NPP Grassland: Lamto, Ivory Coast, 1965-1987

Summary:

Climate data for this site are also available: see Any Other Relevant Information in section 11 of this document.

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:

Introduction:

The grass savanna occurs within a mosaic of grass, shrub and tree savannas distributed according to drainage, slope and micro-topology (Menaut and Cesar, 1979; Abbadie et al., 1992). Loudetia spp. predominate in the grass savanna, whilst Andropogoneae (Hyperrhenia spp.) provide the main grasses in the shrub and tree savannas. Grasses make up the majority of NPP, even in the tree savanna, where tree root turnover seems to contribute little to NPP. Total net primary production (NPP) of the grass savanna has been estimated at 2150 g m-2, of which 1320 g m-2 (61%) is below-ground production. Normally 50-90% of above-ground grass biomass is burned annually, i.e. more than half of above ground grass production.

Objective/Purpose:

Summary of Parameters:

1. Site

2. Treatment

3. Year

4. Month

5. Day

6. Date in decimal year

7. Above ground biomass

8. Standing dead

9. Litter

10. Above ground total matter

11. Below ground total matter

12. Carbon/nitrogen ratio of above ground biomass (calculated)

13. Carbon/nitrogen ratio of standing dead matter (calculated)

14. Carbon/nitrogen ratio of below ground total matter (calculated)

Discussion:

Related Datasets:

2. Investigator(s):

Investigator(s) Name and Title:

Title of Investigation

Contact Information:

3. Theory of Measurements:

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:

• soil corer
• quadrat sampling frame
• laboratory balance

Collection Environment:

Platform/Source:

Platform/Source Mission Objectives:

Key Variables:

Below-ground live/dead root biomass;

Principles of Operation:

Sensor/Instrument Measurement Geometry:

Manufacturer of Sensor/Instrument:

Calibration:

Specifications:

Tolerance:

Frequency of Calibration:

Other Calibration Information:

5. Data Acquisition Methods:

Dry weight of each above ground category was determined each month by clipping to ground level within 16 quadrats of 1.0 m2, selected randomly from a total of 192 potential quadrat locations. Clipped material was immediately sorted into live and standing dead, and litter (fallen dead matter) was harvested from the ground. Samples were weighed fresh before drying.

Below-ground plant matter was sampled by extracting blocks of soil, 20 cm x 20 cm, in successive 10 cm layers to 1.0 m depth. The soil was considered too gravely and too hard in the dry season to permit use of soil augers or corers (gouges). Only four soil blocks were sampled per month. 80% of root biomass was found in the top 30 cm. Soil cores were washed over a 2 mm sieve, and live and dead roots were separated from only one soil block per month.

All sorted plant matter was weighed fresh before oven drying to constant weight at 95 C.

Decomposition above-ground was accounted for by estimating a mean monthly disappearance rate for leaf litter (7.6% for Loudetia savanna) according to the methods of Weigert and Evans (1964) and Lomnicki et al. (1968).

6. Observations:

Data/Field Notes:

site elevation (m): Data Not Available

mean annual precipitation (mm): 1164.9

mean monthly min temperature (C): 21.5 (Jan)

mean monthly maximum temperature (C): 35.8 (Feb)

vegetation type: humid savanna

dominant species: Loudetia simplex (C4 photosynthetic type)

historical long-term management regime (estimated): annual burning in February

maximum aboveground live biomass (typical month): 450 g m-2 (Nov)

soil type: ferruginous hydromorphic pseudogley

soil pH: 6.0

soil texture (sand/silt/clay): 0.85/ 0.10/ 0.05

soil carbon content: 1800 g/m2 (0-20 cm)

soil nitrogen content: 150? g/m2 (0-20 cm)

7. Data Description:

Spatial Characteristics:

Spatial Coverage:

Spatial Coverage Map:

Spatial Resolution:

Projection:

Grid Description:

Temporal Characteristics:

Temporal Coverage:

Temporal Coverage Map:

Temporal Resolution:

Data Description:

Parameter/Variable:

There are fourteen (14) parameters for each of these 2 datasets. There are 2 treatments at this site, but the same types of data were collected for each treatment and both data files are presented in exactly the same format. Items 1-2 refer to the site and the treatments, respectively. Minimum and maximum values for the remaining parameters are for the combined treatments.

1.
variable=Site
definition=site where data were gathered
code=kln: Lamto

2.
variable=Treatmt
definition=long term management of site
code=lngt_2: annual burning in February; burned February each year
code=lngt_3: annual burning in February; burned at the end of January?

