青藏高原高寒草地土壤碳矿化及其温度敏感性

doi:10.3724/SP.J.1258.2013.00102

摘要/Abstract

摘要：

青藏高原具有独特的海拔、气候和生态系统类型, 弄清其土壤有机质分解及其温度敏感性对于揭示青藏高原土壤碳储量变化及其碳汇功能具有重要意义。该文利用青藏高原西北部草地的11个封育-自由放牧成对草地, 通过测定不同温度(5、10、15、20和25 ℃)培养下的土壤碳矿化速率, 探讨了土地利用方式对该地区土壤碳矿化及其温度敏感性的影响。实验结果表明: 温度对青藏高原高寒草地的土壤碳矿化具有显著影响, 温度越高土壤碳矿化量越大。从东至西, 土壤碳矿化量逐渐降低。草地土壤碳矿化量与土壤有机碳和土壤全氮含量显著正相关; 即土壤有机碳和土壤全氮含量越高, 土壤碳矿化量就越高。土地利用方式对土壤碳矿化的温度敏感性(Q₁₀)无显著影响, Q₁₀值变化范围为1.4-2.4; 其中, 放牧草地Q₁₀的平均值为1.83, 封育草地Q₁₀的平均值为1.86。此外, Q₁₀与土壤有机碳和土壤全氮含量无显著的相关关系, 也无明显的空间格局。放牧和封育对青藏高原高寒草地土壤碳矿化的温度敏感性无显著影响, 为深入分析青藏高原土壤碳汇功能及其对未来气温升高的响应提供了重要的理论依据。

关键词: 土地利用方式, Q₁₀, 青藏高原, 土壤有机质, 空间格局, 温度敏感性

Abstract:

Aims Currently, the temperature sensitivity of soil carbon (C) mineralization and the factors that control it are the focus of studies on soil C cycle and global climate change. The main objectives of this study were to: (1) investigate the effects of temperature and land-use (fenced grassland vs. grazing grassland) on soil C mineralization and its temperature sensitivity (Q₁₀) in the grasslands of Qinghai-Xizang Plateau and (2) determine the relationships of the rate of soil C mineralization with soil properties (e.g. soil organic carbon content (SOC), soil total nitrogen content (STN)).
Methods Eleven pairs of plots (fenced sites vs. grazing sites) were selected along an east-west transect in northwest of Qinghai-Xizang Plateau. Soil samples were collected at a depth of 0-20 cm, to measure soil C mineralization rates under a temperature gradient (i.e. 5, 10, 15, 20, and 25 °C) in laboratory. Data for soil C mineralization rate on the 7th day and 56th day, respectively, were used to assess the short- and long-term effects.
Important findings Soil C mineralization rates declined from east to west on fenced sites, but varied slightly on the grazing sites. Soil C mineralization rates increased significantly with increasing incubation temperature, and were strongly related to SOC and STN; higher the SOC and STN, greater the accumulative soil C mineralization. Q₁₀ showed no apparent spatial pattern along the east-west transect, and was not susceptible to land-use with average Q₁₀values of 1.83 and 1.86 on the fenced sites and the grazing sites, respectively. Moreover, Q₁₀ was not correlated with either SOC or STN. Findings in this study provide new insights on the responses of soil C mineralization and its temperature sensitivity to land-use change on the Qinghai-Xizang Plateau, contributing important information for evaluating soil C sequestration and its response to warming scenarios in this region.

