青藏高原东北缘高寒草甸土壤养分、微生物量碳氮及氮矿化潜力的研究
|
摘要
青藏高原因海拔高和气候寒冷,被认为是气候变化的敏感区和脆弱区。随着全球气候变化的影响,土壤微生物量(SMB)、土壤中氮(N)的矿化将可能受到强烈影响,这些影响将可能使土壤中活性有机质、有效氮含量和植物生长速率改变,进而将对高寒草甸植被的生产力和碳汇功能产生一定的影响。尽管对多数陆地环境中的土壤养分、SMB和N矿化做过不少调查研究,但针对青藏高原的研究仍然较少。为了探讨青藏高原东北缘高寒草甸草地土壤养分和微生物量碳(Cmic)氮(Nmic)等指标的变化,我们研究了土地利用方式对土壤养分和SMB的影响,不同放牧强度对该区SMB和N矿化潜力的影响,以及土壤Cmic和Nmic在不同海拔梯度的分布状态,同时将室内培养下土壤N矿化潜力与野外原地培养净N矿化进行了比较。主要研究结果如下：
1.对三类不同土地利用方式(自然草地、弃耕约10年的土地以及耕作至少50年以上的土地)下土壤养分及SMB的分析显示：与自然草地相比,耕作50年后的土壤有机碳(SOC)和全氮(TN)分别损失了45%和43%；而与耕作地相比,弃耕约10年后的SOC和TN分别升高了27%和23%。耕地中的SMB和微生物基础呼吸(MR)较低。弃耕地中的Cmic含量介于耕地和自然草地,而弃耕地中的Nmic含量和MR与自然草地的差异不显著。由此可见：在青藏高原东北缘的高寒草甸草地上,持续的耕作降低了土壤养分和SMB,提高了微生物代谢熵(qCO2)；而在该区域采取弃耕和对天然草地进行保护对土壤质量的恢复和维持是有效的措施。
2.通过对青藏高原东北缘高寒草甸四类放牧强度(围栏封育/无放牧、轻度、适度和重度放牧)下的SOC、TN、Cmic和Nmic、矿化N的测量分析得出：SOC和TN对放牧的反应不敏感；而适度的放牧明显促进了微生物对碳氮元素的累积和固定。同时Cmic/SOC和Nmic/TN比值作为土壤有机碳/全氮向微生物碳/氮转化效率的指标,也是在适度放牧区最高。这证明在该研究地区,对草地进行合理的管理能促进土壤活性C库和N库的丰富度。
3.作为土壤质量的检测指标之一,土壤N矿化潜力在围栏封育区最高,而在重度放牧区最低,这与SOC和TN的变化规律一致,但比后两者的变化更明显。进一步表明适当的围栏封育利于土壤质量的恢复和/或者保持,而重度放牧降低了土壤质量。
4.通过对位于青藏高原东北缘高寒草甸5个海拔梯度(从低到高依次为3050m、3180m、3570m、3600m和3910m)的土壤理化特性、Cmic和Nmic、室内室外培养的净N矿化的研究得知：土壤Cmic在各海拔间差异不显著；而Nmic,微生物量碳、氮分别对土壤有机碳和全氮的贡献率(Cmic/SOC和Nmic/TN)在不同海拔间差异显著(p<0.05),且均与海拔梯度呈显著负相关(相关系数分别为-0.464、-0.806和-0.680),说明低海拔地区有较多的营养被微生物固定,潜在的有效营养源较高。
5.Cmic和Nmic均随土壤pH值的降低而减少,是由于细菌适宜于中性或微碱性的环境(低海拔土壤pH值变化范围为6.7-7.1,土壤为中性),而高海拔土壤(pH变化范围为5.2-5.7)的酸性环境抑制了该研究地区以细菌为主导的微生物群落的活性,从而导致高海拔区微生物固定的C、N量较低。而Cmic和Nmic与土壤水分含量呈负相关(p>0.05),说明过多的水分导致土壤含氧量降低,从而对微生物活性产生抑制作用。
6.室内培养的N矿化速率大于野外原位培养净N矿化率,说明在室内控制的适宜的温度和湿度(22℃和40-60%的田间持水量)条件下,矿化速率较高,进一步说明虽然高海拔气候环境恶劣,但其土壤潜在的可矿化、可利用的养分仍然较高。
Although the researches about the soil nutrients, the immobilization of C and N in microbes and N mineralization have been investigated in many terrestrial environments, the similar research on the Tibetan Plateau is scarce. To better understand the dynamics of the soil nutrients and microbial biomass on the Tibetan plateau, we analyzed the effect of land-use management (natural grassland, abandoned old-field and crop field) on soil physiochemical properties and microbial biomass (SMB); investigated the effects of fencing and grazing on the microbial biomass carbon (Cmic) and nitrogen (Nmic), and mineralized N in soils at four sites with different grazing intensity:no-grazing (fencing), light-, moderate-and heavy-grazing of an alpine meadow on the northeastern Tibetan plateau. At the same time, we analyzed the distribution of Cmic and Nmic from sites at 5 different altitudes (3050, 3180,3570,3600,3910 m), the relationships among them and soil properties, and compared the net N mineralization rate both from indoor-and in-situ incubation. The results showed:
1. The losses of SOC and TN were about 45% and 43%, respectively, due to cultivation after more than 50 years comparing with natural grassland. Because of the abandonment of cultivation for about a decade, SOC and TN were increased by 27% and 23%, respectively, in comparison with the crop field. Microbial carbon (ranging from 357.5 to 761.6 mg kg-1 soil) in the old-field was intermediate between the crop field and grassland. Microbial nitrogen (ranging from 29.9 to 106.7 mg kg-1 soil) and respiration (ranging from 60.4 to 96.4 mg CO2-Cg-1Cmic d-1) were not significantly lower in the old-field than those in the grassland. Thus it could be concluded that cultivation decreased the soil organic matter and SMB, while the adoption of abandonment has achieved some targets of grassland restoration in the alpine region of Gansu Province on the northeastern Tibetan plateau.
2. The effect of grazing on soil nutrients was not statistically significant, while moderate grazing markedly stimulated the accumulation and immobilization of C and N in microbes. As a good measure of the efficiency of soil nutrients conversion into microbial C and N, Cmic/SOC and Nmic/TN were higher in the moderate-grazing site, which demonstrated that proper management of grassland promoted enrichment of the available soil C and N pool in the study area.
3. As a measure of soil quality, N mineralization potential was higher in the fencing site and lower in the heavy-grazing site, showing the similar trend with SOC and TN, which demonstrated that the fencing is beneficial to the restoration and/or maintenance of soil quality, while the heavy grazing reduces soil quality.
4. There was no significant difference for Cmic among different altitudes; but significant differences for Nmic, Cmic/SOC and Nmic/TN were detected among different altitudes, and the latter three had a significantly negative correlation with elevation, which demonstrated that the microbes fixed more and effective potential nutrition in the low altitude.
5. There was a significantly positive correlation between soil pH and microbial biomass (p<0.01):The bacteria adapt to the neutral or slightly alkaline environment (pH in the low-altitude ranges from 6.7 to 7.1, the neutral soil), while the acidic soil environment of high-elevation (pH ranges from 5.2 to 5.7) maybe suppress the activity of bacteria-dominated microbial communities, which caused less C and N fixed by microbes in high-altitude. There was a negative correlation between soil moisture and microbial biomass (p>0.05), which was because too much water led to reduced oxygen, thus inhibited microbial activity in the soil.
6. The net N mineralization from the indoor incubation was larger than that from the in-situ incubation, which indicated that there would be higher N mineralization rates under the conditions with appropriate temperature and moisture.
1.对三类不同土地利用方式(自然草地、弃耕约10年的土地以及耕作至少50年以上的土地)下土壤养分及SMB的分析显示：与自然草地相比,耕作50年后的土壤有机碳(SOC)和全氮(TN)分别损失了45%和43%；而与耕作地相比,弃耕约10年后的SOC和TN分别升高了27%和23%。耕地中的SMB和微生物基础呼吸(MR)较低。弃耕地中的Cmic含量介于耕地和自然草地,而弃耕地中的Nmic含量和MR与自然草地的差异不显著。由此可见：在青藏高原东北缘的高寒草甸草地上,持续的耕作降低了土壤养分和SMB,提高了微生物代谢熵(qCO2)；而在该区域采取弃耕和对天然草地进行保护对土壤质量的恢复和维持是有效的措施。
2.通过对青藏高原东北缘高寒草甸四类放牧强度(围栏封育/无放牧、轻度、适度和重度放牧)下的SOC、TN、Cmic和Nmic、矿化N的测量分析得出：SOC和TN对放牧的反应不敏感；而适度的放牧明显促进了微生物对碳氮元素的累积和固定。同时Cmic/SOC和Nmic/TN比值作为土壤有机碳/全氮向微生物碳/氮转化效率的指标,也是在适度放牧区最高。这证明在该研究地区,对草地进行合理的管理能促进土壤活性C库和N库的丰富度。
3.作为土壤质量的检测指标之一,土壤N矿化潜力在围栏封育区最高,而在重度放牧区最低,这与SOC和TN的变化规律一致,但比后两者的变化更明显。进一步表明适当的围栏封育利于土壤质量的恢复和/或者保持,而重度放牧降低了土壤质量。
4.通过对位于青藏高原东北缘高寒草甸5个海拔梯度(从低到高依次为3050m、3180m、3570m、3600m和3910m)的土壤理化特性、Cmic和Nmic、室内室外培养的净N矿化的研究得知：土壤Cmic在各海拔间差异不显著；而Nmic,微生物量碳、氮分别对土壤有机碳和全氮的贡献率(Cmic/SOC和Nmic/TN)在不同海拔间差异显著(p<0.05),且均与海拔梯度呈显著负相关(相关系数分别为-0.464、-0.806和-0.680),说明低海拔地区有较多的营养被微生物固定,潜在的有效营养源较高。
5.Cmic和Nmic均随土壤pH值的降低而减少,是由于细菌适宜于中性或微碱性的环境(低海拔土壤pH值变化范围为6.7-7.1,土壤为中性),而高海拔土壤(pH变化范围为5.2-5.7)的酸性环境抑制了该研究地区以细菌为主导的微生物群落的活性,从而导致高海拔区微生物固定的C、N量较低。而Cmic和Nmic与土壤水分含量呈负相关(p>0.05),说明过多的水分导致土壤含氧量降低,从而对微生物活性产生抑制作用。
6.室内培养的N矿化速率大于野外原位培养净N矿化率,说明在室内控制的适宜的温度和湿度(22℃和40-60%的田间持水量)条件下,矿化速率较高,进一步说明虽然高海拔气候环境恶劣,但其土壤潜在的可矿化、可利用的养分仍然较高。
Although the researches about the soil nutrients, the immobilization of C and N in microbes and N mineralization have been investigated in many terrestrial environments, the similar research on the Tibetan Plateau is scarce. To better understand the dynamics of the soil nutrients and microbial biomass on the Tibetan plateau, we analyzed the effect of land-use management (natural grassland, abandoned old-field and crop field) on soil physiochemical properties and microbial biomass (SMB); investigated the effects of fencing and grazing on the microbial biomass carbon (Cmic) and nitrogen (Nmic), and mineralized N in soils at four sites with different grazing intensity:no-grazing (fencing), light-, moderate-and heavy-grazing of an alpine meadow on the northeastern Tibetan plateau. At the same time, we analyzed the distribution of Cmic and Nmic from sites at 5 different altitudes (3050, 3180,3570,3600,3910 m), the relationships among them and soil properties, and compared the net N mineralization rate both from indoor-and in-situ incubation. The results showed:
1. The losses of SOC and TN were about 45% and 43%, respectively, due to cultivation after more than 50 years comparing with natural grassland. Because of the abandonment of cultivation for about a decade, SOC and TN were increased by 27% and 23%, respectively, in comparison with the crop field. Microbial carbon (ranging from 357.5 to 761.6 mg kg-1 soil) in the old-field was intermediate between the crop field and grassland. Microbial nitrogen (ranging from 29.9 to 106.7 mg kg-1 soil) and respiration (ranging from 60.4 to 96.4 mg CO2-Cg-1Cmic d-1) were not significantly lower in the old-field than those in the grassland. Thus it could be concluded that cultivation decreased the soil organic matter and SMB, while the adoption of abandonment has achieved some targets of grassland restoration in the alpine region of Gansu Province on the northeastern Tibetan plateau.