3.
variable=Year
definition=year in which data were collected
units=year
minimum=1969
maximum=1987

4.
variable=Mn
definition=month in which data were collected
units=month
minimum=01
maximum=12

5.
variable=Dy
definition=day in which data were collected
units=day
minimum=15
maximum=15

6.
variable=Tyear
definition=Date in decimal year
units=year plus the Julian date divided by 365
minimum=1969.288
maximum=1987.203

7.
variable=AGbiomass
definition=Above ground live biomass
units=[g][m^-2]
minimum=10
maximum=560

8.
variable=Stdead
definition=Standing dead
units=[g][m^-2]
minimum=0
maximum=275

9.
variable=litter
definition=dead biomass found above ground
units=[g][m^-2]
minimum=0
maximum=52

10.
variable=AGtotmatter
definition=above ground total matter
units=[g][m^-2]
minimum=0
maximum=792

11.
variable=BGtotmatter
definition=below ground total matter
units=[g][m^-2]
minimum=646
maximum=2350

12.
variable=CN_AGB
definition=Carbon/nitrogen ratio of above ground biomass
units=dimensionless
minimum=41.0
maximum=176.0

13.
variable=CN_STD
definition=Carbon/nitrogen ratio of standing dead matter
units=dimensionless
minimum=78.0
maximum=138.0

14.
variable=CN_BGT
definition=Carbon/nitrogen ratio of below ground total matter
units=dimensionless
minimum=85.0
maximum=119.0

Sample Data Record

                                                                           
Site   Treatmt   Year   Mn   Dy   Tyear     AGbiomass   Stdead   litter         
------------------------------------------------------------------------        
lmt     lngt_2   1969   04   15   1969.288   230.0       0.0     -999.9         
                                                                                
                                                                                
AGtotmatter   BGtotmatter                                                       
--------------------------                                                      
230.0          1680.0                                                           

8. Data Organization:

Data Granularity:

1. Data File lmt_npp.txt 9.0 KBytes
Period: 15 Apr 1969 through 15 Mar 1987
Latitude: 6.22N, Longitude: 5.03W

2. Data File lmt2_npp.txt 1.5 KBytes
Period: 15 Apr 1969 through 15 Mar 1987
Latitude: 6.22N, Longitude: 5.03W

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

Data Format:

Site;Treatmt;Year;Mn;Dy;Tyear;AGbiomass;Stdead;litter;AGtotmatter;BGtotmatter [units g/m2]; CN_AGB;CN_STD;CN_BGT [units dimensionless]  

lmt;lngt_2  ;1969;04;15;1969.288; 230.0;   0.0;-999.9; 230.0;1680.0;-999.9;-999.9;-999.9
lmt;lngt_2  ;1969;05;15;1969.370; 300.0;   0.0;-999.9; 300.0;1840.0;-999.9;-999.9;-999.9

9. Data Manipulations:

Formulae:

Derivation Techniques and Algorithms:

Data Processing Sequence:

Calculations:

Graphs and Plots:

10. Errors:

11. Notes:

Limitations of the Data:

Known Problems with the Data:

Usage Guidance:

12. Application of the Data Set:

Although discontinuous, the detailed monthly above and below ground biomass data obtained for the Lamto grass savanna are particularly suitable for validation of models running on a monthly time step.

13. Future Modifications and Plans:

14. Software:

Software Description:

Software Access

15. Data Access:

Contact Information:

Telephone: 865-241-3952
Email Address: ornldaac@ornl.gov

Data Center Identification:

Telephone: 865-241-3952
Email Address: ornldaac@ornl.gov

Procedures for Obtaining Data:

Data Center Status/Plans:

16. Output Products and Availability:

17. References:

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.

Lomnicki, A., E. Bandola and K, Jankovska (1968) Modification of the Weigert-Evans method for estimation of net primary production. Ecology 49, 147-149.

Long, S.P. and Mason, C.F. (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.

Menaut, J-C. 1979. Net Primary Production for Lamto (Ivory Coast) Grassland Site Dataset, In Menaut, J-C. and J. Cesar (1979) Structure and primary productivity of Lamto savannas, Ivory Coast. Ecology 60, 1197-1210.

Menaut, J-C. and J. Cesar (1979) Structure and primary productivity of Lamto savannas, Ivory Coast. Ecology 60, 1197-1210.

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

Parton, W.J., J.M.O. Scurlock, D.S. Ojima, T.G. Gilmanov, R.J. Scholes, D.S. Schimel, T. Kirchner, J-C. Menaut, T. Seastedt, E. Garcia Moya, Apinan Kamnalrut and J.I. Kinyamario (1993) Observations and modeling of biomass and soil organic matter dynamics for the grassland biome worldwide. Global Biogeochemical Cycles 7, 785-809.

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.

Weigert, R.G. and F.C. Evans (1964) Primary production and the disappearance of dead vegetation on an old field in south-eastern Michigan. Ecology 45, 49-63.

18. Glossary of Terms:

A general glossary for the DAAC is located at http://cdiac.esd.ornl.gov/cdiac/glossary.html.

A glossary of EOSDIS terms is available at http://www-v0ims.gsfc.nasa.gov/v0ims/glossary.of.terms.html.

19. List of Acronyms:

The EOSDIS Acronym and Abbreviation List is located at http://www-v0ims.gsfc.nasa.gov/v0ims/acronyms.html

20. Document Information:

Document Revision Date:

Review Date

Document ID:

Citation:

Document Curator:

Document Author:

Document URL: