Table 3.
Inter-annual variability in maize yield (2005–11) under inoculation with P. bilaiae, in the small plot trials, 2005–10. Yield increase (%) is for inoculated crop relative to control (not inoculated)
| Year | N | Yield (t/ha ± s.e.) | Range | Yield increase (% ±s.e.) | 95% CI* | I† v. C‡ (t/ha ± s.e.) | Paired t-test | Z-test (C‡ v. I†) |
|---|---|---|---|---|---|---|---|---|
| 2005 | 10 | 10·1 ± 0·77 | 6·4–13·3 | 0·72 ± 0·729 | −0·9 to 2·4 | 0·05 ± 0·081 | <0·28 | 0·190 |
| 2006 | 9 | 11·2 ± 0·84 | 7·8–14·3 | 1·81 ± 1·131 | −0·8 to 4·4 | 0·15 ± 0·117 | <0·11 | 0·094 |
| 2007 | 23 | 8·4 ± 0·26 | 6·9–10·8 | 3·26 ± 1·047 | 1·1 to 5·4 | 0·28 ± 0·085 | <0·00 | 0·001 |
| 2008 | 24 | 10·6 ± 0·44 | 7·3–16·2 | 0·62 ± 0·838 | −1·1 to 2·4 | 0·05 ± 0·084 | <0·28 | 0·280 |
| 2009 | 11 | 13·7 ± 0·52 | 10·4–15·6 | 3·67 ± 0·731 | 2·0 to 5·3 | 0·48 ± 0·080 | <0·00 | <0·001 |
| 2010 | 15 | 12·6 ± 0·57 | 8·5–15·4 | 0·68 ± 0·745 | −0·9 to 2·7 | 0·08 ± 0·103 | <0·22 | 0·212 |
*
Confidence interval.
†
Control.
‡
Inoculated.