2. The effect of grazing on soil nutrients was not statistically significant, while moderate grazing markedly stimulated the accumulation and immobilization of C and N in microbes. As a good measure of the efficiency of soil nutrients conversion into microbial C and N, Cmic/SOC and Nmic/TN were higher in the moderate-grazing site, which demonstrated that proper management of grassland promoted enrichment of the available soil C and N pool in the study area.
3. As a measure of soil quality, N mineralization potential was higher in the fencing site and lower in the heavy-grazing site, showing the similar trend with SOC and TN, which demonstrated that the fencing is beneficial to the restoration and/or maintenance of soil quality, while the heavy grazing reduces soil quality.
4. There was no significant difference for Cmic among different altitudes; but significant differences for Nmic, Cmic/SOC and Nmic/TN were detected among different altitudes, and the latter three had a significantly negative correlation with elevation, which demonstrated that the microbes fixed more and effective potential nutrition in the low altitude.
5. There was a significantly positive correlation between soil pH and microbial biomass (p<0.01):The bacteria adapt to the neutral or slightly alkaline environment (pH in the low-altitude ranges from 6.7 to 7.1, the neutral soil), while the acidic soil environment of high-elevation (pH ranges from 5.2 to 5.7) maybe suppress the activity of bacteria-dominated microbial communities, which caused less C and N fixed by microbes in high-altitude. There was a negative correlation between soil moisture and microbial biomass (p>0.05), which was because too much water led to reduced oxygen, thus inhibited microbial activity in the soil.
6. The net N mineralization from the indoor incubation was larger than that from the in-situ incubation, which indicated that there would be higher N mineralization rates under the conditions with appropriate temperature and moisture.
引文
1. Abril A, Bucher EH. Overgrazing and soil carbon dynamics in the western Chaco of Argentina. Applied Soil Ecology,2001.16:243-249.
2 Almeida FL, Cassia de PM, Josefine FB, Clemente CC, Pellegrino CCE. Inorganic nitrogen, microbial biomass and microbial activity of a sandy Brazilian Cerrado soil under different land uses. Agriculture, Ecosystems & Environment,2010.135 (3):161-167.
3. Alvarez R, Alvarez CR. Soil organic matter pools and their associations with C mineralization kinetics. Soil Science Society of America Journal.2000.64:184-189.
4. Ananyeva ND, Demkina TS, Jones WJ, Cabrera ML, Steen WC. Microbial biomass in soils of Russia under long-term management practices. Biology & Fertility of Soils,1999.29: 291-299.
5. Anderson TH, Domsch KH. Carbon link between microbial biomass and soil organic matter. In:Megusar F.& Gantar M. (eds.) Proceedings of the Fourth International Symposium, Microbial Ecology Soc Microbial Lujbljana,1986. pp.467-471.
6. Anderson TH, Domsch KH. Application of eco-physiological quotients (qCO2 and qD) on microbial biomasses from soils of different cropping histories. Soil Biology & Biochemistry, 1990.22:251-255.
7. Anderson TH, Domsch KH. The matobolic quotient for CO2 (qCO2) as a specific activity parameter to assess the microbial biomass of forest soils. Soil Biology & Biochemistry, 1993a.25:393-395.
8. Anderson TH, Domsch KH. The metabolic quotient for CO2 (qCO2) as a specific activity parameter to assess the effects of environmental conditions, such as pH, on the microbial biomass of forest soils. Soil Biology & Biochemistry,1993b.22:251-255.
9. Arvidsson J. Influence of soil texture and organic matter content on bulk density, air content, compression index and crop yield and laboratory compression experiments. Soil & Tillage Research,1998.4:159-170.
10. Bardgett RD, Leemans DK. The short-term effects of cessation of fertilizer applications, liming and grazing on microbial biomass and activity in a reseeded upland grassland soil.
Biology & Fertility of Soils,1995.19:148-154.
11. Bardgett RD, Leemans DK, Cook R, Hobbs P J. Seasonality in the soil biota of grazed and ungrazed hill grasslands. Soil Biology & Biochemistry,1997.2:1285-1294.
12 Bardgett RD, Wardle DA, Yeates GW. Linking above-ground and below-ground interactions: how plant responses to foliar herbivory influence soil organisms. Soil Biology & Biochemistry 1998.30:1867-1878.
13. Baron VS, Mapfumo E, Dick AC, Naeth MA, Okine EK, Chanasyk DS. Grazing intensity impacts on pasture carbon and nitrogen flow. Journal of Range Management,2002.55: 535-541.
14. Bauer A, Cole CV, Black AL. Soil property comparisons in virgin grasslands between grazed and no-grazed management systems. Soil Science Society of American Journal,1987.51: 176-182.
15. Brookes PC. The use of microbial parameters in monitoring soil pollution by heavy metals. Biology & Fertility of Soils,1995.19:269-279.
16. Carter MR. Microbial biomass and mineralizable N in Solonetzic soils:Influence of gypsum and time amendments. Soil Biology & Biochemistry,1986.18:531-537.
17. Carter MR. Soil quality for sustainable management:organic matter and aggregation indicators that maintain soil functions. Agronomy Journal,2002.94:38-47.
18. Castillo VM, Mena MM, Albaladejo J. Runoff and soil loss response to vegetation removal in a semiarid environment. Soil Science Society of America Journal,1997.61:1071-1076.
19. Celik I. Land-use effects on organic matter and physical properties of soil in a southern Mediterranean highland of Turkey. Soil & Tillage Research,2005.83:270-277.
20. Charles T, Garten J, Paul JH. Measured forest soil C stocks and estimated turnover times along an elevation gradient. Geoderma,2006.136:342-352.
21. Chen Y, Tang H. Desertification in north China:background, anthropogenic impacts and failures in combating it. Land Degradation & Development,2005.16:367-376.
22. Coffin DP, Laycock WA, Lauenroth WK. Disturbance intensity and above-and below-ground herbivory effects on long-tern (14 years) recovery of a semi-arid grassland. Plant Ecology,1998.139:221-233.
23. Cui XY, Wang YF, Niu HS, Wu J, Wang SP, Schnug E, Rogasik J, Fleckenstein J, Tang YH. Effect of long-term grazing on soil organic carbon content in semiarid steppes in Inner Mongolia. Ecological Research,2005.20:519-527.
24. Dakhah M, Gifford GF. Influence of vegetation, rock cover and tramp ling on infiltration rates and sediment production. Water Resource Bulletin,1980.16:979-986.
25. Davidson EA, Matson PA, Vitousek PM, Riley R, Dunkin K, Garciamendez G, Maass JM. Processes regulating soil emissions of NO and N2O in a seasonally dry tropical forest. Ecology,1993.74:130-139.
26. Deenik J. Nitrogen mineralization potential in important agricultural soils of Hawai'i. Soil Crop Management,2006.15:1-5.
27. Dendooven L, Merckx R, Vlassak K. Limitations of a calculated N mineralization potential in studies of the N mineralization process. Plant & Soil,1995.177:175-181.
28. Derner JD, Beriske DD, Boutton TW. Does grazing mediate soil carbon and nitrogen accumulation beneath C4, perennial grasses along an environmental gradient? Plant & Soil, 1997.191:147-156.
29. Derner JD, Boutton TW, Briske DD. Grazing and ecosystem carbon storage in the North American Great Plains. Plant & Soil,2006.280:77-90.
30. Devi BV, Yadava PS. Seasonal dynamics in soil microbial biomass C, N and P in a mixed-oak forest ecosystem of Manipur, Northeast India. Applied Soil Ecology,2006.31:220-227.
31. Diaz-Ravina M, Acea MJ, Carballas T. Seasonal changes in microbial biomass and nutrient flush in forest soils. Biology & Fertility of Soils,1995.19:220-226.
32 Dilly O, Blume HP, Sehy U, Jimenez M, Munch JC. Variation of stabilized, microbial and biologically active carbon and nitrogen in soil under contrasting land use and agricultural management practices. Chemosphere,2003.52:557-569.
33. Dilly O, Munch JC. Ratios between estimates of microbial biomass content and microbial activity in soils. Biology & Fertility of Soils,1998.27:374-379.
34. Dube F, Zagal E, Stolpe N, Espinosa M. The influence of land-use change on the organic carbon distribution and microbial respiration in a volcanic soil of the Chilean Patagonia. Forest Ecology & Management,2009.257:1695-1704.
