Results from the fitting of dynamics of SPAD readings to a piecewise function.

<p>The letters a<sub>1</sub>, c, and a<sub>2</sub> represent function coefficients as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088421#pone-0088421-g006" target="_blank">Fig. 6</a>. N1, N2, N3, N4, N5, and N6 indicate N application rates of 0, 75, 150, 225, 300, and 375 kg N ha<sup>−1</sup>, respectively.</p><p><sup>***</sup><i>P</i> <0.001.</p>