Response of Soil Respiration to Grazing in an Alpine Meadow at Three Elevations in Tibet

Table 2

Repeated-measures analysis of variance for the main and interactive effects of grazing (G) and sampling date (D) on dissolved organic C (DOC, mg kg⁻¹) and N (DON, mg kg⁻¹), the ratio of DOC and DON (DOC/DON ratio), nitrate N (NO₃⁻-N, mg kg⁻¹), ammonium N (NH₄⁺-N, mg kg⁻¹), the ratio of NH₄⁺-N and NO₃⁻-N (NH₄⁺-N/NO₃⁻-N ratio), soil available N (SAN, mg kg⁻¹), and belowground root biomass (BGB, kg m⁻²) in an alpine meadow at three elevations (i.e., 4313 m, 4513 m, and 4693 m) on the Tibetan Plateau (𝑛=4).

Elevation	Model	DOC	DON	DOC/DON ratio	NO3^−-N	NH4^+-N	NH4^+-N/NO3^−-N ratio	SAN	BGB
4313 m	G	0.77	1.65	0.46	27.10**	26.05**	1.05	95.61***	0.00
	D	26.25***	4.80*	5.00*	57.55***	10.47**	8.95**	29.95***	2.79
	G × D	2.64	1.46	0.29	11.02**	3.00	2.16	7.13*	1.45
4513 m	G	0.00	2.23	5.51	7.29*	13.99**	0.04	16.50**	1.52
	D	35.53***	4.38*	0.40	51.70***	29.87***	12.29***	57.31***	2.74
	G × D	3.15	3.81	3.49	1.85	2.05	0.51	3.07	0.98
4693 m	G	0.00	0.16	0.12	0.82	0.27	0.08	0.65	0.64
	D	1.33	3.67	3.03	9.24**	15.27***	0.94	15.78***	3.85
	G × D	3.41	1.24	0.04	1.79	6.95**	0.30	5.67*	0.95

 *, **, and ***means 𝑃<0.05, 𝑃<0.01, and 𝑃<0.001, respectively.