Transcript Slide 1

Estimation Methodology of
Major Crops
by BBS
Presented by
Satya Ranjan Mondal
Bangladesh Bureau of Statistics
Statistics and Informatics Division
Ministry of Planning
18 October 2012
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1. Introduction
 According to the allocation of Business of the
Govt. of Bangladesh, Bangladesh Bureau of
Statistics (BBS) is responsible to collect,
compile and disseminate all types of official
statistics.
 BBS estimates area, yield rates & production
statistics of 124 crops as well as land use and
irrigation statistics, crop damage statistics etc.
Contd.
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2. System of Agricultural Statistics
a. Census (Structural Statistics)
 total number of farm holdings
 size of farm holdings
 land ownership
 land tenancy
 area under permanent and temporary
crops
 homestead area
 agricultural equipments
 livestock & fisheries etc.
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3. System of Agricultural Statistics
b. Sample survey (annual/seasonal)
 annual agricultural crop statistics
 land use and irrigation statistics
 agricultural labour wage statistics
 cost of production statistics of important crops
 crop damage statistics
 forecasting of major crops
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4. Estimation of Annual/Seasonal
Crop Statistics
 At district level: area, yield rates, and
production statistics of 6 major crops for 64
districts
- Aus, Aman, Boro, Wheat, Jute and Potato
 At region level: area, yield rates, and
production statistics of 118 minor crops 23
regions
-Pulses, Oilseeds, Fruits, Vegetables, Spices
etc.
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5. Estimation Methodology of Major Crops
 Objective Method
-area and yield rate estimation through 10348
sample clusters
 Subjective Method
-area and yield rate estimation of 6 major
crops & 118 minor crops through farmers’
interview
Contd.
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5. Estimation Methodology of Major Crops
a. Area Estimation (objective method)
 Coverage
- 10348 sample clusters
- Sampling fraction 1/ 520
- Average size of a cluster: 5 acres
- Clusters are allocated by Probability Proportionate
to size (PPS) of the districts
Contd.
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5. Estimation Methodology of Major Crops

Data collection from cluster:
- field staff visit the clusters during
the growing stage of the crops
- visit the clusters 4 times a year to
capture the 6 major crops
- record the data on land use (crops and
others)
Contd.
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5. Estimation Methodology of Major Crops

Area Estimation method
Area for a crop for the district =
Effective Area for the district ×
Area Ratio devoted to the crop for the district
Where, Effective Area = (total land area – urban area –
govt. reserved forest area – big rivers area).
Area ratio devoted to the crop for the
district=(sum of area devoted to the crop from
plots within the clusters for the district) ÷ sum of
areas of corresponding clusters for the district
Contd.9
5. Estimation Methodology of Major Crops
b. Yield Estimation (objective method)
Conduct sample crop cutting experiments
(at least 10 cuts per upazilla)

Within the clusters

Variety (local, HYV, hybrid etc.)

Number of cuts proportionately

Area of each cut = 99.40 sq. ft.
Contd.
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5. Estimation Methodology of Major Crops
 After cutting and threshing of the crop (e.g.
paddy)
- get the total green weight
- measure moisture
- obtain the final dry weight
Contd.
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5. Estimation Methodology of Major Crops
 Take the simple average of all cuts in a
district (paddy).
 Obtain the final yield rate in rice.
 Yields are estimated by variety
- local
- HYV
- hybrid
Contd.
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5. Estimation Methodology of Major Crops
C. Production Estimation (objective method)
District level production estimates are computed
by the following formula:
Production (variety-wise)
= Area × Yield rate
for
the
district
Contd.
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5. Estimation Methodology of Major Crops
 For potato crop


two sample rows are selected in a cluster (or
in a selected plot).
area under sample rows is measured.
potato of sample rows is harvested and yield
is estimated accordingly.
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5. Estimation Methodology of Major Crops
 For jute crop green plants are cut in a circular area of 50 sq.
ft.
 the cut plants are retted separately.
 dry weight is recorded after peeling, washing
and drying.
 For wheat crop cutting experiment is done by taking a circular
area of 50 sq. ft.
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6. Validation of the Estimation
Validation by farmer’s interview method (subjective
method)
 Select one mouza from each union by SRS.
 Listing all farmers in the mouza.
 Identifying the farmers cultivating respective crops.
 Select five farmers (3 small, 1 medium & 1 large)
from that mouza by SRS.
 Interview the farmers: record area and production of
a crop of current year and last year.
 Obtain the district level area and yield rates of the
crop by ratio estimate to make comparison with
objective method (cluster method).
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6. Sample of crop cutting equipment
Iron Rod
Extendable Iron Bar 5.625 ft.
2ft
2ft.
Centre
1.625 ft.
Inner most circle (Radius2 ft.)
Middle circle (Radius 2+2 ft.)
3rd Circle (2+2+1.625 ft.)
Area of the circle: 100 sq. ft. 99.40
Circumference: 35.34 ft.
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Precision of the Estimates
 95% confidence level for area estimates at
district level are considered.
 Aus, Wheat, Jute and Potato crops are getting
smaller, so the total sample design is being
reviewed under a project funded by FAO.
 At present the SE for estimates are not
computed; after reviewing the whole process, it
is planned that the SE/ Design Effect are to be
computed.
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THANKS
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7. Estimation Methodology (Subjective Method)
a. Estimation of area (ratio estimate)
Total area (under a crop for the union)= (X/Y) × total area under
the crop of the union in last year
where X= total area cultivated by 5 farmers for the current year
and Y= total area cultivated by 5 farmers for the last year
Contd.
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7. Estimation Methodology (Subject Method)
b. Estimation of production (ratio estimate)
Total production (under a crop for the union)= (X/Y) ×
total production under the crop of the union in last
year
where X= total crop produced by 5 farmers for the
current year and Y= total crop produced by 5 farmers
for the last year
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8. Estimation Methodology of Perennial
Minor Crops
Estimation Procedure
 Select one mouza from each union by SRS.
 List the household (max. 250).
 Interview and record the data: no. of tree
(e.g. mango, jackfruit, litchi etc.), yield per
tree, area of garden (if any) etc.
 Obtain the average no. of tree per
household, average yield per tree etc. for
the union.
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9. Recent Development & Future Plan
Recent Development
 Expansion and updating the sample clusters
 BBS conducts crop cutting in presence of
DAE officials
 Moisture measuring machine is used to
record the humidity of sample crops
 Consultation meeting with DAE, SPARRSO,
& FPMU for important crops
 Training of field staff
Contd.
9. Recent Development & Future Plan
 Future Plan
 Database of agricultural statistics
 Automation in data processing
 Conduct surveys on productivity of crops, cost
of production etc.
 Conduct surveys on livestock, fisheries and
forest areas
 Capacity building
Thanks
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