Key words: land use type, Q₁₀, Qinghai-Xizang Plateau, soil organic matter, spatial pattern, temperature sensitivity

徐丽,于书霞,何念鹏,温学发,石培礼,张扬建,代景忠,王若梦. 青藏高原高寒草地土壤碳矿化及其温度敏感性. 植物生态学报, 2013, 37(11): 988-997. DOI: 10.3724/SP.J.1258.2013.00102

XU Li,YU Shu-Xia,HE Nian-Peng,WEN Xue-Fa,SHI Pei-Li,ZHANG Yang-Jian,DAI Jing-Zhong,WANG Ruo-Meng. Soil C mineralization and temperature sensitivity in alpine grasslands of the Qinghai-Xizang Plateau. Chinese Journal of Plant Ecology, 2013, 37(11): 988-997. DOI: 10.3724/SP.J.1258.2013.00102

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链接本文: https://www.plant-ecology.com/CN/10.3724/SP.J.1258.2013.00102

https://www.plant-ecology.com/CN/Y2013/V37/I11/988

图/表 8

参考文献 36

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实验样点 Experimental site	封育草地 Fenced grassland (FG)		自由放牧草地 Grazing grassland (GG)
实验样点 Experimental site	经度 Longitude (E)	纬度 Latitude (N)	经度 Longitude (E)	纬度 Latitude (N)
样点1 Site 1	91.973 1°	31.383 5°	91.962 4°	31.376 4°
样点2 Site 2	91.723 8°	31.619 2°	91.719 8°	31.608 2°
样点3 Site 3	91.907 8°	32.302 9°	91.910 5°	32.305 0°
样点4 Site 4	90.459 8°	31.364 4°	90.399 0°	31.374 5°
样点5 Site 5	90.055 3°	31.497 4°	90.055 6°	31.497 8°
样点6 Site 6	90.244 1°	31.391 1°	90.244 4°	31.391 4°
样点7 Site 7	86.653 3°	32.337 9°	86.653 6°	32.338 2°
样点8 Site 8	86.796 9°	31.752 9°	86.797 2°	31.753 2°
样点9 Site 9	85.839 5°	31.924 6°	85.840 0°	31.924 9°
样点10 Site 10	82.910 0°	32.380 9°	82.910 6°	32.381 2°
样点11 Site 11	81.828 2°	32.074 8°	81.828 4°	32.075 3°

实验样点 Experimental site	封育草地 Fenced grassland (FG)		自由放牧草地 Grazing grassland (GG)
实验样点 Experimental site	经度 Longitude (E)	纬度 Latitude (N)	经度 Longitude (E)	纬度 Latitude (N)
样点1 Site 1	91.973 1°	31.383 5°	91.962 4°	31.376 4°
样点2 Site 2	91.723 8°	31.619 2°	91.719 8°	31.608 2°
样点3 Site 3	91.907 8°	32.302 9°	91.910 5°	32.305 0°
样点4 Site 4	90.459 8°	31.364 4°	90.399 0°	31.374 5°
样点5 Site 5	90.055 3°	31.497 4°	90.055 6°	31.497 8°
样点6 Site 6	90.244 1°	31.391 1°	90.244 4°	31.391 4°
样点7 Site 7	86.653 3°	32.337 9°	86.653 6°	32.338 2°
样点8 Site 8	86.796 9°	31.752 9°	86.797 2°	31.753 2°
样点9 Site 9	85.839 5°	31.924 6°	85.840 0°	31.924 9°
样点10 Site 10	82.910 0°	32.380 9°	82.910 6°	32.381 2°
样点11 Site 11	81.828 2°	32.074 8°	81.828 4°	32.075 3°

