Nitrate, sulfur and sulfate concentrations in winter forage rape and perennial ryegrass and potential methane reduction from nitrate and sulfate.

a The number of field replicates of forage samples. Values are means ± SEM.bP value for the difference between forage rape and perennial ryegrass.c The reduction of 1 mol nitrate or 1 mol sulfate uses 4 mol H2, which decreases methane formation by 1 mol [19].d Detection limit for nitrate was 7.1 mmol/kg (100 mg N/kg). For the calculations of CH4 reductions and P values, it was assumed that nitrate-N was 7.0 mmol/kg.Nitrate, sulfur and sulfate concentrations in winter forage rape and perennial ryegrass and potential methane reduction from nitrate and sulfate.