پديد آورندگان :
ثروتي، مسلم دانشگاه اروميه , پيشنمازاحمدي، مجيد دانشگاه تبريز - گروه جغرافيا و برنامه ريزي , ممتاز، حميدرضا دانشگاه اروميه - گروه علوم و مهندسي خاك , حسنلو، مصطفي دانشگاه اروميه
چكيده لاتين :
Introduction Land suitability mapping is a prerequisite to achieving optimum utilization of the arable land resources. In Besides, one of the top agricultural policies, is land evaluation suitability of arable land and agricultural potential in order to support current and future agricultural uses. Also ,land suitability evaluation and soil mapping is necessary. This study was conducted, adopting a case study which Ideal Point models the opportunities for barley production under irrigation conditions in the Horand region, north-west of Eastern Azerbaijan Province, Iran.
Materials and Methods The study area with 712 ha extension is located in Eastern Azerbaijan province, eastern longitude of 706022 to 712105m and northern latitude of 4303167 to 4304337m UTM. The soil moisture and temperature regimes were xeric and mesic, respectively. Soil morphological, physical and chemical characteristics of 36 soil profiles were studied. For this purpose, a number of soil and landscape properties were identified in the literature and their weights on irrigated barley production wewe specified as with local experts. The physical and chemical characteristics were texture, active soil depth, available water holding capacity, surface stones, soil organic matter, cation exchange capacity, calcium carbonate, EC, alkalinity, pH, infiltration rate and soil drainage. Slope and Soil erosion were taken into consideration in the study region because those parameters limit irrigated barley yield. Important climate properties including mean temperature of the growing cycle and relative humidity were not the used in this models, because these properties are not limiting parameter for irrigated barley growing in the study region. To derive the land suitability evaluation for barley based on Ideal Point mapping, the weighted map layers created are applied as the input data. Land suitability maps for each crop were created as a continuous scale ranging from 0 to 1. Composite operator was used to compare the resulting maps from the use of the Ideal Point approaches and observed yield. The composite operator showed some merits that the other operator lacked, the most important being that product the distinct matrix when a soft-classified map is compared to itself.
Results and Discussion According to keys to soil taxonomy 2014, the studied soils were classified in Alfisols, Inceptisols and Entisols. Based on the local expert’s studies and Analytical Hierarchy Process (AHP), soil and landscape properties are the most sensitive alternative in the land suitability evaluation classification for irrigated barley in the study region. Therefore, the local experts allocated higher weights to soil and landscape properties than to other properties. However, the accuracy of the results of land suitability evaluation is dependent on the designated weights for soil properties given by experts. The results showed that soil texture, soil reaction and soil carbonate are considered the most significant properties in the study region because they have higher weights than other properties. The results of the soil relative weights calculated by AHP methods were acceptable for application in ideal point land suitability evaluation with the ratios of less than (0.1). In present study, 6 candidate continuous scales ranging from 0 to 1 classes in the study region were selected for irrigated barley land suitability evaluation by overlaying data layers (digital maps) and query functions in Arc GIS 9.2. Land suitability evaluation of susceptible lands using Ideal point model revealed that 2.97, 17.16, 18.23, 48.86, 8.01 and 4.77 of the total area can take place in 0.2-0.3, 0.3-0.4, 0.4-0.5, 0.5-0.6, 0.6-0.7 and 0.7-0.8 continuous scale ranging class, respectively. The results of the Ideal Point showed that the majority of the study area has land index to the set of suitability between 0.50 and 0.60 and so many locations in the study region that are suitable for irrigated barley production have been found. The overall agreement between the Ideal point and observed yield Point maps is >90%. This agreement between the maps increases and the disagreement decreases while the resolution increases. The implications are that to obtain high agreement between the maps, it is necessary to go to higher resolutions. Also, the coefficients of correlation values between land indexes calculated by Ideal point method and observed yield were 0.88 and results are significant (P>5%).
Conclusion The Ideal Point approaches produce good results, accommodating to the uncertainties that are associated with boundary conditions in properties, and taking into account the effects of properties that happen to have weights near to cluster boundaries. Therefore, ideal point approaches produce good results because the Ideal Point approach has calculated some bias toward positive and negative ideal values.