实验样点 Experimental site	优势植被 Dominant vegetation	土地利用方式 Land-use type	有机碳含量 Organic carbon content (g·kg^-1)	全氮含量 Total nitrogen content (g·kg^-1)	pH
样点1 Site 1	高山嵩草	封育草地 Fenced grassland	19.04 ± 0.04^a	1.52 ± 0.02^a	8.04 ± 0.12^a
	Kobresia pygmaea	自由放牧草地 Grazing grassland	10.30 ± 0.01^b	0.94 ± 0.01^b	8.33 ± 0.36^a
样点2 Site 2	高山嵩草	封育草地 Fenced grassland	24.42 ± 0.08^a	1.91 ± 0.03^a	8.56 ± 0.52^a
	K. pygmaea	自由放牧草地 Grazing grassland	13.31 ± 0.02^b	1.21 ± 0.08^b	7.77 ± 0.48^a
样点3 Site 3	高山嵩草	封育草地 Fenced grassland	11.76 ± 0.01^a	1.05 ± 0.00^a	8.43 ± 0.05^a
	K. pygmaea	自由放牧草地 Grazing grassland	11.12 ± 0.01^b	1.13 ± 0.01^b	7.78 ± 0.41^a
样点4 Site 4	紫花针茅	封育草地 Fenced grassland	12.27 ± 0.03^a	1.18 ± 0.03^a	7.79 ± 0.57^a
	Stipa purpurea	自由放牧草地 Grazing grassland	10.23 ± 0.01^b	1.09 ± 0.03^b	8.38 ± 0.19^a
样点5 Site 5	紫花针茅和羊草	封育草地 Fenced grassland	10.31 ± 0.09^a	1.04 ± 0.04^a	9.07 ± 0.02^a
	S. purpurea and Leymus chinensis	自由放牧草地 Grazing grassland	8.92 ± 0.07^a	1.14 ± 0.05^b	8.53 ± 0.55^a
样点6 Site 6	紫花针茅	封育草地 Fenced grassland	8.96 ± 0.06^a	0.97 ± 0.01^a	7.83 ± 0.30^a
	S. purpurea	自由放牧草地 Grazing grassland	12.17 ± 0.03^b	1.21 ± 0.03^b	8.33 ± 0.22^a
样点7 Site 7	紫花针茅	封育草地 Fenced grassland	6.40 ± 0.16^a	0.71 ± 0.04^a	9.94 ± 0.01^a
	S. purpurea	自由放牧草地 Grazing grassland	3.95 ± 0.06^b	0.70 ± 0.03^a	10.09 ± 0.02^b
样点8 Site 8	紫花针茅	封育草地 Fenced grassland	13.36 ± 0.13^a	2.14 ± 0.05^a	8.73 ± 0.03^a
	S. purpurea	自由放牧草地 Grazing grassland	10.14 ± 0.13^b	1.39 ± 0.08^b	8.53 ± 0.03^b
样点9 Site 9	紫花针茅和薹草	封育草地 Fenced grassland	6.70 ± 0.31^a	0.99 ± 0.03^a	9.28 ± 0.03^a
	S. purpurea and Carex moorcroftii	自由放牧草地 Grazing grassland	6.91 ± 0.10^a	1.03 ± 0.09^a	8.94 ± 0.04^b
样点10 Site 10	沙生针茅和羽状针茅	封育草地 Fenced grassland	17.40 ± 0.13^a	1.23 ± 0.05^a	8.62 ± 0.09^a
	S. purpurea and S. pennata	自由放牧草地 Grazing grassland	11.89 ± 0.16^b	0.94 ± 0.02^b	8.82 ± 0.03^b
样点11 Site 11	沙生针茅和羽状针茅	封育草地 Fenced grassland	3.76 ± 0.31^a	0.59 ± 0.06^a	9.12 ± 0.01^a
	S. purpurea and S. pennata	自由放牧草地 Grazing grassland	6.55 ± 0.17^a	0.79 ± 0.06^b	9.05 ± 0.03^b

