JOURNAL OF SCIENCE, Hue University, Vol. 67, No. 4A, 2011

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1 JOURAL OF CIECE, Hue University, Vol., o. A, LAD UITABILITY AALYI AD EVALUATIO FOR PRODUCTIO OF FRUIT TREE UIG GI TECHOLOGY A case study at Thua Thien Hue Huynh Van Chuong College of Agriculture and Forestry, Hue University Abstract. This study aimed to analyse and evaluate the land suitability for certain fruit trees in Thuy Bang commune using GI techniques in combination with a multi-criteria approach. At first, the databases for GI analyses had to be developed. The data were obtained through scientific literature review, expert opinions, interviews, and professional officers. The suitability assessment in the studied area has been done in two ways: physical suitability evaluation and social-economic, environmental suitability evaluation. Integration of GI and multi-criteria approach for land suitability analysis could be a useful methodology for further research in Vietnam. This approach makes it possible to select suitable land use types and crops for each administrative unit at community level. Keywords: Multi-criteria land suitability, fruit trees, GI, Central Vietnam. 1 Introduction There are different factors influencing the productivity of fruit trees, including cultivars, cultivation technology and the growing conditions, but first of all information has to be collected about: - appropriate farming system and evaluation of land suitability, - appropriate and advanced cultivation methods, - use of growth regulator in order to stabilise the productivity in stress situation Land suitability evaluation and agricultural land use planning are very necessary and are the basic information for right decision making afterward [2]. In order to achieve high yield and high quality of fruit trees, it is very important to select the appropriate farming system [1] and to estimate the suitable land for certain crops [], []. The constraints are mainly due to the lack of suitable land for the crop. In this regard, land suitability analysis and evaluation using GI is very important in order to determine the appropriate land for various fruit trees. The principles of sustainable development make land suitability analysis become

2 increasingly complex due to consideration of different requirements/criteria. It includes consideration of not only inherent capacity of a land unit to support a specific land use for a long period of time without deterioration, but also the socio-economic and environmental conditions. In many situations, it is extremely difficult to assign relative weights to the different criteria involved in making a decision on the suitability of land mapping unit for a land-use type. Therefore it is necessary to adopt a technique that allows an estimation of the weights. One such technique is the Analytical Hierarchy Process (AHP) [], []. As land suitability analysis requires handling both spatial and attribute data in many data layers, GI can be used to combine biophysical and socioeconomic characteristics for land evaluation and multi-criteria evaluation tool can be developed to support the decision maker in the trade-off among different stakeholders interests. Thus, an integration of GI and AHP into a multi-criteria land suitability analysis is expected to produce promising results in this research. 2 tudy area This study has chosen Thuy Bang commune in Thua Thien Hue province, central Vietnam locating at 10 E-10 E and - 2. ituated in the climate zone of hills and plains of Thua Thien Hue province, it is influenced by the common effects of tropical monsoon climatic belt with two distinct seasons. The annual average temperate is 2 0 C-2 0 C. The average annual rainfall is about 2,mm but is irregularly distributed. The rainy season is from eptember to January and accounting for 0% of total annual rainfall []. Administratively, there are villages with 1,0 households and, inhabitants; its density is 8people/km 2. There are, people in working age, of which the male labour accounts for approximately 8% and female labour 2%. As an exceptional agricultural commune, home-craft industry and services have not yet developed. Of the natural area only a small part can be used for agriculture because most of the land is sloping and has very low fertility. Materials and methods.1 Data collection patial data sources The main spatial data sources (maps) needed for this study include: (1) heets of soil map with scale 1:10,000 [8]; (2) heets of topography map with scale 1:10,000; () Current land use maps in year 0 with scale 1:10,000; () Existing land use planning maps for the period of 00-10; 1

