Table 6. Effects of different tillage depths on photosynthetic characteristics of rice at grain filling stage.

Treatment	Pn (μmolCO2·m−2s−1)	Cond (μmol H2O·m−2s−1)	Ci (μmolCO2·m−2s−1)	Trmmol (mmol.m−2s−1)
TD14	13.39b	0.64a	315.93a	5.28a
TD17	15.01a	0.62a	310.25ab	5.32a
TD20	15.86a	0.61a	306.43b	5.36a
TD23	15.45a	0.57a	304.28b	5.28a
Y	ns	ns	ns	ns
TD	*	ns	**	ns
Y*TD	ns	ns	ns	ns

Note:

Different letters in the same row within the same rice means the significant differences in P < 0.05. * and ** indicate significant correlations at the 0.05 and 0.01 levels. TD, tillage depth; TD14, tillage depth 14 cm; TD17, tillage depth 17 cm; TD20, tillage depth 20 cm; TD 23, tillage depth 23 cm; ; Y, year; Pn, photosynthetic rate; Cond, stomatal conductance; Ci, transpiration rate; Trmmol, intercellular carbon dioxide concentration.