Assessment of Cropped Area, and Cropping Intensity in Hamedan- Bahar Plain Using Remote Sensing Data

Cropped area، crop pattern and cropping intensity maps are the most important components of the water requirements in basin scale and also are the most difficult to measure. Conventional methods are very local، ranging from region to field scale. Estimates of the cropped area and crop pattern over the entire area، especially for irrigated areas، are essential، as these can differ substantially depending on the crop pattern and the management applied. Today، actual cropped area، crop pattern and cropping intensity under different conditions can be estimated by using satellites and remote sensing (RS) techniques. In order to obtain the crop pattern and cropping intensity، a set of satellite images was used. From a set of Landsat 7 images، NDVI and SAVI indicators were established. Based on these indicators the actual cropped area and cropping intensities were estimated and compared by cropped area that reported by agricultural organization in Hamedan–Bahar plain of Hamedan province. Results indicated that، the actual cropped area using remote sensing data was equal with irrigated area that reported by agricultural organization in summer season (27/05/79)، but in the other season the reported area was more than the actual cropped area. The reported cropped area was 1. 2 time of total irrigated area of Hamedan–Bahar plain. Cropped intensity of Hamedan–Bahar plain is between 63 and 75%، but cropping intensities can be much higher as a substantial area is used to grow two crops. Main winter crops are wheat and barley، summer crops are corn، potato and vegetables. The main advantage of the remote sensing approach applied here is that it is a nonspecific one and can be easily adapted to other conditions in terms of soil، weather، and crop. Besides the benefits of this non-specific approach، the methodology applied here gives a wealth of information in comparison to field trials، in terms of spatial and temporal resolution as well as in terms of difficult to measure processes such as cropped area، crop pattern، and cropping intensities.