TABLE 1.

Significance (p values) of fixed effect coefficients for statistical models shown in Equations (1‐10) in the results text.

Response variable	${\beta }_{\mathrm{N}}$ *	${\beta }_{\mathrm{I}}$	${\beta }_{{\mathrm{N}}_{\mathit{dfa}}}$	${\beta }_{\mathrm{P}}$	${\beta }_{\mathrm{A}}$	${\beta }_{\mathrm{S}}$	${\beta }_{\ln \left(\mathrm{B}\right)}$	${\beta }_{\mathrm{N}\times \mathrm{I}}$	${\beta }_{\mathrm{N}\times \mathrm{N}\mathit{dfa}}$	${\beta }_{\mathrm{N}\times \mathrm{A}}$	${\beta }_{\mathrm{N}\times \mathrm{S}}$	${\beta }_{\mathrm{P}\times \mathrm{I}}$	${\beta }_{\mathrm{P}\times \mathrm{N}\mathit{dfa}}$	${\beta }_{\mathrm{P}\times \mathrm{A}}$	${\beta }_{\mathrm{P}\times \mathrm{S}}$
Barnard rhizobial tree total biomass (mg)	<.0001	−.3524	.0007	<.0001				.5382	.2562			.3675	.8908
UC Davis rhizobial tree total biomass (mg)	<.0001	−.4806	<.0001	−.5156				−.6476	<.0001			−.9726	−.9429
UC Davis actinorhizal tree total biomass (mg)	<.0001	−.0221	<.0001	.7550				−.0647	.0005			−.3095	.3689
UC Davis soybean total biomass (mg)	<.0001	.2621	.0003	.7206				.5705	.1668			.4393	−.0635
Barnard belowground biomass (% of total)	–<.0001	−.2912	−.0004	−.0319			.6313	.1326	.9895			−.3804	.5563
UC Davis belowground biomass (% of total)	–<.0001	−.2507	–<.0001	.1004	−.5905	−.1020	.0007	.0276	.4508	.4903	.7675	−.6748	−.7671	.7125	−.6717
Barnard foliar biomass (% of aboveground)	.2204	−.0309	<.0001	.4359			–<.0001	.3546	.4387			−.5832	−.9277
UC Davis foliar biomass (% of aboveground)	.3659	.7126	<.0001	−.0072	.0927	−.4011	–<.0001	−.2320	−.0024	.3818	<.0001	.2767	.7729	.4661	−.8535
Barnard nodule biomass (% of belowground)	–<.0001			.0196			<.0001
UC Davis nodule biomass (% of belowground)	–<.0001			.5898	−.1123	−.1859	.8672			.0066	.4276			−.3690	−.8777

^* p values are shown as negative when the effect is negative. p values are shown in bold when they are <.05 and in italics when they are between .05 and .1. The coefficient names correspond to driver variables N (N supplied as fertilizer), I (inoculation), N _dfa (the fraction of the plant's N from fixation), P (P supplied as fertilizer), A (actinorhizal tree as opposed to rhizobial tree), S (soybean as opposed to rhizobial tree), ln(B) (the natural logarithm of biomass), and interactions between some pairs of these variables.