Chlorophyll concentration (g m<sup>−2</sup>), chlorophyll a/b ratio, N concentration (<i>N</i><sub>a</sub>, g m<sup>−2</sup>), and leaf thickness (µm) of the four uppermost leaves of rice plants from three plots not subjected to N application.

<p>Each value is an average of 30 measurements. Within a column, values followed by different letters are significantly different at <i>P</i> <0.05 according to Duncan’s multiple range test. Dates of sampling were DAT 75 in 2008 and DAT 77 in 2009.</p>