TECHNICAL METING ON THE USE OF GPS TECHNICAL METING ON THE USE OF GPS FOR CROP AREA MEASUREMENT IN THE FOR CROP AREA MEASUREMENT IN THE

AGRICULTURAL SURVEYS IN AFRICAAGRICULTURAL SURVEYS IN AFRICA

USE OF GPS FOR CROP AREA USE OF GPS FOR CROP AREA MEASUREMENT : FIELD EXPERIENCE IN MEASUREMENT : FIELD EXPERIENCE IN

NIGER ( WEST AFRICA)NIGER ( WEST AFRICA)

Addis-ABABA, Ethiopia: 27-28 November Addis-ABABA, Ethiopia: 27-28 November 20082008

By Amadou BOUREIMABy Amadou BOUREIMA

ABSTRACTABSTRACTI. I. INTRODUCTIONINTRODUCTION

II. FIELD EXPERIENCEFIELD EXPERIENCE

1. Agro-Ecologique Zones of study1. Agro-Ecologique Zones of study

2. Field team and duration of the experience2. Field team and duration of the experience

3. Materiels used and questionnaires3. Materiels used and questionnaires

4. Methodological approach4. Methodological approach

5. Outcomes/ Results5. Outcomes/ Results

6.Constraints and difficulties6.Constraints and difficulties

7. Lessons drawn7. Lessons drawn

III. Conclusion and main recommendationIII. Conclusion and main recommendation

Niger is located in West Africa : 11°40 and 23°30 N and 0°10 and 16° E with a total area of 1 267 000 km²;

Population is estimated at 13 million with a demographic growth rate of 3,3%; The economy depends essentially on uranium, the agricultural produce and Breeding;

The majority of the production is carried out by family exploitations of small sizes, turned towards the autosubsistance and whose techniques of production remain traditional;

The cultivable areas represent 12 % of the total land surface and the agricultural outputs depend primarily on the rainfall.

INTRODUCTIONINTRODUCTION

Suite Suite

This work followed upon a need expressed by FAO to test the evaluation of the areas of cultures (plots) by the use of GPS which before was done with hand Compass.

It is within this framework that the RGAC (Recensement General de l’Agriculture et du Cheptel) project whose essential aim is to update knowledge on agriculture and the breeding carried out in the end of 2005 in Niger to experiment plots surfaces evaluation by the methods of Compass and GPS.

Thus, the same national device of investigation and census of the RGAC was used on the field for the data collection.

2.1 Agro-Ecological zones of study2.1 Agro-Ecological zones of study

The tests was done in the eight regions of contry; the results presented related for 4 regions (Diffa, Dosso Niamey and of Tillabéri); The plots tests are precisely localised: in the Systems of Komadougou (Diffa), the plates of the west (Dosso), the system dunaire of the west (Tillabéri); and the valley of the river Niger (Niamey).

2.2 2.2 Field team and duration of the Field team and duration of the experienceexperience

TEAM

4 national supervisors (1 per area); 4 supervisors (1 per area); 4 controllers (1 per selected department) 8 investigators (including 2 per department).

DURATION: 21 DAYS

Choice of the owners and types of pieces 1 day ; Development and test of the questionnaire: 3 days; Formation of the implied agents: 2 days; Data-gathering on the ground: 10 days; Seizure and analyzes data: 3 days Exit of the results and development report/ratio: 2 days

Materials: GPS, compass, meter ribbon, stakes, support to be written ;

Logistics: Moto/véhicule 4x4 for displacement equips;

Questionnary: measurement of the surfaces of the plot

2.3 Materiels used and questionnaires2.3 Materiels used and questionnaires

2.4. 2.4. Methodological approachMethodological approach

1. Choice of the owners and types of plot ;

2. Development and test of the questionnaire ;

3. Formation of the agents ;

4. Data-gathering ;

5. Evaluation method of surfaces using the compass and the meter ribbon ;

6. Evaluation method of surfaces using a GPS by Navigation: For Garmin 12 XL ;

7. Method evaluation of the surfaces using a GPS by catching points (Latitude, Longitude) on the level of the angles: For Garmin 12 XL

