IMPACTS OF GRAZING ON SOIL CARBON FRACTIONS IN THE GRASSLANDS OF XILIN RIVER BASIN, INNER MONGOLIA

doi:10.17521/cjpe.2005.0076

Abstract

Abstract:

Inner Mongolia grasslands are an important ecosystem of the Euro-Asia plateau. However, in recent decades, it has been severely degraded due to overgrazing, and, at the same time, soil carbon storage has changed. Because of the high background variation and diversity of natural soils, it is difficult to detect changes in soil carbon pools, especially over short time periods. Some experiments have attempted to detect changes in different fractions of soil carbon pools. In Inner Mongolia grasslands, experiments have showed there was no evident decrease of soil organic carbon for grazing. In this study, we examined the effects of grazing on soil carbon fractions: soil microbial carbon (MB-C) and soil labile carbon (Lab-C) in the grasslands of the Xilin River Basin of Inner Mongolia. MB-C was determined using the chloroform fumigation method and Lab-C was determined using the potassium permanganate oxidation method. The results indicated that after 22 years of grazing in Leymus chinensis dominated grasslands. Soil microbial biomass decreased by 27.9% and 12.8% in the 0-10 cm and 10-20 cm layers, respectively, and Lab-C decreased by 22.0% and 12.6% in the two soil layers. After 22 years of grazing in a Stipa grandis grassland, MB-C decreased by 38.2% and 12.2% in the 0-5 cm and 5-15 cm soil layers, respectively. The time at which soil microbial biomass reached a peak in S. grandis was delayed (August) as compared to L. chinensis, and MB-C was significantly correlated with aboveground grass biomass (p<0.000 1). Soil microbial carbon and Lab-C were more sensitive than SOC to the impacts of grazing on changes in soil carbon storage. There were no significant decreases in any of the soil carbon fractions in theArtemisia frigida+short bunchgrasses grassland with increases in the stocking rates, but the ratios of MB-C/total C and Lab-C/total C decreased gradually with increases in stocking rates. These results indicate that the ratios of MB-C/total C and Lab-C/total C are more sensitive indicators than MB-C and Lab-C in reflecting soil carbon changes under grazing pressure in the Artemisia frigida+short bunchgrasses grassland.

Key words: Grazing, Soil carbon fractions, Inner Mongolia Grasslands

MA Xiu-Zhi, WANG Yan-Fen, WANG Shi-Ping, WANG Jin-Zhi, LI Chang-Sheng. IMPACTS OF GRAZING ON SOIL CARBON FRACTIONS IN THE GRASSLANDS OF XILIN RIVER BASIN, INNER MONGOLIA[J]. Chin J Plant Ecol, 2005, 29(4): 569-576.

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https://www.plant-ecology.com/EN/Y2005/V29/I4/569