3 () Infrastructural accessibility maps with scale 1: 10,000. () Other existing spatial databases; Attribute data sources The main attribute data sources needed for this study include the data accompanying the spatial data above and the non spatial data: (1) The data of location, climate; (2) The last census of physical and social-economic infrastructures; () The last census of agricultural production and fruit production sector; () Ecological requirements of selected fruit trees. ome available materials used for research are data on climate, geology, terrain, vegetation cover, infrastructure, socio-economy, and information about fruit trees of the area gathered from research organizations, central and local specialized organizations, agricultural expansion development centre, statistics, university libraries and provincial libraries, such as information on resource and environment, agriculture and rural development. Collected materials include annual reports, five-year summation reports, agricultural projects and research, statistical figures from communal to provincial level, and some map documents reviewing research problems gathered by the scale of 1:10,000. Inconsistent figures in the maps will be checked in reality to edit. GI software is applied on thematic map overlaying to establish databases, land unit maps and land suitability maps for selected fruit trees in two communes. Thematic maps required include: land type map, slope map, layer depth map, texture soil map, fertility map. The thematic maps are created and overlaid on Mapinfo software, then converted into ArcView software for modifying, decorating, displaying and printing. All maps occupy the scale of 1:10,000, map coordinator system UTM projection, Zone 8 orth, and datum of Vietnam 00 (V00) with its reference ellipsoid as WG.8..2 Framework of land suitability evaluation for selected crops in study area The selection and development criteria for suitability assessment in the study area have been divided into two phases: (1) physical land suitability evaluation (see Fig. Fig. 1) and then (2) social-economic, environmental suitability evaluation (see Fig. Fig. 2). In the first phase (1), the five following main physical factors were used for considering and calculating to assess the physical land suitability: soil unit type (according to FAO soil classification system), soil texture, soil effective depth, soil slope degree, and soil fertility.

4 Database oil lope oil depth oil texture oil fertility Overlap GI oftware: Mapinfo; ArcView oil fertility map oil depth map oil texture map lope soil map oil map Attribute data Table, Graph Export to Excel, Access Import from Excel, Access Land Evaluation Units Map Crop requirements Output Physical land suitability map for each fruit crops Fig. 1. Chart of GI applications to physical land suitability evaluation for crops Map and attribute data Physical land suitability map ocial-economic, environmental database Economy-Infrastructure ociety Environment Questionnaires, interview, expert knowledge, statistic data Analysis Hierarchy organization of criteria Analytical Hierarchy Process (AHP) GI Final uitability map for each fruit crop Proposals and Recommendations Fig. 2. chematic chart of social-economic and environmental suitability evaluation In the second phase (2), the selection, development and hierarchical organization of criteria and sub-criteria for social-economic and environmental suitability evaluation is shown as Table 1.

5 In order to obtain the importance of evaluative criteria and weightings for integrating into GI context, the AHP technique of [, ] was used. There are three steps for this technique: - The first step of AHP technique is to structure the overall goal (land suitability) into a number of criteria and sub-criteria in a hierarchy. - The second step of AHP technique involves comparison of the alternatives, criteria and sub-criteria. They are compared in pairs with respect to each factor of the next higher level. - The last step of AHP technique is to synthesize the comparisons to get the priorities of the alternatives with respect to each criterion and the weights of each criterion with respect to the goal. Once the weight value (see Table 1) has been assigned for each class of each map, all maps of factors for each land use type will be multiplied together. This study conducted calculations of the weight and fact value of each criterion and sub-criterion, produced the theme layers of each sub-criterion, overlaid all the theme layers for having the final suitability classification. Table 1. Weights of criteria for land suitability evaluation for selected fruit trees in Thuy Bang 1. Economyinfrastructure 2. ociety Criteria ub-criteria Overall weights W 1 W i (wi = w1 x w2) Rural road systems Irrigation and drainage Transportable vehicles and agri-implements torage and processing Market channels Benefit/Cost W Labour availability Capital resources Price and market Farmer s technology skills Cultivation habits of tate policy for Cultivated land per capita

6 . Environment W.1 Physical conditions oil coverage level Water source protection Bio-diversified level um tandardization of the criteria maps: This process of setting the relative importance of classes of criteria into GI is called standardization. ome sub-criteria can be represented by the GI layer and some are purely non spatial. The formula for calculating the suitability index of each layer as follow: Where W i : i = X i x W i weight of the each criterion, as presented in AHP techniques above. X i : fact value of each criterion, an example of X i is showed in Table.. i : suitability index. Value or score (X i ) of each level of criterion is computed for each evaluated land unit. cores for the social-economic, physical environment criteria were calculated basing on expert and farmer opinions as well as local conditions derived from questionnaire, seminar and discussion. Results and discussion.1 Thematic maps and the evaluated land units map in the study area Basing on the above-mentioned objective and the fact condition of the study area, the research puts forward the criteria to set up thematic maps for evaluated land unit map including: soil classification (see Fig. a), soil sloping, soil layer depth, soil texture, soil fertility (level of nitrogen, phosphorus, potassium, ph KCL, organic matter) and current land use structure. In addition to these criteria, in order to establish a more detailed thematic map, the study also pays attention to other criteria, but in terms of non-spatial data. These data are generalized and analyzed for the whole area without being separated for evaluated land units. After overlaying thematic maps with the support of the specialised GI software, there are 2 land units found on the map of Thuy Bang commune with the scale of 1: The detailed information on the properties of the 2 land units is presented in Fig. b.

