Revision Date: October 05, 2005

NPP Grassland: Xilingol, China, 1980-1989 Document

Summary:

Productivity of a steppe grassland was determined from 1980 to 1989 at the Inner Mongolia Grassland Research Station of the Chinese Academy of Sciences, within the Xilingol Biosphere Reserve. Measurements of above-ground live biomass, standing dead matter and litter were made bi-weekly from the beginning of May to early October for each year. Above-ground net primary production was estimated by summing peak live biomass of each of 5 species categories.

Steppe grasslands of Leymus chinense and Stipa grandis are the dominant vegetation types, respectively, in the Eastern Eurasian steppe zone (semi-arid and sub-humid) and the middle Eurasian steppe zone (semi-arid). Both species provide good livestock forage and are used mainly as natural grazing lands, and both occur within the Xilingol reserve.

More information on the entire Net Primary Production Project can be found at the NPP homepage.

Table of Contents

  1. Data Set Overview
  2. Investigator(s)
  3. Theory of Measurements
  4. Equipment
  5. Data Acquisition Methods
  6. Observations
  7. Data Description
  8. Data Organization
  9. Data Manipulations
  10. Errors
  11. Notes
  12. Application of the Data Set
  13. Future Modifications and Plans
  14. Software
  15. Data Access
  16. Output Products and Availability
  17. References
  18. Glossary of Terms
  19. List of Acronyms
  20. Document Information

1. Data Set Overview:

Data Set Identification:

NPP Grassland: Xilingol, China, 1980-1989

Introduction:

The 25-hectare Xilingol study site (43.72 N 116.63 E) is located at Baiyinxile Livestock Farm in the Xilin river basin, Inner Mongolia, about 60 km south-east of Xilinhot. It is representative of about 210,000 km2 of "typical steppe" grasslands, out of a total grassland area of about 800,000 km2 in Inner Mongolia. With a warm, wet growing season from the end of April to early October, these typical steppe grasslands provide good quality forage for livestock and are used primarily for grazing. The study site has been fenced since 1980, and was lightly grazed before that time, being distant from settlements and water holes. The study area has been described by Jiang (1985; 1988) and the soils by Wang and Cai (1988). Grassland productivity has been studied by Hayashi et al. (1988) and more recently by Xiao et al. (1995; 1996).

Objective/Purpose:

Long-term dynamics of above-ground biomass and above-ground net primary production were reported by Xiao et al. (1996) with the objectives of: (1) quantifying temporal variability of biomass, primary production, water use efficiency and rain use efficiency of the steppe; and (2) establishing quantitative relationships these parameters and climatic variables.

Summary of Parameters:

Above-ground live biomass

Discussion:

The relatively high above-ground net primary productivity of this steppe grassland (for only modest precipitation) may be attributed partly to (1) optimum monthly and seasonal distribution of precipitation and temperature (Xiao et al., 1995; 1996) and (2) the coarser texture of Inner Mongolian grasslands compared with, for example, the US Great Plains. Comparitively high biological N-fixation could be another factor.

Related Data Sets:

Monthly climate data from 1978 to 1989 (monthly maximum and minimum temperature and monthly rainfall) are available for this study site in the file "xln_cli.txt". NPP data from other grassland sites are available elsewhere in this archive. Summary tables containing site characteristics and metadata for all the grassland sites are also available.

2. Investigator(s):

Investigator(s) Name and Title:

Dr. Xiao Xiangming

Title of Investigation:

Determination of net primary productivity of a steppe grassland at Xilingol, Inner Mongolia.

Contact Information:

Dr. Xiangming Xiao
Complex Systems Research Center
Institute for the Study of Earth, Oceans and Space
University of New Hampshire
Durham, NH 03824
U.S.A.
Telephone: +1 (603) 862-1792/ 862-3818
Fax: +1 (603) 862-0188
Email: xiangming.xiao@unh.edu

Alternative Contact:
Dr. D.S. Ojima
Natural Resource Ecology Laboratory
Colorado State University
Fort Collins
Colorado 80523
U.S.A.
Telephone Number: +1 (970) 491-1976
Fax: +1 (970) 491-1965
Email dennis@nrel.colostate.edu

3. Theory of Measurements:

Net primary production (NPP), sensu stricto, is the total photosynthetic gain (less respiratory losses) of vegetation per unit ground area. For a given period, this is equal to the change in plant mass plus any losses due to death and decomposition, measured for both above ground and below ground plant parts. Earlier estimates of grassland NPP were based on peak standing dry matter only, and the studies of the International Biological Programme (IBP) in the late 1960s and early 1970s were based mainly on above-ground biomass changes, with few estimates of below-ground production.

