Table 4.
Analysis of variance from mixed model procedures for (A) weed control efficiency (%) at 12 WAP, (B) cassava stand population at crop harvest, (C) cassava stem and (D) root yields as influenced by location and post-emergence treatment, their interactions and all treatments contrasted with farmer practice in 2016 and 2017 in on-farm trials in Nigeria.
| Variables |
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (A) Weed control efficiency (%) at 12 WAP |
(B) Cassava stand population at crop harvest (no. ha−1) |
(C) Cassava stem yield (kg ha−1) |
(D) Cassava fresh roots yield (kg ha−1) |
||||||||||
| Source of variation | df | DDF | F | Pr>F | DDF | F | Pr>F | DDF | F | Pr>F | DDF | F | Pr>F |
| 2016 | |||||||||||||
| Location (L) | 3 | 19 | 8.16 | 0.0001 | 20 | 2.36 | 0.1025 | 19 | 6.8 | 0.0027 | 20 | 4.68 | 0.0124 |
| Pre-emergence (Pr) | 6 | 114 | 20.68 | <.0001 | 969 | 0.96 | 0.4490 | 920 | 13.54 | <.0001 | 969 | 21.34 | <.0001 |
| Post-emergence (Ps) | 7 | 931 | 98.04 | <.0001 | 969 | 5.67 | <.0001 | 920 | 8.05 | <.0001 | 969 | 13.18 | <.0001 |
| Pr × Ps | 42 | 931 | 22.63 | <.0001 | 969 | 1.85 | 0.0009 | 920 | 1.38 | 0.0553 | 969 | 2.62 | <.0001 |
| L × Pr | 18 | 114 | 1.44 | 0.1283 | 969 | 0.1 | 1.0000 | 920 | 1.45 | 0.1005 | 969 | 1.02 | 0.4358 |
| L × Ps | 21 | 931 | 5.77 | <.0001 | 969 | 2.03 | 0.0040 | 920 | 1.04 | 0.4078 | 969 | 2.49 | 0.0002 |
| L × Pr × Ps | 126 | 931 | 2.07 | <.0001 | 969 | 1.27 | 0.0308 | 920 | 1.18 | 0.0984 | 969 | 1.07 | 0.2994 |
| Treateda vs Farmer's practice | 1 | NC | NC | NC | 969 | 16.16 | <0.0001 | 920 | 51.41 | <0.0001 | 969 | 78.50 | <0.0001 |
| 2017 | |||||||||||||
| Location (L) | 3 | 176 | 1.2 | 0.3124 | 111 | 0.280 | 0.8432 | 107 | 19.02 | <.0001 | 111 | 3.53 | 0.0172 |
| Preemergence (Pr) | 5 | 184 | 0.52 | 0.7640 | 184 | 0.070 | 0.9963 | 176 | 1.38 | 0.2348 | 184 | 4.50 | 0.0007 |
| Postemergence (Ps) | 4 | 184 | 9.1 | <.0001 | 184 | 2.690 | 0.0324 | 176 | 1.10 | 0.3562 | 184 | 1.57 | 0.1842 |
| Pr × Ps | 20 | 184 | 1.07 | 0.3857 | 184 | 0.390 | 0.9921 | 176 | 0.73 | 0.7873 | 184 | 1.68 | 0.0406 |
| L × Pr | 15 | 184 | 0.44 | 0.9658 | 184 | 0.040 | 1.0000 | 176 | 2.54 | 0.0020 | 184 | 0.80 | 0.6742 |
| L × Ps | 12 | 184 | 1.45 | 0.1486 | 184 | 0.710 | 0.7367 | 176 | 0.93 | 0.5146 | 184 | 1.31 | 0.2161 |
| L × Pr × Ps | 60 | 184 | 1.2 | 0.1805 | 184 | 0.740 | 0.9099 | 176 | 0.51 | 0.9985 | 184 | 0.88 | 0.7170 |
| Treated vs Farmer's practice | 1 | 184 | 45.43 | <0.0001 | 184 | 3.13 | 0.0784 | 176 | 11.62 | 0.0008 | 184 | 37.34 | <0.0001 |
a
Treated refers to all pre- and post-emergence treatments. df, numerator degree of freedom; DDF, denominator degree of freedom of covariance parameter. The level of significance was set at P < 0.05 probability level. NC = Data were not collected in farmer practice plots in 2016.