Figure 5. Mean SAR of shallow groundwater of columns irrigated with simulated Powder River and coal bed methane (CBM) water over time for Wytana saltbush. Water table positions were maintained at 114, 76, and 38 cm below the sand surface. Mean SAR of columns receiving Powder River water quality differed significantly from mean SAR of columns receiving CBM water quality at p=0.05. Columns receiving the same irrigation water quality and identified by the same letter are not significantly different at alpha = 0.05.