Peak above-ground live biomass (or in some cases, the difference between maximum and minimum biomass) has been used as an estimate of net primary production - usually where only one or two measurements per year are available. Sometimes a conversion factor has been applied to take account of estimated turnover and the estimated ratio of above-ground to below-ground dry matter.

The "IBP Standard Method" of Milner and Hughes (1968) assumes that where live biomass increases between successive samples, production equals this increase; where biomass decreases or remains the same, production is assumed to be zero. Annual production is then obtained by summing the estimates for each sample interval.

Essentially, this method was used for the IBP synthesis by Singh and Joshi (1979), in particular for their estimates of below-ground production. A modified method was used for above-ground production, determined by a decision matrix (Singh et al., 1975); where increments in live biomass coincided with increases in standing dead matter, the latter were added to the monthly production.

The limitations of the above methods are discussed in detail by Long et al. (1989). In particular, the peak biomass method and variations on the IBP method underestimate production by not accounting for simultaneous growth and death. This may be significant in temperate grasslands with a long growing season, and is particularly a problem in tropical grasslands where the growing season may extend over much of the year. Some limited overestimation may occur by not accounting for periods of negative NPP (due to stress, or translocation between above and below ground plant parts) but underestimation of root turnover is probably the largest source of error. Long et al. (1989) estimated NPP for three terrestrial tropical grassland sites by summing monthly changes in live biomass plus losses due to death and decomposition for above and below ground vegetation. Monthly losses were determined as the change in dead matter plus the estimated disappearance of dead matter through decomposition. Dead matter disappearance was calculated each month as the product of relative decomposition rate and mean amount of dead matter.

Although some correlation between estimates obtained using different methods has been reported (Singh et al., 1975), the degree of underestimation may be strongly site-specific (Linthurst and Reimold, 1978; Long and Mason, 1983). Where sufficient data are available for a given grassland site, it may be possible to estimate NPP according to the different methods for the purposes of comparison. This may involve entry of data into algorithms or a spreadsheet containing these algorithms.

4. Equipment:

Sensor/Instrument Description:

Hand shears

Collection Environment:

Ground level

Platform/Source:

Field investigation, meteorological station

Platform/Source Mission Objectives:

Determination of net primary productivity

Key Variables:

Above-ground live biomass

Principles of Operation:

See "3. Theory" Above

Sensor/Instrument Measurement Geometry:

Not Applicable

Manufacturer of Sensor/Instrument:

Information Not Available

Calibration:

Not Applicable

5. Data Acquisition Methods:

Refer to literature or Principal Investigator/ Contact for details

6. Observations:

Data/Field Notes:

Refer to Principal Investigator (see 2. above) for details of any peculiar conditions at the time of data collection

site elevation (m): 1200

mean annual precipitation (mm): 360

mean monthly min temperature (C): -30.0 (Jan)

mean monthly maximum temperature (C): 25.7 (July)

vegetation type: steppe

dominant species: Leymus chinense (C3 photosynthetic types)

Historical long-term management regime (estimated): light grazing

Maximum aboveground live biomass (typical month): 183 g/m2 (August)

soil type: dark chestnut, coarse texture

soil pH: DATA NOT AVAILABLE

soil texture (sand/silt/clay): 0.60/ 0.19/ 0.21

soil carbon content: 5405 g/m2 (0-20 cm)

soil nitrogen content: 414 g/m2 (0-20 cm)

7. Data Description:

Spatial Characteristics:

Spatial Coverage:

Study site located at 43.72 N 116.63 E

Spatial Coverage Map:

include map of study site location?

Spatial Resolution:

Not Applicable

Projection:

Not Applicable

Grid Description:

Not Applicable

Temporal Characteristics:

Temporal Coverage:

July 1980 to September 1989. Preview data set to check for data gaps, missing values, etc.