35. Frank AB, Liebig MA, Tanaka DL. Management effects on soil CO2 efflux in northern semiarid grassland and cropland. Soil&Tillage Research,2006.89:78-85.
36. Frank AB, Tanaka DL, Hofinann L, et al. Soil carbon and nitrogen of Northern Great Plains grasslands as influenced by long-term grazing. Journal of Range Management,1995.48 (5): 470-474.
37. Fu BJ, Liu SL, Lu YH, Chen LD, Ma KM, Liu LH. Comparing the soil quality changes of different land uses determined by two quantitative methods. Journal of Environmental Sciences,2003.15:167-172
38. Gao YH, Luo P, Wu N, Chen H, Wang GX. Grazing intensity impacts on carbon sequestration in an Alpine Meadow on the eastern Tibetan Plateau. Research Journal of Agriculture & Biological Science,2007.3 (6):642-647.
39. Garcia PJ, Casals P, Camarero L, et al. Factors regulating carbon mineralization in the surface and subsurface soils of Pyrenean mountain grasslands. Soil Biology & Biochemistry,2008. 40:2803-2810.
40. Garten CT, Hanson PJ. Measured forest soil C stocks and estimated turnover times along an elevation gradient. Geoderma,2006.136:342-352.
41. Garten CT, Post WM, Hanson PJ, Cooper LW. Forest soil carbon inventories and dynamics along an elevation gradient in the southern Appalachian Mountains. Biogeochemistry,1999. 45:115-145.
42 Grayston SJ, Vaughan D, Jones D. Rhizosphere carbon flow in trees, incomparison with annual plants:the importance of root exudation and its impact on microbial activity and nutrient availability. Applied Soil Ecology,1996.5:29-56.
43. Greenwood KL, MacLeod DA, Hutchinson KJ. Long-term stocking rate effects on soil physical properties. Australian Journal of Experimental Agriculture,1997.37:413-419.
44. Han GD, Hao XY, Zhao ML, Wang MJ, Ellert BH, Water Willms, Wang MJ. Effect of grazing intensity on carbon and nitrogen in soil and vegetation in a meadow steppe in Inner Mongolia. Agriculture Ecosystem & Environment,2008.125:21-32.
45. Hao L, Lal R, Owens LB, Izaurralde RC, Post WM, Hothem DL. Effect of cropland management and slope position on soil organic carbon pool at the North Appalachian Experimental Watersheds. Soil & Tillage Research,2002.68:133-142.
46. Harris D, Voroney RP, Paul EA. Measurement of microbial biomass N:C by chloroform fumigation-incubation. Canadian Journal of Soil Science,1997.77:507-514.
47. Hart SC, Perry DA. Transferring soils from high-to low-elevation forests increases nitrogen cycling rates:climate change implications. Global Change Biology,1999.5:23-32.
48. He ZL, Wu J, O'Donnell AG, Syers JK. Seasonal responses in microbial biomass carbon, phosphorus and sulphur in soils under pasture. Biology & Fertility of Soils,1997.24: 421-428.
49. Hofstede RGM. The effects of grazing and burning on soil and plant nutrient concentrations in Colombia Paramo grasslands. Plant & Soil,1995.173:111-132.
50. Holt JA. Grazing pressure and soil carbon, microbial biomass and enzyme activities in semi-arid northeastern Australia. Applied Soil Ecology,1997.5:143-149.
51. Ineson P, Taylor K, Harrison AF, et al. Effects of climate change on nitrogen dynamics in upland soil.1. A transplant approach. Global Change Biology,1998.4:143-152.
52 Insam H. Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil Biology & Biochemistry,1990.22:525-532.
53. Insam H, Domsch KH. Relationship between soil organic carbon and microbial biomass on chronosequences of the reclamation sites. Microbial Ecology,1988.15:177-188.
54. Islam KR, Weil RR. Land-use effects on soil quality in a tropical forest ecosystem of Bangladesh. Agriculture, Ecosystems & Environment,2000.79:9-16.
55. Jenkinson DS. The determination of microbial biomass carbon and nitrogen in soils. In Wilson JR. (ed.), Advances in Nitrogen Cycling in Agricultural Ecosystems. CAB International, Wallingford; New York,1988. pp.368-386.
56. Jia GM, Cao J, Wang G. Influence of land management on soil nutrients and microbial biomass in the central Loess Plateau, northwest China. Land Degradation & Development, 2005a.16:455-462.
57. Jia GM, Cao J, Wang CY, Wang G. Microbial biomass and nutrients in soil at the different stages of secondary forest succession in Ziwulin, northwest China. Forest Ecology& Management,2005b.217:117-125.
58. Jia S, Li S, Chen Y, Dong H, Guo B. Soil physical properties and water regime in process of grassland degradation and restoration. In:Inner Mongolia Grassland Ecosystem Research Station (ed.), Research on Grassland Ecosystem. Science, Beijing,1997. pp.111-117.
59. Joergensen RG,Scheu S. Depth gradients of microbial and chemical properties in moder soils
under beech and spruce. Pedobiology,1999.43:134-144.
60. Kemmitt SJ, Wright D, Goulding KWT, et al. pH regulation of carbon and nitrogen dynamics in two agricultural soils. Soil Biology & Biochemistry,2006.38:898-911.
61. Killham K. Soil Ecology. Cambridge University Press, Cambridge.1994.
62 Li XG, Li FM, Rengel Z, Zhan ZY, Singh B. Soil physical properties and their relations to organic carbon pools as affected by land use in an alpine pastureland. Geoderma,2007a.139: 98-105.
63. Li XG, Rengel Z, Mapfumo E, Singh B. Increase in pH stimulates mineralization of'native' organic carbon and nitrogen in naturally salt-affected sandy soils. Plant & soil,2007b.290: 269-282.
64. Li Y, Ruan H, Zou X, et al. Response of major soil decomposers to landslide disturbance in a Puerto Rican rainforest. Soil Science,2005.170:202-211.
65. Maithani K, Arunachalam A, Tripathi RS, et al. Nitrogen mineralization as influenced by climate, soil and vegetation in subtropical humid forest in northeast India. Forest Ecology& Management,1998.109:91-101.
66. Malchair S, Carnol M. Microbial biomass and C and N transformations in forest floors under European beech, sessile oak, Norway spruce and Douglas-fir at four temperate forest sites. Soil Biology & Biochemistry,2009.41:831-839.
67. Ma MJ, Zhou XH, Du GZ. Role of soil seed bank along a disturbance gradient in an alpine meadow on the Tibet plateau. Flora,2010.205:128-134.
68. Mazzarino MJ, Bertiller MB, Sain C, et al. Soil nitrogen dynamics in northeastern Patagonia steppe under different precipitation regimes. Plant & Soil,1998.202:125-131.
69. Mazzarino MJ, Szott L, Jimenez M. Dynamics of soil total carbon, nitrogen, microbial biomass and water soluble carbon in tropical agroecosystems. Soil Biology & Biochemistry, 1993.25:205-214.
70. McInnes PF. Effects of moose brow sing on vegetation and litter of the boreal forest. Ecology, 1992.73:2059-2075.
71. McNaughton SJ. Ecology of a grazing ecosystem:the Serengeti. Ecological Monographs, 1985.53:291-320.
72 McNaughton SJ, Ruess RW, Seagle SW. Large mammals and process dynamics in African ecosystems. BioScience,1988.38:794-800.
73. Milchunas DG, Laurenroth WK. Quantitative effects of grazing on vegetation and soils over a global range of environments. Ecological Monographs,1993.63:327-366.
74. Milchunas DG, Laurenroth WK, Burke LC. Livestock grazing:animal and plant biodiversity of short-grass steppe and the relationship to ecosystem functioning. Oikos,1998.83:65-74.
75. Miralles I, Ortega R, Almendros G, Sanchez-Maranon M, Soriao M. Soil quality and organic carbon ratios in mountain agroecosystems of South-east Spain. Geoderma,2009.150: 120-128.
76. Morecroft MD, Marrs RH, Woodward FI. Altitudinal and seasonal trends in soil nitrogen mineralization rate in the Scottish Highlands. Journal of Ecology,1992.80:49-56.
77. Moscatelli MC, Di Tizio A, Marinari S, Grego S. Microbial indicators related to soil carbon in Mediterranean land use systems. Soil Tillage & Research,2007.97:51-59.
78. Mwendera EJ, Mohamed SMA. Infiltration rates, surface runoff, and soil loss as influenced by grazing pressure in Ethiopian highlands. Soil Use & Management,1997.13:29-35.
79. Naeth MA, Bailey AW, Pluth DJ, et al. Grazing impacts on litter and soil organic matter in mixed prairie and fescue grassland ecosystem s of Alberta. Journal of Range Management, 1991.44:7-12.
80. Nannipieri P, Grego S, Ceccanti B. Ecological significance of the biological activity in soil. In:Bollag JM, Stotzky G. (eds.), Soil viochemistry, vol.6. Marcel Dekker, New York, NY, U.S.A.,1990. pp.293-355.
81. Nsabimana D, Haynes RJ, Wallis FM. Size, activity and catabolic diversity of the soil microbial biomass as affected by land use. Applied Soil Ecology,2004.26:81-92.
82 Ocio JA, Brookes PC. An evaluation of methods for measuring microbial biomass in soils following recent additions of wheat straw and the characterization of the biomass that develops. Soil Biology & Biochemistry,1990.22:685-694.
83. Odum E. Trends expected in stressed ecosystems. Bioscience,1985.35:419-422.
84. Ohtsuka T, Hirota M, Zhang XZ, Shimono A, Senga Y, Du MG, Yonemura S, Kawashima S, Tang YH. Soil organic carbon pools in alpine to nival zones along an altitudinal gradient (4400-5300 m) on the Tibetan Plateau. Polar Science,2008.2:277-285.
85. Oldeman LR, Hakkeling RTA, Som broek WG. World map of the status of human-incuded
soil degradation:An explanatory note. In:Wageningen. The Netherlands and Nairobi, Kenya: International Soil Reference and information Center and United Nations Environment Programmer.1991.
86. Paustian K, Six J, Elliott ET, Hunt HW. Management options for reducing CO2 emissions from agricultural soils. Biogeochemistry,2000.48:147-163.
87. Percival HJ, Parfitt RL, Scott NA. Factors controlling soil carbon levels in New Zealand grassland:Is clay content important? Soil Science Society of America Journal,2000.64: 1623-1630.
88. Piao HC, Hong YT, Yuan ZY. Seasonal changes of microbial biomass carbon related to climatic factors in soils from karst areas of southwest China. Biology& Fertility of Soils, 2000.30:294-297.
