تغييرپذيري تناسب كيفي اراضي (روش پارامتريك ) در يك واحد نقشه خاك تفصيلي در منطقه فرخ شهر استان چهارمحال بختياري )

Variability of Qualitative Land Suitability Evaluation (Parametric method) in a Detailed Map Unit in Farrokhshahr Area, Chaharmahal method) in a Detailed Map Unit in Farrokhshahr Area, Chaharmahal

Quality of soil maps for different land uses is affected by variability of soils in the map units. Thus, accuracy of procedures used for crop recommendation would be questionable. This study was conducted for statistical evaluation of the procedure presented by Sys et al. (1991) for land suitability evaluation in Farrokhshahr area, Chaharmahal and Bakhtiari province. Results from thirty-one pedons in a selected detailed map unit was compared with the results obtained from representative pedon. Purity of suitability class was 16.1 and 24% at series and phases of series levels, respectively. According to cluster analysis, considering land indices, similar to that of the reference pedon, purity improves to 32.2 and 48%. These results also indicate that the use of land suitability class, because of its extended range and generalization of evaluation results derived from reference profile to the whole land unit, can be miss-leading considerably. For this reason, it is advised to take care in the interpretation of the results, at least when the suitability of a land is at the vicinity of the evaluated class indices. Also, due to low purity in soil map units, the use of this method in the level upper than phases of series level and also precision agriculture is not recommended. Combined new techniques like geostatistics, GIS and RS can be used to improve soil sampling and mapping methods.