Forage quality characteristics of barley irrigated with coalbed methane water
Two experiments were conducted to determine the effects of coalbed methane (CBM) discharge water as an irrigation source in comparison with the use of well water. Three plot trials were conducted in two consecutive growing seasons with three replicates of 14 barley cultivars under each water treatment. Barley cultivars were grown under covered greenhouses to prevent uncontrolled precipitation. Each greenhouse received one of two water treatments: either well water (EC = 0.43 dS m-1, SAR = 0.25) or synthesized CBM discharge water (EC = 1.6 dS m-1, SAR = 35). Plots were irrigated with 5.1 cm of respective treatment water on the day of seeding and flood irrigated with treatment water on a weekly basis. Cultivars were sampled on three cutting dates within each trial, when the majority of the entries were in the boot, anthesis, and milk stages of maturity. Barley forage was analyzed for yield, height, and forage quality with relation to livestock requirements. Cultivars were dried, ground and analyzed for yield, dry matter (DM), acid detergent fiber (ADF), neutral detergent fiber (NDF), crude protein (CP), nitrate (NO3-N) concentrations, in vitro dry matter digestibility (IVDMD), and mineral concentrations. Coalbed methane discharge water significantly reduced (P<0.10) barley forage yield, height, and NO3-N concentrations. Forages irrigated with well water yielded higher (P<0.10) than those irrigated with CBM water (6499 vs 4937 kg ha-1) and were taller (49 vs 36 cm). Nitrate concentrations were lower (P<.010) in forages irrigated with CBM water than well water (0.66 vs 3.3 mg g-1). No differences (P>0.10) were seen between water treatments for the remaining parameters. Use of CBM discharge water as an irrigation source reduced yield, had a negative impact on height, and CP concentrations and reduced nitrate concentrations. Few differences were detected in mineral concentrations between water treatments. More research is necessary to determine the long term impacts of CBM discharge water on soil and plant quality.