7 oil Units Map Thuy Bang commune - Huong Thuy district- Thua Thien Hue province GLp ACr ACl cale: 1/10,000 Thuy Bieu commune FLa GLa CMs ACh soil type map_region.shp Arenic-Acrisols Arenic-Fluvisols Arenic-Gleysols Endogleyic-Acrisols Episkeletic-Leptosols Gleyic-Acrisols Haplic-Acrisols Leptic-Acrisols Leptic-Cambisols Plinthic-Gleysols Rhodic-Acrisols keletic-cambisols keletic-leptosols ACg LPs ACg1 CMl LPs2 ACa W Duong Hoa commune E Phu on Commune Land Unit Map Thuy Bang commune- Huong Thuy district- Thua Thien Hue province 2 Land evaluation units map 1_region.shp Duong Hoa commune cale: 1/10,000 Thuy Bieu commune a) b) W E Phu on commune Fig.. The map of soil units classification and evaluated land units of Thuy Bang commune The data in Fig. reveal a fact that although the area of the commune is not too large, the number of land units found is rather much. The area of each land unit varies greatly, from 0.0ha to 281ha. Large number of land units also means that there is a big difference in the characteristics of soil criteria in a small area of land, and there is no homogeneity. This is a distinctive feature of the hilly land in Central Vietnam in comparison with other regions..2 Presentation of the physical land suitability evaluation for the selected fruit trees To classify the physical land suitability level for crops is to compare the ecological requirements of that crop with the characteristics of each evaluated land unit. The suitability classification results are shown in Fig. a for citrus fruitsand and Fig. b for mangosteen. Land suitability classification always include the limitation factors affecting the growth, development and productivity of fruit crops. From Fig. a, it can be seen that six land units are at level 2 (, 12,,, 2, 2), 8 land units are at level (1,,,, 8,,, ), and the other land units are not suitable for citrus fruits. uitability levels of mangosteen reveal (Fig. b) that among the evaluated area of Thuy Bang commune, there is no area at level 1; therefore, similar to citrus fruits, the land here has some limitations that affect the growth, development and productivity of mangosteen. The level 2 has 10.02ha, accounting for % of the total area, three land units (12,, 2) are at this level, the limitations of 2 consist of 2 dominant factors (soil type and slope) and 2 ordinary factors (soil fertility and soil texture) which can be improved during the process of 1

8 cultivation. The level has.ha (21.% of the total area), six land units (1,,,,, ) are at this level, the limitations of include dominant factors (soil type, slope and soil layer depth) which are difficult to improve and 2 ordinary ones (soil texture and soil fertility) which can be upgraded by technical measures. The area of non-suitability level is 1,.ha, accounting for.% of the total area, the main causes for this non-suitability are soil types and soil layer depth, and there are land units that are not suitable for growing mangosteen. The maps of current physical land suitability for citrus and mangosteen tree are stored in the GI software. The Map of Current Physical uitability for Citrus Fruit Thuy Bang commune- Huong Thuy district- Thua Thien Hue province cale: 1/10,000 W E Thuy Bieu commune a) b) The Map of Current Physical uitability for Mangosteen Thuy Bang commune- Huong Thuy district- Thua Thien Hue province cale: 1/10,000 Thuy Bieu commune Phu on commune W E Duong Hoa commune Phu on commune Duong Hoa commune Land suitability for citrus fruit 0-final_region.shp 2p 2slp 2tp 1 dtp Area (in ha) 0% gdp gdtp gsltp gtp sltp 1% % 2% Land suitability for mangosteen 0_final_region.shp 2g.sl.p 1 2 2t Area (inha) 0% % g.d.p g.sl.t.p g.t.d.p g.t.p sl.p 2% 1 2 2% Fig.. The map of current physical land suitability classification for fruit trees. Presentation of the social-economic and environmental land suitability evaluation The social-economic and environmental suitability assessment is only conducted on those land units with result of physical suitability level of 1, 2, and. The identification of main criteria and sub-criteria in this phase reveals that the final suitability assessment is rather complicated. As each criterion has a different role, the weight of each criterion was worked out to estimate the influence of each criterion to the final result. From the results of physical land suitability evaluation and the results of the methodology-mentioned multi-criteria analysis, by overlaying the attributive information of sub-criteria, the final results of land suitability for citrus fruits and

