Table 3.

Grey Correlation Analysis on contents of N and P between organs of P. australis and different depth of soil.

Depth of soil	Association index								Association index of N and P between the whole plant and different depth of soil
	Winter		Spring		Summer		Autumn
	N	P	N	P	N	P	N	P	N	P
0–15	0.30	0.40	0.30	0.54	0.51	0.72	0.25	0.25	0.71	0.65
≥15–30	0.35	0.40	0.25	0.45	0.45	0.66	0.35	0.25	0.68	0.66
≥30–45	0.43	0.36	0.25	0.45	0.52	0.64	0.33	0.25	0.67	0.65
≥45–60	0.41	0.33	0.26	0.62	0.41	0.70	0.25	0.25	0.64	0.65
Seasonal association index of N and P between the whole plant and soil	0.37	0.37	0.27	0.52	0.47	0.68	0.30	0.25