1

Estimation Methodology of Major Crops

by BBS

Presented bySatya Ranjan Mondal

Bangladesh Bureau of StatisticsStatistics and Informatics Division

Ministry of Planning18 October 2012

2

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.

3

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.

Contd.

4

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

5

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.

6

5. Estimation Methodology of Major Crops

Objective Method -area and yield rate estimation through 10348

sample clustersSubjective Method -area and yield rate estimation of 6 major

crops & 118 minor crops through farmers’ interview

Contd.

7

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.

8

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.

9

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.

10

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.

11

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.

12

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.

13

5. Estimation Methodology of Major Crops

C. Production Estimation (objective method)

District level production estimates are computed by the following formula:

Production (variety-wise) for the district = Area × Yield rate

Contd.

14

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.

15

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.

16

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).

17

6. Sample of crop cutting equipment

Centre

2ft 2ft. 1.625 ft.

3rd Circle (2+2+1.625 ft.)

Middle circle (Radius 2+2 ft.)

Inner most circle (Radius2 ft.)

Extendable Iron Bar 5.625 ft.

Iron Rod

Area of the circle: 100 sq. ft. 99.40Circumference: 35.34 ft.

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.

18

THANKS

19

20

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.

21

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

22

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.

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

25

Thanks