9 mangosteen fruit tree in Thuy Bang commune are presented in Fig. a and b. By applying multi-criteria method in land suitability assessment for selected fruit trees in Thuy Bang commune, Thua Thien Hue province, the study has identified different levels of suitability of land units for selected fruit trees. According to Fig. a, the limitations and difficulties relating to natural and socio-economic conditions have resulted in 0ha of level 1 for citrus fruits. Level 2 has.ha (.1%). Level has 1.2ha (.1%). According to Fig. b, the limitations and difficulties relating to natural and socio-economic conditions have resulted in 0ha of level 1 for mangosteen. Level 2 has.ha (.%). Level has 0.00ha. The area of unsuitable land for mangosteen in Thuy Bang is 2.2ha (.%). The uitability M ap for C itrus Fruits Thuy Bang commune -H uong Thuy district-thua Thien Hue province c a le : 1 :/1 0,00 0 Th e u itab ility M a p fo r M a n g o stee n Thu y B ang com m une- Huong T huy district- Thua T hien Hue provin ce c a le : 1 /1 0, Thuy Bieu com mune W E 2 2 Thuy Bieu com m une W E D uo ng H o a c o m m u ne Phu on commune Ph u on com m une D u o n g H o a c o m m u n e Econom ic -social-physical suitability for citrus fruit 0_ region.shp 2 1 Area (ha) 0% 2 % Econom ic -social- physica l suitability for m angosteen tree 0 _ region.shp 2 Area (ha) 1 0% 2 2% 0% 0% 1 2 % % 1 2 Fig.. uitability map for selected fruit trees in Thuy Bang commune Thuy Bang commune with the total natural area of 2,28ha has 2 land units. The study carried out the classification of physical land suitability for citrus fruit and mangosteen. The suitability classification results are shown in Fig. a and b. In the table of land suitability classification always attach the limitation factors affecting the growth, development and productivity of fruit trees. For example, d.t.p in the second row of Fig. a means that land unit of number one is low suitable () for citrus fruits with the limitation factors including soil depth (d), soil texture (t), and soil fertility (p). Conclusion The multi-criteria suitability land evaluation method, together with GI technology for selected fruit crops is highly feasible and appropriate at communal level. 21

10 It could be further expanded to other communes with similar conditions in Central Vietnam. The productivity of fruit trees at the study area is influenced by climate, soil and edaphically growing factors. The yield potential of selected fruit trees and cultivars can be exploited if these factors are optimal or the cultivation technology is well adapted. With the help of a multi-criteria analysis the final land suitability maps for the different group of fruits can be developed. In this research region, it is not easy to find land for fruit trees belonging to the high suitability-1 classification. References 1. Dixon J., Glulliver A., Gibbon D, Farming system and Poverty Improvemrnt Farmer s livelihood in changing world FAO and Word Bank, Rome, Italy, Principle Editor Malcolm Hall, FAO., Guideline for land use planning: FAO development series 1, Vol.8 (): Food and Agriculture Organization of the United ations, Rome, (1), 0-.. Huynh, V. C and M. Boehme, Evaluation of physical land suitability for the "Thanh Tra" pomelo crop in Hue, Vietnam: Conference on International Agricultural Research for Development, Tropentag October, (0), -.. Huynh. V. C., M. Boehme and M. La Rosa Perez, ocial-economical Database Implementation into GI to Analyse Land uitability for Citrus Fruit Production: A Case tudy in the Thua Thien Hue Province, Vietnam, In: Deutscher Tropentag, International Research on Food ecurity, atural Resource Management and Rural Development, Bonn, Germany, 0.. guyen, V, Climatic data in Thua Thien Hue recorded from 1 to 18, In: Report on results of climate research in Thue Thien Hue, Hue, -2, 1.. aaty, T. L., A scaling method for priorities in hierarchical structure: Journal of Mathematical Psychology., (1), -.. aaty, T. L, Fundamentals of decision making and priority theory with the analytic hierarchy process: RW Publications, Pittsburgh, Vol., (00), Thua Thien Hue DT-Thua Thien Hue Department of cience and Technology., Investigating and establishing the soil-fertility map for some hilly communes of Thua Thien Hue province (in Vietnamese), In: Report of Thua Thien Hue Department of cience and Technology, Hue, (0), 1-.