89. Post WM, Emanuel R, Zinke PJ, et al. Soil carbon pools and world life zones. Nature,1982. 298:156-159.
90. Powlson DS, Brookes PC, Christensen BT. Measurement of soil microbial biomass provides an early indication of changes in total soil organic matter due to straw incorporation. Soil Biology & Biochemistry,1987.19:159-164.
91. Powlson DS, Jenkinson DS. A comparison of the organic matter, biomass, adenosine triphosphate and mineralizable nitrogen contents of ploughed and direct-drilled soils. Journal of Agricultural Science,1981.97:713-721.
92 Prescott CE, Chappell NH, Vesterda L. Nitrogen turnover in forest floors of coastal Douglas fir at sites differing in soil nitrogen capital. Ecology,2000.81:1878-1886.
93. Reeder JD, Schuman GE. Influence of livestock grazing on C sequestration in semi-arid mixed-grass and short-grass rangelands. Environmental Pollution,2002.116:457-463.
94. Rees RM, Bingham IJ, Baddeley JA, Watson CA. The role of plants and land management in sequestering soil carbon in temperate arable and grassland ecosystems. Geoderma,2005.128: 130-154.
95. Ritchie ME, Tilman D, Johannes MHK. Herbivore effects on plant and nitrogen dynamics in oak savanna. Ecology,1998.79:165-177.
96. Rossignol N, Bonis A, Bouzille JB. Consequence of grazing pattern and vegetation structure on the spatial variations of net N mineralization in a wet grassland. Applied Soil Ecology, 2006.31:62-70.
97. Saviozzi A, Levi-Minzi R, Cardelli R, Riffaldi R. A comparision of soil quality in adjacent cultivated, forest and native grassland soils. Plant & Soil,2001.233:251-259.
98. Shrestha G, Stahl PD. Carbon accumulation and storage in semi-arid sagebrush steppe: Effects of long-term grazing exclusion. Agriculture Ecosystems & Environment,2008.125: 173-181.
99. Singh JS, Raghubanshi AS, Singh RS, Srivastava SC. Microbial biomass act as a source of plant nutrients in dry tropical forest and savanna. Nature,1989.338:499-500.
100. Six J, Callewaert P, Lenders S, De Gryze S, Morris SJ, Gregorich EG, Paul EA, Paustian K. Measuring and understanding carbon storage in afforested soils by physical fractionation. Division S-7 Forest and Range Soils. Soil Science Society of America Journal,2002.66: 1981-1987.
101. Smith OH, Petersen GW, Needelman BA. Environmental indicators of agroecosystems. Advances in Agronomy,2000.69:75-97.
102 Sparling GP. Ratio of microbial biomass carbon to soil organic carbon as a sensitive indicator of changes in soil organic matter. Australian Journal of Soil Research,1992.30:195-207.
103. Srivastava SC, Singh JS. Microbial C, N and P in dry tropical forest soils:effect of alternate land-uses and nutrient flux. Soil Biology & Biochemistry,1991.23:117-124.
104. Steffens M, Kolbl A, Totsche KU, Kogel-Knabner I. Grazing effects on soil chemical and physical properties in a semiarid steppe of Inner Mongolia (P.R. China). Geoderma,2008. 143:63-72.
105. Stockdale E A, Brookes PC. Detection and quantification of the soil microbial biomass-impacts on the management of agricultural soils. Journal of Agricultural Science, 2006.144:285-302.
106. Su YZ, L YL, Cui JY, Zhao WZ. Influences of continuous grazing and livestock exclusion on soil properties in a degraded sandy grassland, Inner Mongolia, northern China. Catena,2005. 59:267-278.
107. Su YZ, Zhao HL, Zhang TH, Zhao XY. Soil properties following cultivation and non-grazing of a semiarid sandy grassland in northern China. Soil & Tillage Research,2004.75:27-36.
108. Sun G, Luo P, Wu N, Qiu PF, Gao YH, Chen H, Shi FS. Stellera chamaejasme L. increases soil N availability, turnover rates and microbial biomass in an alpine meadow ecosystem on the eastern Tibetan Plateau of China. Soil Biology & Biochemistry,2009.41:86-91.
109. Sutie JM, Reynolds SG, Batello C (eds.), Grasslands of the World. Plant production & Protection Series,34. FAO, Rome.2005.
110. Tate III, RL. The carbon cycle. In:Tate Ⅲ, RL. (ed.) Soil microbiology. John Wiley and Sons, New York.2000.
111. Templer PH, Groffman PM, Flecker AS, Power AG Land use change and soil nutrient transformations in the Los Haitises region of the Dominican Republic. Soil Biology & Biochemistry,2005.37:215-225.
112 Thomas GA, Dalal RC, Standley J. No-till effects on organic matter, pH, cation exchange capacity and nutrient distribution in a Luvisol in the semi-arid subtropics. Soil & Tillage Research,2007.94:295-304.
113. Tonon G, Boldreghini P, Gioacchini P. Seasonal changes in microbial nitrogen in an old broadleaf forest and in a neighboring young plantation. Biology & Fertility of Soils,2005.41: 101-108.
114. Tripathi N, Singh RS. Influence of different land uses on soil nitrogen transformations after conversion from an Indian dry tropical forest. Catena,2009.77:216-223.
115. Trumbore SE, Chadwick OA, Amundson R. Rapid exchange between soil carbon and atmospheric carbon dioxide driven by temperature change. Science,1996.272:393-396.
116. Voroney RP, Van Veen JA, Paul EA. Organic C dynamics in grassland soils:2. Model validation and simulation of the long-term effects of cultivation and rainfall erosion. Canadian Journal of Soil Science,1981.61:211-224.
117. Wallander H, Nilsson LO, Hagerberg D, et al. Direct estimates of C:N ratios of ectomycorrhizal mycelia collected from Norway spruce forest soils. Soil Biology & Biochemistry,2003.35:997-999.
118. Wang CH, Wan SQ, Xing XR, Zhang L, Han XG Temperature and soil moisture interactively affected soil net N mineralization in temperate grassland in Northern China. Soil Biology & Biochemistry,2006.38:1101-1110.
119. Wang HK, McSorley R, Bohlen P, Gathumni SM. Cattle grazing increases microbial biomass and alters soil nematode communities in subtropical pastures. Soil Biology & Biochemistry, 2006.38:1956-1965.
120. Wang HQ, Cornell JD, Hall CAS, Marley DP. Spatial and seasonal dynamics of surface soil carbon in the Luquillo Experimental Forest, Puerto Rico. Ecological Modelling,2002.147: 105-122.
121. Wang XL, Jia Y, Li XG, Long RJ, Ma QF, Li FM, Song YJ. Effects of land use on soil total and light fraction organic, and microbial biomass C and N in a semi-arid ecosystem of northwest China. Geoderm,2009.153:285-290.
122 Wang ZP, Han XG, Li LH. Effects of grassland conversion to croplands on soil organic carbon in the temperate Inner Mongolia. Journal of Environmental Management,2008.86: 529-534.
123. Warren SD, Nevill MB, Blackburn WH, et al. Soil response to trampling under intensive rotation grazing. Soil Science Society of America Journal,1986.50:1336-1340.
124. Wardle DA. A comparative assessment of factors which influence microbial biomass carbon and nitrogen levels in soil. Biological Reviews,1992.67:321-358.
125. Wardle DA, Ghani RL. A critique of the microbial metabolic quotient (qCO2) as a bioindicator of disturbance and ecosystem development. Soil Biology & Biochemistry,1995. 27:1601-1610.
126. Wick B, Kuhne RF, Velk PLG Soil microbiological parameters as indicators of soil quality under improved fallow management systems in south-western Nigeria. Plant & Soil,1998. 202:97-107.
127. Wick B, Kiihne RF, Viehauer KK, Vlek PLG. Temporal variability of selected soil microbiological and biochemical indicators under different soil quality conditions in south-western Nigeria. Biology & Fertility of Soils,2002.35:155-167.
128. Wilson JR. Advances in Nitrogen Cycling in Agriculture Ecosystem. Wallingford:C. A. B. International,1988. pp.368-386.
129. Wu R, Tiessen H. Effect of land use on soil degradation in Alpine grassland soil, China. Soil Science Society of American Journal,2002.66:1648-1655
130. XieYZ, Wittig R. The impact of grazing intensity on soil characteristics of Stipa grandis and Stipa Bungeana steppe in northern China (autonomous region of Ningxia). Acta Oecologica, 2004.25:197-204.
131. Yan H, Wang SQ, Wang CK, Zhang GP, Patel N. Losses of soil organic carbon under wind erosion in China. Global Change Biology,2005.11:828-840.
132 Yan TM, Yang LZ, Campbell CD. Microbial biomass and metabolic quotient of soils under different land use in the Three Gorges Reservoir area. Geoderma,2003.115:129-138.
133. Yimer F, Ledin S, Abdelkadir A. Changes in soil organic carbon and total nitrogen contents in three adjacent land use types in the Bale Mountains, south-eastern highlands of Ethiopia. Forest Ecology & Management,2007.242:337-342.
134. Zhang XL, Wang QB, Li LH, Han XG Seasonal variations in nitrogen mineralization under three land use types in a grassland landscape. Acta Oecologica,2008.34:322-330.
135. Zhao X, Wang Q, Kakubari Yoshitaka. Stand-scale spatial patterns of soil microbial biomass in natural cold-temperate beech forests along an elevation gradient. Soil Biology & Biochemistry,2009.41:1466-1474.
136. Zhao WZ, Xiao HL, Liu ZM, Li J. Soil degradation and restoration as affected by land use change in the semiarid Bashang area, northern China. Catena,2005.59:173-186.
137. Zou XM, Ruan HH, Fu Y, et al. Estimating soil labile organic carbon and potential turnover rates using a sequential fumigation-incubation procedure. Soil Biology and Biochemistry, 2005.37:1923-1928
138.陈声明.土壤生物.In：黄昌勇(主编),土壤学.北京：中国农业出版社,2000.pp.50-57.
139.戴全厚,薛走,刘国彬,等.黄土丘陵区封禁对侵蚀土壤微生物生物量的影响.土壤学,2008.45(3)：518-525.
140.傅华,裴世芳,张洪荣.贺兰山西坡不同海拔梯度草地土壤氮特征.草业学报,2005.14(6)：50-56.
