TABLE 2.

Nodulation parameters^a

Parameter	Nonamended soil (mean ± SD)		Leaf litter-amended soilb (mean ± SD)		Effects of leaf litter amendment and inoculation (P)c
	Noninoculatedd	Inoculatede	Noninoculatedd	Inoculatede	Inoculation	Leaf-litter
No. of lobes	21 ± 13	31 ± 15	20 ± 13	80 ± 28	<0.001	<0.001
Total lobe weight (mg [fresh wt.])	160 ± 76	149 ± 82	169 ± 68	165 ± 42	0.879	0.652
Average lobe weight (mg [fresh wt.])	9 ± 5	5 ± 1	10 ± 4	2 ± 1	<0.001	0.239
Group IIIa (probe 23ArI3)	93 ± 16	32 ± 23	0	8 ± 6	<0.001	<0.001
Group IV [probe 23Mut15(II)]	0	51 ± 20	89 ± 12	81 ± 11	0.015	<0.001
Group I [probe 23B1.9(II)]	0	0	0	0
Lobes without frankiaee	7 ± 16	17 ± 14	11 ± 12	11 ± 13	0.153	0.957

^aAveraged parameters (± standard deviation) were obtained after 4 months of growth. 

^bSoil “Ettiswil” mixed with dried alder leaves to a final concentration of 1%. 

^cStatistical analysis was performed using two-way ANOVA, and corresponding P values are shown. 

^dSoil “Ettiswil”. 

^eSoil “Ettiswil” inoculated with Frankia strains ArI3, Ag45/Mut15 and AgB1.9, each at a density of approximately 10⁷ cells g of soil⁻¹ (fresh wt.).