实验样点 Experimental site	优势植被 Dominant vegetation	土地利用方式 Land-use type	有机碳含量 Organic carbon content (g·kg^-1)	全氮含量 Total nitrogen content (g·kg^-1)	pH
样点1 Site 1	高山嵩草	封育草地 Fenced grassland	19.04 ± 0.04^a	1.52 ± 0.02^a	8.04 ± 0.12^a
	Kobresia pygmaea	自由放牧草地 Grazing grassland	10.30 ± 0.01^b	0.94 ± 0.01^b	8.33 ± 0.36^a
样点2 Site 2	高山嵩草	封育草地 Fenced grassland	24.42 ± 0.08^a	1.91 ± 0.03^a	8.56 ± 0.52^a
	K. pygmaea	自由放牧草地 Grazing grassland	13.31 ± 0.02^b	1.21 ± 0.08^b	7.77 ± 0.48^a
样点3 Site 3	高山嵩草	封育草地 Fenced grassland	11.76 ± 0.01^a	1.05 ± 0.00^a	8.43 ± 0.05^a
	K. pygmaea	自由放牧草地 Grazing grassland	11.12 ± 0.01^b	1.13 ± 0.01^b	7.78 ± 0.41^a
样点4 Site 4	紫花针茅	封育草地 Fenced grassland	12.27 ± 0.03^a	1.18 ± 0.03^a	7.79 ± 0.57^a
	Stipa purpurea	自由放牧草地 Grazing grassland	10.23 ± 0.01^b	1.09 ± 0.03^b	8.38 ± 0.19^a
样点5 Site 5	紫花针茅和羊草	封育草地 Fenced grassland	10.31 ± 0.09^a	1.04 ± 0.04^a	9.07 ± 0.02^a
	S. purpurea and Leymus chinensis	自由放牧草地 Grazing grassland	8.92 ± 0.07^a	1.14 ± 0.05^b	8.53 ± 0.55^a
样点6 Site 6	紫花针茅	封育草地 Fenced grassland	8.96 ± 0.06^a	0.97 ± 0.01^a	7.83 ± 0.30^a
	S. purpurea	自由放牧草地 Grazing grassland	12.17 ± 0.03^b	1.21 ± 0.03^b	8.33 ± 0.22^a
样点7 Site 7	紫花针茅	封育草地 Fenced grassland	6.40 ± 0.16^a	0.71 ± 0.04^a	9.94 ± 0.01^a
	S. purpurea	自由放牧草地 Grazing grassland	3.95 ± 0.06^b	0.70 ± 0.03^a	10.09 ± 0.02^b
样点8 Site 8	紫花针茅	封育草地 Fenced grassland	13.36 ± 0.13^a	2.14 ± 0.05^a	8.73 ± 0.03^a
	S. purpurea	自由放牧草地 Grazing grassland	10.14 ± 0.13^b	1.39 ± 0.08^b	8.53 ± 0.03^b
样点9 Site 9	紫花针茅和薹草	封育草地 Fenced grassland	6.70 ± 0.31^a	0.99 ± 0.03^a	9.28 ± 0.03^a
	S. purpurea and Carex moorcroftii	自由放牧草地 Grazing grassland	6.91 ± 0.10^a	1.03 ± 0.09^a	8.94 ± 0.04^b
样点10 Site 10	沙生针茅和羽状针茅	封育草地 Fenced grassland	17.40 ± 0.13^a	1.23 ± 0.05^a	8.62 ± 0.09^a
	S. purpurea and S. pennata	自由放牧草地 Grazing grassland	11.89 ± 0.16^b	0.94 ± 0.02^b	8.82 ± 0.03^b
样点11 Site 11	沙生针茅和羽状针茅	封育草地 Fenced grassland	3.76 ± 0.31^a	0.59 ± 0.06^a	9.12 ± 0.01^a
	S. purpurea and S. pennata	自由放牧草地 Grazing grassland	6.55 ± 0.17^a	0.79 ± 0.06^b	9.05 ± 0.03^b

样点 Site	培养7天		培养56天
	Incubation for 7 d		Incubation for 56 d
	D 值	p值	D 值	p值
	D value	p value	D value	p value
	(μg C·g^-1soil)		(μg C·g^-1soil)
样点1 Site 1	25.92	0.023	148.99	0.012
样点2 Site 2	39.38	0.02	218.41	0.018
样点3 Site 3	-0.63	0.8	-41.79	0.091
样点4 Site 4	7.68	0.008	50.23	0.011
样点5 Site 5	9.96	0.003	70.45	0.006
样点6 Site 6	-9.81	0.01	-85.59	0.003
样点7 Site 7	1.7	0.047	31.94	0.123
样点8 Site 8	3.75	0.325	69.53	0.005
样点9 Site 9	5.75	0.064	58.81	0.009
样点10 Site 10	15.86	0	63.21	0.009
样点11 Site 11	-8.36	0.024	-80.58	0.012