8th International Soil Science Congress on "Land Degradation and Challenges in Sustainable Soil management" May 15-17, 2012 Çeşme-İzmir, TURKEY PROCEEDINGS BOOK http://www.soilcongress.ege.edu.tr POLICIES FOR SOIL HEALTH MANAGEMENT IN AGRICULTURE ϰϱ Evaluation of physiological growth stage of faba bean to drought * Shamil Y. H. M. A Al-Hamdany ** Caser G. Abdel * Horticulture Department, Agriculture & Forestry College, Mosul University, Mosul, Iraq ** Horticulture Department, Agriculture College, Dohuk University, Kurdistan Region, Iraq Abstract: This study was carried out during fall season of (2003 - 2004) at Danadan Research Station, Mosul University , Mosul city center. The experiment were included in this investigation to evaluate the response of faba bean cultivars namely (French, Syrian, Tacka357, Towaytha and Babylon) and therefore the experiment was conducted to study the designed to detect which plant physiological stage is the most sensitive to water stress and thus complementary watering was ceased either during (Vegetative, Flowering or pod growth and seed filling stages). The results showed that Pod development and filling stage appeared to be the most water stress sensitive stage a sit showed a reduction of (97.91 cm) in plant height and (21.08 cm) in pod length and (4.78) in number of seed / pod and (559.76 g-m-2) in dry pods weight and (434.39 g-m-2 ) in dry seed yield and (144.53 g) in 100 seed weight as compared to check. So we can concluded that we have to irrigate the plants very well till ripening of pods and seed to get a good quality. French and Syrian cultivars might be classified as semi conservative cultivars since they have the ability to keep partial stomata close for CO2 exchange to match with normal photosynthesis accompanied by significant transpiration reduction, while Towaytha and Babylon cultivars appeared to be conservative cultivars. The determinate Tacka 375 cultivar could be categorized as drought escapable cultivar since it matures nearly more than two weeks before the other corresponding cultivars. Introduction Faba bean Vicia faba L. crop is Mediterranean basin origin (Summer field and Roberts, 1985). However, faba bean production in this region facing serious problems owing to the synchronization of rapid temperature increases accompanied by low rainfall incidences with fruit setting, pod development and seed filling at the end of the growing season (Loss and Siddique, 1996 and Abdel, 1997).China is the highest faba bean producer and consumer as well where it produces (2.7 ton.year-1) which constitute (65%) of the overall global faba bean production , followed by Ethiopia (9%) and Egypt in the third order as it produces (262 ton.year-1). However, in Iraq, faba bean is a secondary crop and it consumed as boiled green mature pods or boiled seed (Abdel, 1993). Recently, (consumptions are increased since it possesses a relatively high protein content 23-42% (Stan, 1997), and considered the highest protein producing legume crops owing its higher yield 5 t.ha-1 (Schulz et al., 1999). In area where supplementary irrigation is required such as Northern Iraqi provinces where the water demand at varying physiological phases is of high significance in order to aid faba bean plants during the critical stage to ovoid yield reductions (Abdel, 1997). Subsequently Faba bean growth was categorized to vegetative, flowering, fruit setting, pod swelling and seed filling phases; it was found that pod swelling and seed filling were the most critical drought susceptible stages (El- Nadi et al, 1969). However , vegetative stage was found to be less effective and manifested the recovering capability (El-Nadi, 1970) , followed by flowering stage which was found to be less sensitive than on coming stage owing to the ability of Faba bean plants to produce profuse number of flower where setting of (10%) of these flower may be adequate to ensure sufficient pod number. Therefore, pod swelling and seed fillings are the most drought susceptible stages where watering should be applied if which otherwise yield would be greatiy reduced (Doss et al., 1974 and Milburn, 1974). Sustaining adequate watering during pod swelling and seed filling stages resulted in maximum faba bean yield (French et al., 1976; Sprent et al., 1977; Nairizi and Rydzewski, 1977). Moreover Stock (1977) obtained the highest yield with adequate watering from flowering to harvesting. Faba bean production risk maintained throughout the growing season unless the seeds are completely matured (El-Sarrag et al., 1988; Abdel, 1993). Yield reducation was reported when plants were exposed water scarcity during flowering stage (Sparrow et al., 1995; Sanders, 1997). The attributed their results to the influence of drought on nitrogenase activity. Mwanamwenge et al. (1999) confirmed the significance of irrigating faba bean plants during pod swelling and seed fillings. The objective of this investigation was to detect the yield reduction that resulted from irrigation casement during varying growth phases of five faba bean cultivars in order to improve water consumptive use and water use efficiency.