Figures/Tables 6

References 31

[1]	Blair BJ, Lefroy RD (1995). Soil carbon fractions based on their degree of oxidation, and the developments of a carbon management index for agriculture systems. Australian Journal of Agriculture Research, 46,1456-1466.
[2]	Bauer JD, Armand CV, Black AL (1987). Soil property comparisons in virgin grasslands between grazed land non-grazed management systems. Soil Science Society of America Journal, 51,176-182.
[3]	Biederbeck BO, Zentner RP (1994). Labile soil organic matter as influenced by cropping practices in an arid environment. Soil Boilogy and Biochemistry, 26,1647-1656.
[4]	Cui XY, Wang YF, Niu HS, Wang SP, Schnag E, Rogasik J, Flecenstein J, Tang YH (2005). Effect of long-term grazing on soil organic carbon content in semiarid steppe in Inner Mongolia. Ecological Research, 20, DOI: 10.1007/S11284-005-0063-8.
[5]	Derner JD, Beriske DD, Boutton TW (1997). Dose grazing mediate soil carbon and accumulation beneath C₄,perennial grasses along an environmental gradient? Journal of Range Management, 24,308-309.
[6]	Elzein A, Balesdent J (1995). A mechanistic simulation of the vertical distribution of carbon concentrations and residence time in soil. Soil Science Society of America Journal, 59,1328-1335.
[7]	Frank AB, Tanaka DL, Hofmann L, Follett RF (1995). Soil carbon and nitrogen of Northern Great Plains grasslands as influenced by long-term grazing. Journal of Range Management, 48,470-474.
[8]	Graetz D (1994). Grasslands. In: Meyer BL, Turner WB eds. Changes in Land-Use and Land-Cover: a Global Perspective. Cambridge University Press, Cambridge UK, 125.
[9]	Holt JA (1997). Grazing pressure and soil carbon, microbial biomass and enzyme activities in semi-arid northeastern Australia. Journal of Applied Soil Ecology, 5,143-149.
[10]	Houghton RA(1995). Changes in the storage of terrestrial carbon since 1850.In:Lai R ed. Soils and Global Change. CRC Press, Inc, Roca Raton,Florida,45-65.
[11]	IPCC (2001). The Third Evaluation Report:Climate Change, Synthesis Report. Cambridge University Press, Cambridge.8-10.
[12]	Jenkinson DS, Powlson DS (1976). The effects of biocidal treatments on metabolism in soil — a method for measuring soil biomass. Soil Biology and Biochemistry, 8,189-202.
[13]	Jenkinson DS, Odes JM (1979). A method for measuring adenosine in soil. Soil Biology and Biochemistry, 11,193-199.
[14]	Keeling CD (1997). Climate change and carbon dioxide. An introduction National Academy of Science, 94,8273-8274.
[15]	Li XZ(李香真), Chen ZZ(陈佐忠) (1998). Impacts of plant and soil C,N,P contents on different stocking rate. Acta Agrestia Sinica (草地学报), 16,90-98. (in Chinese with English abstract)
[16]	Li LH(李凌浩) (1998). Effects of land-use change on soil carbon storage in grassland ecosystems. Acta Phytoecologica Sinica (植物生态学报), 22,300-302. (in Chinese with English abstract)
[17]	Lin QM(林启美), Wu YG(吴玉光) (1999). Modification of fumigation extraction method for measuring soil microbial biomass carbon. Chinese Journal of Ecology (生态学杂志), 18(2),63-66. (in Chinese with English abstract)
[18]	Lefory RDB, Blair GJ, Strong WM (1993). Changes in soil organic matter with cropping as measured by organic carbon and ¹³C natural isotope abundance. Plant and Soil,155-156,399-402.
[19]	Mazzarino MJ, Szott L, Jimenez M (1993). Dynamics of soil total C and N, microbial biomass,and water-soluble C in tropical agroecosystems. Soil Biology and Biochemistry, 25,205-214.
[20]	Marumoto TJ, Domsch KH (1982). Mineration of nutrients from soil microbial biomass. Soil Biology and Biochemistry, 14,469-475.
[21]	Moondy HA, Vitousek PM, Matson PA (1987). Exchange of material between terrestrial ecosystem and the atmosphere. Science, 238,926-932.
[22]	Milchunas DG, Lauenroth WK (1993). Quantitative effects of grazing on vegetation and soil over a global range of environments. Ecological Monographs, 63,327-366.
[23]	Sampson RN, Apps M, Brown S (1993). Terrestrial biosphere carbon fluxes quantification of sinks and sources of CO₂. Water Air and Soil Pollution, 70,3-15.
[24]	Sparling GP, West AW (1989). Importance of soil water content when estimating soil microbial C、N and P by the fumigation-extraction methods. Soil Biology & Biochemistry, 21,245-253.
[25]	Schuman GE, Reeder JD, Manley JT, Hart RH, Manley WA (1999). Impact of grazing management on the carbon and nitrogen balance of a mixed-grass rangeland. Ecological Applications, 9,65-71.
[26]	Wang YF(王艳芬), Chen ZZ(陈佐忠), Tieszen LT (1998). Distribution of soil organic carbon in the major grasslands of Xilingole,Inner Mongolia, China. Acta Phytoecologica Sinica (植物生态学报), 22,545-551. (in Chinese with English abstract)
[27]	Wang SP(王淑平), Zhou GS(周广胜), Gao SH(高素华), Guo JP(郭建平) (2003). Distribution of soil labile carbon along the Northeast transect (NECT) and its response to climate change. Acta Phytoecologica Sinica (植物生态学报), 27,780-785. (in Chinese with English abstract)
[28]	Watson RT, Verardo DJ (2000). Land-Use Change and Forestry. Cambridge University Press, Cambridge.
[29]	Weinhold BJ, Henndrickson JR, Karn JF (2001). Pasture management influences on soil properties in the Northern Grain plains. Journal of Soil and Water Conservation, 56,27-31.
[30]	Wolters V, Joergensen RG (1993). Microbial biomass and its contribution to nutrient concentrations in forest soils. Soil Biology and Biochemistry, 25,25-31.
[31]	XU YC(徐阳春), Shen QR(沈其荣) (2002). Impacts on soil microbial C, N,P under long-term no-till and organic manure spreading. Acta Pedologica Sinica (土壤学报), 39,89-95. (in Chinese with English abstract)

