Variations in the natural 13 C and 15 N abundance of plants and soils under long-term N addition and precipitation reduction: interpretation of C and N dynamics

Forest Ecosystems

Table 1 Effect of different treatments, plant species, sample types and their interaction on C concentration, N concentration, δ¹³C and δ¹⁵N plant and soil

		δ¹⁵N value	N concentration	δ¹³C value	C concentration
Treatments	F value	73.02	4.39	7.21	3.94
Treatments	P value	< 0.001	< 0.001	< 0.001	< 0.001
Plant species	F value	94.90	269.25	98.44	16.83
Plant species	P value	< 0.001	< 0.001	< 0.001	< 0.001
Sample types	F value	1992.63	843.83	493.79	2604.86
Sample types	P value	< 0.001	< 0.001	< 0.001	< 0.001
T × P	F value	7.94	8.97	5.02	9.12
T × P	P value	< 0.001	< 0.001	< 0.001	< 0.001
T × S	F value	20.99	6.75	4.43	6.00
T × S	P value	< 0.001	< 0.001	< 0.001	< 0.001
S × P	F value	29.95	66.54	22.62	9.00
S × P	P value	< 0.001	< 0.001	< 0.001	< 0.001
T × P × S	F value	10.88	4.31	3.71	4.63
T × P × S	P value	< 0.001	< 0.001	< 0.001	< 0.001

T × P represents interaction of treatments and plant species; T × S represents interaction of treatments and sample types; S × P represents interaction of sample types and plant species; T × P × S represents interaction of treatments, sample types and plant species