Mohammad Reza Bahadori-Ghasroldashti - Water Engineering Department, School of Agriculture, Shiraz University, Shiraz, I.R. Iran
Fatemeh Razzaghi - Water Engineering Department, School of Agriculture, Shiraz University, I.R. Iran Drought Research Center, Shiraz University, I.R. Iran
Ali Reza Sepaskhah - Water Engineering Department, School of Agriculture, Shiraz University, I.R. Iran Drought Research Center, Shiraz University, I.R. Iran
Emmanuel Arthur - Department of Agroecology, Faculty of Technical Sciences, Aarhus University, Denmark

Faba bean, although, is widely cultivated, it’s yield is affected by drought and salinity stresses. Biochar can potentially reduce the negative effects of drought and salinity stress. In this study, the interaction effects of biochar, irrigation water regimes and irrigation water salinities on faba bean’s yield, crop water use efficiency (CWUE) and ion concentrations were evaluated under greenhouse condition. The treatments were biochar (۰, ۱.۲۵ and ۲.۵% w/w, as B۰, B۱.۲۵ and B۲.۵, respectively), irrigation water regime (۵۰, ۷۵ and ۱۰۰% of crop water requirement, as I۵۰%, I۷۵%, and I۱۰۰%, respectively) and irrigation water salinity (۰.۶, ۴ and ۸ dS m-۱, as S۰.۶, S۴ and S۸, respectively), that were arranged in a factorial arrangement using a complete randomized design with four replications. Biochar applied at ۲.۵% w/w significantly decreased actual crop evapotranspiration by ۱۱% in comparison with that obtained in B۰. The maximum dry seed yield (۱۴.۴ g pot-۱) was obtained under B۲.۵S۰.۶I۱۰۰% treatment. The CWUE of ۰.۴۷ kg m-۳ for B۲.۵S۸I۵۰% was ۱.۲۷ times that obtained in B۰S۰.۶I۱۰۰%. Seed sodium concentration under B۲.۵S۸I۵۰% (۰.۳۴ g kg-۱) was significantly lower than that obtained in B۰S۸I۵۰% (۰.۵۵ g kg-۱). Biochar application increased the plant tolerance to salinity, as the maximum threshold of soil saturated electrical conductivity of ۵.۲ dS m-۱ was observed under B۲.۵I۵۰% treatment, which was higher than ۲.۵ dS m-۱ obtained in B۰I۵۰% treatment. Finally, cultivation of faba bean under ۲.۵% w/w biochar and ۱۰۰% non-saline irrigation water level is recommended for maximum faba bean production.

Actual evapotranspiration, Sodium absorption ratio, Threshold of saturated electrical conductivity, Yield-salinity function