141.干友民,李志丹,王钦,等.川西北亚高山草甸放牧退化演替研究.草地学报,2005.13：48-52.
142.高英志,韩兴国,汪诗平.放牧对草原土壤的影响,生态学报,2004.24(4)：790-797.
143.黄昌勇.土壤酸碱性和氧化还原反应.In：黄昌勇(主编),土壤学.北京：中国农业出版社,2000.pp.171-179.
144.李凌浩,刘先华,陈佐忠.内蒙古锡林河流域羊草草原生态系统碳素循环研究.植物学报,1998.40(10)：955-961.
145.李世清,任书杰,李生秀.土壤微生物体氮的季节性变化及其与土壤水分和温度的关系. 植物营养与肥料学报,2004.10(1)：18-23.
146.李香真,陈佐忠.不同放牧率对草原植物与土壤C,N,P含量的影响.草地学报,1998.6(2)：90-98.
147.李香真,曲秋皓.蒙古高原草原土壤微生物量碳氮特征.土壤学报,2002.39(1)：97-104.
148.李永宏,汪诗平.植物种群对牲畜放牧的无性繁殖策略.In：内蒙古草地生态系统研究站(主编),草原生态系统研究.北京：科学出版社,1997.pp.23-31.
149.龙健,黄昌勇,滕应,等.矿区重金属污染对土壤环境质量微生物学指标的影响.农业环境科学学报,2003.22(1)：60-63.
150.鲁如坤.土壤农业化学分析方法.北京：农业科技出版社,2000.pp.228-233.
151.牛叔文,马利邦,曾明明.过牧对玛曲草地沙化的影响.生态学报,2008.28(1)：145-153.
152.潘根兴.土壤退化与土壤质量.In：黄昌勇(主编),土壤学.北京：中国农业出版社,2000.
153.邱建军,秦小光.农业生态系统碳氮循环模拟模型研究.世界农业,2002.9：39-41.
154.戎郁萍,韩建国,等.放牧强度对草地土壤理化性质的影响.中国草地,2001.23(4)：41-47.
155.施政,汪家社,何容,等.武夷山不同海拔土壤呼吸及其主要调控因子.生态学杂志,2008.27(4)：563-568.
156.苏永中,赵哈林,张铜会,等.不同退化沙地土壤碳的矿化潜力.生态学报,2004.24(2)：372-377.
157.孙波,赵其国,张桃林,等.土壤质量与持续环境.Ⅲ：土壤质量评价的生物学指标.土壤,1997.29(5)：225-234.
158.唐玉姝,魏朝富,颜廷梅,等.土壤质量生物学指标研究进展.土壤,2007.39(2)：157-163.
159.田种存,高旭升,陈玉福,等.不同海拔高度下高山草原土土壤养分变化初探.青海农林科技,2006.3：66-70.
160.王常慧,邢雪荣,韩兴国.草地生态系统中土壤氮素矿化影响因素的研究进展.应用生态学报,2004.15：2148-2188.
161.王长庭,龙瑞军,曹广民,等.三江源地区主要草地类型土壤碳氮沿海拔变化特征及其影响因素.植物生态学报,2006.30(3)：441-449.
162.王长庭,龙瑞军,王启基,等.高寒草甸不同海拔梯度土壤有机质氮磷的分布和生产力变化及其与环境因子的关系.草业学报,2005.14(4)：15-20.
163.王建安,韩国栋,鲍雅静,等.我国草地生态系统碳氮循环研究概述.内蒙古农业大学学报,2007.28(4)：254-258.
164.王其兵,李林浩,白永飞,等.气候变化对草甸草原土壤氮素矿化作用影响的实验研究.植物生态学,2000.24(6)：687-692.
165.王启兰,王长庭,杜岩功,等.放牧对高寒嵩草草甸土壤微生物量碳的影响及其与土壤环境的关系.草业学,2008.17(2)：39-46.
166.王文颖,王启基,王刚,等.高寒草甸土地退化及其恢复重建对植被碳、氮含量的影响.植物生态学报,2007.31(6)：1073-1078.
167.王艳芬,陈佐忠,Tieszen LT.人类活动对锡林郭勒地区主要草原土壤有机碳分布的影响.植物生态学报,1998.22(6)：545-551.
168.王一博,王根绪,张春敏,等.高寒植被生态系统变化对土壤物理化学性状的影响.冰川冻土,2007.29(6)：921-927.
169.吴建国,艾丽.祁连山3种典型生态系统土壤微生物活性和生物量碳氮含量.植物生态学报,2008.32(2)：465-476.
170.吴建国,韩梅,苌伟,等.祁连山中部高寒草甸土壤氮矿化及其影响因素研究.草业学报,2007.16(6)：39-46.
171.吴田乡,黄建辉.放牧对内蒙古典型草原生态系统植物及土壤δ15N的影响.植物生态学报,2010.34(2)：160-169.
172.徐华勤,章家恩,冯丽芳,等.广东省不同土地利用方式对土壤微生物量碳氮的影响.生态学报,2009.29(8)：4112-4118.
173.徐建明.土壤有机质.In：黄昌勇(主编),土壤学.北京：中国农业出版社.2000.
174.徐秋芳,姜培坤,沈泉.灌木林与阔叶林土壤有机碳库的比较研究.北京林业大学学报,2005.27(2)：18-22.
175.薛晓娟,李英年,杜明远,等.祁连山东段南麓不同海拔土壤有机质及全氮的分布状况.冰川冻土,2009.31(4)：642-649.
176.杨成德,龙瑞军,陈秀蓉,等.东祁连山高寒草甸土壤微生物量及其与土壤物理因子相关性特征.草业学报,2007.16(4)：62-68.
177.宇万太,姜子绍,周桦,等.不同土地利用方式对潮棕壤微生物量碳及其周转率的影响.生态学杂志,2008.27(8)：1302-1306.
178.赵吉.不同放牧率对冷蒿小禾草草原土壤微生物数量和生物量的影响.草地学报,1999.7(3)：223-227.
179.赵吉,廖仰南,张桂枝,等.草原生态系统的土壤微生物生态.中国草地,1999.3：57-67.
180.赵其国,周生路.土壤退化及其恢复重建.In：赵其国等(主编),土壤资源概论.北京：科学出版社.2007.
181.郑杰炳,王子芳,周春蓉,等.土地利用方式对紫色土丘陵区土壤剖面碳、氮影响.生态环境,2008.17(5)：2041-2045.
182.周华坤,周立,赵新全,等.放牧干扰对高寒草场的影响.中国草地,2002.24(5)：53-61.
183.周兴民.人类活动对高寒草地生态系统多样性的影响.In：陈灵芝,王祖望(主编),人类活动对生态系统多样性的影响.浙江：科学技术出版社.1999.
184.周焱,徐宪根,王丰,等.武夷山不同海拔梯度土壤微生物生物量、微生物呼吸及其商值(qMB,qCO2).生态学杂志,2009.28(2)：265-269.
185.张蕴薇,韩建国,韩永伟,等.不同放牧强度下人工草地土壤微生物量碳、氮的含量.草地学报,2003.11(4)：342-345.
186.中国土壤学会农业化学专业委员会.土壤农业化学常规分析方法.北京：科学出版社,1983.pp.20-169.
2 Almeida FL, Cassia de PM, Josefine FB, Clemente CC, Pellegrino CCE. Inorganic nitrogen, microbial biomass and microbial activity of a sandy Brazilian Cerrado soil under different land uses. Agriculture, Ecosystems & Environment,2010.135 (3):161-167.
3. Alvarez R, Alvarez CR. Soil organic matter pools and their associations with C mineralization kinetics. Soil Science Society of America Journal.2000.64:184-189.
4. Ananyeva ND, Demkina TS, Jones WJ, Cabrera ML, Steen WC. Microbial biomass in soils of Russia under long-term management practices. Biology & Fertility of Soils,1999.29: 291-299.
5. Anderson TH, Domsch KH. Carbon link between microbial biomass and soil organic matter. In:Megusar F.& Gantar M. (eds.) Proceedings of the Fourth International Symposium, Microbial Ecology Soc Microbial Lujbljana,1986. pp.467-471.
6. Anderson TH, Domsch KH. Application of eco-physiological quotients (qCO2 and qD) on microbial biomasses from soils of different cropping histories. Soil Biology & Biochemistry, 1990.22:251-255.
7. Anderson TH, Domsch KH. The matobolic quotient for CO2 (qCO2) as a specific activity parameter to assess the microbial biomass of forest soils. Soil Biology & Biochemistry, 1993a.25:393-395.
8. Anderson TH, Domsch KH. The metabolic quotient for CO2 (qCO2) as a specific activity parameter to assess the effects of environmental conditions, such as pH, on the microbial biomass of forest soils. Soil Biology & Biochemistry,1993b.22:251-255.
9. Arvidsson J. Influence of soil texture and organic matter content on bulk density, air content, compression index and crop yield and laboratory compression experiments. Soil & Tillage Research,1998.4:159-170.
10. Bardgett RD, Leemans DK. The short-term effects of cessation of fertilizer applications, liming and grazing on microbial biomass and activity in a reseeded upland grassland soil.
Biology & Fertility of Soils,1995.19:148-154.
11. Bardgett RD, Leemans DK, Cook R, Hobbs P J. Seasonality in the soil biota of grazed and ungrazed hill grasslands. Soil Biology & Biochemistry,1997.2:1285-1294.
12 Bardgett RD, Wardle DA, Yeates GW. Linking above-ground and below-ground interactions: how plant responses to foliar herbivory influence soil organisms. Soil Biology & Biochemistry 1998.30:1867-1878.
13. Baron VS, Mapfumo E, Dick AC, Naeth MA, Okine EK, Chanasyk DS. Grazing intensity impacts on pasture carbon and nitrogen flow. Journal of Range Management,2002.55: 535-541.
14. Bauer A, Cole CV, Black AL. Soil property comparisons in virgin grasslands between grazed and no-grazed management systems. Soil Science Society of American Journal,1987.51: 176-182.
15. Brookes PC. The use of microbial parameters in monitoring soil pollution by heavy metals. Biology & Fertility of Soils,1995.19:269-279.
16. Carter MR. Microbial biomass and mineralizable N in Solonetzic soils:Influence of gypsum and time amendments. Soil Biology & Biochemistry,1986.18:531-537.
17. Carter MR. Soil quality for sustainable management:organic matter and aggregation indicators that maintain soil functions. Agronomy Journal,2002.94:38-47.
