modeling the limitative factors of forage production suitability using gis (case study: aliabad rangelands, lorestan, iran)

this research was conducted to identify the limitative factors of forage productionsuitability in order to achieve the sustainable exploitation of natural ecosystems in aliabadwatershed in lorestan in 2013. the field measurements have been done through cutting andweighing method to estimate the forage amount, four-factor method to determine the rangecondition, trend scale to specify the orientation and appearance, the plant cover percentmeasurement to categorize the types and desert scroll to separate the land units followed bythe classification. at last, all the digital maps of type, orientation, condition and forageproduction by the help of integration were changed into the final forage production suitabilitymap using specific software arcgis 9.3. results indicate that 6 separated vegetation typeshave been put in the suitability classes of s1, s2 and s3 for the areas of 972 ha (20.02%),3478 ha (71.62%) and 406 ha (8.36%), respectively and no part of the given rangelands wasplaced in non-suitability class (n). considering the results obtained from final suitabilitymodel of range production in this study, it has been found that high slope was the mostrestricting factor of range suitability. in addition, there were other decreasing factors such aslow percentage of vegetation, overgrazing, early grazing, nonconformity of livestock andrangeland balance and changes of ranges into low-yielding dry lands’ farming as well asforage production. it was concluded that the accuracy, simplicity and quickness can beconsidered as fundamental elements to determine the range suitability using geographicalinformation system (gis) which has been addressed in this study.