2.5 Results2.5 Results

Basic type of data obtained (see doc) ;

Result of the comparative test for 59 plots using the three methods

Methods

Number of idem surface get with method

Number of surface get with compass who were < Surface by navigation GPS

Number of surface get by navigation GPS who were < surface get by Catch Points GPS

Boussole/Navigation GPS 1/59 soit 1,69%

35/59 soit 59,32% -

Boussole/Catch Point GPS 2/59 soit 3,38%

35/59 soit 59,32% -

Navigation GPS/Catch Points GPS 11/59 soit 17% - 27/59 soit 46 %

NB: Realized under the same working conditions

2.5 Results (suite )2.5 Results (suite )

Comparative measure of parcels with compass and GPS

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Numbers of parcels

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Comparative graph of savingComparative graph of saving of timeof time between compass-GPS and 2 Method of GPS

2.5 Results (suite )2.5 Results (suite )

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Mesure comparative des 4 GPS

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Garmin etrex_venture Garmin GPS 72 Garmin GPS 12XL Magellan_Explorist 400

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2.5 Results (suite )2.5 Results (suite )

Comparison of the surfaces measured by 4 types of GPS

Magellan Explorist 400Magellan Explorist 400

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P assage 1 P assage 2 P assage 3

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1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45P arcels n°

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Pacels n°

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Garmin Venture Etrex Garmin 72

2.5 Results (suite )2.5 Results (suite )

2.6 Constraints and difficulties

Availability of the farmer ;

Difficult access to certain pieces enclosed with thorn-bushes or flooded ;

Dependence of the daily schedule of work of the farmers concerned ;

Miss recycling of the collecting agents ;

Knowledge of data processing and the statistical concepts .

2.7 Lessons drawn

Advantages: Saving of time compared to the traditional compass method (realization of the area of 4 times a plot of approximately 3 hectares with the GPS), Direct reading of the surfaces and visual form of the plots with GPS, Precision; Less people is use on the field with the GPS, Method GPS can be made with foot, with motor bike, by bicycle or any other vehicle, gaining of other types of data (Lat/long, altitude etc); Usable what so ever the vegetative stage of the cultures ;High sensibility of Magellan Explorist 400 to evaluate important superficies

2.7 Lessons drawn (Suite)

Limits GPS: Cost is relatively higher than the compass; Require more formation ;Compass: Parcelling out of the large areas into smaller areas to determine the total surface (more error of precision); Slowness; Less precise, Can be use difficulty when cereals crops is at a higher stage and close to maturation (millet and sorghum), Require another equipment for the calculation, Require a batch of material (Meter ribbon, Jalon.....) and labour. Operator (Investigating) Risk duplication of the surfaces if the operator forgets to remove the values of the preceding pieces; Difficulty of evaluation to foot of the large surfaces; Problem of comprehension of the language of the farmer

In conclusion it is necessary to retain the following points following this experiment test:

To have a method of more effective measurement of plot which is that of the GPS;

Saving of time compared with the traditional method (method compass);

Better method evaluation of the surfaces;

Possibility of extension of methodology GPS on the pastorales enclaves which formerly are not taken into account in the evaluation of the assessment forages;

Economic, less tiresome and replicable.

III. Conclusion and main recommendation

III. Main recommendation

In recommendation, it is necessary:

Need for extension and validation of methodology GPS;

Need for generalization on the level of the other sectors;

Need for regular recycling of the agents; Need for informing in time the farmers on the work schedule; Use of the motor bikes for the large surfaces; Experience sharing with the other countries.

Mesdames et Mesdames et messieursmessieurs

Je vous remercieJe vous remercie