. 2002 Dec;90(6):745–753. doi: 10.1093/aob/mcf260

Table 2.

N₂‐fixation and net photosynthesis in white clover plants grown under different long‐term steady‐state P treatments controlled by the relative daily addition rate of P

				Ratio net
Relative addition rate (g P g^–1 P d^–1)	N₂‐fixation* (µmol N₂ g^–1 root f. wt h^–1)	Net photosynthesis (µmol CO₂ m^–2 shoot surface area s^–1)	Net photosynthesis (µmol CO₂ s^–1 on total shoot basis)	photosynthesis : N₂‐fixation (mmol CO₂ µmol^–1 N₂ )	Specific leaf area (cm g^–1 DM)
0·03	3·02 (0·21)^a	10·6 (2·2)^a	0·47 (0·09)^a	302 (86)^a	103 (6 )^a
0·06	3·50 (0·08)^a	9·4 (0·7)^a	0·58 (0·05)^a	158 (14)^ab	134 (6)^b
0·10	4·68 (0·53)^b	8·1 (0·5)^a	0·59 (0·06)^a	94 (14)^b	142 (4)^b

Values are means of four observations (± s.e.). Different superscripts within a column indicate differences on a 5 % level.

* Nodules were mistakenly not separated from the roots, thus N₂‐fixation could not be calculated on a nodule basis.