18. Castillo VM, Mena MM, Albaladejo J. Runoff and soil loss response to vegetation removal in a semiarid environment. Soil Science Society of America Journal,1997.61:1071-1076.
19. Celik I. Land-use effects on organic matter and physical properties of soil in a southern Mediterranean highland of Turkey. Soil & Tillage Research,2005.83:270-277.
20. Charles T, Garten J, Paul JH. Measured forest soil C stocks and estimated turnover times along an elevation gradient. Geoderma,2006.136:342-352.
21. Chen Y, Tang H. Desertification in north China:background, anthropogenic impacts and failures in combating it. Land Degradation & Development,2005.16:367-376.
22. Coffin DP, Laycock WA, Lauenroth WK. Disturbance intensity and above-and below-ground herbivory effects on long-tern (14 years) recovery of a semi-arid grassland. Plant Ecology,1998.139:221-233.
23. Cui XY, Wang YF, Niu HS, Wu J, Wang SP, Schnug E, Rogasik J, Fleckenstein J, Tang YH. Effect of long-term grazing on soil organic carbon content in semiarid steppes in Inner Mongolia. Ecological Research,2005.20:519-527.
24. Dakhah M, Gifford GF. Influence of vegetation, rock cover and tramp ling on infiltration rates and sediment production. Water Resource Bulletin,1980.16:979-986.
25. Davidson EA, Matson PA, Vitousek PM, Riley R, Dunkin K, Garciamendez G, Maass JM. Processes regulating soil emissions of NO and N2O in a seasonally dry tropical forest. Ecology,1993.74:130-139.
26. Deenik J. Nitrogen mineralization potential in important agricultural soils of Hawai'i. Soil Crop Management,2006.15:1-5.
27. Dendooven L, Merckx R, Vlassak K. Limitations of a calculated N mineralization potential in studies of the N mineralization process. Plant & Soil,1995.177:175-181.
28. Derner JD, Beriske DD, Boutton TW. Does grazing mediate soil carbon and nitrogen accumulation beneath C4, perennial grasses along an environmental gradient? Plant & Soil, 1997.191:147-156.
29. Derner JD, Boutton TW, Briske DD. Grazing and ecosystem carbon storage in the North American Great Plains. Plant & Soil,2006.280:77-90.
30. Devi BV, Yadava PS. Seasonal dynamics in soil microbial biomass C, N and P in a mixed-oak forest ecosystem of Manipur, Northeast India. Applied Soil Ecology,2006.31:220-227.
31. Diaz-Ravina M, Acea MJ, Carballas T. Seasonal changes in microbial biomass and nutrient flush in forest soils. Biology & Fertility of Soils,1995.19:220-226.
32 Dilly O, Blume HP, Sehy U, Jimenez M, Munch JC. Variation of stabilized, microbial and biologically active carbon and nitrogen in soil under contrasting land use and agricultural management practices. Chemosphere,2003.52:557-569.
33. Dilly O, Munch JC. Ratios between estimates of microbial biomass content and microbial activity in soils. Biology & Fertility of Soils,1998.27:374-379.
34. Dube F, Zagal E, Stolpe N, Espinosa M. The influence of land-use change on the organic carbon distribution and microbial respiration in a volcanic soil of the Chilean Patagonia. Forest Ecology & Management,2009.257:1695-1704.
35. Frank AB, Liebig MA, Tanaka DL. Management effects on soil CO2 efflux in northern semiarid grassland and cropland. Soil&Tillage Research,2006.89:78-85.
36. Frank AB, Tanaka DL, Hofinann L, et al. Soil carbon and nitrogen of Northern Great Plains grasslands as influenced by long-term grazing. Journal of Range Management,1995.48 (5): 470-474.
37. Fu BJ, Liu SL, Lu YH, Chen LD, Ma KM, Liu LH. Comparing the soil quality changes of different land uses determined by two quantitative methods. Journal of Environmental Sciences,2003.15:167-172
38. Gao YH, Luo P, Wu N, Chen H, Wang GX. Grazing intensity impacts on carbon sequestration in an Alpine Meadow on the eastern Tibetan Plateau. Research Journal of Agriculture & Biological Science,2007.3 (6):642-647.
39. Garcia PJ, Casals P, Camarero L, et al. Factors regulating carbon mineralization in the surface and subsurface soils of Pyrenean mountain grasslands. Soil Biology & Biochemistry,2008. 40:2803-2810.
40. Garten CT, Hanson PJ. Measured forest soil C stocks and estimated turnover times along an elevation gradient. Geoderma,2006.136:342-352.
41. Garten CT, Post WM, Hanson PJ, Cooper LW. Forest soil carbon inventories and dynamics along an elevation gradient in the southern Appalachian Mountains. Biogeochemistry,1999. 45:115-145.
42 Grayston SJ, Vaughan D, Jones D. Rhizosphere carbon flow in trees, incomparison with annual plants:the importance of root exudation and its impact on microbial activity and nutrient availability. Applied Soil Ecology,1996.5:29-56.
43. Greenwood KL, MacLeod DA, Hutchinson KJ. Long-term stocking rate effects on soil physical properties. Australian Journal of Experimental Agriculture,1997.37:413-419.
44. Han GD, Hao XY, Zhao ML, Wang MJ, Ellert BH, Water Willms, Wang MJ. Effect of grazing intensity on carbon and nitrogen in soil and vegetation in a meadow steppe in Inner Mongolia. Agriculture Ecosystem & Environment,2008.125:21-32.
45. Hao L, Lal R, Owens LB, Izaurralde RC, Post WM, Hothem DL. Effect of cropland management and slope position on soil organic carbon pool at the North Appalachian Experimental Watersheds. Soil & Tillage Research,2002.68:133-142.
46. Harris D, Voroney RP, Paul EA. Measurement of microbial biomass N:C by chloroform fumigation-incubation. Canadian Journal of Soil Science,1997.77:507-514.
47. Hart SC, Perry DA. Transferring soils from high-to low-elevation forests increases nitrogen cycling rates:climate change implications. Global Change Biology,1999.5:23-32.
48. He ZL, Wu J, O'Donnell AG, Syers JK. Seasonal responses in microbial biomass carbon, phosphorus and sulphur in soils under pasture. Biology & Fertility of Soils,1997.24: 421-428.
49. Hofstede RGM. The effects of grazing and burning on soil and plant nutrient concentrations in Colombia Paramo grasslands. Plant & Soil,1995.173:111-132.
50. Holt JA. Grazing pressure and soil carbon, microbial biomass and enzyme activities in semi-arid northeastern Australia. Applied Soil Ecology,1997.5:143-149.
51. Ineson P, Taylor K, Harrison AF, et al. Effects of climate change on nitrogen dynamics in upland soil.1. A transplant approach. Global Change Biology,1998.4:143-152.
52 Insam H. Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil Biology & Biochemistry,1990.22:525-532.
53. Insam H, Domsch KH. Relationship between soil organic carbon and microbial biomass on chronosequences of the reclamation sites. Microbial Ecology,1988.15:177-188.
54. Islam KR, Weil RR. Land-use effects on soil quality in a tropical forest ecosystem of Bangladesh. Agriculture, Ecosystems & Environment,2000.79:9-16.
55. Jenkinson DS. The determination of microbial biomass carbon and nitrogen in soils. In Wilson JR. (ed.), Advances in Nitrogen Cycling in Agricultural Ecosystems. CAB International, Wallingford; New York,1988. pp.368-386.
56. Jia GM, Cao J, Wang G. Influence of land management on soil nutrients and microbial biomass in the central Loess Plateau, northwest China. Land Degradation & Development, 2005a.16:455-462.
57. Jia GM, Cao J, Wang CY, Wang G. Microbial biomass and nutrients in soil at the different stages of secondary forest succession in Ziwulin, northwest China. Forest Ecology& Management,2005b.217:117-125.
58. Jia S, Li S, Chen Y, Dong H, Guo B. Soil physical properties and water regime in process of grassland degradation and restoration. In:Inner Mongolia Grassland Ecosystem Research Station (ed.), Research on Grassland Ecosystem. Science, Beijing,1997. pp.111-117.
59. Joergensen RG,Scheu S. Depth gradients of microbial and chemical properties in moder soils
under beech and spruce. Pedobiology,1999.43:134-144.
60. Kemmitt SJ, Wright D, Goulding KWT, et al. pH regulation of carbon and nitrogen dynamics in two agricultural soils. Soil Biology & Biochemistry,2006.38:898-911.
61. Killham K. Soil Ecology. Cambridge University Press, Cambridge.1994.
62 Li XG, Li FM, Rengel Z, Zhan ZY, Singh B. Soil physical properties and their relations to organic carbon pools as affected by land use in an alpine pastureland. Geoderma,2007a.139: 98-105.
63. Li XG, Rengel Z, Mapfumo E, Singh B. Increase in pH stimulates mineralization of'native' organic carbon and nitrogen in naturally salt-affected sandy soils. Plant & soil,2007b.290: 269-282.
64. Li Y, Ruan H, Zou X, et al. Response of major soil decomposers to landslide disturbance in a Puerto Rican rainforest. Soil Science,2005.170:202-211.
65. Maithani K, Arunachalam A, Tripathi RS, et al. Nitrogen mineralization as influenced by climate, soil and vegetation in subtropical humid forest in northeast India. Forest Ecology& Management,1998.109:91-101.
66. Malchair S, Carnol M. Microbial biomass and C and N transformations in forest floors under European beech, sessile oak, Norway spruce and Douglas-fir at four temperate forest sites. Soil Biology & Biochemistry,2009.41:831-839.
67. Ma MJ, Zhou XH, Du GZ. Role of soil seed bank along a disturbance gradient in an alpine meadow on the Tibet plateau. Flora,2010.205:128-134.
68. Mazzarino MJ, Bertiller MB, Sain C, et al. Soil nitrogen dynamics in northeastern Patagonia steppe under different precipitation regimes. Plant & Soil,1998.202:125-131.
69. Mazzarino MJ, Szott L, Jimenez M. Dynamics of soil total carbon, nitrogen, microbial biomass and water soluble carbon in tropical agroecosystems. Soil Biology & Biochemistry, 1993.25:205-214.
70. McInnes PF. Effects of moose brow sing on vegetation and litter of the boreal forest. Ecology, 1992.73:2059-2075.
71. McNaughton SJ. Ecology of a grazing ecosystem:the Serengeti. Ecological Monographs, 1985.53:291-320.
72 McNaughton SJ, Ruess RW, Seagle SW. Large mammals and process dynamics in African ecosystems. BioScience,1988.38:794-800.
