Maize Growth and Soil Properties

Soil Management and Conservation Project

Project overview

Five soil-management treatments (TA, TB, TC, TD, and TE) were evaluated in five blocks in a maize experiment. Plant height, leaf number, and stem width were measured weekly.

The scientific poster presents the main growth panel and the week 8 summary table. This supplementary report provides all figures, statistical comparisons, soil results, and model diagnostics.

Main results included in the poster

Growth during the eight-week evaluation

Figure 4. Growth trajectories of maize during the evaluation. Points represent treatment means, and error bars represent the standard error calculated from five blocks.

Week 8 growth summary

Table 1. Descriptive summary of maize growth measurements in week 8.

Individual growth trajectories

Plant height

Figure 1. Weekly maize height growth. Treatment differences became more evident during the final weeks of evaluation.

Leaf number

Figure 2. Weekly change in leaf number. All treatments reached 11 leaves.

Stem width

Figure 3. Weekly stem-width growth during the evaluation.

Final statistical comparisons

Final plant height

Figure 5. Maize height at the end of week 8 of measurement. Colored points represent blocks, black diamonds represent adjusted means, vertical bars represent 95% confidence intervals, and letters represent Tukey groups. TA was significantly shorter than TB, TC, TD, and TE.

Final stem width

Figure 6. Stem width at the end of week 8 of measurement. TA had significantly lower stem width than TC and TD. TB and TE showed intermediate responses.

Soil chemical properties

Figure 7. Descriptive comparison of soil chemical properties by treatment. Colors show the relative position of each treatment within each soil property, while the numbers are laboratory values.

Only one soil sample was analyzed per treatment; therefore, no statistical inference was performed for soil properties.

Supplementary statistical diagnostics

Supplementary Figure 1. Diagnostic plots for the final-height ANOVA. These plots were used to assess residual behavior, approximate normality, variance consistency, and potentially influential observations.

The diagnostic plots identified observation 21 as the largest negative residual. This observation was retained unless a field-record error could be demonstrated.

Main statistical findings

Final plant height differed significantly among treatments ((F_{4,16} = 6.37), (p = 0.0029)). TA produced significantly shorter plants than TB, TC, TD, and TE, whereas the latter four treatments did not differ significantly from one another.

Final stem width also differed significantly among treatments ((F_{4,16} = 5.85), (p = 0.0043)). TA had significantly lower stem width than TC and TD, while TB and TE had intermediate responses.

All treatments reached 11 leaves, resulting in no observable variation for a final-week statistical comparison.

Conclusion

Treatments significantly affected maize plant height and stem width. TA showed the lowest final vegetative growth. Although TD and TE presented high numerical values, neither treatment was statistically superior to all other treatments. Soil chemical properties differed descriptively among treatments, but the absence of soil replication prevented statistical inference.