Effect of Salinity and Water Deficit Stresses on Biomass Production of Kochia (Kochia scoparia) and Trend of Soil Salinity

To determine whether Kochia can grow on marginal land irrigated with saline water, it was grown with six levels of saline water (1.5, 7, 14, 21, 28, and 35 dS/m) and three levels of applied water (AW) (25, 75, and 125 percent of the water requirement) in 2008 and four levels of applied water (50, 75, 100, and 125 percent) in 2009. Results showed that kochia produced considerable amounts of biomass (34 and 14 t DM ha-1) in 2009 and 2008 under suitable conditions, respectively. Under severe drought and salinity, kochia still could produce up to 16 and 8 t DM ha-1 in 2009 and 2008, respectively. Salinity tolerance of kochia was improved by increasing water application. Results of water depletion from different soil layers showed that Kochia could uptake more water from the 30-60 cm soil depth. The soil salinity (ECe) in this depth was lower in comparison to the 0-30 cm soil depth. Additionally, the water uptake from the 30-60 cm soil depth improved the level of salt tolerance of Kochia. The highest salt accumulation was observed in 60-90 cm soil depth. Results of this study demonstrated that Kochia should be considered as a forage crop or for production of biofuel using saline water in semi-arid areas.