73. Milchunas DG, Laurenroth WK. Quantitative effects of grazing on vegetation and soils over a global range of environments. Ecological Monographs,1993.63:327-366.
74. Milchunas DG, Laurenroth WK, Burke LC. Livestock grazing:animal and plant biodiversity of short-grass steppe and the relationship to ecosystem functioning. Oikos,1998.83:65-74.
75. Miralles I, Ortega R, Almendros G, Sanchez-Maranon M, Soriao M. Soil quality and organic carbon ratios in mountain agroecosystems of South-east Spain. Geoderma,2009.150: 120-128.
76. Morecroft MD, Marrs RH, Woodward FI. Altitudinal and seasonal trends in soil nitrogen mineralization rate in the Scottish Highlands. Journal of Ecology,1992.80:49-56.
77. Moscatelli MC, Di Tizio A, Marinari S, Grego S. Microbial indicators related to soil carbon in Mediterranean land use systems. Soil Tillage & Research,2007.97:51-59.
78. Mwendera EJ, Mohamed SMA. Infiltration rates, surface runoff, and soil loss as influenced by grazing pressure in Ethiopian highlands. Soil Use & Management,1997.13:29-35.
79. Naeth MA, Bailey AW, Pluth DJ, et al. Grazing impacts on litter and soil organic matter in mixed prairie and fescue grassland ecosystem s of Alberta. Journal of Range Management, 1991.44:7-12.
80. Nannipieri P, Grego S, Ceccanti B. Ecological significance of the biological activity in soil. In:Bollag JM, Stotzky G. (eds.), Soil viochemistry, vol.6. Marcel Dekker, New York, NY, U.S.A.,1990. pp.293-355.
81. Nsabimana D, Haynes RJ, Wallis FM. Size, activity and catabolic diversity of the soil microbial biomass as affected by land use. Applied Soil Ecology,2004.26:81-92.
82 Ocio JA, Brookes PC. An evaluation of methods for measuring microbial biomass in soils following recent additions of wheat straw and the characterization of the biomass that develops. Soil Biology & Biochemistry,1990.22:685-694.
83. Odum E. Trends expected in stressed ecosystems. Bioscience,1985.35:419-422.
84. Ohtsuka T, Hirota M, Zhang XZ, Shimono A, Senga Y, Du MG, Yonemura S, Kawashima S, Tang YH. Soil organic carbon pools in alpine to nival zones along an altitudinal gradient (4400-5300 m) on the Tibetan Plateau. Polar Science,2008.2:277-285.
85. Oldeman LR, Hakkeling RTA, Som broek WG. World map of the status of human-incuded
soil degradation:An explanatory note. In:Wageningen. The Netherlands and Nairobi, Kenya: International Soil Reference and information Center and United Nations Environment Programmer.1991.
86. Paustian K, Six J, Elliott ET, Hunt HW. Management options for reducing CO2 emissions from agricultural soils. Biogeochemistry,2000.48:147-163.
87. Percival HJ, Parfitt RL, Scott NA. Factors controlling soil carbon levels in New Zealand grassland:Is clay content important? Soil Science Society of America Journal,2000.64: 1623-1630.
88. Piao HC, Hong YT, Yuan ZY. Seasonal changes of microbial biomass carbon related to climatic factors in soils from karst areas of southwest China. Biology& Fertility of Soils, 2000.30:294-297.
89. Post WM, Emanuel R, Zinke PJ, et al. Soil carbon pools and world life zones. Nature,1982. 298:156-159.
90. Powlson DS, Brookes PC, Christensen BT. Measurement of soil microbial biomass provides an early indication of changes in total soil organic matter due to straw incorporation. Soil Biology & Biochemistry,1987.19:159-164.
91. Powlson DS, Jenkinson DS. A comparison of the organic matter, biomass, adenosine triphosphate and mineralizable nitrogen contents of ploughed and direct-drilled soils. Journal of Agricultural Science,1981.97:713-721.
92 Prescott CE, Chappell NH, Vesterda L. Nitrogen turnover in forest floors of coastal Douglas fir at sites differing in soil nitrogen capital. Ecology,2000.81:1878-1886.
93. Reeder JD, Schuman GE. Influence of livestock grazing on C sequestration in semi-arid mixed-grass and short-grass rangelands. Environmental Pollution,2002.116:457-463.
94. Rees RM, Bingham IJ, Baddeley JA, Watson CA. The role of plants and land management in sequestering soil carbon in temperate arable and grassland ecosystems. Geoderma,2005.128: 130-154.
95. Ritchie ME, Tilman D, Johannes MHK. Herbivore effects on plant and nitrogen dynamics in oak savanna. Ecology,1998.79:165-177.
96. Rossignol N, Bonis A, Bouzille JB. Consequence of grazing pattern and vegetation structure on the spatial variations of net N mineralization in a wet grassland. Applied Soil Ecology, 2006.31:62-70.
97. Saviozzi A, Levi-Minzi R, Cardelli R, Riffaldi R. A comparision of soil quality in adjacent cultivated, forest and native grassland soils. Plant & Soil,2001.233:251-259.
98. Shrestha G, Stahl PD. Carbon accumulation and storage in semi-arid sagebrush steppe: Effects of long-term grazing exclusion. Agriculture Ecosystems & Environment,2008.125: 173-181.
99. Singh JS, Raghubanshi AS, Singh RS, Srivastava SC. Microbial biomass act as a source of plant nutrients in dry tropical forest and savanna. Nature,1989.338:499-500.
100. Six J, Callewaert P, Lenders S, De Gryze S, Morris SJ, Gregorich EG, Paul EA, Paustian K. Measuring and understanding carbon storage in afforested soils by physical fractionation. Division S-7 Forest and Range Soils. Soil Science Society of America Journal,2002.66: 1981-1987.
101. Smith OH, Petersen GW, Needelman BA. Environmental indicators of agroecosystems. Advances in Agronomy,2000.69:75-97.
102 Sparling GP. Ratio of microbial biomass carbon to soil organic carbon as a sensitive indicator of changes in soil organic matter. Australian Journal of Soil Research,1992.30:195-207.
103. Srivastava SC, Singh JS. Microbial C, N and P in dry tropical forest soils:effect of alternate land-uses and nutrient flux. Soil Biology & Biochemistry,1991.23:117-124.
104. Steffens M, Kolbl A, Totsche KU, Kogel-Knabner I. Grazing effects on soil chemical and physical properties in a semiarid steppe of Inner Mongolia (P.R. China). Geoderma,2008. 143:63-72.
105. Stockdale E A, Brookes PC. Detection and quantification of the soil microbial biomass-impacts on the management of agricultural soils. Journal of Agricultural Science, 2006.144:285-302.
106. Su YZ, L YL, Cui JY, Zhao WZ. Influences of continuous grazing and livestock exclusion on soil properties in a degraded sandy grassland, Inner Mongolia, northern China. Catena,2005. 59:267-278.
107. Su YZ, Zhao HL, Zhang TH, Zhao XY. Soil properties following cultivation and non-grazing of a semiarid sandy grassland in northern China. Soil & Tillage Research,2004.75:27-36.
108. Sun G, Luo P, Wu N, Qiu PF, Gao YH, Chen H, Shi FS. Stellera chamaejasme L. increases soil N availability, turnover rates and microbial biomass in an alpine meadow ecosystem on the eastern Tibetan Plateau of China. Soil Biology & Biochemistry,2009.41:86-91.
109. Sutie JM, Reynolds SG, Batello C (eds.), Grasslands of the World. Plant production & Protection Series,34. FAO, Rome.2005.
110. Tate III, RL. The carbon cycle. In:Tate Ⅲ, RL. (ed.) Soil microbiology. John Wiley and Sons, New York.2000.
111. Templer PH, Groffman PM, Flecker AS, Power AG Land use change and soil nutrient transformations in the Los Haitises region of the Dominican Republic. Soil Biology & Biochemistry,2005.37:215-225.
112 Thomas GA, Dalal RC, Standley J. No-till effects on organic matter, pH, cation exchange capacity and nutrient distribution in a Luvisol in the semi-arid subtropics. Soil & Tillage Research,2007.94:295-304.
113. Tonon G, Boldreghini P, Gioacchini P. Seasonal changes in microbial nitrogen in an old broadleaf forest and in a neighboring young plantation. Biology & Fertility of Soils,2005.41: 101-108.
114. Tripathi N, Singh RS. Influence of different land uses on soil nitrogen transformations after conversion from an Indian dry tropical forest. Catena,2009.77:216-223.
115. Trumbore SE, Chadwick OA, Amundson R. Rapid exchange between soil carbon and atmospheric carbon dioxide driven by temperature change. Science,1996.272:393-396.
116. Voroney RP, Van Veen JA, Paul EA. Organic C dynamics in grassland soils:2. Model validation and simulation of the long-term effects of cultivation and rainfall erosion. Canadian Journal of Soil Science,1981.61:211-224.
117. Wallander H, Nilsson LO, Hagerberg D, et al. Direct estimates of C:N ratios of ectomycorrhizal mycelia collected from Norway spruce forest soils. Soil Biology & Biochemistry,2003.35:997-999.
118. Wang CH, Wan SQ, Xing XR, Zhang L, Han XG Temperature and soil moisture interactively affected soil net N mineralization in temperate grassland in Northern China. Soil Biology & Biochemistry,2006.38:1101-1110.
119. Wang HK, McSorley R, Bohlen P, Gathumni SM. Cattle grazing increases microbial biomass and alters soil nematode communities in subtropical pastures. Soil Biology & Biochemistry, 2006.38:1956-1965.
120. Wang HQ, Cornell JD, Hall CAS, Marley DP. Spatial and seasonal dynamics of surface soil carbon in the Luquillo Experimental Forest, Puerto Rico. Ecological Modelling,2002.147: 105-122.
121. Wang XL, Jia Y, Li XG, Long RJ, Ma QF, Li FM, Song YJ. Effects of land use on soil total and light fraction organic, and microbial biomass C and N in a semi-arid ecosystem of northwest China. Geoderm,2009.153:285-290.
122 Wang ZP, Han XG, Li LH. Effects of grassland conversion to croplands on soil organic carbon in the temperate Inner Mongolia. Journal of Environmental Management,2008.86: 529-534.
123. Warren SD, Nevill MB, Blackburn WH, et al. Soil response to trampling under intensive rotation grazing. Soil Science Society of America Journal,1986.50:1336-1340.