Temporal Coverage Map:

Not Applicable

Temporal Resolution:

One month

Data Description:

Parameter/Variable:

Parameter/Variable Description/Definition:

Not Applicable

Units of Measurement:

Data Source:

Not Applicable

Data Range:

Sample Data Record:

1980.583; 70.91

Data Format:

Not Applicable

8. Data Organization:

Data Granularity:

Monthly (field data and weather data). Some daily weather data may be available - refer to Principal Investigator / Contact

A general description of data granularity as it applies to the IMS appears in the EOSDIS Glossary.

9. Data Manipulations:

Formulae:

Derivation Techniques and Algorithms:

It is planned to make algorithms and/or software available for calculating NPP from data sets using different methods.

Data Processing Sequence:

Information Not Available

Calculations

Information Not Available

Graphs and Plots

Information Not Available

10. Errors:

Information Not Available

11. Notes:

Limitations of the Data:

Net primary production of grasslands is subject to a number of different methods of estimation from biomass data, some of which may be inappropriate for particular biome types. Methodology of estimation/calculation needs to be taken into account, as well as methodology of measurement, when making comparisons between different regions. Errors in biomass measurement may also occur between different study sites. For short time series of data it may be assumed that measurement methodology remains consistent; however, over very long time series changes in staff, tools, etc. may lead to "calibration" errors.

Known Problems with the Data:

Information Not Available

Usage Guidance:

See "Limitations of the Data" above

Any Other Relevant Information About the Study:

Information Not Available

12. Application of the Data Set:

Data on net primary production of particular ecosystem types worldwide is in demand from modellers working at a variety of scales from Global Climate Models (GCMs) to regional or national estimates of carbon fluxes between atmosphere, biosphere and soils. Ground-based data are also required for calibration of remote sensing measurements, and parameterisation and validation of models based on remote sensing.

13. Future Modifications and Plans:

Refer to Principal Investigator for details of continuing data collection.

14. Software:

Software Description:

Utility software is planned to available for (i) generating quasi-real daily/hourly climate data from the monthly data; (ii) calculating NPP from data sets using different algorithms, crude root/shoot ratios, etc.

Software Access:

Not Yet Available

15. Data Access:

Contact Information:

ORNL DAAC User Services Office
Oak Ridge National Laboratory
Oak Ridge, TN
U.S.A.

Telephone: +1 (865) 241-3952
Email Address: ornldaac@ornl.gov

Data Center Identification:

ORNL Distributed Active Archive Center
Oak Ridge National Laboratory
Oak Ridge, TN
U.S.A.

Telephone: +1 (865) 241-3952
Email Address: ornldaac@ornl.gov

Procedures for Obtaining Data:

Users may place requests by telephone, electronic mail, or FAX. Data are also available via the World Wide Web at http://daac.ornl.gov.

Data Center Status/Plans:

NPP data are available from the ORNL DAAC. Please contact the ORNL DAAC User Services Office for the most current information about these data.

16. Output Products and Availability:

Available online, as computer FTP file (zipped or unzipped), on tape or IBM-formatted diskettes.

17. References:

Chen Zuozhong, Huang Dehua and Zhang Hongfang (1985) The characteristics of element chemistry of 122 plant species on the Xilin river basin, Inner Mongolia. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 1, 112-131. Science Press, Beijing. (in Chinese with English abstract)

Chen Zuozhong (1988) Topography and climate of Xilin river basin. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 3, 13-22. Science Press, Beijing. (in Chinese with English abstract)

Hayashi, I., S. Jiang, and T. Nakamura (1988) Phytomass production of grasslands in Xilin river basin, Xilingol, Inner Mongolia, China. Bull. Sugadaira Montane Res. Cen. 9, 19-31.

Jiang Shu (1985) An Introduction to the Inner Mongolia Grassland Ecosystem Research Station, Academia Sinica. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 1, 1-13. Science Press, Beijing. (in Chinese with English abstract)

Jiang Shu (1988) The setting-up of the grassland ecosystem research sites and their vegetation status. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 3, 13-22. Science Press, Beijing. (in Chinese with English abstract)

Jiang Shu, Qi Qiuhui and Kong Dezhen (1985) A comparative study on production of Aneurolepidium chinense and Stipa grandis steppe communities at Baiyinxile Livestock Farm in Inner Mongolia Region. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 1, 12-23. Science Press, Beijing. (in Chinese with English abstract)

Li Bo, Yong Shipeng and Liu Zhonghou (1988) The vegetation of the Xilin river basin and its utilization. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 3, 84-183. Science Press, Beijing. (in Chinese with English abstract)

Li Yonghong (1989) Impact of grazing on Aneurolepidium chinense steppe and Stipa grandis steppe. Acta Oecologica/Oecol. Applications 10, 31-46.

