development of zanjan province dry land wheat atlas by using climatic data and gis

abstract the goal of this survey is to prepare the dry land wheat atlas for zanjan province, according to the climate data. so we can recognize which areas are susceptible and to understand climate capabilities and limitations for dry land wheat. for reaching this purpose first raining and temperature datas of the research region were gathered and analyzed. at the first stage, proper according to the first rain after mehr which should have continued for 1 or 2 days and rained 5mm or more planting date was defined. then the different levels of dry planting wheat's growth was calculated by the gdd method. at the next stage the annual , autumn, spring and khordad's rainfall were reviewed and the average was calculated. the probability of germination temperatures, maximum temperature 25 and 30 degrees centigrade in the flowering stage and grain filling stage was also calculated. the calculated quantities in the gis system were converted into different arenas and by using the overlap method all layers were first given a weighing value and were incorporated afterwards. finally zanjan provinces dry land wheat atlas area with 4zones: very good, good, average and poor was prepared. as you can see in the map the most suitable regions for dry land wheat are in the center and north of khodabandeh and east of ijrood and of coarse the other parts of zanjan province are suitable. at the end the product producing scale is calculated and according to the neighbor provinces turnover scale which have the same weather and a higher turnover, the medium turnover and producing scale for zanjan was calculated which showed a 30% increase from the real production rate.