124. Wardle DA. A comparative assessment of factors which influence microbial biomass carbon and nitrogen levels in soil. Biological Reviews,1992.67:321-358.
125. Wardle DA, Ghani RL. A critique of the microbial metabolic quotient (qCO2) as a bioindicator of disturbance and ecosystem development. Soil Biology & Biochemistry,1995. 27:1601-1610.
126. Wick B, Kuhne RF, Velk PLG Soil microbiological parameters as indicators of soil quality under improved fallow management systems in south-western Nigeria. Plant & Soil,1998. 202:97-107.
127. Wick B, Kiihne RF, Viehauer KK, Vlek PLG. Temporal variability of selected soil microbiological and biochemical indicators under different soil quality conditions in south-western Nigeria. Biology & Fertility of Soils,2002.35:155-167.
128. Wilson JR. Advances in Nitrogen Cycling in Agriculture Ecosystem. Wallingford:C. A. B. International,1988. pp.368-386.
129. Wu R, Tiessen H. Effect of land use on soil degradation in Alpine grassland soil, China. Soil Science Society of American Journal,2002.66:1648-1655
130. XieYZ, Wittig R. The impact of grazing intensity on soil characteristics of Stipa grandis and Stipa Bungeana steppe in northern China (autonomous region of Ningxia). Acta Oecologica, 2004.25:197-204.
131. Yan H, Wang SQ, Wang CK, Zhang GP, Patel N. Losses of soil organic carbon under wind erosion in China. Global Change Biology,2005.11:828-840.
132 Yan TM, Yang LZ, Campbell CD. Microbial biomass and metabolic quotient of soils under different land use in the Three Gorges Reservoir area. Geoderma,2003.115:129-138.
133. Yimer F, Ledin S, Abdelkadir A. Changes in soil organic carbon and total nitrogen contents in three adjacent land use types in the Bale Mountains, south-eastern highlands of Ethiopia. Forest Ecology & Management,2007.242:337-342.
134. Zhang XL, Wang QB, Li LH, Han XG Seasonal variations in nitrogen mineralization under three land use types in a grassland landscape. Acta Oecologica,2008.34:322-330.
135. Zhao X, Wang Q, Kakubari Yoshitaka. Stand-scale spatial patterns of soil microbial biomass in natural cold-temperate beech forests along an elevation gradient. Soil Biology & Biochemistry,2009.41:1466-1474.
136. Zhao WZ, Xiao HL, Liu ZM, Li J. Soil degradation and restoration as affected by land use change in the semiarid Bashang area, northern China. Catena,2005.59:173-186.
137. Zou XM, Ruan HH, Fu Y, et al. Estimating soil labile organic carbon and potential turnover rates using a sequential fumigation-incubation procedure. Soil Biology and Biochemistry, 2005.37:1923-1928
138.陈声明.土壤生物.In：黄昌勇(主编),土壤学.北京：中国农业出版社,2000.pp.50-57.
139.戴全厚,薛走,刘国彬,等.黄土丘陵区封禁对侵蚀土壤微生物生物量的影响.土壤学,2008.45(3)：518-525.
140.傅华,裴世芳,张洪荣.贺兰山西坡不同海拔梯度草地土壤氮特征.草业学报,2005.14(6)：50-56.
141.干友民,李志丹,王钦,等.川西北亚高山草甸放牧退化演替研究.草地学报,2005.13：48-52.
142.高英志,韩兴国,汪诗平.放牧对草原土壤的影响,生态学报,2004.24(4)：790-797.
143.黄昌勇.土壤酸碱性和氧化还原反应.In：黄昌勇(主编),土壤学.北京：中国农业出版社,2000.pp.171-179.
144.李凌浩,刘先华,陈佐忠.内蒙古锡林河流域羊草草原生态系统碳素循环研究.植物学报,1998.40(10)：955-961.
145.李世清,任书杰,李生秀.土壤微生物体氮的季节性变化及其与土壤水分和温度的关系. 植物营养与肥料学报,2004.10(1)：18-23.
146.李香真,陈佐忠.不同放牧率对草原植物与土壤C,N,P含量的影响.草地学报,1998.6(2)：90-98.
147.李香真,曲秋皓.蒙古高原草原土壤微生物量碳氮特征.土壤学报,2002.39(1)：97-104.
148.李永宏,汪诗平.植物种群对牲畜放牧的无性繁殖策略.In：内蒙古草地生态系统研究站(主编),草原生态系统研究.北京：科学出版社,1997.pp.23-31.
149.龙健,黄昌勇,滕应,等.矿区重金属污染对土壤环境质量微生物学指标的影响.农业环境科学学报,2003.22(1)：60-63.
150.鲁如坤.土壤农业化学分析方法.北京：农业科技出版社,2000.pp.228-233.
151.牛叔文,马利邦,曾明明.过牧对玛曲草地沙化的影响.生态学报,2008.28(1)：145-153.
152.潘根兴.土壤退化与土壤质量.In：黄昌勇(主编),土壤学.北京：中国农业出版社,2000.
153.邱建军,秦小光.农业生态系统碳氮循环模拟模型研究.世界农业,2002.9：39-41.
154.戎郁萍,韩建国,等.放牧强度对草地土壤理化性质的影响.中国草地,2001.23(4)：41-47.
155.施政,汪家社,何容,等.武夷山不同海拔土壤呼吸及其主要调控因子.生态学杂志,2008.27(4)：563-568.
156.苏永中,赵哈林,张铜会,等.不同退化沙地土壤碳的矿化潜力.生态学报,2004.24(2)：372-377.
157.孙波,赵其国,张桃林,等.土壤质量与持续环境.Ⅲ：土壤质量评价的生物学指标.土壤,1997.29(5)：225-234.
158.唐玉姝,魏朝富,颜廷梅,等.土壤质量生物学指标研究进展.土壤,2007.39(2)：157-163.
159.田种存,高旭升,陈玉福,等.不同海拔高度下高山草原土土壤养分变化初探.青海农林科技,2006.3：66-70.
160.王常慧,邢雪荣,韩兴国.草地生态系统中土壤氮素矿化影响因素的研究进展.应用生态学报,2004.15：2148-2188.
161.王长庭,龙瑞军,曹广民,等.三江源地区主要草地类型土壤碳氮沿海拔变化特征及其影响因素.植物生态学报,2006.30(3)：441-449.
162.王长庭,龙瑞军,王启基,等.高寒草甸不同海拔梯度土壤有机质氮磷的分布和生产力变化及其与环境因子的关系.草业学报,2005.14(4)：15-20.
163.王建安,韩国栋,鲍雅静,等.我国草地生态系统碳氮循环研究概述.内蒙古农业大学学报,2007.28(4)：254-258.
164.王其兵,李林浩,白永飞,等.气候变化对草甸草原土壤氮素矿化作用影响的实验研究.植物生态学,2000.24(6)：687-692.
165.王启兰,王长庭,杜岩功,等.放牧对高寒嵩草草甸土壤微生物量碳的影响及其与土壤环境的关系.草业学,2008.17(2)：39-46.
166.王文颖,王启基,王刚,等.高寒草甸土地退化及其恢复重建对植被碳、氮含量的影响.植物生态学报,2007.31(6)：1073-1078.
167.王艳芬,陈佐忠,Tieszen LT.人类活动对锡林郭勒地区主要草原土壤有机碳分布的影响.植物生态学报,1998.22(6)：545-551.
168.王一博,王根绪,张春敏,等.高寒植被生态系统变化对土壤物理化学性状的影响.冰川冻土,2007.29(6)：921-927.
169.吴建国,艾丽.祁连山3种典型生态系统土壤微生物活性和生物量碳氮含量.植物生态学报,2008.32(2)：465-476.
170.吴建国,韩梅,苌伟,等.祁连山中部高寒草甸土壤氮矿化及其影响因素研究.草业学报,2007.16(6)：39-46.
171.吴田乡,黄建辉.放牧对内蒙古典型草原生态系统植物及土壤δ15N的影响.植物生态学报,2010.34(2)：160-169.
172.徐华勤,章家恩,冯丽芳,等.广东省不同土地利用方式对土壤微生物量碳氮的影响.生态学报,2009.29(8)：4112-4118.
173.徐建明.土壤有机质.In：黄昌勇(主编),土壤学.北京：中国农业出版社.2000.
174.徐秋芳,姜培坤,沈泉.灌木林与阔叶林土壤有机碳库的比较研究.北京林业大学学报,2005.27(2)：18-22.
175.薛晓娟,李英年,杜明远,等.祁连山东段南麓不同海拔土壤有机质及全氮的分布状况.冰川冻土,2009.31(4)：642-649.
176.杨成德,龙瑞军,陈秀蓉,等.东祁连山高寒草甸土壤微生物量及其与土壤物理因子相关性特征.草业学报,2007.16(4)：62-68.
177.宇万太,姜子绍,周桦,等.不同土地利用方式对潮棕壤微生物量碳及其周转率的影响.生态学杂志,2008.27(8)：1302-1306.
178.赵吉.不同放牧率对冷蒿小禾草草原土壤微生物数量和生物量的影响.草地学报,1999.7(3)：223-227.
179.赵吉,廖仰南,张桂枝,等.草原生态系统的土壤微生物生态.中国草地,1999.3：57-67.
180.赵其国,周生路.土壤退化及其恢复重建.In：赵其国等(主编),土壤资源概论.北京：科学出版社.2007.
181.郑杰炳,王子芳,周春蓉,等.土地利用方式对紫色土丘陵区土壤剖面碳、氮影响.生态环境,2008.17(5)：2041-2045.
182.周华坤,周立,赵新全,等.放牧干扰对高寒草场的影响.中国草地,2002.24(5)：53-61.
183.周兴民.人类活动对高寒草地生态系统多样性的影响.In：陈灵芝,王祖望(主编),人类活动对生态系统多样性的影响.浙江：科学技术出版社.1999.
184.周焱,徐宪根,王丰,等.武夷山不同海拔梯度土壤微生物生物量、微生物呼吸及其商值(qMB,qCO2).生态学杂志,2009.28(2)：265-269.
185.张蕴薇,韩建国,韩永伟,等.不同放牧强度下人工草地土壤微生物量碳、氮的含量.草地学报,2003.11(4)：342-345.
186.中国土壤学会农业化学专业委员会.土壤农业化学常规分析方法.北京：科学出版社,1983.pp.20-169.