Appendix B. A table showing ANOVA results for (a) fixed and (b) random effects and (c) slicing tests results of the effect of agricultural management system and predator manipulation treatments on Aphis glycines within large field cages at the Kellogg Biological Station Long Term Ecological Research site, Michigan, USA, 2003.
a) Full model with fixed effects
df |
F |
P |
|
Agricultural treatment |
2, 10 |
5.56 |
0.0237 |
Predator treatment |
2, 27 |
94.63 |
< 0.0001 |
Agricultural treat. × predator treat. |
4, 27 |
2.50 |
0.0661 |
Date |
1, 42 |
644.46 |
< 0.0001 |
Agricultural treat × date |
2, 42 |
0.55 |
0.5827 |
Predator treat × date |
2, 42 |
1.47 |
0.2424 |
Agricultural treat. × predator treat. × date |
4, 42 |
0.65 |
0.6278 |
b) Random effects
Estimate |
Z |
P |
|
Block |
0.090 ± 0.071 |
1.25 |
0.1053 |
Agricultural treat × block |
0.006 ± 0.033 |
0.19 |
0.4248 |
Agricultural treat × predator treat × block |
0.094 ± 0.048 |
1.97 |
0.0427† |
Residual |
0.143 ± 0.031 |
||
† Graphical exploration of the significant 3-way interaction revealed consistently higher number of aphids on the exclusion cages in comparison with open and sham cages within each agronomic treatment and block. Therefore, predator manipulation effects were not affected by the 3-way interaction. However, the number of aphids obtained in the exclusion cages for each agronomic treatment varied in different blocks, showing an inconsistent effect of agronomic treatment in this experiment.
c) Slicing tests for significant interaction terms of fixed effects
Agricultural treat. × predator treat. |
df |
F |
P |
Conventional |
2, 27 |
49.07 |
< 0.0001 |
No-till |
2, 27 |
36.20 |
< 0.0001 |
Zero-chemical input |
2, 27 |
17.03 |
< 0.0001 |
Predator exclusion |
2, 27 |
1.43 |
0.2572 |
Sham |
2, 27 |
8.28 |
0.0016 |
Open |
2, 27 |
2.03 |
0.1508 |