Suitable Regions for Rain-Fed Tree Culture in Central Zagros (Chaharmahal-Bakhtiari Province of Iran)

There are many slopping lands in Chaharmahl-Bakhtiari Province of Iran, located in the central Zagros, which have suitable conditions for production of rain-fed horticultural products. This study was an attempt to determine the appropriate regions for almond and vine rain-fed cultivation in this province. Water requirement (ET) of the trees was calculated by local information of weather and plants. Annual precipitation (P) and ET were probabilistically analyzed. Required area for micro-catchment (Ac) and suitable regions for rain-fed gardening were then determined at different probability levels (p ) or return periods (T). Finally, average expected yields of almond and grape was estimated. Mapping the gardening-suitable area showed that inappropriate regions for rain-fed almond and vine culture are concentrated in the eastern part of the province due to less P and higher ET. Moreover, almond generally needed larger Ac than vine (about 43%) due to higher ET. Results also showed that increasing runoff coefficient (C) was more effective than enhancing water storage efficiency (E) in reducing required Ac, therefore, increasing 10% and 20% of C and E lead to 48% and 28% smaller Ac, respectively. Average required Ac for almond was calculated as 17.4 m2 which resulted in production of 549.0 kg/ha with p =50% (T=2). The corresponding values for the grape were 9.5 m2 and 2,128.8 kg/ha. Overall, the western areas in the province were more appropriate for rain-fed almond culture, whereas rain-fed vineyard gardens are preferred to be constructed in the eastern parts of the province.