土层 Soil layer	羊草草原 Leymus chinensis grassaland		大针茅草原 Stipa grandis grassland		冷蒿-小禾草草原 Artemisia frigida-short bunchgrass steppe
土层 Soil layer	围封 Enclosure	自由放牧 Grazing	围封 Enclosure	自由放牧 Grazing	轻牧 LG	中牧 MG	重牧 HG
表层 Top layer (g·kg^-1)	390.4±59.9	281.4±54.6	496.2±70.7	306.5±54.2	356.3±30.4	347.7±18.7	355.4±34.9
下层 Sub layer (g·kg^-1)	230.9±37.4	201.3±40.4	321.9±64.8	282.7±13.8	209.4±28.4	161.5±21.5	191.1±26.8
(T-S)/T(%)	0.8	28.4	35.1	7.8	41.2	53.5	46.2

土层 Soil layer	羊草草原 Leymus chinensis grassaland		大针茅草原 Stipa grandis grassland		冷蒿-小禾草草原 Artemisia frigida-short bunchgrass steppe
土层 Soil layer	围封 Enclosure	自由放牧 Grazing	围封 Enclosure	自由放牧 Grazing	轻牧 LG	中牧 MG	重牧 HG
表层 Top layer (g·kg^-1)	390.4±59.9	281.4±54.6	496.2±70.7	306.5±54.2	356.3±30.4	347.7±18.7	355.4±34.9
下层 Sub layer (g·kg^-1)	230.9±37.4	201.3±40.4	321.9±64.8	282.7±13.8	209.4±28.4	161.5±21.5	191.1±26.8
(T-S)/T(%)	0.8	28.4	35.1	7.8	41.2	53.5	46.2

土层 Soil layer	羊草草原 Leymus chinensis grassalnd		冷蒿-小禾草草原 Artemisia frigida-short bunchgrasses steppe
土层 Soil layer	围封 Enclosure	自由放牧 Grazing	轻牧 LG	中牧 MG	重牧 HG
表层 Top layer 0~10 cm	4.49±0.29	3.50±0.62	2.93±0.66	2.65±0.13	2.71±0.08
下层 Sub layer 10~20 cm	2.61±0.57	2.28±0.52	1.46±1.26	1.21±0.37	1.12±0.25
(T-S)/T(%)	41.8	34.9	50.2	54.3	58.7

土层 Soil layer	羊草草原 Leymus chinensis grassalnd		冷蒿-小禾草草原 Artemisia frigida-short bunchgrasses steppe
土层 Soil layer	围封 Enclosure	自由放牧 Grazing	轻牧 LG	中牧 MG	重牧 HG
表层 Top layer 0~10 cm	4.49±0.29	3.50±0.62	2.93±0.66	2.65±0.13	2.71±0.08
下层 Sub layer 10~20 cm	2.61±0.57	2.28±0.52	1.46±1.26	1.21±0.37	1.12±0.25
(T-S)/T(%)	41.8	34.9	50.2	54.3	58.7