Continuous planting under a high density enhances the competition for nutrients among young Cunninghamia lanceolata saplings

Table 4 The parameters calculated from A-C _i and A-light curves and PNUE and PPUE values in C. lanceolata as affected by a high planting density under soils that were first (control) and continuously planted with Chinese fir (rotation)

Soils	Planting density	L _CP (μmol m⁻² s⁻¹)	Г (μmol mol⁻¹)	A _max (μmol m⁻² s⁻¹)	V _cmax (μmol m⁻² s⁻¹)	J _max (μmol m⁻² s⁻¹)	V _TPU (μmol mol⁻¹ s⁻¹)	g_m (mol m⁻² s⁻¹)	Φ (μmol μmol⁻¹)	PNUE (μmol g⁻¹ s⁻¹)	PPUE (μmol g⁻¹ s⁻¹)
Control	Low	27.33 ± 1.15 a	97.14 ± 7.42 b	9.76 ± 0.39 b	52.58 ± 2.27 a	52.43 ± 2.10 a	6.39 ± 0.30 a	0.08 ± 0.00 c	0.06 ± 0.01 c	8.33 ± 0.49 b	125.30 ± 7.05 c
Control	High	49.16 ± 3.95 b	119.94 ± 6.78 c	7.84 ± 0.32 a	44.12 ± 4.89 a	45.24 ± 4.68 a	7.23 ± 0.57 a	0.07 ± 0.00 bc	0.03 ± 0.00 a	5.78 ± 0.38 a	80.16 ± 5.22 ab
Rotation	Low	26.84 ± 1.32 a	89.36 ± 6.88 a	9.22 ± 0.64 b	57.97 ± 4.35 a	57.91 ± 4.42 a	7.88 ± 0.56 a	0.06 ± 0.00 b	0.05 ± 0.00 bc	8.23 ± 0.51 b	95.26 ± 5.96 b
Rotation	High	45.91 ± 2.38 b	111.33 ± 8.17 bc	6.17 ± 0.65 a	45.12 ± 7.70 a	45.71 ± 7.93 a	6.67 ± 0.95 a	0.04 ± 0.00 a	0.04 ± 0.00 ab	4.39 ± 0.34 a	67.95 ± 5.77 a
	P _S	0.457	0.543	0.047	0.544	0.575	0.480	0.023	0.482	0.093	0.001
	P _D	0.000	0.003	0.000	0.053	0.078	0.773	0.034	0.000	0.000	0.000
	P _{S × D}	0.583	0.321	0.293	0.676	0.636	0.124	0.432	0.058	0.153	0.155

Each value is the mean ± SE (n = 8). Within a column, values followed by different letters are significantly different at P < 0.05 according to Tukey’s test
P _S soil effect, P _D density effect, P _{S × D} soil and density interaction effect

ISSN: 1297-966X