spatial prioritizing of the onion producing in warm and arid regions (case study: sistan and bluchestan province)

achieving the self-sufficiency in producing agricultural crops and decreasing the pressure on the available water resources need determining the fertile places for cultivation based on the suitable evaluating indices. in this research, the prioritization of different township in sistan and blouchestan province for onion cultivation, as one of the most important production in the province, was carried out. in order to, the weather data, yield, cultivated area and irrigation method were used through 2000 to 2011. the prioritizing was done based on virtual water, unit water value and economical irrigation water use efficiency indices. sistan and bluchestan was self-sufficient in onion producing. the 12-year average excess onion production was 38.6 thousand ton, 70 percentages of which was produced in sarbaz and chabahar townships. more than 65 percentages of the onion cultivated area are located in the suitable cultivation class based on the evaluating indices. however, decreasing the cultivated area in konarak, chabahar and iranshahr and allocating them to sarbaz or khash would considerably increase the annual return of onion cultivation. the result showed that applying a suitable spatial cultivation management and promoting the irrigation efficiency to 85 percentages would increase the economical irrigation water use efficiency by 123.68 percentages which would led to 13554.9 to 56809.2 rs increase in the economic return of onion cultivation per unit cub meter water use.