Nitrogenase activity (Acetylene reduction activity in nmol C<sub>2</sub>H<sub>2</sub> g<sup>−1</sup> h<sup>−1</sup>) in response to additions of P to soils from six forest sites (mean (s.e.m.); <i>n</i> = 5.
<p>Nitrogenase activity (Acetylene reduction activity in nmol C<sub>2</sub>H<sub>2</sub> g<sup>−1</sup> h<sup>−1</sup>) in response to additions of P to soils from six forest sites (mean (s.e.m.); <i>n</i> = 5.</p