Table 10.

Maize yield increases in large versus small plots, by soil phosphorus concentration level under inoculation with P. bilaiae, 2005–10

	Large plots		Small plots
Phosphorus level	n	Yield increase (t/ha ± s.e.)	n	Yield increase (t/ha±s.e.)
Very low	35	0·33 ± 0·09	5	0·32 ± 0·110
Low	48	0·31 ± 0·08	7	0·21 ± 0·093
Medium	18	0·30 ± 0·13	4	−0·11 ± 0·123
High	16	0·00 ± 0·14	2	n/a
P-value (Prob > F)	0·187		0·004