Duishonakunov M. T.*, Luu The Anh**

* Faculty of Geography and Ecology of Kyrgyz NationalUniversity (КырНУ)

** Researcher, Institute ofGeography (IG) Vietnamese Academy of Science and Technology (VAST)

LAND SUITABILITY EVALUATION FOR DEVELOPMENT OF AREA SPECIALIZING IN COFFEE CULTIVATION USING THE INTEGRATED ALES - GIS MODEL

(A CASE STUDY IN BUON MA THUOT PLATEAU, DAKLAK PROVINCE– VIET NAM)

Introduction.Coffee is an important exportcrop from Viet Nam. The current coffee area is about 500,000 ha over thecountry; in which coffee area of Buon Ma Thuot plateau is about 258,498 ha(occupy 51.7% of total coffee area of country). The unsustainable developmentof coffee area in the past decade has led to inefficient use of naturalresources, land degradation, poverty and other social problems. A number of studieson soil survey, land evaluation and land potential classification have beencarried out throughout the country, but most of this studies used conventionalmethods which require more time and high cost. In recent year, with thedevelopment of information technology, GIS technology is broadly applied inland survey and land evaluation studies. This paper presents result of landsuitability evaluation for coffee in Buon Ma Thuot plateau using the integratedALES - GIS model which involves the FAO’s land suitability classificationmethod along with expert knowledge.

Generaldescription of the study area. The study area is the biggest basalt plateau which is located in theCentral Highland of Viet Nam. The altitude of plateau ranges from about 400 mto 800 m above mean sea level. Geologically, this area comprises Neogene andPleixtoxen volcanic rocks. Based on the result of soil survey was conducted inperiod of 2000 - 2003 under FAO/WRB soil classification system, soil resourcesof Buon Ma Thuot plateau consists of 5 groups and 17 types (Gleysols: 4 soiltypes, Luvisols: 5 soil types, Phaeozems: 2 soil types, Ferralsols: 5 soiltypes, Leptosols: 1 soil types). This area is affected by plateau tropicalmonsoon weather condition with 2 main seasons, dry and rainy. Mean annualrainfall ranges between about 1600 and 1800 mm, mean annual temperature isaround 21 - 25⁰, annual evaporation is around 1300 - 1500 mm.

Methodand approaches. AutomatedLand Evaluation System (ALES) version 4.65 is integrated with GIS softwares asa technique for land suitability evaluation in this study. ALES uses landcharacteristics required for plant growth. Decision Tree in ALES matchesbetween Land Qualities and Land Characteristics with the criteria of land evaluationat study scale of 1:50,000 based on FAO’s Guidelines for Land Evaluation. Theland qualities to be used in this evaluation thus include a number of landcharacteristics viz., 5 soil groups (SG); 3 surface coarse fragment classes(SCF), 3 subsurface coarse fragment classes (SSCF); 3 organic matter classes(OM); 11 soil textural classes (ST); 4 soil depth classes (SD); 8 pH classes(PH); 6 soil slope classes (SL); 4 drainage classes (DR); 6 mean yearly maximum temperature classes (MYMAXT); 6 meanyearly minimum temperature classes (MYMINT); 13 mean yearly temperature classes (MYT); 3 meanyearly radiation classes (MYRAD); 6 mean yearly rainfall classes (MYR); 3 number ofrainy months classes(RM) and 6 number of dry months classes (DRM).  A landmapping unit resulting from the overlay process of the selected theme layershas unique information of land qualities for which the suitability is based on.The theme layers were collected from existing information and satellite data.Analysis of rainfall data and irrigation area give the water availability.Spatial information of nutrient availability was formulated using soil map ofNational Institute for Agricultural Planning and Project. Landform of the areawas prepared from Landsat ETM and topographical map. Soil physical and chemicalproperties are based on the result of soil sample analysis. Each of the abovementioned layers with associated attribute data were digitally encoded in a GISdatabase to create thematic layers. Overlay operation on the layers produce a resultantpolygonal layer, each of which is a land unit with characteristics of the land(fig. 1). Land suitability rating model applied to the resultant polygonallayer provided the suitability classes for coffee crop. The resultantsuitability classes were checked against the coffee field.

Fig. 1  Flowchart of the ALES – GIS model applicationin land suitability evaluation for coffee crop

Suitability classesof FAO Framework of land evaluation:

S1: Highly suitable.Represents land having no significant limitations to sustained application ofthe defined use.

S2: Moderately suitable.Represents land having limitations, which will reduce production level and/ orincrease costs, but is physically and economically suitable for the defineduse.

S3: Marginallysuitable. Represents land having limitations, which will reduce productionlevels and/ or cost such that it is economically marginal for the defined use.

N: Not suitable, itmainly distinguishes land that is unsuitable for a particular use.

Resultsand discussion. Matching land use requirement andland qualities and characteristics of LMU in ALES software obtains thesuitability classes for each LUM. The result of evaluation process is exportedto GIS for mapping of land suitability map of Arabica and Robusta coffee cropswhich is presented in table 1.

Table1   Land suitability area for Arabica and Robustacoffee crops

Thestudy provides an approach to identify parametric values in modeling the landsuitability for agricultural development. The theme layers to be input the modelingare assigned the rating value as attribute data. Overall insight into thefactors affecting the suitability of land can be provided spatially andquantitatively. It has become increasingly apparent that computer based IGS canprovide the means to model land suitability effectively.

Inconclusion, with the integrated ALES - GIS model, it is possible to conduct spatialanalysis and to assess the land suitability with higher accuracy and economy.In addition, the model provided an approach to the improvement of yield byenhancing the component of modeling input.

References

1. FAO, 1976. A frame work for land evaluation. SoilBulletin, No. 32, Rome.

2. FAO, 1983. Guidelines: Land evaluation for rainfedagriculture. Soil Bulletin, No. 52, Rome.

3. FAO, 1998. World Reference Base for Soil Resources.Rome: Food and Agriculture Organization of the United Nations.

4. Rossiter D.G., 1994. Lecture notes: Landevaluation. Cornell University, College of Agriculture and Life Sciences,Department of Soil, Crop and Atmospheric Sciences.

5. Rossiter D.G. & Van Wambeke A.R, 2000.Automated Land Evaluation System ALES Version 4.65 User’s Manual, Department ofSoil, Crop & Atmospheric Science. SCASeaching Series No. T93-2 Revision 6.Ithaca, NYUAS.

6. Do N.X., Huan N.C., Ky N.D., Anh L.T. & ThinhN.A., 2005. An integrated ALES - GIS model in landscape evaluation forcultivated crops (In case study: coffee, rubber area in Daklak and Daknongprovinces. Soil Science Journal, No. 23/2005. Vietnam Soil Science Society.