Li Yonghong (1992) Accordance of the grassland dynamics on temporal gradient of restoration succession to their changes on spatial gradient of grazing. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 4, 1-7. Science Press, Beijing. (in Chinese with English abstract)

Linthurst, R. and R.J. Reimold (1978) An evaluation of methods for estimating the net primary production of estuarine angiosperms. J. Applied Ecology 15, 919-932.

Liu Shurun and Liu Zongling (1988) Outline of flora of the Xilin river basin, Inner Mongolia. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 3, 227-268. Science Press, Beijing. (in Chinese with English abstract)

Long, S.P. and C.F. Mason (1983) Saltmarsh Ecology. Blackie, Glasgow.

Long, S.P., E. Garcia Moya, S.K. Imbamba, A. Kamnalrut, M.T.F. Piedade, J.M.O. Scurlock, Y.K. Shen and D.O. Hall (1989) Primary productivity of natural grass ecosystems of the tropics: a reappraisal. Plant and Soil 115, 155-166.

Milner, C. and R.E. Hughes (1968) Methods for the Measurement of the Primary Production of Grassland. IBP Handbook No.6. Blackwell, Oxford.

Qi Qiuhui, Jiang Shu and Wang Yifeng (1985) A preliminary study on the relation of structure and biomass of Aneurolepidium chinense grassland community. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 1, 38-47. Science Press, Beijing. (in Chinese with English abstract)

Singh, J.S. and M.C. Joshi (1979) Tropical grasslands primary production. IN: Grassland Ecosystems of the World (R.T. Coupland, ed.) Cambridge University Press. pp. 197-218.

Singh, J.S., W.K. Lauenroth and R.K. Sernhorst (1975) Review and assessment of various techniques for estimating net aerial primary production in grasslands from harvest data. Botanical Review 41, 181-232.

Tieszen, L.L. and Song Bingyu (1990) Stable carbon isotopic variation among plants of the Inner Mongolian grasslands. In: Jiang Shu, Chen Zuozhong and Xiao Xiangming, eds. Reports from the Inner Mongolia Grassland Ecosystem Research Station of Academia Sinica (1979-1988). Science Press, Beijing. pp. 273-287.

Wang Jiuwen and Cai Weichi (1988) Studies on genesis, types and characteristics of the soils of the Xilin river basin. In: Inner Mongolia Grassland Ecosystem Research Station, ed. Research on Grassland Ecosystems 3, 23-83. Science Press, Beijing. (in Chinese with English abstract)

Wang Yifeng, Yong Shipeng and Liu Zhongling (1979) Vegetation characteristics of the Inner Mongolia Autonomous Region. Acta Botanica Sinica 21, 274-283.

Xiao Xiangming, Jiang Shu, Wang Yifeng, D.S. Ojima and C.D. Bonham (1996) Temporal variation in aboveground biomass of Leymus chinense steppe from species to community levels in the Xilin River Basin, Inner Mongolia, China. Vegetatio 123, 1-12.

Xiao Xiangming, Wang Yifeng, Jiang Shu, D.S. Ojima and C.D. Bonham. 1995a. Interannual variation in the climate and aboveground biomass of Leymus chinense steppe and Stipa grandis steppe in the Xilin river basin, Inner Mongolia, China. Journal of Arid Environments 31, 283-299.

18. Glossary of Terms

A general glossary for the DAAC is located at Glossary.

A glossary of EODSIS terms is available at EOSDIS Glossary.

19. List of Acronyms

URL
Uniform Resource Locator

A general list of acronyms for the DAAC is available at Acronyms.

Document Information:

Document Revision Date:

May 25, 1995

Review Date:

September 18, 1996

Document ID:

ORNL-NPP_XLN.

Citation:

Cite this data set as follows:

Xiao, X., and D. Ojima. 1996. NPP Grassland: Xilingol, China, 1980-1989. Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A.

Document Curator:

webmaster@daac.ornl.gov

Document Author:

Dr. J.M.O. Scurlock

Document URL:

http://daac.ornl.gov/NPP/guides/xln_guide.html

Xilingol Site | NPP Page | ORNL Home Page
Revision Date: October 05, 2005
URL: http://daac.ornl.gov/NPP/guides/xln_guide.html