and h\({}_{\rm c}\) for both crops, which is reasonable due to the increases in LAI over time. Maize A, g\({}_{\rm s}\), and T\({}_{\rm r}\) also correlated with h\({}_{\rm c}\), in agreement with the ANOVA (Table 3), showing that variations in leaf physiology were significant across time. Figure 3: Comparison between soil water levels: wet/control (100% Water Holding Capacity, WHC), mid (70% WHC), and dry (40% WHC) for each crop: soybean (blue boxes) and maize (dashed reddish boxes) canopy evapotranspiration (ET), leaf transpiration (T\({}_{\rm r}\)), leaf photosynthesis (A), and leaf conductance (g\({}_{\rm s}\)). Dots in maize and crosses in soybean represent the seasonal average of the six replicates for each crop. Boxplots contain six replicates. Boxes show the 25 th and 75 th percentiles of the interquartile range (IQR), horizontal line represents the median of the data and whiskers extend from the edges of box to show 1.96 